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+The Project Gutenberg EBook of Being Well-Born, by Michael F. Guyer
+
+This eBook is for the use of anyone anywhere at no cost and with
+almost no restrictions whatsoever.  You may copy it, give it away or
+re-use it under the terms of the Project Gutenberg License included
+with this eBook or online at www.gutenberg.org
+
+
+Title: Being Well-Born
+       An Introduction to Eugenics
+
+Author: Michael F. Guyer
+
+Editor: M. V. O'Shea
+
+Release Date: May 21, 2012 [EBook #39751]
+
+Language: English
+
+Character set encoding: ISO-8859-1
+
+*** START OF THIS PROJECT GUTENBERG EBOOK BEING WELL-BORN ***
+
+
+
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+Produced by Bryan Ness and the Online Distributed
+Proofreading Team at http://www.pgdp.net (This file was
+produced from images generously made available by The
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+
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+
+
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+
+
+
+BEING WELL-BORN
+
+
+
+
+  BEING WELL-BORN
+
+  AN INTRODUCTION TO EUGENICS
+
+
+  _By_
+  MICHAEL F. GUYER, PH. D.
+  Professor of Zoology, The University of Wisconsin
+
+
+  Childhood and Youth Series
+
+  _Edited by_ M. V. O'SHEA
+  Professor of Education, The University of Wisconsin
+
+
+  INDIANAPOLIS
+  THE BOBBS-MERRILL COMPANY
+  PUBLISHERS
+
+
+
+
+  COPYRIGHT 1916
+  THE BOBBS-MERRILL COMPANY
+
+  PRESS OF
+  BRAUNWORTH & CO.
+  BOOKBINDERS AND PRINTERS
+  BROOKLYN, N. Y.
+
+
+
+
+TO MY WIFE
+
+HELEN M. GUYER
+
+
+
+
+EDITOR'S INTRODUCTION
+
+
+The writer recalls that when he was a young boy, he heard the grown-up
+people in the community earnestly and incessantly debating the question:
+Does heredity play a greater part in shaping one's mind and body than does
+his environment? From that day to this he has listened to men and women in
+every walk of life discussing the relation of heredity to environment in
+determining human traits. Teachers and parents are constantly asking: "Are
+such and such characteristics in my children due to their inheritance or
+to the way they have been trained?" Students of juvenile delinquency and
+of mental defect and deficiency are searching everywhere for light on this
+matter. It is not to be wondered at that practically all people are
+peculiarly interested in this problem, since it concerns intimately one's
+personal traits, and it constantly confronts any one who is responsible
+for the care and culture of the young.
+
+It is suggestive to note how people differ in their views regarding the
+extent to which a child's physical and mental qualities and capacities are
+fixed definitely by his inheritance. The writer has often heard students
+in university classes discuss the subject; and their handling of the
+problem has shown how superficially and even superstitiously most persons
+regard the mechanism and functions of heredity. It is significant also to
+observe what extreme views many people hold regarding the possibility of
+affecting a child's traits and abilities by subjecting him to specific
+influences during his prenatal life. In any group of one hundred persons
+chosen at random, probably seventy-five will believe in specific prenatal
+influence. Many of them will believe in birthmarks due to peculiar
+experiences of the mother. A popular book recently published asserts among
+other things that if a mother will look upon beautiful pictures and listen
+to good music during the prenatal period of her child, the latter will
+possess esthetic traits and interests in high degree. On the other hand,
+people generally do not seem to think that degenerate parents beget only
+degenerate children. Alcoholics, feeble-minded persons and the like are
+permitted to bring children into the world.
+
+Very few people have any precise knowledge of the mechanism of heredity.
+The whole thing is inscrutable to them, and is shrouded in mystery.
+Superstition flourishes among even intelligent persons in respect to
+heredity, and errors due to education, and tragedies resulting from
+vicious social organization are all alike ascribed to its uncontrollable
+forces. Most people are none the wiser because they do not know to what
+extent the physical and mental defects and deviations of individuals are
+due to inheritance or to the malign influences of the individual's
+environment and training.
+
+Professor Guyer, who has studied the whole problem in a thoroughgoing,
+scientific way, has prepared this book with a view to illuminating some of
+the mysteries that surround the subject of heredity, and to dispelling
+the illusions that persist regarding it. He shows the method which nature
+follows in the development of the individual. He presents the laws which
+have become established respecting the extent to which and the manner in
+which immediate and remote ancestors contribute to the child's physical
+and mental organism. He answers many questions which those who are engaged
+in social work or in education in the home or the school are asking
+to-day. He discusses subjects upon which every serious-minded person
+wishes to be informed. He has thus made a book which is both of
+theoretical and of practical interest.
+
+He has written in a style which should make his book attractive to the
+parent and the teacher as well as to the student of the complicated
+mechanism of inheritance. Only a few special terms are used, and these
+should not give any reader trouble, because the treatment throughout is so
+concrete that the meaning of the terms will be easily grasped. Further,
+the book is illustrated, with many attractive and instructive
+illustrations which will show at a glance the working of the principles of
+inheritance which are developed in the text.
+
+This book may be heartily commended to all who are interested in questions
+of human nature, education and social reform. It should enable the parent,
+the teacher and the legislator to understand more clearly than most of
+them now do in how far children's traits and possibilities are or can be
+fixed by inheritance as contrasted with environmental conditions and
+nurture in home, school, church and institutional life.
+
+M. V. O'SHEA.
+
+Madison, Wisconsin.
+
+
+
+
+PREFACE
+
+
+One of the most significant processes at work in society to-day is the
+awakening of the civilized world to the rights of the child; and it is
+coming to be realized that its right of rights is that of being well-born.
+Any series of publications, therefore, dealing primarily with the problems
+of child nature may very fittingly be initiated by a discussion of the
+factor of well-nigh supreme importance in determining this nature,
+heredity.
+
+No principles have more direct bearing on the welfare of man than those of
+heredity, and yet on scarcely any subject does as wide-spread ignorance
+prevail. This is due in part to the complexity of the subject, but more to
+the fact that in the past no clear-cut methods of attacking the manifold
+problems involved had been devised. Happily this difficulty has at least
+in part been overcome.
+
+It is no exaggeration to say that during the last fifteen years we have
+made more progress in measuring the extent of inheritance and in
+determining its elemental factors than in all previous time. Instead of
+dealing wholly now with vague general impressions and speculations,
+certain definite principles of genetic transmission have been disclosed.
+And since it is becoming more and more apparent that these hold for man as
+well as for plants and animals in general, we can no longer ignore the
+social responsibilities which the new facts thrust upon us.
+
+Since what a child becomes is determined so largely by its inborn
+capacities it is of the greatest importance that teachers and parents
+realize something of the nature of such aptitudes before they begin to
+awaken them. For education consists in large measure in applying the
+stimuli necessary to set going these potentialities and of affording
+opportunity for their expression. Of the good propensities, some will
+require merely the start, others will need to be fostered and coaxed into
+permanence through the stereotyping effects of proper habits; of the
+dangerous or bad, some must be kept dormant by preventing improper
+stimulation, others repressed by the cultivation of inhibitive tendencies,
+and yet others smothered or excluded by filling their place with desirable
+traits before they themselves come into expression.
+
+We must see clearly, furthermore, that even the best of pedagogy and
+parental training has obvious limits. Once grasp the truth that a child's
+fate in life is frequently decided long before birth, and that no amount
+of food or hospital service or culture or tears will ever wholly make good
+the deficiencies of bad "blood," or in the language of the biologist, a
+faulty germ-plasm, and the conviction must surely be borne home to the
+intelligent members of society that one thing of superlative importance in
+life is the making of a wise choice of a marriage mate on the one hand,
+and the prevention of parenthood to the obviously unfit on the other.
+
+In the present volume it is intended to examine into the natural
+endowment of the child. And since full comprehension of it requires some
+understanding of the nature of the physical mechanism by which hereditary
+traits are handed on from generation to generation, a small amount of
+space is given to this phase. Then, that the reader may appreciate to
+their fullest extent the facts gathered concerning man, a review of the
+more significant principles of genetics as revealed through experiments in
+breeding plants and animals has been undertaken. The main applications of
+these principles to man is pointed out in a general discussion of human
+heredity. Finally, inasmuch as all available data indicate that the fate
+of our very civilization hangs on the issue, the work concludes with an
+account of the new science of eugenics which is striving for the
+betterment of the race by determining and promulgating the laws of human
+inheritance so that mankind may intelligently go about conserving good and
+repressing bad human stocks.
+
+In order to eliminate as many errors as possible and to avoid oversights I
+have submitted various chapters to certain of my colleagues and friends
+who are authorities in the special field treated therein. While these
+gentlemen are in no way responsible for the material of any chapter they
+have added greatly to the value of the whole by their suggestions and
+comments. Thus I am indebted to Professor Leon J. Cole for reading the
+entire manuscript; to Professors A. S. Pearse and F. C. Sharp for reading
+Chapter VII; to Professor C. R. Bardeen for reading special parts; to
+Doctor J. S. Evans for reading Chapter VI and part of V; to Doctor W. F.
+Lorenz, of the Mendota Hospital, for reading Chapter VIII; to Judge E. Ray
+Stevens for reading Chapter IX, and to Helen M. Guyer for several readings
+of the entire manuscript.
+
+Grateful acknowledgment is made to all of these readers, to various
+publishers and periodicals for the use of certain of the illustrations, to
+the authors of the numerous books and papers from which much of the
+material in such a work as this must necessarily be selected, and to my
+artist, Miss H. J. Wakeman, for her painstaking endeavors to make her work
+conform to my ideas of what each diagram should show.
+
+M. F. G.
+
+
+
+
+CONTENTS
+
+
+  CHAPTER                                                             PAGE
+
+  I HEREDITY                                                             1
+
+  Blood heritage--Kind determined by origin--Ancestry a network--
+  Ancestry in royalty--Offspring derived from one parent only--Dual
+  ancestry an aid in studying heredity--Reversion--Telegony--
+  Prenatal influences apart from heredity--Parent body and germ not
+  identical--A hereditary character defined--Hereditary mingling a
+  mosaic rather than a blend--Determiners of characters, not
+  characters themselves, transmitted--Our knowledge of heredity
+  derived along three lines--The method of experimental breeding--
+  The statistical method--Galton's law of regression--Correlations
+  between parents and offspring--The biometrical method,
+  statistical, not physiological--Mental as well as physical
+  qualities inheritable.
+
+
+  II THE BEARERS OF THE HERITAGE                                        20
+
+  The cell the unit of structure--Unicellular organisms--Importance
+  of cell-theory--Heredity in unicellular forms--Reproduction and
+  heredity in colonial protozoa--Conjugation--Specialization of
+  sex-cells--The fertilized ovum--Advancement seen in the Volvox
+  colony--Natural death--Specialization in higher organisms--Sexual
+  phenomena in higher forms--Cell-division--Chromosomes constant in
+  number and appearance--Significance of the chromosomes--Cleavage
+  of the egg--Chief processes operative in building the body--The
+  origin of the new germ-cells--Significance of the early setting
+  apart of the germ-cells--Individuality of chromosomes--Pairs of
+  chromosomes--Reduction of the number of chromosomes by one-half--
+  Maturation of the sperm-cell--Maturation of the egg-cell--Parallel
+  between the two processes--Fertilization--Significance of the
+  behavior of the chromosomes--A single set of chromosomes
+  sufficient for the production of an organism--The duality of the
+  body and the singleness of the germ--The cytoplasm in
+  inheritance--Chromosomes possibly responsible for the
+  distinctiveness of given characters--Sex and heredity--Many
+  theories of sex determination--The sex-chromosome--Sex-linked
+  characters in man--In lower forms.
+
+  III MENDELISM                                                         67
+
+  New discoveries in the field of heredity--Mendel--Rediscovery of
+  Mendelian principles--Independence of inheritable characters--
+  Illustration in the Andalusian fowl--The cause of the ratio--
+  Verification of the hypothesis--Dominant and recessive--
+  Segregation in the next generation--Illustrated in guinea-pigs--
+  Terminology--The theory of presence and absence--Additional
+  terminology--Dominance not always complete--Modifications of
+  dominance--Mendel's own work--Dihybrids--Getting new combinations
+  of characters--Segregations of the determiners--Four kinds of
+  gametes in each sex--The 9:3:3:1 ratio--Phenotype and genotype--
+  The question of blended inheritance--Nilsson-Ehle's discoveries--
+  Such cases easily mistaken for true blends--Skin-color in man--
+  Questionable if real blends exist--The place of the Mendelian
+  factors in the germ-cell--Parallel between the behavior of
+  Mendelian factors and chromosomes--A single chromosome not
+  restricted to carrying a single determiner.
+
+  IV MENDELISM IN MAN                                                   97
+
+  Probably applicable to many characters in man--Difficult to get
+  correct data--A generalized presence-absence formula--Indications
+  of incomplete dominance--Why after the first generation only half
+  the children may show the dominant character--Eye-color in man--
+  Hair-color--Hair-shape--Irregularities--Digital malformations--Eye
+  defects--Other defects inherited as dominants--Recessive
+  conditions more difficult to deal with--Albinism--Other recessive
+  conditions in man--Breeding out defects--Other inheritable
+  conditions in man.
+
+  V ARE MODIFICATIONS ACQUIRED DIRECTLY BY THE BODY INHERITED?         121
+
+  Which new characters are inherited?--Examples of somatic
+  modifications--Use and disuse--The problem stated--Special
+  conditions in mammals--Three fundamental questions--External
+  influences may directly affect the germ-cells--Such effects
+  improbable in warm-blooded animals--Poisons may affect the
+  germ-plasm--How can somatic modifications be registered in
+  germ-cells?--Persistence of Mendelian factors argues against such
+  a mode of inheritance--Experiments on insects--On plants--On
+  vertebrates--Epilepsy in guinea-pigs--Effects of mutilations not
+  inherited--Transplantation of gonads--Effects of body on germ,
+  general not specific--Certain characters inexplicable as inherited
+  somatic acquirements--Neuter insects--Origin of new characters in
+  germinal variation--Sexual reproduction in relation to new
+  characters--Many features of an organism characterized by
+  utility--Germinal variation a simpler and more inclusive
+  explanation--Analysis of cases--Effects of training--Instincts--
+  Disease--Reappearance not necessarily inheritance--Prenatal
+  infection not inheritance--Inheritance of a predisposition not
+  inheritance of a disease--Tuberculosis--Two individuals of
+  tubercular stock should not marry--Special susceptibility less of
+  a factor in many diseases--Deaf-mutism--Gout--Nervous and mental
+  diseases--Other disorders which have hereditary aspects--Induced
+  immunity not inherited--Social, ethical and educational
+  significance of non-inheritance of somatic modifications--No cause
+  for discouragement--Improved environment will help conserve
+  superior strains when they do appear.
+
+  VI PRENATAL INFLUENCES                                               151
+
+  All that a child possesses at birth not necessarily hereditary--
+  The myth of maternal impressions--Injurious prenatal influences--
+  Lead poisoning--The expectant mother should have rest--Too short
+  intervals between children--Expectant mothers neglected--
+  Alcoholism--Unreliability of most data--Alcohol a germinal and
+  fetal poison--Various views of specialists on the effects of
+  alcoholism on progeny--The affinity of alcohol for germinal
+  tissue--Innate degeneracy versus the effects of alcohol--
+  Experimental alcoholism in lower animals--Further remarks on the
+  situation in man--Much inebriety in man due to defective nervous
+  constitution--Factors to be reckoned with in the study of
+  alcoholism--Venereal diseases--The seriousness of the situation--
+  Infantile blindness--Syphilis--Some of the effects--A blood test--
+  Many syphilitics married--Why permit existing conditions to
+  continue?--Ante-nuptial medical inspection--The perils of venereal
+  disease must be prevented at any cost--Bad environment can wreck
+  good germ-plasm.
+
+  VII RESPONSIBILITY FOR CONDUCT                                       195
+
+  All mental process accompanied by neural process--Gradations in
+  nervous response from lower organisms to man--Behavior of many
+  animals often an automatic adjustment to simple external agents--
+  Tropisms--Certain apparently complex volitions probably only
+  tropisms--Complicating factors--Many tropic responses apparently
+  purposeful--Tropisms grade into reflex actions and instincts--
+  Adjustability of instincts opens the way for intelligent
+  behavior--Modification of habits possible in lower animals--Some
+  lower vertebrates profit by experience--Rational behavior--
+  Conceptual thought probably an outgrowth of simpler psychic
+  states--The capacity for alternative action in higher animals--The
+  elemental units of the nervous system are the same in lower and
+  higher animals--Neuron theory--Establishment of pathways through
+  the nervous system--Characteristic arrangements of nerve cells
+  subject to inheritance--Different parts of the cortex yield
+  different reactions--Skill acquired in one branch of learning
+  probably not transferred to another branch--Preponderance of
+  cortex in highest animals--Special fiber tracts in the spinal cord
+  of man and higher apes--Great complexity in associations and more
+  neurons in the brain of man--The nervous system in the main
+  already staged at the time of birth--Many pathways of conduction
+  not yet established--The extent of the modifiable zone unknown--
+  Various possibilities of reaction in the child--Probable origin of
+  altruistic human conduct--Training in motive necessary--Actual
+  practise in carrying out projects important--Interest and
+  difficulty both essential--The realization of certain
+  possibilities of the germ rather than others is subject to
+  control--We must afford the opportunity and provide the proper
+  stimuli for the development of good traits--Moral responsibility.
+
+  VIII MENTAL AND NERVOUS DEFECTS                                      228
+
+  Prevalence of insanity--Imperfect adjustments of the brain
+  mechanism inheritable--Many mental defectives married--
+  Disproportionate increase in number of mental defectives--Protests
+  voiced by alienists--Examples of hereditary feeble-mindedness--
+  Difficult to secure accurate data--Feeble-mindedness and insanity
+  not the same--Many types of insanity--Not all insanities of the
+  same eugenical significance--Difficulties of getting genealogies
+  of specific forms of insanity--Certain forms of insanity seem to
+  behave as Mendelian recessives--Grades of feeble-mindedness--About
+  two-thirds of feeble-mindedness inherited--Some results of
+  non-restraint of the feeble-minded--Not all cases of mental
+  deficiency inherited--Epileptics--Feeble-mindedness probably a
+  recessive--Many apparently normal people are carriers of
+  neuropathic defects--Tests for mental deficiency--The backward
+  child in school--The exceptionally able child--Cost of caring for
+  our mentally disordered--Importance of rigid segregation of the
+  feeble-minded--Importance of early diagnosis of insanity--Opinion
+  of competent psychiatrists essential--Some insanities not
+  hereditary--Importance of heredity in insanity not appreciated.
+
+  IX CRIME AND DELINQUENCY                                             263
+
+  Heredity and environment in this field--Feeble-mindedness often a
+  factor--Many delinquent girls mentally deficient--Institutional
+  figures misleading--Many prisoners mentally subnormal--Inhibitions
+  necessary to social welfare--The high-grade moron a difficult
+  problem--Degenerate strains--Intensification of defects by
+  inbreeding--Vicious surroundings not a sufficient explanation in
+  degenerate stocks--Not all delinquents defectives--No special
+  inheritable crime-factor--What is a born criminal?--Epileptic
+  criminal especially dangerous--The mental disorders most
+  frequently associated with crime--Bearing of immigration on crime
+  and delinquency--Sexual vice--School instruction in sex-hygiene--
+  Mere knowledge not the crux of the sex problem--Early training in
+  self-restraint an important preventive of crime and delinquency--
+  Multiplication of delinquent defectives must be prevented.
+
+  X RACE BETTERMENT THROUGH HEREDITY                                   289
+
+  Questionable charity--Past protests--An increasing flood of
+  defectives--Natural elimination of defectives done away with--Why
+  not prevent our social maladies?--Eugenics defined--Improved
+  environment alone will not cure racial degeneracy--Heredity and
+  environment--Inter-racial marriage--Human conservation--Kindness
+  in the long run--The problem has two phases--Constructive eugenics
+  must be based on education--Inferior increasing more rapidly than
+  superior stocks--An unselected population may contain much
+  valuable material--The lack of criteria for judging fitness--The
+  college graduate--Native ability, independence and energy
+  eugenically desirable--Four children to each marriage required to
+  maintain a stock--Factors contributing to low birth-rate in
+  desirable strains--The educated public must be made to realize the
+  situation--Utilization of family pride as a basis for constructive
+  eugenics--The tendency for like to marry like--Public opinion as
+  an incentive to action--Choosing a marriage mate means choosing a
+  parent--The best eugenic marriage also a love match--The
+  elimination of the grossly unfit urgent--Suggested remedies--
+  Inefficacy of laws which forbid marriage of mental defectives--
+  Systems of mating impracticable in the main--Corrective mating
+  presupposes knowledge of eugenics--Segregation has many
+  advocates--Sterilization as a eugenic measure--To what conditions
+  applicable--In insanity--In feeble-mindedness--In cases of
+  epilepsy--Sterilization laws--Social dangers in vasectomy--Our
+  present knowledge insufficient--Sterilization laws on trial--An
+  educated public sentiment the most valuable eugenic agent--The
+  question of personal liberty--Education of women in eugenics
+  needed--Much yet to be done--A working program--Which shall it be?
+
+  GLOSSARY                                                             343
+
+  REFERENCES FOR FURTHER READING AND STUDY                             355
+
+  INDEX                                                                361
+
+
+
+
+BEING WELL-BORN
+
+
+
+
+CHAPTER I
+
+HEREDITY
+
+
+It is a commonplace fact that offspring tend to resemble their parents. So
+commonplace, indeed, that few stop to wonder at it. No one misunderstands
+us when we say that such and such a young man is "a chip off the old
+block," for that is simply an emphatic way of stating that he resembles
+one or the other of his parents. The same is true of such familiar
+expressions as "what's bred in the bone," "blood will tell," and kindred
+catch phrases. All are but recognitions of the same common fact that
+offspring exhibit various characteristics similar to those of their
+progenitors.
+
+=Blood Heritage.--=To this phenomenon of resemblance in successive
+generations based on ancestry the term heredity is applied. In man, for
+instance, there is a marked tendency toward the reappearance in offspring
+of structures, habits, features, and even personal mannerisms, minute
+physical defects, and intimate mental peculiarities like those possessed
+by their parents or more remote forebears. These personal characteristics
+based on descent from a common source are what we may call the blood
+heritage of the child to discriminate it from a wholly different kind of
+inheritance, namely, the passing on from one generation to the next of
+such material things as personal property or real estate.
+
+=Kind Determined by Origin.--=It is inheritance in the sense of community
+of origin that determines whether a given living creature shall be man,
+beast, bird, fish, or what not. A given individual is human because his
+ancestors were human. In addition to this stock supply of human qualities
+he has certain well-marked features which we recognize as characteristics
+of race. That is, if he is of Anglo-Saxon or Italian or Mongolian
+parentage, naturally his various qualities will be Anglo-Saxon, Italian,
+or Mongolian. Still further, he has many distinctive features of mind and
+body that we recognize as family traits and lastly, his personal
+characteristics such as designate him to us as Tom, Harry, or James must
+be added. The latter would include such minutiæ as size and shape of ears,
+nose or hands; complexion; perhaps even certain defects; voice; color of
+eyes; and a thousand other particulars. Although we designate these
+manifold items as individual, they are in reality largely more or less
+duplicates of similar features that occur in one or the other of his
+progenitors, features which he would not have in their existing form but
+for the hereditary relation between him and them.
+
+  "O Damsel Dorothy! Dorothy Q.!
+  Strange is the gift that I owe to you;
+
+    *       *       *       *       *
+
+  What if a hundred years ago
+  Those close-shut lips had answered 'No,'
+
+    *       *       *       *       *
+
+  Should I be I, or would it be
+  One-tenth another, to nine-tenths me?"
+
+  "Soft is the breath of a maiden's yes;
+  Not the light gossamer stirs with less;
+  But never a cable that holds so fast
+  Through all the battles of wave and blast,
+  And never an echo of speech or song
+  That lives in the babbling air so long!
+  There were tones in the voice that whispered then
+  You may hear to-day in a hundred men."
+
+When life steps into the world of matter there comes with it a sort of
+physical immortality, so to speak; not of the individual, it is true, but
+of the race. But the important thing to note is that the race is made up,
+not of a succession of wholly unrelated forms, but a continuation of the
+same kind of living organisms, and this sameness is due to the actual
+physical descent of each new individual from a predecessor. In other
+words, any living organism is the kind of organism it is in virtue of its
+hereditary relation to its ancestors.
+
+It is part of the biologist's task to seek a material basis, a continuity
+of actual substance, for this continuity of life and form between an
+organism and its offspring. Moreover, inasmuch as the offspring is never
+precisely similar to its progenitors he must determine also what qualities
+are susceptible of transmission and in what measure.
+
+=Ancestry a Network.--=From the fact that each child has all of the
+ancestors of its mother as well as of its father, arises the great
+complications which are met with in determining the lineage of an
+individual. A person has two parents, four grandparents, eight great
+grandparents, and thus following out pedigree it is plain to be seen that
+through this process of doubling in each generation, in the course of a
+few centuries one's ancestry is apparently enormous. By actual
+computation, according to Professor D. S. Jordan, if we count thirty
+generations back to the Norman invasion of England in 1066, at this ratio
+of duplication, the child of to-day would have had at that time an
+ancestry of 8,598,094,592 persons. But we know that the total number of
+inhabitants in England during the time of William the Conqueror was but a
+small fraction of this enormous aggregate. This means that we shall have
+to modify our inference that a child has twice as many ancestors as its
+parents; a condition which at first sight seems evident, but which is not
+literally true. The fact is that the parents of the child, in all
+probability, have many ancestors in common--a state of affairs which is
+brought about through the intermarriage of relatives, and this is
+especially frequent among remoter descendants of common progenitors. Time
+after time in genealogy strains of blood have crossed and recrossed until
+it is not improbable that a man of to-day who is of English origin has the
+blood in his veins from every inhabitant of England who lived during the
+time of William the Conqueror and left fruitful descendants. Instead of
+conceiving of ancestry as an ever branching and widening tree-like system
+as it recedes into the past, it is more accurate, therefore, to regard it
+in the light of an elaborate meshwork. The "family tree" in reality
+becomes the family net.
+
+=Ancestry in Royalty.--=The pedigrees of royal families have proved to be
+of much importance in the study of human inheritance, not that royal
+traits are any more heritable than any other, but simply because the
+records have been carefully kept so that they are the most comprehensive
+and easily followed pedigrees available. The netlike weave of ancestry is
+particularly well exemplified in some of these families because of much
+close intermarriage. Their heritage typifies on an intensified scale the
+heritage of the mass of mankind. For example, if we go six generations
+back in the ancestry of Frederick the Great instead of the expected
+sixty-four individual ancestors we find only forty; or in a still more
+closely woven stock, in the Spanish royal line of Don Carlos we find in
+six generations instead of sixty-four individual ancestors, only
+twenty-eight. While the present German emperor might have had four
+thousand ninety-six ancestors in the twelfth generation back, it is
+estimated that owing to intermarriage he probably had only five hundred
+thirty-three.
+
+=Offspring Derived from One Parent Only.--=So far in our reckoning of
+heredity we have counted elements from both father and mother, and the
+complications which arise from such a double ancestry are manifestly very
+perplexing ones. If we could do away with the elements of sex and find
+offspring that are derived from one parent only, it would seemingly
+simplify our problem very much for we should thus have a direct line of
+descent, free from intermingling. This, in fact, occurs to a greater or
+less extent among lower animals in a number of instances. There may be
+only female forms for a number of generations and the eggs which they
+produce develop directly into new individuals. Moreover, many of the
+simpler organisms have the power of dividing their bodies into two and
+thus giving rise to two new forms, each of which resembles the parent.
+This shows plainly that we may have inheritance without the appearance of
+any male ancestor at all, hence sex is not always a necessary factor in
+reproduction or heredity. The development of eggs asexually, that is,
+without uniting first with a male cognate, is termed _parthenogenesis_.
+The ordinary plant louse or aphid which is frequently found upon geraniums
+is a familiar example of an animal which reproduces largely in this way.
+During the summer only the females exist and they are so astonishingly
+fertile that one such aphid and her progeny, supposing none dies, will
+produce one hundred million in the course of five generations. In the last
+broods of the fall, males and females appear and fertile eggs are produced
+which lie dormant through the winter to start the cycle of the next year.
+Again, the eggs of some kinds of animals which normally have to unite with
+a male germ before they develop, can be made to develop by merely treating
+them with chemical solutions. The difference between an offspring derived
+in such a manner, and one which has developed from an egg fertilized by
+the male is that it is made up of characteristics from only one source,
+the maternal.
+
+=Dual Ancestry an Aid in Studying Heredity.--=Although we have the factors
+of heredity in a more simplified form in the case of asexual
+transmission, as a matter of fact most of our insight into the problems
+of heredity has been attained from a study of sexually reproducing forms,
+because the very existence of two sets of more or less parallel features
+offers a kind of checking up system by which we can follow a given
+characteristic.
+
+=Reversion.--=Occasionally, however, plants and animals do not develop the
+complete individuality we might expect, but stop short at or re-attain
+some ancestral stage along the line of descent, and thus come to resemble
+some progenitor perhaps many generations back of their own time. Thus it
+is well known that as regards one or more characteristics a child may
+resemble a grandparent or often some remote ancestor much more closely
+than it does its immediate parent. The reappearance of such ancestral
+traits the student of heredity designates as _Reversion_ or _Atavism_.
+
+Reversion may occur apparently in any class of plants or animals. It is
+especially pronounced among domesticated forms, which through man's
+selection have been produced under more or less artificial conditions. For
+example, among fancy breeds of pigeons, there may be an occasional return
+to the old slaty blue color of the ancestral rock-pigeon, with two dark
+cross-bars on the wings, from which all modern breeds have been derived.
+This is almost sure to happen if the fancy varieties are inter-crossed for
+two or three generations. Another example of reversion frequently cited is
+the occasional reappearance in domestic poultry of the reddish or brownish
+color pattern of the ancestral jungle-fowl to which, among modern forms,
+the Indian game seems most nearly related in color. Still another example
+is the cross-bars or stripes occasionally to be seen on the forelegs of
+colts, particularly mules, reminiscent of the extinct wild progenitors
+which were supposedly striped.
+
+Fig. 1, p. 9, is a picture of a hybrid between the common fowl and the
+guinea-fowl. The chevron-like markings on certain feathers show a
+reversion to a type of color pattern that is prevalent among both the
+primitive pheasants (the domestic chicken is a pheasant) and the primitive
+guinea-fowls. Although the common spotted guinea-fowl may be crossed with
+a black chicken which shows no trace of barring, nevertheless the hybrid
+offspring are likely to bear a chevron-like pattern such as that shown in
+the picture.
+
+There has been much quibbling over the relative meanings of reversion and
+atavism. The general idea, whichever term we use, is that there is a
+"throwing back" in a noticeable degree through inheritance to some
+ancestral condition beyond the immediate parents. A few recent authors
+have taken the term atavism in a restricted sense and use it to signify
+specifically those not uncommon cases in which a particular character of
+an offspring resembles the corresponding character of a grandparent
+instead of a parent. Such, for example, as the blue eye-color of a child
+with brown-eyed parents, each of whom in turn has had a blue-eyed parent.
+The tendency of other authors is to abandon the term entirely because of
+the diversity of meaning that has been attached to it in the past.
+
+
+[Illustration: FIG. 1
+
+Hybrid between the guinea-fowl and the common fowl, showing in many
+feathers reversion to a primitive chevron-like barring.]
+
+
+Certain classes of so-called reversions, such as the case of the eye-color
+just cited, are readily explicable on Mendelian principles as we shall see
+in a later chapter, but probably not all kinds of phenomena described as
+reversion can be so explained. For example, some seem to be cases of
+suppressed development. The word reversion, indeed, must be looked on as
+a convenient descriptive term rather than as the name of a single specific
+condition.
+
+=Telegony.--=There is yet a wide-spread belief in the supposed influence
+of an earlier sire on offspring born by the same mother to a later and
+different sire. This alleged phenomenon is termed _telegony_. For example,
+many dog-breeders assert that if a thoroughbred bitch has ever had pups by
+a mongrel father, her later offspring, although sired by a thoroughbred,
+will show taints of the former mongrel mating. In such cases the female is
+believed to be ruined for breeding purposes. Other supposed instances of
+such influences have been cited among horses, cattle, sheep, pigs, cats,
+birds, pets of various kinds and even men. The historic case most
+frequently quoted is that of Lord Morton's mare which bore a hybrid colt
+when bred to a quagga, a striped zebra-like animal now extinct. In later
+years the same mare bore two colts, sired by a black Arabian horse. Both
+colts showed stripes on the neck and other parts of the body, particularly
+on the legs. It was inferred that this striping was a sort of after effect
+of the earlier breeding with the quagga. In recent times, however,
+Professor Ewart has repeated the experiment a number of times with
+different mares using a Burchell zebra as the test sire. Although his
+experiments have been devised so as to conduce in every way possible to
+telegony his results have been negative. Moreover, it has been pointed out
+that the stripes on the legs of the two foals alleged to show telegony
+could not have been derived from the quagga sire for, unlike zebras,
+quaggas did not have their legs striped. Furthermore it is known that the
+occurrence of dark brown stripes on the neck, withers and legs of ordinary
+colts is not uncommon, some cases of which have exhibited more zebra-like
+markings than those of the colts from Lord Morton's mare. It seems much
+more probable, therefore, that the alleged instances are merely cases of
+ordinary reversion to the striped ancestral color pattern which probably
+characterized the wild progenitors of the domesticated horse.
+
+Various experiments on guinea-pigs, horses, mice and other forms,
+especially devised to test out this alleged after-influence of an earlier
+sire, have all proved negative and the general belief of the biologist
+to-day is that telegony is a myth.
+
+=Prenatal Influences Apart from Heredity.--=In discussing the problems of
+heredity it is necessary to consider also the possibilities of external
+influences apart from lineage which may affect offspring through either
+parent. Although modifications derived directly by the parent, and
+prenatal influences in general, are of extremely doubtful value as of
+permanent inheritable significance, nevertheless they must be reckoned
+with in any inventory of a child's endowment at birth. Impaired vitality
+on the part of the mother, bad nutrition and physical vicissitudes of
+various kinds all enter as factors in the birthright of the child, who,
+moreover, may bear in its veins slumbering poisons from some progenitor
+who has handed on blood taints not properly attributable to heredity. Of
+such importance is this kind of influence to the welfare of the immediate
+child that it will be necessary to discuss it in considerable detail in a
+later chapter.
+
+=Parent Body and Germ Not Identical.--=Inasmuch as each new individual
+appears to arise from material derived from its parent, taking the
+evidence at its face value one might suppose that any peculiarity of
+organization called forth in the living substance of the parent would
+naturally be repeated in the offspring, but a closer study of the
+developing organism from its first inception to maturity shows this to be
+probably a wrong conclusion. The parent-body and the reproductive
+substance contained in that body are by no means identical. It becomes an
+important question to decide, in fact, how much effect, if any, either
+permanent or temporary, the parent-body really has on the germ.
+
+A given fertile germ (Fig. 2, p. 13) gives rise by a succession of
+divisions to a body which we call the individual, but such a germ also
+gives rise to a series of new germ-cells which reside in that individual,
+and it is these germ-cells, not something derived from the body, that pass
+on the determiners of distinguishing features or qualities from generation
+to generation. It is only by grasping the significance of this fact that
+we can understand how in certain cases a totally different set of
+characters may appear in an offspring than those manifested in either
+parent.
+
+=An Hereditary Character Defined.--=By a _character_, in discussions in
+heredity, is meant simply a trait, feature or other characteristic of an
+organism. Where we can pick out a single definable characteristic which
+acts as a unit in heredity, for greater accuracy we term it a
+_unit-character_. Many traits are known to be inherited on a unit basis or
+are capable of being analyzed into factors which are so inherited. These
+unit-characters are in large measure inherited independently of one
+another apparently, although cases of characters inherited as a unit along
+with other characters are known.
+
+=Hereditary Mingling a Mosaic Rather Than a Blend.--=The independence of
+unit-characters in inheritance leads us to the important conclusion that
+the mingling of two lines of ancestry into a new individual is in no sense
+bringing them into the "melting pot," as it has been picturesquely
+expressed, but it is rather to be regarded as the mingling of two mosaics,
+each particle of which retains its own individuality, and which, even if
+overshadowed in a given generation, may nevertheless manifest its
+qualities undimmed in later generations when conditions favorable to its
+expression transpire.
+
+
+[Illustration: FIG. 2
+
+Diagram illustrating germinal continuity. Through a series of divisions a
+germ-cell gives rise to a body or a soma and to new germ-cells. The
+latter, not the body, give rise in turn to the next generation.]
+
+
+=Determiners of Characters, Not Characters Themselves, Transmitted.--=The
+fact should be thoroughly understood that the actual thing which is
+transmitted by means of the germ in inheritance is not the character
+itself, but something which will _determine_ the character in the
+offspring. It is important to remember this, for often these
+_determiners_, as they are called, may lie unexpressed for one or more
+generations and may become manifest only in later descendants. The truth
+of the matter is, the child does not inherit its characters from
+corresponding characters in the parent-body, but parent and child are
+alike because they are both products of the same line of germ-plasm, both
+are chips from the same old block.
+
+
+METHODS OF STUDYING HEREDITY
+
+Before entering into details it will be well to get some idea of the
+methods which are commonly employed in arriving at conclusions in the
+field of heredity. Some of these are extremely complex and all that we can
+do in an elementary presentation is to get a glimpse of the procedures.
+
+=Our Knowledge of Heredity Derived Along Three Lines.--=Our modern
+conceptions of heredity have been derived mainly from three distinct lines
+of investigation: First, from the study of embryology, in which the
+biologist concerns himself with the genesis of the various parts of the
+individual, and the mechanism of the germs which convey the actual
+materials from which these parts spring; second, through experimental
+breeding of plants and animals to compare particular traits or features in
+successive generations; and third, through the statistical treatment of
+observations or measurements of a large number of parents and their
+offspring with reference to a given characteristic in order to determine
+the average extent of resemblance between parents and children in that
+particular respect.
+
+=The Method of Experimental Breeding.--=A tremendous impetus was given to
+the method of experimental breeding when it was realized that we can
+itemize many of the parts or traits of an organism into entities which are
+inherited independently one of another. Such traits, or as we have already
+termed them, unit-characters, may be not only independently heritable but
+independently variable as well. The experimental method seeks to isolate
+and trace through successive generations the separate factors which
+determine the individual unit-characters of the organism. In this attempt
+cross-breeding is resorted to. Forms which differ in one or more respects
+are mated and the progeny studied. Next these offspring are mated with
+others of their own kind or mated back with the respective parent types.
+In this way the behavior of a particular character may often be followed
+and the germinal constitutions of the individuals concerned can be
+formulated with reference to it. Inasmuch as we shall give much
+consideration to this method in the chapter on Mendelism we need not
+consider it further here.
+
+=The Statistical Method.--=The statistical method seeks to obtain large
+bodies of facts and to deal with evidence as it appears through
+mathematical analysis of these facts. The attempt of its followers is to
+treat quantitatively all biological processes with which it is concerned.
+Historically Sir Francis Galton was the first to make any considerable
+application of statistical methods to the problems of heredity and
+variation. In his attempts to determine the extent of resemblance between
+relatives of different degree as regards bodily, mental and temperamental
+traits, he devised new methods of statistical analysis which constitute
+the basis of modern statistical biology, or _biometry_ as it is termed by
+its votaries. Professor Karl Pearson in particular has extended and
+perfected the mathematical methods of this field and stands to-day as
+perhaps its most representative exponent. The system is in the main based
+on the calculus of probability. The methods often are highly specialized,
+requiring the use of higher mathematics, and are therefore only at the
+command of specially trained workers.
+
+Just as insurance companies can tell us the probable length of human life
+in a given social group, since although uncertain in any particular case,
+it is reducible in mass to a predictable constant, so the biometrician
+with even greater precision because of his improved methods can often,
+when a large number of cases are concerned, give us the intensity of
+ancestral influence with reference to particular characters.
+
+For example, it is clear that by measuring a large number of adult human
+beings one can compute the average height or determine the height which
+will fit the greatest number. There will be some individuals below and
+some above it, but the greater the divergence from this standard height
+the fewer will be the individuals concerned.
+
+Galton compared the heights of 204 normal English parents and their 928
+adult offspring. In order to equalize the measurements of men and women he
+found he had to multiply each female height by 1.08. Then, to take both
+parents into account when comparing height of parents to that of children
+he added the height of the father to the proportionately augmented height
+of the mother and divided by two, thus securing the height of what he
+termed the "mid-parent." He found that the mid-parental heights of his
+subjects ranged from 64.5 to 72.5 inches, and that the general _mode_ was
+about 68.5 inches. It should be mentioned that the _mode_, in a given
+population, represents the group containing the largest number of
+individuals of one kind; it may or may not coincide with the average. The
+children of all mid-parents having a given height were measured next and
+tabulated with reference to these mid-parents. The results of Galton's
+measurements may be expressed simply as follows:
+
+  -----------------------------------------------------------------
+                                          |MODE|
+  ----------------------------------------|----|-------------------
+  Height of mid-parent|    |    |    |    |    |    |    |    |
+  in inches           |64.5|65.5|66.5|67.5|68.5|69.5|70.5|71.5|72.5
+                      |    |    |    |    |    |    |    |    |
+  Average height of   |    |    |    |    |    |    |    |    |
+  offspring           |65.8|66.7|67.2|67.6|68.3|68.9|69.5|69.9|72.2
+  -----------------------------------------------------------------
+
+=The Law of Regression.--=It is plain from this table that the offspring
+of short mid-parents tend to be under average or modal height though not
+so far below as their parents. Likewise children of tall parents tend to
+be tall but less tall than their parents. This fact illustrates what is
+known as Galton's _law of regression_; namely, that if parents in a given
+population diverge a certain amount from the mode of the population as a
+whole, their children, while tending to resemble them, will diverge less
+from this mode. It is clear that the extent of regression is an inverse
+measure of the intensity of inheritance from the immediate parents; if the
+deviation of the offspring from the general mode were nearly as great as
+that of their parents then the intensity of the inheritance must be high;
+if but slight--that is, if the offspring regressed nearly to the
+mode--then the intensity of the inheritance must be ranked as low. In the
+example in question it must be ranked as relatively high. Computations
+show that as regards stature the fraction two-thirds represents
+approximately the amount of resemblance between the two generations where
+both parents are considered.
+
+=Correlations Between Parents and Offspring.--=In modern researches the
+conception of mid-parent and mid-grandparent as utilized by Galton has
+been largely abandoned. It has been found more convenient as well as more
+accurate to keep the measurements of the two parents separate and to deal
+with correlations between fathers and sons, fathers and daughters, mothers
+and sons, mothers and daughters, brother and brother, etc. Professor
+Pearson and his pupils have found for a number of characters that the
+correlation between either parent and children, whether sons or daughters,
+is relatively close. The correlation between brother and brother, sister
+and sister, and brother and sister, usually ranges a little higher than
+the corresponding relation between parents and children.
+
+=The Biometrical Method, Statistical, Not Physiological.--=While biometry
+may in certain cases go far toward showing us the average intensity of
+the inheritance of certain characters it can not replace the method of
+the experimental breeder which deals with particular characters in
+individual pedigrees. It must be borne in mind that the biometrical method
+is a statistical and not a physiological one and that it is applicable
+only when large numbers of individuals are considered in mass. It is most
+valuable in cases where we are unable sharply to define single characters,
+due probably to the concurrent action of a number of independent causes,
+or where experiment is impossible so that we have to depend solely on
+numerical data gained by observation.
+
+=Mental Qualities Inheritable.--=Galton showed by this method long ago,
+and Pearson and his school have extended and more clearly established the
+work, that exceptional mental qualities tend to be inherited. While on the
+average the children of exceptional parents tend to be less exceptional
+than their parents, still they are far more likely to be exceptional than
+are the children of average parents. By this method Professor Pearson has
+shown that such mental and temperamental attributes as ability, vivacity,
+conscientiousness, temper, popularity, handwriting, etc., are as
+essentially determined as are physical features through the hereditary
+endowment.
+
+
+
+
+CHAPTER II
+
+THE BEARERS OF THE HERITAGE
+
+
+Before we can make any detailed analysis of the inheritance of characters
+we should have some general idea of the physical structure of animals and
+particularly some familiarity with the development of an individual from
+the egg, as well as some knowledge of the nature of the germ-cells.
+
+=The Cell the Unit of Structure.--=If we examine one of the higher
+animals, as, for example, the horse, the dog, or man, we find that it is
+made up of a large number of constituents, such as bones, muscles, nervous
+elements, blood and other tissues. Each kind of tissue is composed of a
+number of living units, ordinarily microscopic in size, which are known as
+cells. A careful examination of various cells reveals that although they
+may differ greatly in size, shape and minor details, they all alike
+possess certain well-marked characteristics. Each when reduced to its
+fundamental form is seen to consist of a small mass of living matter
+termed protoplasm in which may usually be distinguished two regions--the
+cell-body or _cytoplasm_, and the _nucleus_ (Fig. 3, p. 21). Any cell,
+whether it be of the brain, of the liver, or from any organ of an animal
+or plant, has this same fundamental structure. In addition, a limiting
+membrane or wall of some kind is generally present, although it is not a
+necessary constituent of all cells.
+
+
+[Illustration: FIG. 3
+
+Diagram of a cell showing various parts.]
+
+
+=Unicellular Organisms.--=While such a structure as a tree or a horse is
+composed of countless millions of cells, on the other hand numerous
+organisms, both plant and animal, exist which consist of only one cell.
+Yet this cell is just as characteristically a cell as are the components
+of a complex animal or plant. It has the necessary parts, the cell body
+and the nucleus. Moreover it exhibits all of the fundamental activities of
+life, though in a simplified form, that a complex higher organism does.
+
+=Importance of Cell-Theory.--=This discovery that every living thing is a
+single cell or an aggregation of cooperating cells and cell-products is
+one of our most important biological generalizations because it has
+brought such a wide range of phenomena under a common point of view. In
+the first place, the structure of both plants and animals is reducible to
+a common fundamental unit of organization. Moreover, both physiological
+and pathological phenomena are more readily understood since we recognize
+that the functions of the body in health or disease are in large measure
+the result of the activities of the individual cells of the functioning
+part. Then again, the problems of embryological development have become
+much more sharply defined since it could be shown that the egg is a single
+cell and that it is through a series of divisions of this cell and
+subsequent changes in the new cells thus formed that the new organism is
+built up. And lastly, the problem of hereditary transmission has been
+rendered more definite and approachable by the discovery that the male
+germ is likewise a single cell, that fertilization of the egg is therefore
+the union of two cells, and that in consequence the mechanism of
+inheritance must be stowed away somehow in these two cells.
+
+=Heredity in Unicellular Forms.--=In unicellular animals one can readily
+see how it is possible for an individual always to give rise to its own
+kind. One of the simplest of the single-celled animals is the _Ameba_
+(Fig. 4, p. 24).
+
+The ameba eats and grows as do other animals. Sooner or later it reaches a
+size beyond which it can not increase advantageously, yet it is
+continuously taking in new food material which stimulates it to further
+growth. Here then is a problem. The ameba solves this difficulty by
+dividing to form two amebæ. Such a division is illustrated in Fig. 4, p.
+24. First the nucleus divides, then the cell-body. When the two new amebæ
+separate completely each renews the occupation of eating and growing. But
+what has become of the parent? Here, where once existed a large adult
+ameba are two young amebæ. The parent individual as such has disappeared,
+yet there has been no death, for we have simply two bits of living jelly
+in place of one. They will in turn repeat the same process, so will their
+offspring, and thus, barring accident, this growth and reproduction, or
+overgrowth as we may regard it, may go on forever, as far as we know. Here
+the problem of heredity, or the resemblance of offspring to parent, is not
+a very complicated one. The substance of the cell-body and cell-nucleus
+divides into two similar halves, so that each descendant has the substance
+of the parent in its own body, only it has but half as much. It differs
+from the parent, not in quality or kind, but in size.
+
+
+[Illustration: FIG. 4
+
+Six successive stages in the division of _Ameba polypodia_ (after
+Schulze). The nucleus is seen as a dark spot in the interior.]
+
+
+=Reproduction and Heredity in Colonial Protozoa.--=There are enormous
+numbers of these single-celled animals existing in all parts of the world.
+Some are simple like the ameba, others are very complex in structure.
+Many, after division, move apart and pursue wholly independent courses of
+existence. On the other hand we find a modification appearing in some
+which is of the greatest importance. After division instead of moving
+apart the two cells may remain side by side and divide further to form
+two more, these in turn may divide and thus the process goes on until
+there is formed what is known as a colony. Each cell of such a colony
+resembles the original ancestral cell because each is a part of the actual
+substance of that cell. As in the ameba, the first two cells are the
+ancestral cell done up in two separate packets, and thus finally the full
+quota of cells must be so many separate packets of the same kind of
+material. Inasmuch as each is but a repetition of its original ancestor,
+it can, and at times does, produce a colony of the same kind as that
+ancestor produced.
+
+=Conjugation.--=At longer or shorter intervals, however, we find that two
+individuals, on the disruption of the old colony, instead of continuing
+the routine of establishing new colonies through a series of cell
+divisions, very radically alter their behavior. They unite and fuse into a
+single larger individual. This process is called _conjugation_. We find it
+occurring even in some species of ameba. The conjugating cells in some
+colonies are alike in size and appearance, in others different.
+
+=Specialization of Sex-Cells.--=A beautiful sphere-shaped colony known as
+_Volvox_ is to be found occasionally in roadside pools. Depending on the
+species of _Volvox_ to which it belongs, the colony may be made up of from
+a few hundred to several thousand individuals arranged in a single layer
+about the fluid-filled center of the sphere and bound together by a clear
+jelly-like inter-cellular substance. Each individual cell also connects
+with its neighbors by means of thin threads of living matter. One of the
+largest species is _Volvox globator_, one edge of which is represented in
+Fig. 5, p. 27. Mutual pressure of the cells gives them a polygonal shape
+when viewed from the surface. Each cell, with a few exceptions to be noted
+immediately, bears two long flagella, whip-like structures which project
+out into the water. The lashing of these flagella gives the ball a rotary
+motion and thus it moves about. When the colony has reached its adult
+condition and is ready to reproduce itself, certain cells without flagella
+and somewhat larger than the ordinary cells become more rounded in outline
+and increase considerably in size through the acquisition of food
+materials. They are then known as egg cells or ova. Each ovum finally
+enters on a series of cell-divisions forming a mass of smaller and smaller
+cells which gradually assumes the form of a hollow sphere like the parent
+colony. The young colonies thus formed drop into the interior of the
+parent colony to escape later to the outside as independent swimming
+organisms when the old colony dies and disintegrates.
+
+=The Fertilized Ovum Termed a Zygote.--=After a number of generations of
+such asexual reproduction, sexual reproduction occurs. The ova arise as
+usual. Certain members of the colony, on the other hand, go to the other
+extreme and divide up into bundles of from sixty-four to one hundred
+twenty-eight minute slender cells, each provided with flagella for
+locomotion. When mature these small flagellate cells, now known as
+_spermatozoa_, escape into the interior of the parent colony and swim
+about actively. Ultimately each ovum is penetrated by a spermatozoon, the
+two cells fuse completely and thus form the single _fertilized ovum_ or
+_zygote_. The body-cells of the mother colony finally disintegrate. After
+a period of rest each zygote, through a series of cell-divisions, develops
+into an adult Volvox. In some species of Volvox a still further advance is
+seen, in that instead of both kinds of gametes being produced in the same
+colony, the ova may be produced by one colony and the spermatozoa by
+another. Here, then, we have the foreshadowings of two sexes as separate
+individuals, a phenomenon of universal occurrence among the highest forms
+of animal life.
+
+
+[Illustration: FIG. 5
+
+_Volvox globator_ (from Hegner after Oltmanns). Half of a sexually
+reproducing colony: _o_, eggs; _s_, spermatozoa.]
+
+
+=Advancement Seen in the Volvox Colony.--=In the Volvox colony there is a
+distinct advance over the conditions met with in various lower protozoan
+colonies in that only certain individuals of the colony take part in the
+process of reproduction and these individuals are of two distinct types;
+one is a larger, food-laden cell or egg and the other a small, active,
+fertilizing cell. The motile forms are produced in much greater numbers
+than the eggs, plainly because they have to seek the egg and many will
+doubtless perish before this can be accomplished. This disparity in number
+is only a means of insuring fertilization of the egg. The remaining cells
+of the body carry on the ordinary activities of the colony such as
+locomotion and nutrition and have ceased to take any part in the
+production of new colonies.
+
+=Natural Death Appears With the Establishment of a Body Distinct from the
+Germ.--=Volvox is an organism of unusual interest because in it we see a
+prophecy of what is to come. Although still regarded as a colony of
+single-celled individuals, it represents in reality a transition between
+the whole group of unicellular animals termed protozoa and the many celled
+animals characterized by the possession of distinct tissues, known as
+_Metazoa_. Moreover, it shows an interesting stage in the establishment of
+a body or _soma_ distinct from special reproductive cells which have taken
+on the function of reproducing the colony. In such colonial forms natural
+death is found appearing for the first time, the reproductive cells alone
+continuing to perpetuate the species. Then again Volvox represents an
+important step in the establishment of sex in the animal kingdom for in
+its sexual reproduction the conjugating cells known as _gametes_ are no
+longer alike in appearance but have become differentiated into definite
+ova and spermatozoa.
+
+In Volvox as in the other organisms which we have studied we find that all
+of the cells including the germ-cells are produced by the repeated
+division of a parent cell, and consequently each must contain the
+characteristic living substance of that parent. Many other forms might be
+cited to illustrate reproduction in single-celled animals, whether free or
+in colonies, but all such cases would be practically but repetitions or
+modifications of those we have already examined.
+
+=Specialization in Higher Organisms.--=If we pass on to the higher animals
+and plants which are not single cells or colonies of similar cells but
+organisms made up of many different kinds of cells, we find a pronounced
+extension of the phenomenon met with in Volvox. Instead of each cell
+executing independently all of the life relations, certain ones are set
+apart for the performance of certain functions to the exclusion of other
+functions which are carried on by other members of the aggregation. Thus
+the organism as a whole has all the life relations carried on, but, as it
+were, by specialists.
+
+=Sexual Phenomena in Higher Forms.--=In the reproduction of multicellular
+organisms, one sees likewise but a continuation of the phenomena exhibited
+in Volvox. Ordinarily, each new form is produced by the successive
+divisions of a single germ-cell which in the vast majority of cases has
+conjugated with another germ-cell. In the development of the egg, as the
+divisions proceed, groups of cells become modified for their particular
+work until the entire organism is completed. During development certain
+cells are set apart for reproduction of the form just as they were in
+Volvox. These two kinds of reproductive cells in multicellular organisms
+are derived ordinarily from two separate individuals known as male and
+female, though there are some exceptions. The main difference between
+these cells which will have to unite to form a single fertile germ-cell,
+is that they have specialized in different directions; one is small and
+active, the other large, food-laden and passive. But with two such
+germ-cells coming as they do from two individuals, one the male, the other
+the female, it is obvious that the actual living substance of which each
+germ is composed will be distinctive of its own parental line and that
+when the germs unite these distinctive factors commingle, hence the
+complications of double ancestry arise.
+
+=Structure of the Cell.--=Before we can understand certain necessary
+details of the physical mechanism of inheritance we must inquire a little
+further into the finer structure of the cell and into the nature of cell
+division. A typical cell, as it would appear after treatment with various
+stains which bring out the different parts more distinctly, is shown in
+Fig. 3, p. 21. Typical, not that any particular kind of living cell
+resembles it very closely in appearance, but because it shows in a
+diagrammatic way the essential parts of a cell. In the diagram, there are
+two well-marked regions; a central _nucleus_ and a peripheral cell-body or
+_cytoplasm_. Other structures are pictured but only a few of them need
+command our attention at present. At one side of the nucleus one observes
+a small dot or granule surrounded by a denser area of cytoplasm. This body
+is called the _centrosome_. The nucleus in this instance is bounded by a
+well-marked nuclear membrane and within it are several substances. What
+appear to be threads of a faintly staining material, the _linin_, traverse
+it in every direction and form an apparent network. The parts on which we
+wish particularly to rivet our attention are the densely stained
+substances scattered along or embedded in the strands of this network in
+irregular granules and patches. This substance is called _chromatin_. It
+takes its name from the fact that it shows great affinity for certain
+stains and becomes intensely colored by them. This deeply colored portion
+of the cell, the chromatin, is by most biologists regarded as of great
+importance from the standpoint of heredity. One or more larger masses of
+chromatin or chromatin-like material, known as _chromatin nucleoli_, are
+often present, and not infrequently a small spheroidal body, differing in
+its staining reactions from the chromatin-nucleolus and sometimes called
+the _true nucleolus_, exists.
+
+=Cell-Division.--=In the simplest type of cell-division the nucleus first
+constricts in the middle, and finally the two halves separate. This
+separation is followed by a similar constriction and final division of the
+entire cell-body, which results in the production of two new cells. This
+form of cell-division is known as _simple_ or _direct division_. Such a
+simple division, while found in higher animals, is less frequent and
+apparently much less significant than another type of division which
+involves profound changes and rearrangements of the nuclear contents. The
+latter is termed _mitotic_ or _indirect_ cell-division. Fig. 6, p. 33,
+illustrates some of the stages which are passed through in indirect
+cell-division. The centrosome which lies passively at the side of the
+nucleus in the typical cell (Fig. 6_a_, p. 33) awakens to activity,
+divides and the two components come to lie at the ends of a fibrous
+spindle. In the meantime, the interior of the nucleus is undergoing a
+transformation. The granules and patches of chromatin begin to flow
+together along the nuclear network and become more and more crowded until
+they take on the appearance of one or more long deeply-stained threads
+wound back and forth in a loose skein in the nucleus (Fig. 6_b_, p. 33).
+If we examine this thread closely, in some forms it may be seen to consist
+of a series of deeply-stained chromatin granules packed closely together
+intermingled with the substance of the original nuclear network.
+
+As the preparations for division go on the coil in the nucleus breaks up
+into a number of segments which are designated as _chromosomes_ (Fig.
+6_c_, p. 33). The nuclear membrane disappears. The chromosomes and the
+spindle-fibers ultimately become related in such a way that the
+chromosomes come to lie at the equator of the spindle as shown in Fig
+6_d_, p. 33. Each chromosome splits lengthwise to form two daughter
+chromosomes which then diverge to pass to the poles of the spindle (Figs.
+6_e_ and _f_, p. 33). Thus each end of the spindle comes ultimately to be
+occupied by a set of chromosomes. Moreover each set is a duplicate of the
+other, because the substance of any individual chromosome in one group has
+its counterpart in the other. In fact this whole complicated system of
+indirect division is regarded by most biologists as a mechanism for
+bringing about the precise halving of the chromosomes.
+
+
+[Illustration: FIG. 6
+
+Diagram showing representative stages in mitotic or indirect
+cell-division: _a_, resting cell with reticular nucleus and single
+centrosome; _b_, the two new centrosomes formed by division of the old one
+are separating and the nucleus is in the spireme stage; _c_, the nuclear
+wall has disappeared, the spireme has broken up into six separate
+chromosomes, and the spindle is forming between the two centrosomes; _d_,
+equatorial plate stage in which the chromosomes occupy the equator of the
+spindle; _e_, _f_, each chromosome splits lengthwise and the daughter
+chromosomes thus formed approach their respective poles; _g_,
+reconstruction of the new nuclei and division of the cell body; _h_,
+cell-division completed.]
+
+
+The chromosomes of each group at the poles finally fuse and two new
+nuclei, each similar to the original one, are constructed (Figs. 6_g_ and
+_h_, p. 33). In the meantime a division of the cell-body is in progress
+which, when completed, results in the formation of two complete new cells.
+
+As all living matter if given suitable food, can convert it into living
+matter of its own kind, there is no difficulty in conceiving how the new
+cell or the chromatin material finally attains to the same bulk that was
+characteristic of the parent cell. In the case of the chromatin, indeed,
+it seems that there is at times a precocious doubling of the ordinary
+amount of material before the actual division occurs.
+
+=Chromosomes Constant in Number and Appearance.--=With some minor
+exceptions, to be noted later, which increase rather than detract from the
+significance of the facts, the chromosomes are always the same in number
+and appearance in all individuals of a given species of plants or animals.
+That is, every species has a fixed number which regularly recurs in all of
+its cell-divisions. Thus the ordinary cells of the rat, when preparing to
+divide, each display sixteen chromosomes, the frog or the mouse,
+twenty-four, the lily twenty-four, and the maw-worm of the horse only
+four. The chromosomes of different kinds of animals or plants may differ
+very much in appearance. In some they are spherical, in others rod-like,
+filamentous or perhaps of other forms. In some organisms the chromosomes
+of the same nucleus may differ from one another in size, shape and
+proportions, but if such differences appear at one division they appear at
+others, thus showing that in such cases the differences are constant from
+one generation to the next.
+
+=Significance of the Chromosomes.--=The question naturally arises as to
+what is the significance of the chromosomes. Why is the accurate
+adjustment which we have noted for their division necessary? The very
+existence of an elaborate mechanism so admirably adapted to their precise
+halving, predisposes one toward the belief that the chromosomes have an
+important function which necessitates the retention of their individuality
+and their equal division. Many biologists accept this along with other
+evidence as indicating that in chromatin we have a substance which is not
+the same throughout, that different regions of the same chromosome have
+different physiological values.
+
+When the cell prepares for divisions, the granules, as we have seen,
+arrange themselves serially into a definite number of strands which we
+have termed chromosomes. Judging from all available evidence, the granules
+are self-propagating units; that is, they can grow and reproduce
+themselves. So that what really happens in mitosis in the splitting of the
+chromosomes is a precise halving of the series of individual granules of
+which each chromosome is constituted, or in other words each granule has
+reproduced itself. Thus each of the two daughter cells presumably gets a
+sample of every kind of chromosomal particle, hence, the two cells are
+qualitatively alike. To use a homely illustration we may picture the
+individual chromosomes to ourselves as so many separate trains of freight
+cars, each car of which is loaded with different merchandise. Now, if
+every one of the trains could split along its entire length and the
+resulting halves each grow into a train similar to the original, so that
+instead of one there would exist two identical trains, we should have a
+phenomenon analogous to that of a dividing chromosome.
+
+=Cleavage of the Egg.--=It is through a series of such divisions as these
+that the zygote or fertilized egg-cell builds up the tissues and organs of
+the new organism. The process is technically spoken of as _cleavage_.
+Cleavage generally begins very shortly after fertilization. The fertile
+egg-cell divides into two, the resulting cells divide again and thus the
+process continues, with an ever-increasing number of cells.
+
+=Chief Processes Operative in Building the Body.--=Although of much
+interest, space will not permit of a discussion in detail of the building
+up of the special organs and tissues of the body. It must suffice merely
+to mention the four chief processes which are operative. These are, (1)
+infoldings and outfoldings of the various cell complexes; (2)
+multiplication of the component cells; (3) special changes (_histological
+differentiation_) in groups of cells; and (4) occasionally resorption of
+certain areas of parts.
+
+=The Origin of the New Germ-Cells.--=On account of the unusual importance
+from the standpoint of inheritance, which attaches to the germ-cells, a
+final word must be said about their origin in the embryo. While the
+evidence is conflicting in some cases, in others it has been well
+established that the germ-cells are set apart very early from the cells
+which are to differentiate into the ordinary body tissues. Fig. 7_A_, p.
+38, shows a section through the eight-celled stage of _Miastor_, a fly, in
+which a single large, primordial germ-cell (_p. g. c._) has already been
+set apart at one end of the developing embryo. The nuclei of the rest of
+the embryo still lie in a continuous protoplasmic mass which has not yet
+divided up into separate cells. The densely stained nuclei at the opposite
+end of the section are the remnants of nurse-cells which originally
+nourished the egg. Fig. 7_B_, p. 38, is a longitudinal section through a
+later stage in the development of _Miastor_; the primitive germ-cells
+(oög) are plainly visible. Still other striking examples might be cited.
+Even in vertebrates the germ-cells may often be detected at a very early
+period.
+
+=Significance of the Early Setting Apart of the Germ-Cells.--=It is of
+great importance for the reader to grasp the significance of this early
+setting apart of the germ-cells because so much in our future discussion
+hinges on this fact. The truth of the statement made in a previous chapter
+that the body of an individual and the reproductive substance in that body
+are not identical now becomes obvious. For in such cases as those just
+cited one sees the germinal substance which is to carry on the race set
+aside at an early period in a given individual; it takes no part in the
+formation of that individual's body, but remains a slumbering mass of
+potentialities which must bide its time to awaken into expression in a
+subsequent generation. Thus an egg does not develop into a body which in
+turn makes new germ-cells, but body and germ-cells are established at the
+same time, the body harboring and nourishing the germ-cells, but not
+generating them (Fig. 2, p. 13). The same must be true also in many cases
+where the earliest history of the germ-cells can not be visibly followed,
+because in any event, in all higher animals, they appear long before the
+embryo is mature and must therefore be descendants of the original
+egg-cell and not of the functioning tissues of the mature individual. This
+need not necessarily mean that the germ-cells have remained wholly
+unmodified or that they continue uninfluenced by the conditions which
+prevail in the body, especially in the nutritive blood and lymph stream,
+although as a matter of fact most biologists are extremely skeptical as to
+the probability that influences from the body beyond such general
+indefinite effects as might result from under-nutrition or from poisons
+carried in the blood, modify the intrinsic nature of the germinal
+substances to any measurable extent.
+
+
+[Illustration: FIG. 7
+
+A--Germ-cell (_p. g. c._) set apart in the eight-celled stage of cleavage
+in _Miastor americana_ (after Hegner). The walls of the remaining seven
+somatic cells have not yet formed though the resting or the dividing (_M
+p_) nuclei may be seen; _c R_, chromatin fragments cast off from the
+somatic cells.
+
+B--Section lengthwise of a later embryo of _Miastor_; the primordial
+egg-cells (_oög__{3}) are conspicuous (after Hegner).]
+
+
+=Germinal Continuity.--=The germ-cells are collectively termed the
+_germinal protoplasm_ and it is obvious that as long as any race continues
+to exist, although successive individuals die, some germinal protoplasm is
+handed on from generation to generation without interruption. This is
+known as the theory of _germinal continuity_. When the organism is ready
+to reproduce its kind the germ-cells awaken to activity, usually
+undergoing a period of multiplication to form more germ-cells before
+finally passing through a process of what is known at _maturation_, which
+makes them ready for fertilization. The maturation process proper, which
+consists typically of two rapidly succeeding divisions, is preceded by a
+marked growth in size of the individual cells.
+
+=Individuality of Chromosomes.--=Before we can understand fully the
+significance of the changes which go on during maturation we shall have to
+know more about the conditions which prevail among the chromosomes of
+cells. As already noted each kind of animal or plant has its own
+characteristic number and types of chromosomes when these appear for
+division by mitosis. In many organisms the chromosomes are so nearly of
+one size as to make it difficult or impossible to be sure of the identity
+of each individual chromosome, but on the other hand, there are some
+organisms known in which the chromosomes of a single nucleus are not of
+the same size and form (Fig. 8, p. 41). These latter cases enable us to
+determine some very significant facts. Where such differences of shape and
+proportion occur they are constant in each succeeding division so that
+similar chromosomes may be identified each time. Moreover, in all ordinary
+mitotic divisions where the conditions are accurately known, these
+chromosomes of different types are found to be present as pairs of similar
+elements; that is, there are two of each form or size.
+
+=Pairs of Similar Chromosomes in the Nucleus Because One Chromosome Comes
+from Each Parent.--=When we recall that the original fertilized egg from
+which the individual develops is really formed by the union of two
+gametes, ovum and spermatozoon, and that each gamete, being a true cell,
+must carry its own set of chromosomes, the significance of the pairs of
+similar chromosomes becomes evident; one of each kind has probably been
+contributed by each gamete. This means that the zygote or fertile ovum
+contains double the number of chromosomes possessed by either gamete, and
+that, moreover, each tissue-cell of the new individual will contain this
+dual number. For, as we have seen, the number of chromosomes is, with
+possibly a few exceptions, constant in the tissue-cells and early
+germ-cells in successive generations of individuals. For this to be true
+it is obvious that in some way the nuclei of the conjugating gametes have
+come to contain only half the usual number. Technically the tissue-cells
+are said to contain the _diploid_ number of chromosomes, the gametes the
+reduced or _haploid_ number.
+
+
+[Illustration: FIG. 8
+
+A--Chromosomes of the mosquito (_Culex_) after Stevens.
+
+B--Chromosomes of the fruit-fly (_Drosophila_) after Metz.
+
+Both of these forms have an unusually small number of chromosomes.]
+
+
+=In Maturation the Number of Chromosomes Is Reduced by One-Half.--=This
+halving, or as it is known, _reduction_ in the number of chromosomes is
+the essential feature of the process of maturation. It is accomplished by
+a modification in the mitotic division in which instead of each chromosome
+splitting lengthwise, as in ordinary mitosis, the chromosomes unite in
+pairs (Fig. 9_b_, p. 42), a process known technically as _synapsis_, and
+then apparently one member of each pair passes entire into one new
+daughter cell, the other member going to the other daughter cell (Fig.
+9_c_, p. 42). In the pairing preliminary to this _reduction division_,
+leaving out of account certain special cases to be considered later,
+according to the best evidence at our command the union always takes place
+between two chromosomes which match each other in size and appearance.
+Since one of these is believed to be of maternal and the other of
+paternal origin, the ensuing division separates corresponding mates and
+insures that each gamete gets one of each kind of chromosome although it
+appears to be a matter of mere chance whether or not a given cell gets the
+paternal or the maternal representative of that kind.
+
+
+[Illustration: FIG. 9
+
+Diagram to illustrate spermatogenesis: _a_, showing the diploid number of
+chromosomes (six is arbitrarily chosen) as they occur in divisions of
+ordinary cells and spermatogonia; _b_, the pairing (synapsis) of
+corresponding mates in the primary spermatocyte preparatory to reduction;
+_c_, each secondary spermatocyte receives three, the haploid number of
+chromosomes; _d_, division of the secondary spermatocytes to form _e_,
+spermatids, which transform into _f_, spermatozoa.]
+
+
+=Maturation of the Sperm-Cell.--=In the maturation of the male gamete the
+germ-cell, now known as a _spermatogonium_, increases greatly in size to
+become a _primary spermatocyte_. In each primary spermatocyte the pairing
+of the chromosomes already alluded to occurs as indicated in Fig. 9_b_, p.
+42, where six is taken arbitrarily to indicate the ordinary or _diploid_
+number of chromosomes, and three the reduced or _haploid_ number. The
+division of the primary spermatocyte gives rise to two _secondary
+spermatocytes_ (_c_), the paired chromosomes separating in such a way that
+a member of each pair goes to each secondary spermatocyte. Each secondary
+spermatocyte (_d_) soon divides again into two _spermatids_ (_e_), but in
+this second division the chromosomes each split lengthwise as in an
+ordinary division so that there is no further reduction. In some forms the
+reduction division occurs in the secondary spermatocytes instead of the
+primary. Each spermatid transforms into a mature spermatozoon (_f_). The
+spermatozoa of most animals are of linear form, each with a head, a
+middle-piece and a long vibratile tail which is used for locomotion. The
+head consists for the most part of the transformed nucleus and is
+consequently the part which bears the chromosomes.
+
+=Maturation of the Egg-Cell.--=As regards the behavior of the chromosomes
+the maturation of the ovum parallels that of the sperm-cell. There are not
+so many primordial germ-cells formed and only one out of four of the
+ultimate cells becomes a functional egg. As in maturation of the
+sperm-cell there is a growth period in which _oögonia_ enlarge to become
+_primary oöcytes_ (Fig. 10_b_, p. 45). In each primary oöcyte as in the
+primary spermatocyte the chromosomes pair and two rapidly succeeding
+divisions follow in one of which the typical numerical reduction in the
+chromosomes occurs. A peculiarity in the maturation of the ovum is that
+there is a very unequal division of the cytoplasm in cell division so that
+three of the resulting cells usually termed _polar bodies_ are very small
+and appear like minute buds on the side of the fourth or egg-cell proper.
+
+The scheme of this formation of the polar bodies is indicated in Fig. 10,
+p. 45. In Fig. 10_b_ the chromosomes are seen paired and ready for the
+first division; that is, for the formation of the first polar body. Figs.
+10_c_, _d_, p. 45, show the giving off of this body. Note that while only
+a small proportion of the cytoplasm passes into this tiny cell, its
+chromatin content is as great as that of the ovum. A second polar body
+(Figs. 10_e_, _f_, p. 45) is formed by the egg, but in this case each
+chromosome splits lengthwise, as in ordinary mitosis, and there is no
+further numerical reduction. In the meantime, typically, a third polar
+body is formed by division of the first. (Stages _e_, _f_, _g_.)
+
+=Parallel Between the Maturation of Sperm- and Egg-Cell.--=This rather
+complex procedure of the germ-cells will be rendered more intelligible
+through a careful study of Figs. 9 and 10, pp. 42 and 45, and Fig. 11, p.
+46, which indicates the parallel conditions in spermotogenesis and
+oögenesis.
+
+
+[Illustration: FIG. 10
+
+Diagram to illustrate oögenesis: _a_, showing the diploid number of
+chromosomes (six is arbitrarily chosen) as they occur in ordinary cells
+and oögonia; _b_, the pairing of corresponding mates preparatory to
+reduction; _c_, _d_, reduction division, giving off of first polar body;
+_e_, egg preparing to give off second polar body, first polar body ready
+for division; _f_, _g_, second polar body given off, division of first
+polar body completed. The egg nucleus, now known as the female pronucleus,
+and each body contain the reduced or haploid number of chromosomes.]
+
+
+The view now generally held regarding the polar bodies is that they are
+really abortive eggs. They later disappear, taking no part in
+embryo-formation. It can readily be seen how such an unequal division is
+advantageous to the large cell, for it receives all of the rich store of
+food material that would be distributed among the four cells if all were
+of equal size. This increased amount of food is a favorable provision for
+the forthcoming offspring whose nourishment is thus more thoroughly
+insured.
+
+
+[Illustration: FIG. 11
+
+Diagram showing the parallel between maturation of the sperm-cell and
+maturation of the ovum.]
+
+
+On the other hand, all of the sperm-cells develop into complete active
+forms, which, as aforesaid, usually become very much elongated and develop
+a motile organ of some kind. In such cells an accumulation of food to any
+large extent would hinder rather than help them, because it would
+seriously interfere with their activity.
+
+=Fertilization.--=In fertilization (Fig. 12, p. 48) the spermatozoon
+penetrates the wall of the ovum and after undergoing considerable
+alteration its nucleus fuses with the nucleus of the egg. In some forms
+only the head (nucleus) and middle-piece enter, the tail being cut off by
+a so-called fertilization membrane which forms at the surface of the egg
+and effectually blocks the entrance of other spermatozoa. Thus normally
+only one spermatozoon unites with an egg. In some forms while several may
+enter the egg only one becomes functional. As soon as the nucleus of the
+spermatozoon, now known as the male _pronucleus_, reaches the interior of
+the egg, it enlarges and becomes similar in appearance to the female
+_pronucleus_. It swings around in such a way (Fig. 12_b_, p. 48) that the
+middle piece, now transformed into a centrosome, lies between it and the
+female pronucleus. The two pronuclei (_c_, _d_, _e_), each containing the
+reduced number of chromosomes, approach, the centrosome divides, the
+nuclear walls disappear, the typical division spindle forms, and the
+chromosomes of paternal and maternal origin respectively come to lie side
+by side at the equator of the spindle ready for the first division or
+cleavage (_f_, _g_). It will be noted that the individual chromosomes do
+not intermingle their substance at this time, but that each apparently
+retains its own individuality. There is considerable evidence which
+indicates that throughout life the chromosomes contributed by the male
+parent remain distinct from those of the female parent. Inasmuch as each
+germ-cell, after maturation, contains only half the characteristic number
+of chromosomes, the original number is restored in fertilization.
+
+
+[Illustration: FIG. 12
+
+Diagram to illustrate fertilization; [male], male pronucleus; [female],
+female pronucleus; observe that the chromosomes of maternal and paternal
+origin respectively do not fuse.]
+
+
+=Significance of the Behavior of the Chromosomes.--=The question confronts
+us as to what is the significance of this elaborate system which keeps the
+chromosomes of constant size, shape and number; which partitions them so
+accurately in ordinary cell-divisions; and which provides for a reduction
+of their numbers by half in the germ-cell while yet securing that each
+mature gamete gets one of each kind of chromosome. Most biologists look on
+these facts as indicating that the chromosomes are specifically concerned
+in inheritance.
+
+In the first place it is recognized that as regards the definable
+characters which separate individuals of the same species, offspring may
+inherit equally from either parent. And it is a very significant fact that
+while the ovum and spermatozoon are very unequal in size themselves, the
+chromosomes of the two germ-cells are of the same size and number. This
+parity in chromosomal contribution points clearly to the means by which an
+equal number of character-determiners might be conveyed from each parent.
+Moreover it is mainly the nucleus of the sperm-cell in some organisms
+which enters the egg, hence the determiners from the male line must exist
+wholly or largely somewhere in the nucleus. And the bulk of the nucleus in
+the spermatozoon consists of the chromosomes or their products.
+
+=A Single Set of Chromosomes Derived from One Parent Only Is Sufficient
+for the Production of a Complete Organism.--=That a single or haploid set
+of chromosomes as seen in the gametes is sufficient contribution of
+chromatin for the production of a complete organism is proved by the fact
+that the unfertilized eggs of various animals (many echinoderms, worms,
+mollusks, and even the frog) may be artificially stimulated to development
+without uniting at all with a spermatozoon. The resulting individual is
+normal in every respect except that instead of the usual diploid number it
+has only the single or haploid number of chromosomes. Its inheritance of
+course is wholly of maternal origin. The converse experiment in
+echinoderms in which a nucleus of male origin (that is, a spermatozoon)
+has been introduced into an egg from which the original nucleus has been
+removed shows that the single set of chromosomes carried by the male
+gamete is also sufficient to cooperate with the egg-cytoplasm in
+developing a complete individual.
+
+=The Duality of the Body and the Singleness of the Germ.--=Since every
+maternal chromosome in the ordinary cell has an equivalent mate derived
+from the male parent, it follows therefore, supposing the chromosomes do
+have the significance in inheritance attributed to them, that as regards
+the measurable inheritable differences between two individuals, the
+ordinary organism produced through the union of the two germ-cells is,
+potentially at least, dual in nature. On the other hand through the
+process of reduction the gametes are provided with only a single set of
+such representatives. This duality of the body and singleness of the
+mature germ is one of the most striking facts that come to light in
+embryology. How well the facts fit in with the behavior of certain
+hereditary characters will be seen later in our discussions of Mendelism.
+
+=The Cytoplasm Not Negligible in Inheritance.--=Just what part is played
+by the cytoplasm in inheritance is not clear, but it is probably by no
+means a negligible one. The cytoplasm of a given organism is just as
+distinctive of the species or of the individual of which it forms a part
+as are the chromosomes. It is well established that neither nucleus nor
+cytoplasm can fully function or even exist long without the other, and
+neither can alone produce the other. They undoubtedly must cooperate in
+building up the new individual, and the cytoplasm of the new individual is
+predominantly of maternal origin. It is obvious that all of the more
+fundamental characters which make up an organism, such, for instance, as
+make it an animal of a certain order or family, as a human being or a dog
+or a horse, are common to both parents, and there is no way of measuring
+how much of this fundamental constitution comes from either parent, since
+only closely related forms will interbreed. In some forms, moreover, the
+broader fundamental features of embryogeny are already established before
+the entrance of the spermatozoon. It is probable therefore that instead of
+asserting that the entire quota of characters which go to make up a
+complete individual are inherited from each parent equally, we are
+justified only in maintaining that this equality is restricted to those
+measurable differences which veneer or top off, as it were, the
+individual. We may infer that in the development of the new being the
+chromosomes of the egg together with those derived from the male work
+jointly on or with the other germinal contents which are mostly
+cytoplasmic materials of maternal origin.
+
+=The Chromosomes Possibly Responsible for the Distinctiveness of Given
+Characters.--=It seems probable that in the establishment of certain basic
+features of the organism the cooperation of the cytoplasm with chromatin
+of either maternal or paternal origin might accomplish the same end, but
+that certain distinctive touches are added or come cumulatively into
+expression through influences carried, predominantly at least, in the
+chromatin from one as against the other parent. These last distinctive
+characters of the plant or animal constitute the individual differences of
+such organisms. In this connection it is a significant fact that in young
+hybrids between two distinct species the early stages of development,
+especially as regards symmetry and regional specifications, are
+exclusively or predominantly maternal in character, but the male influence
+becomes more and more apparent as development progresses until the final
+degree of intermediacy is attained.
+
+From the evidence at hand this much seems sure, that the paternal and
+maternal chromosomes respectively carry substances, be they ferments,
+nutritive materials or what not, that are instrumental in giving the final
+parity of personal characters which we observe to be equally heritable
+from either line of ancestry. It is clear that most of the characters of
+an adult organism can not be merely the outcome of any unitary substance
+of the germ. Each is the product of many cooperating factors and for the
+final outcome any one cooperant is probably just as important in its way
+as any other. The individual characters which we juggle to and fro in our
+breeding experiments seem apexed, as it were, on more fundamental features
+of organic chemical constitution, polarity, regional differentiation, and
+physiological balance, but since such individual characters parallel so
+closely the visible segregations and associations which go on among the
+chromosomes of the germ-cells it would seem that they, at least, are
+represented in the chromosomes by distinctive cooperants which give the
+final touch of specificity to those hereditary characters which can be
+shifted about as units of inheritance.
+
+=Sex and Heredity.--=Whatever the origin of fertilization may have been in
+the world of life, or whatever its earliest significance, the important
+fact remains that to-day it is unquestionably of very great significance
+in relation to the phenomena of heredity. For in all higher animals, at
+least, offspring may possess some of the characteristics originally
+present in either of two lines of ancestry, and this commingling of such
+possessions is possible only through sexual reproduction. As has already
+been seen, in the pairing of chromosomes previous to reduction, the
+corresponding members of a pair always come together so that in the final
+segregation each gamete is sure to have one of each kind although whether
+a given chromosome of the haploid set is of maternal or paternal origin
+seems to be merely a matter of chance. Thus, for instance, if we
+arbitrarily represent the chromosomes of a given individual by _ABC_
+_abc_, and regard _A_, _B_ and _C_ as of paternal and _a_, _b_ and _c_ as
+of maternal origin, then in synapsis only _A_ and _a_ can pair together,
+_B_ and _b_ and _C_ and _c_, but each pair operates independently of the
+other so that in the ensuing reduction division either member of a pair
+may get into a cell with either member of the other pairs. That is, the
+line up for division at a given reduction might be any one of the
+following, ABC/abc ABc/abC Abc/aBC AbC/aBc. This would yield the following
+eight kinds of gametes, _ABC_, _abc_, _ABc_, _abC_, _Abc_, _aBC_, _AbC_,
+_aBc_, each bearing one of each kind of chromosome required to cover the
+entire field of characters necessary to a complete organism. And since
+each sex would be equally likely to have these eight types of gametes and
+any one of the eight in one individual might meet any one of the eight of
+the other, the possible number of combinations in the production of a new
+individual from such germ-cells would be 8x8, or 64. With the larger
+numbers of chromosomes which exist in most animals it is readily seen that
+the number of possible combinations becomes very great. Thus any
+individual of a species with twenty chromosomes--and many animals,
+including man, have more--would have ten pairs at the reduction period and
+could therefore form (2)^{10}, or 1,024 different gametes in each sex. And
+since any one of these in one sex would have an equal chance of meeting
+with any one in the opposite sex, the total number of possible different
+zygotes that might be produced would be (1,024)^{2}, or 1,048,576. Sex
+therefore, through recombinations of ancestral materials, undoubtedly
+means, among other things, the production of great diversity in
+offspring.
+
+
+DETERMINATION OF SEX
+
+=Many Theories.--=From earliest times the problem of sex determination has
+been one of keen interest, and needless to say hundreds of theories have
+been propounded to explain it. Geddes and Thomson say that Drelincourt
+recorded two hundred sixty-two so-called theories of sex production and
+remark that since his time the number has at least been doubled. The
+desirability of controlling sex has naturally appealed strongly to
+breeders of domesticated animals.
+
+A study of animals born in litters, or of twins, is enough in itself to
+make us skeptical of theories of sex-determination based on nutritional or
+external factors. In a litter of puppies, for example, there are usually
+both males and females, although in their prenatal existence they have all
+been subject to the same nutritional and environmental conditions.
+Likewise in ordinary human twins one may be a boy, the other a girl,
+whereas if the nutritional condition of the mother were the fact
+determining sex, both should be boys or both girls. However, there are
+twins known as _identical twins_ who are remarkably alike and who are
+always of the same sex. But there is reason to suppose that identical
+twins in reality come from the same zygote. Presumably in early
+embryogeny, probably at the two-celled stage of cleavage, the two
+blastomeres become separated and each gives rise to a complete individual
+instead of only the half of one it would have produced had the two
+blastomeres remained together. Such twins are monochorial; that is, they
+grow inside the same fetal membrane, whereas each ordinary twin has its
+own fetal membrane and has obviously originated from a separate ovum. It
+has been established experimentally in several kinds of animals that early
+cleavage blastomeres when isolated can each develop into a complete
+individual. In man, ordinary twins are no more alike than ordinary
+brothers and sisters, but identical twins are strikingly similar in
+structure, appearance, habits, tastes, and even susceptibility to various
+maladies. The fact that they are invariably of the same sex is a strong
+reason for believing that sex was already developed in the fertile ovum
+and consequently in the resulting blastomeres from that ovum.
+
+The young of the nine-banded armadillo in a given litter are invariably of
+the same sex and are closely similar in all features. Newman and Patterson
+have shown that all the members of a litter come from the same egg.
+Patterson has established the fact that cleavage of the egg takes place in
+the usual manner, but later separate centers of development appear in the
+early embryonic mass and give rise to the separate young individuals.
+
+Again in certain insects where one egg indirectly gives rise to a chain of
+embryos, or to a number of separate larvæ, possibly as many as a thousand,
+all of the latter are of the same sex. Even in some plants researches have
+shown that sex is already determined at the beginning of development.
+Then, too, much evidence has come to light recently showing that
+sex-characters in certain cases behave as heritable characters and are
+independent of external conditions. Lastly there is visible and convincing
+evidence obtainable through microscopical observations that sex is
+determined by a mechanism in the germ-cells themselves. It is chiefly to
+these latter facts that I wish to direct attention for the present.
+
+=The Sex Chromosome.--=The evidence centers about a special chromosome or
+chromosome-group commonly designated as the _sex-chromosome_ or
+_X-element_, which has been found in various species of animals, including
+man. In the males of such animals this chromosome is present in addition
+to the regular number of pairs, thus giving rise to an _uneven_ instead of
+the conventional even number of chromosomes. This element remains
+undivided in one of the maturation divisions of the spermatocytes, in some
+forms in the first in others in the second, and passes entire to one pole
+of the spindle (Fig. 13, p. 58). This results in the production of two
+classes of cells, one containing the _X_-element and one not. The outcome
+is that two corresponding classes of spermatozoa are produced. The
+phenomena involved are diagrammatically represented in Fig. 13. It has
+been clearly demonstrated in several cases that eggs fertilized by
+spermatozoa which possess this _X_-element, always become females, those
+fertilized by spermatozoa which do not possess it always develop into
+males.
+
+
+[Illustration: FIG. 13
+
+Diagram illustrating the behavior of the _x_-element or sex-chromosome in
+the maturation of the sperm-cell. In one of the two maturation divisions
+(represented here as in the first) it passes undivided to one pole (_a_,
+_b_, _c_), in the other it divides. Since the cell without the _x_-element
+also divides the result is that ultimately from the original primary
+spermatocyte (_a_) four cells are formed (_f_), two with the _x_-element
+and two without it. Half of the spermatozoa therefore will bear an
+_x_-element, half will be without it. In _a_ the ordinary chromosomes,
+arbitrarily indicated as 10, are supposed to have already paired for
+reduction so that the original diploid number in spermatogonia and
+body-cells of the male would be 20 plus the _x_-chromosome.]
+
+
+It has been found, furthermore, that in species in which the males possess
+this extra element the females have two of them. That is, if the original
+number in the somatic cells of the male were twenty-three, twenty-two
+ordinary and one _X_-element, the number in the somatic cells of the
+female would be twenty-four, or twenty-two ordinary and two _X_-elements.
+It has been found that when the chromosomes of the female pair for the
+reduction division, each chromosome uniting with its corresponding fellow,
+the two _X_-elements in the female pair in the usual way so that every
+egg-cell possesses an _X_-element. Thus every mature egg has an
+_X_-element, while only half of the spermatozoa have one. That is, if we
+assume twenty-three as the diploid number present originally in the
+somatic cells of the male and twenty-four as the number in the female,
+then one-half the spermatozoa of the male would contain the haploid number
+eleven, and the other half, the number twelve, whereas every mature ovum
+would contain twelve. Since there are equal numbers of the spermatozoa
+with the _X_-element and without it, and inasmuch as presumably under
+ordinary conditions one kind is as likely to fertilize the egg as the
+other, then there are equal chances at fertilization of producing a zygote
+with two _X_-elements or with but one.
+
+  Thus, Spermatozoon + _X_ by Ovum + _X_ = Zygote + _XX_.
+        Spermatozoon (no _X_) by Ovum + _X_ = Zygote + _X_.
+
+We have already seen that the former is always female, the latter male. It
+thus becomes possible to distinguish the sex of an embryo by counting the
+chromosomes of its cells. This has been accomplished in several cases.
+
+In some instances[1] the conditions may be much more complex than the
+ones indicated--too complex in fact to warrant detailed discussion in an
+elementary exposition--but the principle remains the same throughout, the
+very complexity when thoroughly understood, strengthening rather than
+weakening the evidence. In a few forms an interesting reversal of
+conditions has been found in that the eggs instead of the spermatozoa show
+the characteristic dimorphism.
+
+Just what the exact relationship between sex-differentiation and the
+_X_-element is has never been clearly established. It is possible that
+this element is an actual sex-determinant, in the ordinary cases one
+_X_-element determining the male condition and two _X_-elements producing
+the female condition. On the other hand it might be argued that it is not
+the determining factor but the expression of other cell activities which
+do determine sex; that is, a sex accompaniment. Or again, it may be one of
+several essential factors which must cooperate to determine sex.
+
+
+SEX-LINKED CHARACTERS
+
+The discovery of the remarkable behavior of certain characters in heredity
+which can only be plausibly explained by supposing that they are linked
+with a sex-determining factor still further strengthens our belief in the
+existence of such a definite factor. Such characters are commonly termed
+sex-linked characters.
+
+=Sex-Linked Characters in Man.--=Since there are a number of them in man
+we may choose one of these, such as color-blindness, for illustration. The
+common form of color-blindness known as Daltonism in which the subject
+can not distinguish reds from greens, a condition which seems to be due to
+the absence of something which is present in individuals of normal color
+vision, is far commoner in men than in women. Its type of inheritance,
+sometimes termed "crisscross" heredity, has been likened to the knight
+moves in a game of chess. The condition is transmitted from a color-blind
+man through his daughter to half of her sons. Or, to go more into detail,
+a color-blind father and normal mother have only normal children whether
+sons or daughters. The sons continue to have normal children but the
+daughters, although of normal vision themselves, transmit color-blindness
+to one-half of their own sons. If such a woman marries a color-blind man,
+as might easily happen in a marriage between cousins, then as a rule
+one-half her daughters as well as one-half her sons will be color-blind.
+
+
+[Illustration: FIG. 14
+
+Diagram illustrating the inheritance of a sex-limited character such as
+color-blindness in man on the assumption that the factor in question is
+located in the sex-chromosome (from Loeb after Wilson). The normal
+sex-chromosome is indicated by a black =X=, the one lacking the factor for
+color perception, by a light X. It is assumed that a normal female is
+mated with a color-blind male.]
+
+
+In such cases what appears to be a mysterious procedure becomes very
+simple if we assume that the defective character is associated with the
+sex-determining factor, or to make it concrete let us say with the
+_X_-element. The chart shown in Fig. 14, p. 62, indicates what the
+germinal condition would be under the circumstances. The column to the
+right represents the maternal, the one to the left the paternal line.
+Since two _X_ means female and one _X_ male, and inasmuch as we have
+assumed that the physical basis of the defect to which color-blindness is
+due is conveyed by the _X_-element, we may represent the defective single
+_X_ of the male in outline only (see first row). It is obvious that after
+the reduction divisions (second row) the mature sex-cells of the female
+will each contain a single normal _X_, the corresponding sex cells of the
+male will contain either no _X_ or a defective _X_. Since if any member of
+the class of spermatozoa containing no _X_, fertilizes an egg the
+resulting zygote (row three) will have but one _X_ and that a normal one,
+the individual which develops from the zygote will be normal as regards
+color vision and moreover will be male because the condition one _X_
+always means maleness. On the other hand, if any member of the class of
+spermatozoa containing the defective _X_ fertilizes an egg two
+_X_-elements are brought together and this of itself means femaleness. In
+this case one of the _X_-elements is defective but the single normal _X_
+is sufficient in itself to produce normal color vision. But when it comes
+to the maturation of the sex-cells of this female, the pair of
+_X_-elements are separated in the usual way with the result that half of
+the mature ova contain a normal _X_ and half a defective _X_ (row four).
+Since in a normal male, however, the mature reproductive cells will
+contain either a normal _X_ or no _X_ (fourth row), any one of four
+different kinds of matings may result. A sex-cell carrying normal _X_ of
+the male may combine with an ovum containing normal X producing a normal
+female (row five). Or such a cell may combine with an ovum carrying the
+defective _X_, also producing a female but one who although of normal
+color vision herself, like her mother, is a carrier of the defect. On the
+other hand, any one of the spermatozoa without an _X_ may combine with an
+ovum containing the normal _X_, in which case a normal male is produced
+and, moreover, one who, like his mother's brothers, is incapable of
+transmitting the defect. However, the sperm-cell devoid of an _X_ is just
+as likely to fertilize an ovum carrying the defective _X_, in which event
+the resulting individual, a male, must be color-blind because he contains
+the defective _X_ alone. In other words, the chances are that one-half the
+sons of a woman whose father was color-blind will be color-blind, the
+other half perfectly normal; and that all of the daughters will be of
+normal color vision although one-half of them will probably transmit the
+defect to one-half of their sons. From a glance at the diagram it is
+readily seen also that a color-blind female could result from the union of
+a color-blind man (see first row) and the daughter of a color-blind man
+(see third row). For half of the gametes of such a female would bear the
+defect as would also that half of the gametes of the male which carry _X_,
+hence the expectation would be that half of the daughters of such a union
+would be color-blind and half would be carriers of color-blindness; and
+that half of the sons would be color-blind and half normal. All the sons
+of a color-blind woman would be color-blind because she has only defective
+_X_-elements to pass on.
+
+The inheritance of various other conditions in man follows more or less
+accurately the same course as color-blindness. Among these may be
+mentioned: _hemophilia_, a serious condition in which the blood will not
+clot properly, thus rendering the affected individual constantly liable to
+severe or fatal hemorrhage; near-sightedness (_myopia_) in some cases; a
+degenerative disease of the spinal cord known as _multiple sclerosis_;
+progressive atrophy of the optic nerve (_neuritis optica_); Gower's
+_muscular atrophy_; some forms of _night-blindness_; in some cases
+_ichthyosis_, a peculiar scaly condition of the skin. In one of my own
+tabulations of a case of inheritance of "webbed" digits or _syndactyly_, a
+condition in which two or more fingers or toes are more or less united, a
+sex-linked inheritance is clearly indicated (Fig. 15), although from the
+pedigrees recorded by other investigators this condition usually appears
+in some of both the sons and daughters of an affected individual.
+
+
+[Illustration: FIG. 15
+
+Chart showing the inheritance of a case of syndactyly after the manner of
+a sex-linked character. The affected individuals are represented in black;
+squares indicate males, circles females. The condition is seen to be
+inherited by males through unaffected females.]
+
+
+=The Occurrence of Sex-Linkage in Lower Forms Renders Experiments
+Possible.--=The course followed by such characters in man can be inferred
+only from the pedigrees we can obtain from family histories. Fortunately,
+however, such sex-linkage also occurs in lower animals and we are able
+therefore to verify and extend our observations by direct experiments in
+breeding. Several sex-linked characters have been found to exist in a
+small fruit-fly known as _Drosophila_. Extensive breeding experiments with
+this fly by Professor T. H. Morgan and his pupils have borne out
+remarkably the interpretation that the characters in question are really
+linked with a sex-determining factor.
+
+
+
+
+CHAPTER III
+
+MENDELISM
+
+
+=New Discoveries in the Field of Heredity.--=Writing in 1899, one of
+America's well-known zoologists asserts that, "It is easier to weigh an
+invisible planet than to measure the force of heredity in a single grain
+of corn." And yet only two or three years later we find another prominent
+naturalist saying regarding heredity that, "The experiments which led to
+this advance in knowledge are worthy to rank with those that laid the
+foundation of the atomic laws of chemistry." Again, "The breeding pen is
+to us what the test-tube is to the chemist--an instrument whereby we
+examine the nature of our organisms and determine empirically their
+genetic properties." Here is a decided contrast of statement and yet both
+were justifiable at the time of utterance. For even at the writing of the
+first statement the investigations were in progress which, together with
+the rediscovery of certain older work, were to transfer our knowledge of
+heredity from the realm of speculation to that of experiment and disclose
+certain definite principles of genetic transmission.
+
+Through a knowledge of these principles in fact, the shifting of certain
+characters is reducible to a series of definitely predictable proportions
+and the skilled breeder may proceed to the building up of new and
+permanent combinations of desirable characters according to mathematical
+ratios and, what is of equal importance, he can secure the elimination of
+undesirable qualities. While there are many limitations in the application
+of these principles and while new facts and modifications are constantly
+being discovered concerning them, nevertheless they represent the first
+approximations to definite laws of hereditary transmission that we have
+ever been able to make, and the practical fact confronts us that whatever
+our theoretical interpretations may be, the principles are so definite
+that through their application important improvements of crops and
+domesticated animals have already actually been secured and one may
+confidently expect still others to follow.
+
+=Mendel.--=The principles involved are called the Mendelian principles
+after their discoverer, Gregor Johann Mendel, abbot of a monastery at
+Brünn, Austria. After eight years of patient experimenting in his cloister
+garden with plants, chiefly edible peas, he published his results and
+conclusions in 1866, in the _Proceedings of the Natural History Society of
+Brünn_. While known to a few botanists of that day, the full importance of
+the contribution was not recognized, and in the excitement of the
+post-Darwinian controversy, the facts were lost sight of and ultimately
+forgotten.
+
+=Rediscovery of Mendelian Principles.--=In 1900 three men, Correns, De
+Vries and Tschermak, working independently--in different countries, in
+fact--rediscovered the principles and called attention anew to the
+long-forgotten work of Mendel which they had come upon in looking over the
+older literature on plant breeding. These investigators added other
+examples from their own experiments. Since their rediscovery the
+principles have been confirmed in essential features and extended by
+numerous experimentalists with regard to a wide range of hereditary
+characters in both animals and plants.
+
+=Independence of Inheritable Characters.--=It has been found that many
+truly heritable characteristics or traits of an individual, whether plant
+or animal, are comparatively independent of one another and may be
+inherited independently. Where there are contrasted characters in father
+and mother, such as white plumage and black plumage in fowls, smooth coat
+and wrinkled coat in seed, horns and hornlessness in cattle, long fur and
+short fur in rabbits, beard and beardlessness in wheat, albino condition
+and normal condition, etc., there is obviously a bringing together of the
+determiners of the two traits in the resulting offspring. In the third
+generation, however, in the progeny of these offspring, the two distinct
+characters may be set apart again, thus showing that in the second
+generation while perhaps one only was visible, the factors which determine
+both were nevertheless present, and moreover, they were present in a
+separable condition.
+
+=Illustration of Mendelism in the Andalusian Fowl.--=Let us take as a
+simple example the case of the Andalusian fowl. Although it is not a case
+established by Mendel it illustrates certain of the essential conditions
+underlying Mendelism in a more obvious way than the cases worked out by
+Mendel himself. The so-called blue Andalusian fowl results from a cross of
+a color variety of the fowl which is black with one which is white with
+black-splashed feathers. The result is the same irrespective of which
+parent is black. When bred with their like, whether from the same parents
+or different parents, these blue fowls produce three kinds of progeny,
+approximately one-fourth of which are black like the one grandparent,
+one-fourth white like the other grandparent, and the remaining half, blue
+like the parents (Fig. 16). Moreover, the black fowls obtained in this way
+will, when interbred, produce only black offspring and the same is true of
+the white fowls. To all appearances as far as color is concerned they are
+of as pure type as the original grandparents. With the blue fowls,
+however, the case is different, for when bred together they will produce
+the same three kinds of progeny that their parents produced and in the
+same proportions. Again the white and the black are true to type but the
+blue will always yield the three classes of offspring and this through
+generation after generation.
+
+
+[Illustration: FIG. 16
+
+Diagram showing the scheme of inheritance in the blue Andalusian fowl.]
+
+
+These facts may be illustrated graphically as follows where the word
+"black" indicates the original black parent, "white" the original white
+(black splashed) parent and "blue" the hybrid offspring.
+
+  Parental
+  Generation (P)          Black × White              Black × White
+                                |                          |
+  First Filial                  |                          |
+  Generation (F_{1})          Blue          ×           Blue
+                                             |
+                        +------------------------------------------+
+                        |                    |                     |
+  Second Filial       Black                 Blue                 White
+  Generation (F_{2})  (25%)                 (50%)                (25%)
+                        |                    |                     |
+                        |        +-------------------------+       |
+                        |        |           |             |       |
+  Third Filial        Black   Black         Blue          White  White
+  Generation (F_{3})    |     (25%)         (50%)         (25%)    |
+                        |        |           |             |       |
+                        |        |     +-------------+     |       |
+                        |        |     |     |       |     |       |
+  Fourth Filial       Black   Black  Black  Blue   White  White  White
+  Generation (F_{4})                 (25%)  (50%)  (25%)
+
+=The Cause of the Mendelian Ratio.--=Concerning the cause of this peculiar
+ratio of inheritance in crossed forms Mendel suggested a simple
+explanation. Animals or plants that can be cross-bred, obviously must be
+forms that produce a new individual from the union of two germ-cells, one
+of which is provided by each parent. Mendel's idea was that there must be
+some process of segregation going on in the developing germ-cells of each
+hybrid whereby the factors for the two qualities are set apart in
+different cells with the result that half of the germ-cells of a given
+individual will contain the determiner of one character and half, the
+determiner of the other. That is, a given germ-cell carries a factor for
+one or the other of the two alternate characters but not the factors for
+both. In a plant, for example, in the male line, half of the pollen grains
+would bear germ-cells carrying the determiner of one character and half,
+that of the other. Similarly, in the female line, half of the ovules would
+contain the determiner of the one character and half, that of the other.
+Likewise in animals as regards such pairs of characters there would be two
+classes of germ-cells in the male and two in the female. In the case of
+the blue Andalusian fowls under discussion this would mean that half of
+the mature germ-cells of the male carry the black-producing factor, and
+half carry the white-producing factor, and the same is true of the
+germ-cells of the female. Thus when two such crossed forms are mated,
+there are, by the laws of chance, four possible combinations, namely: (1)
+white-determining sperm-cells and white-determining ovum; (2)
+white-determining sperm-cells and black-determining ovum; (3)
+black-determining sperm-cells and white-determining ovum; and (4)
+black-determining sperm-cells and black-determining ovum. Manifestly, the
+first combination can only give white offspring; the second, white and
+black, gives blue (by such a cross the original blues were established);
+likewise, the third, black and white, gives blue; and the fourth
+combination can only give black offspring. This matter may be graphically
+represented by the following formulæ in which B indicates the determiner
+of Black in the germ-cell and W the determiner of White: [male] signifies
+male; [female] female.
+
+
+IN THE ORIGINAL PARENTS
+
+  W × B = WB = Blue
+
+IN THE HYBRIDS
+
+  [male] [female]
+  germ-  germ-
+  cells  cells     [male] [female]
+    W----W          W   ×   W = WW = White
+      \/            W   ×   B = WB = Blue
+      /\      or    B   ×   W = BW = Blue
+    B----B          B   ×   B = BB = Black
+
+Thus of the four possible combinations one only can produce white fowls,
+two (WB or BW) can produce blue fowls, and one black fowls. That is, the
+ratio is 1:2:1 or the 25, 50 and 25 per cent., respectively, of our
+diagram. The black fowls or the white fowls will breed true in subsequent
+generations when mated with those of their own color because the
+determiner of the alternative character has been permanently eliminated
+from their germ-plasm; but the blue fowls will always yield three types of
+offspring because they still possess the two classes of germ-cells.
+
+=Verification of the Hypothesis.--=The hypothesis that germ-cells of
+crossed forms are of two classes with respect to a given pair of Mendelian
+characters is further substantiated by the following facts. If in the case
+of the fowls under discussion one of the blue fowls is mated with an
+individual of the white variety, half of the progeny will be blue and
+half white. For the hybrid has two kinds of germ-cells, black producing,
+which we have designated by the letter B, and white producing (or W) in
+equal number while the white parent has only one kind, white producing. It
+is obvious that if half the germ-cells of the hybrid form are of the type
+B then half the progeny will be of the BW type, which is blue, and the
+other half will be of the WW type, which is white. In the same way if we
+mate a hybrid and a black fowl, half of the progeny will be black and half
+will be blue, that is, there could only be WB and BB types.
+
+The fact must not be lost sight of that since the pairings are wholly
+determined by the laws of chance the proportions are likely to be only
+approximate. It is obvious that the greater the number of individuals, the
+nearer the results will approach the expected ratio.
+
+
+DOMINANT AND RECESSIVE
+
+=One Character May Mask the Other.--=In a large number of cases, however,
+the actual condition of affairs is not so evident as in the Andalusian
+fowl, for instead of being intermediate or different in appearance, the
+generation produced by crossing resembles one parent to the exclusion of
+the other. Such an overshadowing is spoken of as _dominance_, and the two
+characters are termed _dominant_ and _recessive_. Thus when brown
+ring-doves and white ring-doves are mated the progeny are all brown, or if
+wild gray mice are mated to white mice the progeny are all gray. So black
+is dominant to white in rose-comb bantams; brown eyes to blue eyes in man;
+beardlessness to beard in wheat, and likewise rough chaff to smooth, and
+thick stem to thin; tallness to dwarfness in various plants; normal
+condition to the peculiar waltzing condition in the Japanese waltzing
+mouse. Numerous other cases might be cited but these are sufficient to
+illustrate the condition.
+
+=Segregation in the Next Generation.--=But now the question arises, what
+do such crosses as show dominance transmit to the next generation?
+Experiments show regarding any given pair of these alternate characters
+that they are set apart again in the succeeding generation, returning in a
+definite percentage to the respective grandparental types.
+
+
+[Illustration: FIG. 17
+
+Diagram showing the scheme of inheritance in guinea-pigs when black and
+albino forms are crossed.]
+
+
+=Dominance Illustrated in Guinea-Pigs.--=In guinea-pigs for example (Fig.
+17), when an individual (either male or female) of a black variety, is
+crossed with one of a white variety, the F_{1} generation are all black
+like the black parent. When these are interbred or bred with other blacks
+which have had one black and one white parent, only two visible types of
+progeny appear, viz., black and white, and these approximately in the
+ratio of three to one.
+
+Analysis by further breeding shows, however, that there are in reality
+three types, but since dominance is complete the pure extracted dominant
+and the mixed dominant-and-recessive type are indistinguishable to our
+eye. That is, while the blacks are three times as numerous as the whites,
+two out of every three of these blacks are really hybrid and correspond to
+the blue fowls of our former example.
+
+The condition is readily comprehended when expressed diagrammatically
+thus:
+
+  Generation P           Black × White       Black × White
+                               |                 |
+  Generation F_{1}        Black (White)  ×   Black (White)
+                                         |
+                      +-------------------------------------+
+                      |                  |                  |
+  Generation F_{2}  1 Black       2 Black (White)       1 White
+
+In other words, the germ-cells of the one original parent (Gen. P) would
+contain only determiners for black and that of the other parent would
+contain only determiners for white. The condition of the individuals
+produced by the cross would be represented by the formula B(W). But these
+determiners segregate in the germ-cells of the crossed form, whether it be
+male or female, into B and W. Hence half the spermatozoa of the male
+hybrid (generation F_{1}) would carry the B determiners and half the W
+determiners. The same is true of the mature ova of the female hybrid.
+Consequently, in mating there are always four equally possible
+combinations, viz., BB, B(W), (W)B, and WW. Since B is always dominant
+three out of the four matings would yield black individuals, or in other
+words the ratio would be 3:1.
+
+The pure blacks when mated together will breed true in subsequent
+generations, likewise the whites, but the blacks carrying white as a
+recessive will yield when interbred the same ratio of whites and black as
+did their hybrid parents (Fig. 17, p. 75).
+
+=Terminology.--=As work in the study of Mendelian inheritance has
+progressed and expanded the need of a more precise terminology has become
+evident and such is gradually being established. Thus Professor Bateson
+has coined the term "allelomorph" (Gk. _one another_, and _form_) to
+express more exactly what we have thus far been calling a pair of
+alternate or opposite characters. In the blue Andalusian fowls discussed,
+the white condition in the one parent is the allelomorph of the black
+condition in the other. The term generally means one of the pair of
+Mendelian characters themselves as expressed in the individual plants or
+animals but when the germinal basis of such phenomena is under discussion,
+it is sometimes used to refer to the determiners of such characters. And
+by determiner is meant simply the condition which is necessary in the germ
+to bring about the occurrence of a definite character. For example, when
+we are studying a cross between a red flower and a white flower with
+reference to the color factors, the difference between the two plants may
+lie in the fact that one produces a red coloring matter and the other
+does not. That is, the determiner for red is absent from the white
+variety. What the exact relation of color production is to the parts of
+the germ-cell we do not know. It could be the function of a single
+definite body or the resultant of several cooperating bodies. The latter
+is far more likely to be the case. We may suppose that a group of
+cooperating substances function to produce red in the red flower but that
+in the white flowers one of these bodies is absent or fails to perform its
+red-producing function.
+
+It is customary where practicable to refer to the determiner of a
+character by the initial letter of the name of the character. The letter
+when written as a capital indicates the determiner but when written as a
+small letter the absence of the determiner. Thus R may be taken to
+represent the determiner for red coloring matter and r its absence. It is
+convenient also to have a brief symbol to denote a given generation and
+for this purpose Bateson has introduced the symbol F_{1} for the hybrid
+progeny of the first cross, the initial letter of the word "filial." F_{2}
+would indicate the next generation, F_{3} the third and so on. Likewise P
+denotes the original parent generation.
+
+=The Theory of Presence and Absence.--=Many, if not all, allelomorphs
+consist of the presence and absence respectively of a given determiner. In
+such cases the character represented by the presence of the determiner is
+dominant over the character represented by the absence of a determiner.
+Thus in the crosses from the wild gray mice and albino mice the progeny
+are all gray mice since one parent had the determiner or group of
+determiners for grayness and the hybrid offspring must also possess it.
+Likewise the presence of black in black guinea-pigs is dominant to its
+absence in albino guinea-pigs and the resulting progeny are all black.
+
+However, it has already been mentioned that beardlessness in wheat is
+dominant to beard and that the absence of horns in cattle is dominant to
+their presence, that is, the progeny of hornless by horned cattle are
+without horns except for occasional traces of imperfect horns. Facts like
+these would seem at first sight to contradict the assertion just made that
+presence is dominant to absence, but it is fairly well established that in
+such cases one is not dealing with true absences but with suppressions.
+The polled breeds of cattle, for example, are hornless not because of the
+absence of determiners for horns but because of the presence of an
+additional inhibiting factor which prevents these determiners from
+functioning. The horned breeds are without this inhibitor. When horned and
+hornless individuals are crossed the presence of the inhibitor from one
+line of ancestry is sufficient to suppress the development of horns in the
+progeny. A similar explanation would, of course, apply to beardlessness in
+wheat.
+
+In writing double-lettered formulæ to denote the determiners of characters
+in hybrids the condition is represented merely by the capital and small
+letter. Thus Rr indicates that red is dominant to its absence.
+
+=Additional Terminology.--=In pure breeds where the determiners are alike
+as BB in black or bb in albino guinea-pigs, the individual is said to be a
+_homozygote_ (like things united) with reference to that character, while
+in those in which the determiners are unlike, as Bb, the individual is
+termed a _heterozygote_ (unlike things united) with reference to the
+character. Or to use the adjective forms, a pure black guinea-pig is
+homozygous for black pigment, an albino guinea-pig is homozygous for
+absence of pigment, while a cross between the two is heterozygous for
+pigment. Also, where the determiner of a given character is present in
+double quantity, that is, from both lines of ancestry, the individual is
+said to be _duplex_, where represented in only the single form as in
+heterozygous individuals, _simplex_, and where the determiner is absent
+entirely, _nulliplex_, with reference to the character in question. Thus
+black guinea-pigs of formula BB are duplex with regard to the determiner
+for black color, individuals of formula Bb are simplex with reference to
+this determiner, and those of formula bb are nulliplex.
+
+A heterozygote in which dominance prevails can be identified with
+certainty by breeding to a known recessive and noting the kind of
+offspring produced. If the individual was really a heterozygote,
+approximately fifty per cent. of the offspring should be of the recessive
+type.
+
+=Dominance Not Always Complete.--=As a matter of fact close inspection
+shows that in numerous instances dominance is not absolute since traces of
+the recessive character may be detectable. For example, in the cross
+between smooth and bearded wheat while smoothness is regarded as the
+dominant character and beardlessness as the recessive, nevertheless in the
+hybrid offspring a slight tendency toward bearding is not infrequently
+seen. Or again when horned breeds of cattle are crossed with hornless
+ones, a small proportion of such progeny will show traces of imperfect
+horns.
+
+In some cases instead of either character dominating the other a form
+intermediate between the two parents may result, as we have seen already
+in the case of the Andalusian fowl. Thus, certain white-flowered plants
+and certain red-flowered plants when crossed produce pink hybrids, and
+longheaded and shortheaded wheats when crossed give offspring with heads
+of intermediate length. Or again, crosses between white and red cattle may
+yield red roans, and between black and white cattle, blue roans.
+
+Thus, while for such pairs of alternative characters as have been studied,
+dominance to some considerable degrees at least, seems to be the rule,
+still we have gradations down to the intermediate condition, and in some
+instances the hybrid with respect to a given character may be unlike
+either parent. The things of chief importance in the Mendelian discovery
+are the independent, unitary nature of the characters and their
+segregation in the offspring of cross-bred forms.
+
+=Modifications of Dominance.--=It should be noted also that there is such
+a condition as _delayed dominance_. Davenport found, for example, that
+chicks produced by crossing pure white with pure black Leghorn fowls are
+speckled black and white, but later in the adult form white becomes
+dominant. Likewise conditions of delayed dominance are known in man in
+eye-color and notably in color of hair. Some few cases have been recorded
+where a character is dominant at one time, recessive at another.
+According to Davenport extra toe in fowls may behave in this way.
+
+=Mendel's Own Work.--=Mendel[2] himself worked out his principles on seven
+pairs of characters which he found in common culinary peas. Placing the
+dominant characters first, these may be enumerated as follows: (1) Tall by
+dwarf; (2) green pod (unripe) by yellow; (3) pod inflated by pod
+constricted between the individual peas; (4) flowers arranged along the
+axis of the plant by flowers bunched together at the top; (5) seed skin
+colored by seed skin white; (6) cotyledons yellow by cotyledons green; (7)
+seed rounded by seed wrinkled.
+
+He found that each pair of characters followed the same law as any other
+pair when more than one pair of the characters occurred in the same
+plants, but that each pair behaved independently of the other. The meaning
+of this is that we may get various combinations of characters not
+associated in the original pure stocks, the number of such combinations
+depending on the number of pairs of allelomorphs there are.
+
+
+DIHYBRIDS
+
+=Getting New Combinations of Characters.--=Since this principle is well
+illustrated in peas, let us take two pairs of their characters, viz.,
+greenness and yellowness (of the cotyledons) and roundness and angularity
+to see exactly what happens when two pairs of allelomorphs are involved.
+When a specific kind of yellow pea is crossed with a particular kind of
+green pea the offspring are always yellow (Fig. 18, opposite p. 84). When
+these hybrids (generation F_{1}) are self-fertilized there is the usual
+Mendelian segregation; one-fourth the resulting offspring will be green,
+one-fourth pure yellow, and one-half, although yellow in appearance, will
+be of the mixed type. The exact numbers found by Mendel were 6,022 yellow
+seeds to 2,001 green seeds. Now of the original peas (generation P) the
+yellow ones are round and the green ones angular (really wrinkled).
+Choosing this roundness and angularity respectively as a pair of
+characters they are found to follow the same law that the colors follow
+(Mendel obtained in the F_{2} generation 5,474 round and 1,850 wrinkled
+seed), but independently of the latter. For while in the progeny of the
+hybrids (Gen. F_{1}), twenty-five per cent. will be round and of pure type
+as regards roundness, twenty-five per cent. angular, and fifty per cent.
+round but containing hidden factors of angularity (i. e., roundness is
+dominant), the roundness and the yellowness, or the angularity and the
+greenness will not always go together as they did in the original
+grandparental strains, but there will be in addition some new types of
+round green peas and some of angular yellow ones. That is, the factors of
+color and of shape have been inherited independently of one another, so
+that instead of the two original kinds of peas, four have been produced,
+viz., (1) round-yellow (one of the original types); (2) round-green (new
+type); (3) angular-yellow (new type); and (4) angular-green (one of the
+original types). Furthermore, these will be found to stand in the ratio of
+9:3:3:1 respectively.
+
+=Segregations of the Determiners.--=How these combinations come about in
+this definite proportion is easily understood if the matter is expressed
+in terms of determiners and the possible matings tabulated (Fig. 18). If
+we represent the yellow determiner by Y and the green determiner by y, and
+likewise the determiners of roundness and angularity by R and r
+respectively, then the formulæ for the determiners of these two pairs of
+characters in the body cells (that is, in the unreduced condition) of the
+pure forms and of the F_{1} generation hybrids respectively are as
+follows:
+
+  In pure round yellow peas       RR YY
+  In pure angular green peas      rr yy
+  In the hybrid                   Rr Yy
+
+But now in the segregation of these determiners in the germ-cells of the
+hybrids (generation F_{1}) the pair of determiners Rr and the pair Yy
+operate entirely independently of one another. Their only compulsion is
+that each pair be separated into the single determiners, R and r in the
+one case and Y and y in the other. So in the separating division which
+brings about this divorcement R separates from r irrespective of whether
+it is accompanying Y or y into the resulting daughter cell. Thus in some
+cases R and Y would pass into one germ-cell, in others R and y, in others
+r and Y, and in still others r and y, depending entirely upon the
+chance relations of the respective pairs to the plane of division. That
+is, the segregation is equally likely to be RY/ry giving gametes RY and
+ry, or Ry/rY giving gametes Ry and rY.
+
+
+[Illustration:
+
+       \[Female]
+  [Male]\   RY       Ry       rY       ry
+         +-------+--------+--------+--------+
+    RY   | RRYY  |  RRYy  |  RRYY  |  RrYy  |
+         +-------+--------+--------+--------+
+    Ry   | RRYy  |  RRyy  |  RrYy  |  Rryy  |
+         +-------+--------+--------+--------+
+    rY   | RrYY  |  RrYy  |  rrYY  |  rrYy  |
+         +-------+--------+--------+--------+
+    ry   |  RrYy |  Rryy  |  rrYy  |  rryy  |
+         +-------+--------+--------+--------+
+
+      (1) 1 RRYY    (4) 2 RrYY    (7) 1 rrYY
+      (2) 2 RRYy    (5) 4 RrYy    (8) 2 rrYy
+      (3) 1 RRyy    (6) 2 Rryy    (9) 1 rrYy
+                      9:3:3:1
+
+FIG. 18
+
+Diagram showing the possible combinations arising in the second filial
+generation (F_{2}) following a cross between yellow, round (YYRR) and
+green, angular or wrinkled (yyrr) peas. Y, presence of factor for yellow;
+y, absence of such a factor; R, presence of factor for smoothness or
+roundness; r, absence of such a factor; [male] male; [female] female.]
+
+
+=Four Kinds of Gametes in Each Sex Means Sixteen Possible
+Combinations.--=There are, therefore, with reference to the two pairs of
+characters under consideration, four kinds of gametes (or mature
+germ-cells) produced in equal numbers in each hybrid, viz., RY, Ry, rY,
+and ry. That is, in the first type roundness and yellowness are
+associated, in the second roundness and greenness, in the third angularity
+(lack of roundness) and yellowness, and in the fourth angularity and
+greenness.
+
+But since both males and females have these four kinds of gametes, when
+they are mated there will be sixteen possible combinations. These may be
+tabulated as in Fig. 18, opposite p. 84.
+
+=The 9:3:3:1 Ratio.--=While there are sixteen possible and equally
+probable combinations, these will give only nine distinct kinds because
+some of the matings are alike. The numbers of the various kinds of matings
+are as follows:
+
+  (1) 1 RRYY    (4) 2 RrYY    (7) 1 rrYY
+  (2) 2 RRYy    (5) 4 RrYy    (8) 2 rrYy
+  (3) 1 RRyy    (6) 2 Rryy    (9) 1 rrYy
+
+Since roundness (R) and yellowness (Y) are dominant to angularity (r) and
+greenness (y) in all combinations containing R or Y, the alternative
+determiners r or y would be obscured, with the result that individuals
+having certain of the combinations would look alike to our eye. For
+example, the individuals represented by numbers 1, 2, 4 and 5, since they
+contain dominant R and Y, would all appear round and yellow, although in
+reality No. 1 would be the only one of pure type (both elements
+homozygous) and hence the only one that would breed true in subsequent
+generations. The two individuals represented in No. 2 would breed true as
+regards shape (RR) but not color (Yy). Just the reverse is true of No. 4
+since shape is heterozygous (Rr) and color homozygous (YY). The four
+individuals represented in No. 5 are heterozygous with regard to both
+elements. Thus nine individuals (1 plus 2 plus 2 plus 4 = 9) represented
+in Nos. 1, 2, 4 and 5 would be round and yellow, three individuals (Nos. 3
+and 6) would be round and green, three (Nos. 7 and 8) would be angular and
+yellow, and only one (No. 9) would be angular and green. That is to say,
+the four classes discernible to the eye in generation F_{2} would be
+present in the ratio of 9:3:3:1.
+
+=Phenotype and Genotype.--=Forms such as those represented in Nos. 1, 2, 4
+and 5 which to the eye appear to be alike, regardless of their germinal
+constitution, are said to be of the same _phenotype_. Those of the same
+hereditary constitution, as the two individuals represented in No. 8, or
+the four individuals in No. 5, are said to be of the same _genotype_, that
+is, they are of identical gametic constitution.
+
+As we have seen, it is from the genotypical not the phenotypical
+constitution that an offspring is derived and what a given form will bring
+forth depends then on its genotype.
+
+=Crosses With More Than Two Pairs of Characters.--=In crosses in which
+more than two pairs of contrasted characters are involved the underlying
+principles are in no way different, only with each pair of additional
+characters there is, of course, a greater number of possible combinations.
+Thus with three pairs of characters there will be eight different classes
+of gametes in each sex and consequently sixty-four possible combinations
+in mating, giving eight different phenotypes in the proportion of
+27:9:9:9:3:3:3:1. The largest class manifests the three dominant
+characters; the smallest class, the three recessives; the three classes in
+the proportion of 9 each exhibit two dominant and one recessive
+characters; and those in the proportion of 3 each display two recessive
+and one dominant characters.
+
+
+THE QUESTION OF BLENDED INHERITANCE
+
+We come now to certain types of inheritance in which there seems to be a
+true fusion or blend of the contributions from the two parents, the
+intermediate condition apparently persisting in subsequent generations
+without segregation. Numerous cases of blended inheritance have been cited
+in earlier literature of heredity, but as our knowledge of genetics has
+progressed many experimental breeders have come to believe that the
+blends in such cases are apparent rather than real and that the phenomena
+can be best explained on a non-blending unit-character basis, just as we
+would explain ordinary Mendelian phenomena.
+
+=Nilsson-Ehle's Discoveries.--=To get their point of view we may review
+certain experiments on wheat made by Nilsson-Ehle, together with their
+Mendelian interpretation. Nilsson-Ehle found that a certain brown-chaffed
+wheat when crossed with a white-chaffed strain yielded a brown-chaffed
+hybrid, apparently in accordance with the simple principle of Mendelian
+dominance. But these heterozygous brown-chaffed individuals did not in
+turn give the expected ratio of 3:1 in the F_{2} generation but a ratio of
+15 brown to 1 white, and furthermore the browns were not all of the same
+degree of brownness. To be exact, from fifteen different crosses of the
+strains he obtained 1,410 brown-chaffed and 94 white-chaffed plants.
+
+This apparent anomaly in segregation was easily explained, however, when
+it was finally figured out that there were really two independent
+determiners for brown color, either of which alone could produce a brown
+individual, but when combined produced individuals of correspondingly
+deeper shades of brown. In such a case then Nilsson-Ehle discovered that
+he was dealing merely with a Mendelian dihybrid where two different
+determiners B and B´ and their respective absences b and b´ are involved.
+The original brown wheat had both B and B´ and the original white b and
+b´. The formula for the F_{1} heterozygote was therefore BbB´b´. The four
+possible types of gametes for male and female are BB´, Bb´, bB´, bb´, and
+the tabulation would be as follows:
+
+       +-----------------------------------
+       |  BB´   |  Bb´   |  bB´   | bb´
+  -----+--------+--------+--------+--------
+   BB´ | BBB´B´ | BBB´b´ | BbB´B´ | BbB´b´
+  -----+--------+--------+--------+--------
+   Bb´ | BBB´b´ | Bb´Bb´ | BbB´b´ | Bbb´b´
+  -----+--------+--------+--------+--------
+   bB´ | BbB´B´ | BbB´b´ | bbB´B´ | bbB´b´
+  -----+--------+--------+--------+--------
+   bb´ | BbB´b´ | Bbb´b´ | bbB´b´ | bbb´b´
+  -----------------------------------------
+
+It will be observed that there are more brown determiners in some
+combinations than others. For instance one of the sixteen contains four
+such determiners, viz., B, B´, B, B´, four contain three determiners, six
+contain two, four contain only one, and one contains none. Thus all but
+one of the sixteen contain at least one determiner and will therefore be
+brown in color but the depth of color will depend on the number of brown
+determiners in a given individual. This is more graphically represented in
+Fig. 19, p. 90. The largest number of similar individuals, six in all,
+contain two determiners each and represent an intermediate "blend" between
+the original brown-chaffed and white-chaffed strains. The deeper and the
+lighter browns due to more or fewer determinants in an individual would if
+one did not know the units in this case look like the fluctuations around
+this average which we might expect in a blend.
+
+
+[Illustration: FIG. 19
+
+Diagram illustrating the proportionate distribution of determiners where
+either of two different determiners produces the same character, the
+degree of expression of the character depending on the number of the
+determiners present. The numerals indicate the number of brown determiners
+present in an individual.]
+
+
+Nilsson-Ehle found another significant case in wheat where one particular
+red-grained strain of Swedish wheat when crossed with white-grained
+strains produced red-grained offspring, but when these were interbred the
+F_{2} generation gave approximately sixty-three red to one white-grained
+individual. Here it was found that in the original red wheat there are
+three separate determiners which act independently of one another in
+heredity, any one of which would make red color; and that they together
+with their absences simply follow the Mendelian laws for a trihybrid.
+
+=Such Cases Easily Mistaken for True Blends.--=If we should tabulate the
+possible combinations as we did the dihybrid we should see that we would
+get individuals having varying numbers of red determiners. Only one of the
+sixty-four possible combinations would be without a factor for red. Of the
+sixty-four, one would have six determiners for red, six would have five,
+fifteen would have four, twenty would have three, fifteen would have two,
+six would have one, and one would have none. Since here every additional
+red factor means deeper redness in the individual there would be varying
+degrees of redness in the F_{2} generation with those having three
+determiners, the largest group, standing apparently intermediate. Not
+knowing the factors involved we might easily mistake such a case for a
+true blend with fluctuations about an average intermediate form.
+Nilsson-Ehle finally proved his interpretation by rearing an F_{3}
+generation from isolated and self-fertilized plants of this F_{2}
+generation.
+
+This same principle of cumulative determiners has also been established in
+America by East with field corn.
+
+As the number of duplicate determiners increases it can be readily seen
+that the number of apparent blends of different degrees of intermediacy
+between the two extremes would rapidly increase.
+
+=Skin-Color in Man.--=In man, the skin-color of the hybrids between
+negroes and whites is often cited as a case of blended inheritance in
+contradistinction to Mendelian inheritance. The skin-color of the mulatto
+of the F_{1} generation is intermediate between that of the white and
+black parent. This same degree of intermediacy is commonly supposed to
+persist in subsequent generations, but as a matter of fact, careful
+investigation has shown that while mulattoes rarely produce pure white or
+pure black children, there is considerably greater range in the shades of
+color in the F_{2} generation and subsequent generations than in the F_{1}
+generation. This is exactly what one would expect of a Mendelian character
+in which several cooperating factors were involved. Indeed, Davenport who
+has made extensive studies[3] on the inheritance of skin-color in man has
+come to the conclusion that the case is really one of Mendelian
+inheritance in which several factors for skin-color are concerned. Even
+the skin of a white man is pigmented in some degree under normal
+conditions. Davenport has shown in the skin of both whites and blacks that
+there is a mixture of black, yellow and red pigments. He concludes that
+"there are two double factors (AABB) for black pigmentation in the
+full-blooded negro of the west coast of Africa and these are separably
+inheritable." Since these factors are lacking in white persons the
+intermediate color of an F_{1} mulatto would therefore be heterozygous for
+pigmentation, and subsequent generations, following the laws for
+segregation where a number of factors are concerned, would show different
+degrees of color because of the varying combinations of factors.
+
+=Some Investigators Would Question the Existence of Real Blends.--=Still
+other reputed blends such as ear length in rabbits and the like have been
+shown to be analyzable into Mendelian behavior if one will but postulate
+numerous or multiple factors. Just how far we are justified in so
+accounting for blends has not yet been established. Some of our most
+careful experimentalists in heredity still believe that real blends exist,
+particularly where the character is quantitatively expressed--that is, as
+more or less of a given size or amount--while others would maintain that
+all alleged blends will probably be found to be resolvable into factors
+which follow Mendelian rule. It must be left for future investigations to
+demonstrate which school is correct.
+
+
+THE PLACE OF THE MENDELIAN FACTORS IN THE GERM-CELLS
+
+=Parallel Between the Behavior of Mendelian Factors and Chromosomes.--=The
+question arises as to whether there is any evidence from the study of
+germ-cells themselves to bear out the Mendelian conception of separation
+of contrasted characters in the gametes of the F_{1} generation. In the
+discussion of the maturation of germ-cells (Chap. II) it has already been
+seen that the chromosomes of the germ-cells are in all probability
+arranged in homologous pairs, one member being of maternal and the other
+of paternal origin, and that furthermore they are closely associated with
+the phenomena of heredity. And since in maturation there is an actual
+segregation of the chromosomes into two sets, half going to one cell and
+half to its mate, a physical basis adequate to the necessities of the case
+is really at hand. It will be recalled that the individuals of a pair
+separate in such a way at the reduction division that the paternal member
+goes to one cell and the maternal member to the other, although each pair
+seemingly acts independently of the others with the result that any mature
+germ-cell may contain chromosomes from each of the original parents but
+never the two chromosomes which earlier made up a pair. The close parallel
+between the behavior of chromosomes and the behavior of Mendelian factors,
+although the two sets of phenomena were discovered wholly independently of
+each other, is obvious. If we suppose that each chromosome bears the
+determiner of a Mendelian character and that chromosomes bearing
+allelomorphic characters make up the various pairs which are seen in the
+early germ-cells of an individual before reduction occurs, then the
+segregation of the individuals of an allelomorphic pair into different
+gametes must result in consequence of the passing of the corresponding
+chromosomes into separate gametes. Fig. 20, p. 95, from Professor Wilson
+represents equally well the segregations of pairs of chromosomes or pairs
+of Mendelian characters.
+
+
+[Illustration: FIG. 20
+
+Diagram showing union of factors from the two separate parents in
+fertilization and their segregation in the formation of germ-cells (after
+Wilson). With four pairs of factors (_Aa_, _Bb_, _Cc_, _Dd_), sixteen
+types of gametes are possible, as shown in the series of small circles at
+the right. The same diagram equally well represents the pairings and
+segregations of chromosomes.]
+
+
+=A Single Chromosome not Restricted to Carrying a Single Determiner.--=It
+has been objected that there may be more pairs of independently heritable
+allelomorphic characters than there are pairs of chromosomes. It is true
+that there are more pairs of characters than pairs of chromosomes but
+there is no reason for supposing that a given chromosome is restricted to
+carrying a single unit-determiner. On the contrary it probably carries
+several or many. Some workers have pointed out that certain units might be
+interchanged during the pairing of chromosomes before the reduction
+division, others that inasmuch as the chromosomes become diffuse and
+granulated during the intervals between divisions it is not improbable
+that the individual units may become separated from their original system
+during such times and that it is a matter of chance into which of the
+homologous chromosomes, A or a, they enter with the re-establishment of
+the chromosomes. On the other hand, cases are known where two or more
+separate characters are permanently associated in inheritance, that is, if
+they enter a crossed form together they come out together in the
+grandchildren as if they were carried in the same unit-body in the
+germ-cell. The only observable unit-bodies that fulfil the necessities of
+such cases are the chromosomes. This tendency of characters to exist in
+groups which are inherited independently of one another is coming more and
+more into evidence as we penetrate farther into the intricacies of
+inheritance, and it is exactly what we would expect on the supposition
+that each chromosome carries the determiners of a number of characters
+instead of a single one.
+
+
+
+
+CHAPTER IV
+
+MENDELISM IN MAN
+
+
+=The Mendelian Principles Probably Applicable to Many Characters of
+Man.--=We are really just beginning to make the proper observations and
+collect the necessary data with reference to the application of Mendelian
+principles to the traits of man. Yet brief as has been our study we have
+disclosed much significant evidence which makes it seem highly probable
+that many of his characters, good and bad, of mind and body are as
+subservient to these laws as are the traits and features of lower forms.
+Davenport and Plate record over sixty human characters or defects which
+are seemingly inherited in Mendelian fashion. Although about fifty of
+these are pathological or abnormal conditions, this does not mean that
+such conditions are more prone to follow Mendelian inheritance but merely
+that being relatively conspicuous or isolated they are easier to follow
+and tabulate.
+
+=Difficult to get Correct Data.--=While it must be said that in many cases
+no simple form of Mendelian tabulation has been unequivocally established,
+yet the general behavior of the various inheritable traits in question is
+so obviously related to the conventional Mendelian course that there seems
+little reason for doubting that they are at bottom the same. Failure to
+obtain exact proportions may be attributable in part to the probability
+that what we loosely regard as a character should in reality be analyzed
+into more elemental components, and above all to the fact that from the
+very nature of the conditions under which human records must be obtained,
+there is considerable chance of inaccuracy or error in such accounts. How
+many human traits follow Mendelian rules remains largely for future
+investigators to establish.
+
+We are handicapped at the outset in man by the many difficulties of
+getting correct data from the genealogies on which we must depend, or in
+fact of getting any genealogy at all, for in this country at least, most
+families keep imperfect records of births and deaths and many of the
+institutions for the various kinds of defectives have little in their
+records that will help us in following out hereditary conditions. Then in
+matters of disease we meet with the fact that many former diagnoses were
+erroneous. In yet other cases, and this is particularly true among mental
+and moral defectives, we are often not sure of the paternity of a given
+child. Furthermore, one is likely to be misled by the proportions which
+may occur in the very limited number of children of any given couple.
+
+Still other difficulties exist. Among these is the fact, for example, that
+in many cases of defect or susceptibility to disease, a given individual
+in the stock may have the trait in an expressible and transmissible form,
+yet it never comes to expression because that individual has been
+fortunate enough to escape the environmental stimulus which would call it
+forth. Thus one highly susceptible to tuberculosis might escape infection,
+or persons hovering on the verge of insanity might never receive the
+precipitating stimulus which would topple them into actual insanity; yet
+each would be wrongfully recorded in a genealogy looking to such traits as
+perfectly normal. Or again if it be a question of intellectual brilliancy
+as shown by accomplishment in the realm of scholarship, or of worldly
+affairs, the ones who although possessing them have had no chance to
+display unusual talents would be tabulated as average whereas in fact they
+should be recorded as of high rank. That this is particularly likely to
+happen in the case of women is evident.
+
+=A Generalized Presence-Absence Formula for Man.--=In man as in lower
+forms some characters or traits are due presumably to the presence of
+determiners or to their absence. Likewise, dominance and recessiveness are
+as much in evidence, for in tracing back pedigrees of various traits we
+find the same forms of tabulation that obtain for these conditions in
+plants and lower animals hold good. For typical cases in man let us use a
+generalized presence-absence formula and the arbitrary symbol A for the
+presence of the determiner of the character (double in the individual,
+single in the germ) and a for its absence. Thus AA represents a condition
+in which similar determiners have been derived from both parents and the
+individual is _duplex_ as regards the character in question; each mature
+germ-cell will have the determiner. Aa represents a condition in which the
+individual has received the determiner from only one parent and is
+therefore _simplex_ with regard to the character; half of the gametes of
+such an individual will have the determiner and half will lack it. Lastly,
+aa represents total absence of the determiner. Such an individual is
+_nulliplex_. He or she will not have the determiner represented in any of
+the gametes, and can not, of course, transmit a trait represented by the
+determiner.
+
+It is evident that six kinds of gametic matings are possible among
+individuals representing these various formulæ. These matings are as
+follows:
+
+                                        Possible
+                                        couplings
+          Matings                      of gametes       Product
+
+  1. Nulliplex x Nulliplex (aa x aa) == a------a == all nulliplex
+                                           \/
+                                           /\
+                                        a------a
+
+  2. Nulliplex x Simplex (aa x Aa)   == a------A == 50 per cent.
+                                           \/       with character
+                                           /\       nulliplex and
+                                        a------a    50 per cent.
+                                                    with it
+                                                    simplex.
+
+  3. Nulliplex x Duplex (aa x AA)    == a------A == all with characters
+                                           \/       simplex
+                                           /\
+                                        a------A
+
+  4. Simplex x Simplex (Aa x Aa)     == A------A == 25 per cent.
+                                           \/       with characters
+                                           /\       duplex, 50 per
+                                        a------a    cent. with it
+                                                    simplex and 25
+                                                    per cent. with
+                                                    it nulliplex.
+
+  5. Simplex x Duplex (Aa x AA)     == A-------A == 50 per cent.
+                                          \/        with character
+                                          /\        duplex and 50
+                                       a-------A    per cent. with
+                                                    it simplex.
+
+  6. Duplex x Duplex (AA x AA)      == A-------A == all duplex.
+                                          \/
+                                          /\
+                                       A-------A
+
+=Indications of Incomplete Dominance.--=While in cases of strict Mendelian
+dominance it is not possible to distinguish directly the simplex from the
+duplex condition, as a matter of fact the individual of simplex
+constitution sometimes has the character represented in the single
+determiner less perfectly developed than in the corresponding character of
+duplex origin. In studying defects in man due to the absence of a
+determiner, where theoretically presence of the determiner (normality) is
+dominant over its absence in individuals of simplex constitution, one
+finds it recorded with increasing frequency that such individuals are more
+or less "intermediate" or are "tainted" with the defect; thus showing that
+the defect though obscured is not wholly in abeyance. Thus individuals
+carrying epilepsy or feeble-mindedness which are regarded as recessive
+traits, while not showing specific feeble-mindedness or epilepsy, may
+nevertheless apparently show a neuropathic taint in the form of migraine,
+alcoholism or other lapse from normality. The condition is seemingly more
+akin in some cases to that found in the offspring of certain red flowers
+crossbred with white flowers, which though red do not show the same
+intensity of color as the original red parent. Just as here the single
+determiner or single "dose" of redness is insufficient to produce the
+intensity of color that appears when the offspring receive two determiners
+for red, one from each parent, so in man a single determiner for normality
+of a specific character is inadequate in some cases to make the individual
+wholly normal. Or possibly some cases are more of the type of those in
+which the character in question, for instance the red color of some wheats
+and corn, may be produced by any one of two or three determiners, the
+intensity of the characters (red color, e. g.) depending on whether one,
+two or three determiners are present.
+
+=Why After the First Generation Only Half the Children May Show the
+Dominant Character.--=If the trait is a simple dominant one it is clear
+that it will appear in each generation and always spring from an affected
+individual. By referring back to our tabulation of possible matings on
+page 100 where the dominant character is represented by the letter A, this
+can be seen at a glance. If the trait is present in the duplex condition
+in one parent and absent from the other, then formula 3 applies; all
+children will show the trait, but in the simplex form (Aa). If the trait
+is present in the simplex form in one parent and absent in the other,
+formula 2 applies. Fifty per cent. of the children will have the character
+in the simplex form (Aa) which means also an even chance of transmitting
+it to their offspring; fifty per cent. will not inherit it and will be
+incapable, furthermore, of transmitting it, since they have become
+nulliplex (aa). In human genealogies if an individual having an unusual
+trait which is inherited as a dominant marries a normal person and half of
+the offspring show the trait (and this is common), this means that the
+parent manifesting the trait had it represented only in the simplex
+condition, otherwise all of the children would have shown it. Even though
+the original ancestor who first developed the condition or structure may
+have had it in a duplex form, it would after the first mating, if this
+were with an individual lacking the trait, be represented only in the
+simplex form (see formula 5) and could never become duplex again unless
+two individuals both having the character married, and then only in
+twenty-five per cent. of the offspring (see formula 3). If the trait is a
+defect all the children showing it, even though marrying normal
+(nulliplex) individuals, will pass it on again to half their children, but
+those who do not show it may ordinarily marry with impunity since its
+non-expression in their make-up means, as far as we know at present, that
+their germ-plasm has been purged of the defect and that they are therefore
+nulliplex with reference to it.
+
+=Eye-Color in Man.--=Of normal characters in man which follow the
+Mendelian formula perhaps eye-color is the best established. Brown or
+black eye-color is due to a _melanin_ pigment absent from the blue or gray
+eye. That is, a brown eye is practically a blue eye plus an additional
+layer of pigment on the outer surface of the iris. The different shades of
+brown and the black are due to the relative abundance of this pigment.
+Gray color and the shades of blue seem to be a modification of an original
+dark blue, due to structural differences in the fibrous tissues of the
+iris.
+
+In inheritance brown or black is dominant to blue or gray, or in other
+words the _presence_ and _absence_ of a pigment P constitutes a pair of
+allelomorphs. Hence two brown-eyed parents, if P is duplex in both (or
+duplex in one and simplex in the other) can have only brown-eyed children.
+Thus,
+
+  1. PP × PP = PP, or all duplex brown.
+
+  2. PP × Pp = PP and Pp, half duplex brown and half simplex brown.
+
+If each parent has brown eyes but in simplex condition, then one-fourth
+of children will have blue or gray eyes; for example,
+
+  Mating   Gametic              Product
+          couplings
+
+  Pp × Pp = P--P   =  PP, Pp, pP, and pp, or one-fourth
+             \/       duplex brown, one-half simplex
+             /\       brown, and one-fourth blue or
+            p--p      gray.
+
+If both parents have blue or gray eyes they can not have children with
+black or brown eyes, since the recessive condition in each parent means
+total absence of brown pigment in both.
+
+If one pair is duplex brown and the other blue, then all children will
+have brown eyes but of simplex type.
+
+If one parent has simplex brown eyes (type Pp) and one blue (pp) then
+one-half of the children will have brown eyes of simplex type and one-half
+will have blue eyes.
+
+Occasional objections have been raised against the Mendelian
+interpretation of inheritance in eye-color, but the cases cited in
+evidence against the theory usually narrow down to those in which the
+color is so diluted as to render classification uncertain. For example,
+hazel eyes are sometimes called gray; they belong however to the melanic
+pigmented type although the brown pigment may be much diluted and occur
+mainly around the pupil. So-called green eyes are due to yellow pigment on
+a blue background. In the rare cases where in the same individual one eye
+is brown and the other blue, the individual should probably be rated as
+brown-eyed on the supposition that in the one eye the development of brown
+pigment has in some way been suppressed.
+
+=Hair-Color.--=The inheritance of hair-color has also been the subject of
+considerable study and while the conditions are not so simple as in the
+case of eye-color, there is little doubt that it belongs in the Mendelian
+category. In human hair, color has as its foundation apparently two
+pigments, black and red. Absence of one or both or various combinations or
+dilutions of these seemingly account for the prevailing colors in human
+hair. In general dark hair is dominant to light, although because of the
+delay sometimes in the darkening of the hair in children this fact is
+often obscured. Black is dominant to red. People with glossy black hair,
+according to Davenport, are probably simplex for black, the glossiness
+being due usually to recessive red. The expectation would be for some of
+the children of such a pair to have red hair.
+
+In man occasionally a congenital white lock contrasting strikingly with
+the remaining normally pigmented hair occurs. It behaves as a simple
+dominant in heredity.
+
+=Hair-Shape.--=Again, straight and curly hair seem to be distinct
+inheritable characters. Curly is incompletely dominant to straight, the
+simplex condition yielding wavy hair.
+
+Not to enter into details of the matings, statistics gathered by Mr. and
+Mrs. Davenport show that, two flaxen-haired parents have flaxen-haired
+children; two golden-haired parents have only golden-haired children; two
+parents with light brown hair have children with hair of that color or
+lighter, but never darker; two parents each with dark brown or black hair
+may have children with all the varieties of hair-color. Summing together
+a series of recessives Davenport points out that two blue-eyed, flaxen or
+golden and straight-haired parents will have only children like
+themselves.
+
+
+[Illustration: FIG. 21
+
+Diagram showing descent of brachydactyly through five generations; black
+symbols indicate affected individuals; [male], male; [female], female
+(after Farabee).]
+
+
+=Irregularities.--=If a dominant trait or defect depends on more than a
+single factor, as is sometimes the case, or if it is modified by sex or
+other conditions, as is true of certain characters, some of which, such as
+color-blindness, have already been examined, then we shall find some
+apparently non-affected individuals having affected offspring. Certain
+diseases, for example, are generally transmitted by affected members of
+the family to their children in the expected Mendelian ratio for a
+dominant, yet an occasional skip of a generation may appear in which an
+apparently perfectly normal individual transmits to his children what,
+except for the omission in his own case, appears to be an ordinary
+dominant character. This occasional lapse in the appearance of a
+character when theoretically it should appear is doubtless due in some
+instances to the fact that what is really inherited is a _tendency_, and
+although this is present in the apparently normal individual, for some
+reason the condition itself has not appeared. This might especially be
+true in the case of a disease which does not manifest itself until late in
+life. In other cases there are undoubtedly complicating accessory
+conditions which modify the behavior of the trait somewhat.
+
+
+OTHER CASES OF DOMINANCE IN MAN
+
+Among other normal characters in man, as far as available evidence goes,
+dark skin is dominant to light skin; normally pigmented condition to
+albino; and nervous temperament to phlegmatic.
+
+=Digital Malformations.--=An interesting and easily followed defect is a
+condition known as _brachydactylism_, in which the digits are shortened
+because of the absence or rudimentary condition of one segment. The
+fingers, therefore, appear to be only two-jointed like the thumb. Several
+families showing this defect have been charted and it appears to behave as
+a typical dominant. In looking over such a chart (Fig. 21, p. 106) one is
+struck by the fact that only half of the children from most of the matings
+show the defect, but when we recall that the affected parent, after the
+first generation, probably carried the condition in only the simplex form
+and married a normal individual, such a result is just what would be
+expected (see formula 2).
+
+_Polydactylism_ (Figs. 22, 23, pp. 109, 110) is a condition in which there
+are extra digits on hands or feet. The character, with apparently slight
+exceptions in a few records, behaves as a typical dominant. Among other
+digital defects which are inherited as a dominant is a condition known as
+_syndactylism_ (Fig. 24, p. 111), in which two or more digits are fused
+side by side. For an example of syndactyly which seems to be in the class
+of sex-linked characters, see Fig. 15, p. 65.
+
+=Eye Defects.--=_Congenital cataract_ is another not uncommon defect in
+man which is transmitted as a dominant (Fig. 25, p. 112) with occasional
+irregularities. It is a condition of opacity of the lens of the eye which
+produces partial or total blindness. In a paper on _Hereditary Blindness
+and Its Prevention_, Clarence Loeb (1909) mentions 304 families of which
+pedigrees have been published. Of the 1,012 children in these families
+589, or 58 per cent., were affected. It is obvious that this is near the
+expected percentage in the case of a dominant trait where matings of
+affected with normal individuals prevailed. An unfortunate circumstance
+about this malady from the eugenic standpoint is the fact that it is
+frequently of the presenile form which comes on late in life so that it is
+usually impossible to predict whether an individual of marriageable age is
+immune or will later become affected.
+
+
+[Illustration: FIG. 22
+
+Radiograph (Courtesy of Dr. W. B. Helm) showing polydactyly in a child's
+hand. For genealogy of this see Fig. 23, p. 110.]
+
+
+[Illustration: FIG. 23
+
+Chart showing a history of polydactylism through five generations in the
+B---- family. The individual whose hand is pictured in Fig. 22, p. 109, is
+of the fifth generation. Squares represent males, circles females.]
+
+
+Another defect of the eye following the course of a dominant in heredity
+is a pigmentary degeneration of the retina known as _retinitis
+pigmentosa_. Atrophy of the optic nerve is also involved and the final
+result is blindness. Still another example frequently cited is that of
+hereditary night blindness (_hemeralopia_), a disease in which the
+affected person can not see by any but the brightest light. In most
+affected families the final outcome is usually total blindness. One of the
+most remarkable pedigrees of defects in man ever collected is one of this
+disease published by Nettleship. He succeeded in tracing the defect
+through nine generations, back to the seventeenth century. The genealogy
+includes 2,116 persons. The character behaves as a single dominant in
+males, but frequently, though not always, females may be carriers of the
+defect in transmissible form though not exhibiting it themselves. That is,
+males in which the condition is simplex (Aa) develop the defect but
+females of similar simplex constitution (Aa) frequently do not. It
+follows, therefore, that normal males of such strains will have normal
+offspring but normal females may have affected children.
+
+
+[Illustration: FIG. 24
+
+Radiograph (Courtesy of Dr. W. B. Helm) showing a partial syndactyly in
+each hand of an individual. Some degree of webbing between the more distal
+portions of the affected parts is usual.]
+
+
+[Illustration: FIG. 25
+
+Pedigree of a family with presenile cataract (black symbols); numbers in
+circles indicate unaffected individuals (after Davenport).]
+
+
+=Other Defects Inherited as Dominants.--=Not to go into details other
+defects which behave as dominants or modified dominants in human
+inheritance may be mentioned. The following list is not complete and it
+must be understood that in some cases the statistics are insufficient to
+justify us in making anything but a tentative decision. We may thus
+enumerate as dominant over normality: _Achondroplasy_ (abnormally short
+limbs with normal head and body); _Keratosis_ (thickening of epidermis);
+_Epidermolysis_ (excessive formation of blisters); _Hypotrichosis_
+(hairless, toothless condition); _Diabetes insipidus_; _Diabetes
+mellitus_; ordinary (not Gower's) _muscular atrophy_; _Glaucoma_ (internal
+swelling and pressure of eye-ball); displaced lens; _Coloboma_ (open
+suture in iris); spottedness of hair-coat; and corneal opacity.
+
+As a final illustration of a serious malady in man which acts as a
+dominant in inheritance, let us take _Huntington's chorea_. Ordinary
+_chorea_, or St. Vitus' dance, a disorder characterized by involuntary
+muscular movements, is commonly though not always confined to children and
+usually ends in recovery, but _Huntington's chorea_ appears typically in
+middle life and is a much more dangerous malady. Fig. 26, p. 114,
+represents the family history of one of five cases which have been studied
+by Doctor Lorenz in the Mendota Hospital for the Insane. All charts which
+have been platted of this malady show it to be inherited as a dominant.
+This means that half of the children of an individual who carried the
+malady in the simplex condition, and all the children of one who carries
+it in the duplex condition, are probably marked for this terrible end. And
+the true horror of it can only be appreciated by one who has seen the last
+stages of the malady. The victim once in its grasp gradually becomes
+wrecked in mind and body; the muscular twitchings and disorders of
+movement continually increase and dementia progresses until at last death
+ensues. Fig. 27, p. 115, is another chart showing inheritance of
+_Huntington's chorea_. In still a third case at the Mendota Hospital, the
+gravity of the situation can be appreciated when one realizes that the
+patient is the father of ten children, ranging in age from one to
+seventeen and one-half years. The calamitous fact that this disease does
+not manifest itself usually until middle life makes it likely that these
+children will all reach maturity, marry and in turn probably produce
+offspring before the doomed members of the family realize their fate.
+
+
+[Illustration: FIG. 26
+
+Chart showing descent of _Huntington's chorea_ in the P---- family
+(courtesy of Dr. W. F. Lorenz). Squares represent male, circles female;
+shaded figures are choreic members of the family; partially shaded
+figures, slightly affected or very "nervous" members. The members of the
+last generation are for the most part still too young to show their
+condition. The cross indicates the individual in the asylum from whom the
+record was traced back.]
+
+
+CASES OF RECESSIVENESS IN MAN
+
+=Recessive Conditions More Difficult to Deal With Because They Are
+Frequently Masked.--=Coming now to the question of recessive conditions in
+man, we find that defects are more likely to be of recessive than of
+dominant type. Apparently normality usually means the presence of normal
+determiners and abnormality, the absence of some essential determiner. In
+the latter case, a unit-factor has seemingly been lost out in some way in
+the germ-plasm, and the product of such germ-plasm is therefore
+incomplete. As long as the loss is counterbalanced by the presence of a
+single determiner from the other line of ancestry, that is, as long as the
+simplex (Aa) condition prevails, the loss may not be in evidence, except
+in cases of incomplete dominance (taints, etc.), but any mating which
+permits of the production of the nulliplex condition will bring the defect
+to expression again.
+
+
+[Illustration: FIG. 27
+
+Chart showing inheritance of _Huntington's chorea_ in the R---- family
+(courtesy of Dr. W. F. Lorenz); 1, 2 have been patients at Mendota
+Hospital for the Insane; 3, died of "paralysis"; the fourth or last
+generation indicated by the cross, ranging in age from 6 to 14, are too
+young yet to show their condition as regards this malady.]
+
+
+The obscure nature of recessives makes such conditions more difficult to
+deal with than dominant defects. For as regards the latter we have seen
+that marriage of unaffected members of the family as far as that
+particular trait is concerned, is perfectly safe, even to a cousin, for
+once the germ-plasm is purged of such a positive factor, it, in so far as
+we know, remains pure. But in the case of a recessive character due to the
+absence of some necessary determiner a normal offspring of simplex
+constitution (Aa) will probably transmit to half of his children the
+capacity for handing on the defect, or if mated to another normal
+individual of simplex constitution (Aa) is likely to have the actual
+defect revealed again in one-fourth of his children and latent in
+two-thirds of the remainder.
+
+=Albinism a Recessive.--=As an easily understood illustration of this type
+of case we may take human albinism, a condition which is due to the
+absence of a pigment-developing determiner. According to Davenport the
+albinic condition is recessive to normal condition. If albino (aa) is
+mated with albino (aa) nothing but albino children may be expected. An
+albino (aa) mated with a normal individual will have normal offspring
+(Aa), but they will have the capacity for transmitting albinism to their
+descendants. Thus the normal offspring (Aa) of an albino (aa) and a normal
+parent (AA) if mated to another normal individual (Aa) who has also had an
+albino parent will probably transmit actual albinism to one-fourth of his
+children and the same capacity that he himself has of producing albinos,
+to one-half of his children, although the latter will appear to the eye to
+be normal.
+
+=Other Recessive Conditions in Man.--=If for albinism we substitute
+certain forms of insanity, hereditary feeble-mindedness (Fig. 28, p. 118),
+or hereditary epilepsy, all of which apparently follow the same law, we
+can readily understand how unfit such matings are where both strains are
+affected. Marriage with similarly defective stock will result in the
+affection appearing in one-fourth of the progeny, and one-half of them,
+though apparently normal themselves, will have the capacity for
+transmitting the imperfection. It is in the existence of such hidden
+factors that the chief danger in the marriage of cousins, or in fact any
+consanguineous marriage lies.
+
+A few of the various defects which seem to be inherited as recessives when
+mated with normality are: susceptibility to cancer; _chorea_ (St. Vitus'
+dance); true dwarfism (all parts proportionately reduced); _Alkaptonuria_
+(urine darkens after passage); alcoholism and criminality, where based on
+mental deficiency; hereditary _hysteria_; _multiple sclerosis_ (diffuse
+degeneration of nervous tissue); _Friedreich's disease_ (degeneration of
+upper part of the spinal cord); _Merriere's disease_ (dizziness and
+roaring in ears); _Thomsen's disease_ (lack of muscular tone); hereditary
+_ataxia_; possibly the tendency to become hard of hearing with increased
+age; and possibly, non-resistance to tuberculosis.
+
+Of non-pathological conditions in man which are inherited as recessives,
+apparently either very great or very small intellectual ability are
+examples.
+
+
+[Illustration: FIG. 28
+
+Chart showing descent of feeble-mindedness as a typical recessive (after
+Goddard). Squares represent males, circles females; DD, homozygous
+dominant; DR, heterozygous dominant (i. e. normal although a carrier); RR,
+pure recessive; N, normal; F, feeble-minded; A, alcoholic.]
+
+
+=Breeding Out Defects.--=Even though recessive defects occur in a stock,
+there is the possibility of diluting out the imperfection in successive
+generations if care is taken always to marry into a stock wholly free from
+it. For example, a normal individual carrying a recessive defect will bear
+the abnormality in half of his or her germ-cells. This means that when
+such an individual marries a normal, non-carrier, half of their children
+will be wholly normal (AA) and half will be carriers; normal but of
+simplex constitution (Aa). If now this generation, carriers and
+non-carriers, marry only into normal strains of duplex constitution, then
+their combined issue will be likewise normal with only one-fourth of them
+carriers of the imperfections. This means that even if all of this last
+generation were married to persons having the defect only one out of four
+would have children showing it although the remaining children would be
+carriers. On the other hand if mated to normals only one-eight of the next
+generation would be carriers. Thus by continually marrying into strong
+strains liability to manifest any recessive defect can be diminished in a
+few generations until the descendants are no more likely to have defective
+children than are members of our ordinary population.
+
+The proportion in which the recessive defect would appear in successive
+generations if all persons in a given generation married only normal
+individuals who were non-carriers is indicated in the following table
+where AA indicates a normal individual, Aa one who is normal but a
+carrier, and aa an individual with the imperfection expressed; to indicate
+proportions simply after the first generation, four is arbitrarily chosen
+as the number of children which results from each marriage:
+
+                  Matings   Children
+  Generation 1    aa × AA = Aa
+
+  Generation 2    Aa × AA = 2AA + 2Aa
+
+  Generation 3    AA × AA = 4AA
+                  AA × AA = 4AA
+                  Aa × AA = 2AA + 2Aa
+                  Aa × AA = 2AA + 2Aa
+                           ----------
+                           12AA + 4Aa
+
+=Other Inheritable Conditions in Man.--=While many pedigrees show beyond
+dispute that such qualities as musical ability, literary ability, memory,
+calculating ability, mechanical skill, longevity, peculiarities of
+handwriting, obesity and muscular strength, for example, are inherited,
+their modes of inheritance have not yet been sufficiently analyzed to
+express them exactly.
+
+
+
+
+CHAPTER V
+
+ARE MODIFICATIONS ACQUIRED DIRECTLY BY THE BODY INHERITED?
+
+
+=Which New Characters Are Inherited?--=Any new feature which appears in a
+given organism may have had its origin in some change which has come about
+in the germ from which it sprang, or it may be merely the product of some
+unusual stimulus operating on the body. While the outcome, as far as the
+present individual is concerned, is in each case a definite modification,
+the matter of inheritance is a very different question. On the first
+alternative where the new character is the outcome of germinal change, it
+is obvious that the altered germ-plasm will find expression in a similar
+way in succeeding generations as long as the new germinal combinations
+persist. On the other hand, if the new character has resulted merely from
+some influence operating on the body of the individual, then to be
+inherited it would also have in some way to be transferred to and
+incorporated in the germ-plasm. Inasmuch as the body or soma of any
+individual is highly plastic and since various of its ultimate features
+may be mere somatic modifications, it is important to decide if possible
+whether or not somatic variations which are not of germinal origin can be
+inherited.
+
+=Examples of Somatic Modifications.--=For example, the small foot of the
+Chinese woman of certain caste is the result of inherent germinal factor
+for the production of a foot plus the effects of binding which are in no
+wise germinal. The hand of the skilled pianist is a normal hand of
+germinal origin and normal environment plus the effects of special
+training. Again, the head of the Flathead Indian is a normal head of
+germinal origin and environment plus the effects of flattening. Similarly,
+almost any malformation of extrinsic origin may be cited, ranging from
+mutilations and amputations, scars and the like to monstrosities such as
+one-eyed fish which may be produced by subjecting a developing embryo to
+adverse conditions of development.
+
+=Use and Disuse.--=Even reactions set up through the organism's own
+activities must produce changes. For example, a muscle has a certain
+average of normal development in the average man; it comes to this through
+the innate nature of its component cells plus a certain average amount of
+exercise. It may, however, be developed far beyond this average by
+excessive exercise. On the other hand, it is a well-known fact that an
+unused organ weakens or may remain but partially developed. Thus either
+use or disuse may play an important part in the molding of a given
+individual. But whether or not in doing this it similarly affects the germ
+is a very different matter.
+
+=The Problem Stated.--=The question is can such enhanced or suppressed
+development, or can new or modified characters, produced in an individual
+by external agencies be so reflected on the germ-cell of the individual
+that they tend to reappear _as such_ in its offspring without requiring
+the same external factors for their production?
+
+=Special Conditions Prevail in Mammals.--=Before proceeding further we
+must recognize clearly the very special conditions which exist in most
+mammals. With them environment is in part an intra-maternal environment
+and in part independent of parental influences. Thus the formula for most
+non-mammalia would be--
+
+  Individual == egg + non-parental environment; but
+
+for most mammals, including man--
+
+  Individual == egg + intra-maternal environment + non-parental
+  environment.
+
+This condition in mammals introduces a complicating factor which is likely
+to obscure the whole issue unless we bear it constantly in mind. In other
+words, we must discriminate sharply, in the discussion of inheritance in
+man, for instance, between two classes of influences which may exist in
+the infant at birth, that is, which are _congenital_; namely, those which
+were truly inherent--were in the germ-cells--at the very inception of the
+young individual, and (2) those which might later have been derived from
+either parent by the yet unborn offspring. The latter are not regarded as
+truly hereditary. Since certain diseases or their effects belong here we
+occasionally find a physician using the term inheritance for such prenatal
+influences, but the more careful ones now employ the term _transmission_
+to discriminate between such conditions and true inheritance. In its
+biological usage inheritance always refers to germinal constitution and
+never to any condition that may be thrust on a developing organism before
+birth. It is clear, then, that congenital conditions are not all
+necessarily cases of inheritance.
+
+=Three Fundamental Questions.--=To get at the question of the inheritance
+of body modifications with the least confusion, let us examine it in the
+form of three fundamental questions, as follows:
+
+1. Can external influences directly affect the germ-cells?
+
+2. Can external influences, operating through the intermediation of the
+parental body, affect the germ-cells? If so, is the effect a specific and
+a permanent one which persists in succeeding generations independently of
+external influences similar to those which originally produced it? Only
+such a condition as this would rank as the inheritance of a somatic
+modification.
+
+3. Can the appearance of new characters be explained on any other ground,
+or on any more inclusive basis, than through the transmission of somatic
+acquirements, or do organisms possess heritable characters which are
+inexplicable as inheritance of such modifications?
+
+Obviously the only way the question can be settled is through careful
+experimentation in which all possible sources of error have been foreseen
+and guarded against. Much experimental work has been undertaken for the
+solution of this problem as the goal and we may therefore select typical
+ones of these experiments and apply the results toward answering our three
+questions.
+
+=External Influences May Directly Affect the Germ-Cells.--=There is
+evidence that under special conditions external influences may in certain
+organisms affect the germ-cells, but that this occurs commonly is
+extremely doubtful. For example, Professor MacDougal, by treating the
+germ-cells of the evening primrose with various solutions, such as sugar,
+zinc sulphate and calcium nitrate, has apparently succeeded in producing
+definite germinal mutations. He injected the solution into the ovary of
+the flower the forenoon of the day at the close of which pollination would
+occur. He reports that in this way changes were produced in the germ which
+found expression in new and permanent characters.
+
+Professor Tower has experimented for a number of years with various
+species of _Leptinotarsa_, the potato beetle. By varying the conditions of
+temperature, humidity and atmospheric pressure when females were laying
+their eggs, he reports having produced variations in the young which came
+from these eggs although the mothers themselves were not changed.
+According to Professor Tower slight increase or decrease in these
+environmental factors stimulated the activity of the color producing
+ferments, giving rise to melanic or darker individuals. Greater increase
+or decrease, inhibited them and produced albinos. He found also that at
+times the same stimulus might show different results in different eggs.
+The effect, therefore, is a general and not a specific one. Ordinarily the
+eggs of these beetles are laid in batches. When one of these batches was
+laid and left under normal conditions, the usual form of young hatched
+from it, but other batches from the same female under abnormal conditions
+resulted in the production of atypical forms. For example, a normal
+two-brooded form became five-brooded. The commonest modification was the
+production of various color types. These once established, according to
+Professor Tower, behave as independent, inheritable units.
+
+The experiments of Doctor Bardeen with X-rays and of others with X-rays,
+radium and other agents on the sperm and ova of amphibia show that these
+are very susceptible to injurious influence at or near the time of
+fertilization.
+
+=Such Effects Improbable in Warm-Blooded Animals.--=However possible it
+may be to bring about germinal changes in invertebrata or lower vertebrata
+by such external agents as temperature and the like it is obvious that the
+probability of such extrinsic influences affecting the germ-cells of
+warm-blooded animals is very remote indeed. In the latter the germ-cells
+are more or less distant from the exterior and are at practically a
+constant temperature. Such experiments, therefore, beyond showing the
+possibility of producing changes in germ-cells, do not have very direct
+bearing on the problem of how inheritable variations are produced in man.
+In his case about the only avenue of approach through which germ-cells
+might be influenced is the blood or lymph.
+
+=Poisons in the Blood May Affect the Germ-Cells.--=Any poisonous material
+in the latter might injuriously affect the gametes. We know, in fact, that
+such poisons as alcohol, lead and various drugs, and also the toxins of
+various diseases, do so affect germ-cells. It seems plausible to suppose
+that changing conditions of nutrition may affect the constitution of the
+germ-cells and thus induce changes in the organism which arise from these
+cells, but such nutritional effect is not yet a matter of established
+fact.
+
+=Difficulty of Explaining How Somatic Modifications Could be Registered in
+Germ-Cells.--=As to our second query concerning the possibility of
+affecting the germ-cells through the intermediation of parental tissues,
+it is evident at a glance that since the germ-cells are built up along
+with the body and are not a product of it (Fig. 2, p. 13), if such effects
+are possible they must take place through the agency of some transporting
+medium. The germ-cells, being lineal descendants of the original fertile
+germ or zygote, already have the same possibilities of developing into an
+adult that the zygote had, and so the problem becomes one of modifying a
+complete germ already organized rather than of establishing a new germ by
+getting together samples of every part of the body. This is all the more
+evident when one realizes that usually the germ-cells are set apart long
+before the body becomes adult, that is, before the body has developed most
+of its characteristics. Moreover, among lower animals many instances are
+known where the immature young or even larvæ will produce offspring which
+nevertheless ultimately manifest all the structures of the adult
+condition.
+
+But supposing specific modifications of the germinal mechanism were
+possible, it is difficult to comprehend how an influence at a distant
+point of the body could reach the germ-cell, to say nothing of the even
+greater difficulty of understanding how it could become registered in the
+germ in a specific way as affecting a particular part. For it must be
+remembered that the organs of the adult do not exist as such in the germ
+but are present there only as potentialities. How, for example, can a
+change in the biceps muscle of one's arm be registered in a germ-cell in
+which there is no biceps muscle, but merely the possibilities of
+developing one? Or how can increased mental ability which is contingent on
+the elaboration of certain brain-cells be impressed on a germ which has no
+brain-cells but only the capacity under certain conditions of producing
+such cells? For the brain of a child is not descended from the brain of
+his parent, but from a germ-cell carried by that parent.
+
+=Persistence of Mendelian Factors Argues Against Such a Mode of
+Inheritance.--=On the face of things, the apparent inviolability of
+Mendelian factors which may remain unexpressed in the germ for one or many
+generations--indeed the whole matter of genotypical differences in the
+gametes of the same individual--shows the improbability of somatic
+interference with the germ-plasm. But notwithstanding this, because of the
+great importance of the issue, it is well to review in some considerable
+detail the various phases and possibilities of the question.
+
+=Experiments on Insects.--=Some of the attempts to secure evidence of the
+transmission of personally acquired parental modifications in insects are
+very interesting. Many insects in the larval stages, particularly just
+after pupation seem to be especially susceptible to external influences.
+They have been much used, therefore, for purposes of experiment. It has
+long been known that differences in size, in color and even in the shape
+of wings can be produced by various agents if applied at this period of
+development. From the standpoint of heredity, however, the important
+consideration is to determine if these experimentally induced changes have
+been reflected on to the germ-cells so that they reappear in the offspring
+of the modified individuals.
+
+It has been found that in some cases where male and female are of
+different color, the color of the female can be changed to that of the
+male by altering the conditions of temperature. In certain cases types can
+be changed by cold so that they resemble varieties of the same species
+found farther north, and by heat, varieties found farther south. But not
+all individuals of a given lot are affected, and often different
+individuals of the same kind show different effects. Moreover, in some
+cases the same aberrations were produced by heat as by cold. This
+indicates that it is not so much a question of specific effects as a
+general physiological change, apparently mainly a matter of direct
+influence of temperature on the chemical composition of the pigments. The
+Countess von Linden in fact has shown that the extracted pigments can be
+made to undergo the same changes of color in a test-tube by heat and cold
+as in the pupæ. But there is no evidence that the germ-cells of the living
+insect were affected in a specific way. In a small fraction of the
+offspring of such modified individuals abnormalities appeared, but these
+were not always of the same kind as those which had been produced in the
+parent. That is, there was no evidence of a trait or character having been
+acquired by the body and handed on to the germ-cell. Where an effect was
+produced on the germ-cell it was probably produced directly as in the
+first cases discussed.
+
+Size, colors and markings of butterflies have also been altered by
+subjecting the caterpillars or the pupæ to such influences as strong
+light, electricity, various chemical substances, centrifuging, diminished
+oxygen supply, etc., but the results were in the main confined to the
+immediate generations. In the few cases where permanent inheritable
+changes were seemingly produced they were more reasonably interpreted as
+the effects of direct action on the germ-cells than as examples of
+inherited somatic modifications.
+
+Starvation experiments which resulted in the dwarfing of adult individuals
+have been performed on various insects, and while the dwarf condition may
+persist through one or two generations due to a diminished food supply in
+the eggs of the dwarf, the stock in question when returned to normal food
+conditions soon resumes its original characteristic size.
+
+=Experiments on Plants.--=Many experiments have been performed with
+plants, inasmuch as they are particularly prone to become modified by
+changes of food supply, or climate. For example, plants which grow
+luxuriantly in a warm moist climate or a rich soil may become stunted and
+markedly changed if transplanted to a cold climate or a poor soil.
+Naturally, their progeny will exhibit the same behavior as long as they
+are kept under the new conditions. Experiments carried on through numerous
+generations, however, practically all show that the germinal constitution
+of the plants remains unchanged, for when their seeds are planted under
+the original favorable conditions of soil or climate, the plants resume
+their former habits of growth. Naegeli, for instance, who made a study of
+many varieties of Alpine plants, and who carried on experiments with many
+of them for years in the Garden of Munich, concluded that no permanent
+effects had been produced by the Alpine climate and conditions in plants
+from other regions which had come under its influence. A few botanists
+have claimed to have found that the changes produced by the Alpine climate
+have persisted for a generation or two and have then worn off. More recent
+experiments on various of our field grains which have been stunted and cut
+down in productivity by growing for a number of generations under adverse
+conditions show that they have not been permanently modified by such
+treatment, for they resume normal productivity and size when grown again
+under favorable conditions.
+
+On the other hand, Lederbaur found that a common weed, _Capsella_, when
+transplanted from an Alpine habitat to the lowlands did not return to the
+lowland type of the weed, but retained certain of its Alpine
+characteristics. It is not clear, however, that this particular species
+during its long sojourn of many generations in Alpine conditions may not
+have undergone a series of germinal variations and have developed into a
+new variety or species quite independently of changes wrought in the germ
+by reflected somatic effects. Indeed, in face of the preponderance of
+other cases to the contrary, this interpretation would seem to be the more
+plausible one.
+
+=Experiments on Vertebrates.--=In the vertebrates we may also find
+examples of various somatic modifications experimentally produced, but
+evidence of their inheritance is as difficult to establish as in the
+invertebrates. Let us examine a few of the more significant of these which
+are alleged by some to bear evidence of such inheritance.
+
+By decreasing the amount of water in an aquarium Marie von Chauvin was
+able to transform the aquatic, gill-breathing salamander _Axolotl_ into
+the gill-less land form _Ambystoma_, heretofore regarded by systematists
+as a different species. Either of these forms when sexually mature
+produces its like. The salamanders in question have both lungs and gills,
+but after a time the ones which are to be land forms lose their gills and
+become exclusively lung-breathers. What seems to have been accomplished
+then is the accelerating or forcing of normal natural tendencies already
+inherent in the organism instead of introducing something new into the
+inheritance by way of the soma. _Axolotl_ is in all probability merely a
+larval form of _Ambystoma_ which with high temperature and an abundance of
+water reproduces without advancing to the final possible stage of its life
+cycle.
+
+=Epilepsy in Guinea-Pigs.--=Perhaps the most frequently cited case and the
+one in which the defenders of the idea of somatic inheritance usually take
+final refuge is that of Doctor Brown-Sequard's guinea-pigs,
+notwithstanding the fact that no one has had convincing success in
+repeating the experiments and that the original results are apparently
+open to more than one interpretation. This experimenter rendered
+guinea-pigs epileptic by certain injuries to the nervous system. Epilepsy
+appeared in some of the offspring of these operated animals. He regarded
+this as an example of the inheritance of an artificially induced epilepsy.
+An indirect loss of toes occurred in some of the parents as a result of
+the operations on the nervous system. Some of their young also had missing
+toes. However, as has been pointed out by various critics, guinea-pigs are
+strongly predisposed toward epileptic-like seizures, and the epilepsy in
+the young may have been merely a coincidence. Voison and Peron believe
+they have shown that in epilepsy a toxin is produced that may affect the
+unborn fetus. That is, the result might have been due to a poison derived
+directly from the mother. The experiments in fact show that it was mainly
+in the offspring of affected mothers that the condition appeared. Others
+maintain that we do not know the exact nature of epilepsy, that in some
+cases it may be the result of infection by disease-germs, and that
+Brown-Sequard's cases may, therefore, have been merely the communication
+of a disease from parent to child. As to the disappearance of toes it is a
+well-known fact that rodents in particular are likely to gnaw off the toes
+of their young very soon after birth, and little credence can be put in a
+lack of toes in such young as cases of inheritance except under conditions
+of much more careful observation than existed in Brown-Sequard's
+experiments. A fuller account of these experiments will be found in
+Romanes' _Darwin and After Darwin_, Vol. II, Chap. 6.
+
+=Effects of Mutilations Not Inherited.--=Many experiments have been
+performed by investigators to determine whether or not the results of
+mutilation are transferred to succeeding generations, but so far only with
+negative results. Many such experiments have been unwittingly carried on
+for many generations, in fact, by breeders and fanciers, in the docking of
+horses, dogs and sheep, the dehorning of cattle and the like, yet no
+satisfactory evidence of the transmission of such conditions in any degree
+has ever been forthcoming. The mutilations or distortions of the human
+body through various rites or social customs also fails to yield any
+convincing examples. Foot-binding, head-binding, or waist-binding must be
+repeated in each successive generation to produce the particular type of
+"beauty" that results from such deformities. And lucky it is for man that
+injuries do not persist in subsequent generations, otherwise the modern
+human being would be but a maimed relic of past misfortunes.
+
+=Transplantation of Gonads.--=An interesting experimental test regarding
+the effect of the body on the germ was made recently by Castle and
+Phillips with guinea-pigs. It will be recalled from the discussion on
+Mendelism that when a black guinea-pig is mated with a white one the
+offspring are always black. These experimenters transplanted the ovaries
+from a young black guinea-pig to a young white female whose own ovaries
+had been previously removed. This white female was later mated to a white
+male. Although she produced three different litters of young, six
+individuals in all, the latter were all black. That is, not a trace of
+coat-color of the white father or of the white foster-mother was impressed
+on the transplanted germ-cells or the developing young. Later experiments
+of the same kind by Castle and Phillips, with other varieties of
+guinea-pigs, have yielded the same results. The body of the mother,
+indeed, seems to serve merely as a protective envelope and a source of
+nutrition.
+
+=Effects of Body on Germ-Cells General, Not Specific.--=As far as the
+evidence regarding the modification of the germ-plasm by the body is
+concerned, we must conclude then that while under special circumstances
+the germ-cells may be affected, the effect is general rather than specific
+and the result as seen in the offspring has no discoverable correlation
+with any particular part or structure of the parental soma. The effect is
+presumably of much the same nature as where the germ is directly affected
+by external agents. Where a new character or a modification of one already
+existing is produced by a given condition of environment, in our
+experience so far to have the same repeated in the offspring, a similar
+evocative condition must prevail in the environment of the latter. Or in
+other words the new character is not a permanent one which persists in
+succeeding generations independently of external influences similar to
+those which originally produced it.
+
+=Certain Characters Inexplicable as Inherited Somatic Acquirements.--=It
+would require remarkable credulity, in fact, to believe that some of the
+most striking features about certain plants or animals could have been
+developed by means of the inheritance of somatic modifications. For
+example, many animals such as the quail, the rabbit, or the leaf-butterfly
+are protectively colored. That is, they harmonize in color-pattern with
+their surroundings so closely that they are overlooked by their enemies.
+But how can this oversight on the part of an enemy so affect the bodies
+and through them the germ-cells of such individuals as to develop so high
+a degree of protective coloration? Or how, indeed, could any of numerous
+adaptive structures which one can think of, such as the color or scent of
+flowers to lure insects for cross-pollenation, the various grappling
+devices on many seeds to secure wide distribution by animals, or the like,
+have been directly produced by use or disuse or by any variation produced
+in them by the agents to which they are adapted?
+
+=The Case of Neuter Insects.--=A very instructive example of the
+improbability that great skill, highly specialized structures, or certain
+instincts are first developed in the parental body as the result of use
+and then passed on to the offspring, is seen in the case of neuter
+insects. In bees, for example, there are three classes of individuals: the
+drones or males; the queens or functional females; and the workers, which
+are neuter, that is, take no part in reproduction. The latter are really
+sexually undeveloped females. The queen can lay either fertilized or
+unfertilized eggs. The latter always give rise to males. The workers
+gather the food, attend the queen, wait on the young, construct the comb,
+and in short perform all the ordinary functions of the colony except the
+reproductive. They have many highly specialized structures on various
+parts of their bodies for carrying on their many activities, as well as
+the very highly specialized instincts necessary to the maintenance of the
+colony. But now, complex and highly developed as these workers are, since
+they do not give rise to offspring, no matter how much experience or
+structural modifications they may acquire during their lifetime, it can
+not be handed on to another generation. Nor can they have come to their
+present highly organized state through such a form of transmission since
+they are not the descendants of workers but of a queen. Any new
+modifications that appear in the workers of a colony must therefore have
+their origin in changes which have taken place in the germ-cells of the
+queen, and not in the soma of some other worker. It has been argued that
+the worker has not always been infertile; that at a more primitive stage
+of the evolution of the bee colony every female was both worker and
+mother, and that individual somatic acquirements might therefore have been
+transmitted, but this argument can not hold for many of the instincts or
+features of the modern bee because these have to do only with the
+conditions of life which exist in the colony in its present form. It is
+obviously absurd to maintain, for instance, that all the highly
+specialized instincts incident to queen production, queen attendance and
+the like were functionally produced through usage before there was any
+queen to produce or attend, while on the other hand, the very necessity of
+queen production and maintenance is the outcome of the infertility of the
+workers. Some workers have been known to lay eggs, but as these are few in
+number and are never fertilized, which means if they develop they can only
+produce males, they can play no considerable part in inheritance.
+
+
+ORIGIN OF NEW CHARACTERS
+
+=Origin of New Characters in Germinal Variation.--=This brings us to our
+last query as to whether the appearance of new characters can be explained
+on any other or any more inclusive ground than that which infers that
+changes undergone by the parent-body are in some way registered in the
+germ-cells so as to be repeated in a certain measure in the body of the
+offspring. The answer to the question of how inheritable variations do
+come to appear in offspring if not through changes produced in the body of
+the parent, is uncertain; nevertheless most biologists believe that they
+do not have such a somatic origin but arise directly as germinal
+variations. Some would attribute them to the fluctuating nature of living
+substance in general. The instability of protoplasm is one of its striking
+characteristics. It is constantly being broken down and built up, or, in
+other words, undergoing waste and repair. Like all other protoplasm, that
+of the germ-cells must also undergo these metabolic changes and it is
+possible though not proved that in this give and take of substances small
+changes occur in their constitution which find expression in the offspring
+as variations. As already seen, substances in the blood other than food
+may also affect the constitution of the germ-cells.
+
+=Sexual Reproduction in Relation to New Characters.--=Some biologists
+attribute great importance to sexual reproduction as a basis of variation
+and the origin of new characters. They argue that the mingling of
+determiners from two different lines must produce many new combinations
+and expressions of germinal potentialities. Plausible as the argument
+seems at first sight no one has succeeded as yet in securing proof that
+absolutely new characters can be originated in this way. What seems to
+occur under such circumstances is merely a reshuffling or sorting of old
+unit-characters. Although innumerable permutations and combinations of
+these may be made which find new expression outwardly, this is obviously
+not creating determiners of new unit-characters in the germ-plasm. While
+many biologists would not deny the possibility or even the probability
+that the determiners of unit-characters may sometimes combine or influence
+one another so as to form actual permanent new characters, the proof of
+such performance is wholly lacking. On the other hand, there are not a few
+biologists who argue that sexual reproduction accomplishes just the
+reverse of increasing the extent of variation or creating new characters;
+according to them it tends to annul exceptional peculiarities of either
+parent by throwing the offspring back to the average racial type. It is
+thus looked on by these advocates as a stabilizer which reduces the
+amplitude of variations instead of increasing them. As a matter of fact
+the two ideas are not mutually exclusive; sexual reproduction may
+accomplish both of these ends. A limited number of observations and
+experiments have been made to test out the correlation between sexual
+reproduction and variation, but they have so far been too few or too
+inconclusive to enable us to come to a satisfactory conclusion.
+
+While we are uncertain about the method of origin of new characters the
+fact remains that they do arise in abundance as abrupt mutations or
+otherwise and become a part of the permanent heritage of a stock. It is
+clear that sexual reproduction may be one important means by which a given
+new character which has arisen in one or a few individuals may become
+incorporated in the species at large. Through Mendelian combinations and
+segregations it would by cross-breeding be spread and gradually introduced
+into more and more strains of the general population.
+
+=Why So Many Features of an Organism Are Characterized by
+Utility.--=Germinal variations are seemingly at first more or less hit or
+miss affairs as far as utility to the organism is concerned. Useless
+variations, so long as they are not actually harmful, may persist and
+apparently be indefinitely inherited. However, a special premium is put on
+variations which happen to be useful for they help the organism to succeed
+in its struggle for life and since success in the world of life means not
+only mere individual survival but also the production of progeny, through
+this very means insured transmission to subsequent generations. It is
+probable that the very many useful features of any organism, that is, its
+_adaptations_, have thus been established. It is possible also that many
+variations which at their inception are indifferent may wax in strength in
+successive generations until they reach a point where they must become
+either useful or harmful. In the former case they would mean increased
+insurance of survival for their possessors, in the latter, elimination.
+With such an automatic process as this operative in nature it is not
+astonishing that the main features of any organism are characterized by
+their utility to it.
+
+=Germinal Variation a Simpler and More Inclusive Explanation.--=The gist
+of the whole matter regarding the source of new characters in offspring
+seems to be that the explanation based on the idea of germinal variation
+is in last analysis the simpler and more inclusive, and there is no
+alleged case of inheritance of parental modification, which can not be
+equally well explained as the result of a germinal variation. There are
+numerous cases which can not be explained as transmissions of somatic
+acquirements even if this transmission could be established in certain
+cases. So, many biologists argue, why have two explanations when one is
+sufficient, especially when the other has never been conclusively
+established as true in any case and is obviously untrue in certain test
+cases? The attitude of most investigators is that of the open mind. While
+feeling that the weight of probability is very decidedly against the
+theory of the inheritance of somatic modifications, they still stand ready
+and willing to accept any evidence in its favor which when weighed in the
+balance is not found wanting.
+
+
+ANALYSIS OF CASES
+
+While space will not permit extended discussion, in order further to fix
+the nature of the problem in mind as well as to exemplify the conditions
+that must be satisfied to form convincing evidence of inherited somatic
+acquirements, it will be well perhaps to analyze a few typical cases as
+they are frequently cited.
+
+=Are the Effects of Training Inherited?--=Breeders and trainers very
+commonly believe that the offspring of trained animals inherit in some
+measure the effects of the training. Thus the increased speed of the
+American trotting horse is often pointed to as strong evidence of such
+transmission. According to W. H. Brewer, the earliest authentic record of
+a mile in three minutes was made in 1818. The improvement, approximately
+by decades, from that time was as follows:
+
+  During 1st decade after 1818, improved to 2:34
+         2nd   "      "    "       "     "  2:31-1/2
+         3rd   "      "    "       "     "  2:29-1/2
+         4th   "      "    "       "     "  2:24-1/2
+         5th   "      "    "       "     "  2:17-1/2
+         6th   "      "    "       "     "  2:13-1/2
+         7th   "      "    "       "     "  2:08-1/2
+
+By 1892, the date of Professor Brewer's publications (See _Agricultural
+Science_, Vol. 4, 1892) the record had reached 2:08-1/2. Since then it has
+been lowered still further.
+
+On the face of it this looks like a good case of inheritance of training,
+and Brewer himself believed it such. If so this would mean that colts of a
+highly trained trotter would be faster than they would have been if their
+parent had remained untrained. It is impossible to get positive proof in
+the case of any trained horse since there is no way of establishing just
+how speedy the progeny would have been had the parent remained untrained.
+If it could be shown that colts sired by a trotter late in life were on
+the whole faster than those sired by the same father when younger and as
+yet not highly exercised in trotting, then the facts might give some
+evidence of value, but unfortunately no such records are available.
+
+On the other hand, even ignoring the fact that improvement in track and
+sulky are probably the biggest items in the shortening of records in
+recent times, _selection_ instead of inheritance of the effects of
+training will equally well account for any innate progress in trotting.
+And since, as pointed out by Professor Ritter, there are even more
+striking cases of similar improvements in other fields, such as college
+athletics, where the factor of use-inheritance is entirely precluded, it
+is wholly unnecessary to postulate it in the case of the trotter.
+
+For example an inspection of the records of college athletics for the last
+thirty-five years in running, hurdling, pole-vaulting, jumping, putting
+the shot, etc., shows on the whole a steady advance year by year.
+Moreover, the greatest improvement has occurred in those events in which
+skill and practise count for most together with selection of the
+inherently ablest candidate for the events. But in the case of athletics
+the improvements shown in thirty-five years have all come within a single
+generation and hence the inheritance of the effects of training is ruled
+out as a factor. Selection and improved training are the only factors
+operative.
+
+In the case of the trotter inheritance undoubtedly has also been a factor,
+but inheritance based on selection of what the race-track has shown to be
+the speediest individual, not inheritance of the effects of training. In
+other words, horses which have shown the capacity for being trained to the
+highest degree of speed have naturally been selected as sires and dams
+and so through selection generation after generation a speedier strain has
+gradually been established.
+
+=Instincts.--=When we turn to the realm of mental traits, particularly of
+instincts, we meet with a whole host of activities which are frequently
+pointed to by transmissionists as examples of inherited acquirements. Thus
+according to them, habits at first acquired through special effort
+ultimately become instinctive, or according to some, instinct is "lapsed
+intelligence." Instances often cited are the pointing of the bird-dog, the
+extraordinary crop-inflation of the pouter-pigeon, or the tumbling of the
+tumbler pigeon. We can not stop to discuss these cases beyond pointing out
+as many others have done that practically all dogs have more or less of an
+impulse to halt suddenly, crouch slightly and lift up one fore-foot when
+they scent danger or prey, that all pigeons pout more or less, and that
+practically all show more or less instincts of tumbling when pursued by a
+hawk. Thus in all of these cases the fundamental germinal tendency is
+already at hand for the fancier to base his choice on and thus through
+selection build up the type desired. Just as in the fan-tailed pigeon, by
+repeatedly selecting for breeding purposes individuals which showed an
+unusual number of tail-feathers he has built up a type with an upright,
+fan-like tail having many more feathers than the twelve found in the tail
+of the ordinary pigeon, so by similar procedure in the case of other forms
+he has markedly enhanced certain features. The idea of instincts being
+"lapsed intelligence" is so clearly and concisely criticized in an
+article by the late Professor Whitman[4] that I can not do better than
+quote an excerpt. His views to the contrary are as follows:
+
+    "The view here taken places the primary roots of instinct in the
+    constitutional activities of protoplasm and regards instinct in every
+    stage of its evolution as action depending essentially upon
+    organization. It places instinct before intelligence in order of
+    development, and is thus in accord with the broad facts of the present
+    distribution and relations of instinct and intelligence, instinct
+    becoming more general as we descend the scale, while intelligence
+    emerges to view more and more as we ascend to the higher orders of
+    animal life. It relieves us of the great inconsistencies involved in
+    the theory of instinct as "lapsed intelligence." Instincts are
+    universal among animals, and that can not be said of intelligence. It
+    ill accords with any theory of evolution, or with known facts, to make
+    instinct depend upon intelligence for its origin; for if that were so,
+    we should expect to find the lowest animals free from instinct and
+    possessed of pure intelligence. In the higher forms we should expect
+    to see intelligence lapsing more and more into pure instinct. As a
+    matter of fact, we see nothing of the kind. The lowest forms act by
+    instinct so exclusively that we fail to get decided evidence of
+    intelligence. In higher forms not a single case of intelligence
+    lapsing into instinct is known. In forms that give indubitable
+    evidence of intelligence we do not see conscious reflection
+    crystallizing into instinct, but we do find instinct coming more and
+    more under the sway of intelligence. In the human race instinctive
+    actions characterize the life of the savage, while they fall more and
+    more into the background in the more intellectual races."
+
+For further discussion of this field the reader is referred to an
+excellent chapter on "Are Acquired Habits Inherited?" in C. Lloyd Morgan's
+book, _Habit and Instinct_.
+
+=Disease.--=Perhaps in the realm of disease more than in any other has an
+interest in the inheritance of somatic acquirements been manifested. The
+problem arising here is not essentially different from other questions of
+inheritance but since it is a matter of such practical importance to man,
+we may well give it special attention. We have to deal simply with the old
+questions of what is constitutionally in the germ, what is acquired by the
+body, and lastly, whether the somatically acquired is inherited. While we
+all know in a general way what is meant by disease, especially if some
+specific disorder such as scarlet fever, malaria or tuberculosis is
+mentioned, an attempt to give an accurate definition is much like trying
+to define a weed, inasmuch as what is functionally all right at one time
+or place may be all wrong at another, or what is normal in one animal may
+be abnormal in another. In general we may say that disease is derangement
+or failure of physiological function.
+
+=Reappearance of a Disorder in Successive Generations Not Necessarily
+Inheritance.--=In attempting to study the inheritance of diseases we must
+recognize clearly at the outset that reappearance of a disease in
+successive generations by no means necessarily signifies inheritance.
+Before it can be pronounced such we must make sure that it is not a case
+of reimpressing similar modifications on the individuals of successive
+generations. For example, in England there is a well-recognized condition
+known as collier's lung which results from constant working in coal mines.
+And while both father and son may exhibit it, because of their similar
+occupations, there is nothing hereditary about the malady. Likewise there
+is what is known as emery grinder's lung, and practically every large
+manufacturing city with soot-laden atmosphere leaves its impress on the
+lungs of the inhabitants. This will occur, of course, generation after
+generation, as long as such pollutions of the atmosphere continue to
+exist. It is clear that any unhealthy occupation is likely to cause the
+reappearance of an associated typical disease generation after generation
+as long as the children follow the calling of their parents. The common
+misconception that deformities or postures associated with a trade, such
+as a shoemaker's or tailor's, is genetically stamped on offspring by the
+end of the third or fourth generation results from failure to discriminate
+between real inheritance and mere reappearances under similar conditions
+of environment.
+
+=Prenatal Infection Not Inheritance.--=Again, we must recognize that
+prenatal infection is not inheritance. We have already seen that the young
+mammal undergoes a certain period of intra-maternal development, but
+influences operating on it during this period of gestation must be
+reckoned with as environmental, not germinal. For example, it is said that
+an unborn child may take smallpox from its mother but this and all similar
+occurrences are cases of contagion. We find the great pathologist,
+Virchow, who with many others of his time was a believer in the
+inheritance of acquired characters, saying nevertheless regarding such
+instances that, "What operates on the germ after the fusion of the
+sex-nuclei, modifying the embryo, or even inducing an actual deviation in
+the development, can not be spoken of as inherited. It belongs to the
+category of early acquired deviations which are therefore frequently
+congenital."
+
+=Inheritance of a Predisposition Not Inheritance of a Disease.--=We must
+discriminate sharply also between the inheritance of a predisposition and
+the inheritance of a disease itself.
+
+We often hear the statement made that tuberculosis is inherited and have
+cited in evidence certain consumptive families or strains. But
+tuberculosis is a bacterial disease and children of tuberculous parents
+are never born with the disease except in the rarest of instances.
+
+=Tuberculosis.--=What is really inherited is a constitutional
+susceptibility to this particular germ. While almost any individual may
+contract tuberculosis when in a state of depressed vitality, or under
+stress of adverse surroundings, there is no doubt that certain families
+are more easily infected than others and much less resistant to the
+ravages of the disease when once it gains a foothold. However, a
+predisposition is a vastly different thing from the inheritance of the
+actual disease. For just as we are born with a nose well adapted to
+eye-glasses but not with eye-glasses on our nose, so many of us are born
+tuberculizable though not tuberculous, and every sanitary advance we make
+toward lessening the chances of infection is just so much more insurance
+for the susceptible.
+
+The whole problem of tuberculosis is an extremely complex one. We do not
+know just the measure of the inheritance of the predisposition. Some
+writers in the past have maintained that tuberculosis is mainly a question
+of infection and not of inherent susceptibility, but steadily increasing
+evidence all points the other way.
+
+Where the predisposition exists the chances of infection are still, even
+under the conditions of present-day sanitation, very great. The close
+association between a consumptive and other members of the family through
+a prolonged period of time, of course, renders the latter likely to
+infection unless unusual care is exercised. Very often where a parent is
+consumptive a child contracts the malady shortly after birth and is
+particularly likely to do so if the mother, who nurses it and cares for it
+most intimately, is the tubercular member of the family. Where the mother
+is tubercular, indeed, the probabilities are that the child has already
+before birth had its vitality lowered through the toxins circulating in
+her blood or through defective nutrition, and in consequence does not
+resist well any diseases.
+
+Undoubtedly a large proportion of our infant mortality is of tubercular
+origin. It is now a well-established fact that much tuberculosis in
+children is attributable to drinking milk from tuberculous cows, yet we
+find individuals so uninformed and dairymen so mercenary that they fight
+all attempts of the commonwealth to test out cattle for tuberculosis so as
+to condemn the infected individuals and thus save our babies. Recent
+investigations made in some of our large pork-packing establishments also
+indicate that hogs, especially such as have been around tubercular
+cattle, are often shot through and through with tuberculosis and that such
+flesh when used as food, if not thoroughly cooked, may become a serious
+menace to our health.
+
+With the wide prevalence of bovine and human tuberculosis it is little
+wonder that nearly every human being becomes more or less infected at some
+period of life. Autopsies on large numbers of individuals in some of our
+great hospitals have shown that as many as ninety-nine per cent. of the
+subjects show tubercular lesions of some kind. While it is true that the
+class of people who would come to autopsy in such public hospitals would
+perhaps be more likely to be tubercular than the average of the community,
+still it can not be denied that a very large degree of infection exists.
+Pearson, from statistics gathered in Europe, has shown that about eighty
+to ninety per cent. of the population have tubercular lesions before the
+age of eighteen. Hamburger found that in Vienna ninety-five per cent. of
+the children of the poor, between twelve and thirteen years of age, were
+infected with tubercular bacilli and he estimates that all would be before
+maturity. According to Doctor Mott, pathologist to the London County
+Asylums, the insane between the ages of fifteen and thirty-five are about
+fifteen times as likely to acquire tuberculosis as the sane are.
+
+Yet the mortality from tuberculosis, great though it be, is obviously not
+in proportion to the enormous degree of infection. The crux of the
+situation is mainly the matter of resistance. From the standpoint of
+heredity, therefore, the question largely resolves itself into one of the
+inheritance or non-inheritance of constitutional resistance. Some are
+predisposed to be non-resistant and hence succumb.
+
+The work of Karl Pearson[5] and other recent researches forcibly indicate
+that hereditary constitutional predisposition is one of the chief factors
+concerned in subjects who develop well defined attacks of the disease. Yet
+we must not forget that there are degrees of susceptibility and that
+therefore a constitutional predisposition which might be of little
+significance under good average conditions of nutrition and sanitation
+might be insufficient under unfavorable conditions.
+
+Before we can make any relatively accurate estimate of the exact degree to
+which the malady is based on inheritance we must have more data. Many
+difficulties beset the path of the investigator. In the first place, when
+one gets back a generation or two he finds that diagnosis was crude and
+uncertain; a given malady may or may not have been tuberculosis. The main
+error however was probably on the side of not recognizing it in mild or
+obscure cases. Then again the questions of virulence of the infection, of
+size and frequency of the dose, etc., are also complicating factors.
+Moreover, in very many cases the infection is a mixed one and hence we are
+dealing with other factors than straight tuberculosis.
+
+=Two Individuals of Tubercular Stocks Should Not Marry.--=However,
+sufficient is now known of the inheritance of susceptibility to the
+disease that we can have little conscience toward the welfare of the race
+if we in any way countenance the marriage of two individuals who come each
+of tubercular strains, and marriage of even a normal person into a badly
+tainted strain, where the one married is tubercular, is extremely
+hazardous looked at from the standpoint of the children likely to be born
+of such a union. The Supreme Court of New York recently held that the
+fraudulent concealment of tuberculosis by a person entering into a
+marriage relation is ground for the annulment of the marriage.
+
+=Special Susceptibility Less of a Factor in Many Diseases.--=With some
+diseases such as leprosy, typhoid fever, smallpox and cholera there seems
+to be less a question of special susceptibility since nearly all persons
+are vulnerable. Yet in cases of typhoid, at least, there are some
+indications that certain families are more likely to take the disease than
+others under similar exposure. We know of no inherited effects of such
+diseases, however. For instance, children of lepers do not inherit leprosy
+and if kept out of leper districts remain normal.
+
+=Deaf-Mutism.--=In certain abnormal states there is danger of confusing
+similar conditions which may have two entirely different sources of
+origin. Deafness, for example, may be strictly inborn as the outcome of a
+germinal variation or it may result from extraneous influences such as
+accidents, infective diseases, neglected tonsils and the like. The former
+is inheritable, the latter not. Bell in 1906 in a special census report to
+the United States government showed that deaf-mutism is markedly
+hereditary, particularly where deaf-mutes intermarry as they are prone to
+do. Fay's extensive studies on _Marriage of the Deaf in America_ also
+demonstrate the hereditary nature of the congenital forms of deafness. Cut
+off as such individuals are from communication with normal people, the
+association of the two sexes in special schools and institutions is of
+course highly conducive to such marriages. The defect seems to behave in
+the manner of a Mendelian recessive. Two deaf-mutes should not have
+children and yet such marriages are occurring every day. Even if two
+persons marry from families which tend to become hard of hearing the
+evidence indicates that their children are likely also to develop this
+partial deafness as they grow older, although it seems safe for a person
+of such tendency to marry into a family without it.
+
+=Gout.--=In such disorders as gout there is little question but that a
+tendency to it runs in families. On the other hand it may also be acquired
+without special susceptibility. There is no evidence, however, that
+because a father has gout the effect of the gout is reflected on his
+germ-cells and the son has gout as a result. Indeed, often a son who
+becomes gouty was born long before the father became gouty. Son and father
+both have gout then, because each has innate germinal tendencies which
+when subjected to certain evocative stimuli become expressed as gout.
+
+=Nervous and Mental Diseases.--=Inasmuch as the question of nervous and
+mental diseases has become one of such overshadowing importance at the
+present day, a discussion of the subject at some length will be presented
+in a separate chapter. I shall merely point out here that the general
+verdict of experts in nervous and mental disorders is to the effect that
+externally induced mental disorders are of rare occurrence except as the
+result of general poisoning or enfeeblement of the system in some way, or
+by traumatic conditions such as a blow on the head, and that there is no
+evidence of the transmission of the effects of such conditions. In most
+cases of insanity, supposedly caused by fright or worry, a close study of
+the family stock will reveal nervous instability of some kind. The
+supposed cause has been merely the precipitating stimulus which has
+brought to expression a dormant weakness of germinal origin. The stress
+and strain of modern life is particularly likely to test out and reveal
+such neurally unstable individuals.
+
+=Other Disorders Which Have Hereditary Aspects.--=Space will not permit
+discussion of various other specific disorders which are known to have
+important hereditary aspects, although none shows any convincing evidence
+of having become hereditary in nature through first affecting the soma.
+Some of these, such as epilepsy and other nervous affections,
+tuberculosis, color-blindness, cataract and various malformations, have
+already been mentioned. Others that may be listed are cancer,
+arterio-sclerosis, obesity and certain forms of rheumatism, and of heart
+and kidney diseases. In practically all of these cases in which heredity
+enters as a factor the condition is one of inheriting a special
+susceptibility and not the disease itself. Which means simply that the
+disorder in question is much more easily called forth in such persons by
+appropriate bacterial or other stimulus, than in the case of the normal
+individual.
+
+=Induced Immunity Not Inherited.--=Lastly, it is well known that various
+animals, including man, after recovery from an attack of any one of
+certain diseases, become more or less immune from further attacks of the
+same disease. Moreover in some instances as in inoculation against typhoid
+or diphtheria, immunity may be artificially induced by means of
+anti-toxins. The question arises as to whether such immunity is
+transmitted to offspring. Experiments have been made (see _Bulletin No.
+30, U. S. Hygienic Laboratory_) to test this and it has been found that
+the condition is not inherited. Young guinea-pigs, for instance, born of
+mothers immunized during pregnancy are immune at birth but they lose their
+immunity in the course of a few weeks. The effect is clearly one of direct
+transference from the blood of the mother. The same temporary immunity can
+be produced in the young, in fact, by merely having them nurse from an
+immunized mother.
+
+=Non-Inheritance of Parental Modifications Has Social, Ethical and
+Educational Significance.--=Like many other biological conclusions these
+relative to the non-inheritance of parental modifications are of extreme
+importance to humanity. It is clear that they have not only physical but
+social, ethical and educational significance. For if the education which
+we give our children of to-day, or the desirable moral conduct which we
+inculcate does not affect the offspring of succeeding generations through
+inheritance, then the actual progress of the race is much slower than is
+commonly supposed, and the advance of modern over ancient times lies more
+in an improvement in extraneous conditions through invention and the
+accumulation and rendering accessible of knowledge, than in an actual
+innate individual superiority. And when we face the issue squarely we have
+to admit that there is no more indication of the inheritance of parentally
+acquired characters as regards customs, knowledge, habits and moral
+traditions than there is of physical features. In fact, if such
+acquirements were inherited then we should soon have a race which would
+naturally, spontaneously as it were, do what its ancestors did with
+effort. Yet we do not find the children in our schools reading, doing sums
+and developing proper social relations without ceaseless prompting and
+urging on the part of the teacher. Indeed I can testify that this
+necessity carries over even into a university. In short, the habits and
+standards of each generation have to be instilled into the succeeding
+generation.
+
+=No Cause for Discouragement.--=At first glance when we realize that
+notwithstanding our individual advancement, that in spite of all our
+painstaking efforts toward self-improvement, we can not add one jot or
+tittle to the native ability of our children, that, aside from possible
+advantageous germinal variations, they will have to start in at
+approximately the same level as we did, and like us will have to struggle,
+or be coaxed, pulled or spurred up to the higher reaches of attainments,
+we are apt to feel discouraged and to look on heredity as the hand of fate
+which irrevocably bars progress. But there is another side to the picture.
+This very fact of heredity which can not be altered at will is the
+conservative factor which maintains the excellence of our standard strains
+of plants and animals, and sustains man himself at his present level of
+accomplishment. While we are denied advancement through the efforts of the
+flesh, we are also largely protected from our misfortunes and follies, as
+witness the non-inheritance of mutilations, of various maladies of
+extrinsic origin, or of personally acquired bad habits.
+
+=Improved Environment Will Help Conserve the Superior Strains When They Do
+Appear.--=If we can not hand on to our descendants a personally enhanced
+blood heritage, we at least can do our share toward building up a social
+heritage of established truth, of efficient institutions and of
+stimulating ideals, through which their dormant capacities may be led to
+expand more surely and more effectively to their uttermost limits. Each
+advance in such social heritage will tend more and more to create an
+atmosphere which will make it sure that the occasional real progressive
+and permanent variations which occur from time to time will find adequate
+expression and preservation in future lines of descendants. It will reduce
+the numbers of our "mute, inglorious Miltons" by more certainly disclosing
+the individual of exceptional talents and insuring for him an opportunity
+of revealing them to the best advantage. Above all, since surrounding
+influences are especially powerful on young and developing organisms, we
+should realize that great care must be exercised in behalf of the young
+child to secure an environment which is saturated with wholesome
+influences. For it is a rule of development that if the environment is
+faulty the organism is impaired.
+
+
+
+
+CHAPTER VI
+
+PRENATAL INFLUENCES
+
+
+=All That a Child Possesses at Birth Not Necessarily Hereditary.--=We come
+now to the more specific discussion of what may happen to offspring of
+mammals, and particularly man, in the interval between fertilization and
+birth; that is, during the intra-maternal period. We have already seen
+that anything affecting the offspring during this period has to be
+reckoned as environmental, our formula reading, Mammal = germ +
+intra-maternal environment + external environment. It is evident, then,
+that all that a child possesses at birth is not necessarily hereditary,
+since the unborn child may be influenced by conditions prevailing in
+either parent.
+
+=The Myth of Maternal Impressions.--=In order to clear the way for more
+urgent matters let us first inquire into the question of the production of
+changes in the unborn child as a result of "maternal impressions." As the
+tale generally goes, structural changes are produced in the unborn child
+corresponding to some mental experience of the mother, usually a vivid
+impression of strong emotion, but when a given individual is pinned down
+to sources, it is usually a case of hearsay.
+
+Stock examples are: The mother sees a mouse with the result that a
+mouse-shaped birthmark occurs on the child; or she sees a crushed hand
+and in consequence bears a child later with some of the bones of the hand
+missing; the mother touches her body when frightened and thus marks the
+unborn child on the corresponding part of the body; or she produces beauty
+in the child by long contemplation of a picture of a beautiful child; and
+so on almost endlessly. The favorite is usually the production of a red
+birthmark or marks on the child's body by strong desire on the part of the
+mother for strawberries, tomatoes, etc.--the fruit must be red since the
+mark is red--or by fright from seeing a fire. As a matter of fact it is
+not uncommon for the capillary blood vessels of the skin of a new-born
+infant to remain dilated in spots instead of contracting as they normally
+should do. The result is more or less of a red or "flame" spot. It is easy
+to see, therefore, why such birthmarks are so frequently referred back by
+the credulous mother to her desire for or fear of some red object.
+
+An analysis of the case of a child shuddering at the sight of peaches is
+of interest in this connection. The child showed the greatest aversion to
+peaches, particularly to the fuzzy covering. The mother's explanation was
+that peaches were unusually plentiful the year the child was born and that
+she had worked hour after hour at peeling and canning peaches shortly
+before his birth until she had become thoroughly sick of them. This
+acquired aversion on her part she believed had been transferred to the
+child. A few questions revealed the fact, however, that the mother,
+herself, had never liked peaches and when asked if they were distasteful
+to any other member of her own family she exclaimed, "Oh, yes, my mother
+would shudder and shake if a peach were brought near her." And there we
+have it. The idiosyncrasy was an inherited one as many similar
+peculiarities are. The mental impression produced in the mother by her own
+experience with peaches had nothing to do with its occurrence in the
+child.
+
+Very frequently also one encounters the mother who is sure she has
+engendered musical ability in her child by constant practise and study of
+music during pregnancy. The child is musical; what better evidence does
+one want! It seems never to occur to such a mother that the child is
+musically inclined because she herself is, as is evinced by her own desire
+in the matter even if she is not a skillful performer.
+
+When we take into account the extreme credulity of many people, the
+unconscious tendency of mankind to give a dramatic interpretation to
+events where causes are not certainly known, the hosts of coincidences
+that occur in life, and the multitude of cases where something should
+happen but nothing does, we are compelled to believe that the whole matter
+of direct specific influence of the mother's mind on the developing fetus
+is a myth. After seeing the conditions which prevail in Mendelism, for
+example, it will take strong faith to believe that a mother with duplex
+brown eyes can "think" or "will" blue eyes on her baby, yet this would be
+a mild procedure compared to some we are asked to accept by believers in
+the transmission of maternal impressions. Most of all, however, when we
+recall the actual relation between the embryo and the mother--a narrow
+umbilical cord is the sole means of communication between the two--the
+physical impossibility of a connection between some particular mental
+happening of the mother and a corresponding specific modification in the
+fetus becomes evident. For there are no nerves in the umbilical cord, the
+only path of communication between mother and fetus being the indirect one
+by way of the blood stream. Even this method of communication is limited
+inasmuch as the mother's blood does not circulate through the blood
+vessels of the fetus. Gaseous and dissolved substances are merely
+interchanged through the thin walls of the capillary blood vessels in the
+placenta.
+
+=Injurious Prenatal Influences.--=However, the denial that a particular
+mental impression of the mother is associated with a particular structural
+defect in a child does not carry with it the implication that prenatal
+influences of all kinds are negligible factors. On the contrary any
+deleterious effect which can reach the fetus through absorption from the
+blood of the mother may be of grave consequence. There is not the least
+doubt that malnutrition or serious ill-health on the part of the mother
+often has a prejudicial effect on the unborn offspring. Severe shock or
+grief, worry, nervous exhaustion, the influence of certain diseases,
+poisons in the blood or tissues of the parent, such as lead, mercury,
+phosphorus, alcohol and the like, may all act detrimentally, but they
+operate either by rendering nutrition defective, by direct poisoning, or
+by generating toxins in the blood of the parent which then poison the
+fetus. Among the latter may be mentioned the toxic products of
+tuberculosis and certain other bacterial diseases. Such factors operating
+on the unborn young or even on the germ-cells may cause malformations,
+arrests of development, instabilities of the nervous system, and general
+physical or mental weakness. The effects are general, however, and not
+specific.
+
+To distinguish certain of these prenatal effects, particularly those of
+certain diseases or poisons, from true hereditary influences they are
+frequently spoken of as cases of _transmission_ rather than inheritance
+from parents. Some writers use the technical term _blastophthoria_, or
+false-heredity, extending the meaning so as to include also any damage
+that might be inflicted on the germ-cells.
+
+=Lead Poisoning.--=By way of illustration of how certain cumulative
+poisons may act we may examine a tabulation of eighty-one cases of lead
+poisoning as reported by Constantin Paul (Fig. 29, p. 164).
+
+The table requires little comment. The disastrous effects of such
+poisoning are apparent in every class of cases. The sixth class where the
+husband alone was exposed to lead shows that the poison can operate
+directly through the germ-cell. Other observers note that in the children
+of workers in lead, there is a distressing frequency of feeble-mindedness
+and epilepsy.
+
+That lead poisoning operating through the germ-cells of the father can
+affect the development of the young harmfully is well shown in Fig. 30, p.
+165, which is a photograph of two young rabbits from the same litter The
+white young one is from a normal albino mother mated to an albino father
+which had received lead treatment. The pigmented young one is from the
+same albino mother by a normal pigmented father. Although the white
+father was considerably larger than the pigmented father, nevertheless the
+young of the former, because of the harmful effects of the lead, is
+distinctly smaller and less lively. A number of litters, each from the
+same mother but in part from a lead-poisoned father and in part from a
+normal father, have been secured. All show more or less the same results.
+The experiments are still in progress in the department of experimental
+breeding at the University of Wisconsin.
+
+  --------------------------------------------------------------------
+                       |Number of cases.
+                       |     +----------------------------------------
+                       |     |Number of pregnancies.
+                       |     |      +---------------------------------
+                       |     |      |Abortions, premature labor, and
+                       |     |      |  stillbirths.
+                       |     |      |     +---------------------------
+                       |     |      |     |Infants born living.
+                       |     |      |     |      +--------------------
+                       |     |      |     |      |Remarks.
+  ---------------------|-----|------|-----|------|--------------------
+  1. Mother showing    |     |      |     |      |One infant died
+  symptoms of plubism  |  4  |  15  |  13 |   2  | within 24 hours.
+                       |     |      |     |      |
+  2. Mother working in |     |      |     |      |
+  type foundry, all    |     |      |     |      |
+  of whose previous    |     |      |     |      |
+  pregnancies had      |     |      |     |      |Four of these died
+  been normal          |  5  |  36  |  29 |   7  | in first year.
+                       |     |      |     |      |
+  3. Mother who during |     |      |     |      |
+  period of work in    |     |      |     |      |After ceasing to
+  type foundry had     |     |      |     |      | work had
+  five pregnancies     |  1  |   5  |   5 |   0  | healthy child.
+                       |     |      |     |      |
+  4. Mother working    |     |      |     |      |When away from
+  intermittently in    |     |      |     |      | work for some
+  type foundry;        |     |      |     |      | period of time
+  while working        |     |      |     |      | gave birth to
+  there                |  3  |   3  |   3 |   0  | healthy children.
+                       |     |      |     |      |
+  5. Mother in whom    |     |      |     |      |
+  blue line on gum     |     |      |     |      |
+  the only sign of     |     |      |     |      |
+  lead poisoning       |  6  |  29  |  21 |   8  |
+                       |     |      |     |      |Of these, eight died
+  6. Husband alone     |     |      |     |      | in first year,
+  exposed to lead      |  ?  |  32  |  12 |  20  | four in second,
+                       |     |      |     |      | five in third.
+  --------------------------------------------------------------------
+
+FIG. 29
+
+Tabulation of eighty-one cases of lead poisoning recorded by Constantin
+Paul (from Adami).
+
+
+[Illustration: Fig. 30
+
+Photograph of young rabbits from the same litter, the smaller one stunted
+by lead-poisoning of its father (Courtesy of Professor L. J. Cole).]
+
+
+=The Expectant Mother Should Have Rest.--=The mere matter of rest on the
+part of the pregnant mother is, judging from the work of Pinard, a
+Frenchman, and his pupils, an important one. In a number of detailed
+investigations they have shown that rest on the part of the working mother
+during the last three months before the child is born results in the
+production of markedly larger and more robust children than those born of
+mothers equally healthy but who have not had such rest. Moreover the
+danger of premature birth is considerably lessened.
+
+=Too Short Intervals Between Children.--=Too short an interval between
+childbirths would also seem to be an infringement on the rights of the
+child as well as of the mother. Thus Doctor R. J. Ewart ("The Influence of
+Parental Age on Offspring," _Eugenic Review_, October, 1911) finds that
+children born at intervals of less than two years after the birth of the
+previous child still show at the age of six a notable deficiency in
+height, weight and intelligence, when compared with the children born
+after a longer interval, or even with first-born children.
+
+=Our Duty to Safeguard Motherhood.--=Doubtless the unventilated factory
+and tenement also do their share, even though we can give no exact
+quantitative measure of it. Obviously, it becomes a civic duty to protect
+as much as possible all members of our social system from such injurious
+factors as have just been discussed. It is particularly necessary to
+safeguard mothers before confinement, especially working mothers.
+
+=Expectant Mothers Neglected.--=According to the claims of life insurance
+men, expectant mothers are the most neglected members of our population.
+Doctor Van Ingen, of New York City, estimates that ninety per cent. of
+women in this country are wholly without prenatal care. Yet every
+prospective mother should be taught the probable meaning of such symptoms
+as headache, hemorrhages, swelling of the feet and disturbed vision. She
+should realize the importance of submitting a sample of urine for analysis
+at least once a month before childbirth and twice a month for a while
+thereafter. She should be specially informed regarding work, exercise,
+diet and dress. A recent government bulletin written by Mrs. Max West
+which may be had free by writing to the Children's Bureau, Department of
+Labor, Washington, D. C., gives much useful information on this subject.
+
+
+ALCOHOLISM
+
+=Unreliability of Much of the Data.--=One of the most important poisons
+that plays a prominent part among ante-natal influences is alcohol. But
+when it comes to a study of the problem of alcoholism from the standpoint
+of heredity and parental influences we meet with many difficulties,
+prominent among which are the inaccuracy and unreliability of many of the
+statistics brought forward in this connection. Many of the results are
+vitiated by the prejudices of propagandists who propose to make a case
+either for or against alcohol as a beverage whether or not the facts
+justify their conclusions. When one tries to view the matter with an open
+mind he finds that there is a deplorable lack of statistics which are not
+susceptible to more than one interpretation. However, using as much as
+possible what seems to be unbiased data, the evidence is almost wholly
+against alcohol as a beverage, at least to any immoderate extent.
+
+=Alcohol a Germinal or Fetal Poison.--=The bad effects as far as offspring
+are concerned reveal themselves in the main under the category of "false
+heredity," i. e., germinal or fetal poisonings rather than of heritable
+changes induced in the germ-cells. Most investigators feel that there are
+too many criminal, imbecile, insane and unhealthy persons among the
+offspring of drunkards to dismiss the matter as a coincidence. In an
+investigation of Imbault, for example, we find recorded of one hundred
+tuberculous children that while forty-one were of tuberculous parentage,
+thirty-six per cent, were the offspring of inebriates. Furthermore Imbault
+cites the observations of Arrivé on 1,506 cases of juvenile meningitis to
+the effect that this malady is twice as frequent in the children of
+alcoholic as in those of tuberculous parentage. It has been proved by
+Nicloux (_L'Obstetrique_, Vol. 99, 1900) that in dogs and guinea-pigs
+alcohol passes through the placenta and may be detected in fetal tissues;
+hence it is in position to influence the fetus. He found that in a very
+short time the amount of alcohol in the blood of the fetus about
+paralleled that in the blood of the mother.
+
+=Progressive Increase in Death-Rate of Offspring of Inebriate Women.--=In
+an investigation on the effects of parental alcoholism on the offspring,
+Sullivan (_Journal of Mental Science_, Vol. 45, 1899) gives some
+important figures. To avoid other complications he chose female drunkards
+in whom no other degenerative features were evident. He found that among
+these the percentage of abortions, still-births and deaths of infants
+before their third year was 55.8 per cent. as against 23.9 per cent. in
+sober mothers. In answer to the objection that this high percentage may be
+due merely to neglect, and not to impairment of the fetus by alcoholism,
+he points out the fact based on the history of the successive births, that
+there was a progressive increase in the death-rate of offspring in
+proportion to the length of time the mother had been an inebriate, thus:
+
+  -------------------------------------------------------------
+                   |No. of|Per cent.|Per cent. dying|  Total
+                   |cases |born dead|   before 3    |percentage
+  -----------------|------|---------|---------------|----------
+  First births     |  80  |   6.2   |     27.5      |   33.7
+  Second births    |  80  |  11.2   |     40.8      |   50.0
+  Third births     |  80  |   7.6   |     45.0      |   52.6
+  Fourth and fifth | 111  |  10.8   |     54.9      |   65.7
+  Sixth to tenth   |  93  |  17.2   |     54.8      |   72.0
+  -------------------------------------------------------------
+
+=Views of a Psychiatrist on Alcohol.--=Forel, who for years was the
+psychiatrist at the head of a large insane asylum at Zurich, Switzerland,
+has this to say about the effects of narcotic poisons and alcohol in
+particular:
+
+    "The offspring tainted with alcoholic blastophthoria suffer various
+    bodily and physical anomalies, among which are dwarfism, rickets, a
+    predisposition to tuberculosis and epilepsy, moral idiocy, and idiocy
+    in general, a predisposition to crime and mental diseases, sexual
+    perversions, loss of suckling in women, and many other misfortunes."
+
+In another passage he[6] remarks as follows:
+
+    "But what is of much greater importance is the fact that acute and
+    chronic alcoholic intoxication deteriorates the germinal protoplasm of
+    the procreators.... The recent researches of Bezzola seem to prove
+    that the old belief in the bad quality of children conceived during
+    drunkenness is not without foundation. Relying on the Swiss census of
+    1900, in which there figure nine thousand idiots, and after careful
+    examination of the bulletins concerning them, this author has proved
+    that there are two acute annual maximum periods for the conception of
+    idiots (calculated from nine months before birth); the periods of
+    carnival and vintage, when the people drink most. In the wine-growing
+    districts the maximum conception of idiots is enormous, while it is
+    almost nil at other periods. Moreover, these two maximum periods come
+    at the time of year when conception is at a minimum among the rest of
+    the population, the maximum of normal conceptions occurring at the
+    beginning of summer."
+
+Another interpretation of Bezzola's results has been suggested to the
+effect that the license of these periods enables the defective members of
+the community, such as the feeble-minded, an opportunity of mating more
+readily and that consequently the result is direct inheritance of idiocy
+and allied defects instead of idiocy produced through alcoholic poisoning
+of the parental germ-cell.
+
+=Other Views.--=There are indeed many competent investigators who believe
+that alcoholism in parents has little or no part in the direct production
+of mental defects in children. For instance, Tredgold quotes Doctor
+Ireland's observations that although at New Year, when the fishermen
+return, the whole population of certain villages in Scotland gets drunk,
+there is no noticeable excess of defectives born nine months later, and
+remarks further that, "I have histories of idiots conceived under such
+circumstances, but so I have of normal children, and my opinion is, that
+while this may be a cause in some cases, the number of instances in this
+country at any rate is exceedingly small." Again, Goddard, one of our best
+known American students of feeble-mindedness, who has made careful study
+of this point under especially favorable conditions, feels that his data
+do not prove that alcoholism of either the father or the mother causes
+feeble-mindedness in the child. He concludes, "Everything seems to
+indicate that alcoholism itself is only a symptom; that it for the most
+part occurs in families where there is some form of neurotic taint,
+especially feeble-mindedness." Goddard, however, in common with many other
+observers, notes that miscarriages and deaths in infancy are far higher
+among inebriates than among abstainers.
+
+Doctor Mjöen cites an interesting parallel between the increase of
+feeble-mindedness in Norway and a period from 1816 to 1835, when every one
+was permitted to distil brandy. In some districts many of the farmers
+distilled brandy from corn and potatoes, and in such regions during this
+period feeble-mindedness increased nearly one hundred per cent. Later the
+home distillation of brandy was stopped. According to Doctor Mjöen, "The
+enormous increase in idiots came and went with the brandy." He is
+inclined to believe, however, that the alcohol operated injuriously mainly
+on stocks already defective.
+
+=The Affinity of Alcohol for Germinal Tissue.--=Nicloux and Renault have
+shown that alcohol has a decided affinity for the reproductive glands. In
+individuals who have recently taken alcohol the proportion of alcohol in
+the gonads is soon almost equal to the amount found in the blood. Thus in
+experiments on mammals it was found that the proportion of alcohol in the
+ovary to that in the blood was as three to five, and in the testis as two
+to three. This would afford abundant opportunity for alcohol to act
+directly on the spermatozoon or the ovum.
+
+A number of different investigators concur in finding that the germ-glands
+of the male human inebriate in many cases show more or less atrophy and
+other degenerative changes. In guinea-pigs which have been repeatedly
+intoxicated with alcohol, Stockard found that while he could detect no
+visible abnormality in the gonad, nevertheless their defective and
+weakened progeny showed that the germ-cells had been affected.
+
+=Innate Degeneracy Versus the Effects of Alcohol.--=Many observations on
+human beings have been brought forward which at first sight seem to
+indicate that noticeable defects, particularly mental and nervous, occur
+with appalling frequency in children resulting from conception during
+intoxication, although, unfortunately, the evidence is rarely clear as to
+whether the defects are really due to the effects of the alcohol or to the
+fact that the parent or parents were degenerate to begin with.
+
+A very interesting human case cited by Forel on the authority of
+Schweighofer is that of a normal woman who had three sound children when
+married to a normal man. After the death of this husband she married an
+inebriate by whom she had three other children. One of these suffered from
+infantilism, one turned out to be a drunkard, and the third became a
+social degenerate and drunkard. Moreover the first two contracted
+tuberculosis, although hitherto the family stock had been free from this
+malady. Ultimately the woman married again and by this third husband, who
+was normal, she again had sound children. Similar cases might be cited,
+as, for example, a record of eighty-three epileptics, of whom sixty had
+drunken parents, but it can be urged against all of them, of course, that
+the defective offspring were due to an innate degeneracy of the drunken
+parent which made him a drunkard rather than to the effects of the alcohol
+he took. While one is skeptical as to the validity of this objection in
+all of the many cases which occur with such monotonous frequency in man,
+there is no way of escaping such an interpretation with the evidence at
+hand. It must be admitted, moreover, that there are many families with one
+or both parents alcoholic in which the children are not mentally
+defective.
+
+=Experimental Alcoholism in Lower Animals.--=Many of the objections that
+exist in the case of man, however, do not apply in that of lower animals.
+If normal animals are experimentally alcoholized and are shown to produce
+defective offspring under such conditions, then in their cases at least,
+the disorders in the offspring must be due to the effects of alcohol and
+not to an innately degenerate condition of the parent. Disorders similar
+to some of those seen in the children of alcoholics do actually result in
+alcoholized animals of one kind or another.
+
+Against the earlier experiments on animals it has been urged that too few
+individuals were used to give conclusive results, but this objection can
+not be brought against the recent experiments of Stockard. While he has
+published accounts of his work in various scientific periodicals lately,
+the reader will find a full statement of his own experiments, together
+with a review of the whole subject of experimental alcoholism in animals
+and the effects on progeny in _The American Naturalist_, Vol. XLVII,
+November, 1913, together with a useful bibliography.
+
+Before taking up Stockard's results we may select a few of the more
+significant experiments made earlier by other investigators.
+
+Laitinen alcoholized rabbits and guinea-pigs. He found that the treated
+individuals had more still-born young than the control, and also that
+growth of the living young was retarded. His alcoholized rabbits and
+guinea-pigs produced more young than did the normal individuals used as a
+control. Laitinen's studies on man, together with three other studies of
+the Eugenics Laboratory in London, show that in man also more children are
+born to alcoholics than to normal parents. Goddard's investigations in
+America corroborate this fact.
+
+Ceni found that only 43 per cent. of the eggs from alcoholized fowls
+developed normally, as against 77 per cent. of normal development in the
+controls. Moreover the eggs of alcoholic fowls were shown to be less
+resistant to adverse conditions than normal eggs from the fact that
+fluctuations of temperature at the beginning of incubation kept all the
+alcoholic eggs from developing perfectly, while 27 per cent. of the
+control eggs developed normally under the same adverse circumstances.
+
+Hodge made a pair of dogs alcoholic. Of 23 pups obtained from the pair, 8
+were deformed and 9 were dead; 4 alone were viable. From a control pair of
+dogs 45 pups were obtained, of which 4 were deformed, none were born dead,
+and 41 were viable.
+
+=Stockard's Experiments on Guinea-Pigs.--=Stockard's experiments
+demonstrate that the offspring of mammals may be injured or modified in
+their development by treating either parent repeatedly with alcohol. The
+guinea-pigs used in the experiment were all first tested by normal matings
+and found to yield normal offspring. The alcohol was given to them by
+inhalation. It was found to be readily taken into the animals' blood and
+to produce intoxication. While guinea-pigs alcoholized in this way as
+often as six times a week for two and one-half years would maintain their
+own bodily vigor and health apparently, the deleterious effects on their
+progeny were marked. The defects were general rather than specific,
+although the central nervous system and special sense organs were
+apparently affected most.
+
+Out of 119 total young produced by the alcoholic animals, only 52, or less
+than 44 per cent., survived, whereas out of 64 young produced from normal
+parents used as a control for the experiment, 56, or over 87 per cent.,
+survived. In some cases alcoholic males were mated with normal females, in
+other, alcoholic females with normal males. In still other instances both
+parents were alcoholic.
+
+The results are summarized in the accompanying table (Fig. 31), taken from
+Stockard's paper:
+
+  CONDITION OF THE OFFSPRING FROM GUINEA-PIGS TREATED WITH ALCOHOL
+
+  -----------------------------------------------------------------
+                      |Number of Matings
+                      |     +--------------------------------------
+                      |     |Negative Result or Early Abortion
+                      |     |    +---------------------------------
+                      |     |    |Stillborn Litters
+                      |     |    |    +----------------------------
+                      |     |    |    |Number Stillborn Young
+                      |     |    |    |      +---------------------
+                      |     |    |    |      |Living Litters
+                      |     |    |    |      |    +----------------
+                      |     |    |    |      |    |Young Dying Soon
+                      |     |    |    |      |    |  After Birth
+                      |     |    |    |      |    |      +---------
+  Condition of        |     |    |    |      |    |      |Surviving
+   the Animals        |     |    |    |      |    |      |  Young
+  --------------------|-----|----|----|------|----|------|---------
+  Alcoholic [male] by |     |    |    |      |    |      |
+    normal [female]   |  59 | 25 |  8 |  15  | 26 |  21  |  33
+  Normal [male] by    |     |    |    |      |    |      |
+    alcoholic [female]|  15 |  3 |  3 |   9  |  9 |   9  |  10
+  Alcoholic [male] by |     |    |    |      |    |      |
+    alcoholic [female]|  29 | 15 |  3 |   6  | 11 |   7  |   9
+  SUMMARY             | 103 | 43 | 14 |  30  | 46 |  37  |  52
+  Normal [male] by    |     |    |    |      |    |      |
+    normal [female]   |  35 |  2 |  1 |   4  | 32 |   4  |  56
+  2d generation       |     |    |    |      |    |      |
+    by normal         |   3 |  0 |  0 |   0  |  3 |   0  |   4
+  2d generation       |     |    |    |      |    |      |
+    by alcoholic      |   3 |  0 |  2 |   5  |  1 |   0  |   2
+                      |     |    |    |1 def.|    |      |
+  2d generation       |     |    |    |      |    |      |
+    by 2d generation  |  19 |  7 |  0 |   0  | 12 |   6  |  13
+                      |     |    |    |      |    |1 def.|
+  Female treated      |     |    |    |      |    |      |
+    during pregnancy  |   4 |  0 |  0 |   0  |  4 |   1  |   7
+  -----------------------------------------------------------------
+
+FIG. 31
+
+Table showing condition of the offspring from guinea-pigs treated with
+alcohol (after Stockard).
+
+Lines four and five give a comparison between the 103 total matings of all
+treated individuals and 35 normal matings. In the first case almost 42 per
+cent. of the matings gave negative results or early abortions, whereas in
+the normal control matings, failure to yield a full-term litter occurred
+in only two cases. The 103 matings of alcoholic animals gave only 46
+living litters, or about 45 per cent. On the other hand the 35 control
+matings produced 32 living litters, or 91-1/2 per cent. It will be
+observed also that from such of the 103 matings of alcoholics as produced
+young there were 30 still-born, 37 which died soon after birth, and only
+52 surviving young, whereas from the 35 matings of normal individuals
+there were only 4 still-born young, 4 which died soon after birth, and 56
+surviving young.
+
+The bottom line of the table, although, as Stockard points out, containing
+too few cases to prove wholly convincing, indicates that alcoholizing
+erstwhile normal females during pregnancy was not particularly harmful to
+the embryos _in utero_.
+
+Some of the most interesting results were obtained when offspring termed
+second generation animals, derived from alcoholic parents though not
+themselves treated with alcohol, were mated in various ways. When such
+individuals were mated with normal individuals, although the litters were
+small, the results were normal, the normal mate having seemingly
+counteracted any defects which might have lurked in the second generation
+animal. On the other hand, out of three matings of second generation
+animals with alcoholic individuals, two produced still-born young, of
+which one was markedly deformed, while the third yielded two living young.
+
+However, the most striking results were obtained when two second
+generation individuals, the offspring of alcoholic parents, were bred
+together. Although themselves untreated, these individuals, of which 19
+matings were made, produced as many or more defective young than did their
+alcoholic parents. Seven of the matings were unfruitful. The remaining 12
+matings gave living litters consisting of 19 individuals in all. Six of
+these showed various nerve disorders (spasms, epileptic-like seizures,
+etc.) soon after birth; one was eyeless and otherwise deformed.
+
+=Stockard's Interpretation.--=Stockard's interpretation of his experiments
+is as follows: "Mammals treated with injurious substances, such as
+alcohol, ether, lead, etc., suffer from the treatments by having the
+tissues of their bodies injured. When the reproductive glands and
+germ-cells become injured in this way they give rise to offspring showing
+weak and degenerative conditions of a general nature, and every cell of
+these offspring having been derived from the injured egg or sperm-cell are
+necessarily similarly injured and can only give rise to other injured
+cells and thus the next generation of offspring are equally weak and
+injured and so on. The only hope for such a line of individuals is that it
+can be crossed by normal stock, in which case the vigor of the normal
+germ-cell in the combination may counteract, or at any rate reduce, the
+extent of injury in the body cells of the resulting animal."
+
+He also believes that various deformities and developmental arrests such
+as harelip and cleft-palate may similarly be cases of transmission rather
+than true inheritance, due to the weakening of the germ-cells in some way,
+or to some lack of full vigor in the uterine environment.
+
+=Further Remarks on the Situation in Man.--=Returning now to the question
+of alcoholism in man, it seems in view of the strong circumstantial
+evidence in the case of man himself, together with the result of
+experiments on animals, that little doubt remains that excessive
+alcoholism might result in the production of defective offspring. On the
+other hand an antecedent degeneracy or neural instability undoubtedly
+plays an important part in many cases, in the original production of
+drunkards, and when such occurs, it, as well as the direct effects of
+alcoholic poisoning, must be reckoned with in the effects on progeny.
+Studies carried on by Pearson, Elderton and Barrington of the Eugenic
+Laboratory in London lead these investigators to the conclusion that
+extreme alcoholism is a _result_ not a _cause_ of degeneracy. That is, the
+degeneracy is due to the defective stock, not to alcohol. They cite in
+evidence their records of four thousand school children of alcoholic and
+of sober parents, which fail to show any unfavorable effect of alcohol on
+offspring. Some of their critics, however, maintain that they did not
+choose subjects who were sufficiently alcoholic to give the injurious
+results that might legitimately be expected among the offspring of
+excessive drinkers or habitual drunkards.
+
+Where children show a hereditary inclination toward drink, unquestionably
+one of the strongest factors is the inheritance of the same disposition,
+the same unstable nervous constitution and its accompanying lack of
+self-control which led the parent to drink, rather than the inheritance of
+the effects of the drink on the parent. For in many cases a parent may not
+become a drunkard until after the children who also become drunkards are
+born. That the tendency to drink immoderately is frequently due to a
+strain of feeble-mindedness or epilepsy becomes more evident every day.
+In many of the so-called "periodical" drunkards, the accompanying features
+of their periodic attacks of drink-craving, such as clouding of memory,
+restlessness and depression, are those commonly associated with ordinary
+epileptic attacks.
+
+=Probably Over Fifty Per Cent. of Inebriety in Man Due to Defective
+Nervous Constitution.--=Branthwaite, an English authority on drunkenness,
+finds that about sixty-three per cent. of the inebriates who come to his
+notice are mentally defective. In alcoholic insanities heredity is a
+potent factor. It is coming to be realized more and more that pronounced
+alcoholism is due in a large percentage of cases, perhaps over half, to a
+defective nervous make-up. While it is true that many drunkards would not
+develop without free access to alcohol, on the other hand many would never
+develop without a bad heredity back of them, which gives them a peculiar
+nervous constitution that renders alcohol an undue stimulus. In a recent
+report of the New York State Hospital Commission it is stated that in
+fifty-four per cent. of the cases of alcoholic insanity, a family history
+of insanity, epilepsy or nervous disease exists. Thus in the presence of
+alcohol most of these unfortunates are helpless pawns of a hereditary
+weakness.
+
+So when the question of alcoholism is viewed from all angles, the children
+of the human drunkard would seem to run a double menace of misfortune,
+since they may be subject both to the direct poisoning effects of alcohol
+and the results of an inheritable degeneracy.
+
+=Factors to Be Reckoned With in the Study of Alcoholism.--=In any
+thoroughgoing study of alcoholism in man many factors will have to be
+reckoned with. First of all there is the question of inherent lack of
+control. This is probably the principal thing inherited where heredity
+truly enters as a factor. That example and social environment are
+important factors in addition to or in place of heredity is clear, too,
+when we observe that often it is the boys only who take after a drunken
+father, for there is no evidence that the inherited tendency when it
+really exists is at all sex-linked. Again, in certain occupations carried
+on under unwholesome influences relief is frequently sought in alcoholic
+stimulants, and such custom may easily crystallize into habit.
+Furthermore, the accustoming young children to doses of alcohol, or the
+unborn young to alcohol through the body of a drunken mother, may be
+strongly contributory toward establishing inebriety in certain cases. As
+we have seen from an abundance of experimental data on animals, moreover,
+the nurture effects on germ-cells may result in the production of weakened
+offspring. Such offspring in the case of man are probably less able to
+withstand temptations of all kinds and hence readily succumb to the
+habit-forming effects of alcohol if once its use is begun. Lastly, it must
+not be forgotten that alcoholism in the father usually means poverty and
+the subsequent accompaniment of malnutrition and neglect of the children,
+and this in itself may not only account for poor development of the
+latter, but may also be strongly contributory toward establishing the
+habit of alcoholism in them.
+
+An inherent bias plus most of the other conditions just enumerated is the
+not unusual lot of the offspring of drunkards.
+
+=Venereal Diseases.--=There is yet another very considerable class of
+maritally unfit who in any conscientious discussion of unfitness for
+marriage or of racial improvement must be considered. I refer to those who
+are afflicted with the diseases which are inseparably associated with the
+so-called "social evil." To _gonorrhea_, one of the most prevalent of
+these diseases, more than one-fourth of our total one hundred and ten
+thousand blind in the United States are said to owe their affliction.
+Milder types of eye disease may also result from such infections. As much
+as eighty per cent., or some say practically all blindness in children
+born blind is caused by it, the infection occurring at the time of birth
+or within a few days thereafter. The terrible consequences of this disease
+to the innocent wife would alone make its discussion imperative.
+
+=The Seriousness of the Situation.--=Unfortunately the insidious nature of
+gonorrheal infections is unknown to most persons. A cure is apparently
+effected, yet as a matter of fact the germs may live for years and, if in
+the male, later be transmitted to the wife, subjecting her to a future of
+invalidism and misery. Reliable statistics from various medical
+authorities reveal the appalling fact that seventy-five per cent. or more
+of the surgical operations for inflammatory pelvic disorders peculiar to
+women, such as pus tubes and peritonitis, are attributable to this
+disease, as is also the involuntary sterility of forty-five per cent. of
+childless women. Unwelcome as the fact is there is an abundance of
+evidence to show that a large percentage of men in particular have at
+some period of their life been infected with venereal disease. Of our
+fourteen million males in the United States under the age of thirty we
+find estimates by some specialists in venereal diseases to the effect that
+five million of them, that is, one out of three, suffer from some one of
+the social diseases or their consequences. Doctor Hugh Cabot, one of the
+chief surgeons of the Massachusetts General Hospital at Boston, a member
+of the faculty of the Harvard Medical School and president of the American
+Association of Genito-Urinary Surgeons, has this to say about the
+situation: "We have of late years heard much about the frequency and
+serious consequences of tuberculosis; it has been dubbed the 'white
+plague,' and so active has been the campaign that a wide-spread
+understanding of this serious disease has resulted. It may safely be
+averred that in the urban population at least there are two, and perhaps
+three, individuals with syphilis to every one with tuberculosis. The
+frequency of gonococcus infection is much higher." He believes that over
+half the male population acquire a gonococcus infection at some period of
+their career. While as a layman, one can not but feel that a specialist's
+estimate may run unduly high because of the fact that he is encountering
+an inordinate proportion of such maladies every day, still such
+specialists are in position to get at the truth as no other person can and
+their calculations are probably not grossly in error. In any event any one
+who has progressed in worldly knowledge beyond the naïveté of a child must
+recognize the appalling prevalence of these maladies.
+
+=Infantile Blindness.--=So serious has the matter of infantile blindness
+become that some state boards of health and some city health departments
+supply all physicians and midwives with specially prepared packages
+containing cotton and nitrate of silver solution for preventive or
+curative treatment of the eyes of all new-born children. At the time of
+the first bath each eye is carefully washed with a separate pledget of
+cotton saturated with boric acid solution. Each then receives a drop of
+the silver solution, which is made just strong enough to kill any
+gonococci that might be present without itself inflaming the eye. Water
+used in bathing the baby's body of course is not allowed to come in
+contact with its eyes. Such treatment should be given every child no
+matter how unsuspicious the circumstances may be. German authorities who
+have been following this method now for some years assure us that
+nineteen-twentieths of the blindness of infancy can thus be prevented.
+
+=Syphilis.--=As to _syphilis_, another and even more terrible of these
+diseases, we have before us the absurd fact that while thousands upon
+thousands of dollars are being spent to establish a rigid inspection and
+preventive measures against the spread of a very similar disease in the
+horse, this malady in man is allowed to pass unchallenged and we are
+confronted by the gruesome certainty that there are hundreds of these
+diseased persons about us to-day who, on their mere affirmation that they
+are unmarried and of age, will be given the right to marry and thus
+produce families of infected children irrevocably doomed to early death or
+to lifelong misery.
+
+While syphilis is most commonly spread through relations between the
+sexes, it may be acquired in various other ways, as for example, through a
+cut in shaving with the same razor an infected individual has used. It is
+commonly transmitted from parent to child. Practically every prostitute is
+a center of dissemination. Katherine Bement Davis has shown in her studies
+made at the New York State Reformatory for Women that while ordinary
+clinical tests show that apparently only twenty-one per cent. of these
+women are infected with venereal disease, more careful laboratory tests
+showed at least ninety per cent. to be infected.
+
+Syphilis is caused by _Treponema pallidum_, a small unicellular animal
+parasite. Given access to the blood by any means whatever, possibly even
+through an abrasion in the lip by means of a kiss, it multiplies rapidly
+and any part or organ of the body may be attacked. Usually a small sore
+occurs at the point of entrance to the body, but often it heals up readily
+with little indication of the seriousness of the infection.
+
+The development of the malady is insidious and long continued. As a matter
+of clinical convenience physicians divide its progress into successive
+stages although in reality the transitions are frequently variable and ill
+marked. The symptoms that arise within the first few months or even years
+are readily controlled by appropriate treatment, but to insure a cure
+prolonged and most thoroughgoing treatment is imperative. The symptoms
+disappear so completely after a short period of treatment that it is very
+difficult to persuade the average patient that he is not yet cured. Two
+years at least are none too short a period of treatment, yet the majority
+of patients, fully convinced that they are merely being exploited by the
+physician as a source of revenue, drift away at the end of a few months.
+As a matter of fact, however, the germs usually persist long after the
+obvious symptoms of the disease have disappeared, and in consequence many
+of the most serious results of syphilis may not manifest themselves for a
+period of perhaps ten, twenty or thirty years.
+
+=Some of the Effects.--=It is now known that _paresis_, also termed
+general paralysis or softening of the brain, is probably invariably due to
+syphilis. The work of Flexner and Noguchi on _paresis_ and _tabes
+dorsalis_ show that always in such afflictions the tissues of the central
+nervous system have been invaded by the parasite. The original infection,
+however, may have occurred so long before as to have been almost forgotten
+by the patient. Thus many an apparently robust man is stricken down in the
+prime of life. Earlier and prolonged treatment would in all probability
+have eradicated the germs and thus prevented the mental breakdown, which
+can not be cured by any known treatment. Postmortem examination always
+shows that the _Treponema_ has wrought wide-spread damage in the brain.
+The frequency of paresis may be realized when one learns that in some
+regions it is responsible for about one-fifth of all cases of insanity
+sent to hospitals for the insane. It ranks next to the highest as a cause
+of insanity. Statistics show that in the state of New York more deaths
+result annually from paresis than from smallpox, tetanus, malaria,
+dysentery and rabies all combined.
+
+In some cases the disease attacks the membranes of the brain and the small
+blood vessels giving rise to a still different type of mental disorder.
+Practically all patients with _locomotor ataxia_ owe their condition to an
+antecedent syphilis. Moreover it is one of the important causes of
+_arterio-sclerosis_, or hardening of the blood vessels, and is also a
+prominent factor in certain forms of heart-disease, as well as by no means
+an unimportant cause of blindness in children.
+
+As to specific cases of the effects of this disease on descendants the
+literature of the subject is crowded full. While it is needless to conduct
+the reader through a chamber of horrors by reviewing clinical cases, it is
+desirable to point out in a general way some of the effects. Doctor George
+H. Kirby, director of Clinical Psychiatry, Manhattan State Hospital, says:
+
+    "We find that when either the father or the mother suffers from
+    paresis that many other members of the family may be infected with
+    syphilis, and furthermore, we find that a large number of children in
+    these families are feeble-minded, nervous, or in other ways abnormal.
+    Doctor Plant examined a group of 100 children, the offspring of cases
+    of paresis, and found that 45 per cent. were plainly damaged mentally
+    or physically, or in both fields; the blood test showed that one-third
+    of these 100 children had the syphilitic poison in their systems.
+
+    "Another investigator found in a group of 139 children, the
+    descendants of parents who had syphilitic nervous disease, that over
+    25 per cent. were definitely feeble-minded or affected with some
+    serious nervous disorders.
+
+    "Other studies indicate that there exists a close relation between
+    syphilis and many of the hitherto unexplained cases of
+    feeble-mindedness, including idiocy, imbecility, infantile paralysis,
+    and some forms of epilepsy. While the question is not yet settled, it
+    appears that syphilis is the real cause of many of these cases of
+    mental defect in children."
+
+Still other investigators give details of physical afflictions and
+distortions, of suppressed development, of inordinate percentages of
+stillbirths--perhaps the most merciful lot for the little victims--but
+sufficient has been said to indicate the full horror of the situation.
+
+Goddard,[7] although not minimizing the terrible nature of the disease,
+finds little evidence in his studies that syphilis in parents is a
+specific cause of feeble-mindedness.
+
+=A Blood Test.--=Fortunately a delicate blood test known as the Wasserman
+test has been discovered by means of which, through an examination of a
+few drops of blood, any trace of syphilitic poison which exists in the
+body may usually be detected. This is true even though the individual may
+at the time show no visible symptoms of syphilis. The test is therefore of
+great value in detecting the latent germs of syphilis in individuals who
+have apparently been cured, and also often in making an early diagnosis of
+paresis. The Wasserman test, however, is reliable only in the hands of a
+skilled operator. It may occasionally give a positive reaction when
+syphilis does not exist and on the contrary a negative when it is present.
+The _luetin_ test is also now applied by some specialists, but is too new
+a test to have come into general use. It works on the same principle as
+the tuberculin test for tuberculosis. Some army physicians now also give
+what is termed a provocative Wasserman. That is, in a suspicious case
+which gives only negative results by an ordinary Wasserman, they can get,
+if syphilis really exists, a positive reaction after giving small doses of
+potassium iodide or salvarsan.
+
+It should be well understood by every one that syphilis is usually curable
+provided the patient is given modern scientific treatment by a _competent_
+physician. I emphasize competent because there are so many quacks in this
+field that one undergoing treatment can not be too careful in assuring
+himself of the competency of the physician. In even a case of long
+standing, where the symptoms have been in abeyance for a number of years,
+the disease can be cured provided it has not developed into an active
+cerebro-spinal type, and even the latter can be much benefited by proper
+treatment. The great danger of the cerebro-spinal type is that it will
+result in paresis or locomotor ataxia.
+
+As long as the blood of a patient shows a _positive_ Wasserman reaction,
+marriage should certainly not be consummated. If after a proper course of
+treatment by a well-informed physician, the patient shows a _negative_
+Wasserman when tested by a competent examiner, he probably would not
+infect his wife or offspring, although prudence would require that he wait
+at least six months or a year before marriage, and marrying then only if
+later tests remain negative.
+
+The only way for a patient to be sure that he is not harboring the
+cerebro-spinal form would be to have a spinal puncture made and the
+cerebro-spinal fluid examined. While the cerebro-spinal phase often does
+not occur until long after the primary infection, cases are known in which
+it has appeared within a few weeks. Evidence that the central nervous
+system is frequently invaded early in the course of the disease is
+increasing. Marriage of an individual suffering from the cerebro-spinal
+form should not take place, since such a one is almost sure to become a
+burden on the family or the state.
+
+=Many Syphilitics Are Married.--=It may seem to some that in a treatise on
+being well-born the subject of syphilis might be ignored as not being
+especially pertinent, but the supposition that no considerable percentage
+of syphilitics marry is not borne out by the facts. Seventy-five per cent.
+of men with insanity due to syphilis who are admitted to hospitals are
+married. The insanity in such cases is mainly the result of infections in
+earlier years, often long before marriage. While syphilis, strictly
+speaking, is not inherited, that is, does not become part and parcel of
+the germ-plasm, still the frequency of its direct transmission to
+offspring is so appalling that the outcome, as far as the immediate child
+is concerned, is quite as disastrous as the most thoroughgoing real
+inheritance could be.
+
+=Why Permit Conditions to Continue as They Are?--=When one faces the
+easily ascertained facts regarding venereal disease, it seems incredible
+that we, an intelligent people, can go on complacently handing our
+daughters and sisters over to the surgeon's knife and a life of personal
+misery, and even in not a few instances to become mothers of incurably
+defective children, yet the dire fact confronts us that we do. We can no
+longer excuse ourselves on the plea of ignorance, for the grisly record
+may now be read in many medical and not a few popular treatises, and we
+find the theme entering even into the modern drama, as witness Brieux's
+_Damaged Goods_. Further indifference to these conditions can only be
+attributed to culpable apathy or prudery.
+
+The extreme dangers to which parents are subjecting their daughters if
+they do not demand a clean bill of health on the part of their prospective
+husbands are obvious. Fathers and mothers perfectly willing to inquire
+into their future son-in-law's social connections, his income, securities,
+or business chances become strangely "modest" when it comes to determining
+whether he is physically fit for marriage.
+
+One great cause of ignorance in the past was the prudish taboo against
+frank discussions of venereal diseases which has thrown the veil of
+silence about the subject. To-day, however, it is coming to be recognized
+that these maladies are diseases and not a standard of social propriety,
+and that like most other diseases the surest way to secure prevention and
+gradual eradication is through the enlightenment of the public. They are
+prevalent in all classes of society. Moreover, it must not be forgotten
+that there is no form of venereal disease which may not be innocently
+acquired. Even where acquired through transgression of moral law an
+ignorant attitude toward the sexual instinct is often at the bottom of the
+difficulty.
+
+=Medical Inspection Before Marriage.--=Ante-nuptial medical inspection is
+certainly as necessary to the welfare of society as the certification of
+age and of the single state now required by law. No one objects to a
+medical examination pertaining to venereal and other diseases when it
+comes to taking out a life insurance policy, and why there should be any
+more objection to it as a preliminary to marriage is a mystery. A few
+states already have compulsory ante-nuptial medical inspection. The laws
+have been enacted too recently to judge adequately of their working. There
+has been much debate in Wisconsin as to whether their law (Chapter 738,
+Laws of 1913), which went into effect January 1, 1914, is constitutional
+and whether it requires a Wasserman test. The Wisconsin law applies to
+males only. The Supreme Court of the state has declared it constitutional
+and that its requirement of "the application of the recognized clinical
+and laboratory tests of scientific search" involves only such examination
+as the ordinary licensed physician is equipped to make and can reasonably
+be expected to make for three dollars, the maximum fee specified in the
+law.
+
+A number of the physicians of the state are still dissatisfied with the
+wording, although most do not oppose the principle of the law. Many
+believe that it should apply to the women as well as to the men, and
+others feel that the law should be extended to cover still other kinds of
+marital unfitness. Most of the practitioners with whom I have discussed
+the matter appreciate the motive underlying the law and are endeavoring to
+make it successful.
+
+The general public of the state as a whole seems to be in favor of the
+provision. At least one hears much favorable comment and little
+dissension among those who understand its purpose. The very controversy
+over it which sprang up after its passage proved to be of great benefit in
+the education of the public regarding the necessity of such measures. Such
+physicians as I have been able to question report that the candidates for
+marriage rarely object to the requirement, but on the contrary strongly
+favor it. Especially where they have suffered from venereal disease
+earlier in life most are eager to know their condition and to have medical
+advice. To my own mind this last fact is the most significant of all, as
+it will give every candidate for marriage a chance to know the truth. Most
+men are not so much brutal or vicious as ignorant in such matters. The
+vast majority of those unfit for marriage as a consequence of venereal
+disease will, when they realize the danger their condition imposes on wife
+and children, take every possible means to put themselves into proper
+condition.
+
+Desirable as the Wasserman test may be, it requires special laboratory
+facilities and equipment as well as a specially trained examiner to make
+it a reliable test. Moreover it can not be given by the general
+practitioner for the very moderate fee that must obtain in a pre-nuptial
+examination compelled by law. If it or the serum test for gonorrhea are to
+be applied then the legislative body of the state will find it necessary
+to establish a special public laboratory or laboratories for their
+application. This, however, is not a matter of particular difficulty and
+would be capital well invested in any state.
+
+=The Perils of Venereal Disease Must Be Prevented at Any Cost.--=However,
+no matter what the cost may be to the state, no matter what the exaction
+from the individual, the grave perils of venereal disease to society
+_must_ be prevented. We owe it to the cause of humanity that there be
+fewer victims born into a world of eternal night, that from a parentage of
+polluted blood there spring no longer hosts of children with feeble
+misshapen bodies or with tarnished intellects, death-marked at the door of
+life.
+
+=Bad Environment Can Wreck Good Germ-Plasm.--=In conclusion it is evident
+from our discussion of prenatal influences that not all of being well-born
+is concerned with heredity in its proper sense, since the unborn young may
+be influenced either directly or indirectly by environmental conditions
+which are in no sense products of heredity, although as far as the
+immediate child is concerned the result may be quite as disastrous where
+the influence is a baneful one. As to the production of beneficial
+prenatal effects, while parents can do nothing toward modifying favorably
+such qualities as are predetermined in their germ-plasm, nevertheless they
+must come to realize that bad environment can wreck good germ-plasm. They
+can see to it that they keep themselves in good physical condition by
+wholesome temperate living, and thereby insure as far as possible healthy
+germ-cells for the conception and good nutrition for the sustenance of
+their progeny. Their one sacred obligation to the immortal germ-plasm of
+which they are the trustees is to see that they hand it on with its
+maximal possibilities undimmed by innutrition, poisons or vice.
+
+
+
+
+CHAPTER VII
+
+RESPONSIBILITY FOR CONDUCT
+
+
+Since both physical and mental attributes are unquestionably inherited, it
+becomes a matter of importance to inquire into the nature of the entity we
+call personality. To what extent is human conduct a product of parentage?
+Although apparently free agents are we in reality only by infinitely
+subtle indirections making the responses, forming the habits, establishing
+the characters which result merely from the blind impulsions of an
+inherent constitution? If so, who is praiseworthy, who blameworthy? Are
+men
+
+  "But helpless pieces of the Game He plays
+  Upon this chequer-board of Nights and Days."
+
+=All Mental Process Accompanied by Neural Process.--=Whatever the ultimate
+decision of psychologists may be regarding the relation of mind to the
+sensory and nervous mechanism of man it is certain that there is so close
+an association between them that the least alteration in the mechanism
+means a parallel effect in the mind, or in the words of Huxley, "every
+psychosis is definitely correlated with a neurosis." The rind or _cortex_
+of gray matter which constitutes the surface of the large cerebral
+hemispheres of the human brain is regarded as the seat of consciousness.
+The development of the mental powers in the infant is dependent on the
+development of the elements of this cortical substance and the waning of
+the mental faculties in old age goes hand in hand with its atrophy.
+Abnormal arrangements, injuries or omissions in it mean mental
+unsoundness. How the activity of the structural mechanism gives a reaction
+in consciousness is not understood, but we know that in the living being
+the two phenomena are inseparably linked. Whether we accept the hypothesis
+that consciousness is an actual product of the structural mechanism or the
+hypothesis that the latter is only an instrument for the manifestations as
+consciousness of an outside force or entity, just as the telegraphic
+instrument manifests the existence of electricity, is neither here nor
+there for our purposes. On either supposition the degree and manner of
+expression are determined by the structure of the mechanism. Our main
+problem is to decide as nearly as possible how much of the mechanism is
+rigidly inherited, how much is at birth largely undestined, so that its
+ultimate outcome is in part a product of the forces which play upon it, or
+in other words of education and training.
+
+=Gradation in Nervous Response from Lower Organisms to Man.--=To
+comprehend fully the basic nature of human neural responses one must seek
+the roots in the behavior of lower organisms. For there is found in a
+simpler form many of the fundamental activities and the first dim gropings
+which emerge in man as memory, reason and will. As we ascend the scale of
+animal life we find a continuous advance in neural complexity and nervous
+response that in many respects grades up closely to the human type.
+
+A windmill or a weather-vane points toward the source of the wind,
+obviously not because either exercises any special choice in the matter,
+but because it is constructed on such lines of symmetry that when the wind
+strikes it, if it slants the slightest to left or right, the more exposed
+surface receives the greatest pressure and thus swings the body back into
+the line of least resistance.
+
+=Behavior of Many Animals Often an Automatic Adjustment to Simple External
+Agents.--=It is a far cry, of course, from the responses of such a machine
+as a windmill to the responses of even the simplest living thing, but in
+spite of the broad gap between the two, there is much reason to believe
+that the behavior of many living organisms is due in a marked degree to
+the directive effects of comparatively simple external factors rather than
+to the complex internal volitions the casual observer is likely to
+attribute to them.
+
+=Tropisms.--=It is a marked characteristic of all living protoplasm that
+it has the power of responding to external stimuli. This power of response
+is termed _excitability_ or _irritability_. In describing the motor
+responses of living organisms to stimuli resulting from a change in
+surroundings the term _tropism_ (Gr. _Trope_, turning) is frequently used
+and the kind of stimulus is indicated by a prefix. Thus the term
+phototropism means a turning or _orientation_ brought about by means of
+light. An organism which reacts by a movement toward the source of light
+is said to be _positively phototropic_, one which moves away from it,
+_negatively phototropic_. By using such a neutral terminology the
+physiologist avoids implying that necessarily "likes" or "dislikes" or any
+other psychic reaction enter into the movements.
+
+Several kinds of tropisms are recognized, such as _phototropism_ or
+_heliotropism_, reaction to light; _thermotropism_, reaction to heat;
+_electrotropism_ or _galvanotropism_, to electric current; _geotropism_,
+to gravity; _chemotropism_, to a chemical; _rheotropism_, to current;
+_thigmotropism_ or _stereotropism_, to contact; and _chromotropism_, to
+color.
+
+=Many Animals Show Tropic Responses.--=Many of the lower animals seem to
+have their movements determined more or less mechanically by the action of
+such external factors, some being positively, others negatively responsive
+to a given kind of stimulus, or the same individual may be at one time
+positive, at another negative, according to modifying conditions to be
+mentioned presently.
+
+In plants and in simpler lower animals there is no special nervous system.
+The responses of these organisms depend on the general irritability of
+their constituent protoplasm. In other animals a nervous system is
+developed, crude and diffuse in lower forms, extremely delicate, complex
+and definitely ordered in higher forms. But it should be borne in mind
+that nerve protoplasm possesses only in high degree a capacity for
+irritability, conduction, etc., that is common to all living substance. In
+keeping with other "physiological divisions of labor" or specialization
+which mark the increasing complexity of animals, this enormously enhanced
+sensitivity and conductivity of certain tissues have come about, and they
+have become set apart for these special functions. In higher animals,
+therefore, the tropisms where operative must act more or less through the
+agency of the nervous system instead of directly through the general
+protoplasm of the organism.
+
+=Certain Apparently Complex Volitions Probably Only Tropisms.--=Where
+nervous systems enter into tropic responses there must be specific
+sensibility of certain nerve terminations (i. e., sense organs) at the
+surface of the body. These sensory or receiving nerves connect through the
+central system with corresponding motor nerves which in turn supply
+certain specific muscles through the contraction of which the organism is
+as surely and as mechanically oriented as in the simpler cases. For
+example, if light is the stimulating agent, when it strikes a positively
+phototropic animal, if the latter is not already oriented, the eyes or
+other nerve terminations sensitive to light transmit an impulse through
+the central nervous system to certain muscles causing them to increase
+their tension and thereby swing the animal around with its head toward the
+light. Progressive movements which the organism then makes must carry it
+toward the source of light. Thus it is not "love of light" that draws the
+moth into the flame but the mechanical steering of the body toward the
+source of light through the stimulations produced by the light waves. It
+is chemotropism, not solicitude for its offspring, which drives the flesh
+fly to lay its eggs on decaying meat. And it is stereotropism and not a
+desire for concealment which impels certain animals such as many worms
+and insects to get into a close contact with solid bodies, or in other
+words to "hide" themselves in burrows and crevices.
+
+=Complicating Factors.--=However, beautifully as these theories of
+tropisms work out in a broad general way, there are various additional
+factors entering which must be reckoned with, and these become more
+numerous and of more consequence as the organism becomes more complex. In
+the first place certain internal conditions must be considered. Living
+matter is characterized by its instability. There are continual synthetic
+and disruptive processes in progress which the physiologist terms
+metabolic changes. The very "life" of such matter seems to be the
+manifestation of such changes. Concerning what the ultimate source of
+these changes is, whether or not indirectly they may be referred to
+external conditions as seems probable to many biologists, no one so far
+has ever given a convincing, positive answer. It is sufficient for our
+purposes to know that they may have set up certain internal stimuli which
+may modify the behavior of the organism in which they reside, and that the
+"physiological state" of the organism at the time of external or internal
+stimulation will condition the response. This physiological condition may
+be dependent on the general metabolic equilibrium of the animal, or on the
+extent of previous stimulation by means of the same or different agents.
+Thus the organism may not always react in the same way to the same
+stimulus.
+
+The intensity of the stimulation and change in the intensity of the
+stimulation, are also factors to be reckoned with. Moreover, it must be
+taken into account that a given organism is often operating under the
+control of more than one external influence. For example, swarm spores in
+a dish of water which at a given temperature are positively phototropic,
+that is, gather at the side of the dish toward the light, may, if the
+temperature of the water is raised or in case of marine forms if the
+salinity is increased, become negatively phototropic. Sometimes two or
+more forms of stimuli may cooperate in bringing about certain behavior as,
+for instance, in the reaction of the earthworm to a suitable habitat,
+through a combination of chemical and contact stimuli. On the other hand,
+two different stimuli may interfere with each other; for example, the
+usual phototropic responses of certain animals do not manifest themselves
+when they are mating or feeding. In short, anything that alters the
+physiological state of the organism may cause it to react in a different
+manner. And thus with the interplay of shifting external agents and
+variable internal state the bounds of behavior on these purely mechanical
+bases become considerably extended.
+
+=Many Tropic Responses Apparently Purposeful.--=The query arises as to why
+if these responses are mechanical they are so often apparently purposive;
+that is, why do they so often subserve some useful end for the animal?
+While they do not always work out to the animal's benefit, as for instance
+in the case of the moth and the light or under many other conditions that
+can be devised experimentally, as a matter of fact under normal natural
+conditions they are on the whole useful to the organism, carrying it
+into suitable surroundings of food, lessened danger, temperature, and the
+like.
+
+The probabilities are that in their first origin the reactions were not
+purposive. However, if any proved harmful they would result in the
+extermination of their possessors and hence of that particular strain of
+individuals. Those types that happened to have useful reactions would be
+left and in course of time as the process of eliminating the others went
+on, would become the prevailing types. Any organism which the useful
+reaction had preserved would tend to hand it down to the succeeding
+generation where again it would be the conserver of those individuals
+which possessed it in sufficient degree.
+
+=Authorities Not Agreed on Details of Tropic Responses.--=Although all the
+foremost modern students of animal behavior accept as facts the more or
+less mechanical orienting effects of external stimuli, there is by no
+means unanimity of opinion regarding details. Some stress as the directive
+factor the continuous action of the stimulating agent on sensitive tissues
+symmetrically situated. Others would maintain that it is the time rate of
+change in the intensity of the stimulating agent, or that the factor is
+different in different cases. Some make much of an automatic sort of
+"trial and error" system by which certain organisms test out an inimical
+environment until the path of least irritation is hit upon as the way to
+safety. The field is a broad one and to get at the finer shades of
+distinction the reader will have to refer to the works of such
+authorities as Loeb, Jennings, Holmes and Mast.
+
+=Tropisms Grade Into Reflex Actions and Instincts.--=The tropisms in many
+cases become indistinguishable from _reflex actions_ and these in turn
+grade up into the _instincts_ of animals. The latter may be looked on as
+but subtler and more involved reactions made possible through a more
+intricate structural organization. As might be expected of instincts, the
+feature of utility is more in evidence than in simpler tropisms because
+they have become of proportionately greater magnitude, but the same
+fundamental mechanism is apparently at bottom of both. It has already been
+seen how the "instinct" of the blow-fly to lay its egg on meat is
+interpretable as a chemotropic response. Thus no elaborate psychic
+mechanism is necessary in such behavior.
+
+=Instincts.--=In the typical instinct there is a series of "chain
+reflexes" in which one step determines the next until mechanically the
+whole gamut of changes is run to the last step. It is characteristic of a
+purely instinctive act that an animal performs it without practise,
+without instruction, and without reason. Moreover, all of the same kind of
+animals tend to perform the act in the same way. But with instincts, as
+with tropisms, the physiological state of the organism must be regarded.
+For instance, the instinctive reactions of an animal sated with food or
+hungry will be different.
+
+=Adjustability of Instincts Opens the Way for Intelligent Behavior.--=As
+we progress in the scale of animal life this adjustability of instincts
+to new conditions comes more into evidence. While prescribed in the main
+by internal impulse the carrying out of the action is capable of some
+adaptability to circumstances. And in proportion as this adaptability
+releases the organism from a blind rigid working-out of a predetermined
+end, there is opened up the possibility of intelligent behavior; that is,
+of modification of the instinctive behavior by individually acquired
+experience.
+
+While the generation of instinctive impulses still occurs it is left more
+for individual experience to teach discrimination between ends. But we can
+not escape a fundamental structural mechanism, for with this new capacity
+of educability must come new structural mechanisms in the nervous system
+and this must be as faithfully reproduced in each individual as is the
+basis for any other nervous response. How low in the scale of animal life
+animals can profit from their experiences to the extent that their future
+conduct is conditioned thereby is not known. Some would place it as far
+back as the protozoa, others would not. Where such modification of
+behavior is possible there must be some mechanism for the storage of
+impressions in the form of what we term _memory_.
+
+=Modification of Habits Possible in Lower Animals.--=Among invertebrates
+such animals as crayfish will acquire new habits, or rather will modify
+old ones. Even as lowly an organism as the starfish can have changes of
+habit thrust on it. When a starfish is placed upon its back it rights
+itself by means of its arms or rays. Professor Jennings found that in a
+given individual the tendency was always to employ certain rays for this
+rather than others. However, by preventing the use of the rays customarily
+employed, he found that the animal would use a different pair and that
+ultimately in this way it could be trained into the habit of using this
+pair of rays even when restrained in no way. One starfish which was given
+one hundred eighty such lessons in eighteen days after an interval of
+seven days still retained the new habit; young individuals were found to
+be more easily trained than old ones.
+
+=Some Lower Vertebrates Profit by Experience.--=Among vertebrates it is
+known that those as low in organization as fish will profit by experience.
+They will learn to come for food at a regular time and apparently learn
+more or less to appreciate the presence of certain obstacles with which
+they have had unsatisfactory experiences. Professor Sanford sums up what
+he believes are the limitations of the piscine mental organization as
+follows: "No fish is ever conscious of himself; he never thinks of himself
+as doing this or that, or feeling in this way or that way. The whole
+direction of the mind is outward. He has no language and so can not think
+in verbal terms; he never names anything; he never talks to himself; as
+Huxley says of the crayfish, he 'has nothing to say to himself or any one
+else.' He does not reflect; he makes no generalizations. All his thinking
+is in the present and in concrete terms. He has no voluntary attention, no
+volition in the true sense, no self-control."
+
+=Rational Behavior.--=Finally, however, out of these first dull
+glimmerings of intelligence as exemplified in the higher invertebrates
+and the lower vertebrates, which can modify behavior as the result of
+experience, come the still higher factors so dominant in man, of
+_rational_ behavior. This higher mental process can realize the end to be
+reached and can deliberate on the means to be employed. By means of his
+_reason_ man can overcome difficulties in advance by "thinking" out
+suitable schemes of action. Some naturalists believe that man stands alone
+in possessing the power to reason, although others believe that some of
+the other mammals, notably the other primates, possess the same attribute
+although in a much less degree.
+
+=Conceptual Thought Probably an Outgrowth of Simpler Psychic States.--=Is
+the capacity for such conceptual thought, however, which appears as the
+final efflorescence of complex neural activity something entirely new?
+Most students of comparative psychology maintain that it is not. Just as
+one kind of an instinct frequently grows out of another, so has this grown
+out of the complex of _psychic_ states which preceded it. It apparently is
+the product of the increasing awareness on the part of animals of their
+neural processes and the outcome of these processes, which becomes more
+and more prominent as we ascend the scale of animal life. With the advent
+of associative memory the mind comes more and more to deal with attributes
+of objects instead of merely with each single concrete object as it
+presents itself, and these attributes being common to many objects, come
+to represent definite ideas which can be manipulated by the mind.
+Language, of course, has been an indispensable aid to man in this regard,
+for words become descriptions of facts and symbols of concepts, and
+thereby allow of abstract thought.
+
+=The Capacity for Alternative Action in High Animals Renders Possible More
+Than One Form of Behavior.--=With this modification of instinct by
+experience made possible, there comes at the same time, of course, the
+capacity for a rational instead of a purely instinctive behavior. This
+very capacity for alternative action opens up many new possibilities of
+behavior and together with the well-known fixative effects of habit, also
+the opportunity of permanently establishing certain ones. Thus it is
+obvious that a behavior toward which in a strict sense there can not be
+said to have been an original specific tendency, can be developed. What
+was present in the first place was only a general possibility of the
+development of any one of several types of behavior. The final choice of
+the alternatives together with repetition makes it the habitual behavior
+of the individual. Of course it can be urged that if the selection of the
+type of behavior is left to the individual then the latter will operate
+automatically toward the various impulsions of its neural make-up and one
+path will be followed because of stronger inclination in that direction,
+so that the whole procedure is in the end the mere operation of an
+automaton. But however this may be in the individual left to itself, the
+fact is in man that the young individual is never left to itself and in
+the nature of things can not be, so that without entering into this
+troubled pool of controversy regarding freedom of the will, I wish merely
+to point out that the possibility of more than one form of behavior
+exists and that if one is more desirable than the others then this one can
+be chosen by the ones responsible for the training of the young individual
+and clenched fast by the agency of habit.
+
+Intelligence, reason and habits, however, no less than instincts and
+tropism must have neural as well as psychical existence and we can not
+escape therefore the underlying mechanism.
+
+=The Elemental Units of the Nervous System Are the Same in Lower and
+Higher Animals.--=It is interesting to note that the fundamental neural
+mechanism which underlies the mental processes of higher animals is not
+essentially different from that which serves in lower forms. Although as
+animals become more complex their nervous systems have become
+proportionately larger and incomparably more intricate, still all the
+changes have been rung on the same basic neural unit, the _neuron_ or
+nerve-cell (Fig. 32_A_, p. 209). The higher nervous system differs from
+the lower in the number, in the specializations and in the associations of
+these units rather than in possessing something of entirely different
+elemental structure.
+
+=Neuron Theory.--=According to the prevailing modern conception the entire
+nervous system is made up of a series of units called _neurons_. Each
+neuron is a single cell with all its processes. The latter consists
+typically of short branching processes on the one hand, known as
+_dendrites_, and of a single process on the other, known as the _axon_,
+which extends from the cell to become a nerve fiber (Fig. 32, p. 209). The
+various neurons, with possibly a few exceptions, are not anatomically
+continuous but contiguous. They communicate with one another apparently by
+contact only. The axon of each neuron ends in an elaborate series of fine
+branchings which lie in contact with the dendrites of another neuron, or
+in some cases with the body of the other cell (Fig. 32, p. 209). Thus the
+nervous impulse passes from one neuron to the other at these points of
+contact. An impulse is supposed to travel normally only in one direction
+through a neuron, the dendrites being the receiving and the axon the
+discharging terminals. There are various types of neurons. Some,
+particularly within the brain, have their main processes so provided with
+branches and brushes that they may come into physiological connection with
+a number of other neurons.
+
+
+[Illustration: FIG. 32
+
+A--Diagram to illustrate neurons and their method of connection; _a_,
+axon; _d_, dendrite; _s_, synapse. To simplify the diagram the medullary
+sheathes of such fibers as would have them have been omitted. The arrows
+indicate the direction in which the impulse travels. The lower series
+shows diagrammatically how from the same neuron in the cortex two
+subordinate neurons may be affected, the one excited to cause contraction
+of a certain group of muscle fibers, the other inhibited so that the
+antagonistic fibers may relax and thus not hinder the movement of a given
+part.
+
+B--Section of a region of the cerebral cortex (after Cajal). The cells
+have been blackened with chrome-silver and are much less highly magnified
+than the diagrams in A. The numerals refer to certain characteristic
+layers of the cortex in this region.]
+
+
+=Establishment of Pathways Through the Nervous System.--=It is believed
+that more or less resistance to transmission of stimuli prevails at the
+point of contact (_synapse_) between two neurons but that this resistance
+is lessened by repetition of conduction. The frequent traversing of a
+given pathway by similar impulses finally results in an automatic
+occurrence of the transmission, or, in other words, the action becomes
+habitual. Education consists largely in establishing such routes through
+the nervous tissue. Because of the greater plasticity of the neural
+mechanism in youth it is easier to open up and fix pathways of conduction
+than in later years. Moreover the earlier established lines of conduction
+become the more permanent.
+
+=Characteristic Arrangements of Nerve Cells Are as Subject to Inheritance
+as Other Structures of the Body.--=That the main features of the nervous
+system are inherited becomes obvious when we see that each kind of animal
+has its own distinctive numbers, arrangements and proportions of the
+various neural units. In man, for example, there are certain
+characteristics, types and groupings of nerve-cells which are reproduced
+generation after generation with remarkable fidelity. This means that in
+so far as these represent the mental make-up of the individual, his
+mentality is continuously linked with others which have gone before. The
+new-born child has all the nerve-cells in its brain that it will ever have
+but the ultimate linkages of the finer connectives between them, or at
+least the pathways of travel, remain in large measure to be made.
+
+As we have already seen, the cerebral cortex is the seat of the chief
+mental faculties of man or at least of the highest of these. Professor
+Lloyd Morgan, one of our greatest authorities on comparative psychology,
+is inclined to believe that the instincts are located in the subcortical
+material. In any event, the inheritance of mental ability resolves itself
+into the inheritance of a certain cerebral mechanism.
+
+=Different Parts of the Cortex Yield Different Reactions.--=The cerebral
+cortex, however, is not functionally homogeneous throughout. Certain
+regions have been shown to be motor, others sensory, and moreover, these
+regions are apparently further specialized so that a given one of them is
+associated with a specific type of sensory or motor response, not merely
+with responses in general. Thus by injuring one of the sensory areas we
+might destroy vision but not other sensations, or by stimulating one of
+the motor centers we would get a response in a corresponding motor organ
+but not in all such organs. Likewise, it is probable that still different
+areas, the so-called "association areas," relatively of much greater
+development in man than in any other animal, are the regions in which
+various perceptions and conceptions are synthesized and formed into
+organized knowledge. Here also are engendered the volitions which when
+flashed through the motor centers become expressed in activity or
+behavior.
+
+It seems highly probable that just as the sensory and motor areas differ
+in kind from one another, so we must suppose there are qualitative
+differences in various parts of the association areas so that the
+different parts give different reactions in consciousness; that is, each
+special mental ability of the individual is more or less centered in a
+special part of the cortex. And just as there may be variations in other
+structures of the organism so there may be variations in these areas. The
+"gifted" person in some one direction, whether it be in mathematics,
+music, painting, or what not, is on this hypothesis one who has that
+particular area of his brain which forms the basis for the talent in
+question more highly developed than it is in the average individual. And
+since such talents are handed down to descendants, this can only mean that
+a similar grouping of the neurons in the region in question has occurred.
+
+=Skill Acquired in One Special Branch of Learning Probably Not Transferred
+to Another Branch.--=Such a differential arrangement of the
+brain-mechanism which presumably underlies the various mental abilities
+would lead to the inference that skill in one special branch of learning,
+in so far as it involves only certain centers of the cortex, would not be
+transferred to another branch based on different neural pathways and
+centers. Development of historical knowledge, for example, would not
+enhance one's mathematical ability, or vice versa. The testimony of
+various psychologists bears out this idea. In so far as certain factors of
+training, such as habits of industry, concentration, etc., are common to
+the study of either mathematics or history, the good effects of either
+discipline will probably be much the same, but the identity of effect
+vanishes as soon as the intrinsic characteristics of the subjects
+themselves are involved.
+
+Just how far we are warranted, however, in carrying this idea of localized
+functions as regards the association areas is a moot question. Our present
+attitude regarding the specificity of such localizations is largely a
+matter of inference based on analogy to conditions which obtain in other
+and better known parts of the brain, together with the indubitable
+differences in inborn abilities which exist between individuals. Some few
+brain physiologists maintain that the whole cortex operates more or less
+as a unit in all of the higher psychical activities.
+
+=Preponderance of Cortex in Highest Animals.--=One of the most interesting
+conditions in the nervous system of the highest types of animals is the
+way in which the cortex has outrun the other parts of the brain in size
+and complexity and has come to dominate the organism more and more both
+directly and indirectly. Aside from the proportionately greater increase
+in size of the cortex, there is an abundance of anatomical evidence of
+this altered and probably altering system of control in man and the higher
+apes. This is well illustrated in the fiber tracts (nerve bundles) of the
+spinal cord.
+
+=More Long Fiber Tracts in the Spinal Cord of Man.--=The spinal cord
+although having many nerve centers of its own is also in great part a
+large cable for conducting enormous numbers of fibers from one part of the
+cord to another, or to and from the brain. In man and the higher apes a
+considerably larger percentage of the total area of the cord is given up
+to the long fiber tracts from the brain to the body than in lower
+vertebrates. This progressive increase in long fiber tracts in the higher
+anthropoids probably marks more and more domination of the body by the
+higher brain centers and correspondingly less by the direct activity of
+the cord and by the lower brain centers. However, even in man, many of the
+simpler reflexes of the body still have their centers in the spinal cord.
+
+=Special Fiber Tracts in the Cord of Man and Higher Apes.--=There are
+certain special tracts of the cord that are particularly interesting in
+connection with the increasing domination of the brain over the body,
+namely, the _pyramidal tracts_. These were the latest tracts to appear in
+the animal kingdom and are apparently the latest to become functional in
+the individual. It is believed that the development of the medullary
+substance (an enveloping sheath) of the common medullated nerve fiber
+marks the time of entrance of the fiber into activity and it is a
+significant fact that the formation of this sheath occurs last of all in
+the fibers of the pyramidal tracts, where it does not appear till after
+birth. These tracts convey impulses from the brain to the body. They
+consist of two sets of tracts, in fact, one the crossed, the other the
+direct. As an anomaly, probably arising most frequently from instrumental
+injury at birth, the pyramidal tracts fail to develop normally, with the
+distressing result that the infant, although possessing perfectly normal
+brain activity and normal spinal cord reflexes, is unable to exercise
+voluntary control of the body. In other words the condition, like
+hare-lip, is one of suppressed development. At least this seems to be the
+most plausible explanation of what is known as _Little's disease_. Such
+unfortunates usually die early although they may survive for a few years.
+
+The direct pyramidal tracts occur only in man and man-like apes. They vary
+considerably in extent in different individuals. They originate in nests
+of characteristic large cells located in the cerebral cortex and are
+regarded as paths, though not the only ones, through which volitional
+impulses are conveyed from the brain. They seem to control certain of the
+finer and more delicate movements of the body.
+
+=Great Complexity in Associations and More Neurons in the Brain of Man
+Than of Other Animals.--=It has already been noted that as animals stand
+higher in the scale of life while the general plan of their neural
+elements remain the same, there is increasing complexity in the number and
+connections of the neurons. The number of processes on individual
+nerve-cells is also greater. There is in fact much greater complexity in
+the number of processes and the inter-connections of the neural cells
+than in the numbers of the cells themselves. This would seem to indicate
+that the greater mental activities of higher animals depend more on
+richness in complex associations than on mere increase in number of
+neurons. The latter, however, is by no means unimportant as may be seen in
+man, for instance, in whom it is estimated that the cerebral cortex, that
+is, that part of his brain in which his more complex mental processes
+transpire, contains some nine billion more nerve cells than does the
+corresponding region of the brain of an anthropoid ape.
+
+Of especial significance in the psychic make-up of man is his vastly
+increased capacity for inhibition. Although not possessed by all men in
+equal measure and not entirely wanting in lower animals it is a
+distinctive feature in all human conduct. Much of any child's education,
+particularly as it pertains to behavior, must be concerned with training
+in the exercise of proper inhibitions. He must learn to suppress certain
+primitive types of reaction in favor of higher ones. This applies not only
+to motor activities but to trains of thought as well. The essence of
+self-control consists mainly in ability to substitute for one impulse or
+idea other compensating ones. And the secret of concentration lies in
+being able to banish irrelevant ideas and focus on the central thought.
+
+=The Nervous System in the Main Already Staged at the Time of Birth for
+the Part It Must Play.--=It is clear from what is known of its anatomy
+that in the main the central nervous system is framed to respond in
+certain set ways, that there are determinative elements in it which
+control or determine the responses, and therefore the behavior of the
+body. The same evidence shows also, however, in the incompleteness of many
+of the associations, that while the stage is all set and some of the main
+features of the performance are determined at the time of birth,
+considerable yet remains to be done toward fitting the parts together and
+working up the detail. Just exactly what and how much is rigidly
+determined no one knows.
+
+=Many Pathways of Conduction Not Established at Birth.--=As we have
+already seen the evidence is that many of the neural pathways are not yet
+fully established at birth, and there is some indication that routes once
+opened may be altered. To what degree this has bearing on behavior is
+still unknown, but since neurologists attribute so much importance to the
+richness and the associations of the cell-outgrowths, it is evident that
+this increase in the number of pathways after birth with possible
+alternatives of connections may be a very important factor in the
+modification of behavior. Yet, on the other hand, we are completely in the
+dark as to what extent these later associations are predetermined in the
+earlier cells.
+
+=The Extent of the Zone That Can Be Modified Is Unknown.--=There is little
+doubt that many of the paths of action are already firmly established.
+Others, although not irrevocably fixed, offer the least resistance and
+would "naturally" be taken if not counteracted or modified by the more or
+less artificial development and fixation of other paths through
+cultivation and habit. Yet others perhaps are largely neutral; they still
+await the initial decisive push which "choice" or external environment may
+mete out to them. As trainers of youth all that is left that we can do is
+to attempt to develop in certain ways the elements of this indefinite,
+impressible zone. Unfortunately, we must labor in the dark to a great
+extent as we have all too little indication of which the malleable factors
+of intellect and conduct are. We can only infer from long, intelligent and
+sympathetic observation of children in successive stages of their
+development. It is only by having clearly in mind the nature of our
+problem that our conclusions will finally come to be of enhanced practical
+value in the training of children. Observation to the present time clearly
+indicates that many children are strongly predisposed this way or that "as
+the sparks fly upward."
+
+This is a point too frequently overlooked by educators. They are often
+unduly actuated by the other piece of the truth that, "as the twig is bent
+the tree inclines." They sometimes fail to realize that after all the tree
+remains the same kind of a tree. If an apple tree, while it may be bent
+from the normal path of development, it can not produce other fruit than
+apples. Just how much the destiny of man can be influenced by training and
+the exercise of his own will power is the fundamental question not only of
+pedagogy but of ethics as well. For if man's rational judgments are
+markedly conditioned by his neural make-up then the volitional judgments
+which underlie conduct are likewise conditioned since they are
+inextricably intermingled with his reason. We must believe that to a
+considerable extent emotional expression, as well as other mental
+functions, is due to hereditary dispositions of the neurons in the
+various parts of the brain.
+
+=Various Possibilities of Reaction in the Child.--=Despite the innate
+predeterminations of the tree, it is nevertheless our province to see that
+the twig _is_ bent, but our work can only be done with due intelligence
+when we recognize something of the limitations of our material. Of the
+various possibilities of reaction we must see that certain desirable ones
+are realized, even, in some cases, if only to have others thereby
+excluded. It is a commonplace of psychology that all cerebral excitations,
+no matter what the origin, must vent themselves in some way and if this
+expression is not directed into proper channels it will very likely find
+improper ones. We must see that the young wearer of the coat of
+undetermined capacities gets it set by repeated performance into the
+habitual wrinkles of normal social conduct. For it is a trite observation
+that when habits are once well established it requires tremendous efforts
+to do otherwise than as they dictate. There is not the least doubt that
+some of our subjects will respond much more readily to training in certain
+directions of habitual reactions than others, but we have always the
+consolatory knowledge that no matter how difficult the art may be at
+first, repetition reduces the difficulty.
+
+While much of any youth's character must be determined by external forces
+brought to bear upon it, the ultimate climax of our effort and measure of
+our success will be the extent to which we have engendered in him the
+capacity for initiating and carrying out through his own volition those
+impulsions and inhibitions which tend to the highest good of humanity.
+
+=Probable Origin of Altruistic Human Conduct.--=Those phases of human
+conduct which find expression in consideration for others seem no less
+than other mental attributes to have their origin in certain fundamental
+instincts. Altruistic conduct, in last analysis, apparently resolves
+itself back largely to certain very fundamental impulsions, namely those
+which arise out of certain obligations for the welfare of others which are
+necessarily associated with the marital, parental and filial relations
+that must exist where the young require post-natal care. Looked at from
+the standpoint of natural selection, this would come about as a mere
+matter of survival value. Where the young, as in man, are helpless for a
+long period of time, more opportunity would be afforded for the
+development of both conjugal and filial affection. The sympathetic
+emotions once established in such family relations would partly through
+habit, partly through community of interest, readily become extended to
+clan or tribe and as a final consummation to all mankind.
+
+=Training in Motive Necessary.--=In the training of children, then, we
+must recognize first of all that there are decided inclinations or bents
+which, as long as they are not anti-social in nature, must be respected if
+not always encouraged. While it is necessary to utilize these as much as
+possible in their training still we must bear in mind that although it is
+natural for a child to follow certain interests, the fact remains that as
+regards social worth these natural interests may not be the most valuable.
+When this is true we must strive to develop others which will compel
+attention and thus become impelling factors in conduct. Where certain
+fundamental impulsions run contrary to the common welfare it is necessary
+to practise the child in the setting up of inhibitions or counter-impulses
+until this becomes habitual. He must be led to construct a protective
+mantle of appropriate scruples, doubts and fears. It is all important to
+get the proper motives for action to prevail in his mind.
+
+=Actual Practise in Carrying Out Projects Is All Important.--=But on the
+other hand it is equally important to see that the action is effectively
+carried out. In the matter of self-discipline, particularly, we may have
+many ideal impulses and realize that they should prevail over certain of
+our natural propensities, but unless we put forth effort to overcome the
+propensities our ideal impulses are of no avail. The world has many such
+moral paralytics to-day who can not seize their "languor as it were a
+curling snake and cast it off." It is training in this very overcoming of
+reluctance, in this putting forth of actual effort toward worthy ends
+instead of merely memorizing precepts about the desirability of such
+accomplishments, that is so sadly lacking in our school and home life
+to-day. We prate of the importance of self-control, we say with our lips
+that the way to learn to do is by doing, we proclaim that it is more vital
+to instil good mental and physical habits into our pupils than to stock
+them with information, we preach that mere fact training is as conducive
+to making a first-class rascal as an upright man, yet we jog on
+complacently in the well-beaten ruts of memory routine which require the
+memorizing of symbols rather than real understanding. We seldom require
+that our protégés make intelligent judgments based on evidence, we rarely
+exact of them decisions in matters of ethics, and almost never demand that
+they put their knowledge into efficient accomplishment. It can not be too
+strongly urged that we need less of formulæ learned by heart, less dead
+erudition pigeonholed in the brain like so many foreign bodies, and vastly
+more assimilation of knowledge into the living personality of the
+individual.
+
+Where in school or home to-day do we find provision for such training? Our
+tendency is, in fact, just the opposite. According to the modern code, as
+it works out in many instances at least, the child must be taught through
+play. Though it is a truism that he who has not learned obedience can
+never be master of himself, the child of to-day must not be made to obey
+but be wheedled into changing his mind. If a given subject of study proves
+distasteful to him, the fault is the teacher's for not making it
+interesting, for he must always be led on by the thrill of fascination. In
+other words, the child must not only be allowed but be encouraged to take
+the path of least resistance. His own pleasure is to be the standard of
+his actions. Let no stern demands of duty interfere!
+
+Is it any wonder that the products of such tutelage come into the
+activities of life self-indulgent and undisciplined, and although often
+recognizing our private and public shame in business, politics and
+conduct, still remain supine, evasive of the unpleasantness or hardships
+of reform, or inefficient or unwilling in accomplishing unselfish ends?
+
+=Interest and Difficulty Both Essential.--=The writer does not wish to be
+understood as minimizing the importance of interest on the part of the
+child in what he is doing. Interest is undeniably the open sesame to
+desirable mental development; but what he does protest against is that not
+uncommon interpretation of interest which deems it necessary to eschew
+most serious consideration of a subject and evade such parts as present
+difficulties. Certainly if there is any fact that stands out prominently
+in human experience it is the fact that nothing conduces to the
+development of moral stamina so much as the overcoming of difficulties,
+particularly distasteful difficulties.
+
+=Conduct Developed Through Actual Performance.--=Self-control and the will
+to do can be trained and crystallized into habit as well as can any other
+activity. It is a fact that one well grounded in morals by habit will
+successfully resist subconscious impulsions to wrongdoing even when
+suggested in the hypnotic state. Conduct is largely a matter of growth
+through actual performance. For proper guidance of this growth there must,
+of course, be high ideals around which the feelings are led to cluster and
+by which they gradually come to be controlled.
+
+=Construction of Ideals.--=The construction of such ideals through
+example, through precept, through appeal and through actual practise in
+self-denial and self-control on the part of the child, should be the
+foremost duty of the parent or teacher. Above all it should be remembered
+that imitation of teacher, of parents, of companions, is more of a factor
+than intellect in the moral action of children. At present educationally
+we are in a fever for vocational training, for "practical" work, and in
+general for all things conducive to coaching our pupils in how to make a
+living, yet commendable as all this may be, is it not of even more
+fundamental importance to train them how to live?
+
+=The Realization of Certain Possibilities of the Germ Rather Than Others
+Is Subject to Control.--=It may be said in a sense that there exists
+potentially in any germ all the things that can possibly come out of it
+under any obtainable conditions of environment. The very initiation of a
+given mode of expression by some environmental factor, however, often
+mutually excludes many of the others. We get a given average result
+ordinarily because development normally takes place in a given average
+environment.
+
+As may be easily shown by experiment, this is manifest even in the
+instincts of lower animals. In the young the various instincts do not come
+into expression at the same time, and it not infrequently happens that if
+one of the earlier instincts becomes operative toward certain objects or
+situations, later instincts will have a wholly different relation toward
+these objects or situations than they would otherwise have had. As a
+result the whole life conduct of the animal is markedly modified. For
+example, young animals immediately after birth have no instinct of fear.
+They do, however, have a strong instinct to attach themselves to some
+moving thing and follow it. The utility of such an instinct, as for
+instance in the case of young chickens, is obvious. The object of
+attachment is usually the parent, but man may take the place of a parent
+and the young animal will fearlessly follow him about. However if the
+young animal has had no experience with man during its earliest infancy a
+later instinct, that of fear or wildness, will have come into play and it
+will flee from him. It is clear, therefore, that by familiarizing the
+young animal with man before its instinct of fear has come to expression,
+certain habitual reactions are set up in it which inhibit or limit the
+application of its instinct of wildness as regards man. In other words,
+the whole course of its life has been altered by this simple experience.
+The same principle applies in even greater degree to the young of man.
+
+We have seen in a former chapter that what in the ordinary course of
+nature was "predestined" to become one individual nevertheless contained
+the possibility of becoming four or more if the environing conditions were
+made such as to bring about a separation of the cleavage blastomeres. Or a
+fish egg that contained the possibility of becoming a normal two-eyed form
+also contained the possibility of becoming a one-eyed form and could be
+made to do so by certain unusual modifications of the conditions under
+which it develops. However we must not be led so far by the plausibility
+of this comparison that we are misled, for the fact is that we are not
+creating anything new by these environmental upheavals, but are mainly
+altering features that already exist. Beyond doubt the nature of the
+material is of greater import in the specificity of the outcome than are
+the external forces brought to play on it. The only point I wish to make
+is that even what seem ordinarily to be predestined ends can be altered
+by environment, and that the probabilities are that certain features are
+relatively indifferent at their inception, the environmental factor adding
+the final touch of specificity. And our common experience in education
+would indicate that the same is true of mental conditions, including
+behavior. The actual appearance of a particular trait is not necessarily
+always a matter of an initial trend, but may be due merely to the fact
+that its development is possible under certain conditions of environment
+and that these conditions have prevailed in the given instance. And even
+where there is a specific bent it may be arrested through the awakening of
+a contrary impulse, or, on the other hand, its exercise may prevent the
+engendering of the opposite impulse.
+
+=Our Duty to Afford the Opportunity and Provide the Proper Stimuli for the
+Development of Good Traits.--=It is clearly our duty to see that the
+expression of good traits is made possible. We must throw a sheltering
+screen of social environment around the young individual which will fend
+off wrong forms of incitement and chances for harmful expression, and we
+must provide proper stimuli and afford opportunity for development of
+proper modes of expression. We must not forget that a normal instinct
+denied a legitimate outlet will not infrequently find an illegitimate one.
+Above all we must not forget the vital importance of establishing correct
+habits nor the possibility of even replacing undesirable ones by good
+ones. If training can redirect the machine-like behavior of as lowly a
+creature as the starfish into new courses, why should we be so willing as
+some of our genetists would seem to be to throw up our hands and admit
+failure in the case of man before we have even made a rational attempt to
+correct the evils in question? Even in lowly organisms we have seen that
+behavior is not only the result of an innate constitution but also of the
+degree and kind of stimulations to which it has been subjected.
+
+If the individual himself has not the initiative or will to make the
+attempt to set up proper or corrective habits, or to cultivate the
+necessary specific inhibitors, then all the more is it our duty to see
+that he is led by suggestion and drill into the proper routine of
+activities for their establishment. For if the individual with
+propensities toward moral obliquity is to be saved to society it must be
+through the stereotyping effects of good habits.
+
+=Moral Responsibility.--=Beyond question different men have different
+degrees of capacity for mental and moral training. All can not be held
+equally responsible ethically, but the lowermost limit of obligatory
+response to social and ethical demands necessary to rank one as within the
+pale of normal conduct is at such a level that any one not an actual
+defective can in a reasonably wholesome environment surmount it. All
+normal men are responsible for their conduct.
+
+
+
+
+CHAPTER VIII
+
+MENTAL AND NERVOUS DEFECTS
+
+
+Some of the most important and serious problems which confront humanity
+to-day lie in the realm of mental and neural maladjustments. For human
+progress and social welfare are in last analysis based fundamentally on
+the results of normal reactions of human nervous systems. Any serious
+derangement of the latter may, and in certain cases must, lead to more or
+less disaster for the individual and disorder for society of which he is a
+unit. So appalling has the number of neuropathic subjects become in modern
+times that the matter may well cause even the most thoughtless citizen to
+pause and consider.
+
+=Prevalence of Insanity.--=As to the prevalence of insanity, one learns
+from recent charts prepared by a member of the National Committee for
+Mental Hygiene that in 1910 we had more insane (187,454) in our
+institutions than there were students (184,712) in all our colleges and
+universities in the United States, or officers and enlisted men (142,695)
+in our combined United States army, navy and marine corps; further, the
+yearly cost ($32,804,450) of caring for these insane is greater than the
+annual cost of construction ($32,520,100) on such a stupendous undertaking
+as the Panama Canal. In New York over twenty per cent. of the revenues of
+the state go to support the insane. Doctor Lewellys F. Barker, President
+of the National Committee for Mental Hygiene, says: "It is calculated that
+some 250,000 people in the United States are insane. One of every five men
+discharged from the United States army for disability is discharged
+because of insanity, 60 per cent. of the cases being _dementia precox_."
+
+Even in individual states with exceptionally large university populations
+we still find these outnumbered by those of the insane. Thus in Wisconsin
+by 1914 the state university had attained a population of about 4,700
+students resident at the university during the regular school year, and of
+approximately 6,000 attending during some part of the year, but the number
+of insane under restraint in public institutions in the state June 20,
+1912, was 6,851, with an additional 1,284 on parole. This does not include
+the insane in various private sanatoria, and moreover a considerable
+greater number of patients had been treated in these public institutions
+than were resident there June twentieth.
+
+To make such comparisons complete one should, of course, know the average
+length of residence of students in college, and of insane patients in
+institutions. No accurate data on this point are at hand. The average
+period of residence in hospitals for the acutely insane is doubtless
+considerably shorter than the average period of attendance of students in
+college, while on the other hand the average period of residence of
+inmates in asylums for chronic insane is probably considerably longer. For
+example, the Wisconsin State Hospital for the Insane reports a total of
+1,224 patients under treatment, but an average population at any one time
+of only 622 during the year 1911, and the Northern Hospital for the
+Insane, a total of 1,194, with a daily average of 613 during the same
+period. The combined thirty-four county asylums in Wisconsin, for chronic
+insane, had a total population of 5,384 during the year 1911, with a loss
+of 517, or approximately 10 per cent. During 1912 the figures for these
+same institutions run 5,758 and 742 respectively, or a loss of over 12.5
+per cent. The conditions in other states are probably much the same.
+
+In other representative states we find the number of insane in public
+institutions as follows: California, 7,909; Michigan, 7,703; Minnesota,
+5,329; Pennsylvania, 16,992. Epileptics are estimated by alienists to be
+about equal in number to the insane, feeble-minded to be more numerous.
+The estimate that in the United States there are 300,000 feeble-minded is
+probably a minimal figure.
+
+=Imperfect Adjustments of the Brain Mechanism Often Inheritable.--=The
+outside layer or "cortex" of the brain is the region in which the more
+complicated adjustments occur, especially such as pertain to human
+behavior, and inasmuch as this portion of the brain is extremely complex
+and delicate in its mechanism, it is peculiarly liable to derangements
+which, even when slight, may have far-reaching effects.
+
+This brain-mechanism is as much a product of ancestry as is any other
+structure of the body, and it is obvious therefore that imperfect
+adjustments of its structure must be as subject to the laws of
+inheritance as are other malformations of the body. And just as with
+other defects, mental disorders may thus flow from pre-existing ancestral
+maladjustment of the nervous system or from immediate causes thrust upon
+it, such as syphilis, alcoholism, degeneration of the blood vessels and
+traumata. Or, in other words, the mechanism of mentality may be faulty
+from the beginning, or it may be made faulty by bad environmental
+conditions.
+
+The records of the inheritance of insanity, imbecility, feeble-mindedness
+and other forms of nervous and mental defects are truly startling. Active
+researches in this field have been in progress now for several years, and
+as each new set of investigations comes in the tale is always the same. It
+is questionable if there is a single genuine case on record where a normal
+child has been born from a union of two imbeciles. Yet the universal
+tendency is for defective to mate with defective. Davenport gives a list
+of examples, beginning with such a one as this: "A feeble-minded man of
+thirty-eight has a delicate wife who in twenty years has borne him
+nineteen defective children." Little wonder, in the light of such facts as
+these, that the number of degenerates is rapidly increasing in what are
+called civilized countries.
+
+=Many Mental Defectives Married.--=But, it may be urged, these are
+exceptional cases, there is surely no considerable number of mental
+defectives who are married. Let us look at the available facts. In Great
+Britain in 1901, of 60,000 known feeble-minded, imbeciles and idiots,
+19,000 were married, and in the same year, of 117,000 lunatics, 47,000
+were married; that is, a sum-total of 66,000 mentally defective
+individuals were legally multiplying, or had had the opportunity to
+multiply their kind, to say nothing of the unmarried who were known to
+have produced children.
+
+In the state of Wisconsin I note from the tenth biennial report of the
+Board of Control that of 574 patients admitted to the Northern Hospital
+for the Insane during the year from July 1, 1908, to June 30, 1909, 274
+were married and 29 others were known to have been married; this is a
+total of 303 out of 574, considerably over half. At the Wisconsin State
+Hospital for the Insane we find the conditions are no better, for out of
+499 admitted in the year 1909-10, 208 were married and 65 others had at
+some time been married, or a total of 273 out of 499. There is every
+reason to believe that conditions are approximately similar in other
+states.
+
+=Disproportionate Increase in the Number of Mental Defectives.--=Writing
+of conditions in England the Commissioners in Lunacy state in their
+fifty-fourth report that now (1901) there is one officially known lunatic
+to 301.32 individuals of population, whereas in 1859 there was only one to
+536 individuals of population. In Great Britain, taking into account
+mental defectives of all kinds, the 1901 census showed a total of 485,507,
+or 1:85 of total population. Rentoul estimates that 1:50 would be nearer
+the truth because of the fact that the number of officially known mental
+defectives is much less than the actual number. The conditions in Ireland
+are even more impressive, for in 1851 there was one known lunatic to 657
+individuals of population; in 1871, one to 328, and in 1901 one to 178.
+When all allowance is made in these statistics for the greater accuracy of
+recent enumeration, and for other modifying influences, such as migration,
+we are still forced to believe that an alarming increase in insanity is in
+progress and that society is woefully derelict in permitting the marriage
+of such unfortunates.
+
+A census of the insane under public care in Wisconsin June 30, 1910, not
+counting the paroled, shows 6,537, or one to each 357 of population, since
+the population of the state was then 2,333,860. If, however, we should add
+the number of insane in private sanatoria and the number unconfined the
+proportion of normal individuals would be very much reduced.
+
+In the United States as a whole, while I know of no data giving the number
+of married insane, it is estimated that at least one-fourth of the insane
+are not in asylums or hospitals. In all states the number of insane in
+state institutions (there are no available records of most private
+institutions) is rapidly increasing. According to the special census of
+1903 covering a period of fourteen years, during which the general
+population increased thirty per cent., the number of insane in
+institutions increased one hundred per cent. This is due doubtless in part
+to the fact that because of better facilities for keeping them a
+proportionately greater number of insane are being sent to state hospitals
+than in former years. Moreover, improved sanitation has cut down the
+death-rate in asylums. The increase is in such vastly greater proportion
+than the increase in general population, however, that it seems impossible
+to attribute it wholly to the greater accuracy of recent enumerations and
+the increasing custom of confining the insane in asylums. This is a matter
+that demands our gravest attention and one that should be investigated
+with the greatest thoroughness. One of the most disquieting facts in the
+situation in most states is that many patients--an average of
+approximately one thousand a year, in Wisconsin for example--are on parole
+subject to recall. This means that although it is recognized that these
+patients are likely to have to be returned to the asylum or hospital,
+little or no restraint in the meantime is placed on their marital
+relations.[8]
+
+=Protests Voiced by Alienists.--=Is it any wonder under the circumstances
+that we find Doctor Charles Gorst, superintendent at the Mendota Hospital,
+voicing in his 1910 report the following vigorous protest--and certainly
+such men as he are in the best position to know. He says: "No one doubts
+for a moment that defective mental conditions are transmitted from parent
+to child as surely as the physical defects and deformities. Every one
+knows that it is common for defectives to be attracted to each other and
+marry, and that the defects of both parents are liable to be transmitted
+to the children. It is also true that there are more children born in such
+families; and for that reason the percentage of defectives is continually
+on the increase. The report of the state of Illinois shows the increase to
+be alarming, and many other states are no better. It is absolutely wicked
+that the persons suffering from periodical insanity should be allowed to
+return to their homes to propagate and scatter their children about the
+state as dependents."
+
+=Examples of Hereditary Feeble-Mindedness.--=No one can look at the
+remarkable series of charts and records brought together by Doctor Goddard
+of the institution at Vineland, New Jersey, and by other directors of
+similar institutions, and doubt for an instant the inheritability of
+feeble-mindedness and allied defects. In some instances the family history
+has been followed back as far as five generations, and it is always the
+same dire sequence of insanity, idiocy, epilepsy or feeble-mindedness,
+from generation to generation. For example, Fig. 33, p. 236, is one of
+Doctor Goddard's charts. It shows thirteen descendants of a supposedly
+normal father (possibly a carrier) and a feeble-minded mother, of whom
+seven were feeble-minded, the others dying in infancy. The mother herself
+was one of seven feeble-minded children, who were in turn the descendants
+of feeble-minded parents, of whom the woman had five feeble-minded
+brothers and sisters. In Fig. 34, p. 237, he shows mental defects running
+through four generations. Fig. 35, p. 238, is a remarkable exhibit which,
+starting in the fifth generation back with a feeble-minded, alcoholic
+man--the mental condition of his wife being unknown--shows that in every
+generation down to and including the present there has been nothing but
+feeble-minded (or worse) offspring, leaving out of account two unknown
+and a number who died in infancy without revealing their mental condition.
+This is true notwithstanding the fact that in the course of the various
+generations there had been several matings with apparently normal
+individuals. The new blood, however, instead of redeeming the tainted
+stock, itself became vitiated. The numerous specific cases of inheritance
+of family traits reviewed in recent books or in special reports of trained
+workers give us abundant confirmatory evidence of the inevitable
+inheritance of various nervous and mental defects.
+
+
+[Illustration: FIG. 33
+
+Inheritance of feeble-mindedness (after Goddard): squares represent males,
+circles females; F, feeble-minded; N, normal; E, epileptic; I, insane; C,
+criminal; T, tuberculous; d. inf., died in infancy; the hand shows the
+individual from whom the record was traced back; small black circle
+indicates miscarriage.]
+
+
+=Difficult to Secure Accurate Data.--=It is obvious, of course, that in
+tabulations such as these there may lurk considerable margins of error.
+Notwithstanding our Binet-Simon and other tests for feeble-mindedness, for
+example, there is yet much to be desired in the way of accuracy. Many
+cases just bordering normality are by no means easy to decide. Then again
+in most human records, when one gets back beyond the third or, at most,
+the fourth generation, the investigator has to depend on the hearsay
+evidence of relatives, friends or neighbors, and how vague this generally
+is can only be appreciated by those who have themselves tried to collect
+such data. But in spite of all the difficulties, there is little doubt
+that the more carefully prepared records are sufficiently accurate to
+establish the fact beyond dispute that defective tends in large measure to
+breed defective.
+
+
+[Illustration: FIG. 34
+
+Inheritance of feeble-mindedness (after Goddard); symbols same as in Fig.
+33, p. 236.]
+
+
+One serious drawback in making a study of the inheritability of insanity
+and other nervous disorders is that so far we have dealt mainly with mass
+effects rather than specific neuroses. But even when the latter is
+attempted we are confronted by the fact that there are various
+intergradations of the recognized types of defect, that because of
+varying degrees of defect in the same type a standard is hard to
+establish, and above all that what appears as a specific mental malady in
+one individual may crop out in his descendants in an entirely different
+guise. Moreover, not only the predisposition of the individual, but age
+and precipitative cause enter as factors in determining the ultimate
+symptoms.
+
+
+[Illustration: FIG. 35
+
+Inheritance of feeble-mindedness (after Goddard); symbols same as in Fig.
+33, p. 236.]
+
+
+=Feeble-Mindedness and Insanity Not the Same.--=Authorities make a sharp
+distinction between insanities on the one hand and feeble-mindedness on
+the other. According to Goddard, not only is there no close relationship
+between the two conditions, but in reality they stand at opposite ends of
+the psychical scale. In general, insanity is a degenerative process,
+whereas feeble-mindedness is an arrest of development. In the first case
+the victim loses part of the mentality he once had, in the second he stops
+short of normal development.
+
+=Many Types of Insanity.--=The commonest manifestations of insanity are
+undue depression, apathy, excitement, instability, obsessions,
+hallucinations and delusions. Some mental disorders are associated with
+recognizable structural changes in the nervous system, but the structural
+basis of many is not known.
+
+In general there is more doubt about the inheritability of some of the
+insanities than about cases of mental deficiency. The term insanity is
+merely a loose descriptive one, and we shall gain little definite
+knowledge about the inheritance of such maladies until we study each
+separate insane diathesis specifically. Psychiatrists recognize many
+different forms of insanity, some of them very distinct from others and
+the product of unrelated underlying causes. Often it is only a question of
+degree or sometimes a matter of chance as to whether a given individual is
+certified as insane or not. A neuropathic person who manifests certain
+anti-social activities is sure to be classed as insane, whereas another
+individual with the same diathesis in a less degree might pass
+unrecognized. It is almost impossible in some instances to tell just where
+the border-line between a neuropathic and a normal constitution lies. Many
+of the idiosyncrasies of the insane, indeed, are merely exaggerations of
+characteristics seen in normal people. Recent studies of the psychology of
+the insane show that most of their hallucinations and delusions are
+closely related to some previous mental experience they had before
+becoming insane. And it has been found that the surest means toward
+removing the obsessions of the patient in curable cases is to ferret out
+these earlier experiences and correct the wrong impressions regarding
+them. Again, certain forms of insanity do not become manifest except as
+special reactions to particular environmental conditions, and if these
+conditions do not happen to occur, then the neuropathic constitution
+though existing would not be revealed. Certain critical periods of life
+such as puberty, pregnancy and the close of sexual life are particularly
+likely to test out the mentally unstable, although such individuals may
+have maintained normal mental balance up to the crisis in question.
+
+=Not All Insanities of the Same Eugenical Significance.--=Of the various
+kinds of insanity some seem to be of much greater eugenical significance
+than others, not only because they are strongly heritable, but also
+because of the periodicity of the attacks. The patient may be repeatedly
+in and out of the asylum and in his sane intervals wholly unrestrained as
+far as propagating his kind is concerned. _Manic depressive_ psychoses and
+_dementia precox_ in the order named represented the largest number of
+admissions to the Wisconsin State Hospital for the Insane in 1911 and
+1912, and both of these very frequently have a hereditary basis. Fig. 36,
+a chart showing the insanity in a local family as worked out by one of my
+pupils, is a good example of a recurrent type. The father (Fig. 36, p.
+241) was about eighty-two years old when the record was made. His memory
+was poor and he could not talk connectedly, although this was possibly
+attributable to old age rather than to insanity. His brother, written to
+in Ireland, stated that to his knowledge there had never been insanity in
+his side of the family. The mother (2) was insane at nine, again at
+twenty-nine and again at thirty-six. In her later life she has been in the
+Mendota Hospital for the Insane five times and in the County Asylum twice.
+The eldest daughter (3) has been in the State Asylum five times and is now
+at home. The next daughter (4) spent five months in the asylum in 1885.
+Another daughter (5) likewise spent a short period in the asylum. Two sons
+(6, 7) have each spent two periods in the asylum, and a third son (8) has
+had an attack of insanity. The youngest child died at the age of three.
+Thus of the eight adult children six have been insane at some time. The
+cases in this family seem all to be instances of manic-depressive
+insanity.
+
+
+[Illustration: FIG. 36
+
+Inheritance of insanity in the L---- family. See text for description.]
+
+
+=A Neuropathic Constitution May Express Itself Differently Under Different
+Conditions.--=Some of the difficulties of getting genealogies of specific
+forms of insanity are obvious from the following quotations chosen from
+the works of eminent psychiatrists. Kraepelin, for instance, expresses the
+opinion that: "The psychopathic charge of a family may reveal itself not
+only by the appearance of mental disorders but also by other forms of
+manifestation. Here belong before all, those diverse slighter deviations
+from mental health which go to make up the borderland of insanity:
+nervousness, states of anxiety and compulsion, constitutional depressions,
+slight hysterical disorders and forms of feeble-mindedness, tics; also odd
+characters, peculiarities in mode of living, criminal tendencies, lack of
+self-control, intemperance, love of adventure, mendacity, suicide on an
+inner basis."
+
+From the volume of Church and Peterson on _Nervous and Mental Diseases_ a
+further confirmatory opinion may be cited: "In determining the factor of
+heredity we must not be content with ascertaining the existence of
+psychoses in the ascendants, but must seek, by careful interrogation of
+various members of the family, for some of the hereditary equivalents,
+such as epilepsy, chorea, hysteria, neurasthenia, somnambulism, migraine,
+organic diseases of the central nervous system, criminal tendencies,
+eccentricities of character, drunkenness, etc., for these equivalents are
+interchangeable from one generation to another, and are simply evidence of
+instability of the nervous system. It is the unstable nervous organization
+that is inherited, not a particular neurosis or psychosis, and it must be
+our aim in the investigation of the progenitors to discover the evidence
+of this."
+
+=Certain Forms of Insanity, But Not All, Seem to Behave as Mendelian
+Recessives.--=A number of psychiatrists and investigators of the
+inheritance of insanities (Rudin, Lunborg, Davenport, Rosanoff, Jolly),
+although working independently and in different countries, concur in the
+opinion that manic-depressive insanity, dementia precox and allied
+psychopathic conditions tend to occur after the manner of a Mendelian
+recessive. On the other hand such maladies as Huntington's chorea are
+transmitted as a dominant and in all probability at least half of the
+children of an afflicted individual will inherit and manifest the defect.
+As to inheritance of various other psychoses we have too few accurately
+charted pedigrees for most types to make very positive statements about
+their degree or manner of inheritance. Little can be said beyond the
+statement that there is a decided tendency for various forms to recur in
+offspring. Where more than one case of insanity occurs in a given family
+or stock it is strong presumptive evidence that a hereditary defect is at
+the bottom of it. As Doctor Wilmarth says, "Mental accident may occur in
+any family, but it is rarely a second case occurs unless there is a
+tendency to nerve degeneracy." For example, of 818 insane at the Wisconsin
+State Hospital for the Insane during the biennium 1909-10, 187, or
+practically one-fourth were positively known to have insane relatives. Of
+these, 24 had insane fathers, 31 insane mothers, 30 insane brothers, 23
+insane sisters, 25 insane uncles, 21 insane aunts, and 21 insane cousins.
+Where definite information could be obtained it was found that of the
+5,700 admissions of insane patients to the New York state hospitals
+during the year ending September 30, 1911, 27.7 per cent. of the cases
+showed a history of insanity in the family and an additional 22.9 per
+cent. showed a history of alcoholism, nervous diseases and the like.
+
+=Grades of Feeble-Mindedness.--=As to the various grades of
+feeble-mindedness, while no sharp lines of demarcation can be drawn, a
+rough and ready test usually applied is the relative ability of such
+subnormal individuals to take care of themselves. In all, the conditions
+exist from birth or shortly after. _Idiots_ are such defective individuals
+as are unable to take care of themselves even to the matter of guarding
+against common physical dangers. Their mentality does not progress beyond
+that of a two-year-old child. _Imbeciles_ can take care of themselves in
+the cruder physical ways, but are unable to earn their living. Their
+mental age ranges from three to seven years inclusive. _Morons_, or the
+"feeble-minded" in a more specific usage of the term, can under proper
+direction become more or less self-supporting but they are as a rule
+incapable of undertaking affairs which demand judgment or involve
+unrestricted competition with normal individuals. Their intelligence
+ranges with that of normal children from seven to twelve years of age. The
+last class grades up insensibly into the shiftless, ne'er-do-well types
+which exist in every community. It is the hordes of the feeble-minded in
+the restricted sense that afford our most serious problems to-day. The
+idiot and the imbecile are usually early and easily recognized and are
+kept more or less under restraint, but the higher grades of feeble-minded,
+the so-called moron type, can be detected often only by carefully devised
+tests.
+
+=About Two-Thirds of the Feeble-Minded Have Inherited Their
+Condition.--=Concerning the various types of feeble-mindedness there is
+strong evidence that heredity is a factor of greater magnitude than in
+most insanities. All facts point to the conclusion that most mental
+deficiency is strongly inheritable and that the majority of our defectives
+of this type come from degenerate stocks. Practically all specialists at
+the heads of asylums and homes for the mentally deficient concur in the
+opinion that about two-thirds of the cases are hereditary. For example,
+Doctor Alfred Wilmarth, superintendent of the Wisconsin Home for
+Feeble-minded, says: "My own observations, and those of others in this
+country and Europe, would indicate that at least two-thirds of the
+feeble-minded have defective relatives."
+
+In his study of two thousand children tested by the Binet measuring scale
+for intelligence, Doctor Henry H. Goddard, director of the Department of
+Research at the Training School for Feeble-minded at Vineland, N. J.,
+remarks concerning heredity of feeble-mindedness: "But we now know that
+sixty-five per cent. of these children have inherited the condition, and
+that if they grow up and marry they will transmit the same condition to
+their offspring. Indeed, we know that this class of people is increasing
+at an enormous rate in every community and unless we do something to stop
+this great stream of bad protoplasm we shall some day be swamped in a sea
+of degeneracy."
+
+E. R. Johnstone, superintendent of the training school at Vineland, N.
+J., in a recent bulletin remarks concerning feeble-minded and epileptics,
+"We are now convinced that from sixty to eighty per cent. of the cases are
+hereditary."
+
+Again, we find Doctor A. C. Rogers, superintendent of a school for
+feeble-minded in Minnesota, saying, "We have no survey of mentality in
+this country except in very small areas, but probably about sixty-five per
+cent. of the feeble-minded children that we know of are feeble-minded from
+heredity; that is, they come from families in which there is much
+feeble-mindedness, usually associated with various neuroses or psychosis.
+There are about thirty-five per cent. approximately that are acquired
+cases. These cases develop from various things. Full development may be
+prevented during gestation, or early childhood, or early adolescence, but
+these acquired cases are entirely distinct from the hereditary ones."
+
+In a recent paper Doctor Martin W. Barr, chief physician for the
+Pennsylvania Training School for Feeble-minded Children, says: "In my
+individual study of 4,050 cases of imbecility, I find 2,651, or 65.34 per
+cent., caused by malign heredities; and of these 1,030, or 25.43 per
+cent., are due to direct inheritance of idiocy; and 280, or 6.91 per
+cent., to insanity." From these figures it will be seen that Doctors Barr,
+Goddard, Wilmarth, Johnstone and Rogers all agree in their estimates;
+namely, that two-thirds of our imbeciles are so through inheritance.
+
+=Some Results of Non-Restraint of the Feeble-minded.--=The following
+excerpt from a paper by Doctor Barr, is a fair sample of what happens
+when such defective individuals are not restrained from propagating their
+kind:
+
+    "My own study and observation alone, of over 4,000 degenerates, shows
+    such examples as: A man 38 years of age, the father of 19 defective
+    children, all living, he and his wife both under par mentally; as was
+    another couple, with 9 imbecile children; an idiot woman with 7 idiot
+    children. A forcible instance is that of a man with two daughters and
+    one illegitimate grandchild, all feeble-minded.... I could name a
+    family, one of the proudest in the land, where there are five
+    children, an aunt and two uncles, all feeble-minded.
+
+    "Yet another, which in seven generations numbering some 138
+    individuals, records 10 still-born children (premature births), 16
+    insane, 7 imbeciles, 3 epileptics and 32 with mental peculiarities so
+    pronounced as to occasion remark. Of the 138 there remain 80
+    apparently normal, who are nevertheless hopeless slaves of a neurotic
+    heredity, direct or collateral.
+
+    "In a study of 15 imbecile girls, 3 were recognized prostitutes, 9 had
+    each 1 illegitimate child (2 being the result of incestuous
+    intercourse with brothers); 1 had 2; 2 epileptics had, the one 3, and
+    the other 4 idiot children.
+
+    "Four feeble-minded women had 40 illegitimate children.
+
+    "A feeble-minded woman living in an almshouse since early childhood,
+    allowed to go out to service periodically, had given birth to six
+    illegitimate children, all inheriting her defect.
+
+    "An imbecile drunkard is the father of three feeble-minded children.
+    The daughter, seduced before the age of sixteen, gave birth to an
+    idiot child; one son is a harmless imbecile, but the other is a moral
+    imbecile, a sexual pervert, a thief on the streets, and a pyromaniac,
+    firing in sheer wantonness a large mill property.
+
+    "Another shows the entire family for three generations below normal.
+    Father, mother, mother's sister, and father's uncle, all imbecile.
+    Five children feeble-minded. One girl had a proposal of marriage, and
+    one boy is married to a feeble-minded girl.
+
+    "One insane woman, whose brother and sister committed suicide, had
+    five sons. The oldest, feeble-minded, a drunkard and hobo, had one
+    son, a criminal. The second son, insane, had three imbecile children.
+    The third, an insane epileptic, had three imbecile sons, one of whom
+    was an epileptic. The fourth son was insane. The fifth, apparently
+    normal, had a morally imbecile son and an epileptic daughter."
+
+Yet striking as is the inheritance of these maladies, Doctor Barr points
+out that of the 10,000 known cases of feeble-mindedness in Pennsylvania,
+only 3,500 are sequestrated. This leaves a balance in that state of 6,500
+totally irresponsible individuals to work havoc in society by producing
+their kind.
+
+=Inheritance Not a Factor in Some Cases of Mental Deficiency.--=On the
+other hand as our data show, there remain about one-third of the mentally
+deficient type to be accounted for on other than a basis of heredity. As
+already noted, some of these are doubtless the product of suppressions of
+normal development by various extraneous factors operating before or
+shortly after birth. There is one class particularly, estimated by some
+authorities as constituting as high as thirty per cent. of the
+feeble-minded which is unusually puzzling. These are the so-called
+mongolians. The name is given because the features of such individuals
+bear more or less resemblance to those of some of the Mongolian races. The
+defect does not seem to be hereditary although it is usually congenital.
+It appears to be due to something which interferes with prenatal
+development. Whatever the conditions, whether lack of nutrition in the
+mother, alcoholic or other poisoning, the cases seem to be as hopelessly
+incurable as are the hereditary forms. From the social standpoint, of
+course, such individuals are in their immediate generation, as incompetent
+or as dangerous to society as those suffering from the more surely known
+hereditary forms of mental defect.
+
+=Epileptics.--=Although epileptics are not classed as imbeciles
+ordinarily, as a matter of fact no sharp distinction can be drawn between
+the two classes. Doctor Wilmarth says, "Epilepsy and mental deficiency are
+as closely related as branches on the same tree.... Over one-half and
+perhaps two-thirds of all feeble-minded are subject to convulsive seizures
+at some period of their lives, and we are never surprised at the
+appearance of epilepsy in any feeble-minded person. On the other hand, so
+small a percentage of epileptics maintain normal mental actions as hardly
+to be worth consideration ... even those who retain a normal mind in the
+early stages of the diseases almost infallibly become imperfect later."
+How slight a chance the epileptic has of ever becoming normal may be
+inferred from a statement made by Doctor Frank Billings in a paper read
+before the Illinois State Medical Society in 1909 to the effect that "ten
+per cent. or more can be cured by proper care."
+
+According to the estimates of "The Committee of Fifty" in the state of
+Illinois, who have been agitating for the establishment of a colony for
+epileptics, there are 10,000 of these unfortunates in that state. The
+consensus of opinion of experienced workers in various states is that
+there is about one epileptic to each three hundred fifty to five hundred
+inhabitants.
+
+=In Heredity Conditions of Feeble-Mindedness Are Probably Recessive to
+Normal Condition.--=As to the mode of inheritance of the various forms of
+feeble-mindedness, the evidence points to such defects in the main as
+being recessive. However, no particular grade can be picked out and shown
+to be a pure recessive. For instance, the children of two epileptics will
+be defective but it is impossible to predict always whether the defect
+will appear as epilepsy or feeble-mindedness. This is doubtless due to the
+fact that mental deficiencies even of the inheritable type are not all due
+to the same specific cause, and in many cases the individual is defective
+in more than one direction. If one or more of a great number of units
+which are necessary for complete mental development are lacking, obviously
+mental deficiency will result. In other words, feeble-mindedness and
+allied disorders may not be definite characters, but simply evidences of
+the fact that the nervous system has not developed all factors necessary
+for normal mental coordination. Goddard, however, one of our best
+authorities on the heredity of feeble-mindedness, is inclined to regard
+the condition as a unit character, "due either to the presence of
+something which acts as an inhibitor, or due to the absence of some
+stimulus which sends the normal brain on to further development."
+
+Supposing nervous defects finding expression in feeble-mindedness,
+epilepsy and related conditions, to act as a Mendelian recessive, then the
+marriage of one such defective with another should yield only mentally
+enfeebled offspring. How nearly this expectation may be realized is seen
+from the following examples.
+
+In an extensive study[9] of feeble-mindedness, just from the press, Doctor
+Henry H. Goddard points out that of 482 children with both parents
+feeble-minded all but six were feeble-minded. Even the exceptions may be
+apparent rather than real as there is possibility of mistake in judging
+the condition of the parents or of the children themselves. Moreover, with
+the feeble-minded one is not always sure of the paternity of a child, as
+is instanced by Doctor Goddard in a case quoted from Doctor Emerick in
+which of twelve children in a white family with both father and mother
+feeble-minded ten were feeble-minded and two were not, but these two were
+_mulatto_ children.
+
+In a paper by Weeks (_The Inheritance of Epilepsy_), in part an extension
+of an earlier joint paper by Davenport and Weeks, is recorded among others
+a study of twenty-seven fraternities in which both parents were either
+epileptic or feeble-minded. Of the 28 progeny, 19 lived long enough to
+reveal their mental state. Of these 3 were feeble-minded, 8 epileptic and
+8, from parents who developed epilepsy late in life, were what Doctor
+Weeks terms "tainted." In 15 fraternities in which one parent was
+epileptic and the other feeble-minded he found there had been 81
+conceptions. Of these 7 were too young to classify and 19 had died before
+fourteen years of age. Of the remaining 55, 28 were epileptic, 26
+feeble-minded, and 1 insane. Again, in 9 families in which the parents
+were both feeble-minded, of the 38 surviving offspring who were old enough
+to classify, 7 were epileptic, 29 feeble-minded, and 2 drunkards. In 5
+families where one parent was insane and the other epileptic or
+feeble-minded, 5 children died before the age of fourteen, the condition
+of 2 was unknown, 2 were epileptic, 4 feeble-minded, 1 insane, 8 tainted,
+and 7 seemingly normal. Regarding the latter Doctor Weeks says they came
+from two families where in one case the father's insanity seemed to be
+traumatic and in the other alcoholic.
+
+In a few cases where the defect in one parent has apparently been of a
+type different from the defect of the other parent a "normal" child was
+produced. That is, presumably each parent carried normality in the trait
+defective in the other so that the child became simplex with reference to
+each defect. Davenport points out that not infrequently two deaf-mutes
+whose defects are due to different causes may have normal children.
+
+In general, however, the reasonable expectation is that where two
+feeble-minded individuals marry, a very common occurrence, the children
+will all show mental deficiency. A mating between a feeble-minded person
+and one of perfectly normal stock will apparently result in normal
+children although they will be carriers. There is some evidence, however,
+that such carriers may occasionally show "taints" of abnormality in the
+form of migraine (nervous sick headache), alcoholism, queerness, violent
+temper, etc. Thus according to the studies of Doctor Weeks, "In 50 matings
+where at least one parent is migrainous, there were 350 conceptions, of
+which number enough is known of 212 to classify 55, or 26 per cent., as
+epileptic; 12, or 6 per cent., as feeble-minded, with the others tainted
+or normal. In the 131 matings where at least one parent is alcoholic,
+there were 845 conceptions. Of the 494 classified, 151, or 31 per cent.,
+were epileptic; 54, or 11 per cent., feeble-minded, with the balance
+tainted or normal." Marriage between two carriers will cause the defect to
+reappear in active form in approximately 25 per cent. of the offspring and
+50 per cent. will continue to be carriers.
+
+=Many Apparently Normal People Really Carriers of Neuropathic
+Defects.--=There is considerable evidence that many apparently normal
+individuals of our average population are in reality carriers of some form
+of neuropathic defect, some authorities placing the proportion
+provisionally at over thirty per cent. This being true, then it is easy to
+explain the apparently unaccountable appearance of epilepsy,
+feeble-mindedness, or similar defects among the children of what pass for
+normal stocks. The probabilities are that in many cases it means simply
+that the parents of the defective children have been carriers.
+
+As to the contention that in preventing the propagation of the
+feeble-minded we may be depriving the world of geniuses, Doctor Goddard
+remarks: "It is a significant fact that in our three hundred family
+histories totaling 11,389 individuals not a single genius has been found.
+Not only are there no geniuses but the fact can not be too strongly
+emphasized that even the people who are considered normal ... are not as a
+rule people of average intelligence...." However, between insanity and
+genius he finds more kindred spirit.
+
+=Tests for Mental Deficiency.--=As to tests for mental deficiency, the one
+commonly meted out to victims in the every-day world is the
+social-economic one of survival in the competitions of life. The mentally
+deficient fail. Although often unrecognized as feeble-minded they drift
+through life social and economical derelicts who have to be supported by
+the community.
+
+Of laboratory tests many have been devised. While all yet leave much to be
+desired, still through their application the majority of mental defectives
+can be detected. Fairly accurate standards of normality have been
+established from which the relative degree of "backwardness" can be
+determined. We have just awakened to the importance of detecting
+defectives early in life, hence many of our tests have been planned with
+reference to children. They are based not so much on training or conscious
+learning as on fundamental processes which develop at certain ages in
+children. Another impetus toward securing adequate criteria of mental
+deficiency has been the crying need of having some easily applied standard
+for detecting the very large numbers of defective immigrants who are
+continually seeking to enter the United States.
+
+Most of the methods consist of "performance" tests which are planned to
+test the powers of perception, concentration, application, ingenuity and
+education of the subject. Previous environment, education and the
+difficulties under which the subject may be laboring at the time of the
+test must, of course, be taken into account. It is particularly difficult
+to get adequate tests for the immigrant which will enable one to
+distinguish between ignorance, stupidity, fear and temporary psychic
+depression on the one hand, and congenital mental deficiency on the other.
+
+Perhaps the most successful single set of tests for mental deficiency is
+that known as the Binet-Simon Scale. From an examination of large numbers
+of French school children Binet constructed a scale of tests of increasing
+complexity accurately graded to age and previous training of the average
+normal child. In the Binet-Simon system tests are given for each age from
+three years to thirteen. When a child successfully passes the tests for
+his age he is classed as normal. If he succeeds only in tests which
+normally are those given for a child a year younger then he is backward to
+the extent of one year. Similarly he may show by these graded tests that
+he is backward to the extent of two years, three years and so on. If a
+child is more than three years backward according to the test he is
+regarded as mentally defective. Various corrections and adjustments of the
+original scale have been worked out to allow for unevenness in mental
+development. On the whole the scheme works out satisfactorily when applied
+by one skilled in its use. The attitude of the examiner, however, is of so
+great importance that the tests are of less value in the hand of
+inexperienced workers. A revision of the scale to adapt it better to
+American children has recently been made by Doctor Goddard.[10] Besides
+the Binet-Simon tests various performance tests, standardized for children
+of different ages, such as Seguin's form board, Healy's pictorial
+completion test, Fernald's construction puzzle, the Rossolimo test, De
+Sanctis test, etc., are used by different investigators. Questions
+designed to reveal moral tone are also employed. Doctor Howard A. Knox,
+assistant surgeon United States Public Health Service, in a recent
+article[11] gives an interesting account of the tests applied to determine
+the exact mentality of immigrants entering the United States together with
+a brief review of various tests. A full account and discussion of the
+various tests for the mentally subnormal will be found in a recent
+publication by Doctor William Healy,[12] director of the Juvenile
+Psychopathic Institute, Chicago.
+
+=The Backward Child in School.--=It is only in recent times that we have
+come to realize the seriousness of the problem which the backward child
+presents in our schools. It is of the utmost importance to discover early
+in school life which of the backward children owe their condition to
+adenoids, defective sight or hearing, poor nutrition, imperfect
+circulation, or other remediable defects, and which are the victims of
+innate mental deficiency. The treatment of the individual must be very
+different in the two cases. In the one the condition can be cured by
+proper manipulations or other treatments; in the other it can only be
+ameliorated. All school children who are two or three years below grade
+should be rigidly inspected by the medical examiner.
+
+From a study of about two thousand children comprising the first five
+grades of an entire public school system Goddard found that eighteen per
+cent. were definitely "backward." Of these between two and three per cent.
+were actually feeble-minded, the condition in the remaining fifteen per
+cent. being presumably capable of correction. Other similar surveys have
+given practically the same results.
+
+=The Exceptionally Able Child Likely to Be Neglected.--=However, while we
+must not forget that it is important to recognize backward children and to
+see that they are segregated into small groups which are not required to
+do the full amount of work in regular time, it is equally urgent to see
+that the unusually bright individual is also given opportunity to advance
+more rapidly than the rank and file. Only too often the holding back of a
+child in school leads to lack of interest and habits of mental laziness,
+and sometimes to truancy and incorrigibility. The general attempt in our
+graded schools to keep all children close to the average is to be strongly
+condemned.
+
+=Cost of Caring for Our Mentally Disordered.--=Doctor Charles L. Dana,
+member of the National Committee for Mental Hygiene, estimated in 1904
+that the actual cost of caring for feeble-minded and insane in the
+United States amounted to sixty million dollars, to which should be added
+the corresponding loss in industrial activity on the part of the
+afflicted,--at least twenty million dollars more, and he figures that the
+amount was increasing at the rate of four per cent. per annum. Many
+investigators concur in the opinion that our insane and feeble-minded
+alone cost us far above one hundred million dollars. Adding to this
+economic burden the cost of our delinquents and criminals the total
+expense becomes stupendous. And when we consider still further the even
+greater burden of suffering of the unfortunates themselves and the sorrows
+of those to whom they are dear, a burden not measurable in money, the
+feeling that something must be done to relieve the situation becomes
+overpowering.
+
+=Importance of Rigid Segregation of Feeble-Minded.--=As regards the really
+feeble-minded little can be done beyond making them as happy as possible
+and developing the limited gifts they have been given by nature. Their
+teaching must be in the main concrete and simple. At the age of puberty it
+is imperative to see that the sexes are separated and kept under
+sufficient permanent supervision to prevent all possibility of
+procreation. There is neither economic nor common sense in even allowing
+the remotest chance of such occurrences as the following: "This is the
+case of a feeble-minded and epileptic woman who had six children by
+various persons while an inmate of a county poor house. One child at the
+age of eighteen died in the almshouse, two died in infancy, one was
+epileptic (the son of a man with a criminal record) and two who are now
+living in the almshouse are feeble-minded, one being the son of a negro."
+Again, we find a superintendent of an English almshouse reporting that one
+hundred and two out of one hundred and five children born there in five
+years were feeble-minded.
+
+As conditions are to-day every institution for the feeble-minded has a
+long waiting list and the same is true of most asylums for the insane.
+Instead of providing the prolonged care necessary for such patients,
+institutions are forced to discharge many prematurely in order to make
+room for more urgent cases.
+
+=Importance of Early Diagnosis of Insanity.--=In insanities, even when of
+hereditary origin, there is much hope in certain cases of greatly
+benefiting the individual, though a permanent cure, or at least the
+establishment of procreative fitness may be impossible. It is extremely
+important that the public realize how much can be done through early
+examination and advice in such mental afflictions. Most of the insane who
+recover usually do so within a few months of their first alienation, hence
+the importance of losing no time in detecting the condition and securing
+early treatment. It is now well known that many cases of chronic insanity
+may be measurably improved under the care of a psychiatrist by systematic
+re-education, especially in industrial lines. But how little of this may
+be expected at the hands of the untrained custodians who "feed" the
+inmates of our county almshouses, to which in many states the chronic
+insane are entrusted, is obvious.
+
+=All Insane Should Be Passed Upon by Competent Psychiatrists.--=The
+atrocious system of turning the chronic insane over to county poorhouses
+manned by supervisors whose chief qualification for the position has not
+infrequently been the lowness of their bid for boarding and caring for the
+inmates, can not be too strongly condemned. Incredible as it may seem, in
+some states the court can on its own judgment send patients directly to
+these institutions without first submitting them to the study of expert
+physicians in the state hospital for the insane. The viciousness of such
+procedure is evident when one realizes that often careful scrutiny on the
+part of the very best experts, extending over a considerable period of
+time, is required before the true condition of the patient can be
+determined. Recently a psychiatrist of high standing, who was gathering
+data on county asylums for a national organization, informed the writer
+that beyond the shadow of a doubt he had come across case after case in
+county asylums which would have been curable under proper treatment.
+
+Here again the responsibility in last analysis must rest upon us as
+citizens, for it is largely through our intelligent demands as voters that
+conditions will be improved and competent experts be put in charge of
+county asylums as well as of the state hospitals for the acutely insane.
+
+=Some Insanities Not of Hereditary Origin.--=Some alienists believe that
+self-poisoning known as _auto-intoxication_, due to improper elimination
+of poisons generated through faulty digestion or metabolism, if of long
+standing, may be not only a contributory but a more or less direct cause
+of insanity. About twenty per cent. of insanities of men living in cities
+and about fifteen per cent. of those living in the country seem to be
+directly related to the intemperate use of alcohol. The corresponding
+figures for women are seven per cent. and one per cent. respectively.
+General paresis or softening of the brain is probably invariably preceded
+by syphilis. About twenty-two and five-tenths per cent. of the first
+admissions to hospitals for the insane from city-dwelling men, and eight
+per cent. from men living in the country in the state of New York are
+cases of this kind of insanity. The corresponding figures for women are
+five and five-tenths per cent. and two and five-tenths per cent.
+respectively.
+
+=Importance of Heredity in Insanity Not Appreciated.--=We have already
+seen that heredity plays an important part in insanities. There can be
+little doubt that the tendency is to under-estimate rather than
+over-estimate its importance. Many cases said to be "caused" by mental
+strain such as those occasioned by domestic infelicities, business
+reverses and the like should in all probability be fundamentally
+attributed to something far more deep-seated than the more obvious cause.
+In many such instances there is little doubt that an inherent weakness in
+mental make-up exists which predisposes the individual toward mental
+breakdown. This is more apparent when one recalls that there are thousands
+of other individuals who undergo equally great or greater calamities
+without loss of mental balance. There are well-recognized types of mental
+disposition which later contribute to corresponding forms of insanity. In
+many instances the final catastrophe may be averted if the "peculiar"
+individual can be kept in good health and guided into right habits of
+thought. Undoubtedly certain infectious diseases, arterio sclerosis,
+various poisons in the blood, child-birth, and similar influences often
+enter as important contributory factors. In all cases of cure, however, we
+must face the fact that under existing conditions these mentally restored
+individuals are released into society without let or hindrance as regards
+their marital relations.
+
+
+
+
+CHAPTER IX
+
+CRIME AND DELINQUENCY
+
+
+=The Relative Importance of Heredity and Environment in This Field
+Uncertain.--=The whole question of crime and delinquency is a highly
+complex one. Here, perhaps, more than in any other phase of race
+betterment we find the greatest difficulty in separating the effects of
+hereditary predisposition from the results of unfavorable environment.
+While there is no longer a reasonable doubt about such nervous disorders
+as epilepsy, feeble-mindedness and certain forms of insanity being rooted
+largely in ancestral taints, the degree to which crime or delinquency is
+based on heredity is far more questionable. Every student of genetics
+knows that we may have dwarf plants because the constitution of the germ
+is of a nature to produce only such individuals, or we may have dwarfed
+plants because of adverse conditions of soil and lack of an opportunity to
+climb or rise to their full capacity. Bateson pertinently remarks, "The
+stick will not make the dwarf pea climb, though without it the tall can
+never rise. Education, sanitation, and the rest are but the giving or
+withholding of opportunity." The important sociological question for us to
+determine is which of these lowly peas of the human family are really
+dwarfs and which are dwarfed simply because the stick of opportunity on
+which to climb is lacking.
+
+Beyond doubt a considerable portion of crime and degeneracy is due in
+large measure to innate inclination, but with just as little doubt much is
+the effect mainly of vicious habits acquired through an unwholesome
+environment. A normal appetite or impulse may be given a pathological
+trend by bad influences. And one has to reckon, moreover, with degrees of
+hereditary aptitude to crime. Just what is the measure of normality? To
+what extent by developing to their highest point certain inhibitive or
+opposing tendencies, can we counteract certain inherent proclivities for
+wrong-doing? By what means shall we sift the congenital defectives from
+the victims of suppressed opportunities? These and kindred questions
+confront us at the very outset of our studies of crime and delinquency. It
+is obvious that although we may institute the strictest elimination of the
+socially unfit, unless we can provide a wholesome environment for the fit,
+lapses into unfitness are sure to recur.
+
+=Feeble-Mindedness Often a Factor.--=The conviction is steadily growing
+among students of human heredity that a considerable amount of crime,
+gross immorality and degeneracy is due at bottom to feeble-mindedness and
+that, therefore, if we can once eliminate feeble-mindedness, these vicious
+accompaniments will at the same time in equal measure disappear. Goddard,
+for example, one of our authorities on the inheritance of
+feeble-mindedness, is convinced that a large proportion of the delinquent
+girls who fill our reformatories are actually feeble-minded. They are
+often the higher grade or moron type, and their mental condition remains
+unsuspected because they have never been thoroughly tested in this
+respect.
+
+=Many Delinquent Girls Mentally Deficient.--=According to Havelock Ellis,
+2,500 of some 15,000 women who passed through Magdalen homes in England
+were definitely feeble-minded and were known to have added a thousand
+illegitimate children to the population.
+
+The preliminary reports of the so-called white slave investigations now in
+progress in New York City classes 25 per cent. of these unfortunate women
+as mentally incapable of taking care of themselves. Other investigations
+indicate that from 40 to 60 per cent. of this class of women are
+defectives. For example, from the report of the Massachusetts "Commission
+for the Investigation of the White Slave Traffic, So-Called," one reads:
+"Of 300 prostitutes, 154, or 51 per cent., were feeble-minded. All
+doubtful cases were recorded as normal. The mental defect of these 154
+women was so pronounced and evident as to warrant the legal commitment of
+each one as a feeble-minded person or as a defective delinquent.... The
+135 women designated as normal, as a class were of distinctly inferior
+intelligence. More time for study of these women, more complete histories
+of their life in the community, and opportunity for more elaborate
+psychological tests might verify the belief of the examiners that many of
+them were also feeble-minded or insane."
+
+The data from some of our public reformatories, industrial schools and
+state homes for delinquent girls, are very instructive in this respect.
+Reports from a number of such institutions show that many of their inmates
+are mentally subnormal. The proportions range from thirty-three per cent.
+in the New Jersey Reformatory at Rahway to eighty-nine per cent. in the
+institution at Geneva, Illinois.
+
+=Institutional Figures Misleading.--=However, significant as are these
+figures from institutions for delinquents, one should not be misled by
+them. They are undoubtedly not representative of offenders in general, but
+of a selected group of the most hopeless cases. In the first place the
+more capable individuals escape the dragnet which lands the defective
+delinquents in an institution, and furthermore, because of liberal systems
+of probation, only the more incorrigible or the very stupid make up the
+bulk of the population of such places. Miss Augusta F. Bronner, assistant
+director of the Psychopathic Institute of the Juvenile Court of Chicago,
+from a careful study of five hundred and five cases of delinquent boys and
+girls in the Detention Home, chosen with as little selection as possible,
+finds the proportion of mentally subnormal among them to be less than ten
+per cent.
+
+=Many Prisoners Mentally Subnormal.--=Doctor Walter S. Fernald, of the
+Massachusetts School for Feeble-minded, estimates that "at least 25 per
+cent. of the inmates of our penal institutions are mentally defective."
+Among the various available estimates at hand this seems to be a fairly
+conservative approximation. Hastings H. Hart points out that this
+calculation of 25 per cent. means that there are 20,000 adult defective
+delinquents in prison, and 6,000 youths in juvenile reformatories, or a
+total of 26,000 in custody in the United States.
+
+=The Inhibitions Necessary to Social Welfare Not Well Established in
+All.--=But let us look at this matter of delinquency a little more in
+detail. In common with other living creatures mankind has two strongly
+predominating instincts without which there can be no prolonged individual
+or racial existence, namely, the self-preservative and the reproductive.
+Says Schiller: "While philosophers are disputing about the government of
+the world, Hunger and Love are performing the task." Under
+self-preservative would be included everything pertaining to food,
+property and self-protection. In addition, however, man, together with
+certain other social animals, has developed a third set of activities or
+instincts--an impulsion toward the preservation of the community to which
+he belongs--and so far has this evolved in his case that it outranks in
+importance the other two. For the highest accomplishments and ideals of
+the race are in last analysis expressions of this social instinct. But
+with this system of mutual help comes the necessity of certain restraints,
+because for society to exist its members must impose upon themselves, or
+have imposed upon them, certain inhibitions of their self-preservative and
+reproductive instincts.
+
+Being a late acquisition of the race and less firmly ingrained, the social
+instinct is not well established in all individuals. Some have it
+sufficiently strong to exercise of their own accord the necessary
+inhibitions of other instincts. Experience has shown that others, either
+through a lack or through a wrong cultivation of it, can not or will not
+do so unaided. For the latter, society has instituted certain conventions
+and the criminal law whereby through a system of restraints and
+punishments such an individual is held in check either by actual physical
+restraint of his property or person or through the powerfully inhibitive
+factors of shame or fear. Man as a normal member of society must
+constantly take heed of the physical, intellectual or moral danger the
+exercise of a given feeling, action or procedure on his part will bring to
+humanity, and govern himself accordingly.
+
+But it is in just these very inhibitions that mental defectives are
+lacking. They are almost invariably anti-social types because they are
+unable to establish the personal abstentions which are necessary for the
+good of the community. While in the individual of innate normal mentality
+anti-social traits may have developed because of improper training or
+surroundings, in mentally defective types some factor or factors necessary
+to normality have been left out of their make-up and as a result they are
+often wholly lacking in social instincts or have these so feebly developed
+that education and exhortations toward social ideals are fruitless. We can
+not appeal successfully if there is nothing to appeal to; we can not
+develop something out of nothing.
+
+=The High-Grade Moron a Difficult Problem.--=One great difficulty in
+identifying the high-grade morons who are a bountiful source of our
+criminals is our almost universal failure to recognize that a memory test
+alone is not sufficient to determine the mental responsibility of an
+individual. Not only memory, but judgment, will-power and perhaps, also,
+to a lesser degree, the powers of attention and concentration are all
+indispensable elements in the make-up of a normal individual. There are
+cases on record of imbeciles with prodigious memories, yet hopelessly
+incapable of caring for themselves or of respecting the rights of others.
+In fact certain types of morons, usually cunning, often prepossessing and
+superficially clever, are characterized by good memories and will
+_moralize_ volubly, although their wills are too weak to inhibit impulses
+when they face temptation. It is obvious that just in proportion as the
+intelligence of the high-grade degenerate approaches normality and yet
+remains abnormal, the more dangerous he may become to society.
+
+=Degenerate Strains.--=A number of family records are now available which
+show convincing evidence of the hereditary nature of a degeneracy which
+finds expression in pauperism, immorality and crime.
+
+As has already been pointed out, there is reason to believe that much of
+this is based in some degree on feeble-mindedness. One of the most
+remarkable of these is the recent study on degeneracy by Goddard as set
+forth in his book called _The Kallikak Family_. The record is that of six
+generations of descendants from an original progenitor to whom the
+fictitious name of Kallikak has been assigned. This individual, descended
+from good stock, before his marriage met a feeble-minded girl by whom he
+became the father of a feeble-minded son. Later he married a normal woman
+by whom he had normal children. Thus from one normal father have sprung
+two lines of progeny, one vitiated with feeble-mindedness, the other
+normal. The comparison may be readily made by drawing up in parallel
+columns the data as follows:
+
+            LINE A                                 LINE B
+
+  In five generations 480 direct     In five generations 496 descendants
+  descendants from a normal father   from the same normal father as in
+  father and a feeble-minded         Line A and a normal mother have the
+  mother have been accounted for     following record:
+  as follows:
+
+  143 known to be feeble-minded.     All but one of normal mentality.
+
+  291 mental status unknown or       Two men known to be alcoholic.
+  doubtful.
+
+  36 illegitimate.                   One case of religious mania.
+
+  33 sexually immoral, mostly        Among the rest have been found
+  prostitutes.                       nothing but good representative
+                                     citizenship, numbering doctors,
+  24 confirmed alcoholics.           lawyers, educators, judges,
+                                     traders, etc.
+
+  3 epileptics.                      No epileptics or criminals.
+
+  82 died in infancy.                Only fifteen children died in
+                                     infancy.
+
+  3 criminals.
+
+  8 keepers of disreputable houses.
+
+  46 only ones known to ben ormal.
+
+Certainly there is abundant food for thought in these two records.
+
+If we take still other families of criminal or degenerate antecedents the
+same multiplication of viciousness, as a rule, is in evidence. Thus,
+_Margaret, the Mother of Criminals_, has left a progeny of some 700
+paupers, prostitutes and criminals, some of the women bearing as many as
+twenty children. The famous Jukes family, so often cited, with its 310
+professional paupers, 300 deaths in infancy, 440 physical wrecks from
+debauchery, 50 prostitutes, 60 habitual thieves, 7 murderers, and 130
+other convicts out of a total 1,200 descendants who have been identified,
+has alone cost the state of New York $1,250,000 in the care of its
+criminal, defective and immoral progeny.
+
+Another family record, the Zeros, reported by Poellman, of Bonn, starts
+with a female confirmed drunkard. In six generations of her descendants,
+totaling 800 people, Poellman found 102 professional beggars, 107
+illegitimates, 181 prostitutes, 54 in almshouse, 76 convicted of serious
+crime, 7 of murder, and costing some $1,206,000. Or we might cite the
+so-called _Tribe of Ishmael_, the progeny of a neurotic man and a
+half-breed woman. They have spread their ill-favored spawn over various of
+the central states in a veritable flood of imbecility and petty crime. And
+to these families may be added the records of _The Hill Folk_, _The
+Pineys_, or others of the several recent studies of degenerate strains.
+All bear the same message of rapidly multiplying degeneracy.
+
+=Intensification of Defects by Inbreeding.--=Most of these regional
+surveys that are now in progress show that there is particular danger in a
+population becoming broken up into small communities and isolated. Under
+such conditions there is a pronounced tendency to intermarry, and if
+deterioration is already present in the stock such communities become
+centers of marked degeneracy. The situation is well exemplified in the
+following excerpt from Davenport:
+
+    "I have been going over the records of one family in New York, the
+    so-called Nam family. There were 55 per cent. consanguineous matings,
+    marriage between cousins, in one generation, and, owing to the fact
+    that the strain was already loaded with defects, we can see how these
+    defects were concentrated by these cousin marriages, so that about 90
+    per cent. of the strain is feeble-minded. There were fully 90 per
+    cent. of the men who are unable to resist the lure of liquor.
+    One-fourth of the children are born illegitimates. Infanticides,
+    incest, murder, harlotry, are all over the chart. This is a highly
+    inbred community, keeping a nearly pure strain of social defects, and
+    the cost to the community has been a million and a half on a fair way
+    of figuring, not directly in the care, but indirectly in the damage
+    they have done. These constitute a rural community. Out of this
+    community we can trace those who have gone to the cities and become
+    murderers, prostitutes and thieves. They are not confined to one
+    state; they spread out over the country. One branch of the family came
+    to the state of Minnesota. We sent to one of Doctor Rogers' trained
+    field workers to learn whether she had ever heard of this family, and
+    received a reply that the family was well known to social workers in
+    the state of Minnesota. These strains of degenerates are not local
+    matters at all; they are matters of national interest."
+
+Concerning crime and delinquency, we find that all evidence tends to show
+that an alarming increase is in progress although satisfactory data are
+hard to obtain. It is certain that there is a tremendously
+disproportionate increase in the number of prisoners in recent years
+compared with general population, for while the total population has
+increased three and one-half fold, the prison element has increased
+fifteen fold. According to Wier, in this country there are four and
+one-half times as many murders for every million of our population to-day
+as there were twenty years ago.
+
+It may be urged that this increase in prison population is not a
+disproportionate increase in the number of defectives or criminals, but
+only an increase in the number sent to prison, and this is probably a
+partial truth--but when we recall such pedigree as those of the Nams, the
+defective line of Kallikaks and other known unsound strains, he must be
+hopeful indeed who can find much consolation in this supposition. In any
+event, no such uncertainty exists regarding the number of murders and
+homicides, since these have in all probability been as fully recorded in
+the past as at present.
+
+=Vicious Surroundings Not a Sufficient Explanation in Degenerate
+Stocks.--=It is sometimes urged that we are not dealing in such cases with
+degenerate strains, but merely with unfortunate individuals who have been
+subjected to pernicious surroundings from the beginning. And it can not be
+denied that parents who are mentally defective, dissipated or syphilitic
+afford most noxious developmental and environmental conditions for their
+children. But when one notes how intimately the moral degeneracy in such
+stocks is bound up with some degree of feeble-mindedness, he is strongly
+skeptical toward the sufficiency of such an interpretation, although
+environment undoubtedly intensifies the results. Concerning this point
+Davenport says:
+
+    "We have certain methods of testing whether it is bad environment or
+    bad breeding which produced these people. Some of the children have
+    been taken at an early age and 'placed out'. We have traced their
+    subsequent history. In most cases they have turned out quite as bad as
+    those who have remained at home. In a few cases they have turned out
+    well, but it is also true that some of the children who remained at
+    home in bad environment have turned out well."
+
+And to Davenport's testimony may we add that of Doctor Wilmarth, who,
+speaking of children at the home for feeble-minded, says:
+
+    "In no place is this subject of the power of heredity in relation to
+    environment so easily studied as among our children. A group of many
+    little children came to us from the state school, being untrainable
+    there. They have had with us the same teaching and the same
+    companionship. Each one has lived, eaten and slept among the others,
+    and, so far as we know, with but one exception, those of vicious
+    parentage have turned instinctively to vicious traits by preference,
+    while those of simple but honest stock do evil things only under
+    strong temptation, and do not persist in them after the wrong is
+    pointed out."
+
+=By No Means All Delinquents Are Defectives.--=One must not overlook the
+fact, however, that _delinquent_ and _defective_ are by no means
+synonymous terms, and that many delinquents are with little doubt the
+product of adverse social circumstances.
+
+The recent careful work of Doctor William Healy[13] in connection with the
+juvenile delinquents of Chicago shows convincingly that the underlying
+causations of delinquency are many. Such factors as immorality or constant
+quarreling of parents, bad companions, lack of parental control, defective
+sense organs, debilitating habits, lack of healthy mental interests and a
+host of other environmental factors are not infrequently sufficient in
+themselves to develop delinquency in the absence of inherited deficiency.
+The present-day efforts of the student of heredity should not be
+misunderstood. They are not attempts to make all delinquents out
+defectives, but rather to determine what percentage of delinquents may be
+legitimately reckoned as defective and to make the facts known. Since
+there is no longer any reasonable doubt that, to express it in the mildest
+terms, an amount of delinquency far from negligible is due in great
+measure to congenital omissions or propensities, then the sooner the
+public learns this the better, for we may then set about supplementing our
+present efforts at race betterment through external improvement by
+devising means of cleansing the fountain source as well.
+
+It can scarcely be doubted that the average man differs little if any in
+inherent personality and capacity from many a criminal who is such by
+occasion rather than by undue predisposition. Who can truthfully answer
+how many individuals there are who are not potentially criminals to some
+extent, given sufficient evocative conditions of ignorance, vice, adverse
+economic pressure and undue temptation?
+
+  "Virtue itself turns vice, being misapplied."
+
+=No Special Inheritable Crime-Factor.--=The main difficulty in trying to
+find a hereditary basis for crime lies in the multiplicity of things crime
+may be. The individual impulsions which lead to certain offenses may be
+utterly different from those which conduce to others. Undoubtedly many
+inborn tendencies which are perfectly normal or neutral in themselves may
+be warped by circumstances into the commission of what are classified as
+crimes. The moral man may have the same desire for a thing that the
+criminal does, but when he finds that this desire can only be gratified by
+injury to others, he inhibits it because of his repugnance to such injury.
+The criminal makes no such inhibition.
+
+In general, crime means an offense of some kind against person, property
+or state. But a biological analysis of it, could it be made, would require
+among other things knowledge of crime in terms of motive or lack of
+motive, whether the act was intended to benefit the perpetrator, some
+other person, or even the race or state; whether the offense was one of
+dishonesty, of cupidity, of lust, or of violence against another.
+
+As a matter of fact no satisfactory classification of crime can be made
+since so many factors enter and in such varying degrees. Most
+classifications made in our legal codes are a hodge-podge based on a
+mixture of motive on the part of the participant, degree of turpitude
+involved, nature and extent of the injury inflicted, and the object
+against which the offense was perpetrated, whether an individual, society
+or the state. Moreover, it must not be forgotten that in many instances
+what was crime in the past is no longer so, and vice versa many things
+which are regarded as criminal to-day were not considered so in the past.
+So the futility of seeking a specific inherent propensity for "crime" is
+manifest. How, for instance, in terms of hereditary determiners shall we
+draw the fine lines of distinction among those who bribe legislators and
+legal officials, those who are avaricious and dishonest in the world of
+trade, and those who are wilfully obtuse in providing proper safeguards
+for employees?
+
+=What Is Meant by a Born Criminal?--=All we can do is to fall back on the
+assurance that any act directly or indirectly injurious to society is an
+offense, and that those offenders who are congenitally unable to
+distinguish between what is generally accepted as right and wrong, or who
+if recognizing this are nevertheless uncontrollably impelled toward or are
+unable to refrain from anti-social acts because of some inherent condition
+of intellectual or volitional make-up, may be legitimately classed as
+individuals born with an aptitude for crime and social transgressions. In
+such individuals the natural mental make-up is lacking in some of its
+necessary elements so that memory, judgment, or will-power are not up to
+the minimum that is necessary for the establishment of proper conduct. In
+some cases, apparently, this lack finds expression in almost any kind of
+vice or crime into which circumstances happen to lead the individual. In
+others, however, there seem to be tendencies toward the commission of
+certain types of crime or vice. Certain family strains are characterized
+by petty thieving, others by deeds of violence, and still others by sexual
+offenses. Certain types of mental defect are closely associated with
+certain crimes. Thus sufferers from incipient paresis seem particularly
+prone to commit assaults and larceny; epileptics, crimes of brutality and
+violence.
+
+=The Epileptic Criminal Especially Dangerous.--=One of the characteristics
+of epilepsy, indeed, emphasized by various psychiatrists, is that
+frequently it leads to loss of those forms of self-restraint which are
+absolutely indispensable to morality and the safety of society. Cruelty,
+atrocious sexual offenses and other vicious crimes are the result. It is a
+noteworthy fact, moreover, that often in the milder forms of affliction,
+where instead of well-marked convulsions only momentary lapses of
+consciousness occur, the greatest amount of mental and moral deterioration
+and fluctuation is sometimes found.
+
+The situation as regards the epileptic is well presented by Doctor William
+Healy, Director of the Juvenile Psycopathic Institute of Chicago, in an
+article entitled "Epilepsy and Crime; the Cost", in the _Illinois Medical
+Journal_, November, 1912. He says:
+
+    "In the work of our institute,[14] which represents the most
+    thoroughgoing research into the genetics of criminalism ever
+    undertaken in this country, we have with the help of parents and
+    others carefully studied nearly 1,000 young repeated offenders. We
+    have found that no less than 7-1/2 per cent. of these are ordinary
+    epileptics, and we have reason to suspect others. This by no means
+    represents the total number of epileptics seen in connection with
+    juvenile court work, where, of course, first offenders as well as
+    large numbers of dependents are seen. In addition to my above
+    enumeration, other cases seen by the Detention Home physicians and
+    myself amount up to many scores of cases. If one remembers that it is
+    ordinarily calculated that one person in every 500 is epileptic, the
+    significance of this high criminal percentage is clear, and the
+    practical bearing of it is still further accentuated by the fact that
+    some of the worst repeaters are epileptics, and that many of the
+    gravest crimes are committed by those unfortunates. The connection
+    between epilepsy and crime has everywhere been recognized by students
+    of the subject, but it apparently needs constant emphasis in order
+    that common sense steps may be taken toward guardianship of these who
+    suffer from a disease which wreaks such extravagant vengeance on
+    society."
+
+=Mental Disorders Most Frequently Associated With Crime.--=Doctor Charles
+Mercier, an English authority on crime and insanity, in enumerating the
+mental disorders most frequently associated with crime, places the
+insanity of drunkenness first. Any one who will take the trouble to verify
+the facts in his own community will find that a large percentage,
+frequently considerably over half, of the arrests made by the police are
+for acts committed while the offender was more or less under the influence
+of alcohol. Next to drunkenness among mental disorders which lead to crime
+Doctor Mercier places feeble-mindedness. Next to feeble-mindedness comes
+epilepsy; then paranoia or systematized delusion; next paresis; and lastly
+melancholia.
+
+Paranoics are peculiar in that they are particularly apt to attack persons
+of prominence. Highly egotistical, they almost invariably believe
+themselves or some one or some cause dear to them, the subject of a plot,
+perhaps to rob them, to torture them, to steal their inventions or
+literary productions, or to persecute them in some way. Two if not three
+of our murdered presidents owe their assassinations to paranoics. Many
+rulers have been attacked and some killed by such insane individuals. Most
+of the "cranks" who write threatening letters are lunatics of this type.
+
+Of the kinds of mental unsoundness known to be inheritable which are of
+special significance from the standpoint of crime and delinquency
+undoubtedly feeble-mindedness ranks first. We have already seen that as
+our methods for detecting the higher grades of feeble-mindedness become
+more accurate we disclose in border-line cases a veritable hot-bed of
+mental incapacity suitable for the engendering of the criminal and the
+vicious. Here in addition to some of the more pronounced criminal types
+belong hosts of our chronic petty offenders, our sexually vicious and our
+"won't-works". One interesting outcome of a recent investigation into the
+army of unemployed in England was the discovery of the general unfitness
+of these unemployed. In our own country the habitually unemployed are so
+not because of lack of work, but largely because it is unprofitable to
+employ them.
+
+=The Bearing of Immigration on Crime and Delinquency.--=Perhaps in no
+field more than this of crime and delinquency, especially in so far as it
+is based on innate deficiency, does the gravity of the immigration
+question impress itself on us. How stupendous this problem[15] has become
+may be realized from the fact that according to the census of 1910,
+13,345,545, or one out of seven of the inhabitants of the United States,
+were foreign born. And if we add to these the 18,897,837 of whom one or
+both parents were of foreign birth, we reach the astonishing total of over
+32,000,000, or more than one-third of our total population, who are
+foreign born, or who have one or both parents of foreign birth.
+
+During the decade from 1900 to 1910, 8,500,000 foreigners came to the
+United States, of whom 5,250,000 remained to make a permanent home. This
+shows how rapidly our whole population might be radically changed. In
+recent years the source of our immigrants has shifted proportionately from
+northwestern Europe to southern and eastern Europe (Italy, Austria-Hungary
+and Russia), and whether for weal or woe this new blood must inevitably
+leave its impress upon us. Does it not behoove us then to seek with
+anxious eyes some knowledge of these invading hordes with whom we are to
+mingle our life-blood?
+
+Even the most superficial examination may well cause us grave concern. We
+find that in one year (1908) at Ellis Island alone, 3,741 paupers, 2,900
+persons with contagious disease, 184 insane, 121 feeble-minded, 136
+criminals, 124 prostitutes and 65 idiots were denied entrance, and yet,
+according to the estimate of Doctor F. K. Sprague, of the United States
+Public Health Service, probably only about 5 per cent of the mentally
+deficient and 25 per cent. of those who will become insane have been
+detected. When confronted by such data we can begin to realize what we are
+facing. Others estimate that from 6 to 7 per cent. of the immigrants who
+are now arriving are feeble-minded. We learn further that recently while
+the foreign-born population of New York state was about 30 per cent., the
+foreign-born population of the insane hospitals of the state was over 43
+per cent., and at one time approximately 65 per cent. for New York City.
+In one year (1908) 84 per cent. of the patients in Bellevue Hospital, New
+York City, were of foreign parentage. Paresis, which probably always has
+syphilis as its antecedent, is proportionately twice as prevalent among
+foreigners as among natives in New York City.
+
+But from the standpoint of inheritance, however great the danger may be
+from classifiable defectives, it is probably far greater from that much
+larger class of aliens we are now receiving with open arms who are below
+the mental and physical average of their own countries. Moreover, with our
+present system of inspection there is no way of detecting the grades of
+feeble-mindedness above idiocy and imbecility in the great numbers of
+foreign children under five when brought in, who are beginning to show up
+in alarming numbers in the schools of some of our larger cities. About
+thirty per cent. of the annual increment of our population is due to
+immigration and not to births; and once in our country the alien far
+outbreeds the native stock, with relatively little increase in death-rate,
+thus making a double contribution to the increase of population. When we
+take all these facts into consideration it certainly is high time that we
+arouse from our self-complacent attitude and consider the whole question
+of immigration most earnestly.
+
+In spite of the fact that many individuals are caught in the net of
+inspection at our portals, it is clear that still more rigid rejection[16]
+is imperative. The inspectors at our various ports are doing the best
+they can under the circumstances, but there are at present too few of them
+and they are too restricted in their powers to meet the situation
+satisfactorily. Moreover, when at one of our ports in one year (1910), of
+1,483 immigrants certified by the inspecting surgeons as unfit to land
+because of serious mental or physical defects, 1,370 were landed anyway,
+it is evident that there is a strong and reprehensible pull somewhere to
+evade the obvious intent of the law.
+
+It remains for us as a people to decide whether we shall continue to let
+the large employers of cheap labor, the railroad and steamship agents and
+brokers, who care nothing about the innate fitness of the immigrants they
+bring, determine the character of our future population, or whether we
+shall insist on a proper regulation of this flood so that we may receive
+only an honest, intelligent, industrious and healthy stock. To continue to
+absorb these aliens with as little selection as we now do is nothing short
+of criminal carelessness. Let us not be deceived by the promptings of a
+misguided sentiment, "The voice is Jacob's voice, but the hands are the
+hands of Esau." The voice is Jacob's voice, nor should this voice of the
+easily persuaded, the sentimentalist, the interested organization to which
+the relatives of the defective alien belong, or any other pressure move us
+from our obvious duty of refusing to fasten upon this country an incubus
+of degeneracy for which we as a nation are in no way responsible.
+
+To render us safe we should not only have more carefully drawn laws and
+more rigid selection at our ports of entry, but we should if possible
+also know the stock from which our future citizens come. This is
+peculiarly desirable for such defects as feeble-mindedness and various
+other mental imperfections, some of which require prolonged observation
+for detection. Davenport estimates that it is wholly within the realm of
+possibility and good business sense to maintain a corps of trained
+inspectors abroad in the chief centers from which our immigrants come who
+shall certify the desirable applicants. He makes the point that the
+national expense would be far less than the cost of maintaining the army
+of defectives we are now admitting to our own country, many of whom almost
+immediately become public charges, to say nothing of the hordes of
+carriers who though normal themselves, will transmit undesirable traits.
+
+=Sexual Vice.--=As to sexual vice, the skein is indeed a tangled one.
+Since nine-tenths of the difficulty centers in a lack of self-restraint,
+and inasmuch as the mating instinct is one of the strongest that tugs at
+the flesh of humanity, it is obvious that those by nature deficient in
+volitional control will almost without exception give way to the call. So
+as might be expected the hordes of our feeble-minded and epileptic are
+always a source of grave danger in this respect. However, the mentally
+enfeebled are by no means the only offenders; indeed, they are probably
+not the majority. The true situation is finally dawning on society and the
+reformer's call for instruction in "sex-hygiene" resounds through the
+land. The whole matter is one of the most perplexing and momentous that
+confronts us to-day.
+
+=The Question of School Instruction in Sex-Hygiene.--=While the writer
+does not for an instant underestimate the gravity of the situation, and
+has only contempt for the nonsense that is palmed off on children about
+their origin, or the indelicate self-consciousness which puts under the
+ban the discussion of so serious a problem by adults, still he is not
+convinced that the universal teaching of the subject to children in
+schools by the average teacher, as advocated by some, is to be the
+solution of the matter or is even a wise attempt at solution. Yet he
+freely admits that he is possibly overfearful of the effects of the
+undesirable features of such instruction. True it is that all children do
+learn, frequently at an astonishingly early age, about sex, and their
+knowledge is usually of an undesirable kind from unreliable and often
+vicious sources, and it is equally true that parents, either through
+ignorance or prudery, generally can not be depended on to give the child
+necessary instruction. But before entering on a wide-spread campaign of
+undiluted sex-instruction in schools might it not be more prudent to make
+an attempt toward reaching fathers and mothers and convincing them of the
+necessity of dealing more frankly and intelligently with their children
+regarding sex?
+
+Even to the novice in psychology the powerful nature of suggestion is
+known, and with this knowledge before us, is it not wiser to strive in the
+main to keep the child's mind off of sex rather than specifically to focus
+it on it by special convocations and discourse? If our psychology means
+anything, then the worst possible thing we can do for a child is to make
+him unduly sex-conscious. Something might be done profitably perhaps in
+schools in an unobtrusive way by specially gifted persons, but the
+self-conscious way in which most teachers go about topics of sex is
+certainly not reassuring to the thoughtful observer as regards the benefit
+derived from such instruction. The one evident method of accomplishing
+wholesome sex-instruction in schools, devoid of all possibility of
+undesirable suggestion and sex-consciousness, is in the form of biological
+work where plants and animals are studied in all their relations, the
+subject of propagation being taken up in as matter-of-fact a way as the
+functioning of any other organ system of plants or animals. In such a
+course, long before the subject of sex in higher animals need be
+approached the pupil will have developed an attitude of mind which will
+lead him to see nothing unusual or suggestive in the function of sex no
+matter where it may be found. Incidentally, inasmuch as the manner in
+which germs affect living organisms should be studied in such a course
+anyway, it would be a simple matter to give all necessary information
+about the dangers of infection from venereal diseases.
+
+=Mere Knowledge Not the Crux of the Sex Problem.--=However, desirable as
+correct knowledge about sex is, knowledge alone is not the crux of the sex
+problem. The moral dangers and abuses that we are trying to circumvent lie
+rather in the realm of the emotions than that of the intellect. The
+problem must be solved from a broader foundation than mere information.
+The all-important consideration is the early establishment of general
+habits of self-control so that these may become incorporated in the
+nervous organization of the child and become inhibitory anchors against
+passions and temptation. Children must be taught to suppress the present
+impulse, to sacrifice the immediate pleasure for the more distant or
+permanent good. They must be practised in calling up feelings that will
+counteract other promptings which if followed blindly are inimical to
+social welfare. Their control must come from within not as a matter of
+external compulsion. That way character lies.
+
+So in viewing the problem of sexual hygiene the writer feels that our
+attempts toward damming the torrents in the adolescent by a belated effort
+at verbal instruction on sex-hygiene is at best only a palliative or an
+attempt to cure the symptoms of a more deeply-seated, organic, social
+malady. The treatment should have been in progress long before in the form
+of training in self-control, and in the inculcation of the sense of
+dignity and self-respect which springs from the individual's consciousness
+of being, not a slave to his desires, but his own master. This, together
+with the judicious schooling of boys in a greater chivalry and respect for
+womanhood, and of girls in the necessity of meriting such esteem, will, in
+my estimation, carry us further than formal courses in sex-hygiene.
+
+=Early Training in Self-Restraint an Important Preventive of Crime and
+Delinquency.--=As to crime and delinquency in general, it is evident that
+the same early training in self-restraint is a most important factor of
+prevention. A wise warden in charge of a large prison says, "Most of these
+men are here because they have not learned sufficiently the lesson of
+self-control." This is the age of preventive medicine, why not also of
+preventive crime and delinquency? Instead of confining our practise to
+punishing offenders, necessary as this may be under the present
+conditions, why not strive more to prevent the commission of offenses? As
+far as normal individuals are concerned much can be done by early
+cultivation in self-discipline and through the establishment of moral
+backbone by training in the overcoming of difficulties. Much, very much,
+also remains to be done in the correction of wrong social conditions.
+
+=Unpardonable to Permit Delinquent Defectives to Multiply Their Kind.--=As
+for our mental defectives and moral imbeciles, knowing now how strongly
+hereditary the underlying factors of these conditions are, and with no
+preventive or curative agents in sight, to let them produce progeny, is
+clearly unpardonable.
+
+
+
+
+CHAPTER X
+
+RACE BETTERMENT THROUGH HEREDITY
+
+
+Most of us have heard in one form or another the fairy story of the youth
+on adventure bent, who was captured by the giant and under dire penalty in
+case of failure was set the task of sweeping out the giant's stable before
+sundown. The peculiarity of this stable, it will be recalled, was that, as
+fast as the refuse was swept out at the door an even greater quantity
+poured in through the windows so that the sweeper, just in proportion to
+his zeal, became more and more encumbered with his burden.
+
+=A Questionable Form of Charity.--=Though we smile at the childishness of
+this legend, are we not as a civilized people attempting through our
+charities a feat parallel to that of this unfortunate youth? We foster and
+favor our social wastage with the inevitable result that it runs riot
+under our sheltering hand and deluges us with an ever accumulating flood
+of its like. For are we not constantly building more asylums, sanitaria
+and prisons, to preserve more unfit, to produce more defectives, to
+require still greater numbers of asylums, sanitaria and prisons, to
+preserve more unfit, and so on in unending progression?
+
+At nearly every period of history there have been certain individuals who
+have seen the necessity of a state eliminating its supply of defectives.
+
+=Past Protests.--=For instance, we find the importance of this strongly
+urged by Plato. After pointing out the fact that the shepherd, in order to
+maintain the standard of his flocks, bred only from the best individuals,
+as did likewise the huntsman with his dogs and horses, and the fancier
+with his various pets, Plato went on to show the danger to the state of
+allowing the constantly increasing body of defectives and degenerates to
+multiply their kind. Repeated expression of the same idea has occurred
+from time to time during the succeeding centuries.
+
+Little heed was paid to these remonstrances, however, with the result that
+is known to us all. To-day, "the glory that was Greece and the grandeur
+that was Rome" is still sung by the poet, but the original nations
+themselves have long since passed into the night.
+
+=An Increasing Flood of Defectives.--=Strive to ignore the unpleasant
+facts as we may, we have to admit that the same problem of what the human
+harvest shall be is with us in grave form to-day. The alarming phase of
+the situation, however, lies in the fact that we are facing an ever
+increasing flood of social wastage.
+
+But _why_ this increase of defectives? It can not be attributed to
+oppression, to grinding poverty, or to decline in attention to our sick
+and needy, for never was prosperity greater, never were charities more
+flourishing, never such activity in the search for palliatives and cures.
+The simple fact is that we are breeding our defectives. The human harvest
+like the grain harvest is based fundamentally on heritage. And to get a
+better crop of human beings, we must, as with other crops, weed out bad
+strains.
+
+To whatever source of information we turn the facts are essentially the
+same. Abroad we find that in England, for example, the ratio of defectives
+to normals more than doubled between 1764 and 1896. At home, from the
+investigation of Davenport and Weeks we learn that in the state of New
+Jersey the number of epileptics doubles every thirty years. And other
+investigators estimate that the fecundity of mental defectives in general
+is about twice as great as that of the average of our population. In a
+recent report of the New York State Board of Charities we read, "There are
+about thirty thousand feeble-minded persons in the state of New York, of
+whom four thousand are intermittently sequestered while twenty-six
+thousand who are a menace to society are at liberty and may produce the
+unfit." And a passage from the last Massachusetts report reads as follows:
+"We have been obliged to refuse a very large number of applicants for the
+admission of feeble-minded women--many of whom have given birth to one or
+more children. The prolific progeny of these women almost without
+exception are public charges from the date of their birth."
+
+How fertile defective types may be is shown by a passage in one of Doctor
+Wilmarth's papers which runs as follows: "One feeble-minded woman, now
+removed from this state, had by different men eighteen children in
+nineteen years, she alleges." In a letter Doctor Wilmarth tells me that
+the birth of the twenty-third child of this woman has just been
+announced! In one English workhouse Potts reports sixteen feeble-minded
+women who have produced one hundred sixteen mentally defective children,
+and Branthwaite ninety-two female habitual drunkards who have had eight
+hundred fifty babies. If we include the two million individuals cared for
+annually in various institutional homes, hospitals and dispensaries as
+dependents, the estimated total of insane, feeble-minded, epileptic, deaf
+and dumb, criminals, juvenile delinquents, paupers and other dependents in
+the United States in 1910 was approximately three million, or one in every
+thirty of our population! With the higher fertility of certain of these
+classes and with only a small percentage under custodial care where will
+it all end? Is it not time for us to waken from our lethargy and stem this
+tide of national deterioration?
+
+=Natural Elimination of Defectives Done Away With.--=With our improved
+methods of sanitation and care of the sick, the pauper and the defective,
+these classes have been freed from the stress of an environment that under
+natural conditions would have resulted in their premature death and
+consequent infertility. Or in the terminology of the biologist, we have
+done away with the factor of _natural selection_, the factor which in
+state of nature keeps all races purged of the unfit, the ill-adapted. With
+this restraining, and purifying influence removed, however, the weakling,
+the defective, may arrive at maturity and commingle his blood with that of
+the strong, with the inevitable result that the general vigor of the
+progeny from generation to generation is sapped and progressively
+undermined. Thus we are confronted by the stubborn fact that through
+present humanitarian methods we are driving the race toward decadence.
+
+=Why Not Prevent Our Social Maladies?--=Now there is no reasonable person,
+I think, who will not admit that the motives underlying our modern
+altruistic practises are the noblest fruitage of our slow upward struggle
+from the brute to man. As humane beings, we can not cast aside these
+principles and return to the painful and pitiless method of nature which
+would leave the sick and the defective alone to perish miserably; the
+sacrifice would be too great.
+
+Is there then no escape from this dilemma? To this query the modern
+student of heredity answers yes; let us but add more wisdom to our charity
+and the enigma is solved. We need no sacrifice of pity but rather an
+expansion of it. Let us but extend our vision from immediate suffering to
+the prospective suffering of the countless unborn descendants of our
+present unfit and ask ourselves the question, why should they be born? Why
+not prevent our social maladies instead of waiting to cure them? This is
+the province of eugenics.
+
+=Eugenics Defined.--=The term Eugenics was coined in 1883 by Francis
+Galton in his book entitled _Inquiries Into Human Faculties_, and we may
+therefore look to him for a satisfactory definition. He says, "Eugenics is
+the study of the agencies under social control, that may improve or impair
+the racial qualities of future generations, either physically or
+mentally." And again, "I take Eugenics very seriously, feeling that its
+principles ought to become one of the dominant motives in a civilized
+nation, much as if they were one of its religious tenets.... Man is gifted
+with pity and other kindly feelings, but he also has the power of
+preventing many kinds of suffering. I conceive it to fall well within his
+province to replace natural selection by other processes that are more
+merciful and not less effective. This is precisely the aim of Eugenics.
+Its first object is to check the birth-rate of the unfit instead of
+allowing them to come into being, though doomed in large numbers to perish
+prematurely. The second object is the improvement of the race by
+furthering the productivity of the fit, by early marriages and the
+healthful rearing of their children."
+
+=Improved Environment Alone Will Not Cure Racial Degeneracy.--=While many
+an enthusiastic humanitarian is laboring under the assumption that if we
+can improve external conditions human deficiencies will disappear, the
+student of heredity realizes that this is in large part a delusion unless
+we can secure an accompanying improvement in intrinsic qualities of the
+human species itself through the suitable mating of individuals. Just as
+the intelligent farmer to-day demands selected seed as well as good soil
+and proper cultivation, so one with the facts of heredity at hand would,
+as he views social problems, urge the fundamental importance of having
+selected stock with which to start. No shifts or shapings of environment
+will ever enable men to "gather grapes of thorns or figs of thistles."
+
+=Heredity and Environment.--=To wrangle over the question of which is the
+more important, heredity or environment, is about as idle a proceeding as
+to argue which is the more important, the stomach or something to put in
+the stomach. Man would soon come to grief without either. So, too, the
+question of human development is not one of heredity alone nor of
+environment alone; both are necessary and must work hand in hand. Dormant
+capacities must have proper environment to call them forth, but on the
+other hand no kind of environment can evoke responses if some degree of
+aptitude is not present.
+
+Professor Thorndike undertook experiments with groups of school children
+of high and of low initial ability respectively to determine whether equal
+opportunity or equal special training would produce an equalizing effect
+in easily alterable traits such as rapidity in addition and the like.
+Without exception he found that at the end of such experiments, although
+both groups had improved, the superior individuals were farther ahead than
+ever, that equality of opportunity and training had widened rather than
+narrowed the gap between the two classes. Others who have made special
+studies on the causes of individual differences have come to the same
+conclusion; namely, that individuals differ widely by original nature and
+that similarity in conditions of nurture and training will not avail in
+deleting these differences.
+
+Galton and others, from extensive studies based on English sources, have
+shown that notable achievements have run in certain families to a degree
+that is inexplicable on the basis of opportunity alone; it can be fully
+accounted for only by attributing much to superior inborn capacity. Doctor
+Woods has shown much the same thing for certain families in America.
+Schuster and Elderton have proved that there is a high degree of
+similarity in scholastic standing between fathers and sons in Oxford.
+Professor Pearson's measurements of mental characters in brothers and
+sisters while at school show a high degree of innate resemblance in many
+cases and certain cases of decided contrast. Where contrasts exist in
+certain families they remain unreduced in spite of the similarity of
+environment, thus proving that environment is less operative in the final
+intellectual establishment of such individuals than are their inborn
+aptitudes. Even in twins, as both Galton and Thorndike have shown, there
+is no tendency for similar education, home life and the like to render
+those originally different any more similar with advancing years.
+
+Professor Karl Pearson has done more perhaps than any other individual
+toward attempting actually to measure the relative strength of heredity
+and environment. Numerous statistical measurements lead him to conclude
+that it is a conservative estimate to regard heredity as at least five or
+ten times as important as environment in the development of the
+individual. A vigorous defense by him of this position will be found in
+_Biometrika_ for April, 1914.
+
+=Inter-Racial Marriage.--=Some of the dangers of racial deterioration
+which threaten us because of our laxity regarding immigration have already
+been indicated. It is high time that we give this whole question the most
+serious consideration of which we are capable. From the rate at which
+immigrants are increasing it is obvious that our very life-blood is at
+stake. For our own protection we must face the question of what types or
+races should be ruled out. Aside from the dangers which lie in the
+defective or unsuccessful types already discussed in Chapter IX, many
+students of heredity feel that there is great hazard in the mongrelizing
+of distinctly unrelated races no matter how superior the original strains
+may be. Unfortunately there is a great lack of reliable data on this
+point. The mulatto of our own country, the Eurasians in India and the
+mixed races of South America are, according to the testimony of many
+observers, eloquent arguments against such hybridization. Agassiz remarked
+on this point as follows:
+
+    "Let any one who doubts the evil of the mixture of races and who is
+    inclined from mistaken philanthropy to break down all barriers between
+    them come to Brazil. He can not deny the deterioration consequent upon
+    the amalgamation of races, more wide-spread here than in any other
+    country in the world, and which is rapidly effacing the best qualities
+    of the white man, the Indian, and the negro, leaving a mongrel
+    nondescript type deficient in physical and mental energy."
+
+Of the American mulatto one not infrequently meets with the assertion that
+he is on the average inferior mentally, morally and physically to either
+the white or the negro race. Thus Doctor J. B. Taylor[17] states that,
+"It is demonstrated by well-attested facts that these hybrids of black and
+white are vastly more susceptible to certain infections; their moral as
+well as physical stamina is lower than that of either original race."
+Others would deny that conclusive evidence to this effect exists. However,
+it is certain that under existing social conditions in our own country
+only the most worthless and vicious of the white race will tend in any
+considerable numbers to mate with the negro and the result can not but
+mean deterioration on the whole for either race.
+
+There is certainly not one iota of evidence that the crossing of any two
+widely different human races will yield superior offspring in any respect
+and there are many indications that such intermixture lowers the average
+of the population. Our evidence derived from plant and animal breeding is
+also against pronounced crosses. The inferiority of the mongrel is
+universally recognized. No sane farmer, for example, would seek to improve
+his Jerseys or his Herefords by crossing one with the other. It is true
+that in pure breeds of plants and animals we sometimes venture on a cross
+to introduce some new desirable character but we follow up such mixture by
+a rigid selection in which is eliminated all but the rare individuals
+having the desired characteristics, and we continue this elimination
+generation after generation to fix our characters again. It is obvious
+that no such selection as this would be possible among the progeny of
+human crosses.
+
+It clearly becomes our duty then to determine as accurately as possible
+the degree of non-relationship between races it is inadvisable to
+transcend in inter-racial marriages. We are certainly taking great risks
+in accepting in any considerable numbers those races we can not assimilate
+to advantage into our own stock.
+
+=War.--=The deteriorating effect of war on national physique and vigor has
+been so frequently cited by eugenists[18] and is so obvious as scarcely to
+require further comment. It should be pointed out, however, that where, as
+is the case at present in Great Britain, armies are assembled from
+volunteers, instead of by conscription, there is the greatest danger from
+the eugenic standpoint, since not only physical but moral qualities are
+involved. For it is the brave, the generous, the individual with a high
+sense of duty who goes forward to the slaughter leaving the cowardly, the
+selfish or the indifferent to father the race. With the awful deadliness
+of modern warfare upon exhibition before our very eyes to-day, the extreme
+seriousness of such selective action must be evident to every thoughtful
+person.
+
+=Human Conservation.--=We talk much in recent years of _conservation_; but
+what are our forests and frontiers, our minerals and our waterways,
+compared with our national health and life-blood? No farmer would think of
+setting aside a diseased or physically defective _animal_ for breeding
+purposes, yet the same man together with the majority of mankind is wholly
+oblivious to similar faults when it comes to the mating of human beings.
+But is it not as important to look to fitness in man as in Poland China
+hogs or Holstein cows? Certainly the various strains are as marked and
+breed as true in the human family as in our live stock. Why face
+complacently in our own families what we would not tolerate in our
+piggery?
+
+From the expenditure of comparatively small sums in studying the
+inheritance of various qualities in wheat, corn and other grain,
+improvements based on the laws of genetics have been secured which are
+enormously increasing our agricultural output and thereby adding to our
+national wealth. But if it costs relatively little to discover and
+conserve millions of dollars' worth of hereditary qualities in our plants
+and animals, what are we to think of ourselves, an intelligent people who,
+knowing that "every good tree bringeth forth good fruit, but a corrupt
+tree bringeth forth evil fruit," still go on placidly permitting the
+production of defectives and delinquents? Can we continue to drink the
+sluggish blood of the pauper and the imbecile into our veins and hope to
+escape unscathed?
+
+We are all familiar with the fate of Babylon, Assyria, Persia, Egypt and
+Rome. Why not America? Certainly we have no pledge of special immunity
+from Divine Powers. If so, what then is the meaning of our 366 hospitals
+for insane which cost us annually $21,000,000; our 63 institutions for
+feeble-minded costing us over $5,000,000; our 1,300 prisons maintained at
+a cost of more than $13,000,000; our 1,500 hospitals whose annual
+maintenance requires at least $30,000,000; our 115 schools or homes for
+deaf and dumb; our 2,500 almshouses with an annual expense account of
+$20,000,000 and our 1,200 refuge homes costing annually several millions
+of dollars more? To say that we spend annually over $100,000,000 on the
+custody of insane, feeble-minded, paupers, epileptics, deaf, blind and
+other charges is expressing the situation very conservatively.
+
+=Kindness in the Long Run.--=There is no one I think who will not admit
+that the sympathy and charity of the human heart are its noblest virtues.
+But we must face the problem of what is kindness in the long run. Havelock
+Ellis well says, "The superficially sympathetic man flings a coin to the
+beggar; the more deeply sympathetic man builds an almshouse for him so
+that he need no longer beg; but perhaps the most radically sympathetic of
+all is the man who arranges that the beggar shall not be born."
+
+What shall we do?
+
+=The Problem Has Two Phases.--=For an intelligent consideration of the
+problem one must recognize at the outset that it has two distinct phases;
+namely, (1) a selective union of the fittest, or in other words, a
+conscious attempt to breed a superior race; and (2) the elimination of the
+obviously unfit by preventing their reproduction, with the purpose of
+purifying the present race. It is evident at a glance that these are two
+essentially distinct problems although the practise of either method could
+result in racial improvement. The first is sometimes spoken of as
+_positive_ or _constructive eugenics_, the second as _negative_ or
+_restrictive eugenics_.
+
+=Constructive Eugenics Must Be Based on Education.--=As to the first
+phase, direct selection for superiority, the campaign must, in the very
+nature of things, be one of education. With the necessary knowledge of the
+facts in mind, the awakening conscience of the individual together with
+an enlightened public opinion will form the safest guide. Increasing
+popular comprehension of the inevitable nature of human inheritance must
+engender a sense of responsibility as to the positive eugenic fitness of a
+contemplated marriage. The growth of this sentiment will doubtless be
+slow, and properly so, for as yet we have but half-lights on what are the
+most desirable types of humanity. No one can say what the highest type of
+man should be, but almost any one can readily pick out types which
+certainly should _not_ be.
+
+=Inferior Increasing More Rapidly Than Superior Stocks.--=Modern
+eugenists, although realizing that the constructive phase is of great
+importance, are making no attempt to map out any fixed mode of procedure
+for it beyond pointing out the desirability of larger families among the
+better classes. The need for individuals of superior physical, mental and
+moral qualities to multiply is so obvious as scarcely to require comment.
+Yet the fact is that judging from all appearances these are the very ones
+who have the lowest birth-rate. Eugenics is mainly concerned with the
+relative rates of increase of the various classes, not with mere fertility
+in itself. And the actual increase must be measured in terms of the extent
+to which birth-rate exceeds death-rate. If a high birth-rate is
+accompanied by a high death-rate then it is not especially significant in
+increasing a given class as a whole. All available evidence points to the
+fact that to-day the lower strata of society are far outbreeding the
+middle and higher, with an almost negligible difference in death-rate, and
+just in the measure that these lower strata are innately inferior just in
+that degree must the race deteriorate. The seriousness of the whole
+situation as it exists to-day hinges, therefore, on the extent to which
+the lower strata are inferior to those above them.
+
+=An Unselected Population May Contain Much Valuable Material.--=In
+evaluating these lower strata a matter of very great importance is whether
+the population is a selected or an unselected one. If the population has
+been long resident in a given region and has had fairly good opportunity
+for education then we will find in the lower reaches a larger percentage
+of sedimentation made up of the worthless and inferior stocks. If,
+however, a continual fomentation and geographical shifting of the
+population is in progress as in parts of America, or if adequate
+educational opportunities are lacking, as in some parts of Russia, the
+poor and less well-to-do classes may contain, no one can tell how much,
+relatively valuable stock.
+
+Forel remarks on this point as follows:
+
+    "If we compare the nature of delinquents, abandoned children,
+    vagabonds, etc., in a country where little or nothing has been done
+    for the people (Russia, Galicia, Vienna, etc.), with that of the same
+    individuals in Switzerland, for example, where much has already been
+    done for the poor, we find this result: In Switzerland, these
+    individuals are nearly all tainted with alcoholism, or pathological
+    heredity; they consist of alcoholics, incorrigibles, and congenital
+    decadents, and education can do little for them because nearly all
+    those who have a better hereditary foundation have been able to earn
+    their living by honest work. In Russia, Galicia, and even in Vienna,
+    we are, on the contrary, astonished to see how many honest natures
+    there are among the disinherited when they are provided with work and
+    education."
+
+=The Lack of Criteria for Judging Fitness.--=Barring the untold hordes of
+actual defectives who have gravitated into this lower stratum, there are
+few positive criteria by which we can measure the real fitness of the
+remainder. Before we can set out on a campaign of positive eugenics we
+must have some standard by which to steer, and it would be a rash advocate
+indeed who would assert that class distinction alone, or even success as
+measured by public opinion to-day should be our whole criterion of
+fitness. Shall we measure fitness in terms of how successfully one can
+acquire worldly goods, or in other words, by the property test, or what
+shall be our standard?
+
+=The College Graduate.--=Many of our modern critiques of the birth-rate
+situation make much of the fact that our college graduates as a group are
+scarcely reproducing themselves. According to Davenport, Bryn Mawr College
+between 1888 and 1913 has graduated 1,193 bachelors of arts, but these
+women have produced up to January, 1913, only 263 girls to take their
+place in the next generation. He also points out that statistics on some
+of the graduate classes of Harvard of twenty years ago or earlier show
+that they are little more than maintaining themselves; thus one class of
+328 graduates twenty years later had produced 195 sons, and in another
+case a class of 278 individuals had produced, twenty-five years later, 141
+sons. Relatively similar statistics can be cited for other eastern
+colleges.
+
+All such cases of college graduates cited as especially deplorable
+declines in birth-rate are based on the assumption that these individuals
+are a particularly superior stock.[19] But one might question this premise
+as a generalization. It may or may not be true. Are they superior or have
+they had mainly a combination of luck and incentive, luck in that their
+parents had sufficient means, acquired possibly through their own
+superiority, possibly not, to send them to college, and incentive derived
+from a fortunate environment which awakened a desire in them--or in their
+parents for them--for college education? Is the woolly-witted son of
+opulence, so abundant in our colleges to-day, who is boosted through by
+hook or by crook, of superior eugenical value to the alert eager boy--and
+his name is legion--destined for economic reasons to go to work at or
+before the completion of his high-school course, perhaps because of the
+very fact of an unlimited fecundity in his own family which necessitates
+his help for the general support?
+
+When one first learns of the declining birth-rate among college women and
+men he feels appalled, but immediately the question flashes up, if this is
+_the_ superior stock, and up to date it has died out or is dying out
+rapidly, whence then this ever augmenting rush of young folk who fairly
+deluge our universities and colleges to-day? Does it not rather point to
+the fact that in our own country at least, the man who will and can take
+a college education successfully is not so much the product of breeding
+from college men, but of a prosperity which leaves a sufficient surplus in
+the family exchequer to enable sons and daughters to go to college, and is
+it not reasonable to suppose that there is yet an abundant stock back of
+these who similarly await but the golden touch of opportunity? When we
+consider such men as Carlyle, Lincoln and a host of others who were not
+the sons of collegians, although we may be university pedigreed ourselves
+we can not but feel doubtful of the validity of a premise which takes a
+college stock unqualifiedly as having any considerable monopoly of innate
+superiority. After all, college can mean little more than opportunity, and
+the obtaining of such opportunity in this world of economic maladjustments
+and accidents of social position is too largely a matter of chance, at
+least in America, to stamp the possessors of these advantages, on this
+criterion alone, as of inborn superiority. Undoubtedly much that is
+intrinsically good now slumbers in the lower strata of society because of
+lack of favorable environment to call forth the latent possibilities.
+
+=Native Ability, Independence and Energy Eugenically Desirable.--=Although
+we can not sift out with certainty the superior from the inferior in our
+normal population by the property test or the educational standard alone,
+it is undoubtedly true that, on the whole, native ability, independence
+and energy are present to a higher degree in our well-to-do and prosperous
+families than in the stocks which merely hold their own or which
+gradually decline, and there is no gainsaying the fact that in so far as
+the lower classes are where they are through actual deficiency--and there
+are enormous numbers in this category--they threaten our very existence as
+a race. It is imperative that the great middle class in particular
+establish in some way a selective birth-rate, by increased fertility on
+their own part, and diminished fecundity on the part of inferior stocks,
+which will offset or more than offset the disproportionate increase of the
+socially unfit.
+
+=Four Children to Each Marriage Required to Maintain a Stock.--=It is
+estimated that under present conditions an average of at least four
+children should be born to each marriage if a stock is to maintain its
+numbers undiminished. Some of our most valuable strains are falling far
+short of this average. In a statistical table on the relative fertility of
+different stocks, prepared by Pearson, we find the mentally defective,
+criminal, deaf-mute and degenerate stocks heading the list with averages
+ranging from five to seven children per family, while the American
+graduate (based on Harvard statistics) and the English intellectual types
+average less than two children per marriage. While the death-rate is
+higher in the undesirable classes mentioned, it is by no means enough
+higher to compensate for the difference in birth-rates. Thus while certain
+very desirable types are not maintaining themselves genetically, other
+extremely undesirable ones are rapidly more than replacing themselves.
+Investigations made by Heron in London show that this condition as regards
+English desirables did not exist sixty years ago; then the richer a
+community was in professional men and well-to-do families, the higher was
+the birth-rate.
+
+=Factors Contributing to Low Birth-Rate in Desirable Strains.--=Most
+students of the subject believe that the fecundity of much of the best
+blood in our country has reached such a low ebb as to threaten the whole
+fabric of our commonwealth. How to correct this is the pressing problem to
+which no one has found a solution. However much one may deplore it the
+fact remains that always in the history of the civilized world with the
+rise of material conditions in any class of a population there has come an
+accompanying limitation of child-birth. Explain this as we may in modern
+times--whether as an awakened individualism which looks only to the
+immediate interest of the individual as against the ultimate interest of
+the race, or a desire for luxuries or for a better opportunity for smaller
+numbers of children, or as a determined effort of the wage earner to
+better his conditions, or to the feminist movement with its accompaniment
+of a greater personal freedom of married women and the recognition of the
+fact that marriage and child-bearing are often bars to employment, or to
+general increasing pressure of economic burdens--in brief whatever the
+cause or causes, there is no denying the fact of a diminishing birth-rate
+among our abler men and women. Moreover, no amount of coaxing, cajoling or
+dire prophecy seems to avail in altering the conditions. Various partial
+remedies, many of them of questionable practicability, have been proposed,
+but so far there has been no far-reaching effort made to put any of them
+into effect. It has been suggested that society return to the simple life
+so that our young folk may marry earlier and live more easily on limited
+means, but so far few volunteers have appeared to lead the procession.
+While there is no doubt that present economic conditions tend to penalize
+parenthood, the simple life will not return for the mere asking. It has
+been pointed out that the father is in unfair competition with the
+bachelor and is also unfairly taxed in comparison, and some would
+therefore tax unmarried men more heavily. Others would pay a direct bounty
+on reproduction, but it is probable that such rewards would merely
+stimulate families of the lower types to increased fruitfulness. And so
+one panacea after another may be weighed and found wanting.
+
+=The Educated Public Must Be Made to Realize the Situation.--=It seems
+probable that the most success will be met with through the slow and
+unspectacular methods of education. The necessity of the situation must be
+driven home so that it becomes part and parcel of the collective
+intelligence of the educated public. Different ideals of life will have to
+be established in the young. If knowledge of the facts of heredity is
+thoroughly disseminated among the people and ideals regarding parenthood
+are fostered, then much will have been accomplished by the psychic power
+of suggestion alone toward the end desired.
+
+=Utilization of Family Pride as a Basis for Constructive Eugenics.--=There
+are few more powerful incentives to make the best of one's abilities, or
+few greater deterrents from vice than family pride; and there is no
+reason why this same sentiment may not be aroused in behalf of unborn
+generations. The sentiment of caste or aristocracy in some form is well
+nigh universal in mankind. The family of Mr. A came over in the Mayflower
+and is therefore worlds above the family of Mr. B, who arrived fifty years
+later. Mr. X's income is $5,000 a year, Mr. Y's only $1,500. The poor
+family in the front suite of the tenement regards itself as far superior
+to the one in the rear. Among criminals the professional house-breaker
+feels himself to be of higher caste than the sneak-thief, and in turn is
+surpassed by the bank-burglar. Even in the insane asylum the feeling is
+rampant. With such a wide-spread tendency for a foundation the creation of
+a sentiment of eugenic aristocracy is by no means a visionary undertaking.
+
+=The Tendency for Like to Marry Like.--=Even now there is a decided though
+unconscious tendency for like to marry like and thus create particular
+strains. We have lines, for instance, which produce notably families of
+scholars, others which yield mainly statesmen, and still other strains of
+inventors, of financiers, of naval men, of soldiers, and of actors
+respectively. And there is little doubt that people, with the facts of
+inheritance of ability once before them, will be led to act more or less
+in accordance with their knowledge. On the other hand, due apparently to
+the same unconscious tendency for like to marry like, we find produced
+criminalistic, feeble-minded, deaf-mute and tubercular stocks. The first
+type of family is often termed _aristogenic_ and the second or defective
+type, _cacogenic_.
+
+=Public Opinion as an Incentive to Action.--=Much of our social conduct is
+the result of the pressure of public opinion, yet so accustomed are we to
+this that we ordinarily do not feel it as a hardship. There is little
+doubt that similarly the more wholesome attitude toward parenthood
+advocated by the eugenist would be taken as a matter of course, once the
+idea became prevalent. It would come to be one of those socially
+preconceived ideas which are as much actualities and which become
+unconscious guides to action no less certainly than do the more obvious
+personal habits of the individual. And just in the degree that we as a
+race get the "feeling" that intellect, morals and skill are highly
+desirable attributes in marriage selection, just in that degree will one's
+affections in their earlier stages gravitate toward individuals who
+possess such qualities in high degree. In the main, those stocks which
+have shown by ancestral as well as personal achievement their superiority
+will tend to insure most certainly a continuation of this superiority in
+offspring.
+
+=Choosing a Marriage Mate Means Choosing a Parent.--=Although marriages,
+as all young folks know, are made in Heaven, it is interesting to see what
+a vast number of these foreordained matches coincide with propinquity in
+college, in church, or in the same social set. Moreover, children are born
+here on earth. The one thing of all things that the eugenist desires is
+for these young folk to get a clear-eyed vision of the fact that in
+choosing a marriage mate they are also choosing the future father or
+mother of their children with all that this implies.
+
+=The Best Eugenic Marriage Also a Love Match.--=A few recent writers, who
+show an utter misconception of what the aim of modern eugenics is, have
+raised the cry of give us the old-fashioned love match instead of the
+eugenic marriage, as if the eugenist's ideal of moral cleanliness, freedom
+from transmissible physical taints or mental enfeeblement, and an attitude
+of special approval toward marriages which bring together individuals of
+more than average mental or spiritual endowment, had anything in it that
+was inimical to love. No one better than he realizes the sordid depths to
+which marital relations devoid of mutual affection and regard must reach.
+Certainly there is nothing in the eugenic ideal when its full import is
+understood that can shock the sensibilities of the most delicate-minded.
+Indeed it is people of fine susceptibilities who will be the first to feel
+repugnance toward a marriage which means mental or physical deterioration
+of their own blood.
+
+=Good Traits No Less Than Bad Ones Inherited.--=An inspection of such
+charts as those shown in Figs. 37, 38 and 39, pp. 313, 314, 316--and an
+abundance of such encouraging records may now be found--reassures us in
+our convictions that good traits are no less inheritable than bad ones.
+And what any healthy, mentally well-endowed person may be depriving the
+world of if he or she declines to enter into a fruitful marriage can not
+be better exemplified than in the following excerpt from Davenport:
+
+    "Many a man at the opening of his life work vows, as Judge John Lowell
+    of the middle of the eighteenth century did, as he was being graduated
+    from Harvard College, that he will never marry. But nature was too
+    strong for John Lowell and he married three times, and among his
+    descendants was the director of a great astronomical observatory, the
+    president of Harvard College, a principal founder and promoter of the
+    Massachusetts General Hospital and the Boston Atheneum; the founder of
+    the city of Lowell and its cotton mills; the founder of the Lowell
+    Institute at Boston; the beloved General Charles Russell Lowell and
+    his brother, James, both of whom fell in the Civil War, and James
+    Russell Lowell, poet, professor and ambassador; besides brilliant
+    lawyers and men entrusted with large interests as executors of
+    estates. Do you think John Lowell would have taken that vow could he
+    have foreseen the future?"
+
+
+[Illustration: FIG. 37
+
+Pedigree of family with artistic (dark upper section), literary (dark
+right section) and musical (dark left section) ability (from Davenport).]
+
+
+=The Elimination of the Grossly Unfit Urgent.--=But even if, under present
+conditions of partial knowledge and lack of an adequate standard, the
+constructive phase of eugenics must be left in the main to the awakening
+conscience of the individual as humanity improves in general
+enlightenment, the second phase, the elimination of the grossly unfit is
+one of the greatest social obligations that confronts us to-day. For if
+there is an alarming amount of mental impairment in civilized nations, and
+if the problems of pauperism, inebriety, prostitution and criminality are
+closely interwoven with the problems of mental unsoundness, as we have
+every reason to believe from available data, then any means which will
+operate toward securing normally functioning brains will at the same time
+operate toward diminishing, defects and delinquencies. And inasmuch as a
+considerable proportion of defects, both mental and physical, are
+inheritable, it is obvious that if we can diminish the number of children
+born into the world with defective brains or bodies we have made a long
+stride in the right direction.
+
+
+[Illustration: FIG. 38
+
+Inheritance of ability (from Kellicott after Whetham).]
+
+
+=Suggested Remedies.--=But how go about it? Various schemes have been
+proposed, of which the chief are as follows:
+
+    1. Laws restricting marriage.
+
+    2. Systems of mating with the purpose of covering up and gradually
+    diluting out defective traits.
+
+    3. Segregation during the reproductive period.
+
+    4. Sterilization.
+
+    5. Education in the principles of eugenics.
+
+=Inefficacy of Laws Which Forbid Marriage of Mental Defectives.--=The
+utter inefficacy of the first proposition, namely the enactment of laws
+restricting marriage, at least as regards the socially unfit whose
+condition is based on impaired mentality, has been demonstrated time and
+again. If they are forbidden marriage, they merely have children without
+getting married. Most states have laws to prevent the marriage of such
+individuals but these laws are almost wholly ineffective in preventing
+procreation on their part. We might as well recognize once for all that in
+such cases nothing short of close custodial care or sterilization will
+accomplish the end desired.
+
+As to the second proposition, systems of mating with the purpose of
+covering up and gradually diluting out defective traits, this has been
+shown to be possible with certain types of defectives. Whether it is
+desirable or not is a different question.
+
+
+[Illustration: FIG. 39
+
+Inheritance of ability (chart condensed and incomplete) in three markedly
+able families (from Kellicott after Whetham):
+
+1, Charles Darwin; 2, his cousin, Francis Galton, founder of the modern
+eugenic movement.]
+
+
+=Systems of Mating Impracticable in the Main.--=By systems of mating, it
+should be said, is not meant the arbitrary marrying of two individuals
+willy-nilly, but rather it is the prevention from marriage of two
+individuals having similar defects. In general the facts at our command
+indicate that in the majority of cases the offspring from a marriage of an
+insane, feeble-minded or epileptic person with a normal individual free
+from all neuropathic taints are normal or at most show but slight effects
+of the taint. But what normal individual would knowingly marry into such a
+stock? With few exceptions such traits where inheritable are apparently
+negative, that is, not represented by some positive abnormal factor but
+due to the lack of some element or elements necessary to the proper
+working of the normal brain. In the offspring of such a union the
+necessary missing factors are supplied by the normal parent. Or in
+Mendelian phraseology, the defective traits are recessive and are
+dominated by the normality of the other parent. Such offspring, however,
+while apparently normal of body are not normal of germ-plasm, inasmuch as
+half of their germ-cells will carry the abnormality of the defective
+parent as earlier explained (page 119) under Mendelism. We have already
+seen (page 119) how by continually marrying into strong strains the
+liability to recessive defect can be diluted out until the descendants are
+no more likely to have defective children than are members of our ordinary
+population. If, however, as is estimated in Bulletin No. 5 of the
+_Eugenics Record Office_, about thirty per cent. of our general population
+already carry recessive neuropathic taints, it certainly is a hazardous
+proceeding to attempt thus to breed out nervous defects unless one is
+absolutely sure of the normality of the strain into which it is proposed
+to marry. The great difficulty is in determining whether or not there is a
+defective ancestry in a given stock. We have at present no criteria for
+identifying normal individuals who have defective germ-plasm. As a
+practical test, however, if no defect has appeared in the stock for three
+or four generations back, the marriage would be relatively as safe as are
+the marriages of our average population to-day.
+
+=Corrective Mating Presupposes Knowledge of Eugenics.--=But such a scheme
+of corrective mating presupposes a relatively high degree of intelligence
+and judgment on the part of the participants, and this is just what we do
+not have and in the nature of things can not get, in the types of
+feeble-minded, epileptic and degenerate strains we are striving to
+eliminate. All our evidence shows that when unrestricted there is a marked
+tendency for feeble-minded to mate with feeble-minded, degenerate with
+degenerate. About sixteen per cent. of the feeble-minded, in fact, come
+from consanguineous marriages. If we try to legislate them into specific
+types of marriage then we encounter the same futility pointed out under
+our discussion of restrictive legislation, they will produce offspring
+without the formality of marriage.
+
+In certain cases of insanity and in other than neuropathic defects one can
+see how the system might be inaugurated with greater prospects of success,
+but even then a knowledge of the principles of eugenics would be necessary
+to the participants, or in other words we could only accomplish our end
+through our fifth proposition, education.
+
+=Segregation Has Many Advocates.--=As to the third proposition,
+segregation during the reproductive period, this seems to have a larger
+number of advocates than any other coercive measure. While on theoretical
+grounds it is plausible enough, when we face the actual putting of the
+method into practise we are confronted by the fact that tremendous sums of
+money would be required to sequestrate and maintain colonies or industrial
+refuges.
+
+When one realizes that no state now provides for more than a small
+minority of its defectives, and knowing also of the pressure that must be
+brought to bear on legislatures to secure sufficient funds to provide for
+these cases of extremest urgency, one can not be overly optimistic about
+the practicability of extensive sequestration.
+
+E. R. Johnstone, the superintendent of a large training school for
+feeble-minded in New Jersey, points out that no state in the Union is
+providing for many more than one-tenth of her feeble-minded and
+epileptics. If his estimate is true, to place in institutions, treat and
+train all its feeble-minded and epileptics would even now almost swamp any
+state treasury. But what _will_ it be in the future if we permit this
+unrestricted nine-tenths to go on and multiply their kind?
+
+Leaving out of account the enormous sums spent in private charities even
+now from one-fifth to one-seventh the total public expenditures of almost
+any one of our states is going to maintain its defectives, dependents and
+criminals. From the 1912 report of the secretary of state, in the state of
+Wisconsin, for instance, I learn that of the total expenses for 1912,
+sixteen per cent. was for charitable and penal institutions. The situation
+is even worse in some other states. Think of it! Think what a large total
+of expense it becomes! And the expense is far secondary from the
+humanitarian standpoint to the misery involved.
+
+In the _Survey_ of May 24, 1913, we find Mr. Hastings H. Hart, Director of
+the Department of Child Helping of the Russell Sage Foundation, proposing
+very specifically "a working program for the extinction of the defective
+delinquent," which involves segregation during the reproductive period. He
+gives the number of feeble-minded under public care as 20,000 in
+institutions for the feeble-minded, 16,000 in almshouses, 5,000 in
+hospitals for the insane, and 26,000 in prisons and reformatories, or a
+total of 67,000 already under custodial care. And he asserts that as
+nearly as can be judged, this is one-third of the feeble-minded persons in
+the United States.
+
+Between this estimate that one-third of our feeble-minded are in
+institutions and Doctor Johnstone's that we are not providing for many
+more than one-tenth of our feeble-minded and epileptic, there is a wide
+discrepancy, but I know of no accurate data[20] whereby the matter can be
+settled definitely. One point of difference may be that Doctor Johnstone
+specifically includes epileptics and another may be one of definition of
+feeble-minded. However, supposing that we could get them all into
+institutions, institutional care at present by no means also implies
+prevention of propagation. It is not an unusual history of feeble-minded
+women in our county poor-houses that they alternate between periods of
+housework in some family and periods of residence in the almshouse, the
+return to the latter being only too often to bear an additional child.
+
+Not a few students of the problem, however, advocate a rigid segregation
+as the only reasonable preventive measure, no matter what the expense.
+They point out that the cost is mounting up higher each year and that we
+are only increasing it ultimately by procrastination. They urge, moreover,
+that when counting the cost of the segregation of the feeble-minded we
+should bear in mind also that we are reducing the expenses of our other
+charity and penal institutions, since much of degeneracy, pauperism and
+petty criminality centers in mental enfeeblement. Some believe that
+colonies can be established which are in considerable measure
+self-supporting. Doctor Johnstone, for instance, although his estimates of
+the number of feeble-minded and epileptic is one of the highest, sketches
+out in a recent paper (in _Pediatrics_, August, 1912) a plan which he
+considers feasible.
+
+But what assurance have we that we can prevent the production of
+defectives by segregation? In reply may be cited a recent experiment on an
+extensive scale. Cretinism is a condition due to disease of the thyroid
+glands. It is characterized by goiter, marked deformities and imbecility.
+It is hereditary and has been very prevalent in certain valleys of
+southern Switzerland and northern Italy. Cretin mated with cretin and
+consequently a large new supply was constantly produced. In recent years
+in certain communities the sexes have been segregated (see _Eugenic
+Review_, 1910, Jordan) with the result that in such places cretinism has
+about disappeared.
+
+Coming now to the fourth solution proposed, namely, sterilization,[21] let
+us consider some of its alleged advantages and disadvantages.
+
+=Sterilization.--=First of all, since there is some considerable popular
+misunderstanding on the subject, it should be made plain that by
+sterilization is not necessarily, nor in fact generally, meant
+asexualization, or the removal of the reproductive glands. On the
+contrary, in the male, sterilization is ordinarily accomplished by an
+operation known as _vasectomy_, in which a small piece of each sperm duct
+is removed. Such reports on it as I have found indicate that it is a
+comparatively simple minor operation which involves no special
+inconvenience or hardship on the subject beyond the deprivation of
+offspring. In fact, according to Doctor Sharp's report, in the majority of
+cases where it has been put into practise the patient has usually
+submitted voluntarily after having the details of the situation explained
+to him and has often advised fellow delinquents to do likewise.
+
+Even should later developments show that a mistake had been made, in all
+probability the matter could be remedied by a second operation in which
+the cut ends of the ducts can be reunited. This has been accomplished
+experimentally in dogs, and furthermore, in men rendered sterile by
+occlusion of the duct through inflammatory diseases, the sterility has
+been remedied by removing the blocked area and reuniting the ends of the
+duct on either side.
+
+In women the corresponding operation--a section of the oviduct--is termed
+_salpingectomy_. Here, however, the operation is a more serious one as it
+usually involves opening the abdominal cavity and the accompanying hazard
+of infection, a danger sufficiently great that it is safe to say that the
+operation will be resorted to more rarely than vasectomy in man.
+
+=As a Eugenic Measure.--=Sterilization as a eugenic measure has many
+advocates and perhaps more opponents; and among the latter, it must be
+said, are many competent and thoughtful students of the subject who
+recognize existing conditions and deplore their continuance as much as any
+one. They maintain that while we may have to come to it as a last resort,
+we are yet too ignorant of the actual effects of the operation, or are too
+little informed on the inheritability of the specific traits we are trying
+to eradicate, to launch forth on so radical a program. We must not forget
+that when we put sterilization into effect we are going to have to deal
+with individual cases, not general averages.
+
+=To What Conditions Applicable.--=And just here, it seems to me, is the
+crux of the situation. When confronted by the defective individual, in a
+practical case, just what criteria are we going to use to determine
+whether this particular individual should be sterilized or not? Nearly all
+of the twelve states which have sterilization laws specify insanity,
+feeble-mindedness, epilepsy and criminality.
+
+=In Insanity.--=When it comes to insanity I strongly suspect that those
+who have the selection of the examining board will have difficulty in
+finding an alienist who is willing to take the responsibility of deciding
+on just which insane individuals shall be operated on and which not. For
+among the insane there are so many kinds and degrees of mental
+unsoundness, and these are of such varying and as yet unknown eugenical
+significance, that a positive decision is frequently out of the question.
+Of the twenty-seven or more recognized forms of insanity who knows with
+any considerable degree of certainty which are heritable, which not? Shall
+we treat all manic-depressives alike? Shall we treat them as, for
+instance, we would those suffering from dementia precox? Who will take the
+responsibility of answering positively? Again, what shall we do in cases
+of paresis, or general paralysis of the insane, an affliction which
+probably invariably has syphilis as its antecedent? Yet it constitutes one
+of the commonest forms of insanity found in asylums. Doctor George H.
+Kirby, director of Clinical Psychiatry, Manhattan State Hospital, says
+that with one exception there are more admissions of paretics to Manhattan
+State Hospital than sufferers from any other form of mental disorder. He
+continues, "We find that when either the father or the mother suffers from
+paresis that many other members of the family may be infected with
+syphilis, and furthermore, we find that a surprisingly large number of
+children in these families are feeble-minded, nervous, or in other ways
+abnormal." But here, it is clear, the patient has done the damage before
+he reached the hospital, nor was it paresis as such that did the harm but
+the syphilitic infection of which paresis itself was but the outcome.
+
+Certainly the one fact which stands out conspicuously when we face most
+concrete cases, is that at present we need more urgently than
+sterilization laws for the insane, exhaustive studies of the
+inheritability of specific mental infirmities that we may know with some
+degree of certainty which warrant sterilization.
+
+Yet on the other hand one of the most disquieting facts that confronts us
+to-day is the large number of patients who are on parole from our
+hospitals for the insane, subject to recall. What shall we do with them?
+Shall we submit them to the tremendous hardship of still remaining under
+custodial care although to all intents and purposes sane, or shall we make
+their release contingent upon their submission to vasectomy or
+salpingectomy?
+
+In a few cases such as Huntington's chorea (Figs. 26, 27, pp. 114, 115) we
+can proceed with a fair degree of assurance, for we know that this
+dreadful malady is transmitted as a positive trait and that in all
+probability half of the children of an afflicted individual will inherit
+the defect. Such patients, if they ever rally sufficiently temporarily to
+leave the hospital, or where encountered outside the hospital should
+certainly be restrained from procreation. It is questionable if even their
+children, though apparently normal, should be allowed to have offspring,
+for usually the disorder does not manifest itself until middle life and
+then it is too late to try to prevent its transmission since the affected
+individual has already probably married and had children. But Huntington's
+chorea is a comparatively rare form of insanity, and one of only a few
+about which our knowledge as regards its transmissibility is fairly
+satisfactory.
+
+=In Feeble-Mindedness.--=When we come to institutions for the
+feeble-minded, however, there seems to be much more unanimity of opinion
+among physicians in charge of such institutions that sterilization would
+be an effective and satisfactory disposition to make of many cases, if we
+are to release the patients in question from custody. Unquestionably in
+cases of imbecility it is easier than in insanities to pass conclusive
+judgment on the inheritability of the condition in a large class of cases.
+Practically all are agreed that either permanent custodial care through
+the reproductive period or sterilization should be enforced. Some maintain
+that such individuals should remain permanently in institutions anyway and
+that therefore to sterilize them is needless, while others urge that if
+sterilized many capable of making their own living could be freed and
+allowed to do so.
+
+According to Goddard the feeble-minded woman is about three times as
+likely to find a mate as a feeble-minded man, hence it would seem to be of
+much greater importance to sterilize the woman than the man.
+
+Again it might be urged with much justification, that even though
+sterilized, the feeble-minded individual because of lack of self-control
+will transgress sexually and will thus certainly become a menace to
+society in the spread of venereal diseases. If Mr. Hart's estimate is
+anywhere near correct, that there are 60,000 feeble-minded women in the
+United States of child-bearing age, and that 13,000 are already in
+custody, then the task of getting all women of this class into custody is
+not so insurmountable as would at first appear.
+
+=In Cases of Epilepsy.--=As to epilepsy, I find a very decided difference
+of opinion among physicians. Some consider it, on account of its
+apparently strong inheritability, together with the shocking crimes
+perpetrated by epileptic criminal types, one of the most serious menaces,
+while others point out that we know nothing of the real cause of epilepsy,
+that there are all degrees and shades, that it is probably referable to
+different causes in different cases and that no one is able to say what
+the offspring of any given epileptic will be.
+
+As to criminal types, here again we face the difficulty of deciding any
+particular case. Let us suppose that twenty-five per cent. of criminals
+are mental defectives, how shall we sift them out from the seventy-five
+per cent. who are supposed to be eugenically normal? Doubtless in many of
+the twenty-five per cent. class, the indications of defective mentality
+are sufficiently evident to prevent mistakes, but a considerable number of
+uncertain status must also remain near the border-line.
+
+=Sterilization Laws.--=Although twelve of our states already have
+sterilization laws, only two, Indiana and California, seem to have made
+any active attempt to enforce them. The situation is too new yet in
+Wisconsin, Michigan and Pennsylvania for these states to have shown what
+they intend to do. Although the Indiana law says, "it shall be compulsory
+for each and every institution" to maintain the practise, it has fallen
+into disuse since 1911, presumably because the governor believed the law
+unconstitutional. It is of interest to see the motive underlying the law
+in various states. In the majority it is purely eugenic. In Connecticut it
+is mainly eugenic though partly therapeutic. In California it is
+apparently in part therapeutic, since it is stated as being for the
+physical, mental or moral benefit of inmates of various state
+institutions, and in part punitive and eugenic, since individuals twice
+committed for sexual offenses or three times for other crimes are subject
+to the operation.
+
+In Washington and Nevada the object is purely punitive, the persons
+specified being habitual criminals and persons adjudged guilty of carnal
+abuse of female persons under ten years of age, or of rape. In these
+states also the court orders the operation instead of leaving it to the
+decision of a board of medical experts.
+
+=Social Dangers in Vasectomy.--=It has been urged against vasectomy that
+it will work untold harm because it relieves of the responsibility of a
+probable parentage. This argument does not appeal to one as very weighty
+as far as the imbecile or other degenerate is concerned, because one of
+the very traits characteristic of such individuals is lack of any sense of
+responsibility. By this same token, however, we have a very good argument
+for sequestration as against sterilization, for the degenerate, even
+though sterilized, will not be restrained sexually and will be likely to
+disseminate venereal diseases or commit rape. Furthermore, there will be
+the temptation to sterilize and liberate certain types that would
+otherwise have been kept permanently in custody.
+
+=Our Present Knowledge Insufficient.--=When all is said and done, after we
+take into account the meagerness of our present knowledge on the subject,
+it is not to be wondered at that many thoughtful students of a
+conservative turn of mind, feel that any considerable practise of
+sterilization is premature. The problem has so many phases, and despite
+occasional bits of positive knowledge, we are yet in such a sea of
+ignorance regarding it, that in no field is the good Friar Laurence's
+admonition of "wisely and slow; they stumble that run fast," needed more
+at present than it is here.
+
+There is little doubt that in theory the feeble-minded and similar
+defectives should be sent to institutions and kept there, but the
+important practical question is, can this be done? We can have no final
+answer until it is tried. While the initial expense would undoubtedly be
+great, if we could keep our defectives from propagation for a single
+generation we could very materially lessen their numbers and in succeeding
+generations the expenses of their care would rapidly diminish.
+
+The one crying need that stands out most prominently in this whole field
+is that of careful investigation of individual cases and specific types of
+malady, together with an accurate census of conditions as a whole. Our
+knowledge of individual malign heredities is too meager to carry us very
+far at present. When we have found after adequate investigation in just
+which specific types of defects heredity is an important factor--and we
+shall undoubtedly find it to be one in many cases--then we can proceed
+confidently with sterilization, if it will prove to be more practical and
+desirable than sequestration.
+
+=Sterilization Laws on Trial.--=It will be of great interest and
+instruction to see how extensively, in the various states which have
+recently passed sterilization laws, the experts selected will find it
+expedient to carry on sterilization, and what criteria they will use in
+deciding on individual cases. That sterilization can be put into effect is
+indisputable, as may be seen from the fact that several hundred operations
+have been performed in Indiana. If the board on whom the decision depends
+happens to be one which feels that many people are likely to distress
+themselves unduly over the border-line cases, and overlook the fact that
+there is always a goodly residue with which to proceed without great risk
+of mistake, then we may expect to see a vigorous campaign inaugurated, and
+those of us who are still undecided in the matter will have an opportunity
+of learning more certainly the merits or the failings of the scheme.
+
+Certain married degenerate types would seem to be the ones most urgently
+demanding attention. Having already begotten several defective children
+and with nothing else in prospect but the production of the same kind, it
+is difficult to see from any standpoint why a vasectomy on the male would
+not be a merciful act. There are not a few such families where the father
+is periodically in the hands of the law and yet not in permanent
+restraint. Once in custody his release could be made contingent on
+vasectomy.
+
+=An Educated Public Sentiment the Most Valuable Eugenic Agent.--=Coming
+now to the last proposition, education of the public in the principles of
+eugenics, this is the method calculated to be of more far-reaching service
+than any other, in the negative as well as in the positive phases of
+eugenics. Education is necessary before we can have effective restrictive
+measures for the mentally incompetent established and enforced, and it is
+also a prerequisite to intelligent procedure on the part of normal
+individuals in considering their own fitness for marriage.
+
+Of greatest importance in preventing undesirable marriages, as far as
+people of normal intelligence is concerned, will be the sentiment of
+disapproval which will arise on the part of society itself when it becomes
+really convinced that certain marriages are inimical to social welfare.
+Public opinion is, in fact, one of the most potent influences in marital
+affairs, simply because refusal to abide by the dictates of the community
+means social ostracism.
+
+That social disapproval of certain unions can become a very real factor in
+preventing such marriage is evinced on all sides by the numerous barriers
+to marriage already in existence based on race, religious sect or social
+status. Even in our much vaunted democracies one is looked down on who
+marries "beneath" his or her social set. This sentiment of taboo, so
+readily and often so senselessly cultivated in our present human society,
+will inevitably spring up in consequence of a wide-spread knowledge of the
+facts of human heredity. It is to such a growth, to the establishment of a
+disapproval which is the product of its own sentiments rather than to
+legislative enactments, that society must look for the greatest
+furtherance of the eugenic program.
+
+Necessary as legal restraint is in certain cases, it must obviously be
+restricted to only the most glaring defects. Moreover, legislation can not
+run far in advance of public opinion.
+
+=The Question of Personal Liberty.--=It must be admitted that there is a
+reluctance on the part of many even thoughtful individuals to the
+application of methods which savor in any way of restraint. An objection
+not infrequently urged by such persons against the application of certain
+eugenic principles is that they demand an unwarranted curtailment of
+personal liberty.
+
+To those who hoist the flag of personal liberty, it may fairly be asked,
+how much personal liberty does the syphilitic accord his doomed and
+suffering wife and children, or how much personal liberty is the portion
+of the offspring of feeble-minded parents? Or, what quota of personal
+liberty will accrue to the ill-fated descendants of the epileptic, the
+habitual drunkard or criminal, the gross moral pervert, the congenially
+deaf and dumb, or to even the progeny which may result from the union of
+two well-established tubercular strains?
+
+We do not hesitate to send the pick of our stalwart healthy manhood to war
+to be slaughtered by the thousands and tens of thousands when an affront
+is offered to an abstraction which we term our national honor, and,
+sublimely unconscious of the irony of it all, we throw ourselves into a
+well-nigh hysterical frenzy of protest when it is proposed to stop the
+breeding of defectives by infringing to a certain extent on their personal
+liberties.
+
+Society has already found it necessary to suppress certain individuals
+and yet we hear little complaint about loss of personal liberty in such
+cases. But if it is necessary to restrain the man who would steal a purse
+or a horse, is it not still more urgent to restrain one who would poison
+the blood of a whole family or even of an entire stock for generations?
+Surely there can be but one answer; society owes it to itself as a matter
+of self-preservation to enforce the restraint of persons infected with
+certain types of disease and of individuals possessing highly undesirable
+inheritable traits, so that perpetuation of such defects is impossible.
+
+=Education of Women in Eugenics Needed.--=One of the most crying needs of
+the present is the awakening and educating of women to the significance of
+the known facts. For they are perhaps the greatest sufferers, and once
+informed, as a mere matter of safety if for no other reason, they will see
+the necessity of demanding a clean bill of health on the part of their
+prospective mates. Furthermore in the last analysis woman is the decisive
+factor in race betterment, for it is she who says the final yea or nay
+which decides marriage and thus determines in large measure the qualities
+which will be possessed by her children. Above all, young women must come
+to realize that the fast or dissipated young man, no matter how
+interestingly or romantically he may be depicted by the writer of fiction,
+is in reality unsound physically, and is an actual and serious danger to
+his future wife and children.
+
+=Much Yet to Be Done.--=But plain as is our duty regarding the application
+of facts already known, when we consider that the student of heredity has
+made only a beginning, it is equally evident that he must be urged on in
+his quest for new facts, and the establishment of new principles. There is
+imperative need to carry on proper experiments with plants and animals, to
+collect necessary data regarding man, and for what is scarcely less
+important, the publication of the facts already acquired so that the
+public may be guided aright.
+
+Just at present it is of the utmost importance to secure more trustworthy
+statistics in order that we may intelligently go about instituting
+suitable restrictive measures for undesirable human strains. We must know
+the exact number and kinds of feeble-minded, epileptic and insane in our
+population, and we must have more insight into the personal status and
+pedigrees of our delinquents and criminals. For purposes of rational
+procedure such information is indispensable. Much can be done by
+hospitals, "homes" and penal institutions by determining and recording
+more accurately all obtainable facts regarding the ancestry of their
+charges. Moreover, in such states as Wisconsin, where the state hospitals
+for the insane have each an "after-care-agent," the duties of such
+officers might well include the collection of more adequate data regarding
+the hereditary aspects of their patient's condition. And lastly, if in
+every census, whether state or national, it were made an important part of
+the work to secure accurate vital statistics, particularly as they pertain
+to human heredity, the contribution toward enabling us ultimately to
+purge the blood of our nation of certain forms of suffering, degeneracy
+and crime would be inestimably great.
+
+=A Working Program.--=And now after reviewing at some length various
+aspects of man's hereditary and congenital endowment, the important
+question arises as to whether it is possible, with the knowledge at
+present available, to go ahead with a practical program which will insure
+to the child of the future its right of rights, that of _being well-born_.
+When one considers the matter it is evident that much can be done at once.
+Most of the needs set forth in the preceding paragraph can clearly be met
+in a fair degree by instituting the procedures indicated.
+
+One of the obvious duties in a restrictive way that confronts us right at
+the start is the care and control of the feeble-minded and of the
+defective delinquent in such a way as to prevent procreation. Much help
+can be given also through intelligent agitation for the establishment of
+colonies for epileptics and the higher grades of feeble-minded which can
+be made in considerable measure self-supporting. A given colony must, of
+course, be for one sex alone. Much can be done, furthermore, by putting
+into operation, both in and out of institutions, effective systems of
+registering births and deaths together with accompanying facts which may
+prove of eugenical significance.
+
+Again, we should more surely identify and exclude undesirable immigrants
+and also undertake thoroughgoing investigations to determine which races
+we can not profitably assimilate into our own blood.
+
+Physicians should pay more attention to the hereditary and congenital
+aspects of their cases and make it more a matter of conscience than they
+do at present to advise patients with regard to marriage. Prenuptial
+medical inspection should become the custom, if not by law at least as a
+voluntary procedure. Every parent must come to realize the grave risk to
+which he is subjecting his daughter if a guarantee of physical fitness,
+even more than assurance of financial standing or social position, is not
+forthcoming from her prospective mate.
+
+Wholly apart from the field of heredity though in a realm intimately
+concerned with the birthright of the child, much practical good can be
+accomplished by pondering the facts and the fictions of prenatal influence
+and in the light of the knowledge thus gained, seeing that while foolish
+and unnecessary worries are abolished, the conditions of health, nutrition
+and occupation surrounding the expectant mother are the best obtainable.
+It is the sacred duty of every individual, moreover, to see that the
+maximal possibilities of his own germ-plasm are not lowered by vicious or
+unwholesome living.
+
+As individuals we can cultivate a greater sense of responsibility
+regarding marriage and parenthood in those for whose training we are
+responsible. We can study this whole subject conscientiously, keep pace
+with new knowledge and see that other people are likewise informed. In
+showing an enlightened interest in the ideals of eugenics and a
+sympathetic approval of wholesome marriages, a sentiment toward parenthood
+will gradually arise which will make it seem more desirable to many worthy
+people than it does at present. If we are of good stock ourselves we
+should recognize that it is highly desirable that we give to the race at
+least four children. On the other hand, if we come from a strain which is
+eugenically undesirable we should with equal conscientiousness refrain
+from contributing to human misery. For where serious obstacles to a union
+exist, renunciation is certainly a higher manifestation of love than is
+consummation of a marriage which will result in untold misery to the
+object of the affections. As a matter of fact, with adequate preliminary
+knowledge as to what actually constitutes a serious drawback to marriage,
+where such really exists and is recognized by the associated individuals,
+love of the kind that leads to marriage is not likely to arise.
+
+As has been suggested by various students of eugenics, it is even at
+present perhaps not infeasible for earnest individuals to start in a quiet
+way local centers for the keeping and filing of accurate records of their
+family traits for the future use of their descendants. Such groups,
+voluntary though they be, would soon acquire a degree of distinction that
+would make other people of good endowments wish to join in and go on
+record as eugenically desirable.
+
+Lastly, it should not be forgotten that good traits are inherited as
+certainly as bad ones. Moreover, in the realm of human conduct, even
+though the fundamental features of behavior are based on an inherited
+organization, man is not always driven by an inexorable linkage of
+inherited neutral units into only one line of conduct, since more or less
+capacity for alternative action is also inherited. It is the personal
+duty of every member of society to aid in affording the opportunity and
+providing the proper stimuli to insure that out of the many possibilities
+of behavior which exist in the young at birth, those forms are realized
+which are best worth while to the individual and to society. And while we
+recognize that improved environment alone can not correct human
+deficiencies we must nevertheless not relax our efforts to get cleaner
+foods, cleaner surroundings, cleaner politics and cleaner hearts.
+
+Why go on alleviating various kinds of misery that might equally well be
+prevented? When one squarely faces the issue, surely the absurdity of our
+present practises can not but be evident to even the most thoughtless.
+
+=Which Shall It Be?--=As a matter of social evolution, human homes
+originated in the necessity of an abiding place for the nurture and
+training of the young past their first period of helplessness. Well in the
+foreground of the mental picture which arises when we hear the very word
+_home_, are children. What shall the home of the future be with regard to
+its most important assets, the children? Shall we as a people continue to
+be confronted at every turn by the dull countenance of the imbecile, the
+inevitable product of a bad parental mating; or the feeble body and the
+clouded intellect of the child sprung from a parentage of polluted blood;
+or the furtive cunning of the born criminal, the will-less mind of the
+bred degenerate, or the shiftless spawn of the pauper? Or shall it be a
+type with laughing face, with bounding muscles, with unclouded brain,
+overflowing with health and happiness--in short, _the well-born child_?
+
+The answer is in our own hands. The fate of many future generations is
+ours to determine and we are false to our trusteeship if we evade the
+responsibility clearly laid before us. How conscientiously we heed known
+facts, how actively we acquaint ourselves with new facts, and how
+effectively we execute the obvious duties demanded by these facts, will
+give us the answer.
+
+
+THE END
+
+
+
+
+GLOSSARY
+
+
+ACQUIRED CHARACTERS, traits developed in the body through changes in
+environment or function, in contra-distinction to those which have their
+specific causes in the germ-cells.
+
+ADAPTATION (L. _ad_, to; _aptus_, fit), fitness to environment.
+
+ALBINISM (L. _albus_, white), a condition of deficiency in pigment.
+
+ALLELOMORPH (Gr. _allelon_, of one another; _morphe_, form), one of a pair
+of alternate Mendelian characters.
+
+AMEBA (Gr. _amoibe_, change), a primitive single-celled animal.
+
+AMPHIBIAN (Gr. _amphi_, both; _bios_, life), capable of living both on
+land and in water.
+
+ANTHROPOID (Gr. _anthropos_, man; _eidos_, form), man-like.
+
+ARISTOGENIC (Gr. _aristos_, best; _genesis_, origin), pertaining to the
+genetically most desirable human strains.
+
+ASSOCIATION AREAS, those regions of the brain in which presumably the
+higher mental processes are effected.
+
+ATAVISM (L. _ad_, before; _avus_, grandfather), a return in one or more
+characters to an ancestral type. See p. 8 for restricted modern usage.
+
+ATROPHY (Gr. _a_, negative; _trophe_, nourishment), a wasting away of a
+part of a living organism.
+
+AXON (Gr. _axon_, axis), the process from a nerve cell which becomes a
+nerve fiber.
+
+BINET-SIMON SCALE, a series of tests graded to age and previous training
+of the average normal child, much used in measuring mental deficiency.
+
+BIOLOGY (Gr. _bios_, life; _logos_, discourse), the study of life and of
+living things.
+
+BIOMETRY (Gr. _bios_, life; _metron_, measure), the study of biological
+problems by means of statistical methods.
+
+BLASTOMERE (Gr. _blastos_, germ; _meros_, part), one of the early cells
+formed by the division of the ovum.
+
+BLASTOPHTHORIA (Gr. _blastos_, germ; _phtheiro_, destroy), deterioration
+of the germ as the result of direct pathogenic or other disturbing agents.
+
+BLENDING INHERITANCE, inheritance in which the characters of the parents
+seem to blend in the offspring.
+
+CACOGENIC (Gr. _kakos_, bad; _genesis_, origin), pertaining to genetically
+undesirable human strains.
+
+CELL, the fundamental unit of structure in plants and animals.
+
+CENTROSOME (Gr. _kentron_, center; _soma_, body), a small body which
+functions in indirect cell-division.
+
+CHARACTER, any distinguishing feature, trait or property of an organism.
+
+CHEMOTROPISM (chemical and tropism), defined, p. 198.
+
+CHROMATIN (Gr. _chroma_, color), deeply staining substance of the
+cell-nucleus.
+
+CHROMOSOMES (Gr. _chroma_, color; _soma_, body), characteristic deeply
+staining bodies, typically constant in number and appearance in each
+species of animal or plant, which appear in the cell during indirect
+division.
+
+CHROMOTROPISM (Gr. _chroma_, color; _trope_, turning), defined, p. 198.
+
+CLEAVAGE, the division of the egg-cell into many cells.
+
+CONGENITAL (L. _con_, together; _gigno_, bear), present at birth.
+
+CONJUGATION (L. _con_, together; _jugum_, yolk), the union of germ-cells
+or unicellular individuals for reproduction.
+
+CONSTRUCTIVE (or positive) EUGENICS, a system of securing a superior race
+through propagation of the fittest individuals.
+
+CORTEX (L. _cortex_, bark), the outer or investing layer of the brain.
+
+CYTOPLASM (Gr. _kytos_, cell; _plasso_, form), the protoplasm of the cell
+outside of the nucleus.
+
+DALTONISM, the commonest form of color-blindness in which the affected
+individual is unable to discriminate between red and green.
+
+DENDRITES (Gr. _dendron_, tree), branching processes which spring from
+nerve-cells.
+
+DETERMINER (L. _determinare_, to determine), the distinctive cause or unit
+in a germ-cell which determines the development of a particular character
+in the individual derived from that cell. The terms _gene_ and _factor_
+are sometimes used as synonyms of determiner.
+
+DIHYBRIDS (L. _di_, two; _hybrida_, mongrel), the offspring of parents
+differing in two characters.
+
+DIPLOID (Gr. _diploos_, double; _eidos_, form), the dual or somatic number
+of chromosomes.
+
+DOMINANT CHARACTER (L. _dominare_, to be a master), a character from one
+parent which manifests itself in offspring to the exclusion of a
+contrasted character from the other parent.
+
+DROSOPHILA, a genus of fruit-flies of which there are several species.
+
+DUPLEX (L. _duo_, two; _plico_, fold), the condition in which a character
+is represented by two determiners, one from each parent.
+
+ELECTROTROPISM (Gr. _electron_, amber; _trope_, turning), defined, p. 198.
+
+EMBRYO (Gr. _embryon_), the young organism in its earliest stages of
+development.
+
+EMBRYOGENY (Gr. _embryon_; _genesis_, generation), the development of the
+embryo.
+
+EUGENICS (Gr. _eugenes_, well-born), the science relating to improvement
+of the human race through good breeding.
+
+FACTOR, the determiner of a particular hereditary character.
+
+FEEBLE-MINDEDNESS, deficiency in mental development. For grades, see p.
+244.
+
+FERTILIZATION, union of the sexual cells.
+
+FETUS (L. _feuere_, to bring forth), the unborn young animal in its later
+(after the second month in man) stages of development.
+
+FLAGELLUM (L. _flagellum_, little whip), a vibratile, thread-like organ of
+locomotion.
+
+GAMETE (Gr. _gamos_, marriage), a mature germ-cell.
+
+GENETICS (Gr. _genesis_, origin), the science which deals with heredity
+and the origin of individuals in general.
+
+GENOTYPE (Gr. _genea_, race; _typto_, strike), the germinal constitution
+of an organism.
+
+GEOTROPISM (Gr. _ge_, earth; _trope_, turning), defined, p. 198.
+
+GERM-CELL, a reproductive cell.
+
+GERMINAL VARIATIONS, variations which owe their origin to some
+modification in the germ-cells.
+
+GERM-PLASM, the material basis of inheritance.
+
+GONAD (Gr. _gonos_, generation), a germ-gland.
+
+HAPLOID (Gr. _haploos_, single; _eidos_, form), the single or reduced
+number of chromosomes as found, for instance, in the mature germ-cells.
+
+HELIOTROPISM (Gr. _helios_, sun; _trope_, turning), defined, p. 198.
+
+HEREDITY (L. _heres_, heir), resemblance of individuals to their
+progenitors based on community of origin.
+
+HERITAGE (L. _heres_, heir), all that is inherited by an individual.
+
+HETEROZYGOTE (Gr. _heteros_, other; _zygon_, yolk), an individual produced
+through the union of germ-cells which are unlike in one or more
+determiners. Adjective, _heterozygous_.
+
+HOMOZYGOTE (Gr. _homos_, same; _zygon_, yolk), an individual produced
+through the union of germ-cells which are alike in determiners. Adjective,
+_homozygous_.
+
+HYBRID (L. _hybrida_, mongrel), the offspring of parents which differ in
+one or more characters.
+
+IDENTICAL TWINS, twins which show identical inborn characters, both having
+come presumably from the same ovum.
+
+IDIOT (Gr. _idios_, peculiar, private), defined, p. 244.
+
+IMBECILE (L. _imbecillis_, weak), defined, p. 244.
+
+INHERITANCE (L. _in_, in; _heres_, heir), the sum of all characters which
+are transmitted by the germ-cells from generation to generation.
+
+INHIBITOR (L. _in_, in; _habeo_, hold, have), that which checks or
+restrains.
+
+INSTINCT (L. _in_, in; _stingno_, prick), defined, p. 203.
+
+INTRA-UTERINE (L. _intra_, within; _uterus_, the womb), within the womb.
+
+IRRITABILITY (L. _irrito_, excite), the property of responding to stimuli.
+
+LININ (L. _linum_, flax), filaments of the cell-nucleus not readily
+stained by dyes.
+
+LUETIN TEST (L. _lues_, pest), a test for syphilis; see p. 188.
+
+MAMMALS (L. _mamma_, breast), warm-blooded, hairy animals which suckle
+their young.
+
+MATURATION (L. _maturus_, ripe), the final stages in the development of
+the sex-cells characterized by two divisions in one of which the number of
+chromosomes is reduced by one-half.
+
+MENDELIAN, MENDELISM, referring to Mendel, the founder of a theory of
+heredity. See p. 67.
+
+METAZOA (Gr. _meta_, over; _zoon_, animal), all animals higher than the
+protozoa.
+
+MITOSIS (Gr. _mitos_, thread), indirect nuclear division, characterized by
+the appearance of a fibrous spindle and a definite number of chromosomes.
+The latter split to form daughter chromosomes which diverge to the poles
+of the spindle to form parts of the new nuclei.
+
+MONGOLIAN, a type of feeble-minded individual, see p. 248.
+
+MONOHYBRID (Gr. _monos_, single; L. _hybrida_, mongrel), the offspring of
+parents, differing in one character.
+
+MORON (Gr. _moros_, foolish), defined, p. 244.
+
+MUTATIONS (L. _mutare_, to change), abrupt, inheritable germinal
+variations. Frequently though not necessarily they are changes of
+considerable extent.
+
+NEURAL (Gr. _neuron_, nerve), pertaining to the nervous system.
+
+NEURON (Gr. _neuron_, nerve), a nerve-unit consisting of a nerve-cell with
+branching processes called dendrites and an axon or axis cylinder process
+which gives rise to a nerve fiber.
+
+NEUROPATHIC (Gr. _neuron_, nerve; _pathos_, suffering), relating to
+disease of the nervous system.
+
+NUCLEOLUS (L. dim. of nucleus), a well-defined body found within the
+nucleus of a cell.
+
+NUCLEUS (L. _nux_, a nut), the central organ of a cell.
+
+NULLIPLEX (L. _nullus_, not any; _plico_, fold), the condition in which no
+determiners of a given character exist in a particular individual.
+
+OÖCYTE (Gr. _oon_, egg; _kytos_, cell), the ovarian egg in one stage of
+development.
+
+OÖGENESIS (Gr. _oon_, egg; _genesis_, origin), the development of ova from
+primitive sex-cells.
+
+OÖGONIUM (Gr. _oon_, egg; _gonos_, generation), a primordial egg-cell.
+
+OVARY (L. _ovum_, egg), the organ in which the egg-cells multiply and are
+nourished.
+
+OVUM (L. _ovum_, an egg), the female sex cell.
+
+PARTHENOGENESIS (Gr. _parthenos_, virgin; _genesis_, origin), development
+of an egg which has not united with a male gamete.
+
+PHENOTYPE (Gr. _phaino_, show; _typto_, strike), the existing type of
+individual irrespective of hereditary possibilities which may reside in it
+undeveloped.
+
+PHOTOTROPISM (Gr. _phos_, light; _trope_, turning), defined, p. 198.
+
+PLACENTA (L. _placenta_, a flat cake), the organ by which the fetus of the
+higher mammals is attached to the uterine wall of the mother for purposes
+of nourishment, respiration and excretion. In it the maternal and fetal
+blood, although not intermingling, are brought into such close proximity
+that an interchange of dissolved substances is possible.
+
+POLAR BODIES, the minute cells which are separated from the egg in its
+maturation divisions.
+
+PRIMATE (L. _primus_, first), the highest order of animals, including
+monkeys, apes and man.
+
+PRONUCLEUS, the nucleus of the mature ovum or sperm-cell.
+
+PROTOPLASM (Gr. _protos_, first; _plasma_, form), the essential living
+substance.
+
+PROTOZOA (Gr. _protos_, first; _zoon_, animal), single-celled animals or
+animals composed of cells not separable into different tissues.
+
+PSYCHICAL (Gr. _psyche_, the soul), pertaining to the mind.
+
+RECESSIVE CHARACTER (L. _recessus_, a going back), a character from one
+parent which remains undeveloped in offspring when associated with the
+corresponding dominant character from the other parent.
+
+REDUCTION DIVISION, a division of the maturing germ-cells in which the
+dual or somatic (diploid) number of chromosomes is reduced to the single
+(haploid) number.
+
+REFLEX ACTION (L. _re_, back; _flectere_, bend), an automatic response of
+the nervous and motor mechanism of the body.
+
+RESTRICTIVE (or negative) EUGENICS, a system of improving the human race
+by preventing reproduction of the unfit.
+
+REVERSION (L. _re_, back; _verto_, turn), the reappearance of ancestral
+traits which have for some generations been in abeyance.
+
+RHEOTROPISM (Gr. _rheo_, to flow; _trope_, turning), defined, p. 198.
+
+SALPINGECTOMY (Gr. _salpinx_, trumpet; _ectome_, cutting out), removal of
+part or all of a Fallopian tube (oviduct).
+
+SEGREGATION (L. _se_, aside; _grex_, flock), separation.
+
+SEX CHROMOSOME, a special chromosome which is supposed to be concerned in
+the determination of sex.
+
+SEX-LINKED CHARACTERS, defined, p. 60.
+
+SIMIAN (L. _simia_, ape), ape-like.
+
+SIMPLEX (L. _sim_, same; _plico_, fold), the condition in which a
+character is represented by a determiner from only one of the two parents.
+
+SOMA (Gr. _soma_, body), the body considered apart from the germ-cells.
+
+SPERMATID (Gr. _sperma_, seed), a cell resulting from the last division of
+the germ-cell in spermatogenesis. It transforms into the spermatozoon.
+
+SPERMATOCYTES (Gr. _sperma_, seed; _kytos_, cell), cells concerned in the
+maturation divisions of the male germ-cells.
+
+SPERMATOGENESIS (Gr. _sperma_, seed; _genesis_, origin), the development
+of spermatozoa from primitive sex-cells.
+
+SPERMATOGONIUM (Gr. _sperma_, seed; _gonos_, generation), a primordial
+sperm-cell.
+
+SPERMATOZOON (Gr. _sperma_, seed; _zoon_, animal), the functional male
+sex-cell.
+
+SPINDLE, a fibrous organ formed in indirect cell-division.
+
+SPIREME (L. _spira_, coil), a characteristic stage preliminary to indirect
+cell-division in which the chromatin material of the nucleus appears in
+the form of a skein of filaments.
+
+STEREOTROPISM (Gr. _stereos_, solid; _trope_, turning), defined, p. 198.
+
+STERILIZATION (L. _sterilis_, barren), deprivation of reproductive power.
+For methods, see p. 322.
+
+SYNAPSE (Gr. _syn_, together; _hapto_, unite), the coming in contact of
+the processes of one nerve cell with the processes or body of another.
+
+SYNAPSIS (Gr. _syn_, together; _hapto_, unite), union of the chromosomes
+in pairs preliminary to the reduction division.
+
+TELEGONY (Gr. _telegonos_, born far away), the supposed influence of an
+earlier sire on offspring born later of the same mother to a different
+sire.
+
+THERMOTROPISM (Gr. _thero_, heat; _trope_, turning), defined, p. 198.
+
+THIGMOTROPISM (Gr. _thigmo_, touch; _trope_, turning), defined, p. 198.
+
+TOXIN (Gr. _toxicon_, poison), poisonous compounds of animal, vegetable,
+or bacterial origin.
+
+TROPISM (Gr. _trope_, turning), the automatic directing of an organism
+toward or away from a source of stimulus.
+
+UNIT-CHARACTER, a character which behaves as an indivisible unit in
+heredity.
+
+VASECTOMY (L. _vas_, vessel; _ektome_, cutting out), removal of a portion
+of the vas deferens (duct for conveying spermatozoa).
+
+VESTIGEAL (L. _vestigium_, footstep), representing organs which existed
+once in a more developed condition.
+
+VOLVOX (L. _volvo_, roll), a small fresh-water organism occurring in
+spherical colonies.
+
+WASSERMAN REACTION, a test for syphilis, see p. 188.
+
+X-ELEMENT, same as sex-chromosome.
+
+ZYGOTE (Gr. _zygon_, yolk), the product of the union of two gametes.
+
+
+
+
+REFERENCES FOR FURTHER READING AND STUDY
+
+
+BATESON, W., 1909. _Mendel's Principles of Heredity._ Cambridge, The
+University Press. The best technical account of Mendelism. It contains
+also a translation of the original papers of Mendel.
+
+CASTLE, WILLIAM E., 1911. _Heredity._ New York, D. Appleton and Company.
+
+CASTLE, WILLIAM E.; COULTER, JOHN M.; DAVENPORT, CHARLES B.; EAST, EDWARD
+M.; TOWER, WILLIAM L., 1912. _Heredity and Eugenics._ Chicago, The
+University of Chicago Press.
+
+CONKLIN, EDWIN GRANT, 1915. _Heredity and Environment in the Development
+of Men._ Princeton, Princeton University Press.
+
+DAVENPORT, CHARLES B., 1911. _Heredity in Relation to Eugenics._ New York,
+Henry Holt and Company.
+
+DONCASTER, L., 1911. _Heredity in the Light of Recent Research._
+Cambridge, The University Press.
+
+DONCASTER, L., 1915. _The Determination of Sex._ Cambridge, The University
+Press.
+
+ELLIS, HAVELOCK, 1912. _The Task of Social Hygiene._ New York, Houghton
+Mifflin Company.
+
+GALTON, FRANCIS, 1869. _Hereditary Genius: an Inquiry Into Its Laws and
+Consequences._ London, Macmillan and Company.
+
+GALTON, FRANCIS, 1889. _Natural Inheritance._ New York, The Macmillan
+Company.
+
+GALTON, FRANCIS, 1895. _English Men of Science; Their Nature and Nurture._
+New York, D. Appleton and Company.
+
+GALTON, FRANCIS, and SCHUSTER, EDGAR, 1906. _Noteworthy Families_ (Modern
+Science). London, J. Murray.
+
+GODDARD, HENRY HERBERT, 1912. _The Kallikak Family; a Study in the
+Heredity of Feeble-mindedness._ New York, The Macmillan Company.
+
+GODDARD, HENRY HERBERT, 1914. _Feeble-mindedness; Its Causes and
+Consequences._ New York, The Macmillan Company.
+
+HEALY, WILLIAM, 1915. _The Individual Delinquent._ Boston, Little, Brown
+and Company.
+
+KELLICOTT, WILLIAM E., 1911. _The Social Direction of Human Evolution; an
+Outline of the Science of Eugenics._ New York, D. Appleton and Company.
+
+MORGAN, THOMAS HUNT, 1913. _Heredity and Sex._ New York, Columbia
+University Press.
+
+PUNNETT, R. C., 1911. _Mendelism._ New York, The Macmillan Company. The
+best popular account of Mendelism.
+
+SALEEBY, CALEB WILLIAM, 1909. _Parenthood and Race Culture; an Outline of
+Eugenics._ London, Cassell and Company.
+
+SCHUSTER, EDGAR, 1912. _Eugenics._ London, Collins Clear-Type Press.
+
+THOMSON, J. ARTHUR, 1908. _Heredity._ London, John Murray.
+
+WALTER, HERBERT EUGENE, 1913. _Genetics._ New York, The Macmillan Company.
+
+WHETHAM, W. C. D. and C. D., 1909. _The Family and the Nation._ London,
+Longmans, Green and Company.
+
+WOODS, FREDERICK ADAMS, 1906. _Mental and Moral Heredity in Royalty._ New
+York, Henry Holt and Company.
+
+VARIOUS AUTHORS, 1914. _Eugenics; Twelve University Lectures._ New York,
+Dodd, Mead and Company.
+
+JOURNALS:
+
+    _The Journal of Heredity._ The organ of the American Genetic
+    Association, Washington, D. C.
+
+    _The Eugenics Review._ Issued at the University of London.
+
+    _Memoirs and Bulletins_ published by the Eugenics Record Office, Cold
+    Spring Harbor, Long Island, N. Y.
+
+Every one interested in eugenics should be acquainted with the work of
+this office. In its own words its functions are:
+
+    1. To serve eugenical interests in the capacity of repository and
+    clearing house.
+
+    2. To build up an analytical index of the traits of American families.
+
+    3. To train field workers to gather data of eugenical import.
+
+    4. To maintain a field force actually engaged in gathering such data.
+
+    5. To cooperate with other institutions and with persons concerned
+    with eugenical study.
+
+    6. To investigate the manner of inheritance of specific human traits.
+
+    7. To advise concerning the eugenical fitness of proposed marriages.
+
+    8. To publish results of researches.
+
+    To such persons as will undertake to fill them out it furnishes free
+    in duplicate (one copy to be retained by the applicant) the following
+    blank schedules: 1. _Record of Family Traits._ 2. _Index to
+    Germ-plasm--A Parallel Family Record for Prospective Marriage Mates._
+    3. _Musical Talent._ 4. _Mathematical Talent._ 5. _Tuberculosis._ 6.
+    _Special Trait Chart._ 7. _Harelip and Cleft-palate._
+
+    _Publications of the Volta Bureau_ of Washington, D. C., an
+    institution given over entirely to data regarding deaf mutes.
+
+    _Studies in National Deterioration._ The University of London.
+
+    _Memoirs and Lectures_, from the Biometric Laboratory, University of
+    London.
+
+    _Treasury of Human Inheritance_, a series of studies being issued from
+    the Eugenics Laboratory, University College, London.
+
+
+
+
+INDEX
+
+
+  Ability: 118;
+    calculating, literary, musical, 120.
+
+  Able child likely to be neglected, 257.
+
+  Achondroplasy, 113.
+
+  Acquired characters, inheritance of, 121.
+
+  Adami, 164.
+
+  Adaptations, establishment of, 140.
+
+  Adaptive responses, 201.
+
+  Agassiz, 297.
+
+  Albinism, in man, 116.
+
+  Alcohol: and crime, 279;
+    and degeneracy, 172, 179;
+    and germinal tissue, 172;
+    a poison, 168.
+
+  Alcoholism: 101, 117, 167;
+    factors in, 180;
+    in lower animals, 173-178;
+    views regarding inheritance of, 169, 170, 172, 178, 179, 180.
+
+  Alkaptonuria, 117.
+
+  Allelomorph, 77.
+
+  Alpine plants, non-inheritance of acquired characters, 131.
+
+  Alternative action in behavior, 207.
+
+  Altruism, possible origin of, 220.
+
+  Ambystoma, 132.
+
+  Ameba, 23, 24.
+
+  Ancestors, number of, 4.
+
+  Ancestry: a network, 3;
+    dual, 6;
+    in royalty, 5;
+    pride of, as a eugenic agent, 309.
+
+
+  Backward child, 256.
+
+  Backwardness, importance of early determination, 256, 257.
+
+  Bardeen, 126.
+
+  Barker, 229.
+
+  Barr, 246, 247, 248.
+
+  Barrington, 179.
+
+  Bateson, 77, 82.
+
+  Bees, inheritance in, 136, 137.
+
+  Behavior: lower animals, 197;
+    modifiability of, 200, 204-207, 217, 219, 224, 225, 337;
+    not wholly established by heredity, 217, 227;
+    rational, 205, 206;
+    various forms of, possible, 207, 219.
+
+  Bell, 152.
+
+  Bezzola, 170.
+
+  Billings, 249.
+
+  Binet-Simon test, 255.
+
+  Biometry, 16.
+
+  Birthmarks, 159, 160.
+
+  Birth-rate: significance of, 302;
+    too low in desirable stocks, 302, 304, 305, 307.
+
+  Blastomeres, 55.
+
+  Blastophthoria, 163.
+
+  Blended inheritance, 87, 92, 93.
+
+  Blends, mistakes for, 91.
+
+  Blindness, infantile, 183.
+
+  Blistering, 113.
+
+  Body: how built up from germ, 36;
+    duality of, 50.
+
+  Brachydactylism, 107.
+
+  Brain: in higher animals, 213;
+    mechanism, maladjustments of, 230.
+
+  Branthwaite, 180, 292.
+
+  Breeding, experiments, method of, 14, 15.
+
+  Brewer, 142.
+
+  Brieux, 101.
+
+  Bronner, 266.
+
+  Brown Sequard, 132, 133.
+
+
+  Cabot, 183.
+
+  Cacogenic strains, 310.
+
+  Cajal, 209.
+
+  Cancer, 117, 154.
+
+  Capsella, 131.
+
+  Castle, 134.
+
+  Cataract, presenile, 112.
+
+  Cattle: horn characters, 79;
+    roan, 81.
+
+  Cell: a unit of structure, 20;
+    diagram of, 21;
+    structure of, 20, 30.
+
+  Cell-division: 31;
+    indirect (mitosis), 32;
+    meaning of indirect, 34.
+
+  Cell-theory, 22.
+
+  Cellular basis of heredity, 22.
+
+  Ceni, 174.
+
+  Centrosome, 31.
+
+  Cerebral cortex, not functionally homogeneous, 211.
+
+  Character: defined, 12;
+    dominant, 74;
+    recessive, 74.
+
+  Characters: contrasted, 69;
+    determiners of, 13, 14;
+    independence of, 69;
+    inheritable and non-inheritable, 121, 122;
+    more than two pairs of, 87;
+    new combinations of, 82, 83, 84;
+    separable, 69;
+    symbols for, 78;
+    two pairs of, 82.
+
+  Chauvin, 132.
+
+  Chemotropism, 198.
+
+  Childbirths, intervals between, 165.
+
+  Children of the future: ours to determine quality of, 338, 339;
+    and home, 338.
+
+  Cholera, 152.
+
+  Chorea: 117;
+    Huntington's, 113-115, 243, 325.
+
+  Chromatin, 31.
+
+  Chromosome, 32.
+
+  Chromosomes: individuality of, 39, 48;
+    determiners in, 94;
+    in germ and body cells, 40;
+    Mendelian factors and, 93;
+    number and appearance, 34, 41;
+    pairs of, 40, 93, 94;
+    significance of, in heredity, 35, 49, 50, 51, 53, 54.
+
+  Chromotropism, 198.
+
+  Church, 242.
+
+  Cleavage, 36.
+
+  Cleft-palate, 178.
+
+  Cole, 166.
+
+  College graduates and birth-rate, 304.
+
+  Coloboma, 113.
+
+  Color-blindness, 60-62.
+
+  Conceptual thought, origin of, 206.
+
+  Conduct: importance to young of practise, 221, 223;
+    hereditary predisposition and, 218, 337;
+    responsibility for, 195.
+
+  Congenital traits, 123.
+
+  Conjugation, 25.
+
+  Consciousness, 206.
+
+  Conservation: of superior strains, 157;
+    human, 299, 300.
+
+  Constructive eugenics, 309.
+
+  Corneal opacity, 113.
+
+  Correns, 68.
+
+  Cortex of brain, 195, 213.
+
+  Cost, of caring for our disordered and delinquent, 257, 300.
+
+  Cretins, effects of segregating the sexes, 321.
+
+  Crime: and delinquency, 263, 287;
+    and feeble-mindedness, 264-270;
+    bearings of immigration on, 280;
+    classifications of, 276;
+    defined, 276;
+    heredity vs. environment in, 263;
+    increase in, 272;
+    mental disorders most frequently associated with, 279;
+    no specific hereditary factor for, 275.
+
+  Criminal: the born, 277;
+    the epileptic, 277.
+
+  Criminality, 117.
+
+  Criss-cross inheritance, 61.
+
+  Criteria for judging reproductive fitness, 304, 306.
+
+  Cytoplasm: 30;
+    in heredity, 51.
+
+
+  Daltonism, 60.
+
+  Dana, 257.
+
+  Darwin, pedigree of, 316.
+
+  Davenport, 92, 116, 231, 243, 257, 271, 273, 284, 291, 304, 312.
+
+  Davis, 185.
+
+  Deaf-mutism, 152, 153.
+
+  Death, natural, 28.
+
+  Decline of nations, 290, 300.
+
+  Defective delinquent, should prevent procreation of, 335.
+
+  Defectives: increase due to breeding, 290, 291;
+    natural elimination done away with among, 292;
+    unpardonable to let multiply, 288.
+
+  Defects: breeding out, 118, 119;
+    mental and nervous, 228.
+
+  Degenerate strains: 269;
+    not a product of surroundings, 273.
+
+  Degenerates, sterilization of married, 330.
+
+  Delinquency, causes of, 267, 274.
+
+  Delinquents not all defectives, 274.
+
+  Delinquent women and girls, many mentally defective, 265, 266.
+
+  Dendrite, 208.
+
+  De Sanctis, 256.
+
+  Determiners: 13, 77;
+    different producing the same character, 88, 90;
+    segregation of, 84.
+
+  Development: in higher organisms, 28;
+    suppressed, 9.
+
+  De Vries, 68.
+
+  Diabetes, 113.
+
+  Difficulty, educational value of, 222, 223.
+
+  Digital malformations, 107.
+
+  Dihybrids, 82.
+
+  Diploid number of chromosomes, 41, 43.
+
+  Disease: defined, 146;
+    inheritance of, 98, 148;
+    predisposition to, 148;
+    reappearance of not necessarily inheritance, 146.
+
+  Dominance: 74;
+    delayed, 81;
+    incomplete, 80, 100;
+    in human genealogies, 102;
+    in man, 99, 107.
+
+  Don Carlos, number of ancestors, 5.
+
+  Drosophila, 66.
+
+  Duplex character, 80, 99.
+
+  Dwarfing, by starvation, 130.
+
+  Dwarfs, true, 117.
+
+
+  East, 91.
+
+  Education: actual practise in carrying out projects important, 221;
+    affording opportunity for development of good traits, 226;
+    effects of not inherited, 142, 155;
+    establishing pathways through the nervous system, 210;
+    importance of difficulty in, 222, 223;
+    non-transference of skill acquired in one line to other lines, 213;
+    providing proper stimuli, 226;
+    training in motive necessary, 220;
+    value of interest in, 223.
+
+  Egg, a cell, 22.
+
+  Egg-cell and sperm-cell contrasted, 29.
+
+  Elderton, 179, 296.
+
+  Electrotropism, 198.
+
+  Ellis, 265, 301.
+
+  Embryo, relation to mother, 161.
+
+  Embryogeny, 36.
+
+  Emerick, 251.
+
+  Environment: direct action on germ cells, 124, 125;
+    effects of faulty, 158;
+    in crime and delinquency, 263, 266, 273, 274.
+
+  Epidermolysis, 113.
+
+  Epilepsy: 101, 117, 242, 249, 251, 252, 253;
+    in guinea-pigs, 132;
+    relation to feeble-mindedness, 249.
+
+  Epileptic, the criminal type, 277-279.
+
+  Epileptics, number of, 230, 246, 250.
+
+  Eugenic agent, educated public sentiment, 330.
+
+  Eugenics: and education, 309;
+    and personal liberty, 332;
+    a working program of, 335;
+    constructive, based on education, 301;
+    defined, 293;
+    desirable traits, 306;
+    education of women in, 333;
+    influence of public opinion on, 331;
+    much yet to be done, 333, 334;
+    positive and negative, 301.
+
+  Ewart, 10, 165.
+
+  Exceptional child likely to be neglected, 257.
+
+  Experimental breeding, method of, 15.
+
+  External conditions, influences of, 130.
+
+  Eye-color: 9, 103;
+    inheritance of, 104.
+
+  Eye-defects, 108, 110.
+
+
+  Family pride and eugenics, 309.
+
+  Farabee, 106.
+
+  Fay, 153.
+
+  Feeble-minded: prevention of procreation in, 258, 335;
+    results of non-restraint, 246.
+
+  Feeble-mindedness: 101, 117;
+    and crime, 264-269, 279;
+    grades of, 244;
+    inheritance of, 245;
+    not insanity, 238;
+    relation of alcohol to, 169-172.
+
+  Fernald, 256, 266.
+
+  Fertilization, 26, 29, 47, 48.
+
+  Fetus: poisoning of, 162;
+    relation to mother, 161.
+
+  Fiber-tracts in man, 214.
+
+  Fitness, criteria for judging, 304, 306.
+
+  Flexner, 186.
+
+  Forel, 169, 173, 303.
+
+  Fowl, Andalusian, 69, 70, 71.
+
+  Frederick the Great, number of ancestors, 5.
+
+  Friedreich's disease, 117.
+
+  Fruit-fly, 66.
+
+
+  Galton, 293, 295.
+
+  Gamete, 28, 40.
+
+  Gametes in dihybrids, 85.
+
+  Gametic matings in man, 100.
+
+  Geddes, 55.
+
+  Genealogies, imperfect, 98.
+
+  Genotype, 86.
+
+  Geotropism, 198.
+
+  Germ and body distinct, 37, 38.
+
+  Germ: control of possibilities in, 224;
+    singleness of, 50.
+
+  German emperor, number of ancestors, 5.
+
+  Germ-cells: affected by poisons, 126;
+    changes in, 126, 127;
+    early set apart, 37;
+    question of effects of body on, 128, 135;
+    effects of external influences on, 124;
+    in Miastor, 37, 38;
+    metabolic changes in, 138;
+    origin of, 36, 37;
+    possibilities of development, 127;
+    two classes of, 71, 73.
+
+  Germinal continuity, 39.
+
+  Germinal variation and the origin of new characters: 138;
+    cases analyzed, 141;
+    sexual reproduction in relation to, 138.
+
+  Germ-plasm and bad environment, 194.
+
+  Gifted persons, 212.
+
+  Glaucoma, 113.
+
+  Goddard, 118, 171, 174, 188, 235, 238, 245, 250, 256, 257, 264, 269, 326.
+
+  Gonads, transplantation of, 134.
+
+  Gonorrhoea: seriousness of, 182;
+    prevalence, 183.
+
+  Gorst, 234.
+
+  Gout, 153, 234.
+
+  Guinea-pigs: alcoholism in, 175;
+    Mendelism in, 75.
+
+  Guyer, 59.
+
+
+  Habit, 219.
+
+  Habits, modification of in lower animals, 204.
+
+  Hair-color, 105.
+
+  Hair shape, 105.
+
+  Hamburger, 150.
+
+  Handwriting, 120.
+
+  Haploid number of chromosomes, 41, 43.
+
+  Harelip, 178.
+
+  Hart, 266, 319, 326.
+
+  Healy, 256, 274, 278.
+
+  Hearing, hardness of, 118.
+
+  Heart disease, 154.
+
+  Hegner, 27, 38.
+
+  Heliotropism, 198.
+
+  Helm, 109, 111.
+
+  Hemophilia, 64.
+
+  Hereditary character defined, 12.
+
+  Hereditary mingling, mosaic rather than blend, 13.
+
+  Hereditary transmission, laws of, 68.
+
+  Heredity: and environment, 295;
+    dual ancestry in, 6;
+    defined, 1;
+    false, 163;
+    human, uncertainty of records, 98;
+    in protozoa, 22, 23;
+    in insanity, importance of, 261;
+    in sexually reproducing forms, 7;
+    in unicellular forms, 22, 23;
+    methods of study, 14, 15;
+    new discoveries in, 67;
+    not a blend, 13;
+    race betterment through, 289.
+
+  Heritage, blood, 1.
+
+  Heron, 307.
+
+  Heterozygote: 80;
+    detection of, 80.
+
+  Hill-folk, the, 271.
+
+  Hodge, 175.
+
+  Holmes, 203.
+
+  Home, for children, 338.
+
+  Homozygote, 80.
+
+  Huntington's chorea, 113-115, 243, 325.
+
+  Huxley, 195, 205.
+
+  Hybrids: 52;
+    whites and negroes, 297, 298.
+
+  Hypotrichosis, 113.
+
+  Hysteria, 117.
+
+
+  Ichthyosis, 65.
+
+  Ideals, importance of establishing in children, 223.
+
+  Idiots, 244.
+
+  Imbeciles, 244.
+
+  Immigrants, duty of excluding undesirable, 335.
+
+  Immigration: and mental unsoundness, 281, 282;
+    bearing on crime and delinquency, 280;
+    bearing on venereal diseases, 282;
+    importance of restricting, 283, 335.
+
+  Immortality: of protozoa, 23;
+    of the race, 3.
+
+  Immunity, artificial, not inherited, 155.
+
+  Inbreeding, in defectives, 271.
+
+  Individual, and race, 3.
+
+  Inebriate women, offspring of, 168.
+
+  Inebriety, constitutional, 180.
+
+  Infant mortality, 149.
+
+  Infection, prenatal, 147.
+
+  Inheritance: and disease, 146;
+    blended, 87, 93;
+    of tendencies, 107.
+
+  Inhibitions, 216.
+
+  Inhibitors, 79.
+
+  Insane, increase in numbers of, 233, 234.
+
+  Insanity: 117;
+    certain forms recessive, 243;
+    eugenical significance of, 234, 235, 240;
+    importance of early diagnosis, 259;
+    some forms not hereditary, 260;
+    types of, 239;
+    prevalence in the United States, 228, 229.
+
+  Insect colors, effect of temperature, 129.
+
+  Instincts: 203;
+    adjustable, 203;
+    not inherited acquirements, 144;
+    origin of intelligent behavior from, 203, 204.
+
+  Institutional figures misleading, 266.
+
+  Intelligence, 205, 206.
+
+  Intelligent behavior, opening up possibilities of, 204.
+
+  Ireland, 171.
+
+  Irritability, characteristics of living protoplasm, 197.
+
+
+  Jennings, 203, 204.
+
+  Johnson, 305.
+
+  Johnstone, 245, 319, 320, 321.
+
+  Jolly, 243.
+
+  Jordan, 4, 299.
+
+  Jukes, 270.
+
+
+  Kallikak family, 269, 270.
+
+  Kellicott, 314, 316.
+
+  Kellogg, 299.
+
+  Keratosis, 113.
+
+  Kidney diseases, 154.
+
+  Kirby, 187, 324.
+
+  Knox, 256.
+
+  Kraeplin, 242.
+
+
+  Laitinen, 174.
+
+  Language, as mental aid, 206, 207.
+
+  Lapsed intelligence, theory of, 145.
+
+  Larval stages, susceptibility of, 128.
+
+  Laws, sterilization, 323, 327, 329.
+
+  Lead-poisoning: 163;
+    experiments on rabbits, 163.
+
+  Lederbaur, 131.
+
+  Legal restraint of defectives limited, 331.
+
+  Lens: displaced, 113;
+    cataract, 112.
+
+  Leprosy, 152.
+
+  Leptinotarsa, production of variations in, 125.
+
+  Linden, Countess von, 129.
+
+  Linin, 31.
+
+  Little's disease, 215.
+
+  Locomotor ataxia, 187.
+
+  Loeb, 62, 203.
+
+  Longevity, 120.
+
+  Lord Morton's mare, 10.
+
+  Lorenz, 113, 114, 115.
+
+  Low birth-rate, 308.
+
+  Lowell, Judge John, 312.
+
+  Luetin test, 188.
+
+  Lunborg, 243.
+
+
+  MacDougal, 125.
+
+  Margaret, Mother of Criminals, 270.
+
+  Marriage: barriers to, 331;
+    inter-racial, 296;
+    medical inspection before, 191.
+
+  Mast, 203.
+
+  Maternal impressions, 159-160.
+
+  Maturation: 39, 41, 43, 44;
+    parallel between egg and sperm-cell, 44, 46.
+
+  Mechanical skill, 120.
+
+  Mechanism of heredity, 22, 25, 26, 28, 29, 30, 35, 37, 40-54, 94, 95.
+
+  Melancholia and crime, 279.
+
+  Memory: 120, 204;
+    not a complete test of normality, 268, 269.
+
+  Mendel: 68;
+    work on peas, 82.
+
+  Mendelian factors and chromosomes: 93;
+    inheritance and man, 97;
+    principles, rediscovery of, 68;
+    ratio, cause of, 71.
+
+  Mendelism, 67, 69.
+
+  Mental and nervous defects, 228.
+
+  Mental defective: defined, 255;
+    disproportionate increase in, 232;
+    numbers married, 231, 232;
+    inefficiency of marriage laws concerning, 315.
+
+  Mental deficiency: not always inherited, 248;
+    tests for, 254, 255.
+
+  Mental organization of lower vertebrates, 205.
+
+  Mental process as neural process, 195.
+
+  Mental unsoundness, 196.
+
+  Mentality, inheritance of, 19.
+
+  Mentally disordered, cost of caring for, 257, 258.
+
+  Mercier, 279.
+
+  Merriere's disease, 117.
+
+  Metazoa, 28.
+
+  Metz, 41.
+
+  Mice, 78.
+
+  Michigan, state report on mentally defective, 234.
+
+  Migraine, 101.
+
+  Mind, relation to brain, 195.
+
+  Mitosis: 32, 33;
+    meaning of, 34, 37.
+
+  Mjöen, 171.
+
+  Modifiability of behavior, 200, 204, 205, 207, 217, 219, 224, 225, 337.
+
+  Mongolians, 248.
+
+  Moral responsibility, 227.
+
+  Morgan, C. Lloyd, 146, 211.
+
+  Morgan, T. H., 59, 66.
+
+  Moron, 244, 268.
+
+  Morons and crime, 268.
+
+  Mosaic, heredity a, 13.
+
+  Motherhood, safeguarding, 165.
+
+  Motive, training in, 220.
+
+  Mott, 150.
+
+  Mulattoes, 92.
+
+  Multiple sclerosis, 64, 117.
+
+  Muscular atrophy: 113;
+    Gower's, 65.
+
+  Musical ability, 120.
+
+  Mutations: artificial production of, 125;
+    germinal, 125.
+
+  Mutilations, non-inheritance of, 134.
+
+  Myopia, 64.
+
+
+  Naegeli, 131.
+
+  Nam family, 271.
+
+  Natural selection partly done away with in human society, 292.
+
+  Near-sightedness, 64.
+
+  Nervous and mental diseases, 153.
+
+  Nervous organization, inheritable, 242.
+
+  Nervous response, in lower organisms, 196.
+
+  Nervous system: mainly inherited, 210, 216;
+    establishment of pathways in, 210;
+    maladjustments of, 231;
+    special developments in man, 213, 214, 215;
+    units of, 208.
+
+  Nervous systems of anthropoids, 214.
+
+  Neural pathways, not all established at birth, 217.
+
+  Neuritis optica, 65.
+
+  Neurons, 208.
+
+  Neuron theory, 208.
+
+  Neuropathic constitution, expression of, 241.
+
+  Neuropathic defects, carriers of, 253.
+
+  Neuter insects, heredity in, 136, 137.
+
+  New characters, origin of, 138.
+
+  Newman, 56.
+
+  Nicloux, 172.
+
+  Night-blindness, 65.
+
+  Nilsson-Ehle, 88, 89.
+
+  Noguchi, 186.
+
+  Nucleolus, 31.
+
+  Nucleus, structure of, 31.
+
+  Nulliplex character, 80, 100.
+
+
+  Obesity, 120, 154.
+
+  Offspring: from one parent only, 5;
+    different from either parent, 12.
+
+  Oöcyte, primary, secondary, 44.
+
+  Oögenesis, 44.
+
+  Oögonia, 44.
+
+  Optic nerve, atrophy of, 64.
+
+  Organs, formation of, 36.
+
+  Origin of sex cells, 12, 36.
+
+  Ovaries, transplantation of, 134.
+
+  Ovum, 26, 40.
+
+
+  Paralysis, general, 186.
+
+  Paranoia, 279.
+
+  Parent-body and germ distinct, 12.
+
+  Parenthood, cultivation of wholesome sentiment toward, 336.
+
+  Paresis: 186;
+    and crime, 279.
+
+  Parthenogenesis, 6.
+
+  Patterson, 56.
+
+  Paul, 163.
+
+  Pearson, 150, 151, 179, 296, 307.
+
+  Peas, 68, 82.
+
+  Performance tests, 256.
+
+  Peron, 133.
+
+  Personality determined by heredity, 2, 195.
+
+  Peterson, 242.
+
+  Phenotype, 86.
+
+  Phillips, 134, 135.
+
+  Phototropism, 198.
+
+  Pinard, 165.
+
+  Pineys, the, 271.
+
+  Plato, 290.
+
+  Poellman, 271.
+
+  Polar bodies, 44, 45.
+
+  Polydactyly, 108.
+
+  Potato-beetle, production of variations in, 125.
+
+  Potts, 292.
+
+  Predisposition to disease, 148.
+
+  Pregnancy, neglect of mothers during, 165.
+
+  Prenatal care: 336;
+    infection, 147;
+    influence, 11, 159, 162.
+
+  Prenuptial medical inspection desirable, 336.
+
+  Presence and absence theory: 78;
+    formulæ for man, 99.
+
+  Primrose, experiments on, 125.
+
+  Principles, Mendelian, 68.
+
+  Prisoners, many mentally subnormal, 266.
+
+  Pronucleus, 47.
+
+  Protective coloration, not of somatic origin, 135, 136.
+
+  Protoplasm, germinal, 39.
+
+  Psychical development, 196, 203, 205, 206, 213, 215.
+
+  Pyramidal tracts, 214.
+
+
+  Quagga hybrid, 10.
+
+
+  Race amalgamation: 297, 298;
+    deterioration, in a selected population, 303.
+
+  Racial degeneracy, not curable by improved environment alone, 294.
+
+  Ratio: the 1:2:1, 73;
+    the 3:1, 77;
+    the 9:3:3:1, 85;
+    the 27:9:9:9:3:3:3:1, 87;
+    the 15:1, 88;
+    the 63:1, 90.
+
+  Rational behavior, 205, 206.
+
+  Reason, 206.
+
+  Recessiveness: 74;
+    in man, 115.
+
+  Records of family traits desirable, 337.
+
+  Reduction division, 41, 42.
+
+  Reflexes, 203.
+
+  Regression, law of, 17.
+
+  Renault, 172.
+
+  Rentoul, 232.
+
+  Reproduction: asexual, 6, 26;
+    sexual, 26;
+    sexual and variation, 139.
+
+  Reproductive cells, 27, 28, 29.
+
+  Responsibility for conduct, 195.
+
+  Rest, importance of, in pregnancy, 165.
+
+  Reversion: 7, 8;
+    and atavism, 8;
+    in guinea-chicken hybrids, 8.
+
+  Rheotropism, 198.
+
+  Rheumatism, 154.
+
+  Ritter, 143.
+
+  Rogers, 246, 272.
+
+  Romanes, 133.
+
+  Rosanoff, 243.
+
+  Rossolimo, 256.
+
+  Rudin, 243.
+
+
+  Salpingectomy, 322.
+
+  Sanford, 205.
+
+  St. Vitus' dance, 117.
+
+  Schulze, 24.
+
+  Schuster, 296.
+
+  Sclerosis, multiple, 64, 117.
+
+  Segregation: in dihybrids, 84;
+    Mendelian, 69, 70, 75;
+    of defectives, 318.
+
+  Seguin, 256.
+
+  Self-control, importance of, 221, 267, 268, 284, 286, 287.
+
+  Sex: and chromosomes, 59;
+    and heredity, 53;
+    cells of Volvox, 25;
+    chromosome, 57, 58;
+    determination, 55;
+    differentiation and X-element, 60;
+    evolution of, 25-30;
+    hygiene, question of school instruction in, 285;
+    in certain insects, 56;
+    linked characters, 60, 65;
+    not a necessary factor in heredity, 6;
+    problem, knowledge alone not sufficient, 286.
+
+  Sexual vice, 284.
+
+  Sharp, 322.
+
+  Simplex character, 80, 99.
+
+  Skill, non-transference in brain, 212, 213.
+
+  Skin, color of, 92.
+
+  Smallpox, 152.
+
+  Social maladies, prevention of, 293.
+
+  Softening of the brain, 186.
+
+  Soma, 28.
+
+  Spermatid, 43.
+
+  Spermatocyte, primary, secondary, 43.
+
+  Spermatogenesis, 42.
+
+  Spermatogonium, 43.
+
+  Spermatazoon: 26, 40;
+    a cell, 22;
+    formation of, 43;
+    structure of, 43.
+
+  Spindle, in cell-division, 32.
+
+  Spottedness of hair-coat, 113.
+
+  Sprague, 281, 305.
+
+  Starfish, training a, 204.
+
+  Statistical methods, 15.
+
+  Statistics, trustworthy needed, 334.
+
+  Stature, inheritance of, 17.
+
+  Stereotropism, 198.
+
+  Sterility, 182.
+
+  Sterilization: 322;
+    in epilepsy, 326;
+    laws, 323;
+    laws, on trial, 329;
+    laws, states having, 327.
+
+  Stevens, 41.
+
+  Stockard, 174-178.
+
+  Strength, muscular, 120.
+
+  Stripes, reversionary, 8.
+
+  Stutzman, 305.
+
+  Sullivan, 168.
+
+  Superior strains, conservation of, 157.
+
+  Synapse, 210.
+
+  Synapsis, 41, 42.
+
+  Syndactyly, 65, 108, 111.
+
+  Syphilis: 184-190;
+    and prostitutes, 185;
+    cerebro-spinal form, 189-190;
+    prenuptial inspection for, 190-192;
+    prevalence, 186;
+    stages of, 185;
+    tests for, 188.
+
+  Syphilitics: children of, 187, 188;
+    married, 190.
+
+
+  Tabes dorsalis, 186.
+
+  Taints, 101.
+
+  Talent, inheritance of, 212.
+
+  Taylor, 297.
+
+  Telegony, alleged cases of, 10.
+
+  Temperament, inheritance of, 19.
+
+  Thermotropism, 198.
+
+  Thigmotropism, 198.
+
+  Third generation, segregation in, 69.
+
+  Thomsen's disease, 118.
+
+  Thomson, 55.
+
+  Thorndike, 296.
+
+  Tower, 125.
+
+  Training of children: and heredity, 218;
+    faults in, 221, 222.
+
+  Transmission, not necessarily inheritance, 163.
+
+  Tredgold, 170.
+
+  Treponema pallidum, 185.
+
+  Tribe of Ishmael, 271.
+
+  Tropic responses: often purposeful, 201;
+    uncertainties in, 202.
+
+  Tropisms: 197;
+    complications in, 200;
+    in plants and animals, 198;
+    relations to reflex actions and instincts, 203.
+
+  Tschermak, 68.
+
+  Tuberculosis, 118, 148-160, 162.
+
+  Twins: identical, 55;
+    sex of, 55.
+
+  Typhoid, 152.
+
+
+  Unemployed, frequently morons, 280.
+
+  Unfit, elimination of, urgent, 313.
+
+  Unit-character: 12;
+    inheritance of, 13.
+
+  Unicellular organisms: 21;
+    inheritance in, 22, 23.
+
+  Use and disuse, 122.
+
+
+  Van Ingen, 167.
+
+  Vasectomy, 322.
+
+  Venereal disease, 182.
+
+  Virchow, 147.
+
+  Voison, 133.
+
+  Volitions as tropisms, 199.
+
+  Volvox, 25, 26, 27.
+
+
+  War, eugenical effects of, 299.
+
+  Wasserman, provocative, 189.
+
+  Wasserman test, 188, 189.
+
+  Webbed digits, 65.
+
+  Weeks, 251, 252, 253, 291.
+
+  West, 167.
+
+  Wheat, 75, 81, 88.
+
+  Whetham, 314, 316.
+
+  Whitman, 145.
+
+  Wilmarth, 243, 245, 274, 291.
+
+  Wilson, 59, 62, 94, 95.
+
+  Woods, 296.
+
+
+  X-element, 57, 58.
+
+
+  Zebra hybrids, 10.
+
+  Zeros, the, 271.
+
+  Zygote: 26, 27;
+    chromosomes of, 40.
+
+
+
+
+FOOTNOTES:
+
+[1] The reader desiring more detailed information will find fuller
+discussions in the following:
+
+Wilson, E. B.: _Recent Researches on the Determination and Heredity of
+Sex_. Science, January 8, 1909.
+
+Wilson, E. B.: _The Chromosomes in Relation to the Determination of Sex_.
+Science Progress, April, 1910.
+
+Guyer, M. F.: _Recent Progress in Some Lines of Cytology_. Transactions of
+the American Microscopical Society, April, 1911.
+
+Morgan, T. H.: _Heredity and Sex_. Columbia University Press, 1913.
+
+[2] A translation of Mendel's original papers will be found in _Mendel's
+Principles of Heredity_, by W. Bateson.
+
+[3] _Heredity of Skin Color in Negro and White Crosses_: Publication No.
+188, of the _Carnegie Institution of Washington_.
+
+[4] Whitman, C. O.: _Animal Behavior, Biological Lectures_, Marine
+Biological Laboratory, 1898.
+
+[5] _The Fight Against Tuberculosis and the Death Rate from Phthisis_,
+London, Dulau & Co., 1911.
+
+[6] Forel, August: _The Sexual Question_, p. 268.
+
+[7] Loc. cit. p. 251.
+
+[8] In this connection it is instructive to note from a Michigan state
+report, just off the press, that, among 4,917 insane individuals
+concerning whom satisfactory information was obtained, 65.4 per cent. "had
+among their ancestors or family such hereditary influences as insanity,
+apoplexy or paralysis, psychopathic abnormalities or alcoholism." See
+_Report of the Commission to Investigate the Extent of Feeble-mindedness,
+Epilepsy, Insanity and Other Conditions of Mental Defectiveness in
+Michigan_. Wynkoop Hollenbeck Crawford Co., State Printers, Lansing,
+Michigan, 1915.
+
+[9] _Feeble-mindedness; Its Causes and Consequences_, by Henry H. Goddard,
+The Macmillan Company, 1914.
+
+[10] _The Binet-Simon Measuring Scale for Intelligence_, by Henry H.
+Goddard, 1911. The Training School, Vineland, N. J. Price 15 cents.
+
+[11] "Tests for Mental Defects," by Howard A. Knox, _Journal of Heredity_,
+March, 1914. See also Knox: _Journal of the American Medical Association_,
+1914.
+
+[12] _The Individual Delinquent_, by William Healy, M. D. Little, Brown &
+Co., Boston.
+
+[13] _The Individual Delinquent_, by William Healy, M. D. Little, Brown &
+Co., Boston.
+
+[14] The Psycopathic Laboratory in connection with the Juvenile Court of
+Chicago.
+
+[15] See "The Foreign Born in the United States." _The National Geographic
+Magazine_, September, 1914.
+
+[16] See First Report of the Committee of the Eugenic Section of the
+American Breeders' Association, "On Immigration", _American Breeders'
+Magazine_, Vol. III, No. 4, 1912. Also Second Report of same, _The Journal
+of Heredity_, July, 1914.
+
+[17] "The Negro and His Health Problems," _Medical Record_, September 12,
+1912.
+
+[18] See D. S. Jordan, _The Human Harvest_, or V. L. Kellogg, _Eugenics
+and Militarism_.
+
+[19] For arguments indicating the superior eugenical fitness of college
+graduates see "Wellesley's Birth-Rate," by Roswell H. Johnson and Bertha
+Stutzman, _The Journal of Heredity_, June, 1915. See also, "Education and
+Race Suicide," by Robert J. Sprague, _ibid._, April, 1915.
+
+[20] Since the present manuscript went to press an excellent government
+report (_Insane and Feeble-Minded in Institutions in 1910_, Department of
+Commerce, Bureau of the Census, 1914, Washington, D. C.) has appeared. In
+it one finds the estimate that not over one-tenth of our feeble-minded are
+being cared for in special institutions.
+
+[21] For summaries of existing sterilization laws and statements of the
+issues involved see (1) _The Legal, Legislative, and Administrative
+Aspects of Sterilisation_, Bulletin 10B, February 3, 1914, Eugenics Record
+Office, Cold Spring Harbor, N. Y.; (2) _Sterilisation of Criminals_,
+Report of Committee H of the American Institute of Criminal Law and
+Criminology, Bulletin No. XV, September, 1914.
+
+
+
+
+Transcriber's Notes:
+
+Passages in italics are indicated by _italics_.
+
+Passages in bold are indicated by =bold=.
+
+Superscripted characters are indicated by ^{superscript}.
+
+Subscripted characters are indicated by _{subscript}.
+
+The original text contains a few letters with diacritical marks that are
+not represented in this text version.
+
+The original text contains male and female symbols. These are represented
+as [male] and [female].
+
+
+
+
+
+
+End of the Project Gutenberg EBook of Being Well-Born, by Michael F. Guyer
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+      Being Well-Born, by Michael F. Guyer&mdash;A Project Gutenberg eBook
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+The Project Gutenberg EBook of Being Well-Born, by Michael F. Guyer
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+This eBook is for the use of anyone anywhere at no cost and with
+almost no restrictions whatsoever.  You may copy it, give it away or
+re-use it under the terms of the Project Gutenberg License included
+with this eBook or online at www.gutenberg.org
+
+
+Title: Being Well-Born
+       An Introduction to Eugenics
+
+Author: Michael F. Guyer
+
+Editor: M. V. O'Shea
+
+Release Date: May 21, 2012 [EBook #39751]
+
+Language: English
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+*** START OF THIS PROJECT GUTENBERG EBOOK BEING WELL-BORN ***
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+
+
+
+<div class="figcenter"><img src="images/cover.jpg" alt="" /></div>
+<p>&nbsp;</p><p>&nbsp;</p>
+
+<h1><small>BEING WELL-BORN</small></h1>
+
+
+<p>&nbsp;</p><p>&nbsp;</p>
+<p class="center"><span class="giant">BEING WELL-BORN</span></p>
+<p class="center">AN INTRODUCTION TO EUGENICS</p>
+<p>&nbsp;</p>
+<p class="center"><i>By</i><br />
+<span class="large">MICHAEL F. GUYER, <span class="smcap">Ph. D.</span></span><br />
+Professor of Zoology, The University of Wisconsin</p>
+<p>&nbsp;</p>
+<p class="center">Childhood and Youth Series<br />
+<i>Edited by</i> M. V. O&#8217;SHEA<br />
+Professor of Education, The University of Wisconsin</p>
+<p>&nbsp;</p>
+<p class="center">INDIANAPOLIS<br />
+THE BOBBS-MERRILL COMPANY<br />
+PUBLISHERS</p>
+
+
+
+<p>&nbsp;</p><p>&nbsp;</p>
+<p class="center"><span class="smcap">Copyright 1916<br />
+The Bobbs-Merrill Company</span></p>
+
+<p class="center">PRESS OF<br />
+BRAUNWORTH &amp; CO.<br />
+BOOKBINDERS AND PRINTERS<br />
+BROOKLYN, N. Y.</p>
+
+
+<p>&nbsp;</p><p>&nbsp;</p>
+<p class="center">TO MY WIFE<br />
+HELEN M. GUYER</p>
+
+
+<p>&nbsp;</p><p>&nbsp;</p>
+<hr style="width: 50%;" />
+<h2>EDITOR&#8217;S INTRODUCTION</h2>
+
+
+<p>The writer recalls that when he was a young boy, he heard the grown-up
+people in the community earnestly and incessantly debating the question:
+Does heredity play a greater part in shaping one&#8217;s mind and body than does
+his environment? From that day to this he has listened to men and women in
+every walk of life discussing the relation of heredity to environment in
+determining human traits. Teachers and parents are constantly asking: &#8220;Are
+such and such characteristics in my children due to their inheritance or
+to the way they have been trained?&#8221; Students of juvenile delinquency and
+of mental defect and deficiency are searching everywhere for light on this
+matter. It is not to be wondered at that practically all people are
+peculiarly interested in this problem, since it concerns intimately one&#8217;s
+personal traits, and it constantly confronts any one who is responsible
+for the care and culture of the young.</p>
+
+<p>It is suggestive to note how people differ in their views regarding the
+extent to which a child&#8217;s physical and mental qualities and capacities are
+fixed definitely by his inheritance. The writer has often heard students
+in university classes discuss the subject; and their handling of the
+problem has shown how superficially and even superstitiously most persons
+regard the mechanism and functions of heredity. It is significant also to
+observe what extreme views many people hold regarding the possibility of
+affecting a child&#8217;s traits and abilities by subjecting him to specific
+influences during his prenatal life. In any group of one hundred persons
+chosen at random, probably seventy-five will believe in specific prenatal
+influence. Many of them will believe in birthmarks due to peculiar
+experiences of the mother. A popular book recently published asserts among
+other things that if a mother will look upon beautiful pictures and listen
+to good music during the prenatal period of her child, the latter will
+possess esthetic traits and interests in high degree. On the other hand,
+people generally do not seem to think that degenerate parents beget only
+degenerate children. Alcoholics, feeble-minded persons and the like are
+permitted to bring children into the world.</p>
+
+<p>Very few people have any precise knowledge of the mechanism of heredity.
+The whole thing is inscrutable to them, and is shrouded in mystery.
+Superstition flourishes among even intelligent persons in respect to
+heredity, and errors due to education, and tragedies resulting from
+vicious social organization are all alike ascribed to its uncontrollable
+forces. Most people are none the wiser because they do not know to what
+extent the physical and mental defects and deviations of individuals are
+due to inheritance or to the malign influences of the individual&#8217;s
+environment and training.</p>
+
+<p>Professor Guyer, who has studied the whole problem in a thoroughgoing,
+scientific way, has prepared this book with a view to illuminating some of
+the mysteries that surround the subject of heredity, and to dispelling
+the illusions that persist regarding it. He shows the method which nature
+follows in the development of the individual. He presents the laws which
+have become established respecting the extent to which and the manner in
+which immediate and remote ancestors contribute to the child&#8217;s physical
+and mental organism. He answers many questions which those who are engaged
+in social work or in education in the home or the school are asking
+to-day. He discusses subjects upon which every serious-minded person
+wishes to be informed. He has thus made a book which is both of
+theoretical and of practical interest.</p>
+
+<p>He has written in a style which should make his book attractive to the
+parent and the teacher as well as to the student of the complicated
+mechanism of inheritance. Only a few special terms are used, and these
+should not give any reader trouble, because the treatment throughout is so
+concrete that the meaning of the terms will be easily grasped. Further,
+the book is illustrated, with many attractive and instructive
+illustrations which will show at a glance the working of the principles of
+inheritance which are developed in the text.</p>
+
+<p>This book may be heartily commended to all who are interested in questions
+of human nature, education and social reform. It should enable the parent,
+the teacher and the legislator to understand more clearly than most of
+them now do in how far children&#8217;s traits and possibilities are or can be
+fixed by inheritance as contrasted with environmental conditions and
+nurture in home, school, church and institutional life.</p>
+
+<p><span style="margin-left: 2em;"><span class="smcap">M. V. O&#8217;Shea.</span></span></p>
+
+<p>Madison, Wisconsin.</p>
+
+
+
+<p>&nbsp;</p><p>&nbsp;</p>
+<hr style="width: 50%;" />
+<h2>PREFACE</h2>
+
+
+<p>One of the most significant processes at work in society to-day is the
+awakening of the civilized world to the rights of the child; and it is
+coming to be realized that its right of rights is that of being well-born.
+Any series of publications, therefore, dealing primarily with the problems
+of child nature may very fittingly be initiated by a discussion of the
+factor of well-nigh supreme importance in determining this nature,
+heredity.</p>
+
+<p>No principles have more direct bearing on the welfare of man than those of
+heredity, and yet on scarcely any subject does as wide-spread ignorance
+prevail. This is due in part to the complexity of the subject, but more to
+the fact that in the past no clear-cut methods of attacking the manifold
+problems involved had been devised. Happily this difficulty has at least
+in part been overcome.</p>
+
+<p>It is no exaggeration to say that during the last fifteen years we have
+made more progress in measuring the extent of inheritance and in
+determining its elemental factors than in all previous time. Instead of
+dealing wholly now with vague general impressions and speculations,
+certain definite principles of genetic transmission have been disclosed.
+And since it is becoming more and more apparent that these hold for man as
+well as for plants and animals in general, we can no longer ignore the
+social responsibilities which the new facts thrust upon us.</p>
+
+<p>Since what a child becomes is determined so largely by its inborn
+capacities it is of the greatest importance that teachers and parents
+realize something of the nature of such aptitudes before they begin to
+awaken them. For education consists in large measure in applying the
+stimuli necessary to set going these potentialities and of affording
+opportunity for their expression. Of the good propensities, some will
+require merely the start, others will need to be fostered and coaxed into
+permanence through the stereotyping effects of proper habits; of the
+dangerous or bad, some must be kept dormant by preventing improper
+stimulation, others repressed by the cultivation of inhibitive tendencies,
+and yet others smothered or excluded by filling their place with desirable
+traits before they themselves come into expression.</p>
+
+<p>We must see clearly, furthermore, that even the best of pedagogy and
+parental training has obvious limits. Once grasp the truth that a child&#8217;s
+fate in life is frequently decided long before birth, and that no amount
+of food or hospital service or culture or tears will ever wholly make good
+the deficiencies of bad &#8220;blood,&#8221; or in the language of the biologist, a
+faulty germ-plasm, and the conviction must surely be borne home to the
+intelligent members of society that one thing of superlative importance in
+life is the making of a wise choice of a marriage mate on the one hand,
+and the prevention of parenthood to the obviously unfit on the other.</p>
+
+<p>In the present volume it is intended to examine into the natural
+endowment of the child. And since full comprehension of it requires some
+understanding of the nature of the physical mechanism by which hereditary
+traits are handed on from generation to generation, a small amount of
+space is given to this phase. Then, that the reader may appreciate to
+their fullest extent the facts gathered concerning man, a review of the
+more significant principles of genetics as revealed through experiments in
+breeding plants and animals has been undertaken. The main applications of
+these principles to man is pointed out in a general discussion of human
+heredity. Finally, inasmuch as all available data indicate that the fate
+of our very civilization hangs on the issue, the work concludes with an
+account of the new science of eugenics which is striving for the
+betterment of the race by determining and promulgating the laws of human
+inheritance so that mankind may intelligently go about conserving good and
+repressing bad human stocks.</p>
+
+<p>In order to eliminate as many errors as possible and to avoid oversights I
+have submitted various chapters to certain of my colleagues and friends
+who are authorities in the special field treated therein. While these
+gentlemen are in no way responsible for the material of any chapter they
+have added greatly to the value of the whole by their suggestions and
+comments. Thus I am indebted to Professor Leon J. Cole for reading the
+entire manuscript; to Professors A. S. Pearse and F. C. Sharp for reading
+Chapter VII; to Professor C. R. Bardeen for reading special parts; to
+Doctor J. S. Evans for reading Chapter VI and part of V; to Doctor W. F.
+Lorenz, of the Mendota Hospital, for reading Chapter VIII; to Judge E. Ray
+Stevens for reading Chapter IX, and to Helen M. Guyer for several readings
+of the entire manuscript.</p>
+
+<p>Grateful acknowledgment is made to all of these readers, to various
+publishers and periodicals for the use of certain of the illustrations, to
+the authors of the numerous books and papers from which much of the
+material in such a work as this must necessarily be selected, and to my
+artist, Miss H. J. Wakeman, for her painstaking endeavors to make her work
+conform to my ideas of what each diagram should show.</p>
+
+<p><span style="margin-left: 2em;">M. F. G.</span></p>
+
+
+
+<p>&nbsp;</p><p>&nbsp;</p>
+<hr style="width: 50%;" />
+<p class="title">CONTENTS</p>
+
+<table border="0" cellpadding="0" cellspacing="5" summary="table">
+<tr><td><small>CHAPTER</small></td>
+    <td>&nbsp;</td>
+    <td align="right"><small>PAGE</small></td></tr>
+<tr><td align="right"><a href="#CHAPTER_I">I</a></td>
+    <td align="center"><span class="smcap">Heredity</span></td>
+    <td align="right"><a href="#Page_1">1</a></td></tr>
+<tr><td>&nbsp;</td><td class="summary">Blood heritage&mdash;Kind determined by origin&mdash;Ancestry a network&mdash;Ancestry in royalty&mdash;Offspring
+derived from one parent only&mdash;Dual ancestry an aid in studying heredity&mdash;Reversion&mdash;Telegony&mdash;Prenatal influences apart from heredity&mdash;Parent
+body and germ not identical&mdash;A hereditary character defined&mdash;Hereditary mingling a mosaic rather than a blend&mdash;Determiners
+of characters, not characters themselves, transmitted&mdash;Our knowledge of heredity derived along three lines&mdash;The method of
+experimental breeding&mdash;The statistical method&mdash;Galton&#8217;s law of regression&mdash;Correlations between
+parents and offspring&mdash;The biometrical method, statistical, not physiological&mdash;Mental as well as physical qualities inheritable.</td></tr>
+<tr><td>&nbsp;</td></tr>
+<tr><td align="right"><a href="#CHAPTER_II">II</a></td>
+    <td align="center"><span class="smcap">The Bearers of the Heritage</span></td>
+    <td align="right"><a href="#Page_20">20</a></td></tr>
+<tr><td>&nbsp;</td><td class="summary">The cell the unit of structure&mdash;Unicellular organisms&mdash;Importance of cell-theory&mdash;Heredity
+in unicellular forms&mdash;Reproduction and heredity in colonial protozoa&mdash;Conjugation&mdash;Specialization
+of sex-cells&mdash;The fertilized ovum&mdash;Advancement seen in the Volvox colony&mdash;Natural death&mdash;Specialization in higher organisms&mdash;Sexual
+phenomena in higher forms&mdash;Cell-division&mdash;Chromosomes constant in number and appearance&mdash;Significance of the chromosomes&mdash;Cleavage
+of the egg&mdash;Chief processes operative in building the body&mdash;The origin of the new germ-cells&mdash;Significance of the early setting
+apart of the germ-cells&mdash;Individuality of chromosomes&mdash;Pairs of chromosomes&mdash;Reduction of the number of chromosomes by one-half&mdash;Maturation
+of the sperm-cell&mdash;Maturation of the egg-cell&mdash;Parallel between the two processes&mdash;Fertilization&mdash;Significance of the behavior
+of the chromosomes&mdash;A single set of chromosomes sufficient for the production of an organism&mdash;The duality of the body and the singleness
+of the germ&mdash;The cytoplasm in inheritance&mdash;Chromosomes possibly responsible for the distinctiveness of given characters&mdash;Sex
+and heredity&mdash;Many theories of sex determination&mdash;The sex-chromosome&mdash;Sex-linked characters in man&mdash;In lower forms.</td></tr>
+<tr><td>&nbsp;</td></tr>
+<tr><td align="right"><a href="#CHAPTER_III">III</a></td>
+    <td align="center"><span class="smcap">Mendelism</span></td>
+    <td align="right"><a href="#Page_67">67</a></td></tr>
+<tr><td>&nbsp;</td><td class="summary">New discoveries in the field of heredity&mdash;Mendel&mdash;Rediscovery of Mendelian principles&mdash;Independence
+of inheritable characters&mdash;Illustration in the Andalusian fowl&mdash;The cause of the ratio&mdash;Verification of the hypothesis&mdash;Dominant
+and recessive&mdash;Segregation in the next generation&mdash;Illustrated in guinea-pigs&mdash;Terminology&mdash;The theory of presence and absence&mdash;Additional
+terminology&mdash;Dominance not always complete&mdash;Modifications of dominance&mdash;Mendel&#8217;s own work&mdash;Dihybrids&mdash;Getting new combinations
+of characters&mdash;Segregations of the determiners&mdash;Four kinds of gametes in each sex&mdash;The 9:3:3:1 ratio&mdash;Phenotype and genotype&mdash;The
+question of blended inheritance&mdash;Nilsson-Ehle&#8217;s discoveries&mdash;Such cases easily mistaken for true blends&mdash;Skin-color in man&mdash;Questionable
+if real blends exist&mdash;The place of the Mendelian factors in the germ-cell&mdash;Parallel between the behavior of Mendelian
+factors and chromosomes&mdash;A single chromosome not restricted to carrying a single determiner.</td></tr>
+<tr><td>&nbsp;</td></tr>
+<tr><td align="right"><a href="#CHAPTER_IV">IV</a></td>
+    <td align="center"><span class="smcap">Mendelism in Man</span></td>
+    <td align="right"><a href="#Page_97">97</a></td></tr>
+<tr><td>&nbsp;</td><td class="summary">Probably applicable to many characters in man&mdash;Difficult to get correct data&mdash;A generalized
+presence-absence formula&mdash;Indications of incomplete dominance&mdash;Why after the first generation only half the children may show the dominant
+character&mdash;Eye-color in man&mdash;Hair-color&mdash;Hair-shape&mdash;Irregularities&mdash;Digital malformations&mdash;Eye defects&mdash;Other defects inherited
+as dominants&mdash;Recessive conditions more difficult to deal with&mdash;Albinism&mdash;Other recessive conditions in man&mdash;Breeding out defects&mdash;Other
+inheritable conditions in man.</td></tr>
+<tr><td>&nbsp;</td></tr>
+<tr><td align="right"><a href="#CHAPTER_V">V</a></td>
+    <td align="center"><span class="smcap">Are Modifications Acquired Directly by the Body Inherited?</span></td>
+    <td align="right"><a href="#Page_121">121</a></td></tr>
+<tr><td>&nbsp;</td><td class="summary">Which new characters are inherited?&mdash;Examples of somatic modifications&mdash;Use and disuse&mdash;The problem
+stated&mdash;Special conditions in mammals&mdash;Three fundamental questions&mdash;External influences may directly affect the germ-cells&mdash;Such effects
+improbable in warm-blooded animals&mdash;Poisons may affect the germ-plasm&mdash;How can somatic modifications be registered in germ-cells?&mdash;Persistence of Mendelian
+factors argues against such a mode of inheritance&mdash;Experiments on insects&mdash;On plants&mdash;On vertebrates&mdash;Epilepsy in guinea-pigs&mdash;Effects
+of mutilations not inherited&mdash;Transplantation of gonads&mdash;Effects of body on germ, general not specific&mdash;Certain characters inexplicable
+as inherited somatic acquirements&mdash;Neuter insects&mdash;Origin of new characters in germinal variation&mdash;Sexual reproduction in relation
+to new characters&mdash;Many features of an organism characterized by utility&mdash;Germinal variation a simpler and more inclusive explanation&mdash;Analysis
+of cases&mdash;Effects of training&mdash;Instincts&mdash;Disease&mdash;Reappearance not necessarily inheritance&mdash;Prenatal infection not inheritance&mdash;Inheritance
+of a predisposition not inheritance of a disease&mdash;Tuberculosis&mdash;Two individuals of tubercular stock should not marry&mdash;Special
+susceptibility less of a factor in many diseases&mdash;Deaf-mutism&mdash;Gout&mdash;Nervous and mental diseases&mdash;Other disorders which have
+hereditary aspects&mdash;Induced immunity not inherited&mdash;Social, ethical and educational significance of non-inheritance of somatic modifications&mdash;No
+cause for discouragement&mdash;Improved environment will help conserve superior strains when they do appear.</td></tr>
+<tr><td>&nbsp;</td></tr>
+<tr><td align="right"><a href="#CHAPTER_VI">VI</a></td>
+    <td align="center"><span class="smcap">Prenatal Influences</span></td>
+    <td align="right"><a href="#Page_159">159</a></td></tr>
+<tr><td>&nbsp;</td><td class="summary">All that a child possesses at birth not necessarily hereditary&mdash;The myth of maternal impressions&mdash;Injurious
+prenatal influences&mdash;Lead poisoning&mdash;The expectant mother should have rest&mdash;Too short intervals between children&mdash;Expectant mothers
+neglected&mdash;Alcoholism&mdash;Unreliability of most data&mdash;Alcohol a germinal and fetal poison&mdash;Various views of specialists on the effects of
+alcoholism on progeny&mdash;The affinity of alcohol for germinal tissue&mdash;Innate degeneracy versus the effects of alcohol&mdash;Experimental alcoholism
+in lower animals&mdash;Further remarks on the situation in man&mdash;Much inebriety in man due to defective nervous constitution&mdash;Factors to be reckoned with
+in the study of alcoholism&mdash;Venereal diseases&mdash;The seriousness of the situation&mdash;Infantile blindness&mdash;Syphilis&mdash;Some of the effects&mdash;A blood
+test&mdash;Many syphilitics married&mdash;Why permit existing conditions to continue?&mdash;Ante-nuptial medical inspection&mdash;The perils of venereal disease
+must be prevented at any cost&mdash;Bad environment can wreck good germ-plasm.</td></tr>
+<tr><td>&nbsp;</td></tr>
+<tr><td align="right"><a href="#CHAPTER_VII">VII</a></td>
+    <td align="center"><span class="smcap">Responsibility for Conduct</span></td>
+    <td align="right"><a href="#Page_195">195</a></td></tr>
+<tr><td>&nbsp;</td><td class="summary">All mental process accompanied by neural process&mdash;Gradations in nervous response from lower organisms to man&mdash;Behavior of many
+animals often an automatic adjustment to simple external agents&mdash;Tropisms&mdash;Certain apparently complex volitions probably only tropisms&mdash;Complicating
+factors&mdash;Many tropic responses apparently purposeful&mdash;Tropisms grade into reflex actions and instincts&mdash;Adjustability of instincts
+opens the way for intelligent behavior&mdash;Modification of habits possible in lower animals&mdash;Some lower vertebrates profit by
+experience&mdash;Rational behavior&mdash;Conceptual thought probably an outgrowth of simpler psychic states&mdash;The capacity for alternative action
+in higher animals&mdash;The elemental units of the nervous system are the same in lower and higher animals&mdash;Neuron theory&mdash;Establishment
+of pathways through the nervous system&mdash;Characteristic arrangements of nerve cells subject to inheritance&mdash;Different parts of the cortex
+yield different reactions&mdash;Skill acquired in one branch of learning probably not transferred to another branch&mdash;Preponderance of cortex in
+highest animals&mdash;Special fiber tracts in the spinal cord of man and higher apes&mdash;Great complexity in associations and more neurons
+in the brain of man&mdash;The nervous system in the main already staged at the time of birth&mdash;Many pathways of conduction not yet established&mdash;The
+extent of the modifiable zone unknown&mdash;Various possibilities of reaction in the child&mdash;Probable origin of altruistic human conduct&mdash;Training
+in motive necessary&mdash;Actual practise in carrying out projects important&mdash;Interest and difficulty both essential&mdash;The realization
+of certain possibilities of the germ rather than others is subject to control&mdash;We must afford the opportunity and provide the proper
+stimuli for the development of good traits&mdash;Moral responsibility.</td></tr>
+<tr><td>&nbsp;</td></tr>
+<tr><td align="right"><a href="#CHAPTER_VIII">VIII</a></td>
+    <td align="center"><span class="smcap">Mental and Nervous Defects</span></td>
+    <td align="right"><a href="#Page_228">228</a></td></tr>
+<tr><td>&nbsp;</td><td class="summary">Prevalence of insanity&mdash;Imperfect adjustments of the brain mechanism inheritable&mdash;Many mental defectives
+married&mdash;Disproportionate increase in number of mental defectives&mdash;Protests voiced by alienists&mdash;Examples of hereditary feeble-mindedness&mdash;Difficult
+to secure accurate data&mdash;Feeble-mindedness and insanity not the same&mdash;Many types of insanity&mdash;Not all insanities of the same eugenical
+significance&mdash;Difficulties of getting genealogies of specific forms of insanity&mdash;Certain forms of insanity seem to behave as Mendelian recessives&mdash;Grades
+of feeble-mindedness&mdash;About two-thirds of feeble-mindedness inherited&mdash;Some results of non-restraint of the feeble-minded&mdash;Not all
+cases of mental deficiency inherited&mdash;Epileptics&mdash;Feeble-mindedness probably a recessive&mdash;Many apparently normal people are carriers of
+neuropathic defects&mdash;Tests for mental deficiency&mdash;The backward child in school&mdash;The exceptionally able child&mdash;Cost of caring for our
+mentally disordered&mdash;Importance of rigid segregation of the feeble-minded&mdash;Importance of early diagnosis of insanity&mdash;Opinion of competent
+psychiatrists essential&mdash;Some insanities not hereditary&mdash;Importance of heredity in insanity not appreciated.</td></tr>
+<tr><td>&nbsp;</td></tr>
+<tr><td align="right"><a href="#CHAPTER_IX">IX</a></td>
+    <td align="center"><span class="smcap">Crime and Delinquency</span></td>
+    <td align="right"><a href="#Page_263">263</a></td></tr>
+<tr><td>&nbsp;</td><td class="summary">Heredity and environment in this field&mdash;Feeble-mindedness often a factor&mdash;Many delinquent girls mentally
+deficient&mdash;Institutional figures misleading&mdash;Many prisoners mentally subnormal&mdash;Inhibitions necessary to social welfare&mdash;The high-grade moron
+a difficult problem&mdash;Degenerate strains&mdash;Intensification of defects by inbreeding&mdash;Vicious surroundings not a sufficient explanation in degenerate
+stocks&mdash;Not all delinquents defectives&mdash;No special inheritable crime-factor&mdash;What is a born criminal?&mdash;Epileptic criminal especially dangerous&mdash;The
+mental disorders most frequently associated with crime&mdash;Bearing of immigration on crime and delinquency&mdash;Sexual vice&mdash;School instruction
+in sex-hygiene&mdash;Mere knowledge not the crux of the sex problem&mdash;Early training in self-restraint an important preventive of crime
+and delinquency&mdash;Multiplication of delinquent defectives must be prevented.</td></tr>
+<tr><td>&nbsp;</td></tr>
+<tr><td align="right"><a href="#CHAPTER_X">X</a></td>
+    <td align="center"><span class="smcap">Race Betterment Through Heredity</span></td>
+    <td align="right"><a href="#Page_289">289</a></td></tr>
+<tr><td>&nbsp;</td><td class="summary">Questionable charity&mdash;Past protests&mdash;An increasing flood of defectives&mdash;Natural elimination of defectives
+done away with&mdash;Why not prevent our social maladies?&mdash;Eugenics defined&mdash;Improved environment alone will not cure racial degeneracy&mdash;Heredity
+and environment&mdash;Inter-racial marriage&mdash;Human conservation&mdash;Kindness in the long run&mdash;The problem has two phases&mdash;Constructive eugenics must be
+based on education&mdash;Inferior increasing more rapidly than superior stocks&mdash;An unselected population may contain much valuable material&mdash;The
+lack of criteria for judging fitness&mdash;The college graduate&mdash;Native ability, independence and energy eugenically desirable&mdash;Four children
+to each marriage required to maintain a stock&mdash;Factors contributing to low birth-rate in desirable strains&mdash;The educated public must
+be made to realize the situation&mdash;Utilization of family pride as a basis for constructive eugenics&mdash;The tendency for like to marry like&mdash;Public
+opinion as an incentive to action&mdash;Choosing a marriage mate means choosing a parent&mdash;The best eugenic marriage also a love
+match&mdash;The elimination of the grossly unfit urgent&mdash;Suggested remedies&mdash;Inefficacy of laws which forbid marriage of mental defectives&mdash;Systems
+of mating impracticable in the main&mdash;Corrective mating presupposes knowledge of eugenics&mdash;Segregation has many advocates&mdash;Sterilization
+as a eugenic measure&mdash;To what conditions applicable&mdash;In insanity&mdash;In feeble-mindedness&mdash;In cases of epilepsy&mdash;Sterilization
+laws&mdash;Social dangers in vasectomy&mdash;Our present knowledge insufficient&mdash;Sterilization laws on trial&mdash;An educated public sentiment the
+most valuable eugenic agent&mdash;The question of personal liberty&mdash;Education of women in eugenics needed&mdash;Much yet to be done&mdash;A working
+program&mdash;Which shall it be?</td></tr>
+<tr><td>&nbsp;</td></tr>
+<tr><td>&nbsp;</td>
+    <td><span class="smcap">Glossary</span></td>
+    <td align="right"><a href="#Page_343">343</a></td></tr>
+<tr><td>&nbsp;</td></tr>
+<tr><td>&nbsp;</td>
+    <td><span class="smcap">References for Further Reading and Study</span></td>
+    <td align="right"><a href="#Page_355">355</a></td></tr>
+<tr><td>&nbsp;</td></tr>
+<tr><td>&nbsp;</td>
+    <td><span class="smcap">Index</span></td>
+    <td align="right"><a href="#Page_361">361</a></td></tr></table>
+
+
+<p>&nbsp;</p><p>&nbsp;</p>
+<hr style="width: 50%;" /><p><span class="pagenum"><a name="Page_1" id="Page_1">[Pg 1]</a></span></p>
+<p class="center"><span class="giant">BEING WELL-BORN</span></p>
+<p>&nbsp;</p>
+<h2><a name="CHAPTER_I" id="CHAPTER_I"></a>CHAPTER I</h2>
+<p class="title">HEREDITY</p>
+
+
+<p>It is a commonplace fact that offspring tend to resemble their parents. So
+commonplace, indeed, that few stop to wonder at it. No one misunderstands
+us when we say that such and such a young man is &#8220;a chip off the old
+block,&#8221; for that is simply an emphatic way of stating that he resembles
+one or the other of his parents. The same is true of such familiar
+expressions as &#8220;what&#8217;s bred in the bone,&#8221; &#8220;blood will tell,&#8221; and kindred
+catch phrases. All are but recognitions of the same common fact that
+offspring exhibit various characteristics similar to those of their
+progenitors.</p>
+
+<p><b>Blood Heritage.&mdash;</b>To this phenomenon of resemblance in successive
+generations based on ancestry the term heredity is applied. In man, for
+instance, there is a marked tendency toward the reappearance in offspring
+of structures, habits, features, and even personal mannerisms, minute
+physical defects, and intimate mental peculiarities like those possessed
+by their parents or more remote forebears. These personal characteristics
+based on descent from a common source are what we may call the blood
+heritage of the child to discriminate it from a wholly<span class="pagenum"><a name="Page_2" id="Page_2">[Pg 2]</a></span> different kind of
+inheritance, namely, the passing on from one generation to the next of
+such material things as personal property or real estate.</p>
+
+<p><b>Kind Determined by Origin.&mdash;</b>It is inheritance in the sense of community of
+origin that determines whether a given living creature shall be man,
+beast, bird, fish, or what not. A given individual is human because his
+ancestors were human. In addition to this stock supply of human qualities
+he has certain well-marked features which we recognize as characteristics
+of race. That is, if he is of Anglo-Saxon or Italian or Mongolian
+parentage, naturally his various qualities will be Anglo-Saxon, Italian,
+or Mongolian. Still further, he has many distinctive features of mind and
+body that we recognize as family traits and lastly, his personal
+characteristics such as designate him to us as Tom, Harry, or James must
+be added. The latter would include such minuti&aelig; as size and shape of ears,
+nose or hands; complexion; perhaps even certain defects; voice; color of
+eyes; and a thousand other particulars. Although we designate these
+manifold items as individual, they are in reality largely more or less
+duplicates of similar features that occur in one or the other of his
+progenitors, features which he would not have in their existing form but
+for the hereditary relation between him and them.</p>
+
+<p class="poem">&#8220;O Damsel Dorothy! Dorothy Q.!<br />
+Strange is the gift that I owe to you;<br />
+<span style="margin-left: 1em;"><strong><span class="spacer">&#183;</span><span class="spacer">&#183;</span><span class="spacer">&#183;</span><span class="spacer">&#183;</span><span class="spacer">&#183;</span></strong></span><br />
+What if a hundred years ago<br />
+Those close-shut lips had answered &#8216;No,&#8217;<br />
+<span style="margin-left: 1em;"><strong><span class="spacer">&#183;</span><span class="spacer">&#183;</span><span class="spacer">&#183;</span><span class="spacer">&#183;</span><span class="spacer">&#183;</span></strong></span><br />
+<span class="pagenum"><a name="Page_3" id="Page_3">[Pg 3]</a></span>Should I be I, or would it be<br />
+One-tenth another, to nine-tenths me?&#8221;<br />
+<br />
+&#8220;Soft is the breath of a maiden&#8217;s yes;<br />
+Not the light gossamer stirs with less;<br />
+But never a cable that holds so fast<br />
+Through all the battles of wave and blast,<br />
+And never an echo of speech or song<br />
+That lives in the babbling air so long!<br />
+There were tones in the voice that whispered then<br />
+You may hear to-day in a hundred men.&#8221;</p>
+
+<p>When life steps into the world of matter there comes with it a sort of
+physical immortality, so to speak; not of the individual, it is true, but
+of the race. But the important thing to note is that the race is made up,
+not of a succession of wholly unrelated forms, but a continuation of the
+same kind of living organisms, and this sameness is due to the actual
+physical descent of each new individual from a predecessor. In other
+words, any living organism is the kind of organism it is in virtue of its
+hereditary relation to its ancestors.</p>
+
+<p>It is part of the biologist&#8217;s task to seek a material basis, a continuity
+of actual substance, for this continuity of life and form between an
+organism and its offspring. Moreover, inasmuch as the offspring is never
+precisely similar to its progenitors he must determine also what qualities
+are susceptible of transmission and in what measure.</p>
+
+<p><b>Ancestry a Network.&mdash;</b>From the fact that each child has all of the
+ancestors of its mother as well as of its father, arises the great
+complications which are met with in determining the lineage of an
+individual.<span class="pagenum"><a name="Page_4" id="Page_4">[Pg 4]</a></span> A person has two parents, four grandparents, eight great
+grandparents, and thus following out pedigree it is plain to be seen that
+through this process of doubling in each generation, in the course of a
+few centuries one&#8217;s ancestry is apparently enormous. By actual
+computation, according to Professor D. S. Jordan, if we count thirty
+generations back to the Norman invasion of England in 1066, at this ratio
+of duplication, the child of to-day would have had at that time an
+ancestry of 8,598,094,592 persons. But we know that the total number of
+inhabitants in England during the time of William the Conqueror was but a
+small fraction of this enormous aggregate. This means that we shall have
+to modify our inference that a child has twice as many ancestors as its
+parents; a condition which at first sight seems evident, but which is not
+literally true. The fact is that the parents of the child, in all
+probability, have many ancestors in common&mdash;a state of affairs which is
+brought about through the intermarriage of relatives, and this is
+especially frequent among remoter descendants of common progenitors. Time
+after time in genealogy strains of blood have crossed and recrossed until
+it is not improbable that a man of to-day who is of English origin has the
+blood in his veins from every inhabitant of England who lived during the
+time of William the Conqueror and left fruitful descendants. Instead of
+conceiving of ancestry as an ever branching and widening tree-like system
+as it recedes into the past, it is more accurate, therefore, to regard it
+in the light of an elaborate meshwork. The &#8220;family tree&#8221; in reality
+becomes the family net.</p>
+
+<p><span class="pagenum"><a name="Page_5" id="Page_5">[Pg 5]</a></span><b>Ancestry in Royalty.&mdash;</b>The pedigrees of royal families have proved to be of
+much importance in the study of human inheritance, not that royal traits
+are any more heritable than any other, but simply because the records have
+been carefully kept so that they are the most comprehensive and easily
+followed pedigrees available. The netlike weave of ancestry is
+particularly well exemplified in some of these families because of much
+close intermarriage. Their heritage typifies on an intensified scale the
+heritage of the mass of mankind. For example, if we go six generations
+back in the ancestry of Frederick the Great instead of the expected
+sixty-four individual ancestors we find only forty; or in a still more
+closely woven stock, in the Spanish royal line of Don Carlos we find in
+six generations instead of sixty-four individual ancestors, only
+twenty-eight. While the present German emperor might have had four
+thousand ninety-six ancestors in the twelfth generation back, it is
+estimated that owing to intermarriage he probably had only five hundred
+thirty-three.</p>
+
+<p><b>Offspring Derived from One Parent Only.&mdash;</b>So far in our reckoning of
+heredity we have counted elements from both father and mother, and the
+complications which arise from such a double ancestry are manifestly very
+perplexing ones. If we could do away with the elements of sex and find
+offspring that are derived from one parent only, it would seemingly
+simplify our problem very much for we should thus have a direct line of
+descent, free from intermingling. This, in fact, occurs to a greater or
+less extent among lower animals in a number of instances. There may<span class="pagenum"><a name="Page_6" id="Page_6">[Pg 6]</a></span> be
+only female forms for a number of generations and the eggs which they
+produce develop directly into new individuals. Moreover, many of the
+simpler organisms have the power of dividing their bodies into two and
+thus giving rise to two new forms, each of which resembles the parent.
+This shows plainly that we may have inheritance without the appearance of
+any male ancestor at all, hence sex is not always a necessary factor in
+reproduction or heredity. The development of eggs asexually, that is,
+without uniting first with a male cognate, is termed <i>parthenogenesis</i>.
+The ordinary plant louse or aphid which is frequently found upon geraniums
+is a familiar example of an animal which reproduces largely in this way.
+During the summer only the females exist and they are so astonishingly
+fertile that one such aphid and her progeny, supposing none dies, will
+produce one hundred million in the course of five generations. In the last
+broods of the fall, males and females appear and fertile eggs are produced
+which lie dormant through the winter to start the cycle of the next year.
+Again, the eggs of some kinds of animals which normally have to unite with
+a male germ before they develop, can be made to develop by merely treating
+them with chemical solutions. The difference between an offspring derived
+in such a manner, and one which has developed from an egg fertilized by
+the male is that it is made up of characteristics from only one source,
+the maternal.</p>
+
+<p><b>Dual Ancestry an Aid in Studying Heredity.&mdash;</b>Although we have the factors
+of heredity in a more simplified form in the case of asexual
+transmission,<span class="pagenum"><a name="Page_7" id="Page_7">[Pg 7]</a></span> as a matter of fact most of our insight into the problems
+of heredity has been attained from a study of sexually reproducing forms,
+because the very existence of two sets of more or less parallel features
+offers a kind of checking up system by which we can follow a given
+characteristic.</p>
+
+<p><b>Reversion.&mdash;</b>Occasionally, however, plants and animals do not develop the
+complete individuality we might expect, but stop short at or re-attain
+some ancestral stage along the line of descent, and thus come to resemble
+some progenitor perhaps many generations back of their own time. Thus it
+is well known that as regards one or more characteristics a child may
+resemble a grandparent or often some remote ancestor much more closely
+than it does its immediate parent. The reappearance of such ancestral
+traits the student of heredity designates as <i>Reversion</i> or <i>Atavism</i>.</p>
+
+<p>Reversion may occur apparently in any class of plants or animals. It is
+especially pronounced among domesticated forms, which through man&#8217;s
+selection have been produced under more or less artificial conditions. For
+example, among fancy breeds of pigeons, there may be an occasional return
+to the old slaty blue color of the ancestral rock-pigeon, with two dark
+cross-bars on the wings, from which all modern breeds have been derived.
+This is almost sure to happen if the fancy varieties are inter-crossed for
+two or three generations. Another example of reversion frequently cited is
+the occasional reappearance in domestic poultry of the reddish or brownish
+color pattern of the ancestral jungle-fowl to which, among<span class="pagenum"><a name="Page_8" id="Page_8">[Pg 8]</a></span> modern forms,
+the Indian game seems most nearly related in color. Still another example
+is the cross-bars or stripes occasionally to be seen on the forelegs of
+colts, particularly mules, reminiscent of the extinct wild progenitors
+which were supposedly striped.</p>
+
+<p>Fig. 1, <a href="#Page_9">p. 9</a>, is a picture of a hybrid between the common fowl and the
+guinea-fowl. The chevron-like markings on certain feathers show a
+reversion to a type of color pattern that is prevalent among both the
+primitive pheasants (the domestic chicken is a pheasant) and the primitive
+guinea-fowls. Although the common spotted guinea-fowl may be crossed with
+a black chicken which shows no trace of barring, nevertheless the hybrid
+offspring are likely to bear a chevron-like pattern such as that shown in
+the picture.</p>
+
+<p>There has been much quibbling over the relative meanings of reversion and
+atavism. The general idea, whichever term we use, is that there is a
+&#8220;throwing back&#8221; in a noticeable degree through inheritance to some
+ancestral condition beyond the immediate parents. A few recent authors
+have taken the term atavism in a restricted sense and use it to signify
+specifically those not uncommon cases in which a particular character of
+an offspring resembles the corresponding character of a grandparent
+instead of a parent. Such, for example, as the blue eye-color of a child
+with brown-eyed parents, each of whom in turn has had a blue-eyed parent.
+The tendency of other authors is to abandon the term entirely because of
+the diversity of meaning that has been attached to it in the past.</p>
+
+<p>&nbsp;<span class="pagenum"><a name="Page_9" id="Page_9">[Pg 9]</a></span></p>
+<div class="figcenter"><img src="images/img01.jpg" alt="" /></div>
+<p class="center"><span class="smcap">Fig. 1</span></p>
+<p class="descrip">Hybrid between the guinea-fowl and the common fowl,showing in many
+feathers reversion to a primitive chevron-like barring.</p>
+<p>&nbsp;</p>
+
+<p>Certain classes of so-called reversions, such as the case of the eye-color
+just cited, are readily explicable on Mendelian principles as we shall see
+in a later chapter, but probably not all kinds of phenomena described as
+reversion can be so explained. For example, some seem to be cases of
+suppressed development. The word reversion, indeed, must be looked on<span class="pagenum"><a name="Page_10" id="Page_10">[Pg 10]</a></span> as
+a convenient descriptive term rather than as the name of a single specific
+condition.</p>
+
+<p><b>Telegony.&mdash;</b>There is yet a wide-spread belief in the supposed influence of
+an earlier sire on offspring born by the same mother to a later and
+different sire. This alleged phenomenon is termed <i>telegony</i>. For example,
+many dog-breeders assert that if a thoroughbred bitch has ever had pups by
+a mongrel father, her later offspring, although sired by a thoroughbred,
+will show taints of the former mongrel mating. In such cases the female is
+believed to be ruined for breeding purposes. Other supposed instances of
+such influences have been cited among horses, cattle, sheep, pigs, cats,
+birds, pets of various kinds and even men. The historic case most
+frequently quoted is that of Lord Morton&#8217;s mare which bore a hybrid colt
+when bred to a quagga, a striped zebra-like animal now extinct. In later
+years the same mare bore two colts, sired by a black Arabian horse. Both
+colts showed stripes on the neck and other parts of the body, particularly
+on the legs. It was inferred that this striping was a sort of after effect
+of the earlier breeding with the quagga. In recent times, however,
+Professor Ewart has repeated the experiment a number of times with
+different mares using a Burchell zebra as the test sire. Although his
+experiments have been devised so as to conduce in every way possible to
+telegony his results have been negative. Moreover, it has been pointed out
+that the stripes on the legs of the two foals alleged to show telegony
+could not have been derived from the quagga sire for, unlike zebras,
+quaggas did not have their legs striped. Furthermore<span class="pagenum"><a name="Page_11" id="Page_11">[Pg 11]</a></span> it is known that the
+occurrence of dark brown stripes on the neck, withers and legs of ordinary
+colts is not uncommon, some cases of which have exhibited more zebra-like
+markings than those of the colts from Lord Morton&#8217;s mare. It seems much
+more probable, therefore, that the alleged instances are merely cases of
+ordinary reversion to the striped ancestral color pattern which probably
+characterized the wild progenitors of the domesticated horse.</p>
+
+<p>Various experiments on guinea-pigs, horses, mice and other forms,
+especially devised to test out this alleged after-influence of an earlier
+sire, have all proved negative and the general belief of the biologist
+to-day is that telegony is a myth.</p>
+
+<p><b>Prenatal Influences Apart from Heredity.&mdash;</b>In discussing the problems of
+heredity it is necessary to consider also the possibilities of external
+influences apart from lineage which may affect offspring through either
+parent. Although modifications derived directly by the parent, and
+prenatal influences in general, are of extremely doubtful value as of
+permanent inheritable significance, nevertheless they must be reckoned
+with in any inventory of a child&#8217;s endowment at birth. Impaired vitality
+on the part of the mother, bad nutrition and physical vicissitudes of
+various kinds all enter as factors in the birthright of the child, who,
+moreover, may bear in its veins slumbering poisons from some progenitor
+who has handed on blood taints not properly attributable to heredity. Of
+such importance is this kind of influence to the welfare of the immediate
+child that it will be necessary to discuss it in considerable detail in a
+later chapter.</p>
+
+<p><span class="pagenum"><a name="Page_12" id="Page_12">[Pg 12]</a></span><b>Parent Body and Germ Not Identical.&mdash;</b>Inasmuch as each new individual
+appears to arise from material derived from its parent, taking the
+evidence at its face value one might suppose that any peculiarity of
+organization called forth in the living substance of the parent would
+naturally be repeated in the offspring, but a closer study of the
+developing organism from its first inception to maturity shows this to be
+probably a wrong conclusion. The parent-body and the reproductive
+substance contained in that body are by no means identical. It becomes an
+important question to decide, in fact, how much effect, if any, either
+permanent or temporary, the parent-body really has on the germ.</p>
+
+<p>A given fertile germ (Fig. 2, <a href="#Page_13">p. 13</a>) gives rise by a succession of
+divisions to a body which we call the individual, but such a germ also
+gives rise to a series of new germ-cells which reside in that individual,
+and it is these germ-cells, not something derived from the body, that pass
+on the determiners of distinguishing features or qualities from generation
+to generation. It is only by grasping the significance of this fact that
+we can understand how in certain cases a totally different set of
+characters may appear in an offspring than those manifested in either
+parent.</p>
+
+<p><b>An Hereditary Character Defined.&mdash;</b>By a <i>character</i>, in discussions in
+heredity, is meant simply a trait, feature or other characteristic of an
+organism. Where we can pick out a single definable characteristic which
+acts as a unit in heredity, for greater accuracy we term it a
+<i>unit-character</i>. Many traits are known to be inherited on a unit basis or
+are capable of being<span class="pagenum"><a name="Page_13" id="Page_13">[Pg 13]</a></span> analyzed into factors which are so inherited. These
+unit-characters are in large measure inherited independently of one
+another apparently, although cases of characters inherited as a unit along
+with other characters are known.</p>
+
+<p><b>Hereditary Mingling a Mosaic Rather Than a Blend.&mdash;</b>The independence of
+unit-characters in inheritance leads us to the important conclusion that
+the mingling of two lines of ancestry into a new individual is in no sense
+bringing them into the &#8220;melting pot,&#8221; as it has been picturesquely
+expressed, but it is rather to be regarded as the mingling of two mosaics,
+each particle of which retains its own individuality, and which, even if
+overshadowed in a given generation, may nevertheless manifest its
+qualities undimmed in later generations when conditions favorable to its
+expression transpire.</p>
+
+<p>&nbsp;</p>
+<div class="figcenter"><img src="images/img02.jpg" alt="" /></div>
+<p class="center"><span class="smcap">Fig. 2</span></p>
+<p class="descrip">Diagram illustrating germinal continuity. Through a series of divisions a
+germ-cell gives rise to a body or a soma and to new germ-cells. The
+latter, not the body, give rise in turn to the next generation.</p>
+<p>&nbsp;</p>
+
+<p><b>Determiners of Characters, Not Characters Themselves, Transmitted.&mdash;</b>The
+fact should be thoroughly understood that the actual thing which is
+transmitted by means of the germ in inheritance is not the character
+itself, but something which will <i>determine</i> the<span class="pagenum"><a name="Page_14" id="Page_14">[Pg 14]</a></span> character in the
+offspring. It is important to remember this, for often these
+<i>determiners</i>, as they are called, may lie unexpressed for one or more
+generations and may become manifest only in later descendants. The truth
+of the matter is, the child does not inherit its characters from
+corresponding characters in the parent-body, but parent and child are
+alike because they are both products of the same line of germ-plasm, both
+are chips from the same old block.</p>
+
+
+<p>&nbsp;</p>
+<p class="center">METHODS OF STUDYING HEREDITY</p>
+
+<p>Before entering into details it will be well to get some idea of the
+methods which are commonly employed in arriving at conclusions in the
+field of heredity. Some of these are extremely complex and all that we can
+do in an elementary presentation is to get a glimpse of the procedures.</p>
+
+<p><b>Our Knowledge of Heredity Derived Along Three Lines.&mdash;</b>Our modern
+conceptions of heredity have been derived mainly from three distinct lines
+of investigation: First, from the study of embryology, in which the
+biologist concerns himself with the genesis of the various parts of the
+individual, and the mechanism of the germs which convey the actual
+materials from which these parts spring; second, through experimental
+breeding of plants and animals to compare particular traits or features in
+successive generations; and third, through the statistical treatment of
+observations or measurements of a large number of parents and their
+offspring with reference to a given characteristic in order to determine
+the average <span class="pagenum"><a name="Page_15" id="Page_15">[Pg 15]</a></span>extent of resemblance between parents and children in that
+particular respect.</p>
+
+<p><b>The Method of Experimental Breeding.&mdash;</b>A tremendous impetus was given to
+the method of experimental breeding when it was realized that we can
+itemize many of the parts or traits of an organism into entities which are
+inherited independently one of another. Such traits, or as we have already
+termed them, unit-characters, may be not only independently heritable but
+independently variable as well. The experimental method seeks to isolate
+and trace through successive generations the separate factors which
+determine the individual unit-characters of the organism. In this attempt
+cross-breeding is resorted to. Forms which differ in one or more respects
+are mated and the progeny studied. Next these offspring are mated with
+others of their own kind or mated back with the respective parent types.
+In this way the behavior of a particular character may often be followed
+and the germinal constitutions of the individuals concerned can be
+formulated with reference to it. Inasmuch as we shall give much
+consideration to this method in the chapter on Mendelism we need not
+consider it further here.</p>
+
+<p><b>The Statistical Method.&mdash;</b>The statistical method seeks to obtain large
+bodies of facts and to deal with evidence as it appears through
+mathematical analysis of these facts. The attempt of its followers is to
+treat quantitatively all biological processes with which it is concerned.
+Historically Sir Francis Galton was the first to make any considerable
+application of statistical methods to the problems of heredity and
+variation. In<span class="pagenum"><a name="Page_16" id="Page_16">[Pg 16]</a></span> his attempts to determine the extent of resemblance between
+relatives of different degree as regards bodily, mental and temperamental
+traits, he devised new methods of statistical analysis which constitute
+the basis of modern statistical biology, or <i>biometry</i> as it is termed by
+its votaries. Professor Karl Pearson in particular has extended and
+perfected the mathematical methods of this field and stands to-day as
+perhaps its most representative exponent. The system is in the main based
+on the calculus of probability. The methods often are highly specialized,
+requiring the use of higher mathematics, and are therefore only at the
+command of specially trained workers.</p>
+
+<p>Just as insurance companies can tell us the probable length of human life
+in a given social group, since although uncertain in any particular case,
+it is reducible in mass to a predictable constant, so the biometrician
+with even greater precision because of his improved methods can often,
+when a large number of cases are concerned, give us the intensity of
+ancestral influence with reference to particular characters.</p>
+
+<p>For example, it is clear that by measuring a large number of adult human
+beings one can compute the average height or determine the height which
+will fit the greatest number. There will be some individuals below and
+some above it, but the greater the divergence from this standard height
+the fewer will be the individuals concerned.</p>
+
+<p>Galton compared the heights of 204 normal English parents and their 928
+adult offspring. In order to equalize the measurements of men and women he
+found he had to multiply each female height by 1.08.<span class="pagenum"><a name="Page_17" id="Page_17">[Pg 17]</a></span> Then, to take both
+parents into account when comparing height of parents to that of children
+he added the height of the father to the proportionately augmented height
+of the mother and divided by two, thus securing the height of what he
+termed the &#8220;mid-parent.&#8221; He found that the mid-parental heights of his
+subjects ranged from 64.5 to 72.5 inches, and that the general <i>mode</i> was
+about 68.5 inches. It should be mentioned that the <i>mode</i>, in a given
+population, represents the group containing the largest number of
+individuals of one kind; it may or may not coincide with the average. The
+children of all mid-parents having a given height were measured next and
+tabulated with reference to these mid-parents. The results of Galton&#8217;s
+measurements may be expressed simply as follows:</p>
+
+<table border="0" cellpadding="0" cellspacing="0" summary="table">
+<tr><td colspan="5" class="btr">&nbsp;</td>
+    <td class="btr" align="center">MODE</td>
+    <td class="bt" colspan="4">&nbsp;</td></tr>
+<tr><td class="btr">Height of mid-parent in inches</td>
+    <td class="btr" align="center">64.5</td>
+    <td class="btr" align="center">65.5</td>
+    <td class="btr" align="center">66.5</td>
+    <td class="btr" align="center">67.5</td>
+    <td class="btr" align="center">68.5</td>
+    <td class="btr" align="center">69.5</td>
+    <td class="btr" align="center">70.5</td>
+    <td class="btr" align="center">71.5</td>
+    <td class="bt" align="center">72.5</td></tr>
+<tr><td class="bbr">Average height of offspring</td>
+    <td class="bbr" align="center">65.8</td>
+    <td class="bbr" align="center">66.7</td>
+    <td class="bbr" align="center">67.2</td>
+    <td class="bbr" align="center">67.6</td>
+    <td class="bbr" align="center">68.3</td>
+    <td class="bbr" align="center">68.9</td>
+    <td class="bbr" align="center">69.5</td>
+    <td class="bbr" align="center">69.9</td>
+    <td class="bb" align="center">72.2</td></tr></table>
+
+<p><b>The Law of Regression.&mdash;</b>It is plain from this table that the offspring of
+short mid-parents tend to be under average or modal height though not so
+far below as their parents. Likewise children of tall parents tend to be
+tall but less tall than their parents. This fact illustrates what is known
+as Galton&#8217;s <i>law of regression</i>; namely, that if parents in a given
+population diverge a certain amount from the mode of the population as a
+whole, their children, while tending to<span class="pagenum"><a name="Page_18" id="Page_18">[Pg 18]</a></span> resemble them, will diverge less
+from this mode. It is clear that the extent of regression is an inverse
+measure of the intensity of inheritance from the immediate parents; if the
+deviation of the offspring from the general mode were nearly as great as
+that of their parents then the intensity of the inheritance must be high;
+if but slight&mdash;that is, if the offspring regressed nearly to the
+mode&mdash;then the intensity of the inheritance must be ranked as low. In the
+example in question it must be ranked as relatively high. Computations
+show that as regards stature the fraction two-thirds represents
+approximately the amount of resemblance between the two generations where
+both parents are considered.</p>
+
+<p><b>Correlations Between Parents and Offspring.&mdash;</b>In modern researches the
+conception of mid-parent and mid-grandparent as utilized by Galton has
+been largely abandoned. It has been found more convenient as well as more
+accurate to keep the measurements of the two parents separate and to deal
+with correlations between fathers and sons, fathers and daughters, mothers
+and sons, mothers and daughters, brother and brother, etc. Professor
+Pearson and his pupils have found for a number of characters that the
+correlation between either parent and children, whether sons or daughters,
+is relatively close. The correlation between brother and brother, sister
+and sister, and brother and sister, usually ranges a little higher than
+the corresponding relation between parents and children.</p>
+
+<p><b>The Biometrical Method, Statistical, Not Physiological.&mdash;</b>While biometry
+may in certain cases go far toward showing us the average intensity of
+the<span class="pagenum"><a name="Page_19" id="Page_19">[Pg 19]</a></span> inheritance of certain characters it can not replace the method of
+the experimental breeder which deals with particular characters in
+individual pedigrees. It must be borne in mind that the biometrical method
+is a statistical and not a physiological one and that it is applicable
+only when large numbers of individuals are considered in mass. It is most
+valuable in cases where we are unable sharply to define single characters,
+due probably to the concurrent action of a number of independent causes,
+or where experiment is impossible so that we have to depend solely on
+numerical data gained by observation.</p>
+
+<p><b>Mental Qualities Inheritable.&mdash;</b>Galton showed by this method long ago, and
+Pearson and his school have extended and more clearly established the
+work, that exceptional mental qualities tend to be inherited. While on the
+average the children of exceptional parents tend to be less exceptional
+than their parents, still they are far more likely to be exceptional than
+are the children of average parents. By this method Professor Pearson has
+shown that such mental and temperamental attributes as ability, vivacity,
+conscientiousness, temper, popularity, handwriting, etc., are as
+essentially determined as are physical features through the hereditary
+endowment.</p>
+
+
+
+<p>&nbsp;</p><p>&nbsp;</p>
+<hr style="width: 50%;" />
+<p><span class="pagenum"><a name="Page_20" id="Page_20">[Pg 20]</a></span></p>
+<h2><a name="CHAPTER_II" id="CHAPTER_II"></a>CHAPTER II</h2>
+<p class="title">THE BEARERS OF THE HERITAGE</p>
+
+
+<p>Before we can make any detailed analysis of the inheritance of characters
+we should have some general idea of the physical structure of animals and
+particularly some familiarity with the development of an individual from
+the egg, as well as some knowledge of the nature of the germ-cells.</p>
+
+<p><b>The Cell the Unit of Structure.&mdash;</b>If we examine one of the higher animals,
+as, for example, the horse, the dog, or man, we find that it is made up of
+a large number of constituents, such as bones, muscles, nervous elements,
+blood and other tissues. Each kind of tissue is composed of a number of
+living units, ordinarily microscopic in size, which are known as cells. A
+careful examination of various cells reveals that although they may differ
+greatly in size, shape and minor details, they all alike possess certain
+well-marked characteristics. Each when reduced to its fundamental form is
+seen to consist of a small mass of living matter termed protoplasm in
+which may usually be distinguished two regions&mdash;the cell-body or
+<i>cytoplasm</i>, and the <i>nucleus</i> (Fig. 3, <a href="#Page_21">p. 21</a>). Any cell, whether it be of
+the brain, of the liver, or from any organ of an animal or plant, has this
+same fundamental structure. In addition, a limiting membrane or wall of
+some kind is generally present, although it is not a necessary constituent
+of all cells.</p>
+
+<p>&nbsp;<span class="pagenum"><a name="Page_21" id="Page_21">[Pg 21]</a></span></p>
+<div class="figcenter"><img src="images/img03.jpg" alt="" /></div>
+<p class="center"><span class="smcap">Fig. 3</span></p>
+<p class="center">Diagram of a cell showing various parts.</p>
+<p>&nbsp;</p>
+
+<p><b>Unicellular Organisms.&mdash;</b>While such a structure as a tree or a horse is
+composed of countless millions of cells, on the other hand numerous
+organisms, both plant and animal, exist which consist of only one cell.
+Yet this cell is just as characteristically a cell as are<span class="pagenum"><a name="Page_22" id="Page_22">[Pg 22]</a></span> the components
+of a complex animal or plant. It has the necessary parts, the cell body
+and the nucleus. Moreover it exhibits all of the fundamental activities of
+life, though in a simplified form, that a complex higher organism does.</p>
+
+<p><b>Importance of Cell-Theory.&mdash;</b>This discovery that every living thing is a
+single cell or an aggregation of cooperating cells and cell-products is
+one of our most important biological generalizations because it has
+brought such a wide range of phenomena under a common point of view. In
+the first place, the structure of both plants and animals is reducible to
+a common fundamental unit of organization. Moreover, both physiological
+and pathological phenomena are more readily understood since we recognize
+that the functions of the body in health or disease are in large measure
+the result of the activities of the individual cells of the functioning
+part. Then again, the problems of embryological development have become
+much more sharply defined since it could be shown that the egg is a single
+cell and that it is through a series of divisions of this cell and
+subsequent changes in the new cells thus formed that the new organism is
+built up. And lastly, the problem of hereditary transmission has been
+rendered more definite and approachable by the discovery that the male
+germ is likewise a single cell, that fertilization of the egg is therefore
+the union of two cells, and that in consequence the mechanism of
+inheritance must be stowed away somehow in these two cells.</p>
+
+<p><b>Heredity in Unicellular Forms.&mdash;</b>In unicellular animals one can readily see
+how it is possible for an<span class="pagenum"><a name="Page_23" id="Page_23">[Pg 23]</a></span> individual always to give rise to its own kind.
+One of the simplest of the single-celled animals is the <i>Ameba</i> (Fig. 4,
+<a href="#Page_24">p. 24</a>).</p>
+
+<p>The ameba eats and grows as do other animals. Sooner or later it reaches a
+size beyond which it can not increase advantageously, yet it is
+continuously taking in new food material which stimulates it to further
+growth. Here then is a problem. The ameba solves this difficulty by
+dividing to form two ameb&aelig;. Such a division is illustrated in Fig. 4, <a href="#Page_24">p.24</a>.
+First the nucleus divides, then the cell-body. When the two new ameb&aelig;
+separate completely each renews the occupation of eating and growing. But
+what has become of the parent? Here, where once existed a large adult
+ameba are two young ameb&aelig;. The parent individual as such has disappeared,
+yet there has been no death, for we have simply two bits of living jelly
+in place of one. They will in turn repeat the same process, so will their
+offspring, and thus, barring accident, this growth and reproduction, or
+overgrowth as we may regard it, may go on forever, as far as we know. Here
+the problem of heredity, or the resemblance of offspring to parent, is not
+a very complicated one. The substance of the cell-body and cell-nucleus
+divides into two similar halves, so that each descendant has the substance
+of the parent in its own body, only it has but half as much. It differs
+from the parent, not in quality or kind, but in size.</p>
+
+<p>&nbsp;<span class="pagenum"><a name="Page_24" id="Page_24">[Pg 24]</a></span></p>
+<div class="figcenter"><img src="images/img04.jpg" alt="" /></div>
+<p class="center"><span class="smcap">Fig. 4</span></p>
+<p class="descrip">Six successive stages in the division of <i>Ameba polypodia</i> (after
+Schulze). The nucleus is seen as a dark spot in the interior.</p>
+<p>&nbsp;</p>
+
+<p><b>Reproduction and Heredity in Colonial Protozoa.&mdash;</b>There are enormous
+numbers of these single-celled animals existing in all parts of the world.
+Some are simple like the ameba, others are very complex in structure.
+Many, after division, move apart and pursue wholly independent courses of
+existence. On the other hand we find a modification appearing in some
+which is of the greatest importance. After division instead of moving
+apart the two cells may remain side<span class="pagenum"><a name="Page_25" id="Page_25">[Pg 25]</a></span> by side and divide further to form
+two more, these in turn may divide and thus the process goes on until
+there is formed what is known as a colony. Each cell of such a colony
+resembles the original ancestral cell because each is a part of the actual
+substance of that cell. As in the ameba, the first two cells are the
+ancestral cell done up in two separate packets, and thus finally the full
+quota of cells must be so many separate packets of the same kind of
+material. Inasmuch as each is but a repetition of its original ancestor,
+it can, and at times does, produce a colony of the same kind as that
+ancestor produced.</p>
+
+<p><b>Conjugation.&mdash;</b>At longer or shorter intervals, however, we find that two
+individuals, on the disruption of the old colony, instead of continuing
+the routine of establishing new colonies through a series of cell
+divisions, very radically alter their behavior. They unite and fuse into a
+single larger individual. This process is called <i>conjugation</i>. We find it
+occurring even in some species of ameba. The conjugating cells in some
+colonies are alike in size and appearance, in others different.</p>
+
+<p><b>Specialization of Sex-Cells.&mdash;</b>A beautiful sphere-shaped colony known as
+<i>Volvox</i> is to be found occasionally in roadside pools. Depending on the
+species of <i>Volvox</i> to which it belongs, the colony may be made up of from
+a few hundred to several thousand individuals arranged in a single layer
+about the fluid-filled center of the sphere and bound together by a clear
+jelly-like inter-cellular substance. Each individual cell also connects
+with its neighbors by means of thin threads of living matter. One of the
+largest<span class="pagenum"><a name="Page_26" id="Page_26">[Pg 26]</a></span> species is <i>Volvox globator</i>, one edge of which is represented in
+Fig. 5, <a href="#Page_27">p. 27</a>. Mutual pressure of the cells gives them a polygonal shape
+when viewed from the surface. Each cell, with a few exceptions to be noted
+immediately, bears two long flagella, whip-like structures which project
+out into the water. The lashing of these flagella gives the ball a rotary
+motion and thus it moves about. When the colony has reached its adult
+condition and is ready to reproduce itself, certain cells without flagella
+and somewhat larger than the ordinary cells become more rounded in outline
+and increase considerably in size through the acquisition of food
+materials. They are then known as egg cells or ova. Each ovum finally
+enters on a series of cell-divisions forming a mass of smaller and smaller
+cells which gradually assumes the form of a hollow sphere like the parent
+colony. The young colonies thus formed drop into the interior of the
+parent colony to escape later to the outside as independent swimming
+organisms when the old colony dies and disintegrates.</p>
+
+<p><b>The Fertilized Ovum Termed a Zygote.&mdash;</b>After a number of generations of
+such asexual reproduction, sexual reproduction occurs. The ova arise as
+usual. Certain members of the colony, on the other hand, go to the other
+extreme and divide up into bundles of from sixty-four to one hundred
+twenty-eight minute slender cells, each provided with flagella for
+locomotion. When mature these small flagellate cells, now known as
+<i>spermatozoa</i>, escape into the interior of the parent colony and swim
+about actively. Ultimately each ovum is penetrated by a spermatozoon, the
+two cells fuse completely and thus form the single <span class="pagenum"><a name="Page_27" id="Page_27">[Pg 27]</a></span><i>fertilized ovum</i> or
+<i>zygote</i>. The body-cells of the mother colony finally disintegrate. After
+a period of rest each zygote, through a series of cell-divisions, develops
+into an adult Volvox. In some species of Volvox a still further advance is
+seen, in that instead of both kinds of gametes being produced in the same
+colony, the ova may be produced by one colony and the spermatozoa by
+another. Here, then, we have the foreshadowings of two sexes as separate
+individuals, a phenomenon of universal occurrence among the highest forms
+of animal life.</p>
+
+<p>&nbsp;</p>
+<div class="figcenter"><img src="images/img05.jpg" alt="" /></div>
+<p class="center"><span class="smcap">Fig. 5</span></p>
+<p class="descrip"><i>Volvox globator</i> (from Hegner after Oltmanns). Half of a sexually
+reproducing colony: <i>o</i>, eggs; <i>s</i>, spermatozoa.</p>
+<p>&nbsp;</p>
+
+<p><b>Advancement Seen in the Volvox Colony.&mdash;</b>In the Volvox colony there is a
+distinct advance over the conditions met with in various lower protozoan
+colonies in that only certain individuals of the colony<span class="pagenum"><a name="Page_28" id="Page_28">[Pg 28]</a></span> take part in the
+process of reproduction and these individuals are of two distinct types;
+one is a larger, food-laden cell or egg and the other a small, active,
+fertilizing cell. The motile forms are produced in much greater numbers
+than the eggs, plainly because they have to seek the egg and many will
+doubtless perish before this can be accomplished. This disparity in number
+is only a means of insuring fertilization of the egg. The remaining cells
+of the body carry on the ordinary activities of the colony such as
+locomotion and nutrition and have ceased to take any part in the
+production of new colonies.</p>
+
+<p><b>Natural Death Appears With the Establishment of a Body Distinct from the
+Germ.&mdash;</b>Volvox is an organism of unusual interest because in it we see a
+prophecy of what is to come. Although still regarded as a colony of
+single-celled individuals, it represents in reality a transition between
+the whole group of unicellular animals termed protozoa and the many celled
+animals characterized by the possession of distinct tissues, known as
+<i>Metazoa</i>. Moreover, it shows an interesting stage in the establishment of
+a body or <i>soma</i> distinct from special reproductive cells which have taken
+on the function of reproducing the colony. In such colonial forms natural
+death is found appearing for the first time, the reproductive cells alone
+continuing to perpetuate the species. Then again Volvox represents an
+important step in the establishment of sex in the animal kingdom for in
+its sexual reproduction the conjugating cells known as <i>gametes</i> are no
+longer alike in appearance but have become differentiated into definite
+ova and spermatozoa.</p>
+
+<p><span class="pagenum"><a name="Page_29" id="Page_29">[Pg 29]</a></span>In Volvox as in the other organisms which we have studied we find that all
+of the cells including the germ-cells are produced by the repeated
+division of a parent cell, and consequently each must contain the
+characteristic living substance of that parent. Many other forms might be
+cited to illustrate reproduction in single-celled animals, whether free or
+in colonies, but all such cases would be practically but repetitions or
+modifications of those we have already examined.</p>
+
+<p><b>Specialization in Higher Organisms.&mdash;</b>If we pass on to the higher animals
+and plants which are not single cells or colonies of similar cells but
+organisms made up of many different kinds of cells, we find a pronounced
+extension of the phenomenon met with in Volvox. Instead of each cell
+executing independently all of the life relations, certain ones are set
+apart for the performance of certain functions to the exclusion of other
+functions which are carried on by other members of the aggregation. Thus
+the organism as a whole has all the life relations carried on, but, as it
+were, by specialists.</p>
+
+<p><b>Sexual Phenomena in Higher Forms.&mdash;</b>In the reproduction of multicellular
+organisms, one sees likewise but a continuation of the phenomena exhibited
+in Volvox. Ordinarily, each new form is produced by the successive
+divisions of a single germ-cell which in the vast majority of cases has
+conjugated with another germ-cell. In the development of the egg, as the
+divisions proceed, groups of cells become modified for their particular
+work until the entire organism is completed. During development certain
+cells are set apart for reproduction of the form just as they were in<span class="pagenum"><a name="Page_30" id="Page_30">[Pg 30]</a></span>
+Volvox. These two kinds of reproductive cells in multicellular organisms
+are derived ordinarily from two separate individuals known as male and
+female, though there are some exceptions. The main difference between
+these cells which will have to unite to form a single fertile germ-cell,
+is that they have specialized in different directions; one is small and
+active, the other large, food-laden and passive. But with two such
+germ-cells coming as they do from two individuals, one the male, the other
+the female, it is obvious that the actual living substance of which each
+germ is composed will be distinctive of its own parental line and that
+when the germs unite these distinctive factors commingle, hence the
+complications of double ancestry arise.</p>
+
+<p><b>Structure of the Cell.&mdash;</b>Before we can understand certain necessary details
+of the physical mechanism of inheritance we must inquire a little further
+into the finer structure of the cell and into the nature of cell division.
+A typical cell, as it would appear after treatment with various stains
+which bring out the different parts more distinctly, is shown in Fig. 3,
+<a href="#Page_21">p. 21</a>. Typical, not that any particular kind of living cell resembles it
+very closely in appearance, but because it shows in a diagrammatic way the
+essential parts of a cell. In the diagram, there are two well-marked
+regions; a central <i>nucleus</i> and a peripheral cell-body or <i>cytoplasm</i>.
+Other structures are pictured but only a few of them need command our
+attention at present. At one side of the nucleus one observes a small dot
+or granule surrounded by a denser area of cytoplasm. This body is called
+the<span class="pagenum"><a name="Page_31" id="Page_31">[Pg 31]</a></span> <i>centrosome</i>. The nucleus in this instance is bounded by a
+well-marked nuclear membrane and within it are several substances. What
+appear to be threads of a faintly staining material, the <i>linin</i>, traverse
+it in every direction and form an apparent network. The parts on which we
+wish particularly to rivet our attention are the densely stained
+substances scattered along or embedded in the strands of this network in
+irregular granules and patches. This substance is called <i>chromatin</i>. It
+takes its name from the fact that it shows great affinity for certain
+stains and becomes intensely colored by them. This deeply colored portion
+of the cell, the chromatin, is by most biologists regarded as of great
+importance from the standpoint of heredity. One or more larger masses of
+chromatin or chromatin-like material, known as <i>chromatin nucleoli</i>, are
+often present, and not infrequently a small spheroidal body, differing in
+its staining reactions from the chromatin-nucleolus and sometimes called
+the <i>true nucleolus</i>, exists.</p>
+
+<p><b>Cell-Division.&mdash;</b>In the simplest type of cell-division the nucleus first
+constricts in the middle, and finally the two halves separate. This
+separation is followed by a similar constriction and final division of the
+entire cell-body, which results in the production of two new cells. This
+form of cell-division is known as <i>simple</i> or <i>direct division</i>. Such a
+simple division, while found in higher animals, is less frequent and
+apparently much less significant than another type of division which
+involves profound changes and rearrangements of the nuclear contents. The
+latter is termed<span class="pagenum"><a name="Page_32" id="Page_32">[Pg 32]</a></span> <i>mitotic</i> or <i>indirect</i> cell-division. Fig. 6, <a href="#Page_33">p. 33</a>,
+illustrates some of the stages which are passed through in indirect
+cell-division. The centrosome which lies passively at the side of the
+nucleus in the typical cell (Fig. 6<i>a</i>, <a href="#Page_33">p. 33</a>) awakens to activity,
+divides and the two components come to lie at the ends of a fibrous
+spindle. In the meantime, the interior of the nucleus is undergoing a
+transformation. The granules and patches of chromatin begin to flow
+together along the nuclear network and become more and more crowded until
+they take on the appearance of one or more long deeply-stained threads
+wound back and forth in a loose skein in the nucleus (Fig. 6<i>b</i>, <a href="#Page_33">p. 33</a>).
+If we examine this thread closely, in some forms it may be seen to consist
+of a series of deeply-stained chromatin granules packed closely together
+intermingled with the substance of the original nuclear network.</p>
+
+<p>As the preparations for division go on the coil in the nucleus breaks up
+into a number of segments which are designated as <i>chromosomes</i> (Fig.
+6<i>c</i>, <a href="#Page_33">p. 33</a>). The nuclear membrane disappears. The chromosomes and the
+spindle-fibers ultimately become related in such a way that the
+chromosomes come to lie at the equator of the spindle as shown in Fig
+6<i>d</i>, <a href="#Page_33">p. 33</a>. Each chromosome splits lengthwise to form two daughter
+chromosomes which then diverge to pass to the poles of the spindle (Figs.
+6<i>e</i> and <i>f</i>, <a href="#Page_33">p. 33</a>). Thus each end of the spindle comes ultimately to be
+occupied by a set of chromosomes. Moreover each set is a duplicate of the
+other, because the substance of any individual chromosome in one group has
+its counterpart in the other. In fact this whole complicated system of
+indirect division <span class="pagenum"><a name="Page_33" id="Page_33">[Pg 33]</a></span>is regarded by most biologists as a mechanism for
+bringing about the precise halving of the chromosomes.</p>
+
+<p>&nbsp;</p>
+<div class="figcenter"><img src="images/img06.jpg" alt="" /></div>
+<p class="center"><span class="smcap">Fig. 6</span></p>
+
+<p class="descrip">Diagram showing representative stages in mitotic or indirect
+cell-division: <i>a</i>, resting cell with reticular nucleus and single
+centrosome; <i>b</i>, the two new centrosomes formed by division of the old one
+are separating and the nucleus is in the spireme stage; <i>c</i>, the nuclear
+wall has disappeared, the spireme has broken up into six separate
+chromosomes, and the spindle is forming between the two centrosomes; <i>d</i>,
+equatorial plate stage in which the chromosomes occupy the equator of the
+spindle; <i>e</i>, <i>f</i>, each chromosome splits lengthwise and the daughter
+chromosomes thus formed approach their respective poles; <i>g</i>,
+reconstruction of the new nuclei and division of the cell body; <i>h</i>, cell-division completed.</p>
+<p>&nbsp;</p>
+
+<p><span class="pagenum"><a name="Page_34" id="Page_34">[Pg 34]</a></span>The chromosomes of each group at the poles finally fuse and two new
+nuclei, each similar to the original one, are constructed (Figs. 6<i>g</i> and
+<i>h</i>, <a href="#Page_33">p. 33</a>). In the meantime a division of the cell-body is in progress
+which, when completed, results in the formation of two complete new cells.</p>
+
+<p>As all living matter if given suitable food, can convert it into living
+matter of its own kind, there is no difficulty in conceiving how the new
+cell or the chromatin material finally attains to the same bulk that was
+characteristic of the parent cell. In the case of the chromatin, indeed,
+it seems that there is at times a precocious doubling of the ordinary
+amount of material before the actual division occurs.</p>
+
+<p><b>Chromosomes Constant in Number and Appearance.&mdash;</b>With some minor
+exceptions, to be noted later, which increase rather than detract from the
+significance of the facts, the chromosomes are always the same in number
+and appearance in all individuals of a given species of plants or animals.
+That is, every species has a fixed number which regularly recurs in all of
+its cell-divisions. Thus the ordinary cells of the rat, when preparing to
+divide, each display sixteen chromosomes, the frog or the mouse,
+twenty-four, the lily twenty-four, and the maw-worm of the horse only
+four. The chromosomes of different kinds of animals or plants may differ
+very much in appearance. In some they are spherical, in others rod-like,
+filamentous or perhaps of other forms. In some organisms the chromosomes
+of the same nucleus may differ from one<span class="pagenum"><a name="Page_35" id="Page_35">[Pg 35]</a></span> another in size, shape and
+proportions, but if such differences appear at one division they appear at
+others, thus showing that in such cases the differences are constant from
+one generation to the next.</p>
+
+<p><b>Significance of the Chromosomes.&mdash;</b>The question naturally arises as to what
+is the significance of the chromosomes. Why is the accurate adjustment
+which we have noted for their division necessary? The very existence of an
+elaborate mechanism so admirably adapted to their precise halving,
+predisposes one toward the belief that the chromosomes have an important
+function which necessitates the retention of their individuality and their
+equal division. Many biologists accept this along with other evidence as
+indicating that in chromatin we have a substance which is not the same
+throughout, that different regions of the same chromosome have different
+physiological values.</p>
+
+<p>When the cell prepares for divisions, the granules, as we have seen,
+arrange themselves serially into a definite number of strands which we
+have termed chromosomes. Judging from all available evidence, the granules
+are self-propagating units; that is, they can grow and reproduce
+themselves. So that what really happens in mitosis in the splitting of the
+chromosomes is a precise halving of the series of individual granules of
+which each chromosome is constituted, or in other words each granule has
+reproduced itself. Thus each of the two daughter cells presumably gets a
+sample of every kind of chromosomal particle, hence, the two cells are
+qualitatively alike. To use a homely illustration we may picture the
+individual chromosomes to ourselves as so many separate trains of freight
+cars,<span class="pagenum"><a name="Page_36" id="Page_36">[Pg 36]</a></span> each car of which is loaded with different merchandise. Now, if
+every one of the trains could split along its entire length and the
+resulting halves each grow into a train similar to the original, so that
+instead of one there would exist two identical trains, we should have a
+phenomenon analogous to that of a dividing chromosome.</p>
+
+<p><b>Cleavage of the Egg.&mdash;</b>It is through a series of such divisions as these
+that the zygote or fertilized egg-cell builds up the tissues and organs of
+the new organism. The process is technically spoken of as <i>cleavage</i>.
+Cleavage generally begins very shortly after fertilization. The fertile
+egg-cell divides into two, the resulting cells divide again and thus the
+process continues, with an ever-increasing number of cells.</p>
+
+<p><b>Chief Processes Operative in Building the Body.&mdash;</b>Although of much
+interest, space will not permit of a discussion in detail of the building
+up of the special organs and tissues of the body. It must suffice merely
+to mention the four chief processes which are operative. These are, (1)
+infoldings and outfoldings of the various cell complexes; (2)
+multiplication of the component cells; (3) special changes (<i>histological
+differentiation</i>) in groups of cells; and (4) occasionally resorption of
+certain areas of parts.</p>
+
+<p><b>The Origin of the New Germ-Cells.&mdash;</b>On account of the unusual importance
+from the standpoint of inheritance, which attaches to the germ-cells, a
+final word must be said about their origin in the embryo. While the
+evidence is conflicting in some cases, in others it has been well
+established that the germ-cells are set apart very early from the cells
+which are to<span class="pagenum"><a name="Page_37" id="Page_37">[Pg 37]</a></span> differentiate into the ordinary body tissues. Fig. 7<i>A</i>,
+<a href="#Page_38">p. 38</a>, shows a section through the eight-celled stage of <i>Miastor</i>, a fly, in
+which a single large, primordial germ-cell (<i>p. g. c.</i>) has already been
+set apart at one end of the developing embryo. The nuclei of the rest of
+the embryo still lie in a continuous protoplasmic mass which has not yet
+divided up into separate cells. The densely stained nuclei at the opposite
+end of the section are the remnants of nurse-cells which originally
+nourished the egg. Fig. 7<i>B</i>, <a href="#Page_38">p. 38</a>, is a longitudinal section through a
+later stage in the development of <i>Miastor</i>; the primitive germ-cells
+(o&ouml;g) are plainly visible. Still other striking examples might be cited.
+Even in vertebrates the germ-cells may often be detected at a very early
+period.</p>
+
+<p><b>Significance of the Early Setting Apart of the Germ-Cells.&mdash;</b>It is of great
+importance for the reader to grasp the significance of this early setting
+apart of the germ-cells because so much in our future discussion hinges on
+this fact. The truth of the statement made in a previous chapter that the
+body of an individual and the reproductive substance in that body are not
+identical now becomes obvious. For in such cases as those just cited one
+sees the germinal substance which is to carry on the race set aside at an
+early period in a given individual; it takes no part in the formation of
+that individual&#8217;s body, but remains a slumbering mass of potentialities
+which must bide its time to awaken into expression in a subsequent
+generation. Thus an egg does not develop into a body which in turn makes
+new germ-cells, but body and germ-cells are established at the same time,
+the body<span class="pagenum"><a name="Page_38" id="Page_38">[Pg 38]</a></span> harboring and nourishing the germ-cells, but not generating them
+(Fig. 2, <a href="#Page_13">p. 13</a>). The same must be true also in many cases where the
+earliest history of the germ-cells can not be visibly followed, because in
+any event, in all higher animals, they appear long before the embryo is
+mature and must therefore be descendants of the original egg-cell and not
+of the functioning tissues of the mature individual. This need not
+necessarily mean that the germ-cells have remained wholly unmodified or
+that they continue uninfluenced by the conditions which prevail in the
+body, especially in the nutritive blood and lymph stream, although as a
+matter of fact most biologists are extremely skeptical as to the
+probability that influences from the body beyond such general indefinite
+effects as might result from under-nutrition or from poisons carried in
+the blood, modify the intrinsic nature of the germinal substances to any
+measurable extent.</p>
+
+
+<p>&nbsp;</p>
+<div class="figcenter"><img src="images/img07.jpg" alt="" /></div>
+<p class="center"><span class="smcap">Fig. 7</span></p>
+
+<p class="descrip">A&mdash;Germ-cell (<i>p. g. c.</i>) set apart in the eight-celled stage of cleavage
+in <i>Miastor americana</i> (after Hegner). The walls of the remaining seven
+somatic cells have not yet formed though the resting or the dividing (<i>M
+p</i>) nuclei may be seen; <i>c R</i>, chromatin fragments cast off from the
+somatic cells.</p>
+
+<p class="descrip">B&mdash;Section lengthwise of a later embryo of <i>Miastor</i>; the primordial
+egg-cells (<i>o&ouml;g</i><sub>3</sub>) are conspicuous (after Hegner).</p>
+<p>&nbsp;</p>
+
+<p><span class="pagenum"><a name="Page_39" id="Page_39">[Pg 39]</a></span><b>Germinal Continuity.&mdash;</b>The germ-cells are collectively termed the <i>germinal
+protoplasm</i> and it is obvious that as long as any race continues to exist,
+although successive individuals die, some germinal protoplasm is handed on
+from generation to generation without interruption. This is known as the
+theory of <i>germinal continuity</i>. When the organism is ready to reproduce
+its kind the germ-cells awaken to activity, usually undergoing a period of
+multiplication to form more germ-cells before finally passing through a
+process of what is known at <i>maturation</i>, which makes them ready for
+fertilization. The maturation process proper, which consists typically of
+two rapidly succeeding divisions, is preceded by a marked growth in size
+of the individual cells.</p>
+
+<p><b>Individuality of Chromosomes.&mdash;</b>Before we can understand fully the
+significance of the changes which go on during maturation we shall have to
+know more<span class="pagenum"><a name="Page_40" id="Page_40">[Pg 40]</a></span> about the conditions which prevail among the chromosomes of
+cells. As already noted each kind of animal or plant has its own
+characteristic number and types of chromosomes when these appear for
+division by mitosis. In many organisms the chromosomes are so nearly of
+one size as to make it difficult or impossible to be sure of the identity
+of each individual chromosome, but on the other hand, there are some
+organisms known in which the chromosomes of a single nucleus are not of
+the same size and form (Fig. 8, <a href="#Page_41">p. 41</a>). These latter cases enable us to
+determine some very significant facts. Where such differences of shape and
+proportion occur they are constant in each succeeding division so that
+similar chromosomes may be identified each time. Moreover, in all ordinary
+mitotic divisions where the conditions are accurately known, these
+chromosomes of different types are found to be present as pairs of similar
+elements; that is, there are two of each form or size.</p>
+
+<p><b>Pairs of Similar Chromosomes in the Nucleus Because One Chromosome Comes
+from Each Parent.&mdash;</b>When we recall that the original fertilized egg from
+which the individual develops is really formed by the union of two
+gametes, ovum and spermatozoon, and that each gamete, being a true cell,
+must carry its own set of chromosomes, the significance of the pairs of
+similar chromosomes becomes evident; one of each kind has probably been
+contributed by each gamete. This means that the zygote or fertile ovum
+contains double the number of chromosomes possessed by either gamete, and
+that, moreover, each tissue-cell of the new individual will contain this
+dual number. For, as we<span class="pagenum"><a name="Page_41" id="Page_41">[Pg 41]</a></span> have seen, the number of chromosomes is, with
+possibly a few exceptions, constant in the tissue-cells and early
+germ-cells in successive generations of individuals. For this to be true
+it is obvious that in some way the nuclei of the conjugating gametes have
+come to contain only half the usual number. Technically the tissue-cells
+are said to contain the <i>diploid</i> number of chromosomes, the gametes the
+reduced or <i>haploid</i> number.</p>
+
+
+<p>&nbsp;</p>
+<div class="figcenter"><img src="images/img08.jpg" alt="" /></div>
+<p class="center"><span class="smcap">Fig. 8</span></p>
+
+<p class="center">A&mdash;Chromosomes of the mosquito (<i>Culex</i>) after Stevens.</p>
+
+<p class="center">B&mdash;Chromosomes of the fruit-fly (<i>Drosophila</i>) after Metz.</p>
+
+<p class="center">Both of these forms have an unusually small number of chromosomes.</p>
+<p>&nbsp;</p>
+
+<p><b>In Maturation the Number of Chromosomes Is Reduced by One-Half.&mdash;</b>This
+halving, or as it is known, <i>reduction</i> in the number of chromosomes is
+the essential feature of the process of maturation. It is accomplished by
+a modification in the mitotic division in which instead of each chromosome
+splitting lengthwise, as in ordinary mitosis, the chromosomes unite in
+pairs (Fig. 9<i>b</i>, <a href="#Page_42">p. 42</a>), a process known technically as <i>synapsis</i>, and
+then apparently one member of each pair passes entire into one new
+daughter cell,<span class="pagenum"><a name="Page_42" id="Page_42">[Pg 42]</a></span> the other member going to the other daughter cell (Fig.
+9<i>c</i>, <a href="#Page_42">p. 42</a>). In the pairing preliminary to this <i>reduction division</i>,
+leaving out of account certain special cases to be considered later,
+according to the best evidence at our command the union always takes place
+between two chromosomes which match each other in size and appearance.
+Since one of these is believed to be of maternal and the other of
+paternal origin, the ensuing division separates corresponding mates and
+insures that each gamete gets one of each kind of chromosome although it
+appears to be a matter of mere chance whether or not a given cell gets the
+paternal or the maternal representative of that kind.</p>
+
+<p>&nbsp;</p>
+<div class="figcenter"><img src="images/img09.jpg" alt="" /></div>
+<p class="center"><span class="smcap">Fig. 9</span></p>
+
+<p class="descrip">Diagram to illustrate spermatogenesis: <i>a</i>, showing the diploid number of
+chromosomes (six is arbitrarily chosen) as they occur in divisions of
+ordinary cells and spermatogonia; <i>b</i>, the pairing (synapsis) of
+corresponding mates in the primary spermatocyte preparatory to reduction;
+<i>c</i>, each secondary spermatocyte receives three, the haploid number of
+chromosomes; <i>d</i>, division of the secondary spermatocytes to form <i>e</i>,
+spermatids, which transform into <i>f</i>, spermatozoa.</p>
+<p>&nbsp;</p>
+
+<p><span class="pagenum"><a name="Page_43" id="Page_43">[Pg 43]</a></span><b>Maturation of the Sperm-Cell.&mdash;</b>In the maturation of the male gamete the
+germ-cell, now known as a <i>spermatogonium</i>, increases greatly in size to
+become a <i>primary spermatocyte</i>. In each primary spermatocyte the pairing
+of the chromosomes already alluded to occurs as indicated in Fig. 9<i>b</i>,
+<a href="#Page_42">p. 42</a>, where six is taken arbitrarily to indicate the ordinary or <i>diploid</i>
+number of chromosomes, and three the reduced or <i>haploid</i> number. The
+division of the primary spermatocyte gives rise to two <i>secondary
+spermatocytes</i> (<i>c</i>), the paired chromosomes separating in such a way that
+a member of each pair goes to each secondary spermatocyte. Each secondary
+spermatocyte (<i>d</i>) soon divides again into two <i>spermatids</i> (<i>e</i>), but in
+this second division the chromosomes each split lengthwise as in an
+ordinary division so that there is no further reduction. In some forms the
+reduction division occurs in the secondary spermatocytes instead of the
+primary. Each spermatid transforms into a mature spermatozoon (<i>f</i>). The
+spermatozoa of most animals are of linear form, each with a head, a
+middle-piece and a long vibratile tail which is used for locomotion. The
+head consists for the most part of the transformed nucleus and is
+consequently the part which bears the chromosomes.</p>
+
+<p><span class="pagenum"><a name="Page_44" id="Page_44">[Pg 44]</a></span><b>Maturation of the Egg-Cell.&mdash;</b>As regards the behavior of the chromosomes
+the maturation of the ovum parallels that of the sperm-cell. There are not
+so many primordial germ-cells formed and only one out of four of the
+ultimate cells becomes a functional egg. As in maturation of the
+sperm-cell there is a growth period in which <i>o&ouml;gonia</i> enlarge to become
+<i>primary o&ouml;cytes</i> (Fig. 10<i>b</i>, <a href="#Page_45">p. 45</a>). In each primary o&ouml;cyte as in the
+primary spermatocyte the chromosomes pair and two rapidly succeeding
+divisions follow in one of which the typical numerical reduction in the
+chromosomes occurs. A peculiarity in the maturation of the ovum is that
+there is a very unequal division of the cytoplasm in cell division so that
+three of the resulting cells usually termed <i>polar bodies</i> are very small
+and appear like minute buds on the side of the fourth or egg-cell proper.</p>
+
+<p>The scheme of this formation of the polar bodies is indicated in Fig. 10,
+<a href="#Page_45">p. 45</a>. In Fig. 10<i>b</i> the chromosomes are seen paired and ready for the
+first division; that is, for the formation of the first polar body. Figs.
+10<i>c</i>, <i>d</i>, <a href="#Page_45">p. 45</a>, show the giving off of this body. Note that while only
+a small proportion of the cytoplasm passes into this tiny cell, its
+chromatin content is as great as that of the ovum. A second polar body
+(Figs. 10<i>e</i>, <i>f</i>, <a href="#Page_45">p. 45</a>) is formed by the egg, but in this case each
+chromosome splits lengthwise, as in ordinary mitosis, and there is no
+further numerical reduction. In the meantime, typically, a third polar
+body is formed by division of the first. (Stages <i>e</i>, <i>f</i>, <i>g</i>.)</p>
+
+<p><b>Parallel Between the Maturation of Sperm- and Egg-Cell.&mdash;</b>This rather
+complex procedure of the<span class="pagenum"><a name="Page_45" id="Page_45">[Pg 45]</a></span> germ-cells will be rendered more intelligible
+through a careful study of Figs. 9 and 10, <a href="#Page_42">pp. 42</a> and <a href="#Page_45">45</a>,
+and Fig. 11, <a href="#Page_46">p. 46</a>, which indicates the parallel conditions in spermotogenesis and
+o&ouml;genesis.</p>
+
+<p>&nbsp;</p>
+<div class="figcenter"><img src="images/img10.jpg" alt="" /></div>
+<p class="center"><span class="smcap">Fig. 10</span></p>
+
+<p class="descrip">Diagram to illustrate o&ouml;genesis: <i>a</i>, showing the diploid number of
+chromosomes (six is arbitrarily chosen) as they occur in ordinary cells
+and o&ouml;gonia; <i>b</i>, the pairing of corresponding mates preparatory to
+reduction; <i>c</i>, <i>d</i>, reduction division, giving off of first polar body;
+<i>e</i>, egg preparing to give off second polar body, first polar body ready
+for division; <i>f</i>, <i>g</i>, second polar body given off, division of first
+polar body completed. The egg nucleus, now known as the female pronucleus,
+and each body contain the reduced or haploid number of chromosomes.</p>
+<p>&nbsp;</p>
+
+<p>The view now generally held regarding the polar bodies is that they are
+really abortive eggs. They later disappear, taking no part in
+embryo-formation. It can readily be seen how such an unequal division is
+advantageous to the large cell, for it receives all of the<span class="pagenum"><a name="Page_46" id="Page_46">[Pg 46]</a></span> rich store of
+food material that would be distributed among the four cells if all were
+of equal size. This increased amount of food is a favorable provision for
+the forthcoming offspring whose nourishment is thus more thoroughly
+insured.</p>
+
+<p>&nbsp;</p>
+<div class="figcenter"><img src="images/img11tmb.jpg" alt="" /><br />
+<a href="images/img11.jpg"><small>Larger Image</small></a></div>
+<p class="center"><span class="smcap">Fig. 11</span></p>
+
+<p class="descrip">Diagram showing the parallel between maturation of the sperm-cell and maturation of the ovum.</p>
+<p>&nbsp;</p>
+
+<p><span class="pagenum"><a name="Page_47" id="Page_47">[Pg 47]</a></span>On the other hand, all of the sperm-cells develop into complete active
+forms, which, as aforesaid, usually become very much elongated and develop
+a motile organ of some kind. In such cells an accumulation of food to any
+large extent would hinder rather than help them, because it would
+seriously interfere with their activity.</p>
+
+<p><b>Fertilization.&mdash;</b>In fertilization (Fig. 12, <a href="#Page_48">p. 48</a>) the spermatozoon
+penetrates the wall of the ovum and after undergoing considerable
+alteration its nucleus fuses with the nucleus of the egg. In some forms
+only the head (nucleus) and middle-piece enter, the tail being cut off by
+a so-called fertilization membrane which forms at the surface of the egg
+and effectually blocks the entrance of other spermatozoa. Thus normally
+only one spermatozoon unites with an egg. In some forms while several may
+enter the egg only one becomes functional. As soon as the nucleus of the
+spermatozoon, now known as the male <i>pronucleus</i>, reaches the interior of
+the egg, it enlarges and becomes similar in appearance to the female
+<i>pronucleus</i>. It swings around in such a way (Fig. 12<i>b</i>, <a href="#Page_48">p. 48</a>) that the
+middle piece, now transformed into a centrosome, lies between it and the
+female pronucleus. The two pronuclei (<i>c</i>, <i>d</i>, <i>e</i>), each containing the
+reduced number of chromosomes, approach, the centrosome divides, the
+nuclear walls disappear, the typical division spindle forms, and the
+chromosomes of paternal and maternal origin respectively come to lie side
+by side at the equator of the spindle ready for the first division or
+cleavage (<i>f</i>, <i>g</i>). It will be noted that the individual chromosomes do
+not intermingle their substance at this<span class="pagenum"><a name="Page_48" id="Page_48">[Pg 48]</a></span> time, but that each apparently
+retains its own individuality. There is considerable evidence which
+indicates that throughout life the chromosomes contributed by the male
+parent remain distinct from those of the female parent. Inasmuch as each
+germ-cell, after maturation, contains only half the characteristic number
+of chromosomes, the original number is restored in fertilization.</p>
+
+<p>&nbsp;</p>
+<div class="figcenter"><img src="images/img12.jpg" alt="" /></div>
+<p class="center"><span class="smcap">Fig. 12</span></p>
+
+<p class="descrip">Diagram to illustrate fertilization; &#9794;, male pronucleus; &#9792;,
+female pronucleus; observe that the chromosomes of maternal and paternal origin respectively do not fuse.</p>
+<p>&nbsp;</p>
+
+<p><span class="pagenum"><a name="Page_49" id="Page_49">[Pg 49]</a></span><b>Significance of the Behavior of the Chromosomes.&mdash;</b>The question confronts
+us as to what is the significance of this elaborate system which keeps the
+chromosomes of constant size, shape and number; which partitions them so
+accurately in ordinary cell-divisions; and which provides for a reduction
+of their numbers by half in the germ-cell while yet securing that each
+mature gamete gets one of each kind of chromosome. Most biologists look on
+these facts as indicating that the chromosomes are specifically concerned
+in inheritance.</p>
+
+<p>In the first place it is recognized that as regards the definable
+characters which separate individuals of the same species, offspring may
+inherit equally from either parent. And it is a very significant fact that
+while the ovum and spermatozoon are very unequal in size themselves, the
+chromosomes of the two germ-cells are of the same size and number. This
+parity in chromosomal contribution points clearly to the means by which an
+equal number of character-determiners might be conveyed from each parent.
+Moreover it is mainly the nucleus of the sperm-cell in some organisms
+which enters the egg, hence the determiners from the male line must exist
+wholly or largely somewhere in the nucleus. And the bulk of the nucleus in
+the spermatozoon consists of the chromosomes or their products.</p>
+
+<p><b>A Single Set of Chromosomes Derived from One Parent Only Is Sufficient for
+the Production of a Complete Organism.&mdash;</b>That a single or haploid set<span class="pagenum"><a name="Page_50" id="Page_50">[Pg 50]</a></span> of
+chromosomes as seen in the gametes is sufficient contribution of chromatin
+for the production of a complete organism is proved by the fact that the
+unfertilized eggs of various animals (many echinoderms, worms, mollusks,
+and even the frog) may be artificially stimulated to development without
+uniting at all with a spermatozoon. The resulting individual is normal in
+every respect except that instead of the usual diploid number it has only
+the single or haploid number of chromosomes. Its inheritance of course is
+wholly of maternal origin. The converse experiment in echinoderms in which
+a nucleus of male origin (that is, a spermatozoon) has been introduced
+into an egg from which the original nucleus has been removed shows that
+the single set of chromosomes carried by the male gamete is also
+sufficient to cooperate with the egg-cytoplasm in developing a complete
+individual.</p>
+
+<p><b>The Duality of the Body and the Singleness of the Germ.&mdash;</b>Since every
+maternal chromosome in the ordinary cell has an equivalent mate derived
+from the male parent, it follows therefore, supposing the chromosomes do
+have the significance in inheritance attributed to them, that as regards
+the measurable inheritable differences between two individuals, the
+ordinary organism produced through the union of the two germ-cells is,
+potentially at least, dual in nature. On the other hand through the
+process of reduction the gametes are provided with only a single set of
+such representatives. This duality of the body and singleness of the
+mature germ is one of the most striking facts that come to light in
+embryology. How well the facts fit in with the behavior of certain
+hereditary<span class="pagenum"><a name="Page_51" id="Page_51">[Pg 51]</a></span> characters will be seen later in our discussions of Mendelism.</p>
+
+<p><b>The Cytoplasm Not Negligible in Inheritance.&mdash;</b>Just what part is played by
+the cytoplasm in inheritance is not clear, but it is probably by no means
+a negligible one. The cytoplasm of a given organism is just as distinctive
+of the species or of the individual of which it forms a part as are the
+chromosomes. It is well established that neither nucleus nor cytoplasm can
+fully function or even exist long without the other, and neither can alone
+produce the other. They undoubtedly must cooperate in building up the new
+individual, and the cytoplasm of the new individual is predominantly of
+maternal origin. It is obvious that all of the more fundamental characters
+which make up an organism, such, for instance, as make it an animal of a
+certain order or family, as a human being or a dog or a horse, are common
+to both parents, and there is no way of measuring how much of this
+fundamental constitution comes from either parent, since only closely
+related forms will interbreed. In some forms, moreover, the broader
+fundamental features of embryogeny are already established before the
+entrance of the spermatozoon. It is probable therefore that instead of
+asserting that the entire quota of characters which go to make up a
+complete individual are inherited from each parent equally, we are
+justified only in maintaining that this equality is restricted to those
+measurable differences which veneer or top off, as it were, the
+individual. We may infer that in the development of the new being the
+chromosomes of the egg together with those derived from the male work<span class="pagenum"><a name="Page_52" id="Page_52">[Pg 52]</a></span>
+jointly on or with the other germinal contents which are mostly
+cytoplasmic materials of maternal origin.</p>
+
+<p><b>The Chromosomes Possibly Responsible for the Distinctiveness of Given
+Characters.&mdash;</b>It seems probable that in the establishment of certain basic
+features of the organism the cooperation of the cytoplasm with chromatin
+of either maternal or paternal origin might accomplish the same end, but
+that certain distinctive touches are added or come cumulatively into
+expression through influences carried, predominantly at least, in the
+chromatin from one as against the other parent. These last distinctive
+characters of the plant or animal constitute the individual differences of
+such organisms. In this connection it is a significant fact that in young
+hybrids between two distinct species the early stages of development,
+especially as regards symmetry and regional specifications, are
+exclusively or predominantly maternal in character, but the male influence
+becomes more and more apparent as development progresses until the final
+degree of intermediacy is attained.</p>
+
+<p>From the evidence at hand this much seems sure, that the paternal and
+maternal chromosomes respectively carry substances, be they ferments,
+nutritive materials or what not, that are instrumental in giving the final
+parity of personal characters which we observe to be equally heritable
+from either line of ancestry. It is clear that most of the characters of
+an adult organism can not be merely the outcome of any unitary substance
+of the germ. Each is the product of many cooperating factors and for the
+final outcome any one<span class="pagenum"><a name="Page_53" id="Page_53">[Pg 53]</a></span> cooperant is probably just as important in its way
+as any other. The individual characters which we juggle to and fro in our
+breeding experiments seem apexed, as it were, on more fundamental features
+of organic chemical constitution, polarity, regional differentiation, and
+physiological balance, but since such individual characters parallel so
+closely the visible segregations and associations which go on among the
+chromosomes of the germ-cells it would seem that they, at least, are
+represented in the chromosomes by distinctive cooperants which give the
+final touch of specificity to those hereditary characters which can be
+shifted about as units of inheritance.</p>
+
+<p><b>Sex and Heredity.&mdash;</b>Whatever the origin of fertilization may have been in
+the world of life, or whatever its earliest significance, the important
+fact remains that to-day it is unquestionably of very great significance
+in relation to the phenomena of heredity. For in all higher animals, at
+least, offspring may possess some of the characteristics originally
+present in either of two lines of ancestry, and this commingling of such
+possessions is possible only through sexual reproduction. As has already
+been seen, in the pairing of chromosomes previous to reduction, the
+corresponding members of a pair always come together so that in the final
+segregation each gamete is sure to have one of each kind although whether
+a given chromosome of the haploid set is of maternal or paternal origin
+seems to be merely a matter of chance. Thus, for instance, if we
+arbitrarily represent the chromosomes of a given individual by <i>ABC</i>
+<i>abc</i>, and regard <i>A</i>, <i>B</i><span class="pagenum"><a name="Page_54" id="Page_54">[Pg 54]</a></span>
+and <i>C</i> as of paternal and <i>a</i>, <i>b</i> and <i>c</i> as
+of maternal origin, then in synapsis only <i>A</i> and <i>a</i> can pair together,
+<i>B</i> and <i>b</i> and <i>C</i> and <i>c</i>, but each pair operates independently of the
+other so that in the ensuing reduction division either member of a pair
+may get into a cell with either member of the other pairs. That is, the
+line up for division at a given reduction might be any one of the
+following, <span style="font-size: 0.8em;"><sup>ABC</sup></span>&frasl;<span style="font-size: 0.6em;">abc</span>
+<span style="font-size: 0.8em;"><sup>ABc</sup></span>&frasl;<span style="font-size: 0.6em;">abC</span>
+<span style="font-size: 0.8em;"><sup>Abc</sup></span>&frasl;<span style="font-size: 0.6em;">aBC</span>
+<span style="font-size: 0.8em;"><sup>AbC</sup></span>&frasl;<span style="font-size: 0.6em;">aBc</span>. This would yield the following
+eight kinds of gametes, <i>ABC</i>, <i>abc</i>, <i>ABc</i>, <i>abC</i>, <i>Abc</i>, <i>aBC</i>, <i>AbC</i>,
+<i>aBc</i>, each bearing one of each kind of chromosome required to cover the
+entire field of characters necessary to a complete organism. And since
+each sex would be equally likely to have these eight types of gametes and
+any one of the eight in one individual might meet any one of the eight of
+the other, the possible number of combinations in the production of a new
+individual from such germ-cells would be 8x8, or 64. With the larger
+numbers of chromosomes which exist in most animals it is readily seen that
+the number of possible combinations becomes very great. Thus any
+individual of a species with twenty chromosomes&mdash;and many animals,
+including man, have more&mdash;would have ten pairs at the reduction period and
+could therefore form (2)<sup>10</sup>, or 1,024 different gametes in each sex. And
+since any one of these in one sex would have an equal chance of meeting
+with any one in the opposite sex, the total number of possible different
+zygotes that might be produced would be (1,024)<sup>2</sup>, or 1,048,576. Sex
+therefore, through recombinations of ancestral materials, undoubtedly
+means, among other things, the production of great diversity in
+offspring.</p>
+
+
+<p>&nbsp;<span class="pagenum"><a name="Page_55" id="Page_55">[Pg 55]</a></span></p>
+<p class="center">DETERMINATION OF SEX</p>
+
+<p><b>Many Theories.&mdash;</b>From earliest times the problem of sex determination has
+been one of keen interest, and needless to say hundreds of theories have
+been propounded to explain it. Geddes and Thomson say that Drelincourt
+recorded two hundred sixty-two so-called theories of sex production and
+remark that since his time the number has at least been doubled. The
+desirability of controlling sex has naturally appealed strongly to
+breeders of domesticated animals.</p>
+
+<p>A study of animals born in litters, or of twins, is enough in itself to
+make us skeptical of theories of sex-determination based on nutritional or
+external factors. In a litter of puppies, for example, there are usually
+both males and females, although in their prenatal existence they have all
+been subject to the same nutritional and environmental conditions.
+Likewise in ordinary human twins one may be a boy, the other a girl,
+whereas if the nutritional condition of the mother were the fact
+determining sex, both should be boys or both girls. However, there are
+twins known as <i>identical twins</i> who are remarkably alike and who are
+always of the same sex. But there is reason to suppose that identical
+twins in reality come from the same zygote. Presumably in early
+embryogeny, probably at the two-celled stage of cleavage, the two
+blastomeres become separated and each gives rise to a complete individual
+instead of only the half of one it would have produced had the two
+blastomeres remained together. Such twins are monochorial; that is, they
+grow inside the same fetal membrane, whereas each ordinary twin has<span class="pagenum"><a name="Page_56" id="Page_56">[Pg 56]</a></span> its
+own fetal membrane and has obviously originated from a separate ovum. It
+has been established experimentally in several kinds of animals that early
+cleavage blastomeres when isolated can each develop into a complete
+individual. In man, ordinary twins are no more alike than ordinary
+brothers and sisters, but identical twins are strikingly similar in
+structure, appearance, habits, tastes, and even susceptibility to various
+maladies. The fact that they are invariably of the same sex is a strong
+reason for believing that sex was already developed in the fertile ovum
+and consequently in the resulting blastomeres from that ovum.</p>
+
+<p>The young of the nine-banded armadillo in a given litter are invariably of
+the same sex and are closely similar in all features. Newman and Patterson
+have shown that all the members of a litter come from the same egg.
+Patterson has established the fact that cleavage of the egg takes place in
+the usual manner, but later separate centers of development appear in the
+early embryonic mass and give rise to the separate young individuals.</p>
+
+<p>Again in certain insects where one egg indirectly gives rise to a chain of
+embryos, or to a number of separate larv&aelig;, possibly as many as a thousand,
+all of the latter are of the same sex. Even in some plants researches have
+shown that sex is already determined at the beginning of development.
+Then, too, much evidence has come to light recently showing that
+sex-characters in certain cases behave as heritable characters and are
+independent of external conditions. Lastly there is visible and convincing
+evidence obtainable through microscopical observations that sex is
+determined<span class="pagenum"><a name="Page_57" id="Page_57">[Pg 57]</a></span> by a mechanism in the germ-cells themselves. It is chiefly to
+these latter facts that I wish to direct attention for the present.</p>
+
+<p><b>The Sex Chromosome.&mdash;</b>The evidence centers about a special chromosome or
+chromosome-group commonly designated as the <i>sex-chromosome</i> or
+<i>X-element</i>, which has been found in various species of animals, including
+man. In the males of such animals this chromosome is present in addition
+to the regular number of pairs, thus giving rise to an <i>uneven</i> instead of
+the conventional even number of chromosomes. This element remains
+undivided in one of the maturation divisions of the spermatocytes, in some
+forms in the first in others in the second, and passes entire to one pole
+of the spindle (Fig. 13, <a href="#Page_58">p. 58</a>). This results in the production of two
+classes of cells, one containing the <i>X</i>-element and one not. The outcome
+is that two corresponding classes of spermatozoa are produced. The
+phenomena involved are diagrammatically represented in Fig. 13. It has
+been clearly demonstrated in several cases that eggs fertilized by
+spermatozoa which possess this <i>X</i>-element, always become females, those
+fertilized by spermatozoa which do not possess it always develop into
+males.</p>
+
+<p>&nbsp;<span class="pagenum"><a name="Page_58" id="Page_58">[Pg 58]</a></span></p>
+<div class="figcenter"><img src="images/img13.jpg" alt="" /></div>
+<p class="center"><span class="smcap">Fig. 13</span></p>
+
+<p class="descrip">Diagram illustrating the behavior of the <i>x</i>-element or sex-chromosome in
+the maturation of the sperm-cell. In one of the two maturation divisions
+(represented here as in the first) it passes undivided to one pole
+(<i>a</i>, <i>b</i>, <i>c</i>), in the other it divides. Since the cell without the
+<i>x</i>-element also divides the result is that ultimately from the original
+primary spermatocyte (<i>a</i>) four cells are formed (<i>f</i>), two with the
+<i>x</i>-element and two without it. Half of the spermatozoa therefore will
+bear an <i>x</i>-element, half will be without it. In <i>a</i> the ordinary
+chromosomes, arbitrarily indicated as 10, are supposed to have already
+paired for reduction so that the original diploid number in spermatogonia
+and body-cells of the male would be 20 plus the <i>x</i>-chromosome.</p>
+<p>&nbsp;</p>
+
+<p>It has been found, furthermore, that in species in which the males possess
+this extra element the females have two of them. That is, if the original
+number in the somatic cells of the male were twenty-three, twenty-two
+ordinary and one <i>X</i>-element, the number in the somatic cells of the
+female would be twenty-four, or twenty-two ordinary and two <i>X</i>-elements.
+It has been found that when the chromosomes of the female pair for the
+reduction division, each chromosome uniting with its corresponding fellow,
+the two <i>X</i>-elements in the female pair in the usual way so that every
+egg-cell possesses an <i>X</i>-element. Thus every <span class="pagenum"><a name="Page_59" id="Page_59">[Pg 59]</a></span>mature egg has an
+<i>X</i>-element, while only half of the spermatozoa have one. That is, if we
+assume twenty-three as the diploid number present originally in the
+somatic cells of the male and twenty-four as the number in the female,
+then one-half the spermatozoa of the male would contain the haploid number
+eleven, and the other half, the number twelve, whereas every mature ovum
+would contain twelve. Since there are equal numbers of the spermatozoa
+with the <i>X</i>-element and without it, and inasmuch as presumably under
+ordinary conditions one kind is as likely to fertilize the egg as the
+other, then there are equal chances at fertilization of producing a zygote
+with two <i>X</i>-elements or with but one.</p>
+
+<table border="0" cellpadding="0" cellspacing="5" summary="table">
+<tr><td>Thus,</td><td>Spermatozoon + <i>X</i> by Ovum + <i>X</i> = Zygote + <i>XX</i>.</td></tr>
+<tr><td>&nbsp;</td><td>Spermatozoon (no <i>X</i>) by Ovum + <i>X</i> = Zygote + <i>X</i>.</td></tr></table>
+
+<p>We have already seen that the former is always female, the latter male. It
+thus becomes possible to distinguish the sex of an embryo by counting the
+chromosomes of its cells. This has been accomplished in several cases.</p>
+
+<p>In some instances<a name='fna_1' id='fna_1' href='#f_1'><small>[1]</small></a> the conditions may be much<span class="pagenum"><a name="Page_60" id="Page_60">[Pg 60]</a></span> more complex than the
+ones indicated&mdash;too complex in fact to warrant detailed discussion in an
+elementary exposition&mdash;but the principle remains the same throughout, the
+very complexity when thoroughly understood, strengthening rather than
+weakening the evidence. In a few forms an interesting reversal of
+conditions has been found in that the eggs instead of the spermatozoa show
+the characteristic dimorphism.</p>
+
+<p>Just what the exact relationship between sex-differentiation and the
+<i>X</i>-element is has never been clearly established. It is possible that
+this element is an actual sex-determinant, in the ordinary cases one
+<i>X</i>-element determining the male condition and two <i>X</i>-elements producing
+the female condition. On the other hand it might be argued that it is not
+the determining factor but the expression of other cell activities which
+do determine sex; that is, a sex accompaniment. Or again, it may be one of
+several essential factors which must cooperate to determine sex.</p>
+
+
+<p>&nbsp;</p>
+<p class="center">SEX-LINKED CHARACTERS</p>
+
+<p>The discovery of the remarkable behavior of certain characters in heredity
+which can only be plausibly explained by supposing that they are linked
+with a sex-determining factor still further strengthens our belief in the
+existence of such a definite factor. Such characters are commonly termed
+sex-linked characters.</p>
+
+<p><b>Sex-Linked Characters in Man.&mdash;</b>Since there are a number of them in man we
+may choose one of these, such as color-blindness, for illustration. The
+common form of color-blindness known as Daltonism<span class="pagenum"><a name="Page_61" id="Page_61">[Pg 61]</a></span> in which the subject
+can not distinguish reds from greens, a condition which seems to be due to
+the absence of something which is present in individuals of normal color
+vision, is far commoner in men than in women. Its type of inheritance,
+sometimes termed &#8220;crisscross&#8221; heredity, has been likened to the knight
+moves in a game of chess. The condition is transmitted from a color-blind
+man through his daughter to half of her sons. Or, to go more into detail,
+a color-blind father and normal mother have only normal children whether
+sons or daughters. The sons continue to have normal children but the
+daughters, although of normal vision themselves, transmit color-blindness
+to one-half of their own sons. If such a woman marries a color-blind man,
+as might easily happen in a marriage between cousins, then as a rule
+one-half her daughters as well as one-half her sons will be color-blind.</p>
+
+<p>&nbsp;<span class="pagenum"><a name="Page_62" id="Page_62">[Pg 62]</a></span></p>
+<div class="figcenter"><img src="images/img14.jpg" alt="" /></div>
+<p class="center"><span class="smcap">Fig. 14</span></p>
+
+<p class="descrip">Diagram illustrating the inheritance of a sex-limited character such as
+color-blindness in man on the assumption that the factor in question is
+located in the sex-chromosome (from Loeb after Wilson). The normal
+sex-chromosome is indicated by a black <b>X</b>, the one lacking the factor for
+color perception, by a light X. It is assumed that a normal female is
+mated with a color-blind male.</p>
+<p>&nbsp;</p>
+
+<p>In such cases what appears to be a mysterious procedure becomes very
+simple if we assume that the defective character is associated with the
+sex-determining factor, or to make it concrete let us say with the
+<i>X</i>-element. The chart shown in Fig. 14, <a href="#Page_62">p. 62</a>, indicates what the
+germinal condition would be under the circumstances. The column to the
+right represents the maternal, the one to the left the paternal line.
+Since two <i>X</i> means female and one <i>X</i> male, and inasmuch as we have
+assumed that the physical basis of the defect to which color-blindness is
+due is conveyed by the <i>X</i>-element, we may represent the defective single
+<i>X</i> of the male in outline only (see first row). It is obvious that after
+the reduction divisions (second row) the <span class="pagenum"><a name="Page_63" id="Page_63">[Pg 63]</a></span>mature sex-cells of the female
+will each contain a single normal <i>X</i>, the corresponding sex cells of the
+male will contain either no <i>X</i> or a defective <i>X</i>. Since if any member of
+the class of spermatozoa containing no <i>X</i>, fertilizes an egg the
+resulting zygote (row three) will have but one <i>X</i> and that a normal one,
+the individual which develops from the zygote will be normal as regards
+color vision and moreover will be male because the condition one <i>X</i>
+always means maleness. On the other hand, if any member of the class of
+spermatozoa containing the defective <i>X</i> fertilizes an egg two
+<i>X</i>-elements are brought together and this of itself means femaleness. In
+this case one of the <i>X</i>-elements is defective but the single normal <i>X</i>
+is sufficient in itself to produce normal color vision. But when it comes
+to the maturation of the sex-cells of this female, the pair of
+<i>X</i>-elements are separated in the usual way with the result that half of
+the mature ova contain a normal <i>X</i> and half a defective <i>X</i> (row four).
+Since in a normal male, however, the mature reproductive cells will
+contain either a normal <i>X</i> or no <i>X</i> (fourth row), any one of four
+different kinds of matings may result. A sex-cell carrying normal <i>X</i> of
+the male may combine with an ovum containing normal X producing a normal
+female (row five). Or such a cell may combine with an ovum carrying the
+defective <i>X</i>, also producing a female but one who although of normal
+color vision herself, like her mother, is a carrier of the defect. On the
+other hand, any one of the spermatozoa without an <i>X</i> may combine with an
+ovum containing the normal <i>X</i>, in which case a normal male is produced
+and, moreover, one who, like his mother&#8217;s brothers,<span class="pagenum"><a name="Page_64" id="Page_64">[Pg 64]</a></span> is incapable of
+transmitting the defect. However, the sperm-cell devoid of an <i>X</i> is just
+as likely to fertilize an ovum carrying the defective <i>X</i>, in which event
+the resulting individual, a male, must be color-blind because he contains
+the defective <i>X</i> alone. In other words, the chances are that one-half the
+sons of a woman whose father was color-blind will be color-blind, the
+other half perfectly normal; and that all of the daughters will be of
+normal color vision although one-half of them will probably transmit the
+defect to one-half of their sons. From a glance at the diagram it is
+readily seen also that a color-blind female could result from the union of
+a color-blind man (see first row) and the daughter of a color-blind man
+(see third row). For half of the gametes of such a female would bear the
+defect as would also that half of the gametes of the male which carry <i>X</i>,
+hence the expectation would be that half of the daughters of such a union
+would be color-blind and half would be carriers of color-blindness; and
+that half of the sons would be color-blind and half normal. All the sons
+of a color-blind woman would be color-blind because she has only defective
+<i>X</i>-elements to pass on.</p>
+
+<p>The inheritance of various other conditions in man follows more or less
+accurately the same course as color-blindness. Among these may be
+mentioned: <i>hemophilia</i>, a serious condition in which the blood will not
+clot properly, thus rendering the affected individual constantly liable to
+severe or fatal hemorrhage; near-sightedness (<i>myopia</i>) in some cases; a
+degenerative disease of the spinal cord known as <i>multiple sclerosis</i>;
+progressive atrophy of the optic nerve <span class="pagenum"><a name="Page_65" id="Page_65">[Pg 65]</a></span>(<i>neuritis optica</i>); Gower&#8217;s
+<i>muscular atrophy</i>; some forms of <i>night-blindness</i>; in some cases
+<i>ichthyosis</i>, a peculiar scaly condition of the skin. In one of my own
+tabulations of a case of inheritance of &#8220;webbed&#8221; digits or <i>syndactyly</i>, a
+condition in which two or more fingers or toes are more or less united, a
+sex-linked inheritance is clearly indicated (Fig. 15), although from the
+pedigrees recorded by other investigators this condition usually appears
+in some of both the sons and daughters of an affected individual.</p>
+
+<p>&nbsp;</p>
+<div class="figcenter"><img src="images/img15.jpg" alt="" /></div>
+<p class="center"><span class="smcap">Fig. 15</span></p>
+
+<p class="descrip">Chart showing the inheritance of a case of syndactyly after the manner of
+a sex-linked character. The affected individuals are represented in black;
+squares indicate males, circles females. The condition is seen to be
+inherited by males through unaffected females.</p>
+<p>&nbsp;</p>
+
+<p><b>The Occurrence of Sex-Linkage in Lower Forms Renders Experiments
+Possible.&mdash;</b>The course followed by such characters in man can be inferred
+only from the pedigrees we can obtain from family <span class="pagenum"><a name="Page_66" id="Page_66">[Pg 66]</a></span>histories. Fortunately,
+however, such sex-linkage also occurs in lower animals and we are able
+therefore to verify and extend our observations by direct experiments in
+breeding. Several sex-linked characters have been found to exist in a
+small fruit-fly known as <i>Drosophila</i>. Extensive breeding experiments with
+this fly by Professor T. H. Morgan and his pupils have borne out
+remarkably the interpretation that the characters in question are really
+linked with a sex-determining factor.</p>
+
+
+
+<p>&nbsp;</p><p>&nbsp;</p>
+<hr style="width: 50%;" />
+<p><span class="pagenum"><a name="Page_67" id="Page_67">[Pg 67]</a></span></p>
+<h2><a name="CHAPTER_III" id="CHAPTER_III"></a>CHAPTER III</h2>
+<p class="title">MENDELISM</p>
+
+
+<p><b>New Discoveries in the Field of Heredity.&mdash;</b>Writing in 1899, one of
+America&#8217;s well-known zoologists asserts that, &#8220;It is easier to weigh an
+invisible planet than to measure the force of heredity in a single grain
+of corn.&#8221; And yet only two or three years later we find another prominent
+naturalist saying regarding heredity that, &#8220;The experiments which led to
+this advance in knowledge are worthy to rank with those that laid the
+foundation of the atomic laws of chemistry.&#8221; Again, &#8220;The breeding pen is
+to us what the test-tube is to the chemist&mdash;an instrument whereby we
+examine the nature of our organisms and determine empirically their
+genetic properties.&#8221; Here is a decided contrast of statement and yet both
+were justifiable at the time of utterance. For even at the writing of the
+first statement the investigations were in progress which, together with
+the rediscovery of certain older work, were to transfer our knowledge of
+heredity from the realm of speculation to that of experiment and disclose
+certain definite principles of genetic transmission.</p>
+
+<p>Through a knowledge of these principles in fact, the shifting of certain
+characters is reducible to a series of definitely predictable proportions
+and the skilled breeder may proceed to the building up of new and<span class="pagenum"><a name="Page_68" id="Page_68">[Pg 68]</a></span>
+permanent combinations of desirable characters according to mathematical
+ratios and, what is of equal importance, he can secure the elimination of
+undesirable qualities. While there are many limitations in the application
+of these principles and while new facts and modifications are constantly
+being discovered concerning them, nevertheless they represent the first
+approximations to definite laws of hereditary transmission that we have
+ever been able to make, and the practical fact confronts us that whatever
+our theoretical interpretations may be, the principles are so definite
+that through their application important improvements of crops and
+domesticated animals have already actually been secured and one may
+confidently expect still others to follow.</p>
+
+<p><b>Mendel.&mdash;</b>The principles involved are called the Mendelian principles after
+their discoverer, Gregor Johann Mendel, abbot of a monastery at Br&uuml;nn,
+Austria. After eight years of patient experimenting in his cloister garden
+with plants, chiefly edible peas, he published his results and conclusions
+in 1866, in the <i>Proceedings of the Natural History Society of Br&uuml;nn</i>.
+While known to a few botanists of that day, the full importance of the
+contribution was not recognized, and in the excitement of the
+post-Darwinian controversy, the facts were lost sight of and ultimately
+forgotten.</p>
+
+<p><b>Rediscovery of Mendelian Principles.&mdash;</b>In 1900 three men, Correns, De Vries
+and Tschermak, working independently&mdash;in different countries, in
+fact&mdash;rediscovered the principles and called attention anew to the
+long-forgotten work of Mendel which they had come upon in looking over the
+older literature on plant<span class="pagenum"><a name="Page_69" id="Page_69">[Pg 69]</a></span> breeding. These investigators added other
+examples from their own experiments. Since their rediscovery the
+principles have been confirmed in essential features and extended by
+numerous experimentalists with regard to a wide range of hereditary
+characters in both animals and plants.</p>
+
+<p><b>Independence of Inheritable Characters.&mdash;</b>It has been found that many truly
+heritable characteristics or traits of an individual, whether plant or
+animal, are comparatively independent of one another and may be inherited
+independently. Where there are contrasted characters in father and mother,
+such as white plumage and black plumage in fowls, smooth coat and wrinkled
+coat in seed, horns and hornlessness in cattle, long fur and short fur in
+rabbits, beard and beardlessness in wheat, albino condition and normal
+condition, etc., there is obviously a bringing together of the determiners
+of the two traits in the resulting offspring. In the third generation,
+however, in the progeny of these offspring, the two distinct characters
+may be set apart again, thus showing that in the second generation while
+perhaps one only was visible, the factors which determine both were
+nevertheless present, and moreover, they were present in a separable
+condition.</p>
+
+<p><b>Illustration of Mendelism in the Andalusian Fowl.&mdash;</b>Let us take as a simple
+example the case of the Andalusian fowl. Although it is not a case
+established by Mendel it illustrates certain of the essential conditions
+underlying Mendelism in a more obvious way than the cases worked out by
+Mendel himself. The so-called blue Andalusian fowl results from a cross of
+a color variety of the fowl which is black with one which<span class="pagenum"><a name="Page_70" id="Page_70">[Pg 70]</a></span> is white with
+black-splashed feathers. The result is the same irrespective of which
+parent is black. When bred with their like, whether from the same parents
+or different parents, these blue fowls produce three kinds of progeny,
+approximately one-fourth of which are black like the one grandparent,
+one-fourth white like the other grandparent, and the remaining half, blue
+like the parents (Fig. 16). Moreover, the black fowls obtained in this way
+will, when interbred, produce only black offspring and the same is true of
+the white fowls. To all appearances as far as color is concerned they are
+of as pure type as the original grandparents. With the blue fowls,
+however, the case is different, for when bred together they will produce
+the same three<span class="pagenum"><a name="Page_71" id="Page_71">[Pg 71]</a></span> kinds of progeny that their parents produced and in the
+same proportions. Again the white and the black are true to type but the
+blue will always yield the three classes of offspring and this through
+generation after generation.</p>
+
+<p>&nbsp;</p>
+<div class="figcenter"><img src="images/img16.jpg" alt="" /></div>
+<p class="center"><span class="smcap">Fig. 16</span></p>
+
+<p class="center">Diagram showing the scheme of inheritance in the blue Andalusian fowl.</p>
+<p>&nbsp;</p>
+
+<p>These facts may be illustrated graphically as follows where the word
+&#8220;black&#8221; indicates the original black parent, &#8220;white&#8221; the original white
+(black splashed) parent and &#8220;blue&#8221; the hybrid offspring.</p>
+
+<p>&nbsp;</p>
+<div class="figcenter"><img src="images/page71.jpg" alt="" /></div>
+<p>&nbsp;</p>
+
+<p><b>The Cause of the Mendelian Ratio.&mdash;</b>Concerning the cause of this peculiar
+ratio of inheritance in crossed forms Mendel suggested a simple
+explanation. Animals or plants that can be cross-bred, obviously must be
+forms that produce a new individual from the union of two germ-cells, one
+of which is provided by each parent. Mendel&#8217;s idea was that there must be
+some process of segregation going on in the developing germ-cells of each
+hybrid whereby the factors for the two qualities are set apart in
+different<span class="pagenum"><a name="Page_72" id="Page_72">[Pg 72]</a></span> cells with the result that half of the germ-cells of a given
+individual will contain the determiner of one character and half, the
+determiner of the other. That is, a given germ-cell carries a factor for
+one or the other of the two alternate characters but not the factors for
+both. In a plant, for example, in the male line, half of the pollen grains
+would bear germ-cells carrying the determiner of one character and half,
+that of the other. Similarly, in the female line, half of the ovules would
+contain the determiner of the one character and half, that of the other.
+Likewise in animals as regards such pairs of characters there would be two
+classes of germ-cells in the male and two in the female. In the case of
+the blue Andalusian fowls under discussion this would mean that half of
+the mature germ-cells of the male carry the black-producing factor, and
+half carry the white-producing factor, and the same is true of the
+germ-cells of the female. Thus when two such crossed forms are mated,
+there are, by the laws of chance, four possible combinations, namely: (1)
+white-determining sperm-cells and white-determining ovum; (2)
+white-determining sperm-cells and black-determining ovum; (3)
+black-determining sperm-cells and white-determining ovum; and (4)
+black-determining sperm-cells and black-determining ovum. Manifestly, the
+first combination can only give white offspring; the second, white and
+black, gives blue (by such a cross the original blues were established);
+likewise, the third, black and white, gives blue; and the fourth
+combination can only give black offspring. This matter may be graphically
+represented by the following formul&aelig; in which B indicates the<span class="pagenum"><a name="Page_73" id="Page_73">[Pg 73]</a></span> determiner
+of Black in the germ-cell and W the determiner of White: &#9794; signifies
+male; &#9792; female.</p>
+
+<p class="center">IN THE ORIGINAL PARENTS</p>
+
+<p class="center">W &times; B = WB = Blue</p>
+
+<p class="center">IN THE HYBRIDS</p>
+
+<table border="0" cellpadding="0" cellspacing="0" summary="table">
+<tr><td align="center">&#9794; germ-<br />cells</td>
+    <td align="center">&#9792; germ-<br />cells</td>
+    <td>&nbsp;</td><td>&nbsp;</td><td>&nbsp;</td>
+    <td align="center">&#9794;</td>
+    <td>&nbsp;</td>
+    <td align="center">&#9792;</td></tr>
+<tr><td colspan="2" rowspan="4" align="center"><img src="images/page73.jpg" alt="" /></td>
+    <td><span class="spacer">&nbsp;</span></td>
+    <td>&nbsp;</td>
+    <td><span class="spacer">&nbsp;</span></td>
+    <td>W</td>
+    <td align="center">&times;</td>
+    <td>W</td>
+    <td>==</td>
+    <td>WW</td>
+    <td>==</td>
+    <td>White</td></tr>
+<tr><td>&nbsp;</td>
+    <td rowspan="2" align="center">or</td>
+    <td>&nbsp;</td>
+    <td>W</td>
+    <td align="center">&times;</td>
+    <td>B</td>
+    <td>==</td>
+    <td>WB</td>
+    <td>==</td>
+    <td>Blue</td></tr>
+<tr><td>&nbsp;</td><td>&nbsp;</td><td>B</td>
+    <td align="center">&times;</td>
+    <td>W</td>
+    <td>==</td>
+    <td>BW</td>
+    <td>==</td>
+    <td>Blue</td></tr>
+<tr><td>&nbsp;</td><td>&nbsp;</td><td>&nbsp;</td>
+    <td>B</td>
+    <td align="center">&times;</td>
+    <td>B</td>
+    <td>==</td>
+    <td>BB</td>
+    <td>==</td>
+    <td>Black</td></tr></table>
+
+<p>Thus of the four possible combinations one only can produce white fowls,
+two (WB or BW) can produce blue fowls, and one black fowls. That is, the
+ratio is 1:2:1 or the 25, 50 and 25 per cent., respectively, of our
+diagram. The black fowls or the white fowls will breed true in subsequent
+generations when mated with those of their own color because the
+determiner of the alternative character has been permanently eliminated
+from their germ-plasm; but the blue fowls will always yield three types of
+offspring because they still possess the two classes of germ-cells.</p>
+
+<p><b>Verification of the Hypothesis.&mdash;</b>The hypothesis that germ-cells of crossed
+forms are of two classes with respect to a given pair of Mendelian
+characters is further substantiated by the following facts. If in the case
+of the fowls under discussion one of the blue fowls is mated with an
+individual of the white variety,<span class="pagenum"><a name="Page_74" id="Page_74">[Pg 74]</a></span> half of the progeny will be blue and
+half white. For the hybrid has two kinds of germ-cells, black producing,
+which we have designated by the letter B, and white producing (or W) in
+equal number while the white parent has only one kind, white producing. It
+is obvious that if half the germ-cells of the hybrid form are of the type
+B then half the progeny will be of the BW type, which is blue, and the
+other half will be of the WW type, which is white. In the same way if we
+mate a hybrid and a black fowl, half of the progeny will be black and half
+will be blue, that is, there could only be WB and BB types.</p>
+
+<p>The fact must not be lost sight of that since the pairings are wholly
+determined by the laws of chance the proportions are likely to be only
+approximate. It is obvious that the greater the number of individuals, the
+nearer the results will approach the expected ratio.</p>
+
+
+<p>&nbsp;</p>
+<p class="center">DOMINANT AND RECESSIVE</p>
+
+<p><b>One Character May Mask the Other.&mdash;</b>In a large number of cases, however,
+the actual condition of affairs is not so evident as in the Andalusian
+fowl, for instead of being intermediate or different in appearance, the
+generation produced by crossing resembles one parent to the exclusion of
+the other. Such an overshadowing is spoken of as <i>dominance</i>, and the two
+characters are termed <i>dominant</i> and <i>recessive</i>. Thus when brown
+ring-doves and white ring-doves are mated the progeny are all brown, or if
+wild gray mice are mated to white mice the progeny are all gray. So black
+is dominant to white in rose-comb bantams; brown eyes to blue eyes in man;
+beardlessness<span class="pagenum"><a name="Page_75" id="Page_75">[Pg 75]</a></span> to beard in wheat, and likewise rough chaff to smooth, and
+thick stem to thin; tallness to dwarfness in various plants; normal
+condition to the peculiar waltzing condition in the Japanese waltzing
+mouse. Numerous other cases might be cited but these are sufficient to
+illustrate the condition.</p>
+
+<p><b>Segregation in the Next Generation.&mdash;</b>But now the question arises, what do
+such crosses as show dominance transmit to the next generation?
+Experiments show regarding any given pair of these alternate characters
+that they are set apart again in the succeeding generation, returning in a
+definite percentage to the respective grandparental types.</p>
+
+<p>&nbsp;</p>
+<div class="figcenter"><img src="images/img17.jpg" alt="" /></div>
+<p class="center"><span class="smcap">Fig. 17</span></p>
+
+<p class="descrip">Diagram showing the scheme of inheritance in guinea-pigs when black and albino forms are crossed.</p>
+<p>&nbsp;</p>
+
+<p><b>Dominance Illustrated in Guinea-Pigs.&mdash;</b>In guinea-pigs for example (Fig.
+17), when an individual (either male or female) of a black variety, is
+<span class="pagenum"><a name="Page_76" id="Page_76">[Pg 76]</a></span>crossed with one of a white variety, the F<sub>1</sub> generation are all black
+like the black parent. When these are interbred or bred with other blacks
+which have had one black and one white parent, only two visible types of
+progeny appear, viz., black and white, and these approximately in the
+ratio of three to one.</p>
+
+<p>Analysis by further breeding shows, however, that there are in reality
+three types, but since dominance is complete the pure extracted dominant
+and the mixed dominant-and-recessive type are indistinguishable to our
+eye. That is, while the blacks are three times as numerous as the whites,
+two out of every three of these blacks are really hybrid and correspond to
+the blue fowls of our former example.</p>
+
+<p>The condition is readily comprehended when expressed diagrammatically
+thus:</p>
+
+<p>&nbsp;</p>
+<div class="figcenter"><img src="images/page76.jpg" alt="" /></div>
+<p>&nbsp;</p>
+
+<p>In other words, the germ-cells of the one original parent (Gen. P) would
+contain only determiners for black and that of the other parent would
+contain only determiners for white. The condition of the individuals
+produced by the cross would be represented by the formula B(W). But these
+determiners segregate in the germ-cells of the crossed form, whether it be
+male or female, into B and W. Hence half the spermatozoa of the male
+hybrid (generation F<sub>1</sub>) would carry the B determiners and half the W
+determiners.<span class="pagenum"><a name="Page_77" id="Page_77">[Pg 77]</a></span> The same is true of the mature ova of the female hybrid.
+Consequently, in mating there are always four equally possible
+combinations, viz., BB, B(W), (W)B, and WW. Since B is always dominant
+three out of the four matings would yield black individuals, or in other
+words the ratio would be 3:1.</p>
+
+<p>The pure blacks when mated together will breed true in subsequent
+generations, likewise the whites, but the blacks carrying white as a
+recessive will yield when interbred the same ratio of whites and black as
+did their hybrid parents (Fig. 17, <a href="#Page_75">p. 75</a>).</p>
+
+<p><b>Terminology.&mdash;</b>As work in the study of Mendelian inheritance has progressed
+and expanded the need of a more precise terminology has become evident and
+such is gradually being established. Thus Professor Bateson has coined the
+term &#8220;allelomorph&#8221; (Gk. <i>one another</i>, and <i>form</i>) to express more exactly
+what we have thus far been calling a pair of alternate or opposite
+characters. In the blue Andalusian fowls discussed, the white condition in
+the one parent is the allelomorph of the black condition in the other. The
+term generally means one of the pair of Mendelian characters themselves as
+expressed in the individual plants or animals but when the germinal basis
+of such phenomena is under discussion, it is sometimes used to refer to
+the determiners of such characters. And by determiner is meant simply the
+condition which is necessary in the germ to bring about the occurrence of
+a definite character. For example, when we are studying a cross between a
+red flower and a white flower with reference to the color factors, the
+difference between the two plants may lie in the fact that<span class="pagenum"><a name="Page_78" id="Page_78">[Pg 78]</a></span> one produces a
+red coloring matter and the other does not. That is, the determiner for
+red is absent from the white variety. What the exact relation of color
+production is to the parts of the germ-cell we do not know. It could be
+the function of a single definite body or the resultant of several
+cooperating bodies. The latter is far more likely to be the case. We may
+suppose that a group of cooperating substances function to produce red in
+the red flower but that in the white flowers one of these bodies is absent
+or fails to perform its red-producing function.</p>
+
+<p>It is customary where practicable to refer to the determiner of a
+character by the initial letter of the name of the character. The letter
+when written as a capital indicates the determiner but when written as a
+small letter the absence of the determiner. Thus R may be taken to
+represent the determiner for red coloring matter and r its absence. It is
+convenient also to have a brief symbol to denote a given generation and
+for this purpose Bateson has introduced the symbol F<sub>1</sub> for the hybrid
+progeny of the first cross, the initial letter of the word &#8220;filial.&#8221; F<sub>2</sub>
+would indicate the next generation, F<sub>3</sub> the third and so on. Likewise P
+denotes the original parent generation.</p>
+
+<p><b>The Theory of Presence and Absence.&mdash;</b>Many, if not all, allelomorphs
+consist of the presence and absence respectively of a given determiner. In
+such cases the character represented by the presence of the determiner is
+dominant over the character represented by the absence of a determiner.
+Thus in the crosses from the wild gray mice and albino mice the progeny
+are all gray mice since one parent had the determiner or<span class="pagenum"><a name="Page_79" id="Page_79">[Pg 79]</a></span> group of
+determiners for grayness and the hybrid offspring must also possess it.
+Likewise the presence of black in black guinea-pigs is dominant to its
+absence in albino guinea-pigs and the resulting progeny are all black.</p>
+
+<p>However, it has already been mentioned that beardlessness in wheat is
+dominant to beard and that the absence of horns in cattle is dominant to
+their presence, that is, the progeny of hornless by horned cattle are
+without horns except for occasional traces of imperfect horns. Facts like
+these would seem at first sight to contradict the assertion just made that
+presence is dominant to absence, but it is fairly well established that in
+such cases one is not dealing with true absences but with suppressions.
+The polled breeds of cattle, for example, are hornless not because of the
+absence of determiners for horns but because of the presence of an
+additional inhibiting factor which prevents these determiners from
+functioning. The horned breeds are without this inhibitor. When horned and
+hornless individuals are crossed the presence of the inhibitor from one
+line of ancestry is sufficient to suppress the development of horns in the
+progeny. A similar explanation would, of course, apply to beardlessness in
+wheat.</p>
+
+<p>In writing double-lettered formul&aelig; to denote the determiners of characters
+in hybrids the condition is represented merely by the capital and small
+letter. Thus Rr indicates that red is dominant to its absence.</p>
+
+<p><b>Additional Terminology.&mdash;</b>In pure breeds where the determiners are alike as
+BB in black or bb in albino guinea-pigs, the individual is said to be a
+<span class="pagenum"><a name="Page_80" id="Page_80">[Pg 80]</a></span><i>homozygote</i> (like things united) with reference to that character, while
+in those in which the determiners are unlike, as Bb, the individual is
+termed a <i>heterozygote</i> (unlike things united) with reference to the
+character. Or to use the adjective forms, a pure black guinea-pig is
+homozygous for black pigment, an albino guinea-pig is homozygous for
+absence of pigment, while a cross between the two is heterozygous for
+pigment. Also, where the determiner of a given character is present in
+double quantity, that is, from both lines of ancestry, the individual is
+said to be <i>duplex</i>, where represented in only the single form as in
+heterozygous individuals, <i>simplex</i>, and where the determiner is absent
+entirely, <i>nulliplex</i>, with reference to the character in question. Thus
+black guinea-pigs of formula BB are duplex with regard to the determiner
+for black color, individuals of formula Bb are simplex with reference to
+this determiner, and those of formula bb are nulliplex.</p>
+
+<p>A heterozygote in which dominance prevails can be identified with
+certainty by breeding to a known recessive and noting the kind of
+offspring produced. If the individual was really a heterozygote,
+approximately fifty per cent. of the offspring should be of the recessive
+type.</p>
+
+<p><b>Dominance Not Always Complete.&mdash;</b>As a matter of fact close inspection shows
+that in numerous instances dominance is not absolute since traces of the
+recessive character may be detectable. For example, in the cross between
+smooth and bearded wheat while smoothness is regarded as the dominant
+character and beardlessness as the recessive, nevertheless in the hybrid<span class="pagenum"><a name="Page_81" id="Page_81">[Pg 81]</a></span>
+offspring a slight tendency toward bearding is not infrequently seen. Or
+again when horned breeds of cattle are crossed with hornless ones, a small
+proportion of such progeny will show traces of imperfect horns.</p>
+
+<p>In some cases instead of either character dominating the other a form
+intermediate between the two parents may result, as we have seen already
+in the case of the Andalusian fowl. Thus, certain white-flowered plants
+and certain red-flowered plants when crossed produce pink hybrids, and
+longheaded and shortheaded wheats when crossed give offspring with heads
+of intermediate length. Or again, crosses between white and red cattle may
+yield red roans, and between black and white cattle, blue roans.</p>
+
+<p>Thus, while for such pairs of alternative characters as have been studied,
+dominance to some considerable degrees at least, seems to be the rule,
+still we have gradations down to the intermediate condition, and in some
+instances the hybrid with respect to a given character may be unlike
+either parent. The things of chief importance in the Mendelian discovery
+are the independent, unitary nature of the characters and their
+segregation in the offspring of cross-bred forms.</p>
+
+<p><b>Modifications of Dominance.&mdash;</b>It should be noted also that there is such a
+condition as <i>delayed dominance</i>. Davenport found, for example, that
+chicks produced by crossing pure white with pure black Leghorn fowls are
+speckled black and white, but later in the adult form white becomes
+dominant. Likewise conditions of delayed dominance are known in man in
+eye-color and notably in color of hair. Some few cases have been recorded
+where a character is dominant at<span class="pagenum"><a name="Page_82" id="Page_82">[Pg 82]</a></span> one time, recessive at another.
+According to Davenport extra toe in fowls may behave in this way.</p>
+
+<p><b>Mendel&#8217;s Own Work.&mdash;</b>Mendel<a name='fna_2' id='fna_2' href='#f_2'><small>[2]</small></a> himself worked out his principles on seven
+pairs of characters which he found in common culinary peas. Placing the
+dominant characters first, these may be enumerated as follows: (1) Tall by
+dwarf; (2) green pod (unripe) by yellow; (3) pod inflated by pod
+constricted between the individual peas; (4) flowers arranged along the
+axis of the plant by flowers bunched together at the top; (5) seed skin
+colored by seed skin white; (6) cotyledons yellow by cotyledons green; (7)
+seed rounded by seed wrinkled.</p>
+
+<p>He found that each pair of characters followed the same law as any other
+pair when more than one pair of the characters occurred in the same
+plants, but that each pair behaved independently of the other. The meaning
+of this is that we may get various combinations of characters not
+associated in the original pure stocks, the number of such combinations
+depending on the number of pairs of allelomorphs there are.</p>
+
+
+<p>&nbsp;</p>
+<p class="center">DIHYBRIDS</p>
+
+<p><b>Getting New Combinations of Characters.&mdash;</b>Since this principle is well
+illustrated in peas, let us take two pairs of their characters, viz.,
+greenness and yellowness (of the cotyledons) and roundness and angularity
+to see exactly what happens when two pairs of <span class="pagenum"><a name="Page_83" id="Page_83">[Pg 83]</a></span>allelomorphs are involved.
+When a specific kind of yellow pea is crossed with a particular kind of
+green pea the offspring are always yellow (Fig. 18, opposite <a href="#Page_85">p. 84</a>). When
+these hybrids (generation F<sub>1</sub>) are self-fertilized there is the usual
+Mendelian segregation; one-fourth the resulting offspring will be green,
+one-fourth pure yellow, and one-half, although yellow in appearance, will
+be of the mixed type. The exact numbers found by Mendel were 6,022 yellow
+seeds to 2,001 green seeds. Now of the original peas (generation P) the
+yellow ones are round and the green ones angular (really wrinkled).
+Choosing this roundness and angularity respectively as a pair of
+characters they are found to follow the same law that the colors follow
+(Mendel obtained in the F<sub>2</sub> generation 5,474 round and 1,850 wrinkled
+seed), but independently of the latter. For while in the progeny of the
+hybrids (Gen. F<sub>1</sub>), twenty-five per cent. will be round and of pure type
+as regards roundness, twenty-five per cent. angular, and fifty per cent.
+round but containing hidden factors of angularity (i. e., roundness is
+dominant), the roundness and the yellowness, or the angularity and the
+greenness will not always go together as they did in the original
+grandparental strains, but there will be in addition some new types of
+round green peas and some of angular yellow ones. That is, the factors of
+color and of shape have been inherited independently of one another, so
+that instead of the two original kinds of peas, four have been produced,
+viz., (1) round-yellow (one of the original types); (2) round-green (new
+type); (3) angular-yellow (new type); and (4) <span class="pagenum"><a name="Page_84" id="Page_84">[Pg 84]</a></span>angular-green (one of the
+original types). Furthermore, these will be found to stand in the ratio of
+9:3:3:1 respectively.</p>
+
+<p><b>Segregations of the Determiners.&mdash;</b>How these combinations come about in
+this definite proportion is easily understood if the matter is expressed
+in terms of determiners and the possible matings tabulated (Fig. 18). If
+we represent the yellow determiner by Y and the green determiner by y, and
+likewise the determiners of roundness and angularity by R and r
+respectively, then the formul&aelig; for the determiners of these two pairs of
+characters in the body cells (that is, in the unreduced condition) of the
+pure forms and of the F<sub>1</sub> generation hybrids respectively are as
+follows:</p>
+
+<table border="0" cellpadding="0" cellspacing="0" summary="table">
+<tr><td>In pure round yellow peas</td>
+    <td><span class="spacer">&nbsp;</span></td>
+    <td align="right">RR</td>
+    <td>&nbsp;</td>
+    <td align="right">YY</td></tr>
+<tr><td>In pure angular green peas</td>
+    <td>&nbsp;</td>
+    <td align="right">rr</td>
+    <td>&nbsp;</td>
+    <td align="right">yy</td></tr>
+<tr><td>In the hybrid</td>
+    <td>&nbsp;</td>
+    <td align="right">Rr</td>
+    <td>&nbsp;</td>
+    <td align="right">Yy</td></tr></table>
+
+<p>But now in the segregation of these determiners in the germ-cells of the
+hybrids (generation F<sub>1</sub>) the pair of determiners Rr and the pair Yy
+operate entirely independently of one another. Their only compulsion is
+that each pair be separated into the single determiners, R and r in the
+one case and Y and y in the other. So in the separating division which
+brings about this divorcement R separates from r irrespective of whether
+it is accompanying Y or y into the resulting daughter cell. Thus in some
+cases R and Y would pass into one germ-cell, in others R and y, in others
+r <span class="pagenum"><a name="Page_85" id="Page_85">[Pg 85]</a></span>and Y, and in still others r and y, depending entirely upon the
+chance relations of the respective pairs to the plane of division. That
+is, the segregation is equally likely to be RY/ry giving gametes RY and
+ry, or Ry/rY giving gametes Ry and rY.</p>
+
+
+<p>&nbsp;</p>
+<div class="figcenter"><img src="images/img18.jpg" alt="" /></div>
+
+<table border="0" cellpadding="0" cellspacing="0" summary="table">
+<tr><td align="right"><small>&#9792;</small></td>
+    <td align="center">RY</td>
+    <td align="center">Ry</td>
+    <td align="center">rY</td>
+    <td align="center">ry</td></tr>
+<tr><td><small>&#9794;</small></td></tr>
+<tr><td class="br">RY</td>
+    <td class="btr">RRYY</td>
+    <td class="btr">RRYy</td>
+    <td class="btr">RRYY</td>
+    <td class="btr">RrYy</td></tr>
+<tr><td class="br">Ry</td>
+    <td class="btr">RRYy</td>
+    <td class="btr">RRyy</td>
+    <td class="btr">RrYy</td>
+    <td class="btr">Rryy</td></tr>
+<tr><td class="br">rY</td>
+    <td class="btr">RrYY</td>
+    <td class="btr">RrYy</td>
+    <td class="btr">rrYY</td>
+    <td class="btr">rrYy</td></tr>
+<tr><td class="br">ry</td>
+    <td class="btr">RrYy</td>
+    <td class="btr">Rryy</td>
+    <td class="btr">rrYy</td>
+    <td class="btr">rryy</td></tr>
+<tr><td>&nbsp;</td>
+    <td class="bt">&nbsp;</td>
+    <td class="bt">&nbsp;</td>
+    <td class="bt">&nbsp;</td>
+    <td class="bt">&nbsp;</td></tr></table>
+
+<table border="0" cellpadding="0" cellspacing="0" summary="table">
+<tr><td>(1) 1 RRYY</td>
+    <td><span class="spacer">&nbsp;</span></td>
+    <td>(4) 2 RrYY</td>
+    <td><span class="spacer">&nbsp;</span></td>
+    <td>(7) 1 rrYY</td></tr>
+<tr><td>(2) 2 RRYy</td>
+    <td>&nbsp;</td>
+    <td>(5) 4 RrYy</td>
+    <td>&nbsp;</td>
+    <td>(8) 2 rrYy</td></tr>
+<tr><td>(3) 1 RRyy</td>
+    <td>&nbsp;</td>
+    <td>(6) 2 Rryy</td>
+    <td>&nbsp;</td>
+    <td>(9) 1 rrYy</td></tr>
+<tr><td colspan="2">&nbsp;</td>
+    <td align="center">9:3:3:1</td></tr></table>
+
+<p class="center"><span class="smcap">Fig. 18</span></p>
+
+<p class="descrip">Diagram showing the possible combinations arising in the second filial
+generation (F<sub>2</sub>) following a cross between yellow, round (YYRR) and
+green, angular or wrinkled (yyrr) peas. Y, presence of factor for yellow;
+y, absence of such a factor; R, presence of factor for smoothness or
+roundness; r, absence of such a factor; &#9794; male; &#9792; female.</p>
+<p>&nbsp;</p>
+
+<p><b>Four Kinds of Gametes in Each Sex Means Sixteen Possible
+Combinations.&mdash;</b>There are, therefore, with reference to the two pairs of
+characters under consideration, four kinds of gametes (or mature
+germ-cells) produced in equal numbers in each hybrid, viz., RY, Ry, rY,
+and ry. That is, in the first type roundness and yellowness are
+associated, in the second roundness and greenness, in the third angularity
+(lack of roundness) and yellowness, and in the fourth angularity and
+greenness.</p>
+
+<p>But since both males and females have these four kinds of gametes, when
+they are mated there will be sixteen possible combinations. These may be
+tabulated as in Fig. 18, opposite <a href="#Page_85">p. 84</a>.</p>
+
+<p><b>The 9:3:3:1 Ratio.&mdash;</b>While there are sixteen possible and equally probable
+combinations, these will give only nine distinct kinds because some of the
+matings are alike. The numbers of the various kinds of matings are as
+follows:</p>
+
+<table border="0" cellpadding="0" cellspacing="0" summary="table">
+<tr><td>(1) 1 RRYY</td>
+    <td><span class="spacer">&nbsp;</span></td>
+    <td>(4) 2 RrYY</td>
+    <td><span class="spacer">&nbsp;</span></td>
+    <td>(7) 1 rrYY</td></tr>
+<tr><td>(2) 2 RRYy</td>
+    <td>&nbsp;</td>
+    <td>(5) 4 RrYy</td>
+    <td>&nbsp;</td>
+    <td>(8) 2 rrYy</td></tr>
+<tr><td>(3) 1 RRyy</td>
+    <td>&nbsp;</td>
+    <td>(6) 2 Rryy</td>
+    <td>&nbsp;</td>
+    <td>(9) 1 rrYy</td></tr></table>
+
+<p>Since roundness (R) and yellowness (Y) are dominant to angularity (r) and
+greenness (y) in all <span class="pagenum"><a name="Page_86" id="Page_86">[Pg 86]</a></span>combinations containing R or Y, the alternative
+determiners r or y would be obscured, with the result that individuals
+having certain of the combinations would look alike to our eye. For
+example, the individuals represented by numbers 1, 2, 4 and 5, since they
+contain dominant R and Y, would all appear round and yellow, although in
+reality No. 1 would be the only one of pure type (both elements
+homozygous) and hence the only one that would breed true in subsequent
+generations. The two individuals represented in No. 2 would breed true as
+regards shape (RR) but not color (Yy). Just the reverse is true of No. 4
+since shape is heterozygous (Rr) and color homozygous (YY). The four
+individuals represented in No. 5 are heterozygous with regard to both
+elements. Thus nine individuals (1 plus 2 plus 2 plus 4 = 9) represented
+in Nos. 1, 2, 4 and 5 would be round and yellow, three individuals (Nos. 3
+and 6) would be round and green, three (Nos. 7 and 8) would be angular and
+yellow, and only one (No. 9) would be angular and green. That is to say,
+the four classes discernible to the eye in generation F<sub>2</sub> would be
+present in the ratio of 9:3:3:1.</p>
+
+<p><b>Phenotype and Genotype.&mdash;</b>Forms such as those represented in Nos. 1, 2, 4
+and 5 which to the eye appear to be alike, regardless of their germinal
+constitution, are said to be of the same <i>phenotype</i>. Those of the same
+hereditary constitution, as the two individuals represented in No. 8, or
+the four individuals in No. 5, are said to be of the same <i>genotype</i>, that
+is, they are of identical gametic constitution.</p>
+
+<p><span class="pagenum"><a name="Page_87" id="Page_87">[Pg 87]</a></span>As we have seen, it is from the genotypical not the phenotypical
+constitution that an offspring is derived and what a given form will bring
+forth depends then on its genotype.</p>
+
+<p><b>Crosses With More Than Two Pairs of Characters.&mdash;</b>In crosses in which more
+than two pairs of contrasted characters are involved the underlying
+principles are in no way different, only with each pair of additional
+characters there is, of course, a greater number of possible combinations.
+Thus with three pairs of characters there will be eight different classes
+of gametes in each sex and consequently sixty-four possible combinations
+in mating, giving eight different phenotypes in the proportion of
+27:9:9:9:3:3:3:1. The largest class manifests the three dominant
+characters; the smallest class, the three recessives; the three classes in
+the proportion of 9 each exhibit two dominant and one recessive
+characters; and those in the proportion of 3 each display two recessive
+and one dominant characters.</p>
+
+
+<p>&nbsp;</p>
+<p class="center">THE QUESTION OF BLENDED INHERITANCE</p>
+
+<p>We come now to certain types of inheritance in which there seems to be a
+true fusion or blend of the contributions from the two parents, the
+intermediate condition apparently persisting in subsequent generations
+without segregation. Numerous cases of blended inheritance have been cited
+in earlier literature of heredity, but as our knowledge of genetics has
+progressed many experimental breeders have come to<span class="pagenum"><a name="Page_88" id="Page_88">[Pg 88]</a></span> believe that the
+blends in such cases are apparent rather than real and that the phenomena
+can be best explained on a non-blending unit-character basis, just as we
+would explain ordinary Mendelian phenomena.</p>
+
+<p><b>Nilsson-Ehle&#8217;s Discoveries.&mdash;</b>To get their point of view we may review
+certain experiments on wheat made by Nilsson-Ehle, together with their
+Mendelian interpretation. Nilsson-Ehle found that a certain brown-chaffed
+wheat when crossed with a white-chaffed strain yielded a brown-chaffed
+hybrid, apparently in accordance with the simple principle of Mendelian
+dominance. But these heterozygous brown-chaffed individuals did not in
+turn give the expected ratio of 3:1 in the F<sub>2</sub> generation but a ratio of
+15 brown to 1 white, and furthermore the browns were not all of the same
+degree of brownness. To be exact, from fifteen different crosses of the
+strains he obtained 1,410 brown-chaffed and 94 white-chaffed plants.</p>
+
+<p>This apparent anomaly in segregation was easily explained, however, when
+it was finally figured out that there were really two independent
+determiners for brown color, either of which alone could produce a brown
+individual, but when combined produced individuals of correspondingly
+deeper shades of brown. In such a case then Nilsson-Ehle discovered that
+he was dealing merely with a Mendelian dihybrid where two different
+determiners B and B&prime; and their respective absences b and b&prime; are involved.
+The original brown wheat had both B and B&prime; and the original white b and
+b&prime;. The formula for the F<sub>1</sub> heterozygote was therefore BbB&prime;b&prime;. The four
+possible types of gametes<span class="pagenum"><a name="Page_89" id="Page_89">[Pg 89]</a></span> for male and female are BB&prime;, Bb&prime;, bB&prime;, bb&prime;, and
+the tabulation would be as follows:</p>
+
+<table border="0" cellpadding="0" cellspacing="0" summary="table">
+<tr><td class="br">&nbsp;</td>
+    <td class="btr" align="center">BB&prime;</td>
+    <td class="btr" align="center">Bb&prime;</td>
+    <td class="btr" align="center">bB&prime;</td>
+    <td class="bt" align="center">bb&prime;</td></tr>
+<tr><td class="btr" align="center">BB&prime;</td>
+    <td class="btr" align="center">BBB&prime;B&prime;</td>
+    <td class="btr" align="center">BBB&prime;b&prime;</td>
+    <td class="btr" align="center">BbB&prime;B&prime;</td>
+    <td class="bt" align="center">BbB&prime;b&prime;</td></tr>
+<tr><td class="btr" align="center">Bb&prime;</td>
+    <td class="btr" align="center">BBB&prime;b&prime;</td>
+    <td class="btr" align="center">Bb&prime;Bb&prime;</td>
+    <td class="btr" align="center">BbB&prime;b&prime;</td>
+    <td class="bt" align="center">Bbb&prime;b&prime;</td></tr>
+<tr><td class="btr" align="center">bB&prime;</td>
+    <td class="btr" align="center">BbB&prime;B&prime;</td>
+    <td class="btr" align="center">BbB&prime;b&prime;</td>
+    <td class="btr" align="center">bbB&prime;B&prime;</td>
+    <td class="bt" align="center">bbB&prime;b&prime;</td></tr>
+<tr><td class="btr" align="center">bb&prime;</td>
+    <td class="btr" align="center">BbB&prime;b&prime;</td>
+    <td class="btr" align="center">Bbb&prime;b&prime;</td>
+    <td class="btr" align="center">bbB&prime;b&prime;</td>
+    <td class="bt" align="center">bbb&prime;b&prime;</td></tr>
+<tr><td class="bt">&nbsp;</td>
+    <td class="bt">&nbsp;</td>
+    <td class="bt">&nbsp;</td>
+    <td class="bt">&nbsp;</td>
+    <td class="bt">&nbsp;</td></tr></table>
+
+<p>It will be observed that there are more brown determiners in some
+combinations than others. For instance one of the sixteen contains four
+such determiners, viz., B, B&prime;, B, B&prime;, four contain three determiners, six
+contain two, four contain only one, and one contains none. Thus all but
+one of the sixteen contain at least one determiner and will therefore be
+brown in color but the depth of color will depend on the number of brown
+determiners in a given individual. This is more graphically represented in
+Fig. 19, <a href="#Page_90">p. 90</a>. The largest number of similar individuals, six in all,
+contain two determiners each and represent an intermediate &#8220;blend&#8221; between
+the original brown-chaffed and white-chaffed strains. The deeper and the
+lighter browns due to more or fewer determinants in an individual would if
+one did not know the units in this case look like the fluctuations around
+this average which we might expect in a blend.</p>
+
+
+<p>&nbsp;<span class="pagenum"><a name="Page_90" id="Page_90">[Pg 90]</a></span></p>
+<div class="figcenter"><img src="images/img19.jpg" alt="" /></div>
+<p class="center"><span class="smcap">Fig. 19</span></p>
+
+<p class="descrip">Diagram illustrating the proportionate distribution of determiners where
+either of two different determiners produces the same character, the
+degree of expression of the character depending on the number of the
+determiners present. The numerals indicate the number of brown determiners present in an individual.</p>
+<p>&nbsp;</p>
+
+<p>Nilsson-Ehle found another significant case in wheat where one particular
+red-grained strain of Swedish wheat when crossed with white-grained
+strains produced red-grained offspring, but when these were interbred the
+F<sub>2</sub> generation gave approximately sixty-three red to one white-grained
+individual. Here it was<span class="pagenum"><a name="Page_91" id="Page_91">[Pg 91]</a></span> found that in the original red wheat there are
+three separate determiners which act independently of one another in
+heredity, any one of which would make red color; and that they together
+with their absences simply follow the Mendelian laws for a trihybrid.</p>
+
+<p><b>Such Cases Easily Mistaken for True Blends.&mdash;</b>If we should tabulate the
+possible combinations as we did the dihybrid we should see that we would
+get individuals having varying numbers of red determiners. Only one of the
+sixty-four possible combinations would be without a factor for red. Of the
+sixty-four, one would have six determiners for red, six would have five,
+fifteen would have four, twenty would have three, fifteen would have two,
+six would have one, and one would have none. Since here every additional
+red factor means deeper redness in the individual there would be varying
+degrees of redness in the F<sub>2</sub> generation with those having three
+determiners, the largest group, standing apparently intermediate. Not
+knowing the factors involved we might easily mistake such a case for a
+true blend with fluctuations about an average intermediate form.
+Nilsson-Ehle finally proved his interpretation by rearing an F<sub>3</sub>
+generation from isolated and self-fertilized plants of this F<sub>2</sub>
+generation.</p>
+
+<p>This same principle of cumulative determiners has also been established in
+America by East with field corn.</p>
+
+<p>As the number of duplicate determiners increases it can be readily seen
+that the number of apparent blends of different degrees of intermediacy
+between the two extremes would rapidly increase.</p>
+
+<p><span class="pagenum"><a name="Page_92" id="Page_92">[Pg 92]</a></span><b>Skin-Color in Man.&mdash;</b>In man, the skin-color of the hybrids between negroes
+and whites is often cited as a case of blended inheritance in
+contradistinction to Mendelian inheritance. The skin-color of the mulatto
+of the F<sub>1</sub> generation is intermediate between that of the white and
+black parent. This same degree of intermediacy is commonly supposed to
+persist in subsequent generations, but as a matter of fact, careful
+investigation has shown that while mulattoes rarely produce pure white or
+pure black children, there is considerably greater range in the shades of
+color in the F<sub>2</sub> generation and subsequent generations than in the F<sub>1</sub>
+generation. This is exactly what one would expect of a Mendelian character
+in which several cooperating factors were involved. Indeed, Davenport who
+has made extensive studies<a name='fna_3' id='fna_3' href='#f_3'><small>[3]</small></a> on the inheritance of skin-color in man has
+come to the conclusion that the case is really one of Mendelian
+inheritance in which several factors for skin-color are concerned. Even
+the skin of a white man is pigmented in some degree under normal
+conditions. Davenport has shown in the skin of both whites and blacks that
+there is a mixture of black, yellow and red pigments. He concludes that
+&#8220;there are two double factors (AABB) for black pigmentation in the
+full-blooded negro of the west coast of Africa and these are separably
+inheritable.&#8221; Since these factors are lacking in white persons the
+intermediate color of an F<sub>1</sub> mulatto would therefore be heterozygous for
+pigmentation, and <span class="pagenum"><a name="Page_93" id="Page_93">[Pg 93]</a></span>subsequent generations, following the laws for
+segregation where a number of factors are concerned, would show different
+degrees of color because of the varying combinations of factors.</p>
+
+<p><b>Some Investigators Would Question the Existence of Real Blends.&mdash;</b>Still
+other reputed blends such as ear length in rabbits and the like have been
+shown to be analyzable into Mendelian behavior if one will but postulate
+numerous or multiple factors. Just how far we are justified in so
+accounting for blends has not yet been established. Some of our most
+careful experimentalists in heredity still believe that real blends exist,
+particularly where the character is quantitatively expressed&mdash;that is, as
+more or less of a given size or amount&mdash;while others would maintain that
+all alleged blends will probably be found to be resolvable into factors
+which follow Mendelian rule. It must be left for future investigations to
+demonstrate which school is correct.</p>
+
+
+<p>&nbsp;</p>
+<p class="center">THE PLACE OF THE MENDELIAN FACTORS IN THE GERM-CELLS</p>
+
+<p><b>Parallel Between the Behavior of Mendelian Factors and Chromosomes.&mdash;</b>The
+question arises as to whether there is any evidence from the study of
+germ-cells themselves to bear out the Mendelian conception of separation
+of contrasted characters in the gametes of the F<sub>1</sub> generation. In the
+discussion of the maturation of germ-cells (<a href="#CHAPTER_II">Chap. II</a>) it has already been
+seen that the chromosomes of the germ-cells are in all probability
+arranged in homologous pairs, one member being<span class="pagenum"><a name="Page_94" id="Page_94">[Pg 94]</a></span> of maternal and the other
+of paternal origin, and that furthermore they are closely associated with
+the phenomena of heredity. And since in maturation there is an actual
+segregation of the chromosomes into two sets, half going to one cell and
+half to its mate, a physical basis adequate to the necessities of the case
+is really at hand. It will be recalled that the individuals of a pair
+separate in such a way at the reduction division that the paternal member
+goes to one cell and the maternal member to the other, although each pair
+seemingly acts independently of the others with the result that any mature
+germ-cell may contain chromosomes from each of the original parents but
+never the two chromosomes which earlier made up a pair. The close parallel
+between the behavior of chromosomes and the behavior of Mendelian factors,
+although the two sets of phenomena were discovered wholly independently of
+each other, is obvious. If we suppose that each chromosome bears the
+determiner of a Mendelian character and that chromosomes bearing
+allelomorphic characters make up the various pairs which are seen in the
+early germ-cells of an individual before reduction occurs, then the
+segregation of the individuals of an allelomorphic pair into different
+gametes must result in consequence of the passing of the corresponding
+chromosomes into separate gametes. Fig. 20, <a href="#Page_95">p. 95</a>, from Professor Wilson
+represents equally well the segregations of pairs of chromosomes or pairs
+of Mendelian characters.</p>
+
+<p>&nbsp;<span class="pagenum"><a name="Page_95" id="Page_95">[Pg 95]</a></span></p>
+<div class="figcenter"><img src="images/img20.jpg" alt="" /></div>
+<p class="center"><span class="smcap">Fig. 20</span></p>
+
+<p>Diagram showing union of factors from the two separate parents in
+fertilization and their segregation in the formation of germ-cells (after
+Wilson). With four pairs of factors (<i>Aa</i>, <i>Bb</i>, <i>Cc</i>, <i>Dd</i>), sixteen
+types of gametes are possible, as shown in the series of small circles at
+the right. The same diagram equally well represents the pairings and segregations of chromosomes.</p>
+<p>&nbsp;</p>
+
+<p><b>A Single Chromosome not Restricted to Carrying a Single Determiner.&mdash;</b>It
+has been objected that there may be more pairs of independently heritable
+allelomorphic characters than there are pairs of chromosomes. It is true
+that there are more pairs of characters than pairs of chromosomes but
+there is no reason for supposing that a given chromosome is restricted to
+carrying a single unit-determiner. On the contrary it probably carries
+several or many. Some workers have pointed out that certain units might be
+interchanged during the pairing of chromosomes <span class="pagenum"><a name="Page_96" id="Page_96">[Pg 96]</a></span>before the reduction
+division, others that inasmuch as the chromosomes become diffuse and
+granulated during the intervals between divisions it is not improbable
+that the individual units may become separated from their original system
+during such times and that it is a matter of chance into which of the
+homologous chromosomes, A or a, they enter with the re-establishment of
+the chromosomes. On the other hand, cases are known where two or more
+separate characters are permanently associated in inheritance, that is, if
+they enter a crossed form together they come out together in the
+grandchildren as if they were carried in the same unit-body in the
+germ-cell. The only observable unit-bodies that fulfil the necessities of
+such cases are the chromosomes. This tendency of characters to exist in
+groups which are inherited independently of one another is coming more and
+more into evidence as we penetrate farther into the intricacies of
+inheritance, and it is exactly what we would expect on the supposition
+that each chromosome carries the determiners of a number of characters
+instead of a single one.</p>
+
+
+
+<p>&nbsp;</p><p>&nbsp;</p>
+<hr style="width: 50%;" />
+<p><span class="pagenum"><a name="Page_97" id="Page_97">[Pg 97]</a></span></p>
+<h2><a name="CHAPTER_IV" id="CHAPTER_IV"></a>CHAPTER IV</h2>
+<p class="title">MENDELISM IN MAN</p>
+
+
+<p><b>The Mendelian Principles Probably Applicable to Many Characters of
+Man.&mdash;</b>We are really just beginning to make the proper observations and
+collect the necessary data with reference to the application of Mendelian
+principles to the traits of man. Yet brief as has been our study we have
+disclosed much significant evidence which makes it seem highly probable
+that many of his characters, good and bad, of mind and body are as
+subservient to these laws as are the traits and features of lower forms.
+Davenport and Plate record over sixty human characters or defects which
+are seemingly inherited in Mendelian fashion. Although about fifty of
+these are pathological or abnormal conditions, this does not mean that
+such conditions are more prone to follow Mendelian inheritance but merely
+that being relatively conspicuous or isolated they are easier to follow
+and tabulate.</p>
+
+<p><b>Difficult to get Correct Data.&mdash;</b>While it must be said that in many cases
+no simple form of Mendelian tabulation has been unequivocally established,
+yet the general behavior of the various inheritable traits in question is
+so obviously related to the conventional Mendelian course that there seems
+little reason for doubting that they are at bottom the same. Failure to
+obtain exact proportions may be attributable in part<span class="pagenum"><a name="Page_98" id="Page_98">[Pg 98]</a></span> to the probability
+that what we loosely regard as a character should in reality be analyzed
+into more elemental components, and above all to the fact that from the
+very nature of the conditions under which human records must be obtained,
+there is considerable chance of inaccuracy or error in such accounts. How
+many human traits follow Mendelian rules remains largely for future
+investigators to establish.</p>
+
+<p>We are handicapped at the outset in man by the many difficulties of
+getting correct data from the genealogies on which we must depend, or in
+fact of getting any genealogy at all, for in this country at least, most
+families keep imperfect records of births and deaths and many of the
+institutions for the various kinds of defectives have little in their
+records that will help us in following out hereditary conditions. Then in
+matters of disease we meet with the fact that many former diagnoses were
+erroneous. In yet other cases, and this is particularly true among mental
+and moral defectives, we are often not sure of the paternity of a given
+child. Furthermore, one is likely to be misled by the proportions which
+may occur in the very limited number of children of any given couple.</p>
+
+<p>Still other difficulties exist. Among these is the fact, for example, that
+in many cases of defect or susceptibility to disease, a given individual
+in the stock may have the trait in an expressible and transmissible form,
+yet it never comes to expression because that individual has been
+fortunate enough to escape the environmental stimulus which would call it
+forth. Thus one highly susceptible to tuberculosis might escape infection,
+or persons hovering on the verge of insanity<span class="pagenum"><a name="Page_99" id="Page_99">[Pg 99]</a></span> might never receive the
+precipitating stimulus which would topple them into actual insanity; yet
+each would be wrongfully recorded in a genealogy looking to such traits as
+perfectly normal. Or again if it be a question of intellectual brilliancy
+as shown by accomplishment in the realm of scholarship, or of worldly
+affairs, the ones who although possessing them have had no chance to
+display unusual talents would be tabulated as average whereas in fact they
+should be recorded as of high rank. That this is particularly likely to
+happen in the case of women is evident.</p>
+
+<p><b>A Generalized Presence-Absence Formula for Man.&mdash;</b>In man as in lower forms
+some characters or traits are due presumably to the presence of
+determiners or to their absence. Likewise, dominance and recessiveness are
+as much in evidence, for in tracing back pedigrees of various traits we
+find the same forms of tabulation that obtain for these conditions in
+plants and lower animals hold good. For typical cases in man let us use a
+generalized presence-absence formula and the arbitrary symbol A for the
+presence of the determiner of the character (double in the individual,
+single in the germ) and a for its absence. Thus AA represents a condition
+in which similar determiners have been derived from both parents and the
+individual is <i>duplex</i> as regards the character in question; each mature
+germ-cell will have the determiner. Aa represents a condition in which the
+individual has received the determiner from only one parent and is
+therefore <i>simplex</i> with regard to the character; half of the gametes of
+such an individual will have the determiner and half will lack it. Lastly,
+aa represents total <span class="pagenum"><a name="Page_100" id="Page_100">[Pg 100]</a></span>absence of the determiner. Such an individual is
+<i>nulliplex</i>. He or she will not have the determiner represented in any of
+the gametes, and can not, of course, transmit a trait represented by the
+determiner.</p>
+
+<p>It is evident that six kinds of gametic matings are possible among
+individuals representing these various formul&aelig;. These matings are as
+follows:</p>
+
+<table border="0" cellpadding="0" cellspacing="0" summary="table">
+<tr><td valign="bottom" align="center">Matings</td>
+    <td valign="bottom" align="center">Possible<br />couplings<br />gametes</td>
+    <td>&nbsp;</td>
+    <td valign="bottom" align="center">Product</td></tr>
+<tr><td valign="top">1. Nulliplex x Nulliplex (aa x aa) ==&nbsp;</td>
+    <td align="center" valign="top"><img src="images/page100a.jpg" alt="" /></td>
+    <td valign="top">&nbsp;==</td>
+    <td valign="top">&nbsp; all nulliplex</td></tr>
+<tr><td>&nbsp;</td></tr>
+<tr><td valign="top">2. Nulliplex x Simplex (aa x Aa) ==&nbsp;</td>
+    <td align="center" valign="top"><img src="images/page100b.jpg" alt="" /></td>
+    <td valign="top">&nbsp;==</td>
+    <td valign="top">&nbsp; 50 per cent.<br />with character<br />nulliplex and<br />50 per cent.<br />with it simplex.</td></tr>
+<tr><td>&nbsp;</td></tr>
+<tr><td valign="top">3. Nulliplex x Duplex (aa x AA) ==&nbsp;</td>
+    <td align="center" valign="top"><img src="images/page100c.jpg" alt="" /></td>
+    <td valign="top">&nbsp;==</td>
+    <td valign="top">&nbsp; all with<br />characters<br />simplex</td></tr>
+<tr><td>&nbsp;</td></tr>
+<tr><td valign="top">4. Simplex x Simplex (Aa x Aa) ==&nbsp;</td>
+    <td align="center" valign="top"><img src="images/page100d.jpg" alt="" /></td>
+    <td valign="top">&nbsp;==</td>
+    <td valign="top">&nbsp; 25 per cent.<br />with characters<br />duplex, 50 per<br />cent. with it<br />simplex and 25<br />per cent. with<br />it nulliplex.</td></tr>
+<tr><td>&nbsp;</td></tr>
+<tr><td valign="top">5. Simplex x Duplex (Aa x AA) ==&nbsp;</td>
+    <td align="center" valign="top"><img src="images/page100e.jpg" alt="" /></td>
+    <td valign="top">&nbsp;==</td>
+    <td valign="top">&nbsp;50 per cent.<br />with character<br />duplex and 50<br />per cent. with<br />it simplex.</td></tr>
+<tr><td>&nbsp;</td></tr>
+<tr><td valign="top">6. Duplex x Duplex (AA x AA) ==&nbsp;</td>
+    <td align="center" valign="top"><img src="images/page100f.jpg" alt="" /></td>
+    <td valign="top">&nbsp;==</td>
+    <td valign="top">&nbsp; all duplex.</td></tr></table>
+
+<p><b>Indications of Incomplete Dominance.&mdash;</b>While in cases of strict Mendelian
+dominance it is not possible<span class="pagenum"><a name="Page_101" id="Page_101">[Pg 101]</a></span> to distinguish directly the simplex from the
+duplex condition, as a matter of fact the individual of simplex
+constitution sometimes has the character represented in the single
+determiner less perfectly developed than in the corresponding character of
+
+duplex origin. In studying defects in man due to the absence of a
+determiner, where theoretically presence of the determiner (normality) is
+dominant over its absence in individuals of simplex constitution, one
+finds it recorded with increasing frequency that such individuals are more
+or less &#8220;intermediate&#8221; or are &#8220;tainted&#8221; with the defect; thus showing that
+the defect though obscured is not wholly in abeyance. Thus individuals
+carrying epilepsy or feeble-mindedness which are regarded as recessive
+traits, while not showing specific feeble-mindedness or epilepsy, may
+nevertheless apparently show a neuropathic taint in the form of migraine,
+alcoholism or other lapse from normality. The condition is seemingly more
+akin in some cases to that found in the offspring of certain red flowers
+crossbred with white flowers, which though red do not show the same
+intensity of color as the original red parent. Just as here the single
+determiner or single &#8220;dose&#8221; of redness is insufficient to produce the
+intensity of color that appears when the offspring receive two determiners
+for red, one from each parent, so in man a single determiner for normality
+of a specific character is inadequate in some cases to make the individual
+wholly normal. Or possibly some cases are more of the type of those in
+which the character in question, for instance the red color of some wheats
+and corn, may be produced by any one of two or three determiners, the
+intensity of<span class="pagenum"><a name="Page_102" id="Page_102">[Pg 102]</a></span> the characters (red color, e. g.) depending on whether one,
+two or three determiners are present.</p>
+
+<p><b>Why After the First Generation Only Half the Children May Show the
+Dominant Character.&mdash;</b>If the trait is a simple dominant one it is clear
+that it will appear in each generation and always spring from an affected
+individual. By referring back to our tabulation of possible matings on
+page 100 where the dominant character is represented by the letter A, this
+can be seen at a glance. If the trait is present in the duplex condition
+in one parent and absent from the other, then formula 3 applies; all
+children will show the trait, but in the simplex form (Aa). If the trait
+is present in the simplex form in one parent and absent in the other,
+formula 2 applies. Fifty per cent. of the children will have the character
+in the simplex form (Aa) which means also an even chance of transmitting
+it to their offspring; fifty per cent. will not inherit it and will be
+incapable, furthermore, of transmitting it, since they have become
+nulliplex (aa). In human genealogies if an individual having an unusual
+trait which is inherited as a dominant marries a normal person and half of
+the offspring show the trait (and this is common), this means that the
+parent manifesting the trait had it represented only in the simplex
+condition, otherwise all of the children would have shown it. Even though
+the original ancestor who first developed the condition or structure may
+have had it in a duplex form, it would after the first mating, if this
+were with an individual lacking the trait, be represented only in the
+simplex form (see formula 5) and could never become duplex again unless
+two <span class="pagenum"><a name="Page_103" id="Page_103">[Pg 103]</a></span>individuals both having the character married, and then only in
+twenty-five per cent. of the offspring (see formula 3). If the trait is a
+defect all the children showing it, even though marrying normal
+(nulliplex) individuals, will pass it on again to half their children, but
+those who do not show it may ordinarily marry with impunity since its
+non-expression in their make-up means, as far as we know at present, that
+their germ-plasm has been purged of the defect and that they are therefore
+nulliplex with reference to it.</p>
+
+<p><b>Eye-Color in Man.&mdash;</b>Of normal characters in man which follow the Mendelian
+formula perhaps eye-color is the best established. Brown or black
+eye-color is due to a <i>melanin</i> pigment absent from the blue or gray eye.
+That is, a brown eye is practically a blue eye plus an additional layer of
+pigment on the outer surface of the iris. The different shades of brown
+and the black are due to the relative abundance of this pigment. Gray
+color and the shades of blue seem to be a modification of an original dark
+blue, due to structural differences in the fibrous tissues of the iris.</p>
+
+<p>In inheritance brown or black is dominant to blue or gray, or in other
+words the <i>presence</i> and <i>absence</i> of a pigment P constitutes a pair of
+allelomorphs. Hence two brown-eyed parents, if P is duplex in both (or
+duplex in one and simplex in the other) can have only brown-eyed children.
+Thus,</p>
+
+<div class="blockquot"><p>1. PP &times; PP = PP, or all duplex brown.</p>
+
+<p>2. PP &times; Pp = PP and Pp, half duplex brown and half simplex brown.</p></div>
+
+<p>If each parent has brown eyes but in simplex <span class="pagenum"><a name="Page_104" id="Page_104">[Pg 104]</a></span>condition, then one-fourth
+of children will have blue or gray eyes; for example,</p>
+
+<table border="0" cellpadding="0" cellspacing="0" summary="table">
+<tr><td align="center" valign="top">Mating</td>
+    <td>&nbsp;</td>
+    <td align="center">Gametic<br />couplings</td>
+    <td>&nbsp;</td>
+    <td align="center" valign="top">Product</td></tr>
+<tr><td valign="top">Pp &times; Pp</td>
+    <td valign="top">&nbsp; == &nbsp;</td>
+    <td align="center" valign="top"><img src="images/page104.jpg" alt="" /></td>
+    <td valign="top">&nbsp; == &nbsp;</td>
+    <td valign="top">PP, Pp, pP, and pp, or one-fourth<br />duplex brown, one-half simplex<br />brown, and one-fourth blue or gray.</td></tr></table>
+
+<p>If both parents have blue or gray eyes they can not have children with
+black or brown eyes, since the recessive condition in each parent means
+total absence of brown pigment in both.</p>
+
+<p>If one pair is duplex brown and the other blue, then all children will
+have brown eyes but of simplex type.</p>
+
+<p>If one parent has simplex brown eyes (type Pp) and one blue (pp) then
+one-half of the children will have brown eyes of simplex type and one-half
+will have blue eyes.</p>
+
+<p>Occasional objections have been raised against the Mendelian
+interpretation of inheritance in eye-color, but the cases cited in
+evidence against the theory usually narrow down to those in which the
+color is so diluted as to render classification uncertain. For example,
+hazel eyes are sometimes called gray; they belong however to the melanic
+pigmented type although the brown pigment may be much diluted and occur
+mainly around the pupil. So-called green eyes are due to yellow pigment on
+a blue background. In the rare cases where in the same individual one eye
+is brown and the other blue, the individual should probably be rated as
+brown-eyed on the supposition that in the one eye the development of brown
+pigment has in some way been suppressed.</p>
+
+<p><span class="pagenum"><a name="Page_105" id="Page_105">[Pg 105]</a></span><b>Hair-Color.&mdash;</b>The inheritance of hair-color has also been the subject of
+considerable study and while the conditions are not so simple as in the
+case of eye-color, there is little doubt that it belongs in the Mendelian
+category. In human hair, color has as its foundation apparently two
+pigments, black and red. Absence of one or both or various combinations or
+dilutions of these seemingly account for the prevailing colors in human
+hair. In general dark hair is dominant to light, although because of the
+delay sometimes in the darkening of the hair in children this fact is
+often obscured. Black is dominant to red. People with glossy black hair,
+according to Davenport, are probably simplex for black, the glossiness
+being due usually to recessive red. The expectation would be for some of
+the children of such a pair to have red hair.</p>
+
+<p>In man occasionally a congenital white lock contrasting strikingly with
+the remaining normally pigmented hair occurs. It behaves as a simple
+dominant in heredity.</p>
+
+<p><b>Hair-Shape.&mdash;</b>Again, straight and curly hair seem to be distinct
+inheritable characters. Curly is incompletely dominant to straight, the
+simplex condition yielding wavy hair.</p>
+
+<p>Not to enter into details of the matings, statistics gathered by Mr. and
+Mrs. Davenport show that, two flaxen-haired parents have flaxen-haired
+children; two golden-haired parents have only golden-haired children; two
+parents with light brown hair have children with hair of that color or
+lighter, but never darker; two parents each with dark brown or black hair
+may have children with all the varieties of hair-color. <span class="pagenum"><a name="Page_106" id="Page_106">[Pg 106]</a></span>Summing together
+a series of recessives Davenport points out that two blue-eyed, flaxen or
+golden and straight-haired parents will have only children like
+themselves.</p>
+
+<p>&nbsp;</p>
+<div class="figcenter"><img src="images/img21.jpg" alt="" /></div>
+<p class="center"><span class="smcap">Fig. 21</span></p>
+
+<p class="descrip">Diagram showing descent of brachydactyly through five generations; black
+symbols indicate affected individuals; &#9794;, male; &#9792;, female (after Farabee).</p>
+<p>&nbsp;</p>
+
+<p><b>Irregularities.&mdash;</b>If a dominant trait or defect depends on more than a
+single factor, as is sometimes the case, or if it is modified by sex or
+other conditions, as is true of certain characters, some of which, such as
+color-blindness, have already been examined, then we shall find some
+apparently non-affected individuals having affected offspring. Certain
+diseases, for example, are generally transmitted by affected members of
+the family to their children in the expected Mendelian ratio for a
+dominant, yet an occasional skip of a generation may appear in which an
+apparently perfectly normal individual transmits to his children what,
+except for the omission in his own case, appears to be an ordinary
+dominant character.<span class="pagenum"><a name="Page_107" id="Page_107">[Pg 107]</a></span> This occasional lapse in the appearance of a
+character when theoretically it should appear is doubtless due in some
+instances to the fact that what is really inherited is a <i>tendency</i>, and
+although this is present in the apparently normal individual, for some
+reason the condition itself has not appeared. This might especially be
+true in the case of a disease which does not manifest itself until late in
+life. In other cases there are undoubtedly complicating accessory
+conditions which modify the behavior of the trait somewhat.</p>
+
+
+<p>&nbsp;</p>
+<p class="center">OTHER CASES OF DOMINANCE IN MAN</p>
+
+<p>Among other normal characters in man, as far as available evidence goes,
+dark skin is dominant to light skin; normally pigmented condition to
+albino; and nervous temperament to phlegmatic.</p>
+
+<p><b>Digital Malformations.&mdash;</b>An interesting and easily followed defect is a
+condition known as <i>brachydactylism</i>, in which the digits are shortened
+because of the absence or rudimentary condition of one segment. The
+fingers, therefore, appear to be only two-jointed like the thumb. Several
+families showing this defect have been charted and it appears to behave as
+a typical dominant. In looking over such a chart (Fig. 21, <a href="#Page_106">p. 106</a>) one is
+struck by the fact that only half of the children from most of the matings
+show the defect, but when we recall that the affected parent, after the
+first generation, probably carried the condition in only the simplex form
+and married a normal individual, such a result is just what would be
+expected (see formula 2).</p>
+
+<p><span class="pagenum"><a name="Page_108" id="Page_108">[Pg 108]</a></span><i>Polydactylism</i> (Figs. 22, 23, <a href="#Page_109">pp. 109</a>,
+<a href="#Page_110">110</a>) is a condition in which there are extra digits on hands or feet. The character, with apparently slight
+exceptions in a few records, behaves as a typical dominant. Among other
+digital defects which are inherited as a dominant is a condition known as
+<i>syndactylism</i> (Fig. 24, <a href="#Page_111">p. 111</a>), in which two or more digits are fused
+side by side. For an example of syndactyly which seems to be in the class
+of sex-linked characters, see Fig. 15, <a href="#Page_65">p. 65</a>.</p>
+
+<p><b>Eye Defects.&mdash;</b><i>Congenital cataract</i> is another not uncommon defect in man
+which is transmitted as a dominant (Fig. 25, <a href="#Page_112">p. 112</a>) with occasional
+irregularities. It is a condition of opacity of the lens of the eye which
+produces partial or total blindness. In a paper on <i>Hereditary Blindness
+and Its Prevention</i>, Clarence Loeb (1909) mentions 304 families of which
+pedigrees have been published. Of the 1,012 children in these families
+589, or 58 per cent., were affected. It is obvious that this is near the
+expected percentage in the case of a dominant trait where matings of
+affected with normal individuals prevailed. An unfortunate circumstance
+about this malady from the eugenic standpoint is the fact that it is
+frequently of the presenile form which comes on late in life so that it is
+usually impossible to predict whether an individual of marriageable age is
+immune or will later become affected.</p>
+
+<p>&nbsp;<span class="pagenum"><a name="Page_109" id="Page_109">[Pg 109]</a></span></p>
+<div class="figcenter"><img src="images/img22.jpg" alt="" /></div>
+<p class="center"><span class="smcap">Fig. 22</span></p>
+
+<p class="descrip">Radiograph (Courtesy of Dr. W. B. Helm) showing polydactyly in a child&#8217;s
+hand. For genealogy of this see Fig. 23, <a href="#Page_110">p. 110</a>.</p>
+
+<p>&nbsp;<span class="pagenum"><a name="Page_110" id="Page_110">[Pg 110]</a></span></p>
+<div class="figcenter"><img src="images/img23.jpg" alt="" /></div>
+<p class="center"><span class="smcap">Fig. 23</span></p>
+
+<p class="descrip">Chart showing a history of polydactylism through five generations in the
+B&mdash;&mdash; family. The individual whose hand is pictured in Fig. 22, <a href="#Page_109">p. 109</a>, is
+of the fifth generation. Squares represent males, circles females.</p>
+<p>&nbsp;</p>
+
+<p>Another defect of the eye following the course of a dominant in heredity
+is a pigmentary degeneration of the retina known as <i>retinitis
+pigmentosa</i>. Atrophy of the optic nerve is also involved and the final
+result is blindness. Still another example frequently cited is that of
+hereditary night blindness (<i>hemeralopia</i>), a disease in which the
+affected person can not see by any but the brightest light. In most
+affected families the final outcome is usually total blindness. One of the
+most remarkable pedigrees of defects in man ever collected is one of this
+disease published by Nettleship. He succeeded in tracing the defect
+through nine generations, back to the seventeenth century. The genealogy
+includes 2,116 persons. The character behaves as a single dominant in
+males, but frequently, though <span class="pagenum"><a name="Page_111" id="Page_111">[Pg 111]</a></span>not always, females may be carriers of the
+defect in transmissible form though not exhibiting it themselves. That is,
+males in which the condition is simplex (Aa) develop the defect but
+females of similar simplex constitution (Aa) frequently do not. It
+follows, therefore, that normal males of such strains will have normal
+offspring but normal females may have affected children.</p>
+
+<p>&nbsp;</p>
+<div class="figcenter"><img src="images/img24.jpg" alt="" /></div>
+<p class="center"><span class="smcap">Fig. 24</span></p>
+
+<p class="descrip">Radiograph (Courtesy of Dr. W. B. Helm) showing a partial syndactyly in
+each hand of an individual. Some degree of webbing between the more distal
+portions of the affected parts is usual.</p>
+
+<p>&nbsp;<span class="pagenum"><a name="Page_112" id="Page_112">[Pg 112]</a></span></p>
+<div class="figcenter"><img src="images/img25.jpg" alt="" /></div>
+<p class="center"><span class="smcap">Fig. 25</span></p>
+
+<p class="descrip">Pedigree of a family with presenile cataract (black symbols); numbers in
+circles indicate unaffected individuals (after Davenport).</p>
+<p>&nbsp;</p>
+
+<p><b>Other Defects Inherited as Dominants.&mdash;</b>Not to go into details other
+defects which behave as dominants or modified dominants in human
+inheritance may be mentioned. The following list is not complete and it
+must be understood that in some cases the statistics are insufficient to
+justify us in making anything but a tentative decision. We may thus
+enumerate as dominant<span class="pagenum"><a name="Page_113" id="Page_113">[Pg 113]</a></span> over normality: <i>Achondroplasy</i> (abnormally short
+limbs with normal head and body); <i>Keratosis</i> (thickening of epidermis);
+<i>Epidermolysis</i> (excessive formation of blisters); <i>Hypotrichosis</i>
+(hairless, toothless condition); <i>Diabetes insipidus</i>; <i>Diabetes
+mellitus</i>; ordinary (not Gower&#8217;s) <i>muscular atrophy</i>; <i>Glaucoma</i> (internal
+swelling and pressure of eye-ball); displaced lens; <i>Coloboma</i> (open
+suture in iris); spottedness of hair-coat; and corneal opacity.</p>
+
+<p>As a final illustration of a serious malady in man which acts as a
+dominant in inheritance, let us take <i>Huntington&#8217;s chorea</i>. Ordinary
+<i>chorea</i>, or St. Vitus&#8217; dance, a disorder characterized by involuntary
+muscular movements, is commonly though not always confined to children and
+usually ends in recovery, but <i>Huntington&#8217;s chorea</i> appears typically in
+middle life and is a much more dangerous malady. Fig. 26, <a href="#Page_114">p. 114</a>,
+represents the family history of one of five cases which have been studied
+by Doctor Lorenz in the Mendota Hospital for the Insane. All charts which
+have been platted of this malady show it to be inherited as a dominant.
+This means that half of the children of an individual who carried the
+malady in the simplex condition, and all the children of one who carries
+it in the duplex condition, are probably marked for this terrible end. And
+the true horror of it can only be appreciated by one who has seen the last
+stages of the malady. The victim once in its grasp gradually becomes
+wrecked in mind and body; the muscular twitchings and disorders of
+movement continually increase and dementia progresses until at last death
+ensues. Fig.<span class="pagenum"><a name="Page_114" id="Page_114">[Pg 114]</a></span> 27, <a href="#Page_116">p. 115</a>, is another chart showing inheritance of
+<i>Huntington&#8217;s chorea</i>. In still a third case at the Mendota Hospital, the
+gravity of the situation can be appreciated when one realizes that the
+patient is the father of ten children, ranging in age from one to
+seventeen and one-half years. The calamitous fact that this disease does
+not manifest itself usually until middle life makes it likely that these
+children will all reach maturity, marry and in turn probably produce
+offspring before the doomed members of the family realize their fate.</p>
+
+
+<p>&nbsp;</p>
+<div class="figcenter"><img src="images/img26.jpg" alt="" /></div>
+<p class="center"><span class="smcap">Fig. 26</span></p>
+
+<p class="descrip">Chart showing descent of <i>Huntington&#8217;s chorea</i> in the P&mdash;&mdash; family
+(courtesy of Dr. W. F. Lorenz). Squares represent male, circles female;
+shaded figures are choreic members of the family; partially shaded
+figures, slightly affected or very &#8220;nervous&#8221; members. The members of the
+last generation are for the most part still too young to show their
+condition. The cross indicates the individual in the asylum from whom the record was traced back.</p>
+
+
+<p>&nbsp;<span class="pagenum"><a name="Page_115" id="Page_115">[Pg 115]</a></span></p>
+<p class="center">CASES OF RECESSIVENESS IN MAN</p>
+
+<p><b>Recessive Conditions More Difficult to Deal With Because They Are
+Frequently Masked.&mdash;</b>Coming now to the question of recessive conditions in
+man, we find that defects are more likely to be of recessive than of
+dominant type. Apparently normality usually means the presence of normal
+determiners and abnormality, the absence of some essential determiner. In
+the latter case, a unit-factor has seemingly been lost out in some way in
+the germ-plasm, and the product of such germ-plasm is therefore
+incomplete. As long as the loss is counterbalanced by the presence of a
+single determiner from the other line of ancestry, that is, as long as the
+simplex (Aa) condition prevails, the loss may not be in evidence, except
+in cases of incomplete dominance (taints, etc.), but any mating which
+permits of the production of the nulliplex condition will bring the defect
+to expression again.</p>
+
+<p>&nbsp;<span class="pagenum"><a name="Page_116" id="Page_116">[Pg 116]</a></span></p>
+<div class="figcenter"><img src="images/img27.jpg" alt="" /></div>
+<p class="center"><span class="smcap">Fig. 27</span></p>
+
+<p class="descrip">Chart showing inheritance of <i>Huntington&#8217;s chorea</i> in the R&mdash;&mdash; family
+(courtesy of Dr. W. F. Lorenz); 1, 2 have been patients at Mendota
+Hospital for the Insane; 3, died of &#8220;paralysis&#8221;; the fourth or last
+generation indicated by the cross, ranging in age from 6 to 14, are too
+young yet to show their condition as regards this malady.</p>
+<p>&nbsp;</p>
+
+<p>The obscure nature of recessives makes such conditions more difficult to
+deal with than dominant defects. For as regards the latter we have seen
+that marriage of unaffected members of the family as far as that
+particular trait is concerned, is perfectly safe, even to a cousin, for
+once the germ-plasm is purged of such a positive factor, it, in so far as
+we know, remains pure. But in the case of a recessive character due to the
+absence of some necessary determiner a normal offspring of simplex
+constitution (Aa) will probably transmit to half of his children the
+capacity for handing on the defect, or if mated to another normal
+individual of simplex constitution (Aa) is likely to have the actual
+defect revealed again in one-fourth of his children and latent in
+two-thirds of the remainder.</p>
+
+<p><b>Albinism a Recessive.&mdash;</b>As an easily understood illustration of this type
+of case we may take human albinism, a condition which is due to the
+absence of a pigment-developing determiner. According to Davenport the
+albinic condition is recessive to normal condition. If albino (aa) is
+mated with albino (aa) nothing but albino children may be expected. An
+albino (aa) mated with a normal individual will have normal<span class="pagenum"><a name="Page_117" id="Page_117">[Pg 117]</a></span> offspring
+(Aa), but they will have the capacity for transmitting albinism to their
+descendants. Thus the normal offspring (Aa) of an albino (aa) and a normal
+parent (AA) if mated to another normal individual (Aa) who has also had an
+albino parent will probably transmit actual albinism to one-fourth of his
+children and the same capacity that he himself has of producing albinos,
+to one-half of his children, although the latter will appear to the eye to
+be normal.</p>
+
+<p><b>Other Recessive Conditions in Man.&mdash;</b>If for albinism we substitute certain
+forms of insanity, hereditary feeble-mindedness (Fig. 28, <a href="#Page_118">p. 118</a>), or
+hereditary epilepsy, all of which apparently follow the same law, we can
+readily understand how unfit such matings are where both strains are
+affected. Marriage with similarly defective stock will result in the
+affection appearing in one-fourth of the progeny, and one-half of them,
+though apparently normal themselves, will have the capacity for
+transmitting the imperfection. It is in the existence of such hidden
+factors that the chief danger in the marriage of cousins, or in fact any
+consanguineous marriage lies.</p>
+
+<p>A few of the various defects which seem to be inherited as recessives when
+mated with normality are: susceptibility to cancer; <i>chorea</i> (St. Vitus&#8217;
+dance); true dwarfism (all parts proportionately reduced); <i>Alkaptonuria</i>
+(urine darkens after passage); alcoholism and criminality, where based on
+mental deficiency; hereditary <i>hysteria</i>; <i>multiple sclerosis</i> (diffuse
+degeneration of nervous tissue); <i>Friedreich&#8217;s disease</i> (degeneration of
+upper part of the spinal cord); <i>Merriere&#8217;s disease</i> (dizziness and
+roaring in ears); <span class="pagenum"><a name="Page_118" id="Page_118">[Pg 118]</a></span><i>Thomsen&#8217;s disease</i> (lack of muscular tone); hereditary
+<i>ataxia</i>; possibly the tendency to become hard of hearing with increased
+age; and possibly, non-resistance to tuberculosis.</p>
+
+<p>Of non-pathological conditions in man which are inherited as recessives,
+apparently either very great or very small intellectual ability are
+examples.</p>
+
+<p>&nbsp;</p>
+<div class="figcenter"><img src="images/img28.jpg" alt="" /></div>
+<p class="center"><span class="smcap">Fig. 28</span></p>
+
+<p class="descrip">Chart showing descent of feeble-mindedness as a typical recessive (after
+Goddard). Squares represent males, circles females; DD, homozygous
+dominant; DR, heterozygous dominant (i. e. normal although a carrier); RR,
+pure recessive; N, normal; F, feeble-minded; A, alcoholic.</p>
+<p>&nbsp;</p>
+
+<p><b>Breeding Out Defects.&mdash;</b>Even though recessive defects occur in a stock,
+there is the possibility of diluting out the imperfection in successive
+generations if care is taken always to marry into a stock wholly free from
+it. For example, a normal individual carrying a recessive defect will bear
+the abnormality in half of his or her germ-cells. This means that when
+such an individual marries a normal, non-carrier, half of their children
+will be wholly normal (AA) and half will be carriers; normal but of
+simplex constitution (Aa). If now this generation, <span class="pagenum"><a name="Page_119" id="Page_119">[Pg 119]</a></span>carriers and
+non-carriers, marry only into normal strains of duplex constitution, then
+their combined issue will be likewise normal with only one-fourth of them
+carriers of the imperfections. This means that even if all of this last
+generation were married to persons having the defect only one out of four
+would have children showing it although the remaining children would be
+carriers. On the other hand if mated to normals only one-eight of the next
+generation would be carriers. Thus by continually marrying into strong
+strains liability to manifest any recessive defect can be diminished in a
+few generations until the descendants are no more likely to have defective
+children than are members of our ordinary population.</p>
+
+<p>The proportion in which the recessive defect would appear in successive
+generations if all persons in a given generation married only normal
+individuals who were non-carriers is indicated in the following table
+where AA indicates a normal individual, Aa one who is normal but a
+carrier, and aa an individual with the imperfection expressed; to indicate
+proportions simply after the first generation, four is arbitrarily chosen
+as the number of children which results from each marriage:</p>
+
+<table border="0" cellpadding="0" cellspacing="0" summary="table">
+<tr><td>&nbsp;</td>
+    <td><span class="spacer">&nbsp;</span></td>
+    <td align="center">Matings</td>
+    <td>&nbsp;</td>
+    <td align="center">Children</td></tr>
+<tr><td>Generation 1</td>
+    <td>&nbsp;</td>
+    <td>aa &times; AA</td>
+    <td>&nbsp; == &nbsp;</td>
+    <td>&nbsp; Aa</td></tr>
+<tr><td>Generation 2</td>
+    <td>&nbsp;</td>
+    <td>Aa &times; AA</td>
+    <td>&nbsp; == &nbsp;</td>
+    <td>2AA + 2Aa</td></tr>
+<tr><td>Generation 3</td>
+    <td>&nbsp;</td>
+    <td>AA &times; AA</td>
+    <td>&nbsp; == &nbsp;</td>
+    <td>4AA</td></tr>
+<tr><td colspan="2">&nbsp;</td>
+    <td>AA &times; AA</td>
+    <td>&nbsp; == &nbsp;</td>
+    <td>4AA</td></tr>
+<tr><td colspan="2">&nbsp;</td>
+    <td>Aa &times; AA</td>
+    <td>&nbsp; == &nbsp;</td>
+    <td>2AA + 2Aa</td></tr>
+<tr><td colspan="2">&nbsp;</td>
+    <td>Aa &times; AA</td>
+    <td>&nbsp; == &nbsp;</td>
+    <td class="botbor">2AA + 2Aa</td></tr>
+<tr><td colspan="4">&nbsp;</td>
+    <td>12AA + 4Aa</td></tr></table>
+
+<p><span class="pagenum"><a name="Page_120" id="Page_120">[Pg 120]</a></span><b>Other Inheritable Conditions in Man.&mdash;</b>While many pedigrees show beyond
+dispute that such qualities as musical ability, literary ability, memory,
+calculating ability, mechanical skill, longevity, peculiarities of
+handwriting, obesity and muscular strength, for example, are inherited,
+their modes of inheritance have not yet been sufficiently analyzed to
+express them exactly.</p>
+
+
+
+<p>&nbsp;</p><p>&nbsp;</p>
+<hr style="width: 50%;" />
+<p><span class="pagenum"><a name="Page_121" id="Page_121">[Pg 121]</a></span></p>
+<h2><a name="CHAPTER_V" id="CHAPTER_V"></a>CHAPTER V</h2>
+<p class="title">ARE MODIFICATIONS ACQUIRED DIRECTLY BY THE BODY INHERITED?</p>
+
+
+<p><b>Which New Characters Are Inherited?&mdash;</b>Any new feature which appears in a
+given organism may have had its origin in some change which has come about
+in the germ from which it sprang, or it may be merely the product of some
+unusual stimulus operating on the body. While the outcome, as far as the
+present individual is concerned, is in each case a definite modification,
+the matter of inheritance is a very different question. On the first
+alternative where the new character is the outcome of germinal change, it
+is obvious that the altered germ-plasm will find expression in a similar
+way in succeeding generations as long as the new germinal combinations
+persist. On the other hand, if the new character has resulted merely from
+some influence operating on the body of the individual, then to be
+inherited it would also have in some way to be transferred to and
+incorporated in the germ-plasm. Inasmuch as the body or soma of any
+individual is highly plastic and since various of its ultimate features
+may be mere somatic modifications, it is important to decide if possible
+whether or not somatic variations which are not of germinal origin can be
+inherited.</p>
+
+<p><b>Examples of Somatic Modifications.&mdash;</b>For example, the small foot of the
+Chinese woman of certain caste is the result of inherent germinal factor
+for the<span class="pagenum"><a name="Page_122" id="Page_122">[Pg 122]</a></span> production of a foot plus the effects of binding which are in no
+wise germinal. The hand of the skilled pianist is a normal hand of
+germinal origin and normal environment plus the effects of special
+training. Again, the head of the Flathead Indian is a normal head of
+germinal origin and environment plus the effects of flattening. Similarly,
+almost any malformation of extrinsic origin may be cited, ranging from
+mutilations and amputations, scars and the like to monstrosities such as
+one-eyed fish which may be produced by subjecting a developing embryo to
+adverse conditions of development.</p>
+
+<p><b>Use and Disuse.&mdash;</b>Even reactions set up through the organism&#8217;s own
+activities must produce changes. For example, a muscle has a certain
+average of normal development in the average man; it comes to this through
+the innate nature of its component cells plus a certain average amount of
+exercise. It may, however, be developed far beyond this average by
+excessive exercise. On the other hand, it is a well-known fact that an
+unused organ weakens or may remain but partially developed. Thus either
+use or disuse may play an important part in the molding of a given
+individual. But whether or not in doing this it similarly affects the germ
+is a very different matter.</p>
+
+<p><b>The Problem Stated.&mdash;</b>The question is can such enhanced or suppressed
+development, or can new or modified characters, produced in an individual
+by external agencies be so reflected on the germ-cell of the individual
+that they tend to reappear <i>as such</i> in its offspring without requiring
+the same external factors for their production?</p>
+
+<p><span class="pagenum"><a name="Page_123" id="Page_123">[Pg 123]</a></span><b>Special Conditions Prevail in Mammals.&mdash;</b>Before proceeding further we must
+recognize clearly the very special conditions which exist in most mammals.
+With them environment is in part an intra-maternal environment and in part
+independent of parental influences. Thus the formula for most non-mammalia
+would be&mdash;</p>
+
+<div class="blockquot"><p>Individual == egg + non-parental environment; but</p></div>
+
+<p>for most mammals, including man&mdash;</p>
+
+<div class="blockquot"><p>Individual == egg + intra-maternal environment + non-parental
+environment.</p></div>
+
+<p>This condition in mammals introduces a complicating factor which is likely
+to obscure the whole issue unless we bear it constantly in mind. In other
+words, we must discriminate sharply, in the discussion of inheritance in
+man, for instance, between two classes of influences which may exist in
+the infant at birth, that is, which are <i>congenital</i>; namely, those which
+were truly inherent&mdash;were in the germ-cells&mdash;at the very inception of the
+young individual, and (2) those which might later have been derived from
+either parent by the yet unborn offspring. The latter are not regarded as
+truly hereditary. Since certain diseases or their effects belong here we
+occasionally find a physician using the term inheritance for such prenatal
+influences, but the more careful ones now employ the term <i>transmission</i>
+to discriminate between such conditions and true inheritance. In its
+biological usage inheritance always refers to germinal constitution and
+never to any condition that may be thrust on a developing organism before
+birth. It is clear, then, that congenital conditions are not all
+necessarily cases of inheritance.</p>
+
+<p><span class="pagenum"><a name="Page_124" id="Page_124">[Pg 124]</a></span><b>Three Fundamental Questions.&mdash;</b>To get at the question of the inheritance of
+body modifications with the least confusion, let us examine it in the form
+of three fundamental questions, as follows:</p>
+
+<p>1. Can external influences directly affect the germ-cells?</p>
+
+<p>2. Can external influences, operating through the intermediation of the
+parental body, affect the germ-cells? If so, is the effect a specific and
+a permanent one which persists in succeeding generations independently of
+external influences similar to those which originally produced it? Only
+such a condition as this would rank as the inheritance of a somatic
+modification.</p>
+
+<p>3. Can the appearance of new characters be explained on any other ground,
+or on any more inclusive basis, than through the transmission of somatic
+acquirements, or do organisms possess heritable characters which are
+inexplicable as inheritance of such modifications?</p>
+
+<p>Obviously the only way the question can be settled is through careful
+experimentation in which all possible sources of error have been foreseen
+and guarded against. Much experimental work has been undertaken for the
+solution of this problem as the goal and we may therefore select typical
+ones of these experiments and apply the results toward answering our three
+questions.</p>
+
+<p><b>External Influences May Directly Affect the Germ-Cells.&mdash;</b>There is evidence
+that under special conditions external influences may in certain organisms
+affect the germ-cells, but that this occurs <span class="pagenum"><a name="Page_125" id="Page_125">[Pg 125]</a></span>commonly is extremely
+doubtful. For example, Professor MacDougal, by treating the germ-cells of
+the evening primrose with various solutions, such as sugar, zinc sulphate
+and calcium nitrate, has apparently succeeded in producing definite
+germinal mutations. He injected the solution into the ovary of the flower
+the forenoon of the day at the close of which pollination would occur. He
+reports that in this way changes were produced in the germ which found
+expression in new and permanent characters.</p>
+
+<p>Professor Tower has experimented for a number of years with various
+species of <i>Leptinotarsa</i>, the potato beetle. By varying the conditions of
+temperature, humidity and atmospheric pressure when females were laying
+their eggs, he reports having produced variations in the young which came
+from these eggs although the mothers themselves were not changed.
+According to Professor Tower slight increase or decrease in these
+environmental factors stimulated the activity of the color producing
+ferments, giving rise to melanic or darker individuals. Greater increase
+or decrease, inhibited them and produced albinos. He found also that at
+times the same stimulus might show different results in different eggs.
+The effect, therefore, is a general and not a specific one. Ordinarily the
+eggs of these beetles are laid in batches. When one of these batches was
+laid and left under normal conditions, the usual form of young hatched
+from it, but other batches from the same female under abnormal conditions
+resulted in the production of atypical forms. For example, a normal
+two-brooded<span class="pagenum"><a name="Page_126" id="Page_126">[Pg 126]</a></span> form became five-brooded. The commonest modification was the
+production of various color types. These once established, according to
+Professor Tower, behave as independent, inheritable units.</p>
+
+<p>The experiments of Doctor Bardeen with X-rays and of others with X-rays,
+radium and other agents on the sperm and ova of amphibia show that these
+are very susceptible to injurious influence at or near the time of
+fertilization.</p>
+
+<p><b>Such Effects Improbable in Warm-Blooded Animals.&mdash;</b>However possible it may
+be to bring about germinal changes in invertebrata or lower vertebrata by
+such external agents as temperature and the like it is obvious that the
+probability of such extrinsic influences affecting the germ-cells of
+warm-blooded animals is very remote indeed. In the latter the germ-cells
+are more or less distant from the exterior and are at practically a
+constant temperature. Such experiments, therefore, beyond showing the
+possibility of producing changes in germ-cells, do not have very direct
+bearing on the problem of how inheritable variations are produced in man.
+In his case about the only avenue of approach through which germ-cells
+might be influenced is the blood or lymph.</p>
+
+<p><b>Poisons in the Blood May Affect the Germ-Cells.&mdash;</b>Any poisonous material in
+the latter might injuriously affect the gametes. We know, in fact, that
+such poisons as alcohol, lead and various drugs, and also the toxins of
+various diseases, do so affect germ-cells. It seems plausible to suppose
+that changing conditions of nutrition may affect the constitution of the
+<span class="pagenum"><a name="Page_127" id="Page_127">[Pg 127]</a></span>germ-cells and thus induce changes in the organism which arise from these
+cells, but such nutritional effect is not yet a matter of established
+fact.</p>
+
+<p><b>Difficulty of Explaining How Somatic Modifications Could be Registered in
+Germ-Cells.&mdash;</b>As to our second query concerning the possibility of
+affecting the germ-cells through the intermediation of parental tissues,
+it is evident at a glance that since the germ-cells are built up along
+with the body and are not a product of it (Fig. 2, <a href="#Page_13">p. 13</a>), if such effects
+are possible they must take place through the agency of some transporting
+medium. The germ-cells, being lineal descendants of the original fertile
+germ or zygote, already have the same possibilities of developing into an
+adult that the zygote had, and so the problem becomes one of modifying a
+complete germ already organized rather than of establishing a new germ by
+getting together samples of every part of the body. This is all the more
+evident when one realizes that usually the germ-cells are set apart long
+before the body becomes adult, that is, before the body has developed most
+of its characteristics. Moreover, among lower animals many instances are
+known where the immature young or even larv&aelig; will produce offspring which
+nevertheless ultimately manifest all the structures of the adult
+condition.</p>
+
+<p>But supposing specific modifications of the germinal mechanism were
+possible, it is difficult to comprehend how an influence at a distant
+point of the body could reach the germ-cell, to say nothing of the even
+greater difficulty of understanding how it could become registered in the
+germ in a specific way as affecting a <span class="pagenum"><a name="Page_128" id="Page_128">[Pg 128]</a></span>particular part. For it must be
+remembered that the organs of the adult do not exist as such in the germ
+but are present there only as potentialities. How, for example, can a
+change in the biceps muscle of one&#8217;s arm be registered in a germ-cell in
+which there is no biceps muscle, but merely the possibilities of
+developing one? Or how can increased mental ability which is contingent on
+the elaboration of certain brain-cells be impressed on a germ which has no
+brain-cells but only the capacity under certain conditions of producing
+such cells? For the brain of a child is not descended from the brain of
+his parent, but from a germ-cell carried by that parent.</p>
+
+<p><b>Persistence of Mendelian Factors Argues Against Such a Mode of
+Inheritance.&mdash;</b>On the face of things, the apparent inviolability of
+Mendelian factors which may remain unexpressed in the germ for one or many
+generations&mdash;indeed the whole matter of genotypical differences in the
+gametes of the same individual&mdash;shows the improbability of somatic
+interference with the germ-plasm. But notwithstanding this, because of the
+great importance of the issue, it is well to review in some considerable
+detail the various phases and possibilities of the question.</p>
+
+<p><b>Experiments on Insects.&mdash;</b>Some of the attempts to secure evidence of the
+transmission of personally acquired parental modifications in insects are
+very interesting. Many insects in the larval stages, particularly just
+after pupation seem to be especially susceptible to external influences.
+They have been much used, therefore, for purposes of experiment. It has
+long been known that differences in size, in color and<span class="pagenum"><a name="Page_129" id="Page_129">[Pg 129]</a></span> even in the shape
+of wings can be produced by various agents if applied at this period of
+development. From the standpoint of heredity, however, the important
+consideration is to determine if these experimentally induced changes have
+been reflected on to the germ-cells so that they reappear in the offspring
+of the modified individuals.</p>
+
+<p>It has been found that in some cases where male and female are of
+different color, the color of the female can be changed to that of the
+male by altering the conditions of temperature. In certain cases types can
+be changed by cold so that they resemble varieties of the same species
+found farther north, and by heat, varieties found farther south. But not
+all individuals of a given lot are affected, and often different
+individuals of the same kind show different effects. Moreover, in some
+cases the same aberrations were produced by heat as by cold. This
+indicates that it is not so much a question of specific effects as a
+general physiological change, apparently mainly a matter of direct
+influence of temperature on the chemical composition of the pigments. The
+Countess von Linden in fact has shown that the extracted pigments can be
+made to undergo the same changes of color in a test-tube by heat and cold
+as in the pup&aelig;. But there is no evidence that the germ-cells of the living
+insect were affected in a specific way. In a small fraction of the
+offspring of such modified individuals abnormalities appeared, but these
+were not always of the same kind as those which had been produced in the
+parent. That is, there was no evidence of a trait or character having been
+acquired by the body and handed<span class="pagenum"><a name="Page_130" id="Page_130">[Pg 130]</a></span> on to the germ-cell. Where an effect was
+produced on the germ-cell it was probably produced directly as in the
+first cases discussed.</p>
+
+<p>Size, colors and markings of butterflies have also been altered by
+subjecting the caterpillars or the pup&aelig; to such influences as strong
+light, electricity, various chemical substances, centrifuging, diminished
+oxygen supply, etc., but the results were in the main confined to the
+immediate generations. In the few cases where permanent inheritable
+changes were seemingly produced they were more reasonably interpreted as
+the effects of direct action on the germ-cells than as examples of
+inherited somatic modifications.</p>
+
+<p>Starvation experiments which resulted in the dwarfing of adult individuals
+have been performed on various insects, and while the dwarf condition may
+persist through one or two generations due to a diminished food supply in
+the eggs of the dwarf, the stock in question when returned to normal food
+conditions soon resumes its original characteristic size.</p>
+
+<p><b>Experiments on Plants.&mdash;</b>Many experiments have been performed with plants,
+inasmuch as they are particularly prone to become modified by changes of
+food supply, or climate. For example, plants which grow luxuriantly in a
+warm moist climate or a rich soil may become stunted and markedly changed
+if transplanted to a cold climate or a poor soil. Naturally, their progeny
+will exhibit the same behavior as long as they are kept under the new
+conditions. Experiments carried on through numerous generations, however,
+practically all show that the germinal constitution of the plants remains
+unchanged, for when their seeds are<span class="pagenum"><a name="Page_131" id="Page_131">[Pg 131]</a></span> planted under the original favorable
+conditions of soil or climate, the plants resume their former habits of
+growth. Naegeli, for instance, who made a study of many varieties of
+Alpine plants, and who carried on experiments with many of them for years
+in the Garden of Munich, concluded that no permanent effects had been
+produced by the Alpine climate and conditions in plants from other regions
+which had come under its influence. A few botanists have claimed to have
+found that the changes produced by the Alpine climate have persisted for a
+generation or two and have then worn off. More recent experiments on
+various of our field grains which have been stunted and cut down in
+productivity by growing for a number of generations under adverse
+conditions show that they have not been permanently modified by such
+treatment, for they resume normal productivity and size when grown again
+under favorable conditions.</p>
+
+<p>On the other hand, Lederbaur found that a common weed, <i>Capsella</i>, when
+transplanted from an Alpine habitat to the lowlands did not return to the
+lowland type of the weed, but retained certain of its Alpine
+characteristics. It is not clear, however, that this particular species
+during its long sojourn of many generations in Alpine conditions may not
+have undergone a series of germinal variations and have developed into a
+new variety or species quite independently of changes wrought in the germ
+by reflected somatic effects. Indeed, in face of the preponderance of
+other cases to the contrary, this interpretation would seem to be the more
+plausible one.</p>
+
+<p><span class="pagenum"><a name="Page_132" id="Page_132">[Pg 132]</a></span><b>Experiments on Vertebrates.&mdash;</b>In the vertebrates we may also find examples
+of various somatic modifications experimentally produced, but evidence of
+their inheritance is as difficult to establish as in the invertebrates.
+Let us examine a few of the more significant of these which are alleged by
+some to bear evidence of such inheritance.</p>
+
+<p>By decreasing the amount of water in an aquarium Marie von Chauvin was
+able to transform the aquatic, gill-breathing salamander <i>Axolotl</i> into
+the gill-less land form <i>Ambystoma</i>, heretofore regarded by systematists
+as a different species. Either of these forms when sexually mature
+produces its like. The salamanders in question have both lungs and gills,
+but after a time the ones which are to be land forms lose their gills and
+become exclusively lung-breathers. What seems to have been accomplished
+then is the accelerating or forcing of normal natural tendencies already
+inherent in the organism instead of introducing something new into the
+inheritance by way of the soma. <i>Axolotl</i> is in all probability merely a
+larval form of <i>Ambystoma</i> which with high temperature and an abundance of
+water reproduces without advancing to the final possible stage of its life
+cycle.</p>
+
+<p><b>Epilepsy in Guinea-Pigs.&mdash;</b>Perhaps the most frequently cited case and the
+one in which the defenders of the idea of somatic inheritance usually take
+final refuge is that of Doctor Brown-Sequard&#8217;s guinea-pigs,
+notwithstanding the fact that no one has had convincing success in
+repeating the experiments and that the original results are apparently
+open to more than one interpretation. This experimenter rendered
+guinea-pigs<span class="pagenum"><a name="Page_133" id="Page_133">[Pg 133]</a></span> epileptic by certain injuries to the nervous system. Epilepsy
+appeared in some of the offspring of these operated animals. He regarded
+this as an example of the inheritance of an artificially induced epilepsy.
+An indirect loss of toes occurred in some of the parents as a result of
+the operations on the nervous system. Some of their young also had missing
+toes. However, as has been pointed out by various critics, guinea-pigs are
+strongly predisposed toward epileptic-like seizures, and the epilepsy in
+the young may have been merely a coincidence. Voison and Peron believe
+they have shown that in epilepsy a toxin is produced that may affect the
+unborn fetus. That is, the result might have been due to a poison derived
+directly from the mother. The experiments in fact show that it was mainly
+in the offspring of affected mothers that the condition appeared. Others
+maintain that we do not know the exact nature of epilepsy, that in some
+cases it may be the result of infection by disease-germs, and that
+Brown-Sequard&#8217;s cases may, therefore, have been merely the communication
+of a disease from parent to child. As to the disappearance of toes it is a
+well-known fact that rodents in particular are likely to gnaw off the toes
+of their young very soon after birth, and little credence can be put in a
+lack of toes in such young as cases of inheritance except under conditions
+of much more careful observation than existed in Brown-Sequard&#8217;s
+experiments. A fuller account of these experiments will be found in
+Romanes&#8217; <i>Darwin and After Darwin</i>, Vol. II, Chap. 6.</p>
+
+<p><b>Effects of Mutilations Not Inherited.&mdash;</b>Many experiments have been
+performed by investigators to <span class="pagenum"><a name="Page_134" id="Page_134">[Pg 134]</a></span>determine whether or not the results of
+mutilation are transferred to succeeding generations, but so far only with
+negative results. Many such experiments have been unwittingly carried on
+for many generations, in fact, by breeders and fanciers, in the docking of
+horses, dogs and sheep, the dehorning of cattle and the like, yet no
+satisfactory evidence of the transmission of such conditions in any degree
+has ever been forthcoming. The mutilations or distortions of the human
+body through various rites or social customs also fails to yield any
+convincing examples. Foot-binding, head-binding, or waist-binding must be
+repeated in each successive generation to produce the particular type of
+&#8220;beauty&#8221; that results from such deformities. And lucky it is for man that
+injuries do not persist in subsequent generations, otherwise the modern
+human being would be but a maimed relic of past misfortunes.</p>
+
+<p><b>Transplantation of Gonads.&mdash;</b>An interesting experimental test regarding the
+effect of the body on the germ was made recently by Castle and Phillips
+with guinea-pigs. It will be recalled from the discussion on Mendelism
+that when a black guinea-pig is mated with a white one the offspring are
+always black. These experimenters transplanted the ovaries from a young
+black guinea-pig to a young white female whose own ovaries had been
+previously removed. This white female was later mated to a white male.
+Although she produced three different litters of young, six individuals in
+all, the latter were all black. That is, not a trace of coat-color of the
+white father or of the white foster-mother was impressed on the
+transplanted germ-cells or the developing young. Later<span class="pagenum"><a name="Page_135" id="Page_135">[Pg 135]</a></span> experiments of the
+same kind by Castle and Phillips, with other varieties of guinea-pigs,
+have yielded the same results. The body of the mother, indeed, seems to
+serve merely as a protective envelope and a source of nutrition.</p>
+
+<p><b>Effects of Body on Germ-Cells General, Not Specific.&mdash;</b>As far as the
+evidence regarding the modification of the germ-plasm by the body is
+concerned, we must conclude then that while under special circumstances
+the germ-cells may be affected, the effect is general rather than specific
+and the result as seen in the offspring has no discoverable correlation
+with any particular part or structure of the parental soma. The effect is
+presumably of much the same nature as where the germ is directly affected
+by external agents. Where a new character or a modification of one already
+existing is produced by a given condition of environment, in our
+experience so far to have the same repeated in the offspring, a similar
+evocative condition must prevail in the environment of the latter. Or in
+other words the new character is not a permanent one which persists in
+succeeding generations independently of external influences similar to
+those which originally produced it.</p>
+
+<p><b>Certain Characters Inexplicable as Inherited Somatic Acquirements.&mdash;</b>It
+would require remarkable credulity, in fact, to believe that some of the
+most striking features about certain plants or animals could have been
+developed by means of the inheritance of somatic modifications. For
+example, many animals such as the quail, the rabbit, or the leaf-butterfly
+are protectively colored. That is, they harmonize in <span class="pagenum"><a name="Page_136" id="Page_136">[Pg 136]</a></span>color-pattern with
+their surroundings so closely that they are overlooked by their enemies.
+But how can this oversight on the part of an enemy so affect the bodies
+and through them the germ-cells of such individuals as to develop so high
+a degree of protective coloration? Or how, indeed, could any of numerous
+adaptive structures which one can think of, such as the color or scent of
+flowers to lure insects for cross-pollenation, the various grappling
+devices on many seeds to secure wide distribution by animals, or the like,
+have been directly produced by use or disuse or by any variation produced
+in them by the agents to which they are adapted?</p>
+
+<p><b>The Case of Neuter Insects.&mdash;</b>A very instructive example of the
+improbability that great skill, highly specialized structures, or certain
+instincts are first developed in the parental body as the result of use
+and then passed on to the offspring, is seen in the case of neuter
+insects. In bees, for example, there are three classes of individuals: the
+drones or males; the queens or functional females; and the workers, which
+are neuter, that is, take no part in reproduction. The latter are really
+sexually undeveloped females. The queen can lay either fertilized or
+unfertilized eggs. The latter always give rise to males. The workers
+gather the food, attend the queen, wait on the young, construct the comb,
+and in short perform all the ordinary functions of the colony except the
+reproductive. They have many highly specialized structures on various
+parts of their bodies for carrying on their many activities, as well as
+the very highly specialized instincts necessary to the maintenance of the
+colony.<span class="pagenum"><a name="Page_137" id="Page_137">[Pg 137]</a></span> But now, complex and highly developed as these workers are, since
+they do not give rise to offspring, no matter how much experience or
+structural modifications they may acquire during their lifetime, it can
+not be handed on to another generation. Nor can they have come to their
+present highly organized state through such a form of transmission since
+they are not the descendants of workers but of a queen. Any new
+modifications that appear in the workers of a colony must therefore have
+their origin in changes which have taken place in the germ-cells of the
+queen, and not in the soma of some other worker. It has been argued that
+the worker has not always been infertile; that at a more primitive stage
+of the evolution of the bee colony every female was both worker and
+mother, and that individual somatic acquirements might therefore have been
+transmitted, but this argument can not hold for many of the instincts or
+features of the modern bee because these have to do only with the
+conditions of life which exist in the colony in its present form. It is
+obviously absurd to maintain, for instance, that all the highly
+specialized instincts incident to queen production, queen attendance and
+the like were functionally produced through usage before there was any
+queen to produce or attend, while on the other hand, the very necessity of
+queen production and maintenance is the outcome of the infertility of the
+workers. Some workers have been known to lay eggs, but as these are few in
+number and are never fertilized, which means if they develop they can only
+produce males, they can play no considerable part in inheritance.</p>
+
+
+<p>&nbsp;<span class="pagenum"><a name="Page_138" id="Page_138">[Pg 138]</a></span></p>
+<p class="center">ORIGIN OF NEW CHARACTERS</p>
+
+<p><b>Origin of New Characters in Germinal Variation.&mdash;</b>This brings us to our
+last query as to whether the appearance of new characters can be explained
+on any other or any more inclusive ground than that which infers that
+changes undergone by the parent-body are in some way registered in the
+germ-cells so as to be repeated in a certain measure in the body of the
+offspring. The answer to the question of how inheritable variations do
+come to appear in offspring if not through changes produced in the body of
+the parent, is uncertain; nevertheless most biologists believe that they
+do not have such a somatic origin but arise directly as germinal
+variations. Some would attribute them to the fluctuating nature of living
+substance in general. The instability of protoplasm is one of its striking
+characteristics. It is constantly being broken down and built up, or, in
+other words, undergoing waste and repair. Like all other protoplasm, that
+of the germ-cells must also undergo these metabolic changes and it is
+possible though not proved that in this give and take of substances small
+changes occur in their constitution which find expression in the offspring
+as variations. As already seen, substances in the blood other than food
+may also affect the constitution of the germ-cells.</p>
+
+<p><b>Sexual Reproduction in Relation to New Characters.&mdash;</b>Some biologists
+attribute great importance to sexual reproduction as a basis of variation
+and the origin of new characters. They argue that the mingling of
+determiners from two different lines must<span class="pagenum"><a name="Page_139" id="Page_139">[Pg 139]</a></span> produce many new combinations
+and expressions of germinal potentialities. Plausible as the argument
+seems at first sight no one has succeeded as yet in securing proof that
+absolutely new characters can be originated in this way. What seems to
+occur under such circumstances is merely a reshuffling or sorting of old
+unit-characters. Although innumerable permutations and combinations of
+these may be made which find new expression outwardly, this is obviously
+not creating determiners of new unit-characters in the germ-plasm. While
+many biologists would not deny the possibility or even the probability
+that the determiners of unit-characters may sometimes combine or influence
+one another so as to form actual permanent new characters, the proof of
+such performance is wholly lacking. On the other hand, there are not a few
+biologists who argue that sexual reproduction accomplishes just the
+reverse of increasing the extent of variation or creating new characters;
+according to them it tends to annul exceptional peculiarities of either
+parent by throwing the offspring back to the average racial type. It is
+thus looked on by these advocates as a stabilizer which reduces the
+amplitude of variations instead of increasing them. As a matter of fact
+the two ideas are not mutually exclusive; sexual reproduction may
+accomplish both of these ends. A limited number of observations and
+experiments have been made to test out the correlation between sexual
+reproduction and variation, but they have so far been too few or too
+inconclusive to enable us to come to a satisfactory conclusion.</p>
+
+<p>While we are uncertain about the method of origin<span class="pagenum"><a name="Page_140" id="Page_140">[Pg 140]</a></span> of new characters the
+fact remains that they do arise in abundance as abrupt mutations or
+otherwise and become a part of the permanent heritage of a stock. It is
+clear that sexual reproduction may be one important means by which a given
+new character which has arisen in one or a few individuals may become
+incorporated in the species at large. Through Mendelian combinations and
+segregations it would by cross-breeding be spread and gradually introduced
+into more and more strains of the general population.</p>
+
+<p><b>Why So Many Features of an Organism Are Characterized by
+Utility.&mdash;</b>Germinal variations are seemingly at first more or less hit or
+miss affairs as far as utility to the organism is concerned. Useless
+variations, so long as they are not actually harmful, may persist and
+apparently be indefinitely inherited. However, a special premium is put on
+variations which happen to be useful for they help the organism to succeed
+in its struggle for life and since success in the world of life means not
+only mere individual survival but also the production of progeny, through
+this very means insured transmission to subsequent generations. It is
+probable that the very many useful features of any organism, that is, its
+<i>adaptations</i>, have thus been established. It is possible also that many
+variations which at their inception are indifferent may wax in strength in
+successive generations until they reach a point where they must become
+either useful or harmful. In the former case they would mean increased
+insurance of survival for their possessors, in the latter, elimination.
+With such an automatic process as this operative in nature it is not
+astonishing that<span class="pagenum"><a name="Page_141" id="Page_141">[Pg 141]</a></span> the main features of any organism are characterized by
+their utility to it.</p>
+
+<p><b>Germinal Variation a Simpler and More Inclusive Explanation.&mdash;</b>The gist of
+the whole matter regarding the source of new characters in offspring seems
+to be that the explanation based on the idea of germinal variation is in
+last analysis the simpler and more inclusive, and there is no alleged case
+of inheritance of parental modification, which can not be equally well
+explained as the result of a germinal variation. There are numerous cases
+which can not be explained as transmissions of somatic acquirements even
+if this transmission could be established in certain cases. So, many
+biologists argue, why have two explanations when one is sufficient,
+especially when the other has never been conclusively established as true
+in any case and is obviously untrue in certain test cases? The attitude of
+most investigators is that of the open mind. While feeling that the weight
+of probability is very decidedly against the theory of the inheritance of
+somatic modifications, they still stand ready and willing to accept any
+evidence in its favor which when weighed in the balance is not found
+wanting.</p>
+
+
+<p>&nbsp;</p>
+<p class="center">ANALYSIS OF CASES</p>
+
+<p>While space will not permit extended discussion, in order further to fix
+the nature of the problem in mind as well as to exemplify the conditions
+that must be satisfied to form convincing evidence of inherited somatic
+acquirements, it will be well perhaps to analyze a few typical cases as
+they are frequently cited.</p>
+
+<p><span class="pagenum"><a name="Page_142" id="Page_142">[Pg 142]</a></span><b>Are the Effects of Training Inherited?&mdash;</b>Breeders and trainers very
+commonly believe that the offspring of trained animals inherit in some
+measure the effects of the training. Thus the increased speed of the
+American trotting horse is often pointed to as strong evidence of such
+transmission. According to W. H. Brewer, the earliest authentic record of
+a mile in three minutes was made in 1818. The improvement, approximately
+by decades, from that time was as follows:</p>
+
+<table border="0" cellpadding="0" cellspacing="5" summary="table">
+<tr><td>During</td>
+    <td>1st</td>
+    <td>decade</td>
+    <td>after</td>
+    <td>1818,</td>
+    <td>improved</td>
+    <td>to</td>
+    <td>2:34</td></tr>
+<tr><td>&nbsp;</td>
+    <td>2nd</td>
+    <td align="center">"</td>
+    <td align="center">"</td>
+    <td align="center">"</td>
+    <td align="center">"</td>
+    <td align="center">"</td>
+    <td>2:31&#189;</td></tr>
+<tr><td>&nbsp;</td>
+    <td>3rd</td>
+    <td align="center">"</td>
+    <td align="center">"</td>
+    <td align="center">"</td>
+    <td align="center">"</td>
+    <td align="center">"</td>
+    <td>2:29&#189;</td></tr>
+<tr><td>&nbsp;</td>
+    <td>4th</td>
+    <td align="center">"</td>
+    <td align="center">"</td>
+    <td align="center">"</td>
+    <td align="center">"</td>
+    <td align="center">"</td>
+    <td>2:24&#189;</td></tr>
+<tr><td>&nbsp;</td>
+    <td>5th</td>
+    <td align="center">"</td>
+    <td align="center">"</td>
+    <td align="center">"</td>
+    <td align="center">"</td>
+    <td align="center">"</td>
+    <td>2:17&#189;</td></tr>
+<tr><td>&nbsp;</td>
+    <td>6th</td>
+    <td align="center">"</td>
+    <td align="center">"</td>
+    <td align="center">"</td>
+    <td align="center">"</td>
+    <td align="center">"</td>
+    <td>2:13&#189;</td></tr>
+<tr><td>&nbsp;</td>
+    <td>7th</td>
+    <td align="center">"</td>
+    <td align="center">"</td>
+    <td align="center">"</td>
+    <td align="center">"</td>
+    <td align="center">"</td>
+    <td>2:08&#189;</td></tr></table>
+
+<p>By 1892, the date of Professor Brewer&#8217;s publications (See <i>Agricultural
+Science</i>, Vol. 4, 1892) the record had reached 2:08&#189;. Since then it has
+been lowered still further.</p>
+
+<p>On the face of it this looks like a good case of inheritance of training,
+and Brewer himself believed it such. If so this would mean that colts of a
+highly trained trotter would be faster than they would have been if their
+parent had remained untrained. It is impossible to get positive proof in
+the case of any trained horse since there is no way of establishing just
+how speedy the progeny would have been had the parent remained untrained.
+If it could be shown that colts sired by a trotter late in life were on
+the whole faster than those sired by the same father when younger and as
+yet not highly exercised in trotting,<span class="pagenum"><a name="Page_143" id="Page_143">[Pg 143]</a></span> then the facts might give some
+evidence of value, but unfortunately no such records are available.</p>
+
+<p>On the other hand, even ignoring the fact that improvement in track and
+sulky are probably the biggest items in the shortening of records in
+recent times, <i>selection</i> instead of inheritance of the effects of
+training will equally well account for any innate progress in trotting.
+And since, as pointed out by Professor Ritter, there are even more
+striking cases of similar improvements in other fields, such as college
+athletics, where the factor of use-inheritance is entirely precluded, it
+is wholly unnecessary to postulate it in the case of the trotter.</p>
+
+<p>For example an inspection of the records of college athletics for the last
+thirty-five years in running, hurdling, pole-vaulting, jumping, putting
+the shot, etc., shows on the whole a steady advance year by year.
+Moreover, the greatest improvement has occurred in those events in which
+skill and practise count for most together with selection of the
+inherently ablest candidate for the events. But in the case of athletics
+the improvements shown in thirty-five years have all come within a single
+generation and hence the inheritance of the effects of training is ruled
+out as a factor. Selection and improved training are the only factors
+operative.</p>
+
+<p>In the case of the trotter inheritance undoubtedly has also been a factor,
+but inheritance based on selection of what the race-track has shown to be
+the speediest individual, not inheritance of the effects of training. In
+other words, horses which have shown the capacity for being trained to the
+highest degree of<span class="pagenum"><a name="Page_144" id="Page_144">[Pg 144]</a></span> speed have naturally been selected as sires and dams
+and so through selection generation after generation a speedier strain has
+gradually been established.</p>
+
+<p><b>Instincts.&mdash;</b>When we turn to the realm of mental traits, particularly of
+instincts, we meet with a whole host of activities which are frequently
+pointed to by transmissionists as examples of inherited acquirements. Thus
+according to them, habits at first acquired through special effort
+ultimately become instinctive, or according to some, instinct is &#8220;lapsed
+intelligence.&#8221; Instances often cited are the pointing of the bird-dog, the
+extraordinary crop-inflation of the pouter-pigeon, or the tumbling of the
+tumbler pigeon. We can not stop to discuss these cases beyond pointing out
+as many others have done that practically all dogs have more or less of an
+impulse to halt suddenly, crouch slightly and lift up one fore-foot when
+they scent danger or prey, that all pigeons pout more or less, and that
+practically all show more or less instincts of tumbling when pursued by a
+hawk. Thus in all of these cases the fundamental germinal tendency is
+already at hand for the fancier to base his choice on and thus through
+selection build up the type desired. Just as in the fan-tailed pigeon, by
+repeatedly selecting for breeding purposes individuals which showed an
+unusual number of tail-feathers he has built up a type with an upright,
+fan-like tail having many more feathers than the twelve found in the tail
+of the ordinary pigeon, so by similar procedure in the case of other forms
+he has markedly enhanced certain features. The idea of instincts being
+&#8220;lapsed intelligence&#8221; is so clearly and concisely criticized in an<span class="pagenum"><a name="Page_145" id="Page_145">[Pg 145]</a></span>
+article by the late Professor Whitman<a name='fna_4' id='fna_4' href='#f_4'><small>[4]</small></a> that I can not do better than
+quote an excerpt. His views to the contrary are as follows:</p>
+
+<div class="blockquot"><p>&#8220;The view here taken places the primary roots of instinct in the
+constitutional activities of protoplasm and regards instinct in every
+stage of its evolution as action depending essentially upon
+organization. It places instinct before intelligence in order of
+development, and is thus in accord with the broad facts of the present
+distribution and relations of instinct and intelligence, instinct
+becoming more general as we descend the scale, while intelligence
+emerges to view more and more as we ascend to the higher orders of
+animal life. It relieves us of the great inconsistencies involved in
+the theory of instinct as &#8220;lapsed intelligence.&#8221; Instincts are
+universal among animals, and that can not be said of intelligence. It
+ill accords with any theory of evolution, or with known facts, to make
+instinct depend upon intelligence for its origin; for if that were so,
+we should expect to find the lowest animals free from instinct and
+possessed of pure intelligence. In the higher forms we should expect
+to see intelligence lapsing more and more into pure instinct. As a
+matter of fact, we see nothing of the kind. The lowest forms act by
+instinct so exclusively that we fail to get decided evidence of
+intelligence. In higher forms not a single case of intelligence
+lapsing into instinct is known. In forms that give indubitable
+evidence of intelligence we do not see conscious reflection
+crystallizing into instinct, but we do find instinct coming more and
+more under the sway of intelligence. In the human race instinctive
+actions characterize the life of the savage, while they fall more and
+more into the background in the more intellectual races.&#8221;</p></div>
+
+<p><span class="pagenum"><a name="Page_146" id="Page_146">[Pg 146]</a></span>For further discussion of this field the reader is referred to an
+excellent chapter on &#8220;Are Acquired Habits Inherited?&#8221; in C. Lloyd Morgan&#8217;s
+book, <i>Habit and Instinct</i>.</p>
+
+<p><b>Disease.&mdash;</b>Perhaps in the realm of disease more than in any other has an
+interest in the inheritance of somatic acquirements been manifested. The
+problem arising here is not essentially different from other questions of
+inheritance but since it is a matter of such practical importance to man,
+we may well give it special attention. We have to deal simply with the old
+questions of what is constitutionally in the germ, what is acquired by the
+body, and lastly, whether the somatically acquired is inherited. While we
+all know in a general way what is meant by disease, especially if some
+specific disorder such as scarlet fever, malaria or tuberculosis is
+mentioned, an attempt to give an accurate definition is much like trying
+to define a weed, inasmuch as what is functionally all right at one time
+or place may be all wrong at another, or what is normal in one animal may
+be abnormal in another. In general we may say that disease is derangement
+or failure of physiological function.</p>
+
+<p><b>Reappearance of a Disorder in Successive Generations Not Necessarily
+Inheritance.&mdash;</b>In attempting to study the inheritance of diseases we must
+recognize clearly at the outset that reappearance of a disease in
+successive generations by no means necessarily signifies inheritance.
+Before it can be pronounced such we must make sure that it is not a case
+of reimpressing similar modifications on the individuals of successive
+generations. For example, in England there<span class="pagenum"><a name="Page_147" id="Page_147">[Pg 147]</a></span> is a well-recognized condition
+known as collier&#8217;s lung which results from constant working in coal mines.
+And while both father and son may exhibit it, because of their similar
+
+occupations, there is nothing hereditary about the malady. Likewise there
+is what is known as emery grinder&#8217;s lung, and practically every large
+manufacturing city with soot-laden atmosphere leaves its impress on the
+lungs of the inhabitants. This will occur, of course, generation after
+generation, as long as such pollutions of the atmosphere continue to
+exist. It is clear that any unhealthy occupation is likely to cause the
+reappearance of an associated typical disease generation after generation
+as long as the children follow the calling of their parents. The common
+misconception that deformities or postures associated with a trade, such
+as a shoemaker&#8217;s or tailor&#8217;s, is genetically stamped on offspring by the
+end of the third or fourth generation results from failure to discriminate
+between real inheritance and mere reappearances under similar conditions
+of environment.</p>
+
+<p><b>Prenatal Infection Not Inheritance.&mdash;</b>Again, we must recognize that
+prenatal infection is not inheritance. We have already seen that the young
+mammal undergoes a certain period of intra-maternal development, but
+influences operating on it during this period of gestation must be
+reckoned with as environmental, not germinal. For example, it is said that
+an unborn child may take smallpox from its mother but this and all similar
+occurrences are cases of contagion. We find the great pathologist,
+Virchow, who with many others of his time was a believer in the
+inheritance of acquired characters, saying nevertheless <span class="pagenum"><a name="Page_148" id="Page_148">[Pg 148]</a></span>regarding such
+instances that, &#8220;What operates on the germ after the fusion of the
+sex-nuclei, modifying the embryo, or even inducing an actual deviation in
+the development, can not be spoken of as inherited. It belongs to the
+category of early acquired deviations which are therefore frequently
+congenital.&#8221;</p>
+
+<p><b>Inheritance of a Predisposition Not Inheritance of a Disease.&mdash;</b>We must
+discriminate sharply also between the inheritance of a predisposition and
+the inheritance of a disease itself.</p>
+
+<p>We often hear the statement made that tuberculosis is inherited and have
+cited in evidence certain consumptive families or strains. But
+tuberculosis is a bacterial disease and children of tuberculous parents
+are never born with the disease except in the rarest of instances.</p>
+
+<p><b>Tuberculosis.&mdash;</b>What is really inherited is a constitutional susceptibility
+to this particular germ. While almost any individual may contract
+tuberculosis when in a state of depressed vitality, or under stress of
+adverse surroundings, there is no doubt that certain families are more
+easily infected than others and much less resistant to the ravages of the
+disease when once it gains a foothold. However, a predisposition is a
+vastly different thing from the inheritance of the actual disease. For
+just as we are born with a nose well adapted to eye-glasses but not with
+eye-glasses on our nose, so many of us are born tuberculizable though not
+tuberculous, and every sanitary advance we make toward lessening the
+chances of infection is just so much more insurance for the susceptible.</p>
+
+<p>The whole problem of tuberculosis is an extremely<span class="pagenum"><a name="Page_149" id="Page_149">[Pg 149]</a></span> complex one. We do not
+know just the measure of the inheritance of the predisposition. Some
+writers in the past have maintained that tuberculosis is mainly a question
+of infection and not of inherent susceptibility, but steadily increasing
+evidence all points the other way.</p>
+
+<p>Where the predisposition exists the chances of infection are still, even
+under the conditions of present-day sanitation, very great. The close
+association between a consumptive and other members of the family through
+a prolonged period of time, of course, renders the latter likely to
+infection unless unusual care is exercised. Very often where a parent is
+consumptive a child contracts the malady shortly after birth and is
+
+particularly likely to do so if the mother, who nurses it and cares for it
+most intimately, is the tubercular member of the family. Where the mother
+is tubercular, indeed, the probabilities are that the child has already
+before birth had its vitality lowered through the toxins circulating in
+her blood or through defective nutrition, and in consequence does not
+resist well any diseases.</p>
+
+<p>Undoubtedly a large proportion of our infant mortality is of tubercular
+origin. It is now a well-established fact that much tuberculosis in
+children is attributable to drinking milk from tuberculous cows, yet we
+find individuals so uninformed and dairymen so mercenary that they fight
+all attempts of the commonwealth to test out cattle for tuberculosis so as
+to condemn the infected individuals and thus save our babies. Recent
+investigations made in some of our large pork-packing establishments also
+indicate that<span class="pagenum"><a name="Page_150" id="Page_150">[Pg 150]</a></span> hogs, especially such as have been around tubercular
+cattle, are often shot through and through with tuberculosis and that such
+flesh when used as food, if not thoroughly cooked, may become a serious
+menace to our health.</p>
+
+<p>With the wide prevalence of bovine and human tuberculosis it is little
+wonder that nearly every human being becomes more or less infected at some
+period of life. Autopsies on large numbers of individuals in some of our
+great hospitals have shown that as many as ninety-nine per cent. of the
+subjects show tubercular lesions of some kind. While it is true that the
+class of people who would come to autopsy in such public hospitals would
+perhaps be more likely to be tubercular than the average of the community,
+still it can not be denied that a very large degree of infection exists.
+Pearson, from statistics gathered in Europe, has shown that about eighty
+to ninety per cent. of the population have tubercular lesions before the
+age of eighteen. Hamburger found that in Vienna ninety-five per cent. of
+the children of the poor, between twelve and thirteen years of age, were
+infected with tubercular bacilli and he estimates that all would be before
+maturity. According to Doctor Mott, pathologist to the London County
+Asylums, the insane between the ages of fifteen and thirty-five are about
+fifteen times as likely to acquire tuberculosis as the sane are.</p>
+
+<p>Yet the mortality from tuberculosis, great though it be, is obviously not
+in proportion to the enormous degree of infection. The crux of the
+situation is mainly the matter of resistance. From the standpoint of<span class="pagenum"><a name="Page_151" id="Page_151">[Pg 151]</a></span>
+heredity, therefore, the question largely resolves itself into one of the
+inheritance or non-inheritance of constitutional resistance. Some are
+predisposed to be non-resistant and hence succumb.</p>
+
+<p>The work of Karl Pearson<a name='fna_5' id='fna_5' href='#f_5'><small>[5]</small></a> and other recent researches forcibly indicate
+that hereditary constitutional predisposition is one of the chief factors
+concerned in subjects who develop well defined attacks of the disease. Yet
+we must not forget that there are degrees of susceptibility and that
+therefore a constitutional predisposition which might be of little
+significance under good average conditions of nutrition and sanitation
+might be insufficient under unfavorable conditions.</p>
+
+<p>Before we can make any relatively accurate estimate of the exact degree to
+which the malady is based on inheritance we must have more data. Many
+difficulties beset the path of the investigator. In the first place, when
+one gets back a generation or two he finds that diagnosis was crude and
+uncertain; a given malady may or may not have been tuberculosis. The main
+error however was probably on the side of not recognizing it in mild or
+obscure cases. Then again the questions of virulence of the infection, of
+size and frequency of the dose, etc., are also complicating factors.
+Moreover, in very many cases the infection is a mixed one and hence we are
+dealing with other factors than straight tuberculosis.</p>
+
+<p><b>Two Individuals of Tubercular Stocks Should Not Marry.&mdash;</b>However,
+sufficient is now known of the<span class="pagenum"><a name="Page_152" id="Page_152">[Pg 152]</a></span> inheritance of susceptibility to the
+disease that we can have little conscience toward the welfare of the race
+if we in any way countenance the marriage of two individuals who come each
+of tubercular strains, and marriage of even a normal person into a badly
+tainted strain, where the one married is tubercular, is extremely
+hazardous looked at from the standpoint of the children likely to be born
+of such a union. The Supreme Court of New York recently held that the
+fraudulent concealment of tuberculosis by a person entering into a
+marriage relation is ground for the annulment of the marriage.</p>
+
+<p><b>Special Susceptibility Less of a Factor in Many Diseases.&mdash;</b>With some
+diseases such as leprosy, typhoid fever, smallpox and cholera there seems
+to be less a question of special susceptibility since nearly all persons
+are vulnerable. Yet in cases of typhoid, at least, there are some
+indications that certain families are more likely to take the disease than
+others under similar exposure. We know of no inherited effects of such
+diseases, however. For instance, children of lepers do not inherit leprosy
+and if kept out of leper districts remain normal.</p>
+
+<p><b>Deaf-Mutism.&mdash;</b>In certain abnormal states there is danger of confusing
+similar conditions which may have two entirely different sources of
+origin. Deafness, for example, may be strictly inborn as the outcome of a
+germinal variation or it may result from extraneous influences such as
+accidents, infective diseases, neglected tonsils and the like. The former
+is inheritable, the latter not. Bell in 1906 in a special census report to
+the United States government showed<span class="pagenum"><a name="Page_153" id="Page_153">[Pg 153]</a></span> that deaf-mutism is markedly
+hereditary, particularly where deaf-mutes intermarry as they are prone to
+do. Fay&#8217;s extensive studies on <i>Marriage of the Deaf in America</i> also
+demonstrate the hereditary nature of the congenital forms of deafness. Cut
+off as such individuals are from communication with normal people, the
+association of the two sexes in special schools and institutions is of
+course highly conducive to such marriages. The defect seems to behave in
+the manner of a Mendelian recessive. Two deaf-mutes should not have
+children and yet such marriages are occurring every day. Even if two
+persons marry from families which tend to become hard of hearing the
+evidence indicates that their children are likely also to develop this
+partial deafness as they grow older, although it seems safe for a person
+of such tendency to marry into a family without it.</p>
+
+<p><b>Gout.&mdash;</b>In such disorders as gout there is little question but that a
+tendency to it runs in families. On the other hand it may also be acquired
+without special susceptibility. There is no evidence, however, that
+because a father has gout the effect of the gout is reflected on his
+germ-cells and the son has gout as a result. Indeed, often a son who
+becomes gouty was born long before the father became gouty. Son and father
+both have gout then, because each has innate germinal tendencies which
+when subjected to certain evocative stimuli become expressed as gout.</p>
+
+<p><b>Nervous and Mental Diseases.&mdash;</b>Inasmuch as the question of nervous and
+mental diseases has become one of such overshadowing importance at the
+present day, a discussion of the subject at some length will be<span class="pagenum"><a name="Page_154" id="Page_154">[Pg 154]</a></span> presented
+in a separate chapter. I shall merely point out here that the general
+verdict of experts in nervous and mental disorders is to the effect that
+externally induced mental disorders are of rare occurrence except as the
+result of general poisoning or enfeeblement of the system in some way, or
+by traumatic conditions such as a blow on the head, and that there is no
+evidence of the transmission of the effects of such conditions. In most
+cases of insanity, supposedly caused by fright or worry, a close study of
+the family stock will reveal nervous instability of some kind. The
+supposed cause has been merely the precipitating stimulus which has
+brought to expression a dormant weakness of germinal origin. The stress
+and strain of modern life is particularly likely to test out and reveal
+such neurally unstable individuals.</p>
+
+<p><b>Other Disorders Which Have Hereditary Aspects.&mdash;</b>Space will not permit
+discussion of various other specific disorders which are known to have
+important hereditary aspects, although none shows any convincing evidence
+of having become hereditary in nature through first affecting the soma.
+Some of these, such as epilepsy and other nervous affections,
+tuberculosis, color-blindness, cataract and various malformations, have
+already been mentioned. Others that may be listed are cancer,
+arterio-sclerosis, obesity and certain forms of rheumatism, and of heart
+and kidney diseases. In practically all of these cases in which heredity
+enters as a factor the condition is one of inheriting a special
+susceptibility and not the disease itself. Which means simply that the
+disorder in question<span class="pagenum"><a name="Page_155" id="Page_155">[Pg 155]</a></span> is much more easily called forth in such persons by
+appropriate bacterial or other stimulus, than in the case of the normal
+individual.</p>
+
+<p><b>Induced Immunity Not Inherited.&mdash;</b>Lastly, it is well known that various
+animals, including man, after recovery from an attack of any one of
+certain diseases, become more or less immune from further attacks of the
+same disease. Moreover in some instances as in inoculation against typhoid
+or diphtheria, immunity may be artificially induced by means of
+anti-toxins. The question arises as to whether such immunity is
+transmitted to offspring. Experiments have been made (see <i>Bulletin No.
+30, U. S. Hygienic Laboratory</i>) to test this and it has been found that
+the condition is not inherited. Young guinea-pigs, for instance, born of
+mothers immunized during pregnancy are immune at birth but they lose their
+immunity in the course of a few weeks. The effect is clearly one of direct
+transference from the blood of the mother. The same temporary immunity can
+be produced in the young, in fact, by merely having them nurse from an
+immunized mother.</p>
+
+<p><b>Non-Inheritance of Parental Modifications Has Social, Ethical and
+Educational Significance.&mdash;</b>Like many other biological conclusions these
+relative to the non-inheritance of parental modifications are of extreme
+importance to humanity. It is clear that they have not only physical but
+social, ethical and educational significance. For if the education which
+we give our children of to-day, or the desirable moral conduct which we
+inculcate does not affect the <span class="pagenum"><a name="Page_156" id="Page_156">[Pg 156]</a></span>offspring of succeeding generations through
+inheritance, then the actual progress of the race is much slower than is
+commonly supposed, and the advance of modern over ancient times lies more
+in an improvement in extraneous conditions through invention and the
+accumulation and rendering accessible of knowledge, than in an actual
+innate individual superiority. And when we face the issue squarely we have
+to admit that there is no more indication of the inheritance of parentally
+acquired characters as regards customs, knowledge, habits and moral
+traditions than there is of physical features. In fact, if such
+acquirements were inherited then we should soon have a race which would
+naturally, spontaneously as it were, do what its ancestors did with
+effort. Yet we do not find the children in our schools reading, doing sums
+and developing proper social relations without ceaseless prompting and
+urging on the part of the teacher. Indeed I can testify that this
+necessity carries over even into a university. In short, the habits and
+standards of each generation have to be instilled into the succeeding
+generation.</p>
+
+<p><b>No Cause for Discouragement.&mdash;</b>At first glance when we realize that
+notwithstanding our individual advancement, that in spite of all our
+painstaking efforts toward self-improvement, we can not add one jot or
+tittle to the native ability of our children, that, aside from possible
+advantageous germinal variations, they will have to start in at
+approximately the same level as we did, and like us will have to struggle,
+or be coaxed, pulled or spurred up to the higher reaches of<span class="pagenum"><a name="Page_157" id="Page_157">[Pg 157]</a></span> attainments,
+we are apt to feel discouraged and to look on heredity as the hand of fate
+which irrevocably bars progress. But there is another side to the picture.
+This very fact of heredity which can not be altered at will is the
+conservative factor which maintains the excellence of our standard strains
+of plants and animals, and sustains man himself at his present level of
+accomplishment. While we are denied advancement through the efforts of the
+flesh, we are also largely protected from our misfortunes and follies, as
+witness the non-inheritance of mutilations, of various maladies of
+extrinsic origin, or of personally acquired bad habits.</p>
+
+<p><b>Improved Environment Will Help Conserve the Superior Strains When They Do
+Appear.&mdash;</b>If we can not hand on to our descendants a personally enhanced
+blood heritage, we at least can do our share toward building up a social
+heritage of established truth, of efficient institutions and of
+stimulating ideals, through which their dormant capacities may be led to
+expand more surely and more effectively to their uttermost limits. Each
+advance in such social heritage will tend more and more to create an
+atmosphere which will make it sure that the occasional real progressive
+and permanent variations which occur from time to time will find adequate
+expression and preservation in future lines of descendants. It will reduce
+the numbers of our &#8220;mute, inglorious Miltons&#8221; by more certainly disclosing
+the individual of exceptional talents and insuring for him an opportunity
+of revealing them to the best advantage. Above all, since surrounding
+influences are especially powerful on<span class="pagenum"><a name="Page_158" id="Page_158">[Pg 158]</a></span> young and developing organisms, we
+should realize that great care must be exercised in behalf of the young
+child to secure an environment which is saturated with wholesome
+influences. For it is a rule of development that if the environment is
+faulty the organism is impaired.</p>
+
+
+
+<p>&nbsp;</p><p>&nbsp;</p>
+<hr style="width: 50%;" />
+<p><span class="pagenum"><a name="Page_159" id="Page_159">[Pg 159]</a></span></p>
+<h2><a name="CHAPTER_VI" id="CHAPTER_VI"></a>CHAPTER VI</h2>
+<p class="title">PRENATAL INFLUENCES</p>
+
+
+<p><b>All That a Child Possesses at Birth Not Necessarily Hereditary.&mdash;</b>We come
+now to the more specific discussion of what may happen to offspring of
+mammals, and particularly man, in the interval between fertilization and
+birth; that is, during the intra-maternal period. We have already seen
+that anything affecting the offspring during this period has to be
+reckoned as environmental, our formula reading, Mammal = germ +
+intra-maternal environment + external environment. It is evident, then,
+that all that a child possesses at birth is not necessarily hereditary,
+since the unborn child may be influenced by conditions prevailing in
+either parent.</p>
+
+<p><b>The Myth of Maternal Impressions.&mdash;</b>In order to clear the way for more
+urgent matters let us first inquire into the question of the production of
+changes in the unborn child as a result of &#8220;maternal impressions.&#8221; As the
+tale generally goes, structural changes are produced in the unborn child
+corresponding to some mental experience of the mother, usually a vivid
+impression of strong emotion, but when a given individual is pinned down
+to sources, it is usually a case of hearsay.</p>
+
+<p>Stock examples are: The mother sees a mouse with the result that a
+mouse-shaped birthmark occurs<span class="pagenum"><a name="Page_160" id="Page_160">[Pg 160]</a></span> on the child; or she sees a crushed hand
+and in consequence bears a child later with some of the bones of the hand
+missing; the mother touches her body when frightened and thus marks the
+unborn child on the corresponding part of the body; or she produces beauty
+in the child by long contemplation of a picture of a beautiful child; and
+so on almost endlessly. The favorite is usually the production of a red
+birthmark or marks on the child&#8217;s body by strong desire on the part of the
+mother for strawberries, tomatoes, etc.&mdash;the fruit must be red since the
+mark is red&mdash;or by fright from seeing a fire. As a matter of fact it is
+not uncommon for the capillary blood vessels of the skin of a new-born
+infant to remain dilated in spots instead of contracting as they normally
+should do. The result is more or less of a red or &#8220;flame&#8221; spot. It is easy
+to see, therefore, why such birthmarks are so frequently referred back by
+the credulous mother to her desire for or fear of some red object.</p>
+
+<p>An analysis of the case of a child shuddering at the sight of peaches is
+of interest in this connection. The child showed the greatest aversion to
+peaches, particularly to the fuzzy covering. The mother&#8217;s explanation was
+that peaches were unusually plentiful the year the child was born and that
+she had worked hour after hour at peeling and canning peaches shortly
+before his birth until she had become thoroughly sick of them. This
+acquired aversion on her part she believed had been transferred to the
+child. A few questions revealed the fact, however, that the mother,
+herself, had never liked peaches and when asked if they were distasteful
+to any other member of her own<span class="pagenum"><a name="Page_161" id="Page_161">[Pg 161]</a></span> family she exclaimed, &#8220;Oh, yes, my mother
+would shudder and shake if a peach were brought near her.&#8221; And there we
+have it. The idiosyncrasy was an inherited one as many similar
+peculiarities are. The mental impression produced in the mother by her own
+experience with peaches had nothing to do with its occurrence in the
+child.</p>
+
+<p>Very frequently also one encounters the mother who is sure she has
+engendered musical ability in her child by constant practise and study of
+music during pregnancy. The child is musical; what better evidence does
+one want! It seems never to occur to such a mother that the child is
+musically inclined because she herself is, as is evinced by her own desire
+in the matter even if she is not a skillful performer.</p>
+
+<p>When we take into account the extreme credulity of many people, the
+unconscious tendency of mankind to give a dramatic interpretation to
+events where causes are not certainly known, the hosts of coincidences
+that occur in life, and the multitude of cases where something should
+happen but nothing does, we are compelled to believe that the whole matter
+of direct specific influence of the mother&#8217;s mind on the developing fetus
+is a myth. After seeing the conditions which prevail in Mendelism, for
+example, it will take strong faith to believe that a mother with duplex
+brown eyes can &#8220;think&#8221; or &#8220;will&#8221; blue eyes on her baby, yet this would be
+a mild procedure compared to some we are asked to accept by believers in
+the transmission of maternal impressions. Most of all, however, when we
+recall the actual relation between the embryo and the mother&mdash;a narrow
+umbilical cord is the sole means of<span class="pagenum"><a name="Page_162" id="Page_162">[Pg 162]</a></span> communication between the two&mdash;the
+physical impossibility of a connection between some particular mental
+happening of the mother and a corresponding specific modification in the
+fetus becomes evident. For there are no nerves in the umbilical cord, the
+only path of communication between mother and fetus being the indirect one
+by way of the blood stream. Even this method of communication is limited
+inasmuch as the mother&#8217;s blood does not circulate through the blood
+vessels of the fetus. Gaseous and dissolved substances are merely
+interchanged through the thin walls of the capillary blood vessels in the
+placenta.</p>
+
+<p><b>Injurious Prenatal Influences.&mdash;</b>However, the denial that a particular
+mental impression of the mother is associated with a particular structural
+defect in a child does not carry with it the implication that prenatal
+influences of all kinds are negligible factors. On the contrary any
+deleterious effect which can reach the fetus through absorption from the
+blood of the mother may be of grave consequence. There is not the least
+doubt that malnutrition or serious ill-health on the part of the mother
+often has a prejudicial effect on the unborn offspring. Severe shock or
+grief, worry, nervous exhaustion, the influence of certain diseases,
+poisons in the blood or tissues of the parent, such as lead, mercury,
+phosphorus, alcohol and the like, may all act detrimentally, but they
+operate either by rendering nutrition defective, by direct poisoning, or
+by generating toxins in the blood of the parent which then poison the
+fetus. Among the latter may be mentioned the toxic products of
+tuberculosis and certain other bacterial diseases. Such factors operating
+on<span class="pagenum"><a name="Page_163" id="Page_163">[Pg 163]</a></span> the unborn young or even on the germ-cells may cause malformations,
+arrests of development, instabilities of the nervous system, and general
+physical or mental weakness. The effects are general, however, and not
+specific.</p>
+
+<p>To distinguish certain of these prenatal effects, particularly those of
+certain diseases or poisons, from true hereditary influences they are
+frequently spoken of as cases of <i>transmission</i> rather than inheritance
+from parents. Some writers use the technical term <i>blastophthoria</i>, or
+false-heredity, extending the meaning so as to include also any damage
+that might be inflicted on the germ-cells.</p>
+
+<p><b>Lead Poisoning.&mdash;</b>By way of illustration of how certain cumulative poisons
+may act we may examine a tabulation of eighty-one cases of lead poisoning
+as reported by Constantin Paul (Fig. 29, <a href="#Page_164">p. 164</a>).</p>
+
+<p>The table requires little comment. The disastrous effects of such
+poisoning are apparent in every class of cases. The sixth class where the
+husband alone was exposed to lead shows that the poison can operate
+directly through the germ-cell. Other observers note that in the children
+of workers in lead, there is a distressing frequency of feeble-mindedness
+and epilepsy.</p>
+
+<p>That lead poisoning operating through the germ-cells of the father can
+affect the development of the young harmfully is well shown in Fig. 30, <a href="#Page_165">p. 165</a>,
+which is a photograph of two young rabbits from the same litter The
+white young one is from a normal albino mother mated to an albino father
+which had received lead treatment. The pigmented young one is from the
+same albino mother by a normal pigmented father.<span class="pagenum"><a name="Page_164" id="Page_164">[Pg 164]</a></span> Although the white
+father was considerably larger than the pigmented father, nevertheless the
+young of the former, because of the harmful effects of the lead, is
+distinctly smaller and less lively. A number of litters, each from the
+same mother but in part from a lead-poisoned father and in part from a
+normal father, have been secured. All show more or less the same results.
+The experiments are still in progress in the department of experimental
+breeding at the University of Wisconsin.</p>
+
+<table border="0" cellpadding="0" cellspacing="0" summary="table">
+<tr><td class="btr" colspan="2">&nbsp;</td>
+    <td class="btr" align="center">Number<br />of<br />cases.</td>
+    <td class="btr" align="center">Number<br />of<br />pregnancies.</td>
+    <td class="btr" align="center">Abortions,<br />premature<br />labor, and<br />stillbirths.</td>
+    <td class="btr" align="center">Infants<br />born<br />living.</td>
+    <td class="bt" align="center">Remarks.</td></tr>
+<tr><td class="bt" valign="top">1.</td>
+    <td class="btr" valign="top">Mother showing symptoms<br />of plubism</td>
+    <td class="btr" align="center">4</td>
+    <td class="btr" align="center">15</td>
+    <td class="btr" align="center">13</td>
+    <td class="btr" align="center">2</td>
+    <td class="bt" valign="bottom">One infant died<br /><span style="margin-left: 1em;">within 24 hours.</span></td></tr>
+<tr><td colspan="2" class="br">&nbsp;</td>
+    <td class="br">&nbsp;</td>
+    <td class="br">&nbsp;</td>
+    <td class="br">&nbsp;</td>
+    <td class="br">&nbsp;</td></tr>
+<tr><td valign="top">2.</td>
+    <td class="br" valign="top">Mother working in type<br />foundry, all of whose<br />previous pregnancies had<br />been normal</td>
+    <td class="br" align="center">5</td>
+    <td class="br" align="center">36</td>
+    <td class="br" align="center">29</td>
+    <td class="br" align="center">7</td>
+    <td class="dent" valign="bottom">Four of these died<br /><span style="margin-left: 1em;">in first year.</span></td></tr>
+<tr><td colspan="2" class="br">&nbsp;</td>
+    <td class="br">&nbsp;</td>
+    <td class="br">&nbsp;</td>
+    <td class="br">&nbsp;</td>
+    <td class="br">&nbsp;</td></tr>
+<tr><td valign="top">3.</td>
+    <td class="br" valign="top">Mother who during period<br />of work in type foundry<br />had five pregnancies</td>
+    <td class="br" align="center">1</td>
+    <td class="br" align="center">5</td>
+    <td class="br" align="center">5</td>
+    <td class="br" align="center">0</td>
+    <td class="dent" valign="bottom">After ceasing to<br /><span style="margin-left: 1em;">work had</span><br /><span style="margin-left: 1em;">healthy child.</span></td></tr>
+<tr><td colspan="2" class="br">&nbsp;</td>
+    <td class="br">&nbsp;</td>
+    <td class="br">&nbsp;</td>
+    <td class="br">&nbsp;</td>
+    <td class="br">&nbsp;</td></tr>
+<tr><td valign="top">4.</td>
+    <td class="br" valign="top">Mother working intermittently<br />in type foundry; while<br />working there</td>
+    <td class="br" align="center">3</td>
+    <td class="br" align="center">3</td>
+    <td class="br" align="center">3</td>
+    <td class="br" align="center">0</td>
+    <td class="dent" valign="bottom">When away from<br /><span style="margin-left: 1em;">work for some</span><br /><span style="margin-left: 1em;">period of time</span><br />
+    <span style="margin-left: 1em;">gave birth to</span><br /><span style="margin-left: 1em;">healthy children.</span></td></tr>
+<tr><td colspan="2" class="br">&nbsp;</td>
+    <td class="br">&nbsp;</td>
+    <td class="br">&nbsp;</td>
+    <td class="br">&nbsp;</td>
+    <td class="br">&nbsp;</td></tr>
+<tr><td valign="top">5.</td>
+    <td class="br" valign="top">Mother in whom blue line<br />on gum the only sign of<br />lead poisoning</td>
+    <td class="br" align="center">6</td>
+    <td class="br" align="center">29</td>
+    <td class="br" align="center">21</td>
+    <td class="br" align="center">8</td></tr>
+<tr><td colspan="2" class="br">&nbsp;</td>
+    <td class="br">&nbsp;</td>
+    <td class="br">&nbsp;</td>
+    <td class="br">&nbsp;</td>
+    <td class="br">&nbsp;</td></tr>
+<tr><td class="bb" valign="top">6.</td>
+    <td class="bbr" valign="top">Husband alone exposed to<br />lead</td>
+    <td class="bbr" align="center">?</td>
+    <td class="bbr" align="center">32</td>
+    <td class="bbr" align="center">12</td>
+    <td class="bbr" align="center">20</td>
+    <td class="bb" valign="bottom">Of these, eight<br /><span style="margin-left: 1em;">died in first year,</span><br />
+    <span style="margin-left: 1em;">four in second,</span><br /><span style="margin-left: 1em;">five in third.</span></td></tr></table>
+
+<p class="center"><span class="smcap">Fig. 29</span></p>
+
+<p class="center">Tabulation of eighty-one cases of lead poisoning recorded by Constantin Paul (from Adami).</p>
+
+
+<p>&nbsp;<span class="pagenum"><a name="Page_165" id="Page_165">[Pg 165]</a></span></p>
+<div class="figcenter"><img src="images/img29.jpg" alt="" /></div>
+<p class="center"><span class="smcap">Fig. 30</span></p>
+
+<p class="descrip">Photograph of young rabbits from the same litter, the smaller one stunted
+by lead-poisoning of its father (Courtesy of Professor L. J. Cole).</p>
+<p>&nbsp;</p>
+
+<p><span class="pagenum"><a name="Page_166" id="Page_166">[Pg 166]</a></span><b>The Expectant Mother Should Have Rest.&mdash;</b>The mere matter of rest on the
+part of the pregnant mother is, judging from the work of Pinard, a
+Frenchman, and his pupils, an important one. In a number of detailed
+investigations they have shown that rest on the part of the working mother
+during the last three months before the child is born results in the
+production of markedly larger and more robust children than those born of
+mothers equally healthy but who have not had such rest. Moreover the
+danger of premature birth is considerably lessened.</p>
+
+<p><b>Too Short Intervals Between Children.&mdash;</b>Too short an interval between
+childbirths would also seem to be an infringement on the rights of the
+child as well as of the mother. Thus Doctor R. J. Ewart (&#8220;The Influence of
+Parental Age on Offspring,&#8221; <i>Eugenic Review</i>, October, 1911) finds that
+children born at intervals of less than two years after the birth of the
+previous child still show at the age of six a notable deficiency in
+height, weight and intelligence, when compared with the children born
+after a longer interval, or even with first-born children.</p>
+
+<p><b>Our Duty to Safeguard Motherhood.&mdash;</b>Doubtless the unventilated factory and
+tenement also do their share, even though we can give no exact
+quantitative measure of it. Obviously, it becomes a civic duty to protect
+as much as possible all members of our social system from such injurious
+factors as have just been discussed. It is particularly necessary to
+safeguard mothers before confinement, especially working mothers.</p>
+
+<p><b>Expectant Mothers Neglected.&mdash;</b>According to the<span class="pagenum"><a name="Page_167" id="Page_167">[Pg 167]</a></span> claims of life insurance
+men, expectant mothers are the most neglected members of our population.
+Doctor Van Ingen, of New York City, estimates that ninety per cent. of
+women in this country are wholly without prenatal care. Yet every
+prospective mother should be taught the probable meaning of such symptoms
+as headache, hemorrhages, swelling of the feet and disturbed vision. She
+should realize the importance of submitting a sample of urine for analysis
+at least once a month before childbirth and twice a month for a while
+thereafter. She should be specially informed regarding work, exercise,
+diet and dress. A recent government bulletin written by Mrs. Max West
+which may be had free by writing to the Children&#8217;s Bureau, Department of
+Labor, Washington, D. C., gives much useful information on this subject.</p>
+
+
+<p>&nbsp;</p>
+<p class="center">ALCOHOLISM</p>
+
+<p><b>Unreliability of Much of the Data.&mdash;</b>One of the most important poisons that
+plays a prominent part among ante-natal influences is alcohol. But when it
+comes to a study of the problem of alcoholism from the standpoint of
+heredity and parental influences we meet with many difficulties, prominent
+among which are the inaccuracy and unreliability of many of the statistics
+brought forward in this connection. Many of the results are vitiated by
+the prejudices of propagandists who propose to make a case either for or
+against alcohol as a beverage whether or not the facts justify their
+conclusions. When one tries to view the matter with an open mind he finds
+that there is a <span class="pagenum"><a name="Page_168" id="Page_168">[Pg 168]</a></span>deplorable lack of statistics which are not susceptible
+to more than one interpretation. However, using as much as possible what
+seems to be unbiased data, the evidence is almost wholly against alcohol
+as a beverage, at least to any immoderate extent.</p>
+
+<p><b>Alcohol a Germinal or Fetal Poison.&mdash;</b>The bad effects as far as offspring
+are concerned reveal themselves in the main under the category of &#8220;false
+heredity,&#8221; i. e., germinal or fetal poisonings rather than of heritable
+changes induced in the germ-cells. Most investigators feel that there are
+too many criminal, imbecile, insane and unhealthy persons among the
+offspring of drunkards to dismiss the matter as a coincidence. In an
+investigation of Imbault, for example, we find recorded of one hundred
+tuberculous children that while forty-one were of tuberculous parentage,
+thirty-six per cent, were the offspring of inebriates. Furthermore Imbault
+cites the observations of Arriv&eacute; on 1,506 cases of juvenile meningitis to
+the effect that this malady is twice as frequent in the children of
+alcoholic as in those of tuberculous parentage. It has been proved by
+Nicloux (<i>L&#8217;Obstetrique</i>, Vol. 99, 1900) that in dogs and guinea-pigs
+alcohol passes through the placenta and may be detected in fetal tissues;
+hence it is in position to influence the fetus. He found that in a very
+short time the amount of alcohol in the blood of the fetus about
+paralleled that in the blood of the mother.</p>
+
+<p><b>Progressive Increase in Death-Rate of Offspring of Inebriate Women.&mdash;</b>In an
+investigation on the effects of parental alcoholism on the offspring,
+Sullivan (<i>Journal of Mental Science</i>, Vol. 45, 1899) gives<span class="pagenum"><a name="Page_169" id="Page_169">[Pg 169]</a></span> some
+important figures. To avoid other complications he chose female drunkards
+in whom no other degenerative features were evident. He found that among
+these the percentage of abortions, still-births and deaths of infants
+before their third year was 55.8 per cent. as against 23.9 per cent. in
+sober mothers. In answer to the objection that this high percentage may be
+due merely to neglect, and not to impairment of the fetus by alcoholism,
+he points out the fact based on the history of the successive births, that
+there was a progressive increase in the death-rate of offspring in
+proportion to the length of time the mother had been an inebriate, thus:</p>
+
+<table border="0" cellpadding="0" cellspacing="0" summary="table">
+<tr><td class="btr">&nbsp;</td>
+    <td class="btr" align="center">No. of<br />cases</td>
+    <td class="btr" align="center">Per cent.<br />born dead</td>
+    <td class="btr" align="center">Per cent.<br />dying<br />before 3</td>
+    <td class="bt" align="center">Total<br />percentage</td></tr>
+<tr><td class="btr">First births</td>
+    <td class="btr" align="center"><span style="margin-left: .5em;">80</span></td>
+    <td class="btr" align="center"><span style="margin-left: .25em;">6.2</span></td>
+    <td class="btr" align="center">27.5</td>
+    <td class="bt" align="center">33.7</td></tr>
+<tr><td class="br">Second births</td>
+    <td class="br" align="center"><span style="margin-left: .5em;">80</span></td>
+    <td class="br" align="center">11.2</td>
+    <td class="br" align="center">40.8</td>
+    <td class="dent" align="center">50.0</td></tr>
+<tr><td class="br">Third births</td>
+    <td class="br" align="center"><span style="margin-left: .5em;">80</span></td>
+    <td class="br" align="center"><span style="margin-left: .25em;">7.6</span></td>
+    <td class="br" align="center">45.0</td>
+    <td class="dent" align="center">52.6</td></tr>
+<tr><td class="br">Fourth and fifth</td>
+    <td class="br" align="center">111</td>
+    <td class="br" align="center">10.8</td>
+    <td class="br" align="center">54.9</td>
+    <td class="dent" align="center">65.7</td></tr>
+<tr><td class="bbr">Sixth to tenth</td>
+    <td class="bbr" align="center"><span style="margin-left: .5em;">93</span></td>
+    <td class="bbr" align="center">17.2</td>
+    <td class="bbr" align="center">54.8</td>
+    <td class="bb" align="center">72.0</td></tr></table>
+
+<p><b>Views of a Psychiatrist on Alcohol.&mdash;</b>Forel, who for years was the
+psychiatrist at the head of a large insane asylum at Zurich, Switzerland,
+has this to say about the effects of narcotic poisons and alcohol in
+particular:</p>
+
+<div class="blockquot"><p>&#8220;The offspring tainted with alcoholic blastophthoria suffer various
+bodily and physical anomalies, among which are dwarfism, rickets, a
+predisposition to tuberculosis and epilepsy, moral idiocy, and idiocy
+in general, a predisposition to crime and mental diseases, sexual
+perversions, loss of suckling in women, and many other misfortunes.&#8221;</p></div>
+
+<p><span class="pagenum"><a name="Page_170" id="Page_170">[Pg 170]</a></span>In another passage he<a name='fna_6' id='fna_6' href='#f_6'><small>[6]</small></a> remarks as follows:</p>
+
+<div class="blockquot"><p>&#8220;But what is of much greater importance is the fact that acute and
+chronic alcoholic intoxication deteriorates the germinal protoplasm of
+the procreators.... The recent researches of Bezzola seem to prove
+that the old belief in the bad quality of children conceived during
+drunkenness is not without foundation. Relying on the Swiss census of
+1900, in which there figure nine thousand idiots, and after careful
+examination of the bulletins concerning them, this author has proved
+that there are two acute annual maximum periods for the conception of
+idiots (calculated from nine months before birth); the periods of
+carnival and vintage, when the people drink most. In the wine-growing
+districts the maximum conception of idiots is enormous, while it is
+almost nil at other periods. Moreover, these two maximum periods come
+at the time of year when conception is at a minimum among the rest of
+the population, the maximum of normal conceptions occurring at the
+beginning of summer.&#8221;</p></div>
+
+<p>Another interpretation of Bezzola&#8217;s results has been suggested to the
+effect that the license of these periods enables the defective members of
+the community, such as the feeble-minded, an opportunity of mating more
+readily and that consequently the result is direct inheritance of idiocy
+and allied defects instead of idiocy produced through alcoholic poisoning
+of the parental germ-cell.</p>
+
+<p><b>Other Views.&mdash;</b>There are indeed many competent investigators who believe
+that alcoholism in parents has little or no part in the direct production
+of mental defects in children. For instance, Tredgold quotes<span class="pagenum"><a name="Page_171" id="Page_171">[Pg 171]</a></span> Doctor
+Ireland&#8217;s observations that although at New Year, when the fishermen
+return, the whole population of certain villages in Scotland gets drunk,
+there is no noticeable excess of defectives born nine months later, and
+remarks further that, &#8220;I have histories of idiots conceived under such
+circumstances, but so I have of normal children, and my opinion is, that
+while this may be a cause in some cases, the number of instances in this
+country at any rate is exceedingly small.&#8221; Again, Goddard, one of our best
+known American students of feeble-mindedness, who has made careful study
+of this point under especially favorable conditions, feels that his data
+do not prove that alcoholism of either the father or the mother causes
+feeble-mindedness in the child. He concludes, &#8220;Everything seems to
+indicate that alcoholism itself is only a symptom; that it for the most
+part occurs in families where there is some form of neurotic taint,
+especially feeble-mindedness.&#8221; Goddard, however, in common with many other
+observers, notes that miscarriages and deaths in infancy are far higher
+among inebriates than among abstainers.</p>
+
+<p>Doctor Mj&ouml;en cites an interesting parallel between the increase of
+feeble-mindedness in Norway and a period from 1816 to 1835, when every one
+was permitted to distil brandy. In some districts many of the farmers
+distilled brandy from corn and potatoes, and in such regions during this
+period feeble-mindedness increased nearly one hundred per cent. Later the
+home distillation of brandy was stopped. According to Doctor Mj&ouml;en, &#8220;The
+enormous increase in idiots came<span class="pagenum"><a name="Page_172" id="Page_172">[Pg 172]</a></span> and went with the brandy.&#8221; He is
+inclined to believe, however, that the alcohol operated injuriously mainly
+on stocks already defective.</p>
+
+<p><b>The Affinity of Alcohol for Germinal Tissue.&mdash;</b>Nicloux and Renault have
+shown that alcohol has a decided affinity for the reproductive glands. In
+individuals who have recently taken alcohol the proportion of alcohol in
+the gonads is soon almost equal to the amount found in the blood. Thus in
+experiments on mammals it was found that the proportion of alcohol in the
+ovary to that in the blood was as three to five, and in the testis as two
+to three. This would afford abundant opportunity for alcohol to act
+directly on the spermatozoon or the ovum.</p>
+
+<p>A number of different investigators concur in finding that the germ-glands
+of the male human inebriate in many cases show more or less atrophy and
+other degenerative changes. In guinea-pigs which have been repeatedly
+intoxicated with alcohol, Stockard found that while he could detect no
+visible abnormality in the gonad, nevertheless their defective and
+weakened progeny showed that the germ-cells had been affected.</p>
+
+<p><b>Innate Degeneracy Versus the Effects of Alcohol.&mdash;</b>Many observations on
+human beings have been brought forward which at first sight seem to
+indicate that noticeable defects, particularly mental and nervous, occur
+with appalling frequency in children resulting from conception during
+intoxication, although, unfortunately, the evidence is rarely clear as to
+whether the defects are really due to the effects of the alcohol or to the
+fact that the parent or parents were degenerate to begin with.</p>
+
+<p><span class="pagenum"><a name="Page_173" id="Page_173">[Pg 173]</a></span>A very interesting human case cited by Forel on the authority of
+Schweighofer is that of a normal woman who had three sound children when
+married to a normal man. After the death of this husband she married an
+inebriate by whom she had three other children. One of these suffered from
+infantilism, one turned out to be a drunkard, and the third became a
+social degenerate and drunkard. Moreover the first two contracted
+tuberculosis, although hitherto the family stock had been free from this
+malady. Ultimately the woman married again and by this third husband, who
+was normal, she again had sound children. Similar cases might be cited,
+as, for example, a record of eighty-three epileptics, of whom sixty had
+drunken parents, but it can be urged against all of them, of course, that
+the defective offspring were due to an innate degeneracy of the drunken
+parent which made him a drunkard rather than to the effects of the alcohol
+he took. While one is skeptical as to the validity of this objection in
+all of the many cases which occur with such monotonous frequency in man,
+there is no way of escaping such an interpretation with the evidence at
+hand. It must be admitted, moreover, that there are many families with one
+or both parents alcoholic in which the children are not mentally
+defective.</p>
+
+<p><b>Experimental Alcoholism in Lower Animals.&mdash;</b>Many of the objections that
+exist in the case of man, however, do not apply in that of lower animals.
+If normal animals are experimentally alcoholized and are shown to produce
+defective offspring under such conditions, then in their cases at least,
+the disorders in the offspring must be due to the effects of alcohol and<span class="pagenum"><a name="Page_174" id="Page_174">[Pg 174]</a></span>
+not to an innately degenerate condition of the parent. Disorders similar
+to some of those seen in the children of alcoholics do actually result in
+alcoholized animals of one kind or another.</p>
+
+<p>Against the earlier experiments on animals it has been urged that too few
+individuals were used to give conclusive results, but this objection can
+not be brought against the recent experiments of Stockard. While he has
+published accounts of his work in various scientific periodicals lately,
+the reader will find a full statement of his own experiments, together
+with a review of the whole subject of experimental alcoholism in animals
+and the effects on progeny in <i>The American Naturalist</i>, Vol. XLVII,
+November, 1913, together with a useful bibliography.</p>
+
+<p>Before taking up Stockard&#8217;s results we may select a few of the more
+significant experiments made earlier by other investigators.</p>
+
+<p>Laitinen alcoholized rabbits and guinea-pigs. He found that the treated
+individuals had more still-born young than the control, and also that
+growth of the living young was retarded. His alcoholized rabbits and
+guinea-pigs produced more young than did the normal individuals used as a
+control. Laitinen&#8217;s studies on man, together with three other studies of
+the Eugenics Laboratory in London, show that in man also more children are
+born to alcoholics than to normal parents. Goddard&#8217;s investigations in
+America corroborate this fact.</p>
+
+<p>Ceni found that only 43 per cent. of the eggs from alcoholized fowls
+developed normally, as against 77 per cent. of normal development in the
+controls. Moreover<span class="pagenum"><a name="Page_175" id="Page_175">[Pg 175]</a></span> the eggs of alcoholic fowls were shown to be less
+resistant to adverse conditions than normal eggs from the fact that
+fluctuations of temperature at the beginning of incubation kept all the
+alcoholic eggs from developing perfectly, while 27 per cent. of the
+control eggs developed normally under the same adverse circumstances.</p>
+
+<p>Hodge made a pair of dogs alcoholic. Of 23 pups obtained from the pair, 8
+were deformed and 9 were dead; 4 alone were viable. From a control pair of
+dogs 45 pups were obtained, of which 4 were deformed, none were born dead,
+and 41 were viable.</p>
+
+<p><b>Stockard&#8217;s Experiments on Guinea-Pigs.&mdash;</b>Stockard&#8217;s experiments demonstrate
+that the offspring of mammals may be injured or modified in their
+development by treating either parent repeatedly with alcohol. The
+guinea-pigs used in the experiment were all first tested by normal matings
+and found to yield normal offspring. The alcohol was given to them by
+inhalation. It was found to be readily taken into the animals&#8217; blood and
+to produce intoxication. While guinea-pigs alcoholized in this way as
+often as six times a week for two and one-half years would maintain their
+own bodily vigor and health apparently, the deleterious effects on their
+progeny were marked. The defects were general rather than specific,
+although the central nervous system and special sense organs were
+apparently affected most.</p>
+
+<p>Out of 119 total young produced by the alcoholic animals, only 52, or less
+than 44 per cent., survived, whereas out of 64 young produced from normal
+parents used as a control for the experiment, 56, or over<span class="pagenum"><a name="Page_176" id="Page_176">[Pg 176]</a></span> 87 per cent.,
+survived. In some cases alcoholic males were mated with normal females, in
+other, alcoholic females with normal males. In still other instances both
+parents were alcoholic.</p>
+
+<p>The results are summarized in the accompanying table (Fig. 31), taken from
+Stockard&#8217;s paper:</p>
+
+<p class="center"><span class="smcap">Condition of the Offspring from Guinea-Pigs Treated with Alcohol</span></p>
+
+<table border="0" cellpadding="0" cellspacing="0" summary="table">
+<tr><td class="btr" align="center">Condition<br />of the<br />Animals</td>
+    <td class="btr" align="center">Number<br />of<br />Matings</td>
+    <td class="btr" align="center">Negative<br />Result<br />or Early<br />Abortion</td>
+    <td class="btr" align="center">Still-born<br />Litters</td>
+    <td class="btr" align="center">Number<br />Still-born<br />Young</td>
+    <td class="btr" align="center">Living<br />Litters</td>
+    <td class="btr" align="center">Young<br />Dying<br />Soon<br />After<br />Birth</td>
+    <td class="bt" align="center">Surviving<br />Young</td></tr>
+<tr><td class="btr">Alcoholic &#9794; by normal &#9792;</td>
+    <td class="btr" align="center"><span style="margin-left: .5em;">59</span></td>
+    <td class="btr" align="center">25</td>
+    <td class="btr" align="center"><span style="margin-left: .5em;">8</span></td>
+    <td class="btr" align="center">15</td>
+    <td class="btr" align="center">26</td>
+    <td class="btr" align="center">21</td>
+    <td class="bt" align="center">33</td></tr>
+<tr><td class="br">Normal &#9794; by alcoholic &#9792;</td>
+    <td class="br" align="center"><span style="margin-left: .5em;">15</span></td>
+    <td class="br" align="center"><span style="margin-left: .5em;">3</span></td>
+    <td class="br" align="center"><span style="margin-left: .5em;">3</span></td>
+    <td class="br" align="center"><span style="margin-left: .5em;">9</span></td>
+    <td class="br" align="center"><span style="margin-left: .5em;">9</span></td>
+    <td class="br" align="center"><span style="margin-left: .5em;">9</span></td>
+    <td class="dent" align="center">10</td></tr>
+<tr><td class="br">Alcoholic &#9794; by alcoholic &#9792;</td>
+    <td class="br" align="center"><span style="margin-left: .5em;">29</span></td>
+    <td class="br" align="center">15</td>
+    <td class="br" align="center"><span style="margin-left: .5em;">3</span></td>
+    <td class="br" align="center"><span style="margin-left: .5em;">6</span></td>
+    <td class="br" align="center">11</td>
+    <td class="br" align="center"><span style="margin-left: .5em;">7</span></td>
+    <td class="dent" align="center"><span style="margin-left: .5em;">9</span></td></tr>
+<tr><td class="br"><span class="smcap">Summary</span></td>
+    <td class="br" align="center">103</td>
+    <td class="br" align="center">43</td>
+    <td class="br" align="center">14</td>
+    <td class="br" align="center">30</td>
+    <td class="br" align="center">46</td>
+    <td class="br" align="center">37</td>
+    <td class="dent" align="center">52</td></tr>
+<tr><td class="br">Normal &#9794; by normal &#9792;</td>
+    <td class="br" align="center"><span style="margin-left: .5em;">35</span></td>
+    <td class="br" align="center"><span style="margin-left: .5em;">2</span></td>
+    <td class="br" align="center"><span style="margin-left: .5em;">1</span></td>
+    <td class="br" align="center"><span style="margin-left: .5em;">4</span></td>
+    <td class="br" align="center">32</td>
+    <td class="br" align="center"><span style="margin-left: .5em;">4</span></td>
+    <td class="dent" align="center">56</td></tr>
+<tr><td class="br">2d generation by normal</td>
+    <td class="br" align="center"><span style="margin-left: 1em;">3</span></td>
+    <td class="br" align="center"><span style="margin-left: .5em;">0</span></td>
+    <td class="br" align="center"><span style="margin-left: .5em;">0</span></td>
+    <td class="br" align="center"><span style="margin-left: .5em;">0</span></td>
+    <td class="br" align="center"><span style="margin-left: .5em;">3</span></td>
+    <td class="br" align="center"><span style="margin-left: .5em;">0</span></td>
+    <td class="dent" align="center"><span style="margin-left: .5em;">4</span></td></tr>
+<tr><td class="br">2d generation by alcoholic</td>
+    <td class="br" align="center" valign="top"><span style="margin-left: 1em;">3</span></td>
+    <td class="br" align="center" valign="top"><span style="margin-left: .5em;">0</span></td>
+    <td class="br" align="center" valign="top"><span style="margin-left: .5em;">2</span></td>
+    <td class="br" align="center" valign="top"><span style="margin-left: .5em;">5</span><br />1 def.</td>
+    <td class="br" align="center" valign="top"><span style="margin-left: .5em;">1</span></td>
+    <td class="br" align="center" valign="top"><span style="margin-left: .5em;">0</span></td>
+    <td class="dent" align="center" valign="top"><span style="margin-left: .5em;">2</span></td></tr>
+<tr><td class="br">2d generation by 2d generation</td>
+    <td class="br" align="center" valign="top"><span style="margin-left: .5em;">19</span></td>
+    <td class="br" align="center" valign="top"><span style="margin-left: .5em;">7</span></td>
+    <td class="br" align="center" valign="top"><span style="margin-left: .5em;">0</span></td>
+    <td class="br" align="center" valign="top"><span style="margin-left: .5em;">0</span></td>
+    <td class="br" align="center" valign="top">12</td>
+    <td class="br" align="center" valign="top"><span style="margin-left: .5em;">6</span><br />1 def.</td>
+    <td class="dent" align="center" valign="top">13</td></tr>
+<tr><td class="bbr">Female treated during pregnancy</td>
+    <td class="bbr" align="center"><span style="margin-left: 1em;">4</span></td>
+    <td class="bbr" align="center"><span style="margin-left: .5em;">0</span></td>
+    <td class="bbr" align="center"><span style="margin-left: .5em;">0</span></td>
+    <td class="bbr" align="center"><span style="margin-left: .5em;">0</span></td>
+    <td class="bbr" align="center"><span style="margin-left: .5em;">4</span></td>
+    <td class="bbr" align="center"><span style="margin-left: .5em;">1</span></td>
+    <td class="bb" align="center"><span style="margin-left: .5em;">7</span></td></tr></table>
+
+<p class="center"><span class="smcap">Fig. 31</span></p>
+
+<p class="center">Table showing condition of the offspring from guinea-pigs treated with alcohol (after Stockard).</p>
+
+<p>Lines four and five give a comparison between the 103 total matings of all
+treated individuals and 35 normal matings. In the first case almost 42 per
+cent. of the matings gave negative results or early abortions, whereas in
+the normal control matings, failure to yield a full-term litter occurred
+in only two cases. The 103 matings of alcoholic animals gave only 46
+living litters, or about 45 per cent. On the other hand the 35 control
+matings produced 32 living litters, or 91&#189;<span class="pagenum"><a name="Page_177" id="Page_177">[Pg 177]</a></span> per cent. It will be
+observed also that from such of the 103 matings of alcoholics as produced
+young there were 30 still-born, 37 which died soon after birth, and only
+52 surviving young, whereas from the 35 matings of normal individuals
+there were only 4 still-born young, 4 which died soon after birth, and 56
+surviving young.</p>
+
+<p>The bottom line of the table, although, as Stockard points out, containing
+too few cases to prove wholly convincing, indicates that alcoholizing
+erstwhile normal females during pregnancy was not particularly harmful to
+the embryos <i>in utero</i>.</p>
+
+<p>Some of the most interesting results were obtained when offspring termed
+second generation animals, derived from alcoholic parents though not
+themselves treated with alcohol, were mated in various ways. When such
+individuals were mated with normal individuals, although the litters were
+small, the results were normal, the normal mate having seemingly
+counteracted any defects which might have lurked in the second generation
+animal. On the other hand, out of three matings of second generation
+animals with alcoholic individuals, two produced still-born young, of
+which one was markedly deformed, while the third yielded two living young.</p>
+
+<p>However, the most striking results were obtained when two second
+generation individuals, the offspring of alcoholic parents, were bred
+together. Although themselves untreated, these individuals, of which 19
+matings were made, produced as many or more defective young than did their
+alcoholic parents. Seven of the matings were unfruitful. The remaining 12<span class="pagenum"><a name="Page_178" id="Page_178">[Pg 178]</a></span>
+matings gave living litters consisting of 19 individuals in all. Six of
+these showed various nerve disorders (spasms, epileptic-like seizures,
+etc.) soon after birth; one was eyeless and otherwise deformed.</p>
+
+<p><b>Stockard&#8217;s Interpretation.&mdash;</b>Stockard&#8217;s interpretation of his experiments
+is as follows: &#8220;Mammals treated with injurious substances, such as
+alcohol, ether, lead, etc., suffer from the treatments by having the
+tissues of their bodies injured. When the reproductive glands and
+germ-cells become injured in this way they give rise to offspring showing
+weak and degenerative conditions of a general nature, and every cell of
+these offspring having been derived from the injured egg or sperm-cell are
+necessarily similarly injured and can only give rise to other injured
+cells and thus the next generation of offspring are equally weak and
+injured and so on. The only hope for such a line of individuals is that it
+can be crossed by normal stock, in which case the vigor of the normal
+germ-cell in the combination may counteract, or at any rate reduce, the
+extent of injury in the body cells of the resulting animal.&#8221;</p>
+
+<p>He also believes that various deformities and developmental arrests such
+as harelip and cleft-palate may similarly be cases of transmission rather
+than true inheritance, due to the weakening of the germ-cells in some way,
+or to some lack of full vigor in the uterine environment.</p>
+
+<p><b>Further Remarks on the Situation in Man.&mdash;</b>Returning now to the question of
+alcoholism in man, it seems in view of the strong circumstantial evidence
+in the case of man himself, together with the result of<span class="pagenum"><a name="Page_179" id="Page_179">[Pg 179]</a></span> experiments on
+animals, that little doubt remains that excessive alcoholism might result
+in the production of defective offspring. On the other hand an antecedent
+degeneracy or neural instability undoubtedly plays an important part in
+many cases, in the original production of drunkards, and when such occurs,
+it, as well as the direct effects of alcoholic poisoning, must be reckoned
+with in the effects on progeny. Studies carried on by Pearson, Elderton
+and Barrington of the Eugenic Laboratory in London lead these
+investigators to the conclusion that extreme alcoholism is a <i>result</i> not
+a <i>cause</i> of degeneracy. That is, the degeneracy is due to the defective
+stock, not to alcohol. They cite in evidence their records of four
+thousand school children of alcoholic and of sober parents, which fail to
+show any unfavorable effect of alcohol on offspring. Some of their
+critics, however, maintain that they did not choose subjects who were
+sufficiently alcoholic to give the injurious results that might
+legitimately be expected among the offspring of excessive drinkers or
+habitual drunkards.</p>
+
+<p>Where children show a hereditary inclination toward drink, unquestionably
+one of the strongest factors is the inheritance of the same disposition,
+the same unstable nervous constitution and its accompanying lack of
+self-control which led the parent to drink, rather than the inheritance of
+the effects of the drink on the parent. For in many cases a parent may not
+become a drunkard until after the children who also become drunkards are
+born. That the tendency to drink immoderately is frequently due to a
+strain of feeble-mindedness or epilepsy becomes more evident<span class="pagenum"><a name="Page_180" id="Page_180">[Pg 180]</a></span> every day.
+In many of the so-called &#8220;periodical&#8221; drunkards, the accompanying features
+of their periodic attacks of drink-craving, such as clouding of memory,
+restlessness and depression, are those commonly associated with ordinary
+epileptic attacks.</p>
+
+<p><b>Probably Over Fifty Per Cent. of Inebriety in Man Due to Defective Nervous
+Constitution.&mdash;</b>Branthwaite, an English authority on drunkenness, finds
+that about sixty-three per cent. of the inebriates who come to his notice
+are mentally defective. In alcoholic insanities heredity is a potent
+factor. It is coming to be realized more and more that pronounced
+alcoholism is due in a large percentage of cases, perhaps over half, to a
+defective nervous make-up. While it is true that many drunkards would not
+develop without free access to alcohol, on the other hand many would never
+develop without a bad heredity back of them, which gives them a peculiar
+nervous constitution that renders alcohol an undue stimulus. In a recent
+report of the New York State Hospital Commission it is stated that in
+fifty-four per cent. of the cases of alcoholic insanity, a family history
+of insanity, epilepsy or nervous disease exists. Thus in the presence of
+alcohol most of these unfortunates are helpless pawns of a hereditary
+weakness.</p>
+
+<p>So when the question of alcoholism is viewed from all angles, the children
+of the human drunkard would seem to run a double menace of misfortune,
+since they may be subject both to the direct poisoning effects of alcohol
+and the results of an inheritable degeneracy.</p>
+
+<p><b>Factors to Be Reckoned With in the Study of Alcoholism.&mdash;</b>In any
+thoroughgoing study of <span class="pagenum"><a name="Page_181" id="Page_181">[Pg 181]</a></span>alcoholism in man many factors will have to be
+reckoned with. First of all there is the question of inherent lack of
+control. This is probably the principal thing inherited where heredity
+truly enters as a factor. That example and social environment are
+important factors in addition to or in place of heredity is clear, too,
+when we observe that often it is the boys only who take after a drunken
+father, for there is no evidence that the inherited tendency when it
+really exists is at all sex-linked. Again, in certain occupations carried
+on under unwholesome influences relief is frequently sought in alcoholic
+stimulants, and such custom may easily crystallize into habit.
+Furthermore, the accustoming young children to doses of alcohol, or the
+unborn young to alcohol through the body of a drunken mother, may be
+strongly contributory toward establishing inebriety in certain cases. As
+we have seen from an abundance of experimental data on animals, moreover,
+the nurture effects on germ-cells may result in the production of weakened
+offspring. Such offspring in the case of man are probably less able to
+withstand temptations of all kinds and hence readily succumb to the
+habit-forming effects of alcohol if once its use is begun. Lastly, it must
+not be forgotten that alcoholism in the father usually means poverty and
+the subsequent accompaniment of malnutrition and neglect of the children,
+and this in itself may not only account for poor development of the
+latter, but may also be strongly contributory toward establishing the
+habit of alcoholism in them.</p>
+
+<p>An inherent bias plus most of the other conditions<span class="pagenum"><a name="Page_182" id="Page_182">[Pg 182]</a></span> just enumerated is the
+not unusual lot of the offspring of drunkards.</p>
+
+<p><b>Venereal Diseases.&mdash;</b>There is yet another very considerable class of
+maritally unfit who in any conscientious discussion of unfitness for
+marriage or of racial improvement must be considered. I refer to those who
+are afflicted with the diseases which are inseparably associated with the
+so-called &#8220;social evil.&#8221; To <i>gonorrhea</i>, one of the most prevalent of
+these diseases, more than one-fourth of our total one hundred and ten
+thousand blind in the United States are said to owe their affliction.
+Milder types of eye disease may also result from such infections. As much
+as eighty per cent., or some say practically all blindness in children
+born blind is caused by it, the infection occurring at the time of birth
+or within a few days thereafter. The terrible consequences of this disease
+to the innocent wife would alone make its discussion imperative.</p>
+
+<p><b>The Seriousness of the Situation.&mdash;</b>Unfortunately the insidious nature of
+gonorrheal infections is unknown to most persons. A cure is apparently
+effected, yet as a matter of fact the germs may live for years and, if in
+the male, later be transmitted to the wife, subjecting her to a future of
+invalidism and misery. Reliable statistics from various medical
+authorities reveal the appalling fact that seventy-five per cent. or more
+of the surgical operations for inflammatory pelvic disorders peculiar to
+women, such as pus tubes and peritonitis, are attributable to this
+disease, as is also the involuntary sterility of forty-five per cent. of
+childless women. Unwelcome as the fact is there is an abundance of
+evidence to show that a large percentage<span class="pagenum"><a name="Page_183" id="Page_183">[Pg 183]</a></span> of men in particular have at
+some period of their life been infected with venereal disease. Of our
+fourteen million males in the United States under the age of thirty we
+find estimates by some specialists in venereal diseases to the effect that
+five million of them, that is, one out of three, suffer from some one of
+the social diseases or their consequences. Doctor Hugh Cabot, one of the
+chief surgeons of the Massachusetts General Hospital at Boston, a member
+of the faculty of the Harvard Medical School and president of the American
+Association of Genito-Urinary Surgeons, has this to say about the
+situation: &#8220;We have of late years heard much about the frequency and
+serious consequences of tuberculosis; it has been dubbed the &#8216;white
+plague,&#8217; and so active has been the campaign that a wide-spread
+understanding of this serious disease has resulted. It may safely be
+averred that in the urban population at least there are two, and perhaps
+three, individuals with syphilis to every one with tuberculosis. The
+frequency of gonococcus infection is much higher.&#8221; He believes that over
+half the male population acquire a gonococcus infection at some period of
+their career. While as a layman, one can not but feel that a specialist&#8217;s
+estimate may run unduly high because of the fact that he is encountering
+an inordinate proportion of such maladies every day, still such
+specialists are in position to get at the truth as no other person can and
+their calculations are probably not grossly in error. In any event any one
+who has progressed in worldly knowledge beyond the na&iuml;vet&eacute; of a child must
+recognize the appalling prevalence of these maladies.</p>
+
+<p><b>Infantile Blindness.&mdash;</b>So serious has the matter<span class="pagenum"><a name="Page_184" id="Page_184">[Pg 184]</a></span> of infantile blindness
+become that some state boards of health and some city health departments
+supply all physicians and midwives with specially prepared packages
+containing cotton and nitrate of silver solution for preventive or
+curative treatment of the eyes of all new-born children. At the time of
+the first bath each eye is carefully washed with a separate pledget of
+cotton saturated with boric acid solution. Each then receives a drop of
+the silver solution, which is made just strong enough to kill any
+gonococci that might be present without itself inflaming the eye. Water
+used in bathing the baby&#8217;s body of course is not allowed to come in
+contact with its eyes. Such treatment should be given every child no
+matter how unsuspicious the circumstances may be. German authorities who
+have been following this method now for some years assure us that
+nineteen-twentieths of the blindness of infancy can thus be prevented.</p>
+
+<p><b>Syphilis.&mdash;</b>As to <i>syphilis</i>, another and even more terrible of these
+diseases, we have before us the absurd fact that while thousands upon
+thousands of dollars are being spent to establish a rigid inspection and
+preventive measures against the spread of a very similar disease in the
+horse, this malady in man is allowed to pass unchallenged and we are
+confronted by the gruesome certainty that there are hundreds of these
+diseased persons about us to-day who, on their mere affirmation that they
+are unmarried and of age, will be given the right to marry and thus
+produce families of infected children irrevocably doomed to early death or
+to lifelong misery.</p>
+
+<p>While syphilis is most commonly spread through<span class="pagenum"><a name="Page_185" id="Page_185">[Pg 185]</a></span> relations between the
+sexes, it may be acquired in various other ways, as for example, through a
+cut in shaving with the same razor an infected individual has used. It is
+commonly transmitted from parent to child. Practically every prostitute is
+a center of dissemination. Katherine Bement Davis has shown in her studies
+made at the New York State Reformatory for Women that while ordinary
+clinical tests show that apparently only twenty-one per cent. of these
+women are infected with venereal disease, more careful laboratory tests
+showed at least ninety per cent. to be infected.</p>
+
+<p>Syphilis is caused by <i>Treponema pallidum</i>, a small unicellular animal
+parasite. Given access to the blood by any means whatever, possibly even
+through an abrasion in the lip by means of a kiss, it multiplies rapidly
+and any part or organ of the body may be attacked. Usually a small sore
+occurs at the point of entrance to the body, but often it heals up readily
+with little indication of the seriousness of the infection.</p>
+
+<p>The development of the malady is insidious and long continued. As a matter
+of clinical convenience physicians divide its progress into successive
+stages although in reality the transitions are frequently variable and ill
+marked. The symptoms that arise within the first few months or even years
+are readily controlled by appropriate treatment, but to insure a cure
+prolonged and most thoroughgoing treatment is imperative. The symptoms
+disappear so completely after a short period of treatment that it is very
+difficult to persuade the average patient that he is not yet cured. Two
+years at least are none too short a period of <span class="pagenum"><a name="Page_186" id="Page_186">[Pg 186]</a></span>treatment, yet the majority
+of patients, fully convinced that they are merely being exploited by the
+physician as a source of revenue, drift away at the end of a few months.
+As a matter of fact, however, the germs usually persist long after the
+obvious symptoms of the disease have disappeared, and in consequence many
+of the most serious results of syphilis may not manifest themselves for a
+period of perhaps ten, twenty or thirty years.</p>
+
+<p><b>Some of the Effects.&mdash;</b>It is now known that <i>paresis</i>, also termed general
+paralysis or softening of the brain, is probably invariably due to
+syphilis. The work of Flexner and Noguchi on <i>paresis</i> and <i>tabes
+dorsalis</i> show that always in such afflictions the tissues of the central
+nervous system have been invaded by the parasite. The original infection,
+however, may have occurred so long before as to have been almost forgotten
+by the patient. Thus many an apparently robust man is stricken down in the
+prime of life. Earlier and prolonged treatment would in all probability
+have eradicated the germs and thus prevented the mental breakdown, which
+can not be cured by any known treatment. Postmortem examination always
+shows that the <i>Treponema</i> has wrought wide-spread damage in the brain.
+The frequency of paresis may be realized when one learns that in some
+regions it is responsible for about one-fifth of all cases of insanity
+sent to hospitals for the insane. It ranks next to the highest as a cause
+of insanity. Statistics show that in the state of New York more deaths
+result annually from paresis than from smallpox, tetanus, malaria,
+dysentery and rabies all combined.</p>
+
+<p><span class="pagenum"><a name="Page_187" id="Page_187">[Pg 187]</a></span>In some cases the disease attacks the membranes of the brain and the small
+blood vessels giving rise to a still different type of mental disorder.
+Practically all patients with <i>locomotor ataxia</i> owe their condition to an
+antecedent syphilis. Moreover it is one of the important causes of
+<i>arterio-sclerosis</i>, or hardening of the blood vessels, and is also a
+prominent factor in certain forms of heart-disease, as well as by no means
+an unimportant cause of blindness in children.</p>
+
+<p>As to specific cases of the effects of this disease on descendants the
+literature of the subject is crowded full. While it is needless to conduct
+the reader through a chamber of horrors by reviewing clinical cases, it is
+desirable to point out in a general way some of the effects. Doctor George
+H. Kirby, director of Clinical Psychiatry, Manhattan State Hospital, says:</p>
+
+<div class="blockquot"><p>&#8220;We find that when either the father or the mother suffers from
+paresis that many other members of the family may be infected with
+syphilis, and furthermore, we find that a large number of children in
+these families are feeble-minded, nervous, or in other ways abnormal.
+Doctor Plant examined a group of 100 children, the offspring of cases
+of paresis, and found that 45 per cent. were plainly damaged mentally
+or physically, or in both fields; the blood test showed that one-third
+of these 100 children had the syphilitic poison in their systems.</p>
+
+<p>&#8220;Another investigator found in a group of 139 children, the
+descendants of parents who had syphilitic nervous disease, that over
+25 per cent. were definitely feeble-minded or affected with some
+serious nervous disorders.</p>
+
+<p>&#8220;Other studies indicate that there exists a close <span class="pagenum"><a name="Page_188" id="Page_188">[Pg 188]</a></span>relation between
+syphilis and many of the hitherto unexplained cases of
+feeble-mindedness, including idiocy, imbecility, infantile paralysis,
+and some forms of epilepsy. While the question is not yet settled, it
+appears that syphilis is the real cause of many of these cases of
+mental defect in children.&#8221;</p></div>
+
+<p>Still other investigators give details of physical afflictions and
+distortions, of suppressed development, of inordinate percentages of
+stillbirths&mdash;perhaps the most merciful lot for the little victims&mdash;but
+sufficient has been said to indicate the full horror of the situation.</p>
+
+<p>Goddard,<a name='fna_7' id='fna_7' href='#f_7'><small>[7]</small></a> although not minimizing the terrible nature of the disease,
+finds little evidence in his studies that syphilis in parents is a
+specific cause of feeble-mindedness.</p>
+
+<p><b>A Blood Test.&mdash;</b>Fortunately a delicate blood test known as the Wasserman
+test has been discovered by means of which, through an examination of a
+few drops of blood, any trace of syphilitic poison which exists in the
+body may usually be detected. This is true even though the individual may
+at the time show no visible symptoms of syphilis. The test is therefore of
+great value in detecting the latent germs of syphilis in individuals who
+have apparently been cured, and also often in making an early diagnosis of
+paresis. The Wasserman test, however, is reliable only in the hands of a
+skilled operator. It may occasionally give a positive reaction when
+syphilis does not exist and on the contrary a negative when it is present.
+The <i>luetin</i> test is also now applied by some specialists, but<span class="pagenum"><a name="Page_189" id="Page_189">[Pg 189]</a></span> is too new
+a test to have come into general use. It works on the same principle as
+the tuberculin test for tuberculosis. Some army physicians now also give
+what is termed a provocative Wasserman. That is, in a suspicious case
+which gives only negative results by an ordinary Wasserman, they can get,
+if syphilis really exists, a positive reaction after giving small doses of
+potassium iodide or salvarsan.</p>
+
+<p>It should be well understood by every one that syphilis is usually curable
+provided the patient is given modern scientific treatment by a <i>competent</i>
+physician. I emphasize competent because there are so many quacks in this
+field that one undergoing treatment can not be too careful in assuring
+himself of the competency of the physician. In even a case of long
+standing, where the symptoms have been in abeyance for a number of years,
+the disease can be cured provided it has not developed into an active
+cerebro-spinal type, and even the latter can be much benefited by proper
+treatment. The great danger of the cerebro-spinal type is that it will
+result in paresis or locomotor ataxia.</p>
+
+<p>As long as the blood of a patient shows a <i>positive</i> Wasserman reaction,
+marriage should certainly not be consummated. If after a proper course of
+treatment by a well-informed physician, the patient shows a <i>negative</i>
+Wasserman when tested by a competent examiner, he probably would not
+infect his wife or offspring, although prudence would require that he wait
+at least six months or a year before marriage, and marrying then only if
+later tests remain negative.</p>
+
+<p>The only way for a patient to be sure that he is not harboring the
+cerebro-spinal form would be to have a<span class="pagenum"><a name="Page_190" id="Page_190">[Pg 190]</a></span> spinal puncture made and the
+cerebro-spinal fluid examined. While the cerebro-spinal phase often does
+not occur until long after the primary infection, cases are known in which
+it has appeared within a few weeks. Evidence that the central nervous
+system is frequently invaded early in the course of the disease is
+increasing. Marriage of an individual suffering from the cerebro-spinal
+form should not take place, since such a one is almost sure to become a
+burden on the family or the state.</p>
+
+<p><b>Many Syphilitics Are Married.&mdash;</b>It may seem to some that in a treatise on
+being well-born the subject of syphilis might be ignored as not being
+especially pertinent, but the supposition that no considerable percentage
+of syphilitics marry is not borne out by the facts. Seventy-five per cent.
+of men with insanity due to syphilis who are admitted to hospitals are
+married. The insanity in such cases is mainly the result of infections in
+earlier years, often long before marriage. While syphilis, strictly
+speaking, is not inherited, that is, does not become part and parcel of
+the germ-plasm, still the frequency of its direct transmission to
+offspring is so appalling that the outcome, as far as the immediate child
+is concerned, is quite as disastrous as the most thoroughgoing real
+inheritance could be.</p>
+
+<p><b>Why Permit Conditions to Continue as They Are?&mdash;</b>When one faces the easily
+ascertained facts regarding venereal disease, it seems incredible that we,
+an intelligent people, can go on complacently handing our daughters and
+sisters over to the surgeon&#8217;s knife and a life of personal misery, and
+even in not a few instances to become mothers of incurably defective<span class="pagenum"><a name="Page_191" id="Page_191">[Pg 191]</a></span>
+children, yet the dire fact confronts us that we do. We can no longer
+excuse ourselves on the plea of ignorance, for the grisly record may now
+be read in many medical and not a few popular treatises, and we find the
+theme entering even into the modern drama, as witness Brieux&#8217;s <i>Damaged
+Goods</i>. Further indifference to these conditions can only be attributed to
+culpable apathy or prudery.</p>
+
+<p>The extreme dangers to which parents are subjecting their daughters if
+they do not demand a clean bill of health on the part of their prospective
+husbands are obvious. Fathers and mothers perfectly willing to inquire
+into their future son-in-law&#8217;s social connections, his income, securities,
+or business chances become strangely &#8220;modest&#8221; when it comes to determining
+whether he is physically fit for marriage.</p>
+
+<p>One great cause of ignorance in the past was the prudish taboo against
+frank discussions of venereal diseases which has thrown the veil of
+silence about the subject. To-day, however, it is coming to be recognized
+that these maladies are diseases and not a standard of social propriety,
+and that like most other diseases the surest way to secure prevention and
+gradual eradication is through the enlightenment of the public. They are
+prevalent in all classes of society. Moreover, it must not be forgotten
+that there is no form of venereal disease which may not be innocently
+acquired. Even where acquired through transgression of moral law an
+ignorant attitude toward the sexual instinct is often at the bottom of the
+difficulty.</p>
+
+<p><b>Medical Inspection Before Marriage.&mdash;</b>Ante-nuptial medical inspection is
+certainly as necessary to the<span class="pagenum"><a name="Page_192" id="Page_192">[Pg 192]</a></span> welfare of society as the certification of
+age and of the single state now required by law. No one objects to a
+medical examination pertaining to venereal and other diseases when it
+comes to taking out a life insurance policy, and why there should be any
+more objection to it as a preliminary to marriage is a mystery. A few
+states already have compulsory ante-nuptial medical inspection. The laws
+have been enacted too recently to judge adequately of their working. There
+has been much debate in Wisconsin as to whether their law (Chapter 738,
+Laws of 1913), which went into effect January 1, 1914, is constitutional
+and whether it requires a Wasserman test. The Wisconsin law applies to
+males only. The Supreme Court of the state has declared it constitutional
+and that its requirement of &#8220;the application of the recognized clinical
+and laboratory tests of scientific search&#8221; involves only such examination
+as the ordinary licensed physician is equipped to make and can reasonably
+be expected to make for three dollars, the maximum fee specified in the
+law.</p>
+
+<p>A number of the physicians of the state are still dissatisfied with the
+wording, although most do not oppose the principle of the law. Many
+believe that it should apply to the women as well as to the men, and
+others feel that the law should be extended to cover still other kinds of
+marital unfitness. Most of the practitioners with whom I have discussed
+the matter appreciate the motive underlying the law and are endeavoring to
+make it successful.</p>
+
+<p>The general public of the state as a whole seems to be in favor of the
+provision. At least one hears much<span class="pagenum"><a name="Page_193" id="Page_193">[Pg 193]</a></span> favorable comment and little
+dissension among those who understand its purpose. The very controversy
+over it which sprang up after its passage proved to be of great benefit in
+the education of the public regarding the necessity of such measures. Such
+physicians as I have been able to question report that the candidates for
+marriage rarely object to the requirement, but on the contrary strongly
+favor it. Especially where they have suffered from venereal disease
+earlier in life most are eager to know their condition and to have medical
+advice. To my own mind this last fact is the most significant of all, as
+it will give every candidate for marriage a chance to know the truth. Most
+men are not so much brutal or vicious as ignorant in such matters. The
+vast majority of those unfit for marriage as a consequence of venereal
+disease will, when they realize the danger their condition imposes on wife
+and children, take every possible means to put themselves into proper
+condition.</p>
+
+<p>Desirable as the Wasserman test may be, it requires special laboratory
+facilities and equipment as well as a specially trained examiner to make
+it a reliable test. Moreover it can not be given by the general
+practitioner for the very moderate fee that must obtain in a pre-nuptial
+examination compelled by law. If it or the serum test for gonorrhea are to
+be applied then the legislative body of the state will find it necessary
+to establish a special public laboratory or laboratories for their
+application. This, however, is not a matter of particular difficulty and
+would be capital well invested in any state.</p>
+
+<p><b>The Perils of Venereal Disease Must Be <span class="pagenum"><a name="Page_194" id="Page_194">[Pg 194]</a></span>Prevented at Any Cost.&mdash;</b>However,
+no matter what the cost may be to the state, no matter what the exaction
+from the individual, the grave perils of venereal disease to society
+<i>must</i> be prevented. We owe it to the cause of humanity that there be
+fewer victims born into a world of eternal night, that from a parentage of
+polluted blood there spring no longer hosts of children with feeble
+misshapen bodies or with tarnished intellects, death-marked at the door of
+life.</p>
+
+<p><b>Bad Environment Can Wreck Good Germ-Plasm.&mdash;</b>In conclusion it is evident
+from our discussion of prenatal influences that not all of being well-born
+is concerned with heredity in its proper sense, since the unborn young may
+be influenced either directly or indirectly by environmental conditions
+which are in no sense products of heredity, although as far as the
+immediate child is concerned the result may be quite as disastrous where
+the influence is a baneful one. As to the production of beneficial
+prenatal effects, while parents can do nothing toward modifying favorably
+such qualities as are predetermined in their germ-plasm, nevertheless they
+must come to realize that bad environment can wreck good germ-plasm. They
+can see to it that they keep themselves in good physical condition by
+wholesome temperate living, and thereby insure as far as possible healthy
+germ-cells for the conception and good nutrition for the sustenance of
+their progeny. Their one sacred obligation to the immortal germ-plasm of
+which they are the trustees is to see that they hand it on with its
+maximal possibilities undimmed by innutrition, poisons or vice.</p>
+
+
+
+<p>&nbsp;</p><p>&nbsp;</p>
+<hr style="width: 50%;" />
+<p><span class="pagenum"><a name="Page_195" id="Page_195">[Pg 195]</a></span></p>
+<h2><a name="CHAPTER_VII" id="CHAPTER_VII"></a>CHAPTER VII</h2>
+<p class="title">RESPONSIBILITY FOR CONDUCT</p>
+
+
+<p>Since both physical and mental attributes are unquestionably inherited, it
+becomes a matter of importance to inquire into the nature of the entity we
+call personality. To what extent is human conduct a product of parentage?
+Although apparently free agents are we in reality only by infinitely
+subtle indirections making the responses, forming the habits, establishing
+the characters which result merely from the blind impulsions of an
+inherent constitution? If so, who is praiseworthy, who blameworthy? Are
+men</p>
+
+<p class="poem">&#8220;But helpless pieces of the Game He plays<br />
+Upon this chequer-board of Nights and Days.&#8221;</p>
+
+<p><b>All Mental Process Accompanied by Neural Process.&mdash;</b>Whatever the ultimate
+decision of psychologists may be regarding the relation of mind to the
+sensory and nervous mechanism of man it is certain that there is so close
+an association between them that the least alteration in the mechanism
+means a parallel effect in the mind, or in the words of Huxley, &#8220;every
+psychosis is definitely correlated with a neurosis.&#8221; The rind or <i>cortex</i>
+of gray matter which constitutes the surface of the large cerebral
+hemispheres of the<span class="pagenum"><a name="Page_196" id="Page_196">[Pg 196]</a></span> human brain is regarded as the seat of consciousness.
+The development of the mental powers in the infant is dependent on the
+development of the elements of this cortical substance and the waning of
+the mental faculties in old age goes hand in hand with its atrophy.
+Abnormal arrangements, injuries or omissions in it mean mental
+unsoundness. How the activity of the structural mechanism gives a reaction
+in consciousness is not understood, but we know that in the living being
+the two phenomena are inseparably linked. Whether we accept the hypothesis
+that consciousness is an actual product of the structural mechanism or the
+hypothesis that the latter is only an instrument for the manifestations as
+consciousness of an outside force or entity, just as the telegraphic
+instrument manifests the existence of electricity, is neither here nor
+there for our purposes. On either supposition the degree and manner of
+expression are determined by the structure of the mechanism. Our main
+problem is to decide as nearly as possible how much of the mechanism is
+rigidly inherited, how much is at birth largely undestined, so that its
+ultimate outcome is in part a product of the forces which play upon it, or
+in other words of education and training.</p>
+
+<p><b>Gradation in Nervous Response from Lower Organisms to Man.&mdash;</b>To comprehend
+fully the basic nature of human neural responses one must seek the roots
+in the behavior of lower organisms. For there is found in a simpler form
+many of the fundamental activities and the first dim gropings which emerge
+in man as memory, reason and will. As we ascend the scale of animal life
+we find a continuous advance in<span class="pagenum"><a name="Page_197" id="Page_197">[Pg 197]</a></span> neural complexity and nervous response
+that in many respects grades up closely to the human type.</p>
+
+<p>A windmill or a weather-vane points toward the source of the wind,
+obviously not because either exercises any special choice in the matter,
+but because it is constructed on such lines of symmetry that when the wind
+strikes it, if it slants the slightest to left or right, the more exposed
+surface receives the greatest pressure and thus swings the body back into
+the line of least resistance.</p>
+
+<p><b>Behavior of Many Animals Often an Automatic Adjustment to Simple External
+Agents.&mdash;</b>It is a far cry, of course, from the responses of such a machine
+as a windmill to the responses of even the simplest living thing, but in
+spite of the broad gap between the two, there is much reason to believe
+that the behavior of many living organisms is due in a marked degree to
+the directive effects of comparatively simple external factors rather than
+to the complex internal volitions the casual observer is likely to
+attribute to them.</p>
+
+<p><b>Tropisms.&mdash;</b>It is a marked characteristic of all living protoplasm that it
+has the power of responding to external stimuli. This power of response is
+termed <i>excitability</i> or <i>irritability</i>. In describing the motor responses
+of living organisms to stimuli resulting from a change in surroundings the
+term <i>tropism</i> (Gr. <i>Trop&#275;</i>, turning) is frequently used and the kind
+of stimulus is indicated by a prefix. Thus the term phototropism means a
+turning or <i>orientation</i> brought about by means of light. An organism
+which reacts by a movement toward the source of light is said to be
+<i>positively phototropic</i>, one which moves away from it,<span class="pagenum"><a name="Page_198" id="Page_198">[Pg 198]</a></span> <i>negatively
+phototropic</i>. By using such a neutral terminology the physiologist avoids
+implying that necessarily &#8220;likes&#8221; or &#8220;dislikes&#8221; or any other psychic
+reaction enter into the movements.</p>
+
+<p>Several kinds of tropisms are recognized, such as <i>phototropism</i> or
+<i>heliotropism</i>, reaction to light; <i>thermotropism</i>, reaction to heat;
+<i>electrotropism</i> or <i>galvanotropism</i>, to electric current; <i>geotropism</i>,
+to gravity; <i>chemotropism</i>, to a chemical; <i>rheotropism</i>, to current;
+<i>thigmotropism</i> or <i>stereotropism</i>, to contact; and <i>chromotropism</i>, to
+color.</p>
+
+<p><b>Many Animals Show Tropic Responses.&mdash;</b>Many of the lower animals seem to
+have their movements determined more or less mechanically by the action of
+such external factors, some being positively, others negatively responsive
+to a given kind of stimulus, or the same individual may be at one time
+positive, at another negative, according to modifying conditions to be
+mentioned presently.</p>
+
+<p>In plants and in simpler lower animals there is no special nervous system.
+The responses of these organisms depend on the general irritability of
+their constituent protoplasm. In other animals a nervous system is
+developed, crude and diffuse in lower forms, extremely delicate, complex
+and definitely ordered in higher forms. But it should be borne in mind
+that nerve protoplasm possesses only in high degree a capacity for
+irritability, conduction, etc., that is common to all living substance. In
+keeping with other &#8220;physiological divisions of labor&#8221; or specialization
+which mark the increasing complexity of animals, this enormously enhanced
+sensitivity and conductivity of <span class="pagenum"><a name="Page_199" id="Page_199">[Pg 199]</a></span>certain tissues have come about, and they
+have become set apart for these special functions. In higher animals,
+therefore, the tropisms where operative must act more or less through the
+agency of the nervous system instead of directly through the general
+protoplasm of the organism.</p>
+
+<p><b>Certain Apparently Complex Volitions Probably Only Tropisms.&mdash;</b>Where
+nervous systems enter into tropic responses there must be specific
+sensibility of certain nerve terminations (i. e., sense organs) at the
+surface of the body. These sensory or receiving nerves connect through the
+central system with corresponding motor nerves which in turn supply
+certain specific muscles through the contraction of which the organism is
+as surely and as mechanically oriented as in the simpler cases. For
+example, if light is the stimulating agent, when it strikes a positively
+phototropic animal, if the latter is not already oriented, the eyes or
+other nerve terminations sensitive to light transmit an impulse through
+the central nervous system to certain muscles causing them to increase
+their tension and thereby swing the animal around with its head toward the
+light. Progressive movements which the organism then makes must carry it
+toward the source of light. Thus it is not &#8220;love of light&#8221; that draws the
+moth into the flame but the mechanical steering of the body toward the
+source of light through the stimulations produced by the light waves. It
+is chemotropism, not solicitude for its offspring, which drives the flesh
+fly to lay its eggs on decaying meat. And it is stereotropism and not a
+desire for concealment which impels certain animals such as many worms
+and<span class="pagenum"><a name="Page_200" id="Page_200">[Pg 200]</a></span> insects to get into a close contact with solid bodies, or in other
+words to &#8220;hide&#8221; themselves in burrows and crevices.</p>
+
+<p><b>Complicating Factors.&mdash;</b>However, beautifully as these theories of tropisms
+work out in a broad general way, there are various additional factors
+entering which must be reckoned with, and these become more numerous and
+of more consequence as the organism becomes more complex. In the first
+place certain internal conditions must be considered. Living matter is
+characterized by its instability. There are continual synthetic and
+disruptive processes in progress which the physiologist terms metabolic
+changes. The very &#8220;life&#8221; of such matter seems to be the manifestation of
+such changes. Concerning what the ultimate source of these changes is,
+whether or not indirectly they may be referred to external conditions as
+seems probable to many biologists, no one so far has ever given a
+convincing, positive answer. It is sufficient for our purposes to know
+that they may have set up certain internal stimuli which may modify the
+behavior of the organism in which they reside, and that the &#8220;physiological
+state&#8221; of the organism at the time of external or internal stimulation
+will condition the response. This physiological condition may be dependent
+on the general metabolic equilibrium of the animal, or on the extent of
+previous stimulation by means of the same or different agents. Thus the
+organism may not always react in the same way to the same stimulus.</p>
+
+<p>The intensity of the stimulation and change in the intensity of the
+stimulation, are also factors to be<span class="pagenum"><a name="Page_201" id="Page_201">[Pg 201]</a></span> reckoned with. Moreover, it must be
+taken into account that a given organism is often operating under the
+control of more than one external influence. For example, swarm spores in
+a dish of water which at a given temperature are positively phototropic,
+that is, gather at the side of the dish toward the light, may, if the
+temperature of the water is raised or in case of marine forms if the
+salinity is increased, become negatively phototropic. Sometimes two or
+more forms of stimuli may cooperate in bringing about certain behavior as,
+for instance, in the reaction of the earthworm to a suitable habitat,
+through a combination of chemical and contact stimuli. On the other hand,
+two different stimuli may interfere with each other; for example, the
+usual phototropic responses of certain animals do not manifest themselves
+when they are mating or feeding. In short, anything that alters the
+physiological state of the organism may cause it to react in a different
+manner. And thus with the interplay of shifting external agents and
+variable internal state the bounds of behavior on these purely mechanical
+bases become considerably extended.</p>
+
+<p><b>Many Tropic Responses Apparently Purposeful.&mdash;</b>The query arises as to why
+if these responses are mechanical they are so often apparently purposive;
+that is, why do they so often subserve some useful end for the animal?
+While they do not always work out to the animal&#8217;s benefit, as for instance
+in the case of the moth and the light or under many other conditions that
+can be devised experimentally, as a matter of fact under normal natural
+conditions they are on the whole<span class="pagenum"><a name="Page_202" id="Page_202">[Pg 202]</a></span> useful to the organism, carrying it
+into suitable surroundings of food, lessened danger, temperature, and the
+like.</p>
+
+<p>The probabilities are that in their first origin the reactions were not
+purposive. However, if any proved harmful they would result in the
+extermination of their possessors and hence of that particular strain of
+individuals. Those types that happened to have useful reactions would be
+left and in course of time as the process of eliminating the others went
+on, would become the prevailing types. Any organism which the useful
+reaction had preserved would tend to hand it down to the succeeding
+generation where again it would be the conserver of those individuals
+which possessed it in sufficient degree.</p>
+
+<p><b>Authorities Not Agreed on Details of Tropic Responses.&mdash;</b>Although all the
+foremost modern students of animal behavior accept as facts the more or
+less mechanical orienting effects of external stimuli, there is by no
+means unanimity of opinion regarding details. Some stress as the directive
+factor the continuous action of the stimulating agent on sensitive tissues
+symmetrically situated. Others would maintain that it is the time rate of
+change in the intensity of the stimulating agent, or that the factor is
+different in different cases. Some make much of an automatic sort of
+&#8220;trial and error&#8221; system by which certain organisms test out an inimical
+environment until the path of least irritation is hit upon as the way to
+safety. The field is a broad one and to get at the finer shades of
+distinction the reader will have to refer to<span class="pagenum"><a name="Page_203" id="Page_203">[Pg 203]</a></span> the works of such
+authorities as Loeb, Jennings, Holmes and Mast.</p>
+
+<p><b>Tropisms Grade Into Reflex Actions and Instincts.&mdash;</b>The tropisms in many
+cases become indistinguishable from <i>reflex actions</i> and these in turn
+grade up into the <i>instincts</i> of animals. The latter may be looked on as
+but subtler and more involved reactions made possible through a more
+intricate structural organization. As might be expected of instincts, the
+feature of utility is more in evidence than in simpler tropisms because
+they have become of proportionately greater magnitude, but the same
+fundamental mechanism is apparently at bottom of both. It has already been
+seen how the &#8220;instinct&#8221; of the blow-fly to lay its egg on meat is
+interpretable as a chemotropic response. Thus no elaborate psychic
+mechanism is necessary in such behavior.</p>
+
+<p><b>Instincts.&mdash;</b>In the typical instinct there is a series of &#8220;chain reflexes&#8221;
+in which one step determines the next until mechanically the whole gamut
+of changes is run to the last step. It is characteristic of a purely
+instinctive act that an animal performs it without practise, without
+instruction, and without reason. Moreover, all of the same kind of animals
+tend to perform the act in the same way. But with instincts, as with
+tropisms, the physiological state of the organism must be regarded. For
+instance, the instinctive reactions of an animal sated with food or hungry
+will be different.</p>
+
+<p><b>Adjustability of Instincts Opens the Way for Intelligent Behavior.&mdash;</b>As we
+progress in the scale of<span class="pagenum"><a name="Page_204" id="Page_204">[Pg 204]</a></span> animal life this adjustability of instincts to
+new conditions comes more into evidence. While prescribed in the main by
+internal impulse the carrying out of the action is capable of some
+adaptability to circumstances. And in proportion as this adaptability
+releases the organism from a blind rigid working-out of a predetermined
+end, there is opened up the possibility of intelligent behavior; that is,
+of modification of the instinctive behavior by individually acquired
+experience.</p>
+
+<p>While the generation of instinctive impulses still occurs it is left more
+for individual experience to teach discrimination between ends. But we can
+not escape a fundamental structural mechanism, for with this new capacity
+of educability must come new structural mechanisms in the nervous system
+and this must be as faithfully reproduced in each individual as is the
+basis for any other nervous response. How low in the scale of animal life
+animals can profit from their experiences to the extent that their future
+conduct is conditioned thereby is not known. Some would place it as far
+back as the protozoa, others would not. Where such modification of
+behavior is possible there must be some mechanism for the storage of
+impressions in the form of what we term <i>memory</i>.</p>
+
+<p><b>Modification of Habits Possible in Lower Animals.&mdash;</b>Among invertebrates
+such animals as crayfish will acquire new habits, or rather will modify
+old ones. Even as lowly an organism as the starfish can have changes of
+habit thrust on it. When a starfish is placed upon its back it rights
+itself by means of its arms or rays. Professor Jennings found that in a<span class="pagenum"><a name="Page_205" id="Page_205">[Pg 205]</a></span>
+given individual the tendency was always to employ certain rays for this
+rather than others. However, by preventing the use of the rays customarily
+employed, he found that the animal would use a different pair and that
+ultimately in this way it could be trained into the habit of using this
+pair of rays even when restrained in no way. One starfish which was given
+one hundred eighty such lessons in eighteen days after an interval of
+seven days still retained the new habit; young individuals were found to
+be more easily trained than old ones.</p>
+
+<p><b>Some Lower Vertebrates Profit by Experience.&mdash;</b>Among vertebrates it is
+known that those as low in organization as fish will profit by experience.
+They will learn to come for food at a regular time and apparently learn
+more or less to appreciate the presence of certain obstacles with which
+they have had unsatisfactory experiences. Professor Sanford sums up what
+he believes are the limitations of the piscine mental organization as
+follows: &#8220;No fish is ever conscious of himself; he never thinks of himself
+as doing this or that, or feeling in this way or that way. The whole
+direction of the mind is outward. He has no language and so can not think
+in verbal terms; he never names anything; he never talks to himself; as
+Huxley says of the crayfish, he &#8216;has nothing to say to himself or any one
+else.&#8217; He does not reflect; he makes no generalizations. All his thinking
+is in the present and in concrete terms. He has no voluntary attention, no
+volition in the true sense, no self-control.&#8221;</p>
+
+<p><b>Rational Behavior.&mdash;</b>Finally, however, out of these first dull glimmerings
+of intelligence as exemplified<span class="pagenum"><a name="Page_206" id="Page_206">[Pg 206]</a></span> in the higher invertebrates and the lower
+vertebrates, which can modify behavior as the result of experience, come
+the still higher factors so dominant in man, of <i>rational</i> behavior. This
+higher mental process can realize the end to be reached and can deliberate
+on the means to be employed. By means of his <i>reason</i> man can overcome
+difficulties in advance by &#8220;thinking&#8221; out suitable schemes of action. Some
+naturalists believe that man stands alone in possessing the power to
+reason, although others believe that some of the other mammals, notably
+the other primates, possess the same attribute although in a much less
+degree.</p>
+
+<p><b>Conceptual Thought Probably an Outgrowth of Simpler Psychic States.&mdash;</b>Is
+the capacity for such conceptual thought, however, which appears as the
+final efflorescence of complex neural activity something entirely new?
+Most students of comparative psychology maintain that it is not. Just as
+one kind of an instinct frequently grows out of another, so has this grown
+out of the complex of <i>psychic</i> states which preceded it. It apparently is
+the product of the increasing awareness on the part of animals of their
+neural processes and the outcome of these processes, which becomes more
+and more prominent as we ascend the scale of animal life. With the advent
+of associative memory the mind comes more and more to deal with attributes
+of objects instead of merely with each single concrete object as it
+presents itself, and these attributes being common to many objects, come
+to represent definite ideas which can be manipulated by the mind.
+Language, of course, has been an <span class="pagenum"><a name="Page_207" id="Page_207">[Pg 207]</a></span>indispensable aid to man in this regard,
+for words become descriptions of facts and symbols of concepts, and
+thereby allow of abstract thought.</p>
+
+<p><b>The Capacity for Alternative Action in High Animals Renders Possible More
+Than One Form of Behavior.&mdash;</b>With this modification of instinct by
+experience made possible, there comes at the same time, of course, the
+capacity for a rational instead of a purely instinctive behavior. This
+very capacity for alternative action opens up many new possibilities of
+behavior and together with the well-known fixative effects of habit, also
+the opportunity of permanently establishing certain ones. Thus it is
+obvious that a behavior toward which in a strict sense there can not be
+said to have been an original specific tendency, can be developed. What
+was present in the first place was only a general possibility of the
+development of any one of several types of behavior. The final choice of
+the alternatives together with repetition makes it the habitual behavior
+of the individual. Of course it can be urged that if the selection of the
+type of behavior is left to the individual then the latter will operate
+automatically toward the various impulsions of its neural make-up and one
+path will be followed because of stronger inclination in that direction,
+so that the whole procedure is in the end the mere operation of an
+automaton. But however this may be in the individual left to itself, the
+fact is in man that the young individual is never left to itself and in
+the nature of things can not be, so that without entering into this
+troubled pool of controversy regarding freedom of the will, I wish merely
+to point out that the possibility<span class="pagenum"><a name="Page_208" id="Page_208">[Pg 208]</a></span> of more than one form of behavior
+exists and that if one is more desirable than the others then this one can
+be chosen by the ones responsible for the training of the young individual
+and clenched fast by the agency of habit.</p>
+
+<p>Intelligence, reason and habits, however, no less than instincts and
+tropism must have neural as well as psychical existence and we can not
+escape therefore the underlying mechanism.</p>
+
+<p><b>The Elemental Units of the Nervous System Are the Same in Lower and Higher
+Animals.&mdash;</b>It is interesting to note that the fundamental neural mechanism
+which underlies the mental processes of higher animals is not essentially
+different from that which serves in lower forms. Although as animals
+become more complex their nervous systems have become proportionately
+larger and incomparably more intricate, still all the changes have been
+rung on the same basic neural unit, the <i>neuron</i> or nerve-cell (Fig.
+32<i>A</i>, <a href="#Page_209">p. 209</a>). The higher nervous system differs from the lower in the
+number, in the specializations and in the associations of these units
+rather than in possessing something of entirely different elemental
+structure.</p>
+
+<p><b>Neuron Theory.&mdash;</b>According to the prevailing modern conception the entire
+nervous system is made up of a series of units called <i>neurons</i>. Each
+neuron is a single cell with all its processes. The latter consists
+typically of short branching processes on the one hand, known as
+<i>dendrites</i>, and of a single process on the other, known as the <i>axon</i>,
+which extends from the cell to become a nerve fiber (Fig. 32, <a href="#Page_209">p. 209</a>). The
+various neurons, with possibly a few exceptions, are not <span class="pagenum"><a name="Page_209" id="Page_209">[Pg 209]</a></span>anatomically
+continuous but contiguous. They communicate with one another apparently by
+contact only. The axon of each neuron ends in an elaborate series of fine
+branchings which lie in contact with the dendrites of another neuron, or
+in some cases with the body of the other cell (Fig. 32, <a href="#Page_209">p. 209</a>). Thus the
+nervous impulse passes from one neuron to the other at these points of
+contact. An impulse is supposed to travel normally only in one direction
+through a neuron, the dendrites being the receiving and the axon the
+discharging terminals. There are various types of neurons. Some,
+particularly within the brain, have their main processes so provided with
+branches and brushes that they may come into physiological connection with
+a number of other neurons.</p>
+
+<p>&nbsp;</p>
+<div class="figcenter"><img src="images/img30.jpg" alt="" /></div>
+<p class="center"><span class="smcap">Fig. 32</span></p>
+
+<p class="descrip">A&mdash;Diagram to illustrate neurons and their method of connection; <i>a</i>,
+axon; <i>d</i>, dendrite; <i>s</i>, synapse. To simplify the diagram the medullary
+sheathes of such fibers as would have them have been omitted. The arrows
+indicate the direction in which the impulse travels. The lower series
+shows diagrammatically how from the same neuron in the cortex two
+subordinate neurons may be affected, the one excited to cause contraction
+of a certain group of muscle fibers, the other inhibited so that the
+antagonistic fibers may relax and thus not hinder the movement of a given
+part.</p>
+
+<p class="descrip">B&mdash;Section of a region of the cerebral cortex (after Cajal). The cells
+have been blackened with chrome-silver and are much less highly magnified
+than the diagrams in A. The numerals refer to certain characteristic
+layers of the cortex in this region.</p>
+<p>&nbsp;</p>
+
+<p><span class="pagenum"><a name="Page_210" id="Page_210">[Pg 210]</a></span><b>Establishment of Pathways Through the Nervous System.&mdash;</b>It is believed that
+more or less resistance to transmission of stimuli prevails at the point
+of contact (<i>synapse</i>) between two neurons but that this resistance is
+lessened by repetition of conduction. The frequent traversing of a given
+pathway by similar impulses finally results in an automatic occurrence of
+the transmission, or, in other words, the action becomes habitual.
+Education consists largely in establishing such routes through the nervous
+tissue. Because of the greater plasticity of the neural mechanism in youth
+it is easier to open up and fix pathways of conduction than in later
+years. Moreover the earlier established lines of conduction become the
+more permanent.</p>
+
+<p><b>Characteristic Arrangements of Nerve Cells Are as Subject to Inheritance
+as Other Structures of the Body.&mdash;</b>That the main features of the nervous
+system<span class="pagenum"><a name="Page_211" id="Page_211">[Pg 211]</a></span> are inherited becomes obvious when we see that each kind of animal
+has its own distinctive numbers, arrangements and proportions of the
+various neural units. In man, for example, there are certain
+characteristics, types and groupings of nerve-cells which are reproduced
+generation after generation with remarkable fidelity. This means that in
+so far as these represent the mental make-up of the individual, his
+mentality is continuously linked with others which have gone before. The
+new-born child has all the nerve-cells in its brain that it will ever have
+but the ultimate linkages of the finer connectives between them, or at
+least the pathways of travel, remain in large measure to be made.</p>
+
+<p>As we have already seen, the cerebral cortex is the seat of the chief
+mental faculties of man or at least of the highest of these. Professor
+Lloyd Morgan, one of our greatest authorities on comparative psychology,
+is inclined to believe that the instincts are located in the subcortical
+material. In any event, the inheritance of mental ability resolves itself
+into the inheritance of a certain cerebral mechanism.</p>
+
+<p><b>Different Parts of the Cortex Yield Different Reactions.&mdash;</b>The cerebral
+cortex, however, is not functionally homogeneous throughout. Certain
+regions have been shown to be motor, others sensory, and moreover, these
+regions are apparently further specialized so that a given one of them is
+associated with a specific type of sensory or motor response, not merely
+with responses in general. Thus by injuring one of the sensory areas we
+might destroy vision but not other sensations, or by stimulating one of
+the motor<span class="pagenum"><a name="Page_212" id="Page_212">[Pg 212]</a></span> centers we would get a response in a corresponding motor organ
+but not in all such organs. Likewise, it is probable that still different
+areas, the so-called &#8220;association areas,&#8221; relatively of much greater
+development in man than in any other animal, are the regions in which
+various perceptions and conceptions are synthesized and formed into
+organized knowledge. Here also are engendered the volitions which when
+flashed through the motor centers become expressed in activity or
+behavior.</p>
+
+<p>It seems highly probable that just as the sensory and motor areas differ
+in kind from one another, so we must suppose there are qualitative
+differences in various parts of the association areas so that the
+different parts give different reactions in consciousness; that is, each
+special mental ability of the individual is more or less centered in a
+special part of the cortex. And just as there may be variations in other
+structures of the organism so there may be variations in these areas. The
+&#8220;gifted&#8221; person in some one direction, whether it be in mathematics,
+music, painting, or what not, is on this hypothesis one who has that
+particular area of his brain which forms the basis for the talent in
+question more highly developed than it is in the average individual. And
+since such talents are handed down to descendants, this can only mean that
+a similar grouping of the neurons in the region in question has occurred.</p>
+
+<p><b>Skill Acquired in One Special Branch of Learning Probably Not Transferred
+to Another Branch.&mdash;</b>Such a differential arrangement of the brain-mechanism
+which presumably underlies the various mental<span class="pagenum"><a name="Page_213" id="Page_213">[Pg 213]</a></span> abilities would lead to the
+inference that skill in one special branch of learning, in so far as it
+involves only certain centers of the cortex, would not be transferred to
+another branch based on different neural pathways and centers. Development
+of historical knowledge, for example, would not enhance one&#8217;s mathematical
+ability, or vice versa. The testimony of various psychologists bears out
+this idea. In so far as certain factors of training, such as habits of
+industry, concentration, etc., are common to the study of either
+mathematics or history, the good effects of either discipline will
+probably be much the same, but the identity of effect vanishes as soon as
+the intrinsic characteristics of the subjects themselves are involved.</p>
+
+<p>Just how far we are warranted, however, in carrying this idea of localized
+functions as regards the association areas is a moot question. Our present
+attitude regarding the specificity of such localizations is largely a
+matter of inference based on analogy to conditions which obtain in other
+and better known parts of the brain, together with the indubitable
+differences in inborn abilities which exist between individuals. Some few
+brain physiologists maintain that the whole cortex operates more or less
+as a unit in all of the higher psychical activities.</p>
+
+<p><b>Preponderance of Cortex in Highest Animals.&mdash;</b>One of the most interesting
+conditions in the nervous system of the highest types of animals is the
+way in which the cortex has outrun the other parts of the brain in size
+and complexity and has come to dominate the organism more and more both
+directly and indirectly. Aside from the proportionately greater <span class="pagenum"><a name="Page_214" id="Page_214">[Pg 214]</a></span>increase
+in size of the cortex, there is an abundance of anatomical evidence of
+this altered and probably altering system of control in man and the higher
+apes. This is well illustrated in the fiber tracts (nerve bundles) of the
+spinal cord.</p>
+
+<p><b>More Long Fiber Tracts in the Spinal Cord of Man.&mdash;</b>The spinal cord
+although having many nerve centers of its own is also in great part a
+large cable for conducting enormous numbers of fibers from one part of the
+cord to another, or to and from the brain. In man and the higher apes a
+considerably larger percentage of the total area of the cord is given up
+to the long fiber tracts from the brain to the body than in lower
+vertebrates. This progressive increase in long fiber tracts in the higher
+anthropoids probably marks more and more domination of the body by the
+higher brain centers and correspondingly less by the direct activity of
+the cord and by the lower brain centers. However, even in man, many of the
+simpler reflexes of the body still have their centers in the spinal cord.</p>
+
+<p><b>Special Fiber Tracts in the Cord of Man and Higher Apes.&mdash;</b>There are
+certain special tracts of the cord that are particularly interesting in
+connection with the increasing domination of the brain over the body,
+namely, the <i>pyramidal tracts</i>. These were the latest tracts to appear in
+the animal kingdom and are apparently the latest to become functional in
+the individual. It is believed that the development of the medullary
+substance (an enveloping sheath) of the common medullated nerve fiber
+marks the time of entrance of the fiber into activity and it is a
+significant fact that the formation of this sheath occurs last of<span class="pagenum"><a name="Page_215" id="Page_215">[Pg 215]</a></span> all in
+the fibers of the pyramidal tracts, where it does not appear till after
+birth. These tracts convey impulses from the brain to the body. They
+consist of two sets of tracts, in fact, one the crossed, the other the
+direct. As an anomaly, probably arising most frequently from instrumental
+injury at birth, the pyramidal tracts fail to develop normally, with the
+distressing result that the infant, although possessing perfectly normal
+brain activity and normal spinal cord reflexes, is unable to exercise
+voluntary control of the body. In other words the condition, like
+hare-lip, is one of suppressed development. At least this seems to be the
+most plausible explanation of what is known as <i>Little&#8217;s disease</i>. Such
+unfortunates usually die early although they may survive for a few years.</p>
+
+<p>The direct pyramidal tracts occur only in man and man-like apes. They vary
+considerably in extent in different individuals. They originate in nests
+of characteristic large cells located in the cerebral cortex and are
+regarded as paths, though not the only ones, through which volitional
+impulses are conveyed from the brain. They seem to control certain of the
+finer and more delicate movements of the body.</p>
+
+<p><b>Great Complexity in Associations and More Neurons in the Brain of Man Than
+of Other Animals.&mdash;</b>It has already been noted that as animals stand higher
+in the scale of life while the general plan of their neural elements
+remain the same, there is increasing complexity in the number and
+connections of the neurons. The number of processes on individual
+nerve-cells is also greater. There is in fact much greater complexity in
+the number of processes and the <span class="pagenum"><a name="Page_216" id="Page_216">[Pg 216]</a></span>inter-connections of the neural cells
+than in the numbers of the cells themselves. This would seem to indicate
+that the greater mental activities of higher animals depend more on
+richness in complex associations than on mere increase in number of
+neurons. The latter, however, is by no means unimportant as may be seen in
+man, for instance, in whom it is estimated that the cerebral cortex, that
+is, that part of his brain in which his more complex mental processes
+transpire, contains some nine billion more nerve cells than does the
+corresponding region of the brain of an anthropoid ape.</p>
+
+<p>Of especial significance in the psychic make-up of man is his vastly
+increased capacity for inhibition. Although not possessed by all men in
+equal measure and not entirely wanting in lower animals it is a
+distinctive feature in all human conduct. Much of any child&#8217;s education,
+particularly as it pertains to behavior, must be concerned with training
+in the exercise of proper inhibitions. He must learn to suppress certain
+primitive types of reaction in favor of higher ones. This applies not only
+to motor activities but to trains of thought as well. The essence of
+self-control consists mainly in ability to substitute for one impulse or
+idea other compensating ones. And the secret of concentration lies in
+being able to banish irrelevant ideas and focus on the central thought.</p>
+
+<p><b>The Nervous System in the Main Already Staged at the Time of Birth for the
+Part It Must Play.&mdash;</b>It is clear from what is known of its anatomy that in
+the main the central nervous system is framed to respond in certain set
+ways, that there are determinative elements in it which control or
+determine the responses,<span class="pagenum"><a name="Page_217" id="Page_217">[Pg 217]</a></span> and therefore the behavior of the body. The same
+evidence shows also, however, in the incompleteness of many of the
+associations, that while the stage is all set and some of the main
+features of the performance are determined at the time of birth,
+considerable yet remains to be done toward fitting the parts together and
+working up the detail. Just exactly what and how much is rigidly
+determined no one knows.</p>
+
+<p><b>Many Pathways of Conduction Not Established at Birth.&mdash;</b>As we have already
+seen the evidence is that many of the neural pathways are not yet fully
+established at birth, and there is some indication that routes once opened
+may be altered. To what degree this has bearing on behavior is still
+unknown, but since neurologists attribute so much importance to the
+richness and the associations of the cell-outgrowths, it is evident that
+this increase in the number of pathways after birth with possible
+alternatives of connections may be a very important factor in the
+modification of behavior. Yet, on the other hand, we are completely in the
+dark as to what extent these later associations are predetermined in the
+earlier cells.</p>
+
+<p><b>The Extent of the Zone That Can Be Modified Is Unknown.&mdash;</b>There is little
+doubt that many of the paths of action are already firmly established.
+Others, although not irrevocably fixed, offer the least resistance and
+would &#8220;naturally&#8221; be taken if not counteracted or modified by the more or
+less artificial development and fixation of other paths through
+cultivation and habit. Yet others perhaps are largely neutral; they still
+await the initial decisive push which &#8220;choice&#8221; or external environment may
+mete out to them. As<span class="pagenum"><a name="Page_218" id="Page_218">[Pg 218]</a></span> trainers of youth all that is left that we can do is
+to attempt to develop in certain ways the elements of this indefinite,
+impressible zone. Unfortunately, we must labor in the dark to a great
+extent as we have all too little indication of which the malleable factors
+of intellect and conduct are. We can only infer from long, intelligent and
+sympathetic observation of children in successive stages of their
+development. It is only by having clearly in mind the nature of our
+problem that our conclusions will finally come to be of enhanced practical
+value in the training of children. Observation to the present time clearly
+indicates that many children are strongly predisposed this way or that &#8220;as
+the sparks fly upward.&#8221;</p>
+
+<p>This is a point too frequently overlooked by educators. They are often
+unduly actuated by the other piece of the truth that, &#8220;as the twig is bent
+the tree inclines.&#8221; They sometimes fail to realize that after all the tree
+remains the same kind of a tree. If an apple tree, while it may be bent
+from the normal path of development, it can not produce other fruit than
+apples. Just how much the destiny of man can be influenced by training and
+the exercise of his own will power is the fundamental question not only of
+pedagogy but of ethics as well. For if man&#8217;s rational judgments are
+markedly conditioned by his neural make-up then the volitional judgments
+which underlie conduct are likewise conditioned since they are
+inextricably intermingled with his reason. We must believe that to a
+considerable extent emotional expression, as well as other mental
+functions, is due to <span class="pagenum"><a name="Page_219" id="Page_219">[Pg 219]</a></span>hereditary dispositions of the neurons in the
+various parts of the brain.</p>
+
+<p><b>Various Possibilities of Reaction in the Child.&mdash;</b>Despite the innate
+predeterminations of the tree, it is nevertheless our province to see that
+the twig <i>is</i> bent, but our work can only be done with due intelligence
+when we recognize something of the limitations of our material. Of the
+various possibilities of reaction we must see that certain desirable ones
+are realized, even, in some cases, if only to have others thereby
+excluded. It is a commonplace of psychology that all cerebral excitations,
+no matter what the origin, must vent themselves in some way and if this
+expression is not directed into proper channels it will very likely find
+improper ones. We must see that the young wearer of the coat of
+undetermined capacities gets it set by repeated performance into the
+habitual wrinkles of normal social conduct. For it is a trite observation
+that when habits are once well established it requires tremendous efforts
+to do otherwise than as they dictate. There is not the least doubt that
+some of our subjects will respond much more readily to training in certain
+directions of habitual reactions than others, but we have always the
+consolatory knowledge that no matter how difficult the art may be at
+first, repetition reduces the difficulty.</p>
+
+<p>While much of any youth&#8217;s character must be determined by external forces
+brought to bear upon it, the ultimate climax of our effort and measure of
+our success will be the extent to which we have engendered in him the
+capacity for initiating and carrying out<span class="pagenum"><a name="Page_220" id="Page_220">[Pg 220]</a></span> through his own volition those
+impulsions and inhibitions which tend to the highest good of humanity.</p>
+
+<p><b>Probable Origin of Altruistic Human Conduct.&mdash;</b>Those phases of human
+conduct which find expression in consideration for others seem no less
+than other mental attributes to have their origin in certain fundamental
+instincts. Altruistic conduct, in last analysis, apparently resolves
+itself back largely to certain very fundamental impulsions, namely those
+which arise out of certain obligations for the welfare of others which are
+necessarily associated with the marital, parental and filial relations
+that must exist where the young require post-natal care. Looked at from
+the standpoint of natural selection, this would come about as a mere
+matter of survival value. Where the young, as in man, are helpless for a
+long period of time, more opportunity would be afforded for the
+development of both conjugal and filial affection. The sympathetic
+emotions once established in such family relations would partly through
+habit, partly through community of interest, readily become extended to
+clan or tribe and as a final consummation to all mankind.</p>
+
+<p><b>Training in Motive Necessary.&mdash;</b>In the training of children, then, we must
+recognize first of all that there are decided inclinations or bents which,
+as long as they are not anti-social in nature, must be respected if not
+always encouraged. While it is necessary to utilize these as much as
+possible in their training still we must bear in mind that although it is
+natural for a child to follow certain interests, the fact remains that as
+regards social worth these natural interests may not be the most valuable.
+When this is true we must strive<span class="pagenum"><a name="Page_221" id="Page_221">[Pg 221]</a></span> to develop others which will compel
+attention and thus become impelling factors in conduct. Where certain
+fundamental impulsions run contrary to the common welfare it is necessary
+to practise the child in the setting up of inhibitions or counter-impulses
+until this becomes habitual. He must be led to construct a protective
+mantle of appropriate scruples, doubts and fears. It is all important to
+get the proper motives for action to prevail in his mind.</p>
+
+<p><b>Actual Practise in Carrying Out Projects Is All Important.&mdash;</b>But on the
+other hand it is equally important to see that the action is effectively
+carried out. In the matter of self-discipline, particularly, we may have
+many ideal impulses and realize that they should prevail over certain of
+our natural propensities, but unless we put forth effort to overcome the
+propensities our ideal impulses are of no avail. The world has many such
+moral paralytics to-day who can not seize their &#8220;languor as it were a
+curling snake and cast it off.&#8221; It is training in this very overcoming of
+reluctance, in this putting forth of actual effort toward worthy ends
+instead of merely memorizing precepts about the desirability of such
+accomplishments, that is so sadly lacking in our school and home life
+to-day. We prate of the importance of self-control, we say with our lips
+that the way to learn to do is by doing, we proclaim that it is more vital
+to instil good mental and physical habits into our pupils than to stock
+them with information, we preach that mere fact training is as conducive
+to making a first-class rascal as an upright man, yet we jog on
+complacently in the well-beaten ruts of memory routine which require the
+memorizing<span class="pagenum"><a name="Page_222" id="Page_222">[Pg 222]</a></span> of symbols rather than real understanding. We seldom require
+that our prot&eacute;g&eacute;s make intelligent judgments based on evidence, we rarely
+exact of them decisions in matters of ethics, and almost never demand that
+they put their knowledge into efficient accomplishment. It can not be too
+strongly urged that we need less of formul&aelig; learned by heart, less dead
+erudition pigeonholed in the brain like so many foreign bodies, and vastly
+more assimilation of knowledge into the living personality of the
+individual.</p>
+
+<p>Where in school or home to-day do we find provision for such training? Our
+tendency is, in fact, just the opposite. According to the modern code, as
+it works out in many instances at least, the child must be taught through
+play. Though it is a truism that he who has not learned obedience can
+never be master of himself, the child of to-day must not be made to obey
+but be wheedled into changing his mind. If a given subject of study proves
+distasteful to him, the fault is the teacher&#8217;s for not making it
+interesting, for he must always be led on by the thrill of fascination. In
+other words, the child must not only be allowed but be encouraged to take
+the path of least resistance. His own pleasure is to be the standard of
+his actions. Let no stern demands of duty interfere!</p>
+
+<p>Is it any wonder that the products of such tutelage come into the
+activities of life self-indulgent and undisciplined, and although often
+recognizing our private and public shame in business, politics and
+conduct, still remain supine, evasive of the unpleasantness or hardships
+of reform, or inefficient or unwilling in accomplishing unselfish ends?</p>
+
+<p><span class="pagenum"><a name="Page_223" id="Page_223">[Pg 223]</a></span><b>Interest and Difficulty Both Essential.&mdash;</b>The writer does not wish to be
+understood as minimizing the importance of interest on the part of the
+child in what he is doing. Interest is undeniably the open sesame to
+desirable mental development; but what he does protest against is that not
+uncommon interpretation of interest which deems it necessary to eschew
+most serious consideration of a subject and evade such parts as present
+difficulties. Certainly if there is any fact that stands out prominently
+in human experience it is the fact that nothing conduces to the
+development of moral stamina so much as the overcoming of difficulties,
+particularly distasteful difficulties.</p>
+
+<p><b>Conduct Developed Through Actual Performance.&mdash;</b>Self-control and the will
+to do can be trained and crystallized into habit as well as can any other
+activity. It is a fact that one well grounded in morals by habit will
+successfully resist subconscious impulsions to wrongdoing even when
+suggested in the hypnotic state. Conduct is largely a matter of growth
+through actual performance. For proper guidance of this growth there must,
+of course, be high ideals around which the feelings are led to cluster and
+by which they gradually come to be controlled.</p>
+
+<p><b>Construction of Ideals.&mdash;</b>The construction of such ideals through example,
+through precept, through appeal and through actual practise in self-denial
+and self-control on the part of the child, should be the foremost duty of
+the parent or teacher. Above all it should be remembered that imitation of
+teacher, of parents, of companions, is more of a factor than intellect in
+the moral action of children. At present<span class="pagenum"><a name="Page_224" id="Page_224">[Pg 224]</a></span> educationally we are in a fever
+for vocational training, for &#8220;practical&#8221; work, and in general for all
+things conducive to coaching our pupils in how to make a living, yet
+commendable as all this may be, is it not of even more fundamental
+importance to train them how to live?</p>
+
+<p><b>The Realization of Certain Possibilities of the Germ Rather Than Others Is
+Subject to Control.&mdash;</b>It may be said in a sense that there exists
+potentially in any germ all the things that can possibly come out of it
+under any obtainable conditions of environment. The very initiation of a
+given mode of expression by some environmental factor, however, often
+mutually excludes many of the others. We get a given average result
+ordinarily because development normally takes place in a given average
+environment.</p>
+
+<p>As may be easily shown by experiment, this is manifest even in the
+instincts of lower animals. In the young the various instincts do not come
+into expression at the same time, and it not infrequently happens that if
+one of the earlier instincts becomes operative toward certain objects or
+situations, later instincts will have a wholly different relation toward
+these objects or situations than they would otherwise have had. As a
+result the whole life conduct of the animal is markedly modified. For
+example, young animals immediately after birth have no instinct of fear.
+They do, however, have a strong instinct to attach themselves to some
+moving thing and follow it. The utility of such an instinct, as for
+instance in the case of young chickens, is obvious. The object of
+attachment is usually the parent, but man may take<span class="pagenum"><a name="Page_225" id="Page_225">[Pg 225]</a></span> the place of a parent
+and the young animal will fearlessly follow him about. However if the
+young animal has had no experience with man during its earliest infancy a
+later instinct, that of fear or wildness, will have come into play and it
+will flee from him. It is clear, therefore, that by familiarizing the
+young animal with man before its instinct of fear has come to expression,
+certain habitual reactions are set up in it which inhibit or limit the
+application of its instinct of wildness as regards man. In other words,
+the whole course of its life has been altered by this simple experience.
+The same principle applies in even greater degree to the young of man.</p>
+
+<p>We have seen in a former chapter that what in the ordinary course of
+nature was &#8220;predestined&#8221; to become one individual nevertheless contained
+the possibility of becoming four or more if the environing conditions were
+made such as to bring about a separation of the cleavage blastomeres. Or a
+fish egg that contained the possibility of becoming a normal two-eyed form
+also contained the possibility of becoming a one-eyed form and could be
+made to do so by certain unusual modifications of the conditions under
+which it develops. However we must not be led so far by the plausibility
+of this comparison that we are misled, for the fact is that we are not
+creating anything new by these environmental upheavals, but are mainly
+altering features that already exist. Beyond doubt the nature of the
+material is of greater import in the specificity of the outcome than are
+the external forces brought to play on it. The only point I wish to make
+is that even what seem ordinarily to be predestined ends can be<span class="pagenum"><a name="Page_226" id="Page_226">[Pg 226]</a></span> altered
+by environment, and that the probabilities are that certain features are
+relatively indifferent at their inception, the environmental factor adding
+the final touch of specificity. And our common experience in education
+would indicate that the same is true of mental conditions, including
+behavior. The actual appearance of a particular trait is not necessarily
+always a matter of an initial trend, but may be due merely to the fact
+that its development is possible under certain conditions of environment
+and that these conditions have prevailed in the given instance. And even
+where there is a specific bent it may be arrested through the awakening of
+a contrary impulse, or, on the other hand, its exercise may prevent the
+engendering of the opposite impulse.</p>
+
+<p><b>Our Duty to Afford the Opportunity and Provide the Proper Stimuli for the
+Development of Good Traits.&mdash;</b>It is clearly our duty to see that the
+expression of good traits is made possible. We must throw a sheltering
+screen of social environment around the young individual which will fend
+off wrong forms of incitement and chances for harmful expression, and we
+must provide proper stimuli and afford opportunity for development of
+proper modes of expression. We must not forget that a normal instinct
+denied a legitimate outlet will not infrequently find an illegitimate one.
+Above all we must not forget the vital importance of establishing correct
+habits nor the possibility of even replacing undesirable ones by good
+ones. If training can redirect the machine-like behavior of as lowly a
+creature as the starfish into new courses, why should we be so willing as
+some of our<span class="pagenum"><a name="Page_227" id="Page_227">[Pg 227]</a></span> genetists would seem to be to throw up our hands and admit
+failure in the case of man before we have even made a rational attempt to
+correct the evils in question? Even in lowly organisms we have seen that
+behavior is not only the result of an innate constitution but also of the
+degree and kind of stimulations to which it has been subjected.</p>
+
+<p>If the individual himself has not the initiative or will to make the
+attempt to set up proper or corrective habits, or to cultivate the
+necessary specific inhibitors, then all the more is it our duty to see
+that he is led by suggestion and drill into the proper routine of
+activities for their establishment. For if the individual with
+propensities toward moral obliquity is to be saved to society it must be
+through the stereotyping effects of good habits.</p>
+
+<p><b>Moral Responsibility.&mdash;</b>Beyond question different men have different
+degrees of capacity for mental and moral training. All can not be held
+equally responsible ethically, but the lowermost limit of obligatory
+response to social and ethical demands necessary to rank one as within the
+pale of normal conduct is at such a level that any one not an actual
+defective can in a reasonably wholesome environment surmount it. All
+normal men are responsible for their conduct.</p>
+
+
+
+<p>&nbsp;</p><p>&nbsp;</p>
+<hr style="width: 50%;" />
+<p><span class="pagenum"><a name="Page_228" id="Page_228">[Pg 228]</a></span></p>
+<h2><a name="CHAPTER_VIII" id="CHAPTER_VIII"></a>CHAPTER VIII</h2>
+<p class="title">MENTAL AND NERVOUS DEFECTS</p>
+
+
+<p>Some of the most important and serious problems which confront humanity
+to-day lie in the realm of mental and neural maladjustments. For human
+progress and social welfare are in last analysis based fundamentally on
+the results of normal reactions of human nervous systems. Any serious
+derangement of the latter may, and in certain cases must, lead to more or
+less disaster for the individual and disorder for society of which he is a
+unit. So appalling has the number of neuropathic subjects become in modern
+times that the matter may well cause even the most thoughtless citizen to
+pause and consider.</p>
+
+<p><b>Prevalence of Insanity.&mdash;</b>As to the prevalence of insanity, one learns from
+recent charts prepared by a member of the National Committee for Mental
+Hygiene that in 1910 we had more insane (187,454) in our institutions than
+there were students (184,712) in all our colleges and universities in the
+United States, or officers and enlisted men (142,695) in our combined
+United States army, navy and marine corps; further, the yearly cost
+($32,804,450) of caring for these insane is greater than the annual cost
+of construction ($32,520,100) on such a stupendous undertaking as the
+Panama Canal. In New York over twenty<span class="pagenum"><a name="Page_229" id="Page_229">[Pg 229]</a></span> per cent. of the revenues of the
+state go to support the insane. Doctor Lewellys F. Barker, President of
+the National Committee for Mental Hygiene, says: &#8220;It is calculated that
+some 250,000 people in the United States are insane. One of every five men
+discharged from the United States army for disability is discharged
+because of insanity, 60 per cent. of the cases being <i>dementia precox</i>.&#8221;</p>
+
+<p>Even in individual states with exceptionally large university populations
+we still find these outnumbered by those of the insane. Thus in Wisconsin
+by 1914 the state university had attained a population of about 4,700
+students resident at the university during the regular school year, and of
+approximately 6,000 attending during some part of the year, but the number
+of insane under restraint in public institutions in the state June 20,
+1912, was 6,851, with an additional 1,284 on parole. This does not include
+the insane in various private sanatoria, and moreover a considerable
+greater number of patients had been treated in these public institutions
+than were resident there June twentieth.</p>
+
+<p>To make such comparisons complete one should, of course, know the average
+length of residence of students in college, and of insane patients in
+institutions. No accurate data on this point are at hand. The average
+period of residence in hospitals for the acutely insane is doubtless
+considerably shorter than the average period of attendance of students in
+college, while on the other hand the average period of residence of
+inmates in asylums for chronic insane is probably considerably longer. For
+example, the Wisconsin State<span class="pagenum"><a name="Page_230" id="Page_230">[Pg 230]</a></span> Hospital for the Insane reports a total of
+1,224 patients under treatment, but an average population at any one time
+of only 622 during the year 1911, and the Northern Hospital for the
+Insane, a total of 1,194, with a daily average of 613 during the same
+period. The combined thirty-four county asylums in Wisconsin, for chronic
+insane, had a total population of 5,384 during the year 1911, with a loss
+of 517, or approximately 10 per cent. During 1912 the figures for these
+same institutions run 5,758 and 742 respectively, or a loss of over 12.5
+per cent. The conditions in other states are probably much the same.</p>
+
+<p>In other representative states we find the number of insane in public
+institutions as follows: California, 7,909; Michigan, 7,703; Minnesota,
+5,329; Pennsylvania, 16,992. Epileptics are estimated by alienists to be
+about equal in number to the insane, feeble-minded to be more numerous.
+The estimate that in the United States there are 300,000 feeble-minded is
+probably a minimal figure.</p>
+
+<p><b>Imperfect Adjustments of the Brain Mechanism Often Inheritable.&mdash;</b>The
+outside layer or &#8220;cortex&#8221; of the brain is the region in which the more
+complicated adjustments occur, especially such as pertain to human
+behavior, and inasmuch as this portion of the brain is extremely complex
+and delicate in its mechanism, it is peculiarly liable to derangements
+which, even when slight, may have far-reaching effects.</p>
+
+<p>This brain-mechanism is as much a product of ancestry as is any other
+structure of the body, and it is obvious therefore that imperfect
+adjustments of its structure must be as subject to the laws of
+inheritance<span class="pagenum"><a name="Page_231" id="Page_231">[Pg 231]</a></span> as are other malformations of the body. And just as with
+other defects, mental disorders may thus flow from pre-existing ancestral
+maladjustment of the nervous system or from immediate causes thrust upon
+it, such as syphilis, alcoholism, degeneration of the blood vessels and
+traumata. Or, in other words, the mechanism of mentality may be faulty
+from the beginning, or it may be made faulty by bad environmental
+conditions.</p>
+
+<p>The records of the inheritance of insanity, imbecility, feeble-mindedness
+and other forms of nervous and mental defects are truly startling. Active
+researches in this field have been in progress now for several years, and
+as each new set of investigations comes in the tale is always the same. It
+is questionable if there is a single genuine case on record where a normal
+child has been born from a union of two imbeciles. Yet the universal
+tendency is for defective to mate with defective. Davenport gives a list
+of examples, beginning with such a one as this: &#8220;A feeble-minded man of
+thirty-eight has a delicate wife who in twenty years has borne him
+nineteen defective children.&#8221; Little wonder, in the light of such facts as
+these, that the number of degenerates is rapidly increasing in what are
+called civilized countries.</p>
+
+<p><b>Many Mental Defectives Married.&mdash;</b>But, it may be urged, these are
+exceptional cases, there is surely no considerable number of mental
+defectives who are married. Let us look at the available facts. In Great
+Britain in 1901, of 60,000 known feeble-minded, imbeciles and idiots,
+19,000 were married, and in the same year, of 117,000 lunatics, 47,000
+were married; that is,<span class="pagenum"><a name="Page_232" id="Page_232">[Pg 232]</a></span> a sum-total of 66,000 mentally defective
+individuals were legally multiplying, or had had the opportunity to
+multiply their kind, to say nothing of the unmarried who were known to
+have produced children.</p>
+
+<p>In the state of Wisconsin I note from the tenth biennial report of the
+Board of Control that of 574 patients admitted to the Northern Hospital
+for the Insane during the year from July 1, 1908, to June 30, 1909, 274
+were married and 29 others were known to have been married; this is a
+total of 303 out of 574, considerably over half. At the Wisconsin State
+Hospital for the Insane we find the conditions are no better, for out of
+499 admitted in the year 1909-10, 208 were married and 65 others had at
+some time been married, or a total of 273 out of 499. There is every
+reason to believe that conditions are approximately similar in other
+states.</p>
+
+<p><b>Disproportionate Increase in the Number of Mental Defectives.&mdash;</b>Writing of
+conditions in England the Commissioners in Lunacy state in their
+fifty-fourth report that now (1901) there is one officially known lunatic
+to 301.32 individuals of population, whereas in 1859 there was only one to
+536 individuals of population. In Great Britain, taking into account
+mental defectives of all kinds, the 1901 census showed a total of 485,507,
+or 1:85 of total population. Rentoul estimates that 1:50 would be nearer
+the truth because of the fact that the number of officially known mental
+defectives is much less than the actual number. The conditions in Ireland
+are even more impressive, for in 1851 there was one known lunatic to 657
+individuals of population; in 1871, one to 328, and in 1901 one to<span class="pagenum"><a name="Page_233" id="Page_233">[Pg 233]</a></span> 178.
+When all allowance is made in these statistics for the greater accuracy of
+recent enumeration, and for other modifying influences, such as migration,
+we are still forced to believe that an alarming increase in insanity is in
+progress and that society is woefully derelict in permitting the marriage
+of such unfortunates.</p>
+
+<p>A census of the insane under public care in Wisconsin June 30, 1910, not
+counting the paroled, shows 6,537, or one to each 357 of population, since
+the population of the state was then 2,333,860. If, however, we should add
+the number of insane in private sanatoria and the number unconfined the
+proportion of normal individuals would be very much reduced.</p>
+
+<p>In the United States as a whole, while I know of no data giving the number
+of married insane, it is estimated that at least one-fourth of the insane
+are not in asylums or hospitals. In all states the number of insane in
+state institutions (there are no available records of most private
+institutions) is rapidly increasing. According to the special census of
+1903 covering a period of fourteen years, during which the general
+population increased thirty per cent., the number of insane in
+institutions increased one hundred per cent. This is due doubtless in part
+to the fact that because of better facilities for keeping them a
+proportionately greater number of insane are being sent to state hospitals
+than in former years. Moreover, improved sanitation has cut down the
+death-rate in asylums. The increase is in such vastly greater proportion
+than the increase in general population, however, that it seems impossible
+to attribute it wholly to the greater accuracy<span class="pagenum"><a name="Page_234" id="Page_234">[Pg 234]</a></span> of recent enumerations and
+the increasing custom of confining the insane in asylums. This is a matter
+that demands our gravest attention and one that should be investigated
+with the greatest thoroughness. One of the most disquieting facts in the
+situation in most states is that many patients&mdash;an average of
+approximately one thousand a year, in Wisconsin for example&mdash;are on parole
+subject to recall. This means that although it is recognized that these
+patients are likely to have to be returned to the asylum or hospital,
+little or no restraint in the meantime is placed on their marital
+relations.<a name='fna_8' id='fna_8' href='#f_8'><small>[8]</small></a></p>
+
+<p><b>Protests Voiced by Alienists.&mdash;</b>Is it any wonder under the circumstances
+that we find Doctor Charles Gorst, superintendent at the Mendota Hospital,
+voicing in his 1910 report the following vigorous protest&mdash;and certainly
+such men as he are in the best position to know. He says: &#8220;No one doubts
+for a moment that defective mental conditions are transmitted from parent
+to child as surely as the physical defects and deformities. Every one
+knows that it is common for defectives to be attracted to each other and
+marry, and that the defects of both parents are liable to be transmitted
+to the children. It is also true that there are more children born in such
+families; and for that<span class="pagenum"><a name="Page_235" id="Page_235">[Pg 235]</a></span> reason the percentage of defectives is continually
+on the increase. The report of the state of Illinois shows the increase to
+be alarming, and many other states are no better. It is absolutely wicked
+that the persons suffering from periodical insanity should be allowed to
+return to their homes to propagate and scatter their children about the
+state as dependents.&#8221;</p>
+
+<p><b>Examples of Hereditary Feeble-Mindedness.&mdash;</b>No one can look at the
+remarkable series of charts and records brought together by Doctor Goddard
+of the institution at Vineland, New Jersey, and by other directors of
+similar institutions, and doubt for an instant the inheritability of
+feeble-mindedness and allied defects. In some instances the family history
+has been followed back as far as five generations, and it is always the
+same dire sequence of insanity, idiocy, epilepsy or feeble-mindedness,
+from generation to generation. For example, Fig. 33, <a href="#Page_236">p. 236</a>, is one of
+Doctor Goddard&#8217;s charts. It shows thirteen descendants of a supposedly
+normal father (possibly a carrier) and a feeble-minded mother, of whom
+seven were feeble-minded, the others dying in infancy. The mother herself
+was one of seven feeble-minded children, who were in turn the descendants
+of feeble-minded parents, of whom the woman had five feeble-minded
+brothers and sisters. In Fig. 34, <a href="#Page_237">p. 237</a>, he shows mental defects running
+through four generations. Fig. 35, <a href="#Page_238">p. 238</a>, is a remarkable exhibit which,
+starting in the fifth generation back with a feeble-minded, alcoholic
+man&mdash;the mental condition of his wife being unknown&mdash;shows that in every
+generation down to and including the present there has been nothing but
+<span class="pagenum"><a name="Page_236" id="Page_236">[Pg 236]</a></span>feeble-minded (or worse) offspring, leaving out of account two unknown
+and a number who died in infancy without revealing their mental condition.
+This is true notwithstanding the fact that in the course of the various
+generations there had been several matings with apparently normal
+individuals. The new blood, however, instead of redeeming the tainted
+stock, itself became vitiated. The numerous specific cases of inheritance
+of family traits reviewed in recent books or in special reports of trained
+workers give us abundant confirmatory evidence of the inevitable
+inheritance of various nervous and mental defects.</p>
+
+<p>&nbsp;</p>
+<div class="figcenter"><img src="images/img31.jpg" alt="" /></div>
+<p class="center"><span class="smcap">Fig. 33</span></p>
+
+<p class="descrip">Inheritance of feeble-mindedness (after Goddard): squares represent males,
+circles females; F, feeble-minded; N, normal; E, epileptic; I, insane; C,
+criminal; T, tuberculous; d. inf., died in infancy; the hand shows the
+individual from whom the record was traced back; small black circle indicates miscarriage.</p>
+<p>&nbsp;</p>
+
+<p><b>Difficult to Secure Accurate Data.&mdash;</b>It is obvious, of course, that in
+tabulations such as these there may lurk considerable margins of error.
+Notwithstanding our Binet-Simon and other tests for feeble-mindedness, for
+example, there is yet much to be desired in<span class="pagenum"><a name="Page_237" id="Page_237">[Pg 237]</a></span> the way of accuracy. Many
+cases just bordering normality are by no means easy to decide. Then again
+in most human records, when one gets back beyond the third or, at most,
+the fourth generation, the investigator has to depend on the hearsay
+evidence of relatives, friends or neighbors, and how vague this generally
+is can only be appreciated by those who have themselves tried to collect
+such data. But in spite of all the difficulties, there is little doubt
+that the more carefully prepared records are sufficiently accurate to
+establish the fact beyond dispute that defective tends in large measure to
+breed defective.</p>
+
+<p>&nbsp;</p>
+<div class="figcenter"><img src="images/img32.jpg" alt="" /></div>
+<p class="center"><span class="smcap">Fig. 34</span></p>
+
+<p class="center">Inheritance of feeble-mindedness (after Goddard); symbols same as in Fig. 33, <a href="#Page_236">p. 236</a>.</p>
+<p>&nbsp;</p>
+
+<p>One serious drawback in making a study of the inheritability of insanity
+and other nervous disorders is that so far we have dealt mainly with mass
+effects rather than specific neuroses. But even when the latter is
+attempted we are confronted by the fact that there are various
+intergradations of the <span class="pagenum"><a name="Page_238" id="Page_238">[Pg 238]</a></span>recognized types of defect, that because of
+varying degrees of defect in the same type a standard is hard to
+establish, and above all that what appears as a specific mental malady in
+one individual may crop out in his descendants in an entirely different
+guise. Moreover, not only the predisposition of the individual, but age
+and precipitative cause enter as factors in determining the ultimate
+symptoms.</p>
+
+<p>&nbsp;</p>
+<div class="figcenter"><img src="images/img33.jpg" alt="" /></div>
+<p class="center"><span class="smcap">Fig. 35</span></p>
+
+<p class="center">Inheritance of feeble-mindedness (after Goddard); symbols same as in Fig. 33, <a href="#Page_236">p. 236</a>.</p>
+<p>&nbsp;</p>
+
+<p><b>Feeble-Mindedness and Insanity Not the Same.&mdash;</b>Authorities make a sharp
+distinction between insanities on the one hand and feeble-mindedness on
+the other. According to Goddard, not only is there no close relationship
+between the two conditions, but in reality they stand at opposite ends of
+the psychical scale. In general, insanity is a degenerative process,<span class="pagenum"><a name="Page_239" id="Page_239">[Pg 239]</a></span>
+whereas feeble-mindedness is an arrest of development. In the first case
+the victim loses part of the mentality he once had, in the second he stops
+short of normal development.</p>
+
+<p><b>Many Types of Insanity.&mdash;</b>The commonest manifestations of insanity are
+undue depression, apathy, excitement, instability, obsessions,
+hallucinations and delusions. Some mental disorders are associated with
+recognizable structural changes in the nervous system, but the structural
+basis of many is not known.</p>
+
+<p>In general there is more doubt about the inheritability of some of the
+insanities than about cases of mental deficiency. The term insanity is
+merely a loose descriptive one, and we shall gain little definite
+knowledge about the inheritance of such maladies until we study each
+separate insane diathesis specifically. Psychiatrists recognize many
+different forms of insanity, some of them very distinct from others and
+the product of unrelated underlying causes. Often it is only a question of
+degree or sometimes a matter of chance as to whether a given individual is
+certified as insane or not. A neuropathic person who manifests certain
+anti-social activities is sure to be classed as insane, whereas another
+individual with the same diathesis in a less degree might pass
+unrecognized. It is almost impossible in some instances to tell just where
+the border-line between a neuropathic and a normal constitution lies. Many
+of the idiosyncrasies of the insane, indeed, are merely exaggerations of
+characteristics seen in normal people. Recent studies of the psychology of
+the insane show that most of their hallucinations and delusions are
+closely related to<span class="pagenum"><a name="Page_240" id="Page_240">[Pg 240]</a></span> some previous mental experience they had before
+becoming insane. And it has been found that the surest means toward
+removing the obsessions of the patient in curable cases is to ferret out
+these earlier experiences and correct the wrong impressions regarding
+them. Again, certain forms of insanity do not become manifest except as
+special reactions to particular environmental conditions, and if these
+conditions do not happen to occur, then the neuropathic constitution
+though existing would not be revealed. Certain critical periods of life
+such as puberty, pregnancy and the close of sexual life are particularly
+likely to test out the mentally unstable, although such individuals may
+have maintained normal mental balance up to the crisis in question.</p>
+
+<p><b>Not All Insanities of the Same Eugenical Significance.&mdash;</b>Of the various
+kinds of insanity some seem to be of much greater eugenical significance
+than others, not only because they are strongly heritable, but also
+because of the periodicity of the attacks. The patient may be repeatedly
+in and out of the asylum and in his sane intervals wholly unrestrained as
+far as propagating his kind is concerned. <i>Manic depressive</i> psychoses and
+<i>dementia precox</i> in the order named represented the largest number of
+admissions to the Wisconsin State Hospital for the Insane in 1911 and
+1912, and both of these very frequently have a hereditary basis. Fig. 36,
+a chart showing the insanity in a local family as worked out by one of my
+pupils, is a good example of a recurrent type. The father (Fig. 36, <a href="#Page_241">p. 241</a>)
+was about eighty-two years old when the record was made. His memory
+was poor and he could<span class="pagenum"><a name="Page_241" id="Page_241">[Pg 241]</a></span> not talk connectedly, although this was possibly
+attributable to old age rather than to insanity. His brother, written to
+in Ireland, stated that to his knowledge there had never been insanity in
+his side of the family. The mother (2) was insane at nine, again at
+twenty-nine and again at thirty-six. In her later life she has been in the
+Mendota Hospital for the Insane five times and in the County Asylum twice.
+The eldest daughter (3) has been in the State Asylum five times and is now
+at home. The next daughter (4) spent five months in the asylum in 1885.
+Another daughter (5) likewise spent a short period in the asylum. Two sons
+(6, 7) have each spent two periods in the asylum, and a third son (8) has
+had an attack of insanity. The youngest child died at the age of three.
+Thus of the eight adult children six have been insane at some time. The
+cases in this family seem all to be instances of manic-depressive
+insanity.</p>
+
+<p>&nbsp;</p>
+<div class="figcenter"><img src="images/img34.jpg" alt="" /></div>
+<p class="center"><span class="smcap">Fig. 36</span></p>
+
+<p class="center">Inheritance of insanity in the L&mdash;&mdash; family. See text for description.</p>
+<p>&nbsp;</p>
+
+<p><b>A Neuropathic Constitution May Express Itself Differently Under Different
+Conditions.&mdash;</b>Some of<span class="pagenum"><a name="Page_242" id="Page_242">[Pg 242]</a></span> the difficulties of getting genealogies of specific
+forms of insanity are obvious from the following quotations chosen from
+the works of eminent psychiatrists. Kraepelin, for instance, expresses the
+opinion that: &#8220;The psychopathic charge of a family may reveal itself not
+only by the appearance of mental disorders but also by other forms of
+manifestation. Here belong before all, those diverse slighter deviations
+from mental health which go to make up the borderland of insanity:
+nervousness, states of anxiety and compulsion, constitutional depressions,
+slight hysterical disorders and forms of feeble-mindedness, tics; also odd
+characters, peculiarities in mode of living, criminal tendencies, lack of
+self-control, intemperance, love of adventure, mendacity, suicide on an
+inner basis.&#8221;</p>
+
+<p>From the volume of Church and Peterson on <i>Nervous and Mental Diseases</i> a
+further confirmatory opinion may be cited: &#8220;In determining the factor of
+heredity we must not be content with ascertaining the existence of
+psychoses in the ascendants, but must seek, by careful interrogation of
+various members of the family, for some of the hereditary equivalents,
+such as epilepsy, chorea, hysteria, neurasthenia, somnambulism, migraine,
+organic diseases of the central nervous system, criminal tendencies,
+eccentricities of character, drunkenness, etc., for these equivalents are
+interchangeable from one generation to another, and are simply evidence of
+instability of the nervous system. It is the unstable nervous organization
+that is inherited, not a particular neurosis or psychosis, and it must be
+our aim in the investigation of the progenitors to discover the evidence
+of this.&#8221;</p>
+
+<p><span class="pagenum"><a name="Page_243" id="Page_243">[Pg 243]</a></span><b>Certain Forms of Insanity, But Not All, Seem to Behave as Mendelian
+Recessives.&mdash;</b>A number of psychiatrists and investigators of the
+inheritance of insanities (Rudin, Lunborg, Davenport, Rosanoff, Jolly),
+although working independently and in different countries, concur in the
+opinion that manic-depressive insanity, dementia precox and allied
+psychopathic conditions tend to occur after the manner of a Mendelian
+recessive. On the other hand such maladies as Huntington&#8217;s chorea are
+transmitted as a dominant and in all probability at least half of the
+children of an afflicted individual will inherit and manifest the defect.
+As to inheritance of various other psychoses we have too few accurately
+charted pedigrees for most types to make very positive statements about
+their degree or manner of inheritance. Little can be said beyond the
+statement that there is a decided tendency for various forms to recur in
+offspring. Where more than one case of insanity occurs in a given family
+or stock it is strong presumptive evidence that a hereditary defect is at
+the bottom of it. As Doctor Wilmarth says, &#8220;Mental accident may occur in
+any family, but it is rarely a second case occurs unless there is a
+tendency to nerve degeneracy.&#8221; For example, of 818 insane at the Wisconsin
+State Hospital for the Insane during the biennium 1909-10, 187, or
+practically one-fourth were positively known to have insane relatives. Of
+these, 24 had insane fathers, 31 insane mothers, 30 insane brothers, 23
+insane sisters, 25 insane uncles, 21 insane aunts, and 21 insane cousins.
+Where definite information could be obtained it was found that of the
+5,700 admissions of insane patients<span class="pagenum"><a name="Page_244" id="Page_244">[Pg 244]</a></span> to the New York state hospitals
+during the year ending September 30, 1911, 27.7 per cent. of the cases
+showed a history of insanity in the family and an additional 22.9 per
+cent. showed a history of alcoholism, nervous diseases and the like.</p>
+
+<p><b>Grades of Feeble-Mindedness.&mdash;</b>As to the various grades of
+feeble-mindedness, while no sharp lines of demarcation can be drawn, a
+rough and ready test usually applied is the relative ability of such
+subnormal individuals to take care of themselves. In all, the conditions
+exist from birth or shortly after. <i>Idiots</i> are such defective individuals
+as are unable to take care of themselves even to the matter of guarding
+against common physical dangers. Their mentality does not progress beyond
+that of a two-year-old child. <i>Imbeciles</i> can take care of themselves in
+the cruder physical ways, but are unable to earn their living. Their
+mental age ranges from three to seven years inclusive. <i>Morons</i>, or the
+&#8220;feeble-minded&#8221; in a more specific usage of the term, can under proper
+direction become more or less self-supporting but they are as a rule
+incapable of undertaking affairs which demand judgment or involve
+unrestricted competition with normal individuals. Their intelligence
+ranges with that of normal children from seven to twelve years of age. The
+last class grades up insensibly into the shiftless, ne&#8217;er-do-well types
+which exist in every community. It is the hordes of the feeble-minded in
+the restricted sense that afford our most serious problems to-day. The
+idiot and the imbecile are usually early and easily recognized and are
+kept more or less under restraint, but the higher grades of feeble-minded,
+the<span class="pagenum"><a name="Page_245" id="Page_245">[Pg 245]</a></span> so-called moron type, can be detected often only by carefully devised
+tests.</p>
+
+<p><b>About Two-Thirds of the Feeble-Minded Have Inherited Their
+Condition.&mdash;</b>Concerning the various types of feeble-mindedness there is
+strong evidence that heredity is a factor of greater magnitude than in
+most insanities. All facts point to the conclusion that most mental
+deficiency is strongly inheritable and that the majority of our defectives
+of this type come from degenerate stocks. Practically all specialists at
+the heads of asylums and homes for the mentally deficient concur in the
+opinion that about two-thirds of the cases are hereditary. For example,
+Doctor Alfred Wilmarth, superintendent of the Wisconsin Home for
+Feeble-minded, says: &#8220;My own observations, and those of others in this
+country and Europe, would indicate that at least two-thirds of the
+feeble-minded have defective relatives.&#8221;</p>
+
+<p>In his study of two thousand children tested by the Binet measuring scale
+for intelligence, Doctor Henry H. Goddard, director of the Department of
+Research at the Training School for Feeble-minded at Vineland, N. J.,
+remarks concerning heredity of feeble-mindedness: &#8220;But we now know that
+sixty-five per cent. of these children have inherited the condition, and
+that if they grow up and marry they will transmit the same condition to
+their offspring. Indeed, we know that this class of people is increasing
+at an enormous rate in every community and unless we do something to stop
+this great stream of bad protoplasm we shall some day be swamped in a sea
+of degeneracy.&#8221;</p>
+
+<p>E. R. Johnstone, superintendent of the training<span class="pagenum"><a name="Page_246" id="Page_246">[Pg 246]</a></span> school at Vineland, N.
+J., in a recent bulletin remarks concerning feeble-minded and epileptics,
+&#8220;We are now convinced that from sixty to eighty per cent. of the cases are
+hereditary.&#8221;</p>
+
+<p>Again, we find Doctor A. C. Rogers, superintendent of a school for
+feeble-minded in Minnesota, saying, &#8220;We have no survey of mentality in
+this country except in very small areas, but probably about sixty-five per
+cent. of the feeble-minded children that we know of are feeble-minded from
+heredity; that is, they come from families in which there is much
+feeble-mindedness, usually associated with various neuroses or psychosis.
+There are about thirty-five per cent. approximately that are acquired
+cases. These cases develop from various things. Full development may be
+prevented during gestation, or early childhood, or early adolescence, but
+these acquired cases are entirely distinct from the hereditary ones.&#8221;</p>
+
+<p>In a recent paper Doctor Martin W. Barr, chief physician for the
+Pennsylvania Training School for Feeble-minded Children, says: &#8220;In my
+individual study of 4,050 cases of imbecility, I find 2,651, or 65.34 per
+cent., caused by malign heredities; and of these 1,030, or 25.43 per
+cent., are due to direct inheritance of idiocy; and 280, or 6.91 per
+cent., to insanity.&#8221; From these figures it will be seen that Doctors Barr,
+Goddard, Wilmarth, Johnstone and Rogers all agree in their estimates;
+namely, that two-thirds of our imbeciles are so through inheritance.</p>
+
+<p><b>Some Results of Non-Restraint of the Feeble-minded.&mdash;</b>The following excerpt
+from a paper by<span class="pagenum"><a name="Page_247" id="Page_247">[Pg 247]</a></span> Doctor Barr, is a fair sample of what happens when such
+defective individuals are not restrained from propagating their kind:</p>
+
+<div class="blockquot"><p>&#8220;My own study and observation alone, of over 4,000 degenerates, shows
+such examples as: A man 38 years of age, the father of 19 defective
+children, all living, he and his wife both under par mentally; as was
+another couple, with 9 imbecile children; an idiot woman with 7 idiot
+children. A forcible instance is that of a man with two daughters and
+one illegitimate grandchild, all feeble-minded.... I could name a
+family, one of the proudest in the land, where there are five
+children, an aunt and two uncles, all feeble-minded.</p>
+
+<p>&#8220;Yet another, which in seven generations numbering some 138
+individuals, records 10 still-born children (premature births), 16
+insane, 7 imbeciles, 3 epileptics and 32 with mental peculiarities so
+pronounced as to occasion remark. Of the 138 there remain 80
+apparently normal, who are nevertheless hopeless slaves of a neurotic
+heredity, direct or collateral.</p>
+
+<p>&#8220;In a study of 15 imbecile girls, 3 were recognized prostitutes, 9 had
+each 1 illegitimate child (2 being the result of incestuous
+intercourse with brothers); 1 had 2; 2 epileptics had, the one 3, and
+the other 4 idiot children.</p>
+
+<p>&#8220;Four feeble-minded women had 40 illegitimate children.</p>
+
+<p>&#8220;A feeble-minded woman living in an almshouse since early childhood,
+allowed to go out to service periodically, had given birth to six
+illegitimate children, all inheriting her defect.</p>
+
+<p>&#8220;An imbecile drunkard is the father of three feeble-minded children.
+The daughter, seduced before the age of sixteen, gave birth to an
+idiot child; one son is <span class="pagenum"><a name="Page_248" id="Page_248">[Pg 248]</a></span>a harmless imbecile, but the other is a moral
+imbecile, a sexual pervert, a thief on the streets, and a pyromaniac,
+firing in sheer wantonness a large mill property.</p>
+
+<p>&#8220;Another shows the entire family for three generations below normal.
+Father, mother, mother&#8217;s sister, and father&#8217;s uncle, all imbecile.
+Five children feeble-minded. One girl had a proposal of marriage, and
+one boy is married to a feeble-minded girl.</p>
+
+<p>&#8220;One insane woman, whose brother and sister committed suicide, had
+five sons. The oldest, feeble-minded, a drunkard and hobo, had one
+son, a criminal. The second son, insane, had three imbecile children.
+The third, an insane epileptic, had three imbecile sons, one of whom
+was an epileptic. The fourth son was insane. The fifth, apparently
+normal, had a morally imbecile son and an epileptic daughter.&#8221;</p></div>
+
+<p>Yet striking as is the inheritance of these maladies, Doctor Barr points
+out that of the 10,000 known cases of feeble-mindedness in Pennsylvania,
+only 3,500 are sequestrated. This leaves a balance in that state of 6,500
+totally irresponsible individuals to work havoc in society by producing
+their kind.</p>
+
+<p><b>Inheritance Not a Factor in Some Cases of Mental Deficiency.&mdash;</b>On the other
+hand as our data show, there remain about one-third of the mentally
+deficient type to be accounted for on other than a basis of heredity. As
+already noted, some of these are doubtless the product of suppressions of
+normal development by various extraneous factors operating before or
+shortly after birth. There is one class particularly, estimated by some
+authorities as constituting as high as thirty per cent. of the
+feeble-minded which is unusually puzzling. These are the so-called
+mongolians. The<span class="pagenum"><a name="Page_249" id="Page_249">[Pg 249]</a></span> name is given because the features of such individuals
+bear more or less resemblance to those of some of the Mongolian races. The
+defect does not seem to be hereditary although it is usually congenital.
+It appears to be due to something which interferes with prenatal
+development. Whatever the conditions, whether lack of nutrition in the
+mother, alcoholic or other poisoning, the cases seem to be as hopelessly
+incurable as are the hereditary forms. From the social standpoint, of
+course, such individuals are in their immediate generation, as incompetent
+or as dangerous to society as those suffering from the more surely known
+hereditary forms of mental defect.</p>
+
+<p><b>Epileptics.&mdash;</b>Although epileptics are not classed as imbeciles ordinarily,
+as a matter of fact no sharp distinction can be drawn between the two
+classes. Doctor Wilmarth says, &#8220;Epilepsy and mental deficiency are as
+closely related as branches on the same tree.... Over one-half and perhaps
+two-thirds of all feeble-minded are subject to convulsive seizures at some
+period of their lives, and we are never surprised at the appearance of
+epilepsy in any feeble-minded person. On the other hand, so small a
+percentage of epileptics maintain normal mental actions as hardly to be
+worth consideration ... even those who retain a normal mind in the early
+stages of the diseases almost infallibly become imperfect later.&#8221; How
+slight a chance the epileptic has of ever becoming normal may be inferred
+from a statement made by Doctor Frank Billings in a paper read before the
+Illinois State Medical Society in 1909 to the effect that &#8220;ten per cent.
+or more can be cured by proper care.&#8221;</p>
+
+<p><span class="pagenum"><a name="Page_250" id="Page_250">[Pg 250]</a></span>According to the estimates of &#8220;The Committee of Fifty&#8221; in the state of
+Illinois, who have been agitating for the establishment of a colony for
+epileptics, there are 10,000 of these unfortunates in that state. The
+consensus of opinion of experienced workers in various states is that
+there is about one epileptic to each three hundred fifty to five hundred
+inhabitants.</p>
+
+<p><b>In Heredity Conditions of Feeble-Mindedness Are Probably Recessive to
+Normal Condition.&mdash;</b>As to the mode of inheritance of the various forms of
+feeble-mindedness, the evidence points to such defects in the main as
+being recessive. However, no particular grade can be picked out and shown
+to be a pure recessive. For instance, the children of two epileptics will
+be defective but it is impossible to predict always whether the defect
+will appear as epilepsy or feeble-mindedness. This is doubtless due to the
+fact that mental deficiencies even of the inheritable type are not all due
+to the same specific cause, and in many cases the individual is defective
+in more than one direction. If one or more of a great number of units
+which are necessary for complete mental development are lacking, obviously
+mental deficiency will result. In other words, feeble-mindedness and
+allied disorders may not be definite characters, but simply evidences of
+the fact that the nervous system has not developed all factors necessary
+for normal mental coordination. Goddard, however, one of our best
+authorities on the heredity of feeble-mindedness, is inclined to regard
+the condition as a unit character, &#8220;due either to the presence of
+something which acts as an inhibitor, or<span class="pagenum"><a name="Page_251" id="Page_251">[Pg 251]</a></span> due to the absence of some
+stimulus which sends the normal brain on to further development.&#8221;</p>
+
+<p>Supposing nervous defects finding expression in feeble-mindedness,
+epilepsy and related conditions, to act as a Mendelian recessive, then the
+marriage of one such defective with another should yield only mentally
+enfeebled offspring. How nearly this expectation may be realized is seen
+from the following examples.</p>
+
+<p>In an extensive study<a name='fna_9' id='fna_9' href='#f_9'><small>[9]</small></a> of feeble-mindedness, just from the press, Doctor
+Henry H. Goddard points out that of 482 children with both parents
+feeble-minded all but six were feeble-minded. Even the exceptions may be
+apparent rather than real as there is possibility of mistake in judging
+the condition of the parents or of the children themselves. Moreover, with
+the feeble-minded one is not always sure of the paternity of a child, as
+is instanced by Doctor Goddard in a case quoted from Doctor Emerick in
+which of twelve children in a white family with both father and mother
+feeble-minded ten were feeble-minded and two were not, but these two were
+<i>mulatto</i> children.</p>
+
+<p>In a paper by Weeks (<i>The Inheritance of Epilepsy</i>), in part an extension
+of an earlier joint paper by Davenport and Weeks, is recorded among others
+a study of twenty-seven fraternities in which both parents were either
+epileptic or feeble-minded. Of the 28 progeny, 19 lived long enough to
+reveal their mental state. Of these 3 were feeble-minded, 8 epileptic and
+8, from parents who developed epilepsy late in life, were what Doctor
+Weeks terms &#8220;tainted.&#8221; In 15<span class="pagenum"><a name="Page_252" id="Page_252">[Pg 252]</a></span> fraternities in which one parent was
+epileptic and the other feeble-minded he found there had been 81
+conceptions. Of these 7 were too young to classify and 19 had died before
+fourteen years of age. Of the remaining 55, 28 were epileptic, 26
+feeble-minded, and 1 insane. Again, in 9 families in which the parents
+were both feeble-minded, of the 38 surviving offspring who were old enough
+to classify, 7 were epileptic, 29 feeble-minded, and 2 drunkards. In 5
+families where one parent was insane and the other epileptic or
+feeble-minded, 5 children died before the age of fourteen, the condition
+of 2 was unknown, 2 were epileptic, 4 feeble-minded, 1 insane, 8 tainted,
+and 7 seemingly normal. Regarding the latter Doctor Weeks says they came
+from two families where in one case the father&#8217;s insanity seemed to be
+traumatic and in the other alcoholic.</p>
+
+<p>In a few cases where the defect in one parent has apparently been of a
+type different from the defect of the other parent a &#8220;normal&#8221; child was
+produced. That is, presumably each parent carried normality in the trait
+defective in the other so that the child became simplex with reference to
+each defect. Davenport points out that not infrequently two deaf-mutes
+whose defects are due to different causes may have normal children.</p>
+
+<p>In general, however, the reasonable expectation is that where two
+feeble-minded individuals marry, a very common occurrence, the children
+will all show mental deficiency. A mating between a feeble-minded person
+and one of perfectly normal stock will apparently result in normal
+children although they will be<span class="pagenum"><a name="Page_253" id="Page_253">[Pg 253]</a></span> carriers. There is some evidence, however,
+that such carriers may occasionally show &#8220;taints&#8221; of abnormality in the
+form of migraine (nervous sick headache), alcoholism, queerness, violent
+temper, etc. Thus according to the studies of Doctor Weeks, &#8220;In 50 matings
+where at least one parent is migrainous, there were 350 conceptions, of
+which number enough is known of 212 to classify 55, or 26 per cent., as
+epileptic; 12, or 6 per cent., as feeble-minded, with the others tainted
+or normal. In the 131 matings where at least one parent is alcoholic,
+there were 845 conceptions. Of the 494 classified, 151, or 31 per cent.,
+were epileptic; 54, or 11 per cent., feeble-minded, with the balance
+tainted or normal.&#8221; Marriage between two carriers will cause the defect to
+reappear in active form in approximately 25 per cent. of the offspring and
+50 per cent. will continue to be carriers.</p>
+
+<p><b>Many Apparently Normal People Really Carriers of Neuropathic
+Defects.&mdash;</b>There is considerable evidence that many apparently normal
+individuals of our average population are in reality carriers of some form
+of neuropathic defect, some authorities placing the proportion
+provisionally at over thirty per cent. This being true, then it is easy to
+explain the apparently unaccountable appearance of epilepsy,
+feeble-mindedness, or similar defects among the children of what pass for
+normal stocks. The probabilities are that in many cases it means simply
+that the parents of the defective children have been carriers.</p>
+
+<p>As to the contention that in preventing the propagation of the
+feeble-minded we may be depriving the world of geniuses, Doctor Goddard
+remarks: &#8220;It is<span class="pagenum"><a name="Page_254" id="Page_254">[Pg 254]</a></span> a significant fact that in our three hundred family
+histories totaling 11,389 individuals not a single genius has been found.
+Not only are there no geniuses but the fact can not be too strongly
+emphasized that even the people who are considered normal ... are not as a
+rule people of average intelligence....&#8221; However, between insanity and
+genius he finds more kindred spirit.</p>
+
+<p><b>Tests for Mental Deficiency.&mdash;</b>As to tests for mental deficiency, the one
+commonly meted out to victims in the every-day world is the
+social-economic one of survival in the competitions of life. The mentally
+deficient fail. Although often unrecognized as feeble-minded they drift
+through life social and economical derelicts who have to be supported by
+the community.</p>
+
+<p>Of laboratory tests many have been devised. While all yet leave much to be
+desired, still through their application the majority of mental defectives
+can be detected. Fairly accurate standards of normality have been
+established from which the relative degree of &#8220;backwardness&#8221; can be
+determined. We have just awakened to the importance of detecting
+defectives early in life, hence many of our tests have been planned with
+reference to children. They are based not so much on training or conscious
+learning as on fundamental processes which develop at certain ages in
+children. Another impetus toward securing adequate criteria of mental
+deficiency has been the crying need of having some easily applied standard
+for detecting the very large numbers of defective immigrants who are
+continually seeking to enter the United States.</p>
+
+<p><span class="pagenum"><a name="Page_255" id="Page_255">[Pg 255]</a></span>Most of the methods consist of &#8220;performance&#8221; tests which are planned to
+test the powers of perception, concentration, application, ingenuity and
+education of the subject. Previous environment, education and the
+difficulties under which the subject may be laboring at the time of the
+test must, of course, be taken into account. It is particularly difficult
+to get adequate tests for the immigrant which will enable one to
+distinguish between ignorance, stupidity, fear and temporary psychic
+depression on the one hand, and congenital mental deficiency on the other.</p>
+
+<p>Perhaps the most successful single set of tests for mental deficiency is
+that known as the Binet-Simon Scale. From an examination of large numbers
+of French school children Binet constructed a scale of tests of increasing
+complexity accurately graded to age and previous training of the average
+normal child. In the Binet-Simon system tests are given for each age from
+three years to thirteen. When a child successfully passes the tests for
+his age he is classed as normal. If he succeeds only in tests which
+normally are those given for a child a year younger then he is backward to
+the extent of one year. Similarly he may show by these graded tests that
+he is backward to the extent of two years, three years and so on. If a
+child is more than three years backward according to the test he is
+regarded as mentally defective. Various corrections and adjustments of the
+original scale have been worked out to allow for unevenness in mental
+development. On the whole the scheme works out satisfactorily when applied
+by one skilled in its use. The attitude of the examiner, however, is of so
+great<span class="pagenum"><a name="Page_256" id="Page_256">[Pg 256]</a></span> importance that the tests are of less value in the hand of
+inexperienced workers. A revision of the scale to adapt it better to
+American children has recently been made by Doctor Goddard.<a name='fna_10' id='fna_10' href='#f_10'><small>[10]</small></a> Besides
+the Binet-Simon tests various performance tests, standardized for children
+of different ages, such as Seguin&#8217;s form board, Healy&#8217;s pictorial
+completion test, Fernald&#8217;s construction puzzle, the Rossolimo test, De
+Sanctis test, etc., are used by different investigators. Questions
+designed to reveal moral tone are also employed. Doctor Howard A. Knox,
+assistant surgeon United States Public Health Service, in a recent
+article<a name='fna_11' id='fna_11' href='#f_11'><small>[11]</small></a> gives an interesting account of the tests applied to determine
+the exact mentality of immigrants entering the United States together with
+a brief review of various tests. A full account and discussion of the
+various tests for the mentally subnormal will be found in a recent
+publication by Doctor William Healy,<a name='fna_12' id='fna_12' href='#f_12'><small>[12]</small></a> director of the Juvenile
+Psychopathic Institute, Chicago.</p>
+
+<p><b>The Backward Child in School.&mdash;</b>It is only in recent times that we have
+come to realize the seriousness of the problem which the backward child
+presents in our schools. It is of the utmost importance to discover early
+in school life which of the backward children owe their condition to
+adenoids, defective sight or hearing, poor nutrition, imperfect
+circulation, or<span class="pagenum"><a name="Page_257" id="Page_257">[Pg 257]</a></span> other remediable defects, and which are the victims of
+innate mental deficiency. The treatment of the individual must be very
+different in the two cases. In the one the condition can be cured by
+proper manipulations or other treatments; in the other it can only be
+ameliorated. All school children who are two or three years below grade
+should be rigidly inspected by the medical examiner.</p>
+
+<p>From a study of about two thousand children comprising the first five
+grades of an entire public school system Goddard found that eighteen per
+cent. were definitely &#8220;backward.&#8221; Of these between two and three per cent.
+were actually feeble-minded, the condition in the remaining fifteen per
+cent. being presumably capable of correction. Other similar surveys have
+given practically the same results.</p>
+
+<p><b>The Exceptionally Able Child Likely to Be Neglected.&mdash;</b>However, while we
+must not forget that it is important to recognize backward children and to
+see that they are segregated into small groups which are not required to
+do the full amount of work in regular time, it is equally urgent to see
+that the unusually bright individual is also given opportunity to advance
+more rapidly than the rank and file. Only too often the holding back of a
+child in school leads to lack of interest and habits of mental laziness,
+and sometimes to truancy and incorrigibility. The general attempt in our
+graded schools to keep all children close to the average is to be strongly
+condemned.</p>
+
+<p><b>Cost of Caring for Our Mentally Disordered.&mdash;</b>Doctor Charles L. Dana,
+member of the National Committee for Mental Hygiene, estimated in 1904
+that the<span class="pagenum"><a name="Page_258" id="Page_258">[Pg 258]</a></span> actual cost of caring for feeble-minded and insane in the
+United States amounted to sixty million dollars, to which should be added
+the corresponding loss in industrial activity on the part of the
+afflicted,&mdash;at least twenty million dollars more, and he figures that the
+amount was increasing at the rate of four per cent. per annum. Many
+investigators concur in the opinion that our insane and feeble-minded
+alone cost us far above one hundred million dollars. Adding to this
+economic burden the cost of our delinquents and criminals the total
+expense becomes stupendous. And when we consider still further the even
+greater burden of suffering of the unfortunates themselves and the sorrows
+of those to whom they are dear, a burden not measurable in money, the
+feeling that something must be done to relieve the situation becomes
+overpowering.</p>
+
+<p><b>Importance of Rigid Segregation of Feeble-Minded.&mdash;</b>As regards the really
+feeble-minded little can be done beyond making them as happy as possible
+and developing the limited gifts they have been given by nature. Their
+teaching must be in the main concrete and simple. At the age of puberty it
+is imperative to see that the sexes are separated and kept under
+sufficient permanent supervision to prevent all possibility of
+procreation. There is neither economic nor common sense in even allowing
+the remotest chance of such occurrences as the following: &#8220;This is the
+case of a feeble-minded and epileptic woman who had six children by
+various persons while an inmate of a county poor house. One child at the
+age of eighteen died in the almshouse, two died in infancy, one was
+epileptic (the son of a man with a criminal record)<span class="pagenum"><a name="Page_259" id="Page_259">[Pg 259]</a></span> and two who are now
+living in the almshouse are feeble-minded, one being the son of a negro.&#8221;
+Again, we find a superintendent of an English almshouse reporting that one
+hundred and two out of one hundred and five children born there in five
+years were feeble-minded.</p>
+
+<p>As conditions are to-day every institution for the feeble-minded has a
+long waiting list and the same is true of most asylums for the insane.
+Instead of providing the prolonged care necessary for such patients,
+institutions are forced to discharge many prematurely in order to make
+room for more urgent cases.</p>
+
+<p><b>Importance of Early Diagnosis of Insanity.&mdash;</b>In insanities, even when of
+hereditary origin, there is much hope in certain cases of greatly
+benefiting the individual, though a permanent cure, or at least the
+establishment of procreative fitness may be impossible. It is extremely
+important that the public realize how much can be done through early
+examination and advice in such mental afflictions. Most of the insane who
+recover usually do so within a few months of their first alienation, hence
+the importance of losing no time in detecting the condition and securing
+early treatment. It is now well known that many cases of chronic insanity
+may be measurably improved under the care of a psychiatrist by systematic
+re-education, especially in industrial lines. But how little of this may
+be expected at the hands of the untrained custodians who &#8220;feed&#8221; the
+inmates of our county almshouses, to which in many states the chronic
+insane are entrusted, is obvious.</p>
+
+<p><b>All Insane Should Be Passed Upon by Competent<span class="pagenum"><a name="Page_260" id="Page_260">[Pg 260]</a></span> Psychiatrists.&mdash;</b>The
+atrocious system of turning the chronic insane over to county poorhouses
+manned by supervisors whose chief qualification for the position has not
+infrequently been the lowness of their bid for boarding and caring for the
+inmates, can not be too strongly condemned. Incredible as it may seem, in
+some states the court can on its own judgment send patients directly to
+these institutions without first submitting them to the study of expert
+physicians in the state hospital for the insane. The viciousness of such
+procedure is evident when one realizes that often careful scrutiny on the
+part of the very best experts, extending over a considerable period of
+time, is required before the true condition of the patient can be
+determined. Recently a psychiatrist of high standing, who was gathering
+data on county asylums for a national organization, informed the writer
+that beyond the shadow of a doubt he had come across case after case in
+county asylums which would have been curable under proper treatment.</p>
+
+<p>Here again the responsibility in last analysis must rest upon us as
+citizens, for it is largely through our intelligent demands as voters that
+conditions will be improved and competent experts be put in charge of
+county asylums as well as of the state hospitals for the acutely insane.</p>
+
+<p><b>Some Insanities Not of Hereditary Origin.&mdash;</b>Some alienists believe that
+self-poisoning known as <i>auto-intoxication</i>, due to improper elimination
+of poisons generated through faulty digestion or metabolism, if of long
+standing, may be not only a contributory but a more or less direct cause
+of insanity. About twenty<span class="pagenum"><a name="Page_261" id="Page_261">[Pg 261]</a></span> per cent. of insanities of men living in cities
+and about fifteen per cent. of those living in the country seem to be
+directly related to the intemperate use of alcohol. The corresponding
+figures for women are seven per cent. and one per cent. respectively.
+General paresis or softening of the brain is probably invariably preceded
+by syphilis. About twenty-two and five-tenths per cent. of the first
+admissions to hospitals for the insane from city-dwelling men, and eight
+per cent. from men living in the country in the state of New York are
+cases of this kind of insanity. The corresponding figures for women are
+five and five-tenths per cent. and two and five-tenths per cent.
+respectively.</p>
+
+<p><b>Importance of Heredity in Insanity Not Appreciated.&mdash;</b>We have already seen
+that heredity plays an important part in insanities. There can be little
+doubt that the tendency is to under-estimate rather than over-estimate its
+importance. Many cases said to be &#8220;caused&#8221; by mental strain such as those
+occasioned by domestic infelicities, business reverses and the like should
+in all probability be fundamentally attributed to something far more
+deep-seated than the more obvious cause. In many such instances there is
+little doubt that an inherent weakness in mental make-up exists which
+predisposes the individual toward mental breakdown. This is more apparent
+when one recalls that there are thousands of other individuals who undergo
+equally great or greater calamities without loss of mental balance. There
+are well-recognized types of mental disposition which later contribute to
+corresponding forms of insanity. In many<span class="pagenum"><a name="Page_262" id="Page_262">[Pg 262]</a></span> instances the final catastrophe
+may be averted if the &#8220;peculiar&#8221; individual can be kept in good health and
+guided into right habits of thought. Undoubtedly certain infectious
+diseases, arterio sclerosis, various poisons in the blood, child-birth,
+and similar influences often enter as important contributory factors. In
+all cases of cure, however, we must face the fact that under existing
+conditions these mentally restored individuals are released into society
+without let or hindrance as regards their marital relations.</p>
+
+
+
+<p>&nbsp;</p><p>&nbsp;</p>
+<hr style="width: 50%;" />
+<p><span class="pagenum"><a name="Page_263" id="Page_263">[Pg 263]</a></span></p>
+<h2><a name="CHAPTER_IX" id="CHAPTER_IX"></a>CHAPTER IX</h2>
+<p class="title">CRIME AND DELINQUENCY</p>
+
+
+<p><b>The Relative Importance of Heredity and Environment in This Field
+Uncertain.&mdash;</b>The whole question of crime and delinquency is a highly
+complex one. Here, perhaps, more than in any other phase of race
+betterment we find the greatest difficulty in separating the effects of
+hereditary predisposition from the results of unfavorable environment.
+While there is no longer a reasonable doubt about such nervous disorders
+as epilepsy, feeble-mindedness and certain forms of insanity being rooted
+largely in ancestral taints, the degree to which crime or delinquency is
+based on heredity is far more questionable. Every student of genetics
+knows that we may have dwarf plants because the constitution of the germ
+is of a nature to produce only such individuals, or we may have dwarfed
+plants because of adverse conditions of soil and lack of an opportunity to
+climb or rise to their full capacity. Bateson pertinently remarks, &#8220;The
+stick will not make the dwarf pea climb, though without it the tall can
+never rise. Education, sanitation, and the rest are but the giving or
+withholding of opportunity.&#8221; The important sociological question for us to
+determine is which of these lowly peas of the human family are really
+dwarfs and which are dwarfed<span class="pagenum"><a name="Page_264" id="Page_264">[Pg 264]</a></span> simply because the stick of opportunity on
+which to climb is lacking.</p>
+
+<p>Beyond doubt a considerable portion of crime and degeneracy is due in
+large measure to innate inclination, but with just as little doubt much is
+the effect mainly of vicious habits acquired through an unwholesome
+environment. A normal appetite or impulse may be given a pathological
+trend by bad influences. And one has to reckon, moreover, with degrees of
+hereditary aptitude to crime. Just what is the measure of normality? To
+what extent by developing to their highest point certain inhibitive or
+opposing tendencies, can we counteract certain inherent proclivities for
+wrong-doing? By what means shall we sift the congenital defectives from
+the victims of suppressed opportunities? These and kindred questions
+confront us at the very outset of our studies of crime and delinquency. It
+is obvious that although we may institute the strictest elimination of the
+socially unfit, unless we can provide a wholesome environment for the fit,
+lapses into unfitness are sure to recur.</p>
+
+<p><b>Feeble-Mindedness Often a Factor.&mdash;</b>The conviction is steadily growing
+among students of human heredity that a considerable amount of crime,
+gross immorality and degeneracy is due at bottom to feeble-mindedness and
+that, therefore, if we can once eliminate feeble-mindedness, these vicious
+accompaniments will at the same time in equal measure disappear. Goddard,
+for example, one of our authorities on the inheritance of
+feeble-mindedness, is convinced that a large proportion of the delinquent
+girls who fill our reformatories are actually feeble-minded. They are
+often the<span class="pagenum"><a name="Page_265" id="Page_265">[Pg 265]</a></span> higher grade or moron type, and their mental condition remains
+unsuspected because they have never been thoroughly tested in this
+respect.</p>
+
+<p><b>Many Delinquent Girls Mentally Deficient.&mdash;</b>According to Havelock Ellis,
+2,500 of some 15,000 women who passed through Magdalen homes in England
+were definitely feeble-minded and were known to have added a thousand
+illegitimate children to the population.</p>
+
+<p>The preliminary reports of the so-called white slave investigations now in
+progress in New York City classes 25 per cent. of these unfortunate women
+as mentally incapable of taking care of themselves. Other investigations
+indicate that from 40 to 60 per cent. of this class of women are
+defectives. For example, from the report of the Massachusetts &#8220;Commission
+for the Investigation of the White Slave Traffic, So-Called,&#8221; one reads:
+&#8220;Of 300 prostitutes, 154, or 51 per cent., were feeble-minded. All
+doubtful cases were recorded as normal. The mental defect of these 154
+women was so pronounced and evident as to warrant the legal commitment of
+each one as a feeble-minded person or as a defective delinquent.... The
+135 women designated as normal, as a class were of distinctly inferior
+intelligence. More time for study of these women, more complete histories
+of their life in the community, and opportunity for more elaborate
+psychological tests might verify the belief of the examiners that many of
+them were also feeble-minded or insane.&#8221;</p>
+
+<p>The data from some of our public reformatories, industrial schools and
+state homes for delinquent girls,<span class="pagenum"><a name="Page_266" id="Page_266">[Pg 266]</a></span> are very instructive in this respect.
+Reports from a number of such institutions show that many of their inmates
+are mentally subnormal. The proportions range from thirty-three per cent.
+in the New Jersey Reformatory at Rahway to eighty-nine per cent. in the
+institution at Geneva, Illinois.</p>
+
+<p><b>Institutional Figures Misleading.&mdash;</b>However, significant as are these
+figures from institutions for delinquents, one should not be misled by
+them. They are undoubtedly not representative of offenders in general, but
+of a selected group of the most hopeless cases. In the first place the
+more capable individuals escape the dragnet which lands the defective
+delinquents in an institution, and furthermore, because of liberal systems
+of probation, only the more incorrigible or the very stupid make up the
+bulk of the population of such places. Miss Augusta F. Bronner, assistant
+director of the Psychopathic Institute of the Juvenile Court of Chicago,
+from a careful study of five hundred and five cases of delinquent boys and
+girls in the Detention Home, chosen with as little selection as possible,
+finds the proportion of mentally subnormal among them to be less than ten
+per cent.</p>
+
+<p><b>Many Prisoners Mentally Subnormal.&mdash;</b>Doctor Walter S. Fernald, of the
+Massachusetts School for Feeble-minded, estimates that &#8220;at least 25 per
+cent. of the inmates of our penal institutions are mentally defective.&#8221;
+Among the various available estimates at hand this seems to be a fairly
+conservative approximation. Hastings H. Hart points out that this
+calculation of 25 per cent. means that there are 20,000 adult defective
+delinquents in prison, and 6,000 youths in<span class="pagenum"><a name="Page_267" id="Page_267">[Pg 267]</a></span> juvenile reformatories, or a
+total of 26,000 in custody in the United States.</p>
+
+<p><b>The Inhibitions Necessary to Social Welfare Not Well Established in
+All.&mdash;</b>But let us look at this matter of delinquency a little more in
+detail. In common with other living creatures mankind has two strongly
+predominating instincts without which there can be no prolonged individual
+or racial existence, namely, the self-preservative and the reproductive.
+Says Schiller: &#8220;While philosophers are disputing about the government of
+the world, Hunger and Love are performing the task.&#8221; Under
+self-preservative would be included everything pertaining to food,
+property and self-protection. In addition, however, man, together with
+certain other social animals, has developed a third set of activities or
+instincts&mdash;an impulsion toward the preservation of the community to which
+he belongs&mdash;and so far has this evolved in his case that it outranks in
+importance the other two. For the highest accomplishments and ideals of
+the race are in last analysis expressions of this social instinct. But
+with this system of mutual help comes the necessity of certain restraints,
+because for society to exist its members must impose upon themselves, or
+have imposed upon them, certain inhibitions of their self-preservative and
+reproductive instincts.</p>
+
+<p>Being a late acquisition of the race and less firmly ingrained, the social
+instinct is not well established in all individuals. Some have it
+sufficiently strong to exercise of their own accord the necessary
+inhibitions of other instincts. Experience has shown that others, either
+through a lack or through a wrong cultivation<span class="pagenum"><a name="Page_268" id="Page_268">[Pg 268]</a></span> of it, can not or will not
+do so unaided. For the latter, society has instituted certain conventions
+and the criminal law whereby through a system of restraints and
+punishments such an individual is held in check either by actual physical
+restraint of his property or person or through the powerfully inhibitive
+factors of shame or fear. Man as a normal member of society must
+constantly take heed of the physical, intellectual or moral danger the
+exercise of a given feeling, action or procedure on his part will bring to
+humanity, and govern himself accordingly.</p>
+
+<p>But it is in just these very inhibitions that mental defectives are
+lacking. They are almost invariably anti-social types because they are
+unable to establish the personal abstentions which are necessary for the
+good of the community. While in the individual of innate normal mentality
+anti-social traits may have developed because of improper training or
+surroundings, in mentally defective types some factor or factors necessary
+to normality have been left out of their make-up and as a result they are
+often wholly lacking in social instincts or have these so feebly developed
+that education and exhortations toward social ideals are fruitless. We can
+not appeal successfully if there is nothing to appeal to; we can not
+develop something out of nothing.</p>
+
+<p><b>The High-Grade Moron a Difficult Problem.&mdash;</b>One great difficulty in
+identifying the high-grade morons who are a bountiful source of our
+criminals is our almost universal failure to recognize that a memory test
+alone is not sufficient to determine the mental responsibility of an
+individual. Not only memory, but<span class="pagenum"><a name="Page_269" id="Page_269">[Pg 269]</a></span> judgment, will-power and perhaps, also,
+to a lesser degree, the powers of attention and concentration are all
+indispensable elements in the make-up of a normal individual. There are
+cases on record of imbeciles with prodigious memories, yet hopelessly
+incapable of caring for themselves or of respecting the rights of others.
+In fact certain types of morons, usually cunning, often prepossessing and
+superficially clever, are characterized by good memories and will
+<i>moralize</i> volubly, although their wills are too weak to inhibit impulses
+when they face temptation. It is obvious that just in proportion as the
+intelligence of the high-grade degenerate approaches normality and yet
+remains abnormal, the more dangerous he may become to society.</p>
+
+<p><b>Degenerate Strains.&mdash;</b>A number of family records are now available which
+show convincing evidence of the hereditary nature of a degeneracy which
+finds expression in pauperism, immorality and crime.</p>
+
+<p>As has already been pointed out, there is reason to believe that much of
+this is based in some degree on feeble-mindedness. One of the most
+remarkable of these is the recent study on degeneracy by Goddard as set
+forth in his book called <i>The Kallikak Family</i>. The record is that of six
+generations of descendants from an original progenitor to whom the
+fictitious name of Kallikak has been assigned. This individual, descended
+from good stock, before his marriage met a feeble-minded girl by whom he
+became the father of a feeble-minded son. Later he married a normal woman
+by whom he had normal children. Thus from one normal father have sprung
+two lines of progeny, one vitiated with feeble-mindedness, the other
+normal.<span class="pagenum"><a name="Page_270" id="Page_270">[Pg 270]</a></span> The comparison may be readily made by drawing up in parallel
+columns the data as follows:</p>
+
+<table border="0" cellpadding="0" cellspacing="0" summary="table">
+<tr><td align="center"><span class="smcap">Line A</span></td>
+    <td><span class="spacer">&nbsp;</span></td>
+    <td align="center"><span class="smcap">Line B</span></td></tr>
+<tr><td>In five generations 480 direct<br />descendants from a normal father<br />father and a feeble-minded<br />mother have been accounted for<br />as follows:</td>
+    <td>&nbsp;</td>
+    <td valign="top">In five generations 496 descendants<br />from the same normal father as in<br />Line A and a normal mother have the<br />following record:</td></tr>
+<tr><td>&nbsp;</td></tr>
+<tr><td valign="top">143 known to be feeble-minded.</td>
+    <td>&nbsp;</td>
+    <td valign="top">All but one of normal mentality.</td></tr>
+<tr><td>&nbsp;</td></tr>
+<tr><td valign="top">291 mental status unknown or<br />doubtful.</td>
+    <td>&nbsp;</td>
+    <td valign="top">Two men known to be alcoholic.</td></tr>
+<tr><td>&nbsp;</td></tr>
+<tr><td valign="top">36 illegitimate.</td>
+    <td>&nbsp;</td>
+    <td valign="top">One case of religious mania.</td></tr>
+<tr><td>&nbsp;</td></tr>
+<tr><td valign="top">33 sexually immoral, mostly<br />prostitutes.<br /><br />24 confirmed alcoholics.</td>
+    <td>&nbsp;</td>
+    <td>Among the rest have been found<br />nothing but good representative<br />citizenship, numbering doctors,<br />lawyers, educators, judges,<br />traders, etc.</td></tr>
+<tr><td>&nbsp;</td></tr>
+<tr><td>3 epileptics.</td>
+    <td>&nbsp;</td>
+    <td>No epileptics or criminals.</td></tr>
+<tr><td>&nbsp;</td></tr>
+<tr><td>82 died in infancy.</td>
+    <td>&nbsp;</td>
+    <td>Only fifteen children died in infancy.</td></tr>
+<tr><td>&nbsp;</td></tr>
+<tr><td>3 criminals.</td></tr>
+<tr><td>&nbsp;</td></tr>
+<tr><td>8 keepers of disreputable houses.</td></tr>
+<tr><td>&nbsp;</td></tr>
+<tr><td>46 only ones known to ben ormal.</td></tr></table>
+
+<p>Certainly there is abundant food for thought in these two records.</p>
+
+<p>If we take still other families of criminal or degenerate antecedents the
+same multiplication of viciousness, as a rule, is in evidence. Thus,
+<i>Margaret, the Mother of Criminals</i>, has left a progeny of some 700
+paupers, prostitutes and criminals, some of the women bearing as many as
+twenty children. The famous Jukes family, so often cited, with its 310
+professional paupers, 300 deaths in infancy, 440 physical wrecks from
+debauchery, 50 prostitutes, 60 habitual thieves, 7 murderers, and 130
+other convicts out of a total 1,200 descendants who have been identified,
+has alone cost the<span class="pagenum"><a name="Page_271" id="Page_271">[Pg 271]</a></span> state of New York $1,250,000 in the care of its
+criminal, defective and immoral progeny.</p>
+
+<p>Another family record, the Zeros, reported by Poellman, of Bonn, starts
+with a female confirmed drunkard. In six generations of her descendants,
+totaling 800 people, Poellman found 102 professional beggars, 107
+illegitimates, 181 prostitutes, 54 in almshouse, 76 convicted of serious
+crime, 7 of murder, and costing some $1,206,000. Or we might cite the
+so-called <i>Tribe of Ishmael</i>, the progeny of a neurotic man and a
+half-breed woman. They have spread their ill-favored spawn over various of
+the central states in a veritable flood of imbecility and petty crime. And
+to these families may be added the records of <i>The Hill Folk</i>, <i>The
+Pineys</i>, or others of the several recent studies of degenerate strains.
+All bear the same message of rapidly multiplying degeneracy.</p>
+
+<p><b>Intensification of Defects by Inbreeding.&mdash;</b>Most of these regional surveys
+that are now in progress show that there is particular danger in a
+population becoming broken up into small communities and isolated. Under
+such conditions there is a pronounced tendency to intermarry, and if
+deterioration is already present in the stock such communities become
+centers of marked degeneracy. The situation is well exemplified in the
+following excerpt from Davenport:</p>
+
+<div class="blockquot"><p>&#8220;I have been going over the records of one family in New York, the
+so-called Nam family. There were 55 per cent. consanguineous matings,
+marriage between cousins, in one generation, and, owing to the fact
+that the strain was already loaded with defects, we can see how these
+defects were concentrated by these cousin <span class="pagenum"><a name="Page_272" id="Page_272">[Pg 272]</a></span>marriages, so that about 90
+per cent. of the strain is feeble-minded. There were fully 90 per
+cent. of the men who are unable to resist the lure of liquor.
+One-fourth of the children are born illegitimates. Infanticides,
+incest, murder, harlotry, are all over the chart. This is a highly
+inbred community, keeping a nearly pure strain of social defects, and
+the cost to the community has been a million and a half on a fair way
+of figuring, not directly in the care, but indirectly in the damage
+they have done. These constitute a rural community. Out of this
+community we can trace those who have gone to the cities and become
+murderers, prostitutes and thieves. They are not confined to one
+state; they spread out over the country. One branch of the family came
+to the state of Minnesota. We sent to one of Doctor Rogers&#8217; trained
+field workers to learn whether she had ever heard of this family, and
+received a reply that the family was well known to social workers in
+the state of Minnesota. These strains of degenerates are not local
+matters at all; they are matters of national interest.&#8221;</p></div>
+
+<p>Concerning crime and delinquency, we find that all evidence tends to show
+that an alarming increase is in progress although satisfactory data are
+hard to obtain. It is certain that there is a tremendously
+disproportionate increase in the number of prisoners in recent years
+compared with general population, for while the total population has
+increased three and one-half fold, the prison element has increased
+fifteen fold. According to Wier, in this country there are four and
+one-half times as many murders for every million of our population to-day
+as there were twenty years ago.</p>
+
+<p>It may be urged that this increase in prison population is not a
+disproportionate increase in the number of defectives or criminals, but
+only an increase in the<span class="pagenum"><a name="Page_273" id="Page_273">[Pg 273]</a></span> number sent to prison, and this is probably a
+partial truth&mdash;but when we recall such pedigree as those of the Nams, the
+defective line of Kallikaks and other known unsound strains, he must be
+hopeful indeed who can find much consolation in this supposition. In any
+event, no such uncertainty exists regarding the number of murders and
+homicides, since these have in all probability been as fully recorded in
+the past as at present.</p>
+
+<p><b>Vicious Surroundings Not a Sufficient Explanation in Degenerate
+Stocks.&mdash;</b>It is sometimes urged that we are not dealing in such cases with
+degenerate strains, but merely with unfortunate individuals who have been
+subjected to pernicious surroundings from the beginning. And it can not be
+denied that parents who are mentally defective, dissipated or syphilitic
+afford most noxious developmental and environmental conditions for their
+children. But when one notes how intimately the moral degeneracy in such
+stocks is bound up with some degree of feeble-mindedness, he is strongly
+skeptical toward the sufficiency of such an interpretation, although
+environment undoubtedly intensifies the results. Concerning this point
+Davenport says:</p>
+
+<div class="blockquot"><p>&#8220;We have certain methods of testing whether it is bad environment or
+bad breeding which produced these people. Some of the children have
+been taken at an early age and &#8216;placed out&#8217;. We have traced their
+subsequent history. In most cases they have turned out quite as bad as
+those who have remained at home. In a few cases they have turned out
+well, but it is also true that some of the children who remained at
+home in bad environment have turned out well.&#8221;</p></div>
+
+<p><span class="pagenum"><a name="Page_274" id="Page_274">[Pg 274]</a></span>And to Davenport&#8217;s testimony may we add that of Doctor Wilmarth, who,
+speaking of children at the home for feeble-minded, says:</p>
+
+<div class="blockquot"><p>&#8220;In no place is this subject of the power of heredity in relation to
+environment so easily studied as among our children. A group of many
+little children came to us from the state school, being untrainable
+there. They have had with us the same teaching and the same
+companionship. Each one has lived, eaten and slept among the others,
+and, so far as we know, with but one exception, those of vicious
+parentage have turned instinctively to vicious traits by preference,
+while those of simple but honest stock do evil things only under
+strong temptation, and do not persist in them after the wrong is
+pointed out.&#8221;</p></div>
+
+<p><b>By No Means All Delinquents Are Defectives.&mdash;</b>One must not overlook the
+fact, however, that <i>delinquent</i> and <i>defective</i> are by no means
+synonymous terms, and that many delinquents are with little doubt the
+product of adverse social circumstances.</p>
+
+<p>The recent careful work of Doctor William Healy<a name='fna_13' id='fna_13' href='#f_13'><small>[13]</small></a> in connection with the
+juvenile delinquents of Chicago shows convincingly that the underlying
+causations of delinquency are many. Such factors as immorality or constant
+quarreling of parents, bad companions, lack of parental control, defective
+sense organs, debilitating habits, lack of healthy mental interests and a
+host of other environmental factors are not infrequently sufficient in
+themselves to develop delinquency in the absence of inherited deficiency.
+The present-day efforts<span class="pagenum"><a name="Page_275" id="Page_275">[Pg 275]</a></span> of the student of heredity should not be
+misunderstood. They are not attempts to make all delinquents out
+defectives, but rather to determine what percentage of delinquents may be
+legitimately reckoned as defective and to make the facts known. Since
+there is no longer any reasonable doubt that, to express it in the mildest
+terms, an amount of delinquency far from negligible is due in great
+measure to congenital omissions or propensities, then the sooner the
+public learns this the better, for we may then set about supplementing our
+present efforts at race betterment through external improvement by
+devising means of cleansing the fountain source as well.</p>
+
+<p>It can scarcely be doubted that the average man differs little if any in
+inherent personality and capacity from many a criminal who is such by
+occasion rather than by undue predisposition. Who can truthfully answer
+how many individuals there are who are not potentially criminals to some
+extent, given sufficient evocative conditions of ignorance, vice, adverse
+economic pressure and undue temptation?</p>
+
+<div class="blockquot"><p>&#8220;Virtue itself turns vice, being misapplied.&#8221;</p></div>
+
+<p><b>No Special Inheritable Crime-Factor.&mdash;</b>The main difficulty in trying to
+find a hereditary basis for crime lies in the multiplicity of things crime
+may be. The individual impulsions which lead to certain offenses may be
+utterly different from those which conduce to others. Undoubtedly many
+inborn tendencies which are perfectly normal or neutral in themselves may
+be warped by circumstances into the commission of what<span class="pagenum"><a name="Page_276" id="Page_276">[Pg 276]</a></span> are classified as
+crimes. The moral man may have the same desire for a thing that the
+criminal does, but when he finds that this desire can only be gratified by
+injury to others, he inhibits it because of his repugnance to such injury.
+The criminal makes no such inhibition.</p>
+
+<p>In general, crime means an offense of some kind against person, property
+or state. But a biological analysis of it, could it be made, would require
+among other things knowledge of crime in terms of motive or lack of
+motive, whether the act was intended to benefit the perpetrator, some
+other person, or even the race or state; whether the offense was one of
+dishonesty, of cupidity, of lust, or of violence against another.</p>
+
+<p>As a matter of fact no satisfactory classification of crime can be made
+since so many factors enter and in such varying degrees. Most
+classifications made in our legal codes are a hodge-podge based on a
+mixture of motive on the part of the participant, degree of turpitude
+involved, nature and extent of the injury inflicted, and the object
+against which the offense was perpetrated, whether an individual, society
+or the state. Moreover, it must not be forgotten that in many instances
+what was crime in the past is no longer so, and vice versa many things
+which are regarded as criminal to-day were not considered so in the past.
+So the futility of seeking a specific inherent propensity for &#8220;crime&#8221; is
+manifest. How, for instance, in terms of hereditary determiners shall we
+draw the fine lines of distinction among those who bribe legislators and
+legal officials, those who are avaricious and dishonest<span class="pagenum"><a name="Page_277" id="Page_277">[Pg 277]</a></span> in the world of
+trade, and those who are wilfully obtuse in providing proper safeguards
+for employees?</p>
+
+<p><b>What Is Meant by a Born Criminal?&mdash;</b>All we can do is to fall back on the
+assurance that any act directly or indirectly injurious to society is an
+offense, and that those offenders who are congenitally unable to
+distinguish between what is generally accepted as right and wrong, or who
+if recognizing this are nevertheless uncontrollably impelled toward or are
+unable to refrain from anti-social acts because of some inherent condition
+of intellectual or volitional make-up, may be legitimately classed as
+individuals born with an aptitude for crime and social transgressions. In
+such individuals the natural mental make-up is lacking in some of its
+necessary elements so that memory, judgment, or will-power are not up to
+the minimum that is necessary for the establishment of proper conduct. In
+some cases, apparently, this lack finds expression in almost any kind of
+vice or crime into which circumstances happen to lead the individual. In
+others, however, there seem to be tendencies toward the commission of
+certain types of crime or vice. Certain family strains are characterized
+by petty thieving, others by deeds of violence, and still others by sexual
+offenses. Certain types of mental defect are closely associated with
+certain crimes. Thus sufferers from incipient paresis seem particularly
+prone to commit assaults and larceny; epileptics, crimes of brutality and
+violence.</p>
+
+<p><b>The Epileptic Criminal Especially Dangerous.&mdash;</b>One of the characteristics
+of epilepsy, indeed, emphasized by various psychiatrists, is that
+frequently it<span class="pagenum"><a name="Page_278" id="Page_278">[Pg 278]</a></span> leads to loss of those forms of self-restraint which are
+absolutely indispensable to morality and the safety of society. Cruelty,
+atrocious sexual offenses and other vicious crimes are the result. It is a
+noteworthy fact, moreover, that often in the milder forms of affliction,
+where instead of well-marked convulsions only momentary lapses of
+consciousness occur, the greatest amount of mental and moral deterioration
+and fluctuation is sometimes found.</p>
+
+<p>The situation as regards the epileptic is well presented by Doctor William
+Healy, Director of the Juvenile Psycopathic Institute of Chicago, in an
+article entitled &#8220;Epilepsy and Crime; the Cost&#8221;, in the <i>Illinois Medical
+Journal</i>, November, 1912. He says:</p>
+
+<div class="blockquot"><p>&#8220;In the work of our institute,<a name='fna_14' id='fna_14' href='#f_14'><small>[14]</small></a> which represents the most
+thoroughgoing research into the genetics of criminalism ever
+undertaken in this country, we have with the help of parents and
+others carefully studied nearly 1,000 young repeated offenders. We
+have found that no less than 7&#189; per cent. of these are ordinary
+epileptics, and we have reason to suspect others. This by no means
+represents the total number of epileptics seen in connection with
+juvenile court work, where, of course, first offenders as well as
+large numbers of dependents are seen. In addition to my above
+enumeration, other cases seen by the Detention Home physicians and
+myself amount up to many scores of cases. If one remembers that it is
+ordinarily calculated that one person in every 500 is epileptic, the
+significance of this high criminal percentage is clear, and the
+practical bearing of it is still further accentuated by the fact that
+some of the worst repeaters are epileptics, and that many of the
+gravest crimes are committed by <span class="pagenum"><a name="Page_279" id="Page_279">[Pg 279]</a></span>those unfortunates. The connection
+between epilepsy and crime has everywhere been recognized by students
+of the subject, but it apparently needs constant emphasis in order
+that common sense steps may be taken toward guardianship of these who
+suffer from a disease which wreaks such extravagant vengeance on
+society.&#8221;</p></div>
+
+<p><b>Mental Disorders Most Frequently Associated With Crime.&mdash;</b>Doctor Charles
+Mercier, an English authority on crime and insanity, in enumerating the
+mental disorders most frequently associated with crime, places the
+insanity of drunkenness first. Any one who will take the trouble to verify
+the facts in his own community will find that a large percentage,
+frequently considerably over half, of the arrests made by the police are
+for acts committed while the offender was more or less under the influence
+of alcohol. Next to drunkenness among mental disorders which lead to crime
+Doctor Mercier places feeble-mindedness. Next to feeble-mindedness comes
+epilepsy; then paranoia or systematized delusion; next paresis; and lastly
+melancholia.</p>
+
+<p>Paranoics are peculiar in that they are particularly apt to attack persons
+of prominence. Highly egotistical, they almost invariably believe
+themselves or some one or some cause dear to them, the subject of a plot,
+perhaps to rob them, to torture them, to steal their inventions or
+literary productions, or to persecute them in some way. Two if not three
+of our murdered presidents owe their assassinations to paranoics. Many
+rulers have been attacked and some killed by such insane individuals. Most
+of the &#8220;cranks&#8221; who write threatening letters are lunatics of this type.</p>
+
+<p><span class="pagenum"><a name="Page_280" id="Page_280">[Pg 280]</a></span>Of the kinds of mental unsoundness known to be inheritable which are of
+special significance from the standpoint of crime and delinquency
+undoubtedly feeble-mindedness ranks first. We have already seen that as
+our methods for detecting the higher grades of feeble-mindedness become
+more accurate we disclose in border-line cases a veritable hot-bed of
+mental incapacity suitable for the engendering of the criminal and the
+vicious. Here in addition to some of the more pronounced criminal types
+belong hosts of our chronic petty offenders, our sexually vicious and our
+&#8220;won&#8217;t-works&#8221;. One interesting outcome of a recent investigation into the
+army of unemployed in England was the discovery of the general unfitness
+of these unemployed. In our own country the habitually unemployed are so
+not because of lack of work, but largely because it is unprofitable to
+employ them.</p>
+
+<p><b>The Bearing of Immigration on Crime and Delinquency.&mdash;</b>Perhaps in no field
+more than this of crime and delinquency, especially in so far as it is
+based on innate deficiency, does the gravity of the immigration question
+impress itself on us. How stupendous this problem<a name='fna_15' id='fna_15' href='#f_15'><small>[15]</small></a> has become may be
+realized from the fact that according to the census of 1910, 13,345,545,
+or one out of seven of the inhabitants of the United States, were foreign
+born. And if we add to these the 18,897,837 of whom one or both parents
+were of foreign birth, we reach the astonishing total of over 32,000,000,
+or more than one-third of<span class="pagenum"><a name="Page_281" id="Page_281">[Pg 281]</a></span> our total population, who are foreign born, or
+who have one or both parents of foreign birth.</p>
+
+<p>During the decade from 1900 to 1910, 8,500,000 foreigners came to the
+United States, of whom 5,250,000 remained to make a permanent home. This
+shows how rapidly our whole population might be radically changed. In
+recent years the source of our immigrants has shifted proportionately from
+northwestern Europe to southern and eastern Europe (Italy, Austria-Hungary
+and Russia), and whether for weal or woe this new blood must inevitably
+leave its impress upon us. Does it not behoove us then to seek with
+anxious eyes some knowledge of these invading hordes with whom we are to
+mingle our life-blood?</p>
+
+<p>Even the most superficial examination may well cause us grave concern. We
+find that in one year (1908) at Ellis Island alone, 3,741 paupers, 2,900
+persons with contagious disease, 184 insane, 121 feeble-minded, 136
+criminals, 124 prostitutes and 65 idiots were denied entrance, and yet,
+according to the estimate of Doctor F. K. Sprague, of the United States
+Public Health Service, probably only about 5 per cent of the mentally
+deficient and 25 per cent. of those who will become insane have been
+detected. When confronted by such data we can begin to realize what we are
+facing. Others estimate that from 6 to 7 per cent. of the immigrants who
+are now arriving are feeble-minded. We learn further that recently while
+the foreign-born population of New York state was about 30 per cent., the
+foreign-born population of the insane hospitals of the state was over 43
+per cent., and at<span class="pagenum"><a name="Page_282" id="Page_282">[Pg 282]</a></span> one time approximately 65 per cent. for New York City.
+In one year (1908) 84 per cent. of the patients in Bellevue Hospital, New
+York City, were of foreign parentage. Paresis, which probably always has
+syphilis as its antecedent, is proportionately twice as prevalent among
+foreigners as among natives in New York City.</p>
+
+<p>But from the standpoint of inheritance, however great the danger may be
+from classifiable defectives, it is probably far greater from that much
+larger class of aliens we are now receiving with open arms who are below
+the mental and physical average of their own countries. Moreover, with our
+present system of inspection there is no way of detecting the grades of
+feeble-mindedness above idiocy and imbecility in the great numbers of
+foreign children under five when brought in, who are beginning to show up
+in alarming numbers in the schools of some of our larger cities. About
+thirty per cent. of the annual increment of our population is due to
+immigration and not to births; and once in our country the alien far
+outbreeds the native stock, with relatively little increase in death-rate,
+thus making a double contribution to the increase of population. When we
+take all these facts into consideration it certainly is high time that we
+arouse from our self-complacent attitude and consider the whole question
+of immigration most earnestly.</p>
+
+<p>In spite of the fact that many individuals are caught in the net of
+inspection at our portals, it is clear that still more rigid rejection<a name='fna_16' id='fna_16' href='#f_16'><small>[16]</small></a>
+is imperative. The inspectors<span class="pagenum"><a name="Page_283" id="Page_283">[Pg 283]</a></span> at our various ports are doing the best
+they can under the circumstances, but there are at present too few of them
+and they are too restricted in their powers to meet the situation
+satisfactorily. Moreover, when at one of our ports in one year (1910), of
+1,483 immigrants certified by the inspecting surgeons as unfit to land
+because of serious mental or physical defects, 1,370 were landed anyway,
+it is evident that there is a strong and reprehensible pull somewhere to
+evade the obvious intent of the law.</p>
+
+<p>It remains for us as a people to decide whether we shall continue to let
+the large employers of cheap labor, the railroad and steamship agents and
+brokers, who care nothing about the innate fitness of the immigrants they
+bring, determine the character of our future population, or whether we
+shall insist on a proper regulation of this flood so that we may receive
+only an honest, intelligent, industrious and healthy stock. To continue to
+absorb these aliens with as little selection as we now do is nothing short
+of criminal carelessness. Let us not be deceived by the promptings of a
+misguided sentiment, &#8220;The voice is Jacob&#8217;s voice, but the hands are the
+hands of Esau.&#8221; The voice is Jacob&#8217;s voice, nor should this voice of the
+easily persuaded, the sentimentalist, the interested organization to which
+the relatives of the defective alien belong, or any other pressure move us
+from our obvious duty of refusing to fasten upon this country an incubus
+of degeneracy for which we as a nation are in no way responsible.</p>
+
+<p>To render us safe we should not only have more carefully drawn laws and
+more rigid selection at our<span class="pagenum"><a name="Page_284" id="Page_284">[Pg 284]</a></span> ports of entry, but we should if possible
+also know the stock from which our future citizens come. This is
+peculiarly desirable for such defects as feeble-mindedness and various
+other mental imperfections, some of which require prolonged observation
+for detection. Davenport estimates that it is wholly within the realm of
+possibility and good business sense to maintain a corps of trained
+inspectors abroad in the chief centers from which our immigrants come who
+shall certify the desirable applicants. He makes the point that the
+national expense would be far less than the cost of maintaining the army
+of defectives we are now admitting to our own country, many of whom almost
+immediately become public charges, to say nothing of the hordes of
+carriers who though normal themselves, will transmit undesirable traits.</p>
+
+<p><b>Sexual Vice.&mdash;</b>As to sexual vice, the skein is indeed a tangled one. Since
+nine-tenths of the difficulty centers in a lack of self-restraint, and
+inasmuch as the mating instinct is one of the strongest that tugs at the
+flesh of humanity, it is obvious that those by nature deficient in
+volitional control will almost without exception give way to the call. So
+as might be expected the hordes of our feeble-minded and epileptic are
+always a source of grave danger in this respect. However, the mentally
+enfeebled are by no means the only offenders; indeed, they are probably
+not the majority. The true situation is finally dawning on society and the
+reformer&#8217;s call for instruction in &#8220;sex-hygiene&#8221; resounds through the
+land. The whole matter is one of the most perplexing and momentous that
+confronts us to-day.</p>
+
+<p><span class="pagenum"><a name="Page_285" id="Page_285">[Pg 285]</a></span><b>The Question of School Instruction in Sex-Hygiene.&mdash;</b>While the writer does
+not for an instant underestimate the gravity of the situation, and has
+only contempt for the nonsense that is palmed off on children about their
+origin, or the indelicate self-consciousness which puts under the ban the
+discussion of so serious a problem by adults, still he is not convinced
+that the universal teaching of the subject to children in schools by the
+average teacher, as advocated by some, is to be the solution of the matter
+or is even a wise attempt at solution. Yet he freely admits that he is
+possibly overfearful of the effects of the undesirable features of such
+instruction. True it is that all children do learn, frequently at an
+astonishingly early age, about sex, and their knowledge is usually of an
+undesirable kind from unreliable and often vicious sources, and it is
+equally true that parents, either through ignorance or prudery, generally
+can not be depended on to give the child necessary instruction. But before
+entering on a wide-spread campaign of undiluted sex-instruction in schools
+might it not be more prudent to make an attempt toward reaching fathers
+and mothers and convincing them of the necessity of dealing more frankly
+and intelligently with their children regarding sex?</p>
+
+<p>Even to the novice in psychology the powerful nature of suggestion is
+known, and with this knowledge before us, is it not wiser to strive in the
+main to keep the child&#8217;s mind off of sex rather than specifically to focus
+it on it by special convocations and discourse? If our psychology means
+anything, then the worst possible thing we can do for a child is to make
+him unduly<span class="pagenum"><a name="Page_286" id="Page_286">[Pg 286]</a></span> sex-conscious. Something might be done profitably perhaps in
+schools in an unobtrusive way by specially gifted persons, but the
+self-conscious way in which most teachers go about topics of sex is
+certainly not reassuring to the thoughtful observer as regards the benefit
+derived from such instruction. The one evident method of accomplishing
+wholesome sex-instruction in schools, devoid of all possibility of
+undesirable suggestion and sex-consciousness, is in the form of biological
+work where plants and animals are studied in all their relations, the
+subject of propagation being taken up in as matter-of-fact a way as the
+functioning of any other organ system of plants or animals. In such a
+course, long before the subject of sex in higher animals need be
+approached the pupil will have developed an attitude of mind which will
+lead him to see nothing unusual or suggestive in the function of sex no
+matter where it may be found. Incidentally, inasmuch as the manner in
+which germs affect living organisms should be studied in such a course
+anyway, it would be a simple matter to give all necessary information
+about the dangers of infection from venereal diseases.</p>
+
+<p><b>Mere Knowledge Not the Crux of the Sex Problem.&mdash;</b>However, desirable as
+correct knowledge about sex is, knowledge alone is not the crux of the sex
+problem. The moral dangers and abuses that we are trying to circumvent lie
+rather in the realm of the emotions than that of the intellect. The
+problem must be solved from a broader foundation than mere information.
+The all-important consideration is the early establishment of general
+habits of self-control<span class="pagenum"><a name="Page_287" id="Page_287">[Pg 287]</a></span> so that these may become incorporated in the
+nervous organization of the child and become inhibitory anchors against
+passions and temptation. Children must be taught to suppress the present
+impulse, to sacrifice the immediate pleasure for the more distant or
+permanent good. They must be practised in calling up feelings that will
+counteract other promptings which if followed blindly are inimical to
+social welfare. Their control must come from within not as a matter of
+external compulsion. That way character lies.</p>
+
+<p>So in viewing the problem of sexual hygiene the writer feels that our
+attempts toward damming the torrents in the adolescent by a belated effort
+at verbal instruction on sex-hygiene is at best only a palliative or an
+attempt to cure the symptoms of a more deeply-seated, organic, social
+malady. The treatment should have been in progress long before in the form
+of training in self-control, and in the inculcation of the sense of
+dignity and self-respect which springs from the individual&#8217;s consciousness
+of being, not a slave to his desires, but his own master. This, together
+with the judicious schooling of boys in a greater chivalry and respect for
+womanhood, and of girls in the necessity of meriting such esteem, will, in
+my estimation, carry us further than formal courses in sex-hygiene.</p>
+
+<p><b>Early Training in Self-Restraint an Important Preventive of Crime and
+Delinquency.&mdash;</b>As to crime and delinquency in general, it is evident that
+the same early training in self-restraint is a most important factor of
+prevention. A wise warden in charge of a large prison says, &#8220;Most of these
+men are here because they have not learned sufficiently the lesson of<span class="pagenum"><a name="Page_288" id="Page_288">[Pg 288]</a></span>
+self-control.&#8221; This is the age of preventive medicine, why not also of
+preventive crime and delinquency? Instead of confining our practise to
+punishing offenders, necessary as this may be under the present
+conditions, why not strive more to prevent the commission of offenses? As
+far as normal individuals are concerned much can be done by early
+cultivation in self-discipline and through the establishment of moral
+backbone by training in the overcoming of difficulties. Much, very much,
+also remains to be done in the correction of wrong social conditions.</p>
+
+<p><b>Unpardonable to Permit Delinquent Defectives to Multiply Their Kind.&mdash;</b>As
+for our mental defectives and moral imbeciles, knowing now how strongly
+hereditary the underlying factors of these conditions are, and with no
+preventive or curative agents in sight, to let them produce progeny, is
+clearly unpardonable.</p>
+
+
+
+<p>&nbsp;</p><p>&nbsp;</p>
+<hr style="width: 50%;" />
+<p><span class="pagenum"><a name="Page_289" id="Page_289">[Pg 289]</a></span></p>
+<h2><a name="CHAPTER_X" id="CHAPTER_X"></a>CHAPTER X</h2>
+<p class="title">RACE BETTERMENT THROUGH HEREDITY</p>
+
+
+<p>Most of us have heard in one form or another the fairy story of the youth
+on adventure bent, who was captured by the giant and under dire penalty in
+case of failure was set the task of sweeping out the giant&#8217;s stable before
+sundown. The peculiarity of this stable, it will be recalled, was that, as
+fast as the refuse was swept out at the door an even greater quantity
+poured in through the windows so that the sweeper, just in proportion to
+his zeal, became more and more encumbered with his burden.</p>
+
+<p><b>A Questionable Form of Charity.&mdash;</b>Though we smile at the childishness of
+this legend, are we not as a civilized people attempting through our
+charities a feat parallel to that of this unfortunate youth? We foster and
+favor our social wastage with the inevitable result that it runs riot
+under our sheltering hand and deluges us with an ever accumulating flood
+of its like. For are we not constantly building more asylums, sanitaria
+and prisons, to preserve more unfit, to produce more defectives, to
+require still greater numbers of asylums, sanitaria and prisons, to
+preserve more unfit, and so on in unending progression?</p>
+
+<p>At nearly every period of history there have been<span class="pagenum"><a name="Page_290" id="Page_290">[Pg 290]</a></span> certain individuals who
+have seen the necessity of a state eliminating its supply of defectives.</p>
+
+<p><b>Past Protests.&mdash;</b>For instance, we find the importance of this strongly
+urged by Plato. After pointing out the fact that the shepherd, in order to
+maintain the standard of his flocks, bred only from the best individuals,
+as did likewise the huntsman with his dogs and horses, and the fancier
+with his various pets, Plato went on to show the danger to the state of
+allowing the constantly increasing body of defectives and degenerates to
+multiply their kind. Repeated expression of the same idea has occurred
+from time to time during the succeeding centuries.</p>
+
+<p>Little heed was paid to these remonstrances, however, with the result that
+is known to us all. To-day, &#8220;the glory that was Greece and the grandeur
+that was Rome&#8221; is still sung by the poet, but the original nations
+themselves have long since passed into the night.</p>
+
+<p><b>An Increasing Flood of Defectives.&mdash;</b>Strive to ignore the unpleasant facts
+as we may, we have to admit that the same problem of what the human
+harvest shall be is with us in grave form to-day. The alarming phase of
+the situation, however, lies in the fact that we are facing an ever
+increasing flood of social wastage.</p>
+
+<p>But <i>why</i> this increase of defectives? It can not be attributed to
+oppression, to grinding poverty, or to decline in attention to our sick
+and needy, for never was prosperity greater, never were charities more
+flourishing, never such activity in the search for palliatives and cures.
+The simple fact is that we are breeding our defectives. The human harvest
+like the grain<span class="pagenum"><a name="Page_291" id="Page_291">[Pg 291]</a></span> harvest is based fundamentally on heritage. And to get a
+better crop of human beings, we must, as with other crops, weed out bad
+strains.</p>
+
+<p>To whatever source of information we turn the facts are essentially the
+same. Abroad we find that in England, for example, the ratio of defectives
+to normals more than doubled between 1764 and 1896. At home, from the
+investigation of Davenport and Weeks we learn that in the state of New
+Jersey the number of epileptics doubles every thirty years. And other
+investigators estimate that the fecundity of mental defectives in general
+is about twice as great as that of the average of our population. In a
+recent report of the New York State Board of Charities we read, &#8220;There are
+about thirty thousand feeble-minded persons in the state of New York, of
+whom four thousand are intermittently sequestered while twenty-six
+thousand who are a menace to society are at liberty and may produce the
+unfit.&#8221; And a passage from the last Massachusetts report reads as follows:
+&#8220;We have been obliged to refuse a very large number of applicants for the
+admission of feeble-minded women&mdash;many of whom have given birth to one or
+more children. The prolific progeny of these women almost without
+exception are public charges from the date of their birth.&#8221;</p>
+
+<p>How fertile defective types may be is shown by a passage in one of Doctor
+Wilmarth&#8217;s papers which runs as follows: &#8220;One feeble-minded woman, now
+removed from this state, had by different men eighteen children in
+nineteen years, she alleges.&#8221; In a letter Doctor Wilmarth tells me that
+the birth of the twenty-third<span class="pagenum"><a name="Page_292" id="Page_292">[Pg 292]</a></span> child of this woman has just been
+announced! In one English workhouse Potts reports sixteen feeble-minded
+women who have produced one hundred sixteen mentally defective children,
+and Branthwaite ninety-two female habitual drunkards who have had eight
+hundred fifty babies. If we include the two million individuals cared for
+annually in various institutional homes, hospitals and dispensaries as
+dependents, the estimated total of insane, feeble-minded, epileptic, deaf
+and dumb, criminals, juvenile delinquents, paupers and other dependents in
+the United States in 1910 was approximately three million, or one in every
+thirty of our population! With the higher fertility of certain of these
+classes and with only a small percentage under custodial care where will
+it all end? Is it not time for us to waken from our lethargy and stem this
+tide of national deterioration?</p>
+
+<p><b>Natural Elimination of Defectives Done Away With.&mdash;</b>With our improved
+methods of sanitation and care of the sick, the pauper and the defective,
+these classes have been freed from the stress of an environment that under
+natural conditions would have resulted in their premature death and
+consequent infertility. Or in the terminology of the biologist, we have
+done away with the factor of <i>natural selection</i>, the factor which in
+state of nature keeps all races purged of the unfit, the ill-adapted. With
+this restraining, and purifying influence removed, however, the weakling,
+the defective, may arrive at maturity and commingle his blood with that of
+the strong, with the inevitable result that the general vigor of the
+progeny from generation to generation is sapped and<span class="pagenum"><a name="Page_293" id="Page_293">[Pg 293]</a></span> progressively
+undermined. Thus we are confronted by the stubborn fact that through
+present humanitarian methods we are driving the race toward decadence.</p>
+
+<p><b>Why Not Prevent Our Social Maladies?&mdash;</b>Now there is no reasonable person, I
+think, who will not admit that the motives underlying our modern
+altruistic practises are the noblest fruitage of our slow upward struggle
+from the brute to man. As humane beings, we can not cast aside these
+principles and return to the painful and pitiless method of nature which
+would leave the sick and the defective alone to perish miserably; the
+sacrifice would be too great.</p>
+
+<p>Is there then no escape from this dilemma? To this query the modern
+student of heredity answers yes; let us but add more wisdom to our charity
+and the enigma is solved. We need no sacrifice of pity but rather an
+expansion of it. Let us but extend our vision from immediate suffering to
+the prospective suffering of the countless unborn descendants of our
+present unfit and ask ourselves the question, why should they be born? Why
+not prevent our social maladies instead of waiting to cure them? This is
+the province of eugenics.</p>
+
+<p><b>Eugenics Defined.&mdash;</b>The term Eugenics was coined in 1883 by Francis Galton
+in his book entitled <i>Inquiries Into Human Faculties</i>, and we may
+therefore look to him for a satisfactory definition. He says, &#8220;Eugenics is
+the study of the agencies under social control, that may improve or impair
+the racial qualities of future generations, either physically or
+mentally.&#8221; And again, &#8220;I take Eugenics very <span class="pagenum"><a name="Page_294" id="Page_294">[Pg 294]</a></span>seriously, feeling that its
+principles ought to become one of the dominant motives in a civilized
+nation, much as if they were one of its religious tenets.... Man is gifted
+with pity and other kindly feelings, but he also has the power of
+preventing many kinds of suffering. I conceive it to fall well within his
+province to replace natural selection by other processes that are more
+merciful and not less effective. This is precisely the aim of Eugenics.
+Its first object is to check the birth-rate of the unfit instead of
+allowing them to come into being, though doomed in large numbers to perish
+prematurely. The second object is the improvement of the race by
+furthering the productivity of the fit, by early marriages and the
+healthful rearing of their children.&#8221;</p>
+
+<p><b>Improved Environment Alone Will Not Cure Racial Degeneracy.&mdash;</b>While many an
+enthusiastic humanitarian is laboring under the assumption that if we can
+improve external conditions human deficiencies will disappear, the student
+of heredity realizes that this is in large part a delusion unless we can
+secure an accompanying improvement in intrinsic qualities of the human
+species itself through the suitable mating of individuals. Just as the
+intelligent farmer to-day demands selected seed as well as good soil and
+proper cultivation, so one with the facts of heredity at hand would, as he
+views social problems, urge the fundamental importance of having selected
+stock with which to start. No shifts or shapings of environment will ever
+enable men to &#8220;gather grapes of thorns or figs of thistles.&#8221;</p>
+
+<p><span class="pagenum"><a name="Page_295" id="Page_295">[Pg 295]</a></span><b>Heredity and Environment.&mdash;</b>To wrangle over the question of which is the
+more important, heredity or environment, is about as idle a proceeding as
+to argue which is the more important, the stomach or something to put in
+the stomach. Man would soon come to grief without either. So, too, the
+question of human development is not one of heredity alone nor of
+environment alone; both are necessary and must work hand in hand. Dormant
+capacities must have proper environment to call them forth, but on the
+other hand no kind of environment can evoke responses if some degree of
+aptitude is not present.</p>
+
+<p>Professor Thorndike undertook experiments with groups of school children
+of high and of low initial ability respectively to determine whether equal
+opportunity or equal special training would produce an equalizing effect
+in easily alterable traits such as rapidity in addition and the like.
+Without exception he found that at the end of such experiments, although
+both groups had improved, the superior individuals were farther ahead than
+ever, that equality of opportunity and training had widened rather than
+narrowed the gap between the two classes. Others who have made special
+studies on the causes of individual differences have come to the same
+conclusion; namely, that individuals differ widely by original nature and
+that similarity in conditions of nurture and training will not avail in
+deleting these differences.</p>
+
+<p>Galton and others, from extensive studies based on English sources, have
+shown that notable achievements have run in certain families to a degree
+that is <span class="pagenum"><a name="Page_296" id="Page_296">[Pg 296]</a></span>inexplicable on the basis of opportunity alone; it can be fully
+accounted for only by attributing much to superior inborn capacity. Doctor
+Woods has shown much the same thing for certain families in America.
+Schuster and Elderton have proved that there is a high degree of
+similarity in scholastic standing between fathers and sons in Oxford.
+Professor Pearson&#8217;s measurements of mental characters in brothers and
+sisters while at school show a high degree of innate resemblance in many
+cases and certain cases of decided contrast. Where contrasts exist in
+certain families they remain unreduced in spite of the similarity of
+environment, thus proving that environment is less operative in the final
+intellectual establishment of such individuals than are their inborn
+aptitudes. Even in twins, as both Galton and Thorndike have shown, there
+is no tendency for similar education, home life and the like to render
+those originally different any more similar with advancing years.</p>
+
+<p>Professor Karl Pearson has done more perhaps than any other individual
+toward attempting actually to measure the relative strength of heredity
+and environment. Numerous statistical measurements lead him to conclude
+that it is a conservative estimate to regard heredity as at least five or
+ten times as important as environment in the development of the
+individual. A vigorous defense by him of this position will be found in
+<i>Biometrika</i> for April, 1914.</p>
+
+<p><b>Inter-Racial Marriage.&mdash;</b>Some of the dangers of racial deterioration which
+threaten us because of our laxity regarding immigration have already been
+indicated. It is high time that we give this whole <span class="pagenum"><a name="Page_297" id="Page_297">[Pg 297]</a></span>question the most
+serious consideration of which we are capable. From the rate at which
+immigrants are increasing it is obvious that our very life-blood is at
+stake. For our own protection we must face the question of what types or
+races should be ruled out. Aside from the dangers which lie in the
+defective or unsuccessful types already discussed in Chapter IX, many
+students of heredity feel that there is great hazard in the mongrelizing
+of distinctly unrelated races no matter how superior the original strains
+may be. Unfortunately there is a great lack of reliable data on this
+point. The mulatto of our own country, the Eurasians in India and the
+mixed races of South America are, according to the testimony of many
+observers, eloquent arguments against such hybridization. Agassiz remarked
+on this point as follows:</p>
+
+<div class="blockquot"><p>&#8220;Let any one who doubts the evil of the mixture of races and who is
+inclined from mistaken philanthropy to break down all barriers between
+them come to Brazil. He can not deny the deterioration consequent upon
+the amalgamation of races, more wide-spread here than in any other
+country in the world, and which is rapidly effacing the best qualities
+of the white man, the Indian, and the negro, leaving a mongrel
+nondescript type deficient in physical and mental energy.&#8221;</p></div>
+
+<p>Of the American mulatto one not infrequently meets with the assertion that
+he is on the average inferior mentally, morally and physically to either
+the white or the negro race. Thus Doctor J. B. Taylor<a name='fna_17' id='fna_17' href='#f_17'><small>[17]</small></a> states<span class="pagenum"><a name="Page_298" id="Page_298">[Pg 298]</a></span> that,
+&#8220;It is demonstrated by well-attested facts that these hybrids of black and
+white are vastly more susceptible to certain infections; their moral as
+well as physical stamina is lower than that of either original race.&#8221;
+Others would deny that conclusive evidence to this effect exists. However,
+it is certain that under existing social conditions in our own country
+only the most worthless and vicious of the white race will tend in any
+considerable numbers to mate with the negro and the result can not but
+mean deterioration on the whole for either race.</p>
+
+<p>There is certainly not one iota of evidence that the crossing of any two
+widely different human races will yield superior offspring in any respect
+and there are many indications that such intermixture lowers the average
+of the population. Our evidence derived from plant and animal breeding is
+also against pronounced crosses. The inferiority of the mongrel is
+universally recognized. No sane farmer, for example, would seek to improve
+his Jerseys or his Herefords by crossing one with the other. It is true
+that in pure breeds of plants and animals we sometimes venture on a cross
+to introduce some new desirable character but we follow up such mixture by
+a rigid selection in which is eliminated all but the rare individuals
+having the desired characteristics, and we continue this elimination
+generation after generation to fix our characters again. It is obvious
+that no such selection as this would be possible among the progeny of
+human crosses.</p>
+
+<p>It clearly becomes our duty then to determine as accurately as possible
+the degree of non-relationship between races it is inadvisable to
+transcend in <span class="pagenum"><a name="Page_299" id="Page_299">[Pg 299]</a></span>inter-racial marriages. We are certainly taking great risks
+in accepting in any considerable numbers those races we can not assimilate
+to advantage into our own stock.</p>
+
+<p><b>War.&mdash;</b>The deteriorating effect of war on national physique and vigor has
+been so frequently cited by eugenists<a name='fna_18' id='fna_18' href='#f_18'><small>[18]</small></a> and is so obvious as scarcely to
+require further comment. It should be pointed out, however, that where, as
+is the case at present in Great Britain, armies are assembled from
+volunteers, instead of by conscription, there is the greatest danger from
+the eugenic standpoint, since not only physical but moral qualities are
+involved. For it is the brave, the generous, the individual with a high
+sense of duty who goes forward to the slaughter leaving the cowardly, the
+selfish or the indifferent to father the race. With the awful deadliness
+of modern warfare upon exhibition before our very eyes to-day, the extreme
+seriousness of such selective action must be evident to every thoughtful
+person.</p>
+
+<p><b>Human Conservation.&mdash;</b>We talk much in recent years of <i>conservation</i>; but
+what are our forests and frontiers, our minerals and our waterways,
+compared with our national health and life-blood? No farmer would think of
+setting aside a diseased or physically defective <i>animal</i> for breeding
+purposes, yet the same man together with the majority of mankind is wholly
+oblivious to similar faults when it comes to the mating of human beings.
+But is it not as important to look to fitness in man as in Poland China
+hogs or Holstein cows? Certainly the various strains are as<span class="pagenum"><a name="Page_300" id="Page_300">[Pg 300]</a></span> marked and
+breed as true in the human family as in our live stock. Why face
+complacently in our own families what we would not tolerate in our
+piggery?</p>
+
+<p>From the expenditure of comparatively small sums in studying the
+inheritance of various qualities in wheat, corn and other grain,
+improvements based on the laws of genetics have been secured which are
+enormously increasing our agricultural output and thereby adding to our
+national wealth. But if it costs relatively little to discover and
+conserve millions of dollars&#8217; worth of hereditary qualities in our plants
+and animals, what are we to think of ourselves, an intelligent people who,
+knowing that &#8220;every good tree bringeth forth good fruit, but a corrupt
+tree bringeth forth evil fruit,&#8221; still go on placidly permitting the
+production of defectives and delinquents? Can we continue to drink the
+sluggish blood of the pauper and the imbecile into our veins and hope to
+escape unscathed?</p>
+
+<p>We are all familiar with the fate of Babylon, Assyria, Persia, Egypt and
+Rome. Why not America? Certainly we have no pledge of special immunity
+from Divine Powers. If so, what then is the meaning of our 366 hospitals
+for insane which cost us annually $21,000,000; our 63 institutions for
+feeble-minded costing us over $5,000,000; our 1,300 prisons maintained at
+a cost of more than $13,000,000; our 1,500 hospitals whose annual
+maintenance requires at least $30,000,000; our 115 schools or homes for
+deaf and dumb; our 2,500 almshouses with an annual expense account of
+$20,000,000 and our 1,200 refuge homes costing annually several millions
+of dollars more? To say that we spend annually over $100,000,000 on the
+<span class="pagenum"><a name="Page_301" id="Page_301">[Pg 301]</a></span>custody of insane, feeble-minded, paupers, epileptics, deaf, blind and
+other charges is expressing the situation very conservatively.</p>
+
+<p><b>Kindness in the Long Run.&mdash;</b>There is no one I think who will not admit that
+the sympathy and charity of the human heart are its noblest virtues. But
+we must face the problem of what is kindness in the long run. Havelock
+Ellis well says, &#8220;The superficially sympathetic man flings a coin to the
+beggar; the more deeply sympathetic man builds an almshouse for him so
+that he need no longer beg; but perhaps the most radically sympathetic of
+all is the man who arranges that the beggar shall not be born.&#8221;</p>
+
+<p>What shall we do?</p>
+
+<p><b>The Problem Has Two Phases.&mdash;</b>For an intelligent consideration of the
+problem one must recognize at the outset that it has two distinct phases;
+namely, (1) a selective union of the fittest, or in other words, a
+conscious attempt to breed a superior race; and (2) the elimination of the
+obviously unfit by preventing their reproduction, with the purpose of
+purifying the present race. It is evident at a glance that these are two
+essentially distinct problems although the practise of either method could
+result in racial improvement. The first is sometimes spoken of as
+<i>positive</i> or <i>constructive eugenics</i>, the second as <i>negative</i> or
+<i>restrictive eugenics</i>.</p>
+
+<p><b>Constructive Eugenics Must Be Based on Education.&mdash;</b>As to the first phase,
+direct selection for superiority, the campaign must, in the very nature of
+things, be one of education. With the necessary knowledge of the facts in
+mind, the awakening <span class="pagenum"><a name="Page_302" id="Page_302">[Pg 302]</a></span>conscience of the individual together with an
+enlightened public opinion will form the safest guide. Increasing popular
+comprehension of the inevitable nature of human inheritance must engender
+a sense of responsibility as to the positive eugenic fitness of a
+contemplated marriage. The growth of this sentiment will doubtless be
+slow, and properly so, for as yet we have but half-lights on what are the
+most desirable types of humanity. No one can say what the highest type of
+man should be, but almost any one can readily pick out types which
+certainly should <i>not</i> be.</p>
+
+<p><b>Inferior Increasing More Rapidly Than Superior Stocks.&mdash;</b>Modern eugenists,
+although realizing that the constructive phase is of great importance, are
+making no attempt to map out any fixed mode of procedure for it beyond
+pointing out the desirability of larger families among the better classes.
+The need for individuals of superior physical, mental and moral qualities
+to multiply is so obvious as scarcely to require comment. Yet the fact is
+that judging from all appearances these are the very ones who have the
+lowest birth-rate. Eugenics is mainly concerned with the relative rates of
+increase of the various classes, not with mere fertility in itself. And
+the actual increase must be measured in terms of the extent to which
+birth-rate exceeds death-rate. If a high birth-rate is accompanied by a
+high death-rate then it is not especially significant in increasing a
+given class as a whole. All available evidence points to the fact that
+to-day the lower strata of society are far outbreeding the middle and
+higher, with an almost negligible difference in death-rate, and just in
+the measure that these lower<span class="pagenum"><a name="Page_303" id="Page_303">[Pg 303]</a></span> strata are innately inferior just in that
+degree must the race deteriorate. The seriousness of the whole situation
+as it exists to-day hinges, therefore, on the extent to which the lower
+strata are inferior to those above them.</p>
+
+<p><b>An Unselected Population May Contain Much Valuable Material.&mdash;</b>In
+evaluating these lower strata a matter of very great importance is whether
+the population is a selected or an unselected one. If the population has
+been long resident in a given region and has had fairly good opportunity
+for education then we will find in the lower reaches a larger percentage
+of sedimentation made up of the worthless and inferior stocks. If,
+however, a continual fomentation and geographical shifting of the
+population is in progress as in parts of America, or if adequate
+educational opportunities are lacking, as in some parts of Russia, the
+poor and less well-to-do classes may contain, no one can tell how much,
+relatively valuable stock.</p>
+
+<p>Forel remarks on this point as follows:</p>
+
+<div class="blockquot"><p>&#8220;If we compare the nature of delinquents, abandoned children,
+vagabonds, etc., in a country where little or nothing has been done
+for the people (Russia, Galicia, Vienna, etc.), with that of the same
+individuals in Switzerland, for example, where much has already been
+done for the poor, we find this result: In Switzerland, these
+individuals are nearly all tainted with alcoholism, or pathological
+heredity; they consist of alcoholics, incorrigibles, and congenital
+decadents, and education can do little for them because nearly all
+those who have a better hereditary foundation have been able to earn
+their living by honest work. In Russia, Galicia, and even in Vienna,
+we are, on the <span class="pagenum"><a name="Page_304" id="Page_304">[Pg 304]</a></span>contrary, astonished to see how many honest natures
+there are among the disinherited when they are provided with work and
+education.&#8221;</p></div>
+
+<p><b>The Lack of Criteria for Judging Fitness.&mdash;</b>Barring the untold hordes of
+actual defectives who have gravitated into this lower stratum, there are
+few positive criteria by which we can measure the real fitness of the
+remainder. Before we can set out on a campaign of positive eugenics we
+must have some standard by which to steer, and it would be a rash advocate
+indeed who would assert that class distinction alone, or even success as
+measured by public opinion to-day should be our whole criterion of
+fitness. Shall we measure fitness in terms of how successfully one can
+acquire worldly goods, or in other words, by the property test, or what
+shall be our standard?</p>
+
+<p><b>The College Graduate.&mdash;</b>Many of our modern critiques of the birth-rate
+situation make much of the fact that our college graduates as a group are
+scarcely reproducing themselves. According to Davenport, Bryn Mawr College
+between 1888 and 1913 has graduated 1,193 bachelors of arts, but these
+women have produced up to January, 1913, only 263 girls to take their
+place in the next generation. He also points out that statistics on some
+of the graduate classes of Harvard of twenty years ago or earlier show
+that they are little more than maintaining themselves; thus one class of
+328 graduates twenty years later had produced 195 sons, and in another
+case a class of 278 individuals had produced, twenty-five years later, 141
+sons. Relatively similar statistics can be cited for other eastern
+colleges.</p>
+
+<p><span class="pagenum"><a name="Page_305" id="Page_305">[Pg 305]</a></span>All such cases of college graduates cited as especially deplorable
+declines in birth-rate are based on the assumption that these individuals
+are a particularly superior stock.<a name='fna_19' id='fna_19' href='#f_19'><small>[19]</small></a> But one might question this premise
+as a generalization. It may or may not be true. Are they superior or have
+they had mainly a combination of luck and incentive, luck in that their
+parents had sufficient means, acquired possibly through their own
+superiority, possibly not, to send them to college, and incentive derived
+from a fortunate environment which awakened a desire in them&mdash;or in their
+parents for them&mdash;for college education? Is the woolly-witted son of
+opulence, so abundant in our colleges to-day, who is boosted through by
+hook or by crook, of superior eugenical value to the alert eager boy&mdash;and
+his name is legion&mdash;destined for economic reasons to go to work at or
+before the completion of his high-school course, perhaps because of the
+very fact of an unlimited fecundity in his own family which necessitates
+his help for the general support?</p>
+
+<p>When one first learns of the declining birth-rate among college women and
+men he feels appalled, but immediately the question flashes up, if this is
+<i>the</i> superior stock, and up to date it has died out or is dying out
+rapidly, whence then this ever augmenting rush of young folk who fairly
+deluge our universities and colleges to-day? Does it not rather point to
+the fact that in our own country at least, the man who will<span class="pagenum"><a name="Page_306" id="Page_306">[Pg 306]</a></span> and can take
+a college education successfully is not so much the product of breeding
+from college men, but of a prosperity which leaves a sufficient surplus in
+the family exchequer to enable sons and daughters to go to college, and is
+it not reasonable to suppose that there is yet an abundant stock back of
+these who similarly await but the golden touch of opportunity? When we
+consider such men as Carlyle, Lincoln and a host of others who were not
+the sons of collegians, although we may be university pedigreed ourselves
+we can not but feel doubtful of the validity of a premise which takes a
+college stock unqualifiedly as having any considerable monopoly of innate
+superiority. After all, college can mean little more than opportunity, and
+the obtaining of such opportunity in this world of economic maladjustments
+and accidents of social position is too largely a matter of chance, at
+least in America, to stamp the possessors of these advantages, on this
+criterion alone, as of inborn superiority. Undoubtedly much that is
+intrinsically good now slumbers in the lower strata of society because of
+lack of favorable environment to call forth the latent possibilities.</p>
+
+<p><b>Native Ability, Independence and Energy Eugenically Desirable.&mdash;</b>Although
+we can not sift out with certainty the superior from the inferior in our
+normal population by the property test or the educational standard alone,
+it is undoubtedly true that, on the whole, native ability, independence
+and energy are present to a higher degree in our well-to-do and prosperous
+families than in the stocks which merely hold<span class="pagenum"><a name="Page_307" id="Page_307">[Pg 307]</a></span> their own or which
+gradually decline, and there is no gainsaying the fact that in so far as
+the lower classes are where they are through actual deficiency&mdash;and there
+are enormous numbers in this category&mdash;they threaten our very existence as
+a race. It is imperative that the great middle class in particular
+establish in some way a selective birth-rate, by increased fertility on
+their own part, and diminished fecundity on the part of inferior stocks,
+which will offset or more than offset the disproportionate increase of the
+socially unfit.</p>
+
+<p><b>Four Children to Each Marriage Required to Maintain a Stock.&mdash;</b>It is
+estimated that under present conditions an average of at least four
+children should be born to each marriage if a stock is to maintain its
+numbers undiminished. Some of our most valuable strains are falling far
+short of this average. In a statistical table on the relative fertility of
+different stocks, prepared by Pearson, we find the mentally defective,
+criminal, deaf-mute and degenerate stocks heading the list with averages
+ranging from five to seven children per family, while the American
+graduate (based on Harvard statistics) and the English intellectual types
+average less than two children per marriage. While the death-rate is
+higher in the undesirable classes mentioned, it is by no means enough
+higher to compensate for the difference in birth-rates. Thus while certain
+very desirable types are not maintaining themselves genetically, other
+extremely undesirable ones are rapidly more than replacing themselves.
+Investigations made by Heron in London show that this condition as regards
+English desirables did<span class="pagenum"><a name="Page_308" id="Page_308">[Pg 308]</a></span> not exist sixty years ago; then the richer a
+community was in professional men and well-to-do families, the higher was
+the birth-rate.</p>
+
+<p><b>Factors Contributing to Low Birth-Rate in Desirable Strains.&mdash;</b>Most
+students of the subject believe that the fecundity of much of the best
+blood in our country has reached such a low ebb as to threaten the whole
+fabric of our commonwealth. How to correct this is the pressing problem to
+which no one has found a solution. However much one may deplore it the
+fact remains that always in the history of the civilized world with the
+rise of material conditions in any class of a population there has come an
+accompanying limitation of child-birth. Explain this as we may in modern
+times&mdash;whether as an awakened individualism which looks only to the
+immediate interest of the individual as against the ultimate interest of
+the race, or a desire for luxuries or for a better opportunity for smaller
+numbers of children, or as a determined effort of the wage earner to
+better his conditions, or to the feminist movement with its accompaniment
+of a greater personal freedom of married women and the recognition of the
+fact that marriage and child-bearing are often bars to employment, or to
+general increasing pressure of economic burdens&mdash;in brief whatever the
+cause or causes, there is no denying the fact of a diminishing birth-rate
+among our abler men and women. Moreover, no amount of coaxing, cajoling or
+dire prophecy seems to avail in altering the conditions. Various partial
+remedies, many of them of questionable practicability, have been proposed,
+but so far there has been no far-reaching effort<span class="pagenum"><a name="Page_309" id="Page_309">[Pg 309]</a></span> made to put any of them
+into effect. It has been suggested that society return to the simple life
+so that our young folk may marry earlier and live more easily on limited
+means, but so far few volunteers have appeared to lead the procession.
+While there is no doubt that present economic conditions tend to penalize
+parenthood, the simple life will not return for the mere asking. It has
+been pointed out that the father is in unfair competition with the
+bachelor and is also unfairly taxed in comparison, and some would
+therefore tax unmarried men more heavily. Others would pay a direct bounty
+on reproduction, but it is probable that such rewards would merely
+stimulate families of the lower types to increased fruitfulness. And so
+one panacea after another may be weighed and found wanting.</p>
+
+<p><b>The Educated Public Must Be Made to Realize the Situation.&mdash;</b>It seems
+probable that the most success will be met with through the slow and
+unspectacular methods of education. The necessity of the situation must be
+driven home so that it becomes part and parcel of the collective
+intelligence of the educated public. Different ideals of life will have to
+be established in the young. If knowledge of the facts of heredity is
+thoroughly disseminated among the people and ideals regarding parenthood
+are fostered, then much will have been accomplished by the psychic power
+of suggestion alone toward the end desired.</p>
+
+<p><b>Utilization of Family Pride as a Basis for Constructive Eugenics.&mdash;</b>There
+are few more powerful incentives to make the best of one&#8217;s abilities, or
+few greater deterrents from vice than family pride; and<span class="pagenum"><a name="Page_310" id="Page_310">[Pg 310]</a></span> there is no
+reason why this same sentiment may not be aroused in behalf of unborn
+generations. The sentiment of caste or aristocracy in some form is well
+nigh universal in mankind. The family of Mr. A came over in the Mayflower
+and is therefore worlds above the family of Mr. B, who arrived fifty years
+later. Mr. X&#8217;s income is $5,000 a year, Mr. Y&#8217;s only $1,500. The poor
+family in the front suite of the tenement regards itself as far superior
+to the one in the rear. Among criminals the professional house-breaker
+feels himself to be of higher caste than the sneak-thief, and in turn is
+surpassed by the bank-burglar. Even in the insane asylum the feeling is
+rampant. With such a wide-spread tendency for a foundation the creation of
+a sentiment of eugenic aristocracy is by no means a visionary undertaking.</p>
+
+<p><b>The Tendency for Like to Marry Like.&mdash;</b>Even now there is a decided though
+unconscious tendency for like to marry like and thus create particular
+strains. We have lines, for instance, which produce notably families of
+scholars, others which yield mainly statesmen, and still other strains of
+inventors, of financiers, of naval men, of soldiers, and of actors
+respectively. And there is little doubt that people, with the facts of
+inheritance of ability once before them, will be led to act more or less
+in accordance with their knowledge. On the other hand, due apparently to
+the same unconscious tendency for like to marry like, we find produced
+criminalistic, feeble-minded, deaf-mute and tubercular stocks. The first
+type of family is often termed <i>aristogenic</i> and the second or defective
+type, <i>cacogenic</i>.</p>
+
+<p><span class="pagenum"><a name="Page_311" id="Page_311">[Pg 311]</a></span><b>Public Opinion as an Incentive to Action.&mdash;</b>Much of our social conduct is
+the result of the pressure of public opinion, yet so accustomed are we to
+this that we ordinarily do not feel it as a hardship. There is little
+doubt that similarly the more wholesome attitude toward parenthood
+advocated by the eugenist would be taken as a matter of course, once the
+idea became prevalent. It would come to be one of those socially
+preconceived ideas which are as much actualities and which become
+unconscious guides to action no less certainly than do the more obvious
+personal habits of the individual. And just in the degree that we as a
+race get the &#8220;feeling&#8221; that intellect, morals and skill are highly
+desirable attributes in marriage selection, just in that degree will one&#8217;s
+affections in their earlier stages gravitate toward individuals who
+possess such qualities in high degree. In the main, those stocks which
+have shown by ancestral as well as personal achievement their superiority
+will tend to insure most certainly a continuation of this superiority in
+offspring.</p>
+
+<p><b>Choosing a Marriage Mate Means Choosing a Parent.&mdash;</b>Although marriages, as
+all young folks know, are made in Heaven, it is interesting to see what a
+vast number of these foreordained matches coincide with propinquity in
+college, in church, or in the same social set. Moreover, children are born
+here on earth. The one thing of all things that the eugenist desires is
+for these young folk to get a clear-eyed vision of the fact that in
+choosing a marriage mate they are also choosing the future father or
+mother of their children with all that this implies.</p>
+
+<p><span class="pagenum"><a name="Page_312" id="Page_312">[Pg 312]</a></span><b>The Best Eugenic Marriage Also a Love Match.&mdash;</b>A few recent writers, who
+show an utter misconception of what the aim of modern eugenics is, have
+raised the cry of give us the old-fashioned love match instead of the
+eugenic marriage, as if the eugenist&#8217;s ideal of moral cleanliness, freedom
+from transmissible physical taints or mental enfeeblement, and an attitude
+of special approval toward marriages which bring together individuals of
+more than average mental or spiritual endowment, had anything in it that
+was inimical to love. No one better than he realizes the sordid depths to
+which marital relations devoid of mutual affection and regard must reach.
+Certainly there is nothing in the eugenic ideal when its full import is
+understood that can shock the sensibilities of the most delicate-minded.
+Indeed it is people of fine susceptibilities who will be the first to feel
+repugnance toward a marriage which means mental or physical deterioration
+of their own blood.</p>
+
+<p><b>Good Traits No Less Than Bad Ones Inherited.&mdash;</b>An inspection of such charts
+as those shown in Figs. 37, 38 and 39, <a href="#Page_313">pp. 313</a>, <a href="#Page_314">314</a>, <a href="#Page_316">316</a>&mdash;and an abundance
+of such encouraging records may now be found&mdash;reassures us in our
+convictions that good traits are no less inheritable than bad ones. And
+what any healthy, mentally well-endowed person may be depriving the world
+of if he or she declines to enter into a fruitful marriage can not be
+better exemplified than in the following excerpt from Davenport:</p>
+
+<div class="blockquot"><p>&#8220;Many a man at the opening of his life work vows, as Judge John Lowell
+of the middle of the eighteenth century did, as he was being graduated
+from Harvard <span class="pagenum"><a name="Page_313" id="Page_313">[Pg 313]</a></span>College, that he will never marry. But nature was too
+strong for John Lowell and he married three times, and among his
+descendants was the director of a great astronomical observatory, the
+president of Harvard College, a principal founder and promoter of the
+Massachusetts General Hospital and the Boston Atheneum; the founder of
+the city of Lowell and its cotton mills; the founder of the Lowell
+Institute at Boston; the beloved General Charles Russell Lowell and
+his brother, James, both of whom fell in the Civil War, and James
+Russell Lowell, poet, professor and ambassador; besides brilliant
+lawyers and men entrusted with large interests as executors of
+estates. Do you think John Lowell would have taken that vow could he
+have foreseen the future?&#8221;</p></div>
+
+
+<p>&nbsp;</p>
+<div class="figcenter"><img src="images/img35.jpg" alt="" /></div>
+<p class="center"><span class="smcap">Fig. 37</span></p>
+
+<p class="descrip">Pedigree of family with artistic (dark upper section), literary (dark
+right section) and musical (dark left section) ability (from Davenport).</p>
+<p>&nbsp;</p>
+
+<p><b>The Elimination of the Grossly Unfit Urgent.&mdash;</b>But even if, under present
+conditions of partial knowledge and lack of an adequate standard, the
+constructive phase of eugenics must be left in the main to the awakening
+conscience of the individual as humanity improves in general
+enlightenment, the second phase,<span class="pagenum"><a name="Page_314" id="Page_314">[Pg 314]</a></span> the elimination of the grossly unfit is
+one of the greatest social obligations that confronts us to-day. For if
+there is an alarming amount of mental impairment in civilized nations, and
+if the problems of pauperism, inebriety, prostitution and criminality are
+closely interwoven with the problems of mental unsoundness, as we have
+every reason to believe from available data, then any means which will
+operate toward securing normally functioning brains will at the same time
+operate toward diminishing, defects and delinquencies. And inasmuch as a
+considerable proportion of defects, both mental and physical, are
+inheritable, it is obvious that if we can diminish the number of children
+born into the world with defective brains or bodies we have made a long
+stride in the right direction.</p>
+
+<p>&nbsp;</p>
+<div class="figcenter"><img src="images/img36.jpg" alt="" /></div>
+<p class="center"><span class="smcap">Fig. 38</span></p>
+
+<p class="center">Inheritance of ability (from Kellicott after Whetham).</p>
+<p>&nbsp;</p>
+
+<p><span class="pagenum"><a name="Page_315" id="Page_315">[Pg 315]</a></span><b>Suggested Remedies.&mdash;</b>But how go about it? Various schemes have been
+proposed, of which the chief are as follows:</p>
+
+<div class="blockquot"><p>1. Laws restricting marriage.</p>
+
+<p>2. Systems of mating with the purpose of covering up and gradually
+diluting out defective traits.</p>
+
+<p>3. Segregation during the reproductive period.</p>
+
+<p>4. Sterilization.</p>
+
+<p>5. Education in the principles of eugenics.</p></div>
+
+<p><b>Inefficacy of Laws Which Forbid Marriage of Mental Defectives.&mdash;</b>The utter
+inefficacy of the first proposition, namely the enactment of laws
+restricting marriage, at least as regards the socially unfit whose
+condition is based on impaired mentality, has been demonstrated time and
+again. If they are forbidden marriage, they merely have children without
+getting married. Most states have laws to prevent the marriage of such
+individuals but these laws are almost wholly ineffective in preventing
+procreation on their part. We might as well recognize once for all that in
+such cases nothing short of close custodial care or sterilization will
+accomplish the end desired.</p>
+
+<p>As to the second proposition, systems of mating with the purpose of
+covering up and gradually diluting out defective traits, this has been
+shown to be possible with certain types of defectives. Whether it is
+desirable or not is a different question.</p>
+
+<p>&nbsp;<span class="pagenum"><a name="Page_316" id="Page_316">[Pg 316]</a></span></p>
+<div class="figcenter"><img src="images/img37.jpg" alt="" /></div>
+<p class="center"><span class="smcap">Fig. 39</span></p>
+
+<p class="descrip">Inheritance of ability (chart condensed and incomplete) in three markedly
+able families (from Kellicott after Whetham):</p>
+
+<p class="descrip">1, Charles Darwin; 2, his cousin, Francis Galton, founder of the modern
+eugenic movement.</p>
+<p>&nbsp;</p>
+
+<p><b>Systems of Mating Impracticable in the Main.&mdash;</b>By systems of mating, it
+should be said, is not meant the arbitrary marrying of two individuals
+willy-nilly, but rather it is the prevention from marriage of two
+individuals having similar defects. In general the facts at our command
+indicate that in the majority of cases the offspring from a marriage of an
+insane, feeble-minded or epileptic person with a normal individual free
+from all neuropathic taints are normal or at most show but slight effects
+of the taint. But what normal individual would knowingly marry into such a
+stock? With few exceptions such traits where inheritable are apparently
+negative, that is, not represented by some positive abnormal factor but
+due to the lack of some element or elements necessary to the proper
+working of the normal brain. In the offspring of such a union the
+necessary missing factors are supplied by the<span class="pagenum"><a name="Page_317" id="Page_317">[Pg 317]</a></span> normal parent. Or in
+Mendelian phraseology, the defective traits are recessive and are
+dominated by the normality of the other parent. Such offspring, however,
+while apparently normal of body are not normal of germ-plasm, inasmuch as
+half of their germ-cells will carry the abnormality of the defective
+parent as earlier explained (<a href="#Page_119">page 119</a>) under Mendelism. We have already
+seen (<a href="#Page_119">page 119</a>) how by continually marrying into strong strains the
+liability to recessive defect can be diluted out until the descendants are
+no more likely to have defective children than are members of our ordinary
+population. If, however, as is estimated in Bulletin No. 5 of the
+<i>Eugenics Record Office</i>, about thirty per cent. of our general population
+already carry recessive neuropathic taints, it certainly is a hazardous
+proceeding to attempt thus to breed out nervous defects unless one is
+absolutely sure of the normality of the strain into which it is proposed
+to marry. The great difficulty is in determining whether or not there is a
+defective ancestry in a given stock. We have at present no criteria for
+identifying normal individuals who have defective germ-plasm. As a
+practical test, however, if no defect has appeared in the stock for three
+or four generations back, the marriage would be relatively as safe as are
+the marriages of our average population to-day.</p>
+
+<p><b>Corrective Mating Presupposes Knowledge of Eugenics.&mdash;</b>But such a scheme of
+corrective mating presupposes a relatively high degree of intelligence and
+judgment on the part of the participants, and this is just what we do not
+have and in the nature<span class="pagenum"><a name="Page_318" id="Page_318">[Pg 318]</a></span> of things can not get, in the types of
+feeble-minded, epileptic and degenerate strains we are striving to
+eliminate. All our evidence shows that when unrestricted there is a marked
+tendency for feeble-minded to mate with feeble-minded, degenerate with
+degenerate. About sixteen per cent. of the feeble-minded, in fact, come
+from consanguineous marriages. If we try to legislate them into specific
+types of marriage then we encounter the same futility pointed out under
+our discussion of restrictive legislation, they will produce offspring
+without the formality of marriage.</p>
+
+<p>In certain cases of insanity and in other than neuropathic defects one can
+see how the system might be inaugurated with greater prospects of success,
+but even then a knowledge of the principles of eugenics would be necessary
+to the participants, or in other words we could only accomplish our end
+through our fifth proposition, education.</p>
+
+<p><b>Segregation Has Many Advocates.&mdash;</b>As to the third proposition, segregation
+during the reproductive period, this seems to have a larger number of
+advocates than any other coercive measure. While on theoretical grounds it
+is plausible enough, when we face the actual putting of the method into
+practise we are confronted by the fact that tremendous sums of money would
+be required to sequestrate and maintain colonies or industrial refuges.</p>
+
+<p>When one realizes that no state now provides for more than a small
+minority of its defectives, and knowing also of the pressure that must be
+brought to bear on legislatures to secure sufficient funds to provide for
+these cases of extremest urgency, one can not<span class="pagenum"><a name="Page_319" id="Page_319">[Pg 319]</a></span> be overly optimistic about
+the practicability of extensive sequestration.</p>
+
+<p>E. R. Johnstone, the superintendent of a large training school for
+feeble-minded in New Jersey, points out that no state in the Union is
+providing for many more than one-tenth of her feeble-minded and
+epileptics. If his estimate is true, to place in institutions, treat and
+train all its feeble-minded and epileptics would even now almost swamp any
+state treasury. But what <i>will</i> it be in the future if we permit this
+unrestricted nine-tenths to go on and multiply their kind?</p>
+
+<p>Leaving out of account the enormous sums spent in private charities even
+now from one-fifth to one-seventh the total public expenditures of almost
+any one of our states is going to maintain its defectives, dependents and
+criminals. From the 1912 report of the secretary of state, in the state of
+Wisconsin, for instance, I learn that of the total expenses for 1912,
+sixteen per cent. was for charitable and penal institutions. The situation
+is even worse in some other states. Think of it! Think what a large total
+of expense it becomes! And the expense is far secondary from the
+humanitarian standpoint to the misery involved.</p>
+
+<p>In the <i>Survey</i> of May 24, 1913, we find Mr. Hastings H. Hart, Director of
+the Department of Child Helping of the Russell Sage Foundation, proposing
+very specifically &#8220;a working program for the extinction of the defective
+delinquent,&#8221; which involves segregation during the reproductive period. He
+gives the number of feeble-minded under public care as 20,000 in
+institutions for the feeble-minded, 16,000 in almshouses, 5,000 in
+hospitals for the insane, and 26,000 in prisons<span class="pagenum"><a name="Page_320" id="Page_320">[Pg 320]</a></span> and reformatories, or a
+total of 67,000 already under custodial care. And he asserts that as
+nearly as can be judged, this is one-third of the feeble-minded persons in
+the United States.</p>
+
+<p>Between this estimate that one-third of our feeble-minded are in
+institutions and Doctor Johnstone&#8217;s that we are not providing for many
+more than one-tenth of our feeble-minded and epileptic, there is a wide
+discrepancy, but I know of no accurate data<a name='fna_20' id='fna_20' href='#f_20'><small>[20]</small></a> whereby the matter can be
+settled definitely. One point of difference may be that Doctor Johnstone
+specifically includes epileptics and another may be one of definition of
+feeble-minded. However, supposing that we could get them all into
+institutions, institutional care at present by no means also implies
+prevention of propagation. It is not an unusual history of feeble-minded
+women in our county poor-houses that they alternate between periods of
+housework in some family and periods of residence in the almshouse, the
+return to the latter being only too often to bear an additional child.</p>
+
+<p>Not a few students of the problem, however, advocate a rigid segregation
+as the only reasonable preventive measure, no matter what the expense.
+They point out that the cost is mounting up higher each year and that we
+are only increasing it ultimately by procrastination. They urge, moreover,
+that when counting<span class="pagenum"><a name="Page_321" id="Page_321">[Pg 321]</a></span> the cost of the segregation of the feeble-minded we
+should bear in mind also that we are reducing the expenses of our other
+charity and penal institutions, since much of degeneracy, pauperism and
+petty criminality centers in mental enfeeblement. Some believe that
+colonies can be established which are in considerable measure
+self-supporting. Doctor Johnstone, for instance, although his estimates of
+the number of feeble-minded and epileptic is one of the highest, sketches
+out in a recent paper (in <i>Pediatrics</i>, August, 1912) a plan which he
+considers feasible.</p>
+
+<p>But what assurance have we that we can prevent the production of
+defectives by segregation? In reply may be cited a recent experiment on an
+extensive scale. Cretinism is a condition due to disease of the thyroid
+glands. It is characterized by goiter, marked deformities and imbecility.
+It is hereditary and has been very prevalent in certain valleys of
+southern Switzerland and northern Italy. Cretin mated with cretin and
+consequently a large new supply was constantly produced. In recent years
+in certain communities the sexes have been segregated (see <i>Eugenic
+Review</i>, 1910, Jordan) with the result that in such places cretinism has
+about disappeared.</p>
+
+<p>Coming now to the fourth solution proposed, namely, sterilization,<a name='fna_21' id='fna_21' href='#f_21'><small>[21]</small></a> let
+us consider some of its alleged advantages and disadvantages.</p>
+
+<p><span class="pagenum"><a name="Page_322" id="Page_322">[Pg 322]</a></span><b>Sterilization.&mdash;</b>First of all, since there is some considerable popular
+misunderstanding on the subject, it should be made plain that by
+sterilization is not necessarily, nor in fact generally, meant
+asexualization, or the removal of the reproductive glands. On the
+contrary, in the male, sterilization is ordinarily accomplished by an
+operation known as <i>vasectomy</i>, in which a small piece of each sperm duct
+is removed. Such reports on it as I have found indicate that it is a
+comparatively simple minor operation which involves no special
+inconvenience or hardship on the subject beyond the deprivation of
+offspring. In fact, according to Doctor Sharp&#8217;s report, in the majority of
+cases where it has been put into practise the patient has usually
+submitted voluntarily after having the details of the situation explained
+to him and has often advised fellow delinquents to do likewise.</p>
+
+<p>Even should later developments show that a mistake had been made, in all
+probability the matter could be remedied by a second operation in which
+the cut ends of the ducts can be reunited. This has been accomplished
+experimentally in dogs, and furthermore, in men rendered sterile by
+occlusion of the duct through inflammatory diseases, the sterility has
+been remedied by removing the blocked area and reuniting the ends of the
+duct on either side.</p>
+
+<p>In women the corresponding operation&mdash;a section of the oviduct&mdash;is termed
+<i>salpingectomy</i>. Here, however, the operation is a more serious one as it
+usually involves opening the abdominal cavity and the accompanying hazard
+of infection, a danger sufficiently great<span class="pagenum"><a name="Page_323" id="Page_323">[Pg 323]</a></span> that it is safe to say that the
+operation will be resorted to more rarely than vasectomy in man.</p>
+
+<p><b>As a Eugenic Measure.&mdash;</b>Sterilization as a eugenic measure has many
+advocates and perhaps more opponents; and among the latter, it must be
+said, are many competent and thoughtful students of the subject who
+recognize existing conditions and deplore their continuance as much as any
+one. They maintain that while we may have to come to it as a last resort,
+we are yet too ignorant of the actual effects of the operation, or are too
+little informed on the inheritability of the specific traits we are trying
+to eradicate, to launch forth on so radical a program. We must not forget
+that when we put sterilization into effect we are going to have to deal
+with individual cases, not general averages.</p>
+
+<p><b>To What Conditions Applicable.&mdash;</b>And just here, it seems to me, is the crux
+of the situation. When confronted by the defective individual, in a
+practical case, just what criteria are we going to use to determine
+whether this particular individual should be sterilized or not? Nearly all
+of the twelve states which have sterilization laws specify insanity,
+feeble-mindedness, epilepsy and criminality.</p>
+
+<p><b>In Insanity.&mdash;</b>When it comes to insanity I strongly suspect that those who
+have the selection of the examining board will have difficulty in finding
+an alienist who is willing to take the responsibility of deciding on just
+which insane individuals shall be operated on and which not. For among the
+insane there are so many kinds and degrees of mental unsoundness,<span class="pagenum"><a name="Page_324" id="Page_324">[Pg 324]</a></span> and
+these are of such varying and as yet unknown eugenical significance, that
+a positive decision is frequently out of the question. Of the twenty-seven
+or more recognized forms of insanity who knows with any considerable
+degree of certainty which are heritable, which not? Shall we treat all
+manic-depressives alike? Shall we treat them as, for instance, we would
+those suffering from dementia precox? Who will take the responsibility of
+answering positively? Again, what shall we do in cases of paresis, or
+general paralysis of the insane, an affliction which probably invariably
+has syphilis as its antecedent? Yet it constitutes one of the commonest
+forms of insanity found in asylums. Doctor George H. Kirby, director of
+Clinical Psychiatry, Manhattan State Hospital, says that with one
+exception there are more admissions of paretics to Manhattan State
+Hospital than sufferers from any other form of mental disorder. He
+continues, &#8220;We find that when either the father or the mother suffers from
+paresis that many other members of the family may be infected with
+syphilis, and furthermore, we find that a surprisingly large number of
+children in these families are feeble-minded, nervous, or in other ways
+abnormal.&#8221; But here, it is clear, the patient has done the damage before
+he reached the hospital, nor was it paresis as such that did the harm but
+the syphilitic infection of which paresis itself was but the outcome.</p>
+
+<p>Certainly the one fact which stands out conspicuously when we face most
+concrete cases, is that at present we need more urgently than
+sterilization laws for the insane, exhaustive studies of the
+inheritability<span class="pagenum"><a name="Page_325" id="Page_325">[Pg 325]</a></span> of specific mental infirmities that we may know with some
+degree of certainty which warrant sterilization.</p>
+
+<p>Yet on the other hand one of the most disquieting facts that confronts us
+to-day is the large number of patients who are on parole from our
+hospitals for the insane, subject to recall. What shall we do with them?
+Shall we submit them to the tremendous hardship of still remaining under
+custodial care although to all intents and purposes sane, or shall we make
+their release contingent upon their submission to vasectomy or
+salpingectomy?</p>
+
+<p>In a few cases such as Huntington&#8217;s chorea (Figs. 26, 27, <a href="#Page_114">pp. 114</a>, <a href="#Page_116">115</a>) we
+can proceed with a fair degree of assurance, for we know that this
+dreadful malady is transmitted as a positive trait and that in all
+probability half of the children of an afflicted individual will inherit
+the defect. Such patients, if they ever rally sufficiently temporarily to
+leave the hospital, or where encountered outside the hospital should
+certainly be restrained from procreation. It is questionable if even their
+children, though apparently normal, should be allowed to have offspring,
+for usually the disorder does not manifest itself until middle life and
+then it is too late to try to prevent its transmission since the affected
+individual has already probably married and had children. But Huntington&#8217;s
+chorea is a comparatively rare form of insanity, and one of only a few
+about which our knowledge as regards its transmissibility is fairly
+satisfactory.</p>
+
+<p><b>In Feeble-Mindedness.&mdash;</b>When we come to institutions for the feeble-minded,
+however, there seems to be much more unanimity of opinion among
+physicians<span class="pagenum"><a name="Page_326" id="Page_326">[Pg 326]</a></span> in charge of such institutions that sterilization would be an
+effective and satisfactory disposition to make of many cases, if we are to
+release the patients in question from custody. Unquestionably in cases of
+imbecility it is easier than in insanities to pass conclusive judgment on
+the inheritability of the condition in a large class of cases. Practically
+all are agreed that either permanent custodial care through the
+reproductive period or sterilization should be enforced. Some maintain
+that such individuals should remain permanently in institutions anyway and
+that therefore to sterilize them is needless, while others urge that if
+sterilized many capable of making their own living could be freed and
+allowed to do so.</p>
+
+<p>According to Goddard the feeble-minded woman is about three times as
+likely to find a mate as a feeble-minded man, hence it would seem to be of
+much greater importance to sterilize the woman than the man.</p>
+
+<p>Again it might be urged with much justification, that even though
+sterilized, the feeble-minded individual because of lack of self-control
+will transgress sexually and will thus certainly become a menace to
+society in the spread of venereal diseases. If Mr. Hart&#8217;s estimate is
+anywhere near correct, that there are 60,000 feeble-minded women in the
+United States of child-bearing age, and that 13,000 are already in
+custody, then the task of getting all women of this class into custody is
+not so insurmountable as would at first appear.</p>
+
+<p><b>In Cases of Epilepsy.&mdash;</b>As to epilepsy, I find a very decided difference of
+opinion among physicians.<span class="pagenum"><a name="Page_327" id="Page_327">[Pg 327]</a></span> Some consider it, on account of its apparently
+strong inheritability, together with the shocking crimes perpetrated by
+epileptic criminal types, one of the most serious menaces, while others
+point out that we know nothing of the real cause of epilepsy, that there
+are all degrees and shades, that it is probably referable to different
+causes in different cases and that no one is able to say what the
+offspring of any given epileptic will be.</p>
+
+<p>As to criminal types, here again we face the difficulty of deciding any
+particular case. Let us suppose that twenty-five per cent. of criminals
+are mental defectives, how shall we sift them out from the seventy-five
+per cent. who are supposed to be eugenically normal? Doubtless in many of
+the twenty-five per cent. class, the indications of defective mentality
+are sufficiently evident to prevent mistakes, but a considerable number of
+uncertain status must also remain near the border-line.</p>
+
+<p><b>Sterilization Laws.&mdash;</b>Although twelve of our states already have
+sterilization laws, only two, Indiana and California, seem to have made
+any active attempt to enforce them. The situation is too new yet in
+Wisconsin, Michigan and Pennsylvania for these states to have shown what
+they intend to do. Although the Indiana law says, &#8220;it shall be compulsory
+for each and every institution&#8221; to maintain the practise, it has fallen
+into disuse since 1911, presumably because the governor believed the law
+unconstitutional. It is of interest to see the motive underlying the law
+in various states. In the majority it is purely eugenic. In Connecticut it
+is mainly eugenic though partly<span class="pagenum"><a name="Page_328" id="Page_328">[Pg 328]</a></span> therapeutic. In California it is
+apparently in part therapeutic, since it is stated as being for the
+physical, mental or moral benefit of inmates of various state
+institutions, and in part punitive and eugenic, since individuals twice
+committed for sexual offenses or three times for other crimes are subject
+to the operation.</p>
+
+<p>In Washington and Nevada the object is purely punitive, the persons
+specified being habitual criminals and persons adjudged guilty of carnal
+abuse of female persons under ten years of age, or of rape. In these
+states also the court orders the operation instead of leaving it to the
+decision of a board of medical experts.</p>
+
+<p><b>Social Dangers in Vasectomy.&mdash;</b>It has been urged against vasectomy that it
+will work untold harm because it relieves of the responsibility of a
+probable parentage. This argument does not appeal to one as very weighty
+as far as the imbecile or other degenerate is concerned, because one of
+the very traits characteristic of such individuals is lack of any sense of
+responsibility. By this same token, however, we have a very good argument
+for sequestration as against sterilization, for the degenerate, even
+though sterilized, will not be restrained sexually and will be likely to
+disseminate venereal diseases or commit rape. Furthermore, there will be
+the temptation to sterilize and liberate certain types that would
+otherwise have been kept permanently in custody.</p>
+
+<p><b>Our Present Knowledge Insufficient.&mdash;</b>When all is said and done, after we
+take into account the meagerness of our present knowledge on the subject,
+it is not to be wondered at that many thoughtful <span class="pagenum"><a name="Page_329" id="Page_329">[Pg 329]</a></span>students of a
+conservative turn of mind, feel that any considerable practise of
+sterilization is premature. The problem has so many phases, and despite
+occasional bits of positive knowledge, we are yet in such a sea of
+ignorance regarding it, that in no field is the good Friar Laurence&#8217;s
+admonition of &#8220;wisely and slow; they stumble that run fast,&#8221; needed more
+at present than it is here.</p>
+
+<p>There is little doubt that in theory the feeble-minded and similar
+defectives should be sent to institutions and kept there, but the
+important practical question is, can this be done? We can have no final
+answer until it is tried. While the initial expense would undoubtedly be
+great, if we could keep our defectives from propagation for a single
+generation we could very materially lessen their numbers and in succeeding
+generations the expenses of their care would rapidly diminish.</p>
+
+<p>The one crying need that stands out most prominently in this whole field
+is that of careful investigation of individual cases and specific types of
+malady, together with an accurate census of conditions as a whole. Our
+knowledge of individual malign heredities is too meager to carry us very
+far at present. When we have found after adequate investigation in just
+which specific types of defects heredity is an important factor&mdash;and we
+shall undoubtedly find it to be one in many cases&mdash;then we can proceed
+confidently with sterilization, if it will prove to be more practical and
+desirable than sequestration.</p>
+
+<p><b>Sterilization Laws on Trial.&mdash;</b>It will be of great interest and instruction
+to see how extensively, in the<span class="pagenum"><a name="Page_330" id="Page_330">[Pg 330]</a></span> various states which have recently passed
+sterilization laws, the experts selected will find it expedient to carry
+on sterilization, and what criteria they will use in deciding on
+individual cases. That sterilization can be put into effect is
+indisputable, as may be seen from the fact that several hundred operations
+have been performed in Indiana. If the board on whom the decision depends
+happens to be one which feels that many people are likely to distress
+themselves unduly over the border-line cases, and overlook the fact that
+there is always a goodly residue with which to proceed without great risk
+of mistake, then we may expect to see a vigorous campaign inaugurated, and
+those of us who are still undecided in the matter will have an opportunity
+of learning more certainly the merits or the failings of the scheme.</p>
+
+<p>Certain married degenerate types would seem to be the ones most urgently
+demanding attention. Having already begotten several defective children
+and with nothing else in prospect but the production of the same kind, it
+is difficult to see from any standpoint why a vasectomy on the male would
+not be a merciful act. There are not a few such families where the father
+is periodically in the hands of the law and yet not in permanent
+restraint. Once in custody his release could be made contingent on
+vasectomy.</p>
+
+<p><b>An Educated Public Sentiment the Most Valuable Eugenic Agent.&mdash;</b>Coming now
+to the last proposition, education of the public in the principles of
+eugenics, this is the method calculated to be of more far-reaching service
+than any other, in the negative as well<span class="pagenum"><a name="Page_331" id="Page_331">[Pg 331]</a></span> as in the positive phases of
+eugenics. Education is necessary before we can have effective restrictive
+measures for the mentally incompetent established and enforced, and it is
+also a prerequisite to intelligent procedure on the part of normal
+individuals in considering their own fitness for marriage.</p>
+
+<p>Of greatest importance in preventing undesirable marriages, as far as
+people of normal intelligence is concerned, will be the sentiment of
+disapproval which will arise on the part of society itself when it becomes
+really convinced that certain marriages are inimical to social welfare.
+Public opinion is, in fact, one of the most potent influences in marital
+affairs, simply because refusal to abide by the dictates of the community
+means social ostracism.</p>
+
+<p>That social disapproval of certain unions can become a very real factor in
+preventing such marriage is evinced on all sides by the numerous barriers
+to marriage already in existence based on race, religious sect or social
+status. Even in our much vaunted democracies one is looked down on who
+marries &#8220;beneath&#8221; his or her social set. This sentiment of taboo, so
+readily and often so senselessly cultivated in our present human society,
+will inevitably spring up in consequence of a wide-spread knowledge of the
+facts of human heredity. It is to such a growth, to the establishment of a
+disapproval which is the product of its own sentiments rather than to
+legislative enactments, that society must look for the greatest
+furtherance of the eugenic program.</p>
+
+<p>Necessary as legal restraint is in certain cases, it<span class="pagenum"><a name="Page_332" id="Page_332">[Pg 332]</a></span> must obviously be
+restricted to only the most glaring defects. Moreover, legislation can not
+run far in advance of public opinion.</p>
+
+<p><b>The Question of Personal Liberty.&mdash;</b>It must be admitted that there is a
+reluctance on the part of many even thoughtful individuals to the
+application of methods which savor in any way of restraint. An objection
+not infrequently urged by such persons against the application of certain
+eugenic principles is that they demand an unwarranted curtailment of
+personal liberty.</p>
+
+<p>To those who hoist the flag of personal liberty, it may fairly be asked,
+how much personal liberty does the syphilitic accord his doomed and
+suffering wife and children, or how much personal liberty is the portion
+of the offspring of feeble-minded parents? Or, what quota of personal
+liberty will accrue to the ill-fated descendants of the epileptic, the
+habitual drunkard or criminal, the gross moral pervert, the congenially
+deaf and dumb, or to even the progeny which may result from the union of
+two well-established tubercular strains?</p>
+
+<p>We do not hesitate to send the pick of our stalwart healthy manhood to war
+to be slaughtered by the thousands and tens of thousands when an affront
+is offered to an abstraction which we term our national honor, and,
+sublimely unconscious of the irony of it all, we throw ourselves into a
+well-nigh hysterical frenzy of protest when it is proposed to stop the
+breeding of defectives by infringing to a certain extent on their personal
+liberties.</p>
+
+<p>Society has already found it necessary to suppress<span class="pagenum"><a name="Page_333" id="Page_333">[Pg 333]</a></span> certain individuals
+and yet we hear little complaint about loss of personal liberty in such
+cases. But if it is necessary to restrain the man who would steal a purse
+or a horse, is it not still more urgent to restrain one who would poison
+the blood of a whole family or even of an entire stock for generations?
+Surely there can be but one answer; society owes it to itself as a matter
+of self-preservation to enforce the restraint of persons infected with
+certain types of disease and of individuals possessing highly undesirable
+inheritable traits, so that perpetuation of such defects is impossible.</p>
+
+<p><b>Education of Women in Eugenics Needed.&mdash;</b>One of the most crying needs of
+the present is the awakening and educating of women to the significance of
+the known facts. For they are perhaps the greatest sufferers, and once
+informed, as a mere matter of safety if for no other reason, they will see
+the necessity of demanding a clean bill of health on the part of their
+prospective mates. Furthermore in the last analysis woman is the decisive
+factor in race betterment, for it is she who says the final yea or nay
+which decides marriage and thus determines in large measure the qualities
+which will be possessed by her children. Above all, young women must come
+to realize that the fast or dissipated young man, no matter how
+interestingly or romantically he may be depicted by the writer of fiction,
+is in reality unsound physically, and is an actual and serious danger to
+his future wife and children.</p>
+
+<p><b>Much Yet to Be Done.&mdash;</b>But plain as is our duty regarding the application
+of facts already known, when<span class="pagenum"><a name="Page_334" id="Page_334">[Pg 334]</a></span> we consider that the student of heredity has
+made only a beginning, it is equally evident that he must be urged on in
+his quest for new facts, and the establishment of new principles. There is
+imperative need to carry on proper experiments with plants and animals, to
+collect necessary data regarding man, and for what is scarcely less
+important, the publication of the facts already acquired so that the
+public may be guided aright.</p>
+
+<p>Just at present it is of the utmost importance to secure more trustworthy
+statistics in order that we may intelligently go about instituting
+suitable restrictive measures for undesirable human strains. We must know
+the exact number and kinds of feeble-minded, epileptic and insane in our
+population, and we must have more insight into the personal status and
+pedigrees of our delinquents and criminals. For purposes of rational
+procedure such information is indispensable. Much can be done by
+hospitals, &#8220;homes&#8221; and penal institutions by determining and recording
+more accurately all obtainable facts regarding the ancestry of their
+charges. Moreover, in such states as Wisconsin, where the state hospitals
+for the insane have each an &#8220;after-care-agent,&#8221; the duties of such
+officers might well include the collection of more adequate data regarding
+the hereditary aspects of their patient&#8217;s condition. And lastly, if in
+every census, whether state or national, it were made an important part of
+the work to secure accurate vital statistics, particularly as they pertain
+to human heredity, the contribution toward enabling us ultimately to
+purge<span class="pagenum"><a name="Page_335" id="Page_335">[Pg 335]</a></span> the blood of our nation of certain forms of suffering, degeneracy
+and crime would be inestimably great.</p>
+
+<p><b>A Working Program.&mdash;</b>And now after reviewing at some length various aspects
+of man&#8217;s hereditary and congenital endowment, the important question
+arises as to whether it is possible, with the knowledge at present
+available, to go ahead with a practical program which will insure to the
+child of the future its right of rights, that of <i>being well-born</i>. When
+one considers the matter it is evident that much can be done at once. Most
+of the needs set forth in the preceding paragraph can clearly be met in a
+fair degree by instituting the procedures indicated.</p>
+
+<p>One of the obvious duties in a restrictive way that confronts us right at
+the start is the care and control of the feeble-minded and of the
+defective delinquent in such a way as to prevent procreation. Much help
+can be given also through intelligent agitation for the establishment of
+colonies for epileptics and the higher grades of feeble-minded which can
+be made in considerable measure self-supporting. A given colony must, of
+course, be for one sex alone. Much can be done, furthermore, by putting
+into operation, both in and out of institutions, effective systems of
+registering births and deaths together with accompanying facts which may
+prove of eugenical significance.</p>
+
+<p>Again, we should more surely identify and exclude undesirable immigrants
+and also undertake thoroughgoing investigations to determine which races
+we can not profitably assimilate into our own blood.</p>
+
+<p>Physicians should pay more attention to the hereditary<span class="pagenum"><a name="Page_336" id="Page_336">[Pg 336]</a></span> and congenital
+aspects of their cases and make it more a matter of conscience than they
+do at present to advise patients with regard to marriage. Prenuptial
+medical inspection should become the custom, if not by law at least as a
+voluntary procedure. Every parent must come to realize the grave risk to
+which he is subjecting his daughter if a guarantee of physical fitness,
+even more than assurance of financial standing or social position, is not
+forthcoming from her prospective mate.</p>
+
+<p>Wholly apart from the field of heredity though in a realm intimately
+concerned with the birthright of the child, much practical good can be
+accomplished by pondering the facts and the fictions of prenatal influence
+and in the light of the knowledge thus gained, seeing that while foolish
+and unnecessary worries are abolished, the conditions of health, nutrition
+and occupation surrounding the expectant mother are the best obtainable.
+It is the sacred duty of every individual, moreover, to see that the
+maximal possibilities of his own germ-plasm are not lowered by vicious or
+unwholesome living.</p>
+
+<p>As individuals we can cultivate a greater sense of responsibility
+regarding marriage and parenthood in those for whose training we are
+responsible. We can study this whole subject conscientiously, keep pace
+with new knowledge and see that other people are likewise informed. In
+showing an enlightened interest in the ideals of eugenics and a
+sympathetic approval of wholesome marriages, a sentiment toward parenthood
+will gradually arise which will make it seem more desirable to many worthy
+people than it does at <span class="pagenum"><a name="Page_337" id="Page_337">[Pg 337]</a></span>present. If we are of good stock ourselves we
+should recognize that it is highly desirable that we give to the race at
+least four children. On the other hand, if we come from a strain which is
+eugenically undesirable we should with equal conscientiousness refrain
+from contributing to human misery. For where serious obstacles to a union
+exist, renunciation is certainly a higher manifestation of love than is
+consummation of a marriage which will result in untold misery to the
+object of the affections. As a matter of fact, with adequate preliminary
+knowledge as to what actually constitutes a serious drawback to marriage,
+where such really exists and is recognized by the associated individuals,
+love of the kind that leads to marriage is not likely to arise.</p>
+
+<p>As has been suggested by various students of eugenics, it is even at
+present perhaps not infeasible for earnest individuals to start in a quiet
+way local centers for the keeping and filing of accurate records of their
+family traits for the future use of their descendants. Such groups,
+voluntary though they be, would soon acquire a degree of distinction that
+would make other people of good endowments wish to join in and go on
+record as eugenically desirable.</p>
+
+<p>Lastly, it should not be forgotten that good traits are inherited as
+certainly as bad ones. Moreover, in the realm of human conduct, even
+though the fundamental features of behavior are based on an inherited
+organization, man is not always driven by an inexorable linkage of
+inherited neutral units into only one line of conduct, since more or less
+capacity for alternative action is also inherited. It is the personal
+duty<span class="pagenum"><a name="Page_338" id="Page_338">[Pg 338]</a></span> of every member of society to aid in affording the opportunity and
+providing the proper stimuli to insure that out of the many possibilities
+of behavior which exist in the young at birth, those forms are realized
+which are best worth while to the individual and to society. And while we
+recognize that improved environment alone can not correct human
+deficiencies we must nevertheless not relax our efforts to get cleaner
+foods, cleaner surroundings, cleaner politics and cleaner hearts.</p>
+
+<p>Why go on alleviating various kinds of misery that might equally well be
+prevented? When one squarely faces the issue, surely the absurdity of our
+present practises can not but be evident to even the most thoughtless.</p>
+
+<p><b>Which Shall It Be?&mdash;</b>As a matter of social evolution, human homes
+originated in the necessity of an abiding place for the nurture and
+training of the young past their first period of helplessness. Well in the
+foreground of the mental picture which arises when we hear the very word
+<i>home</i>, are children. What shall the home of the future be with regard to
+its most important assets, the children? Shall we as a people continue to
+be confronted at every turn by the dull countenance of the imbecile, the
+inevitable product of a bad parental mating; or the feeble body and the
+clouded intellect of the child sprung from a parentage of polluted blood;
+or the furtive cunning of the born criminal, the will-less mind of the
+bred degenerate, or the shiftless spawn of the pauper? Or shall it be a
+type with laughing face, with bounding muscles, with<span class="pagenum"><a name="Page_339" id="Page_339">[Pg 339]</a></span> unclouded brain,
+overflowing with health and happiness&mdash;in short, <i>the well-born child</i>?</p>
+
+<p>The answer is in our own hands. The fate of many future generations is
+ours to determine and we are false to our trusteeship if we evade the
+responsibility clearly laid before us. How conscientiously we heed known
+facts, how actively we acquaint ourselves with new facts, and how
+effectively we execute the obvious duties demanded by these facts, will
+give us the answer.</p>
+
+
+<p>&nbsp;</p>
+<p class="center">THE END</p>
+
+<p><span class="pagenum"><a name="Page_340" id="Page_340">[Pg 340]</a></span></p>
+
+
+
+<p>&nbsp;</p><p>&nbsp;</p>
+<hr style="width: 50%;" />
+<p><span class="pagenum"><a name="Page_341" id="Page_341">[Pg 341]</a></span></p>
+
+<h2>GLOSSARY</h2>
+
+<p><span class="pagenum"><a name="Page_342" id="Page_342">[Pg 342]</a></span></p>
+
+
+<p>&nbsp;</p>
+<p><span class="pagenum"><a name="Page_343" id="Page_343">[Pg 343]</a></span></p>
+<p class="title">GLOSSARY</p>
+
+
+<p class="hang"><span class="smcap">Acquired Characters</span>, traits developed in the body through changes in
+environment or function, in contra-distinction to those which have their
+specific causes in the germ-cells.</p>
+
+<p class="hang"><span class="smcap">Adaptation</span> (L. <i>ad</i>, to; <i>aptus</i>, fit), fitness to environment.</p>
+
+<p class="hang"><span class="smcap">Albinism</span> (L. <i>albus</i>, white), a condition of deficiency in pigment.</p>
+
+<p class="hang"><span class="smcap">Allelomorph</span> (Gr. <i>allelon</i>, of one another; <i>morph&#275;</i>, form), one of a
+pair of alternate Mendelian characters.</p>
+
+<p class="hang"><span class="smcap">Ameba</span> (Gr. <i>amoib&#275;</i>, change), a primitive single-celled animal.</p>
+
+<p class="hang"><span class="smcap">Amphibian</span> (Gr. <i>amphi</i>, both; <i>bios</i>, life), capable of living both on
+land and in water.</p>
+
+<p class="hang"><span class="smcap">Anthropoid</span> (Gr. <i>anthropos</i>, man; <i>eidos</i>, form), man-like.</p>
+
+<p class="hang"><span class="smcap">Aristogenic</span> (Gr. <i>aristos</i>, best; <i>genesis</i>, origin), pertaining to the
+genetically most desirable human strains.</p>
+
+<p class="hang"><span class="smcap">Association Areas</span>, those regions of the brain in which presumably the
+higher mental processes are effected.</p>
+
+<p class="hang"><span class="smcap">Atavism</span> (L. <i>ad</i>, before; <i>avus</i>, grandfather), a return in one or more
+characters to an ancestral type. See <a href="#Page_8">p. 8</a> for restricted modern usage.</p>
+
+<p class="hang"><span class="smcap">Atrophy</span> (Gr. <i>a</i>, negative; <i>troph&#275;</i>, nourishment), a wasting away of a
+part of a living organism.</p>
+
+<p><span class="pagenum"><a name="Page_344" id="Page_344">[Pg 344]</a></span></p>
+
+<p class="hang"><span class="smcap">Axon</span> (Gr. <i>axon</i>, axis), the process from a nerve cell which becomes a
+nerve fiber.</p>
+
+<p class="hang"><span class="smcap">Binet-Simon Scale</span>, a series of tests graded to age and previous training
+of the average normal child, much used in measuring mental deficiency.</p>
+
+<p class="hang"><span class="smcap">Biology</span> (Gr. <i>bios</i>, life; <i>logos</i>, discourse), the study of life and of
+living things.</p>
+
+<p class="hang"><span class="smcap">Biometry</span> (Gr. <i>bios</i>, life; <i>metron</i>, measure), the study of biological
+problems by means of statistical methods.</p>
+
+<p class="hang"><span class="smcap">Blastomere</span> (Gr. <i>blastos</i>, germ; <i>meros</i>, part), one of the early cells
+formed by the division of the ovum.</p>
+
+<p class="hang"><span class="smcap">Blastophthoria</span> (Gr. <i>blastos</i>, germ; <i>phtheiro</i>, destroy), deterioration
+of the germ as the result of direct pathogenic or other disturbing agents.</p>
+
+<p class="hang"><span class="smcap">Blending Inheritance</span>, inheritance in which the characters of the parents
+seem to blend in the offspring.</p>
+
+<p class="hang"><span class="smcap">Cacogenic</span> (Gr. <i>kakos</i>, bad; <i>genesis</i>, origin), pertaining to genetically
+undesirable human strains.</p>
+
+<p class="hang"><span class="smcap">Cell</span>, the fundamental unit of structure in plants and animals.</p>
+
+<p class="hang"><span class="smcap">Centrosome</span> (Gr. <i>kentron</i>, center; <i>soma</i>, body), a small body which
+functions in indirect cell-division.</p>
+
+<p class="hang"><span class="smcap">Character</span>, any distinguishing feature, trait or property of an organism.</p>
+
+<p class="hang"><span class="smcap">Chemotropism</span> (chemical and tropism), defined, <a href="#Page_198">p. 198</a>.</p>
+
+<p class="hang"><span class="smcap">Chromatin</span> (Gr. <i>chroma</i>, color), deeply staining substance of the
+cell-nucleus.</p>
+
+<p class="hang"><span class="smcap">Chromosomes</span> (Gr. <i>chroma</i>, color; <i>soma</i>, body), characteristic deeply
+staining bodies, typically constant in number and appearance in each
+species of animal or plant, which appear in the cell during indirect division.</p>
+
+<p><span class="pagenum"><a name="Page_345" id="Page_345">[Pg 345]</a></span></p>
+
+<p class="hang"><span class="smcap">Chromotropism</span> (Gr. <i>chroma</i>, color; <i>trop&#275;</i>, turning), defined, <a href="#Page_198">p. 198</a>.</p>
+
+<p class="hang"><span class="smcap">Cleavage</span>, the division of the egg-cell into many cells.</p>
+
+<p class="hang"><span class="smcap">Congenital</span> (L. <i>con</i>, together; <i>gigno</i>, bear), present at birth.</p>
+
+<p class="hang"><span class="smcap">Conjugation</span> (L. <i>con</i>, together; <i>jugum</i>, yolk), the union of germ-cells
+or unicellular individuals for reproduction.</p>
+
+<p class="hang"><span class="smcap">Constructive</span> (or positive) <span class="smcap">Eugenics</span>, a system of securing a superior race
+through propagation of the fittest individuals.</p>
+
+<p class="hang"><span class="smcap">Cortex</span> (L. <i>cortex</i>, bark), the outer or investing layer of the brain.</p>
+
+<p class="hang"><span class="smcap">Cytoplasm</span> (Gr. <i>kytos</i>, cell; <i>plasso</i>, form), the protoplasm of the cell
+outside of the nucleus.</p>
+
+<p class="hang"><span class="smcap">Daltonism</span>, the commonest form of color-blindness in which the affected
+individual is unable to discriminate between red and green.</p>
+
+<p class="hang"><span class="smcap">Dendrites</span> (Gr. <i>dendron</i>, tree), branching processes which spring from
+nerve-cells.</p>
+
+<p class="hang"><span class="smcap">Determiner</span> (L. <i>determinare</i>, to determine), the distinctive cause or unit
+in a germ-cell which determines the development of a particular character
+in the individual derived from that cell. The terms <i>gene</i> and <i>factor</i>
+are sometimes used as synonyms of determiner.</p>
+
+<p class="hang"><span class="smcap">Dihybrids</span> (L. <i>di</i>, two; <i>hybrida</i>, mongrel), the offspring of parents
+differing in two characters.</p>
+
+<p class="hang"><span class="smcap">Diploid</span> (Gr. <i>diploos</i>, double; <i>eidos</i>, form), the dual or somatic number
+of chromosomes.</p>
+
+<p class="hang"><span class="smcap">Dominant Character</span> (L. <i>dominare</i>, to be a master), a character from one
+parent which manifests itself in offspring to the exclusion of a
+contrasted character from the other parent.</p>
+
+<p class="hang"><span class="smcap">Drosophila</span>, a genus of fruit-flies of which there are several species.</p>
+
+<p><span class="pagenum"><a name="Page_346" id="Page_346">[Pg 346]</a></span></p>
+
+<p class="hang"><span class="smcap">Duplex</span> (L. <i>duo</i>, two; <i>plico</i>, fold), the condition in which a character
+is represented by two determiners, one from each parent.</p>
+
+<p class="hang"><span class="smcap">Electrotropism</span> (Gr. <i>electron</i>, amber; <i>trop&#275;</i>, turning), defined, <a href="#Page_198">p. 198</a>.</p>
+
+<p class="hang"><span class="smcap">Embryo</span> (Gr. <i>embryon</i>), the young organism in its earliest stages of
+development.</p>
+
+<p class="hang"><span class="smcap">Embryogeny</span> (Gr. <i>embryon</i>; <i>genesis</i>, generation), the development of the
+embryo.</p>
+
+<p class="hang"><span class="smcap">Eugenics</span> (Gr. <i>eugenes</i>, well-born), the science relating to improvement
+of the human race through good breeding.</p>
+
+<p class="hang"><span class="smcap">Factor</span>, the determiner of a particular hereditary character.</p>
+
+<p class="hang"><span class="smcap">Feeble-Mindedness</span>, deficiency in mental development. For grades, see <a href="#Page_244">p. 244</a>.</p>
+
+<p class="hang"><span class="smcap">Fertilization</span>, union of the sexual cells.</p>
+
+<p class="hang"><span class="smcap">Fetus</span> (L. <i>feuere</i>, to bring forth), the unborn young animal in its later
+(after the second month in man) stages of development.</p>
+
+<p class="hang"><span class="smcap">Flagellum</span> (L. <i>flagellum</i>, little whip), a vibratile, thread-like organ of
+locomotion.</p>
+
+<p class="hang"><span class="smcap">Gamete</span> (Gr. <i>gamos</i>, marriage), a mature germ-cell.</p>
+
+<p class="hang"><span class="smcap">Genetics</span> (Gr. <i>genesis</i>, origin), the science which deals with heredity
+and the origin of individuals in general.</p>
+
+<p class="hang"><span class="smcap">Genotype</span> (Gr. <i>genea</i>, race; <i>typto</i>, strike), the germinal constitution
+of an organism.</p>
+
+<p class="hang"><span class="smcap">Geotropism</span> (Gr. <i>ge</i>, earth; <i>trop&#275;</i>, turning), defined, <a href="#Page_198">p. 198</a>.</p>
+
+<p class="hang"><span class="smcap">Germ-Cell</span>, a reproductive cell.</p>
+
+<p class="hang"><span class="smcap">Germinal Variations</span>, variations which owe their origin to some
+modification in the germ-cells.</p>
+
+<p class="hang"><span class="smcap">Germ-Plasm</span>, the material basis of inheritance.</p>
+
+<p class="hang"><span class="smcap">Gonad</span> (Gr. <i>gonos</i>, generation), a germ-gland.</p>
+
+<p><span class="pagenum"><a name="Page_347" id="Page_347">[Pg 347]</a></span></p>
+
+<p class="hang"><span class="smcap">Haploid</span> (Gr. <i>haploos</i>, single; <i>eidos</i>, form), the single or reduced
+number of chromosomes as found, for instance, in the mature germ-cells.</p>
+
+<p class="hang"><span class="smcap">Heliotropism</span> (Gr. <i>helios</i>, sun; <i>trop&#275;</i>, turning), defined, <a href="#Page_198">p. 198</a>.</p>
+
+<p class="hang"><span class="smcap">Heredity</span> (L. <i>heres</i>, heir), resemblance of individuals to their
+progenitors based on community of origin.</p>
+
+<p class="hang"><span class="smcap">Heritage</span> (L. <i>heres</i>, heir), all that is inherited by an individual.</p>
+
+<p class="hang"><span class="smcap">Heterozygote</span> (Gr. <i>heteros</i>, other; <i>zygon</i>, yolk), an individual produced
+through the union of germ-cells which are unlike in one or more
+determiners. Adjective, <i>heterozygous</i>.</p>
+
+<p class="hang"><span class="smcap">Homozygote</span> (Gr. <i>homos</i>, same; <i>zygon</i>, yolk), an individual produced
+through the union of germ-cells which are alike in determiners. Adjective,
+<i>homozygous</i>.</p>
+
+<p class="hang"><span class="smcap">Hybrid</span> (L. <i>hybrida</i>, mongrel), the offspring of parents which differ in
+one or more characters.</p>
+
+<p class="hang"><span class="smcap">Identical Twins</span>, twins which show identical inborn characters, both having
+come presumably from the same ovum.</p>
+
+<p class="hang"><span class="smcap">Idiot</span> (Gr. <i>idios</i>, peculiar, private), defined, <a href="#Page_244">p. 244</a>.</p>
+
+<p class="hang"><span class="smcap">Imbecile</span> (L. <i>imbecillis</i>, weak), defined, <a href="#Page_244">p. 244</a>.</p>
+
+<p class="hang"><span class="smcap">Inheritance</span> (L. <i>in</i>, in; <i>heres</i>, heir), the sum of all characters which
+are transmitted by the germ-cells from generation to generation.</p>
+
+<p class="hang"><span class="smcap">Inhibitor</span> (L. <i>in</i>, in; <i>habeo</i>, hold, have), that which checks or
+restrains.</p>
+
+<p class="hang"><span class="smcap">Instinct</span> (L. <i>in</i>, in; <i>stingno</i>, prick), defined, <a href="#Page_203">p. 203</a>.</p>
+
+<p class="hang"><span class="smcap">Intra-uterine</span> (L. <i>intra</i>, within; <i>uterus</i>, the womb), within the womb.</p>
+
+<p class="hang"><span class="smcap">Irritability</span> (L. <i>irrito</i>, excite), the property of responding to stimuli.</p>
+
+<p class="hang"><span class="smcap">Linin</span> (L. <i>linum</i>, flax), filaments of the cell-nucleus not readily
+stained by dyes.</p>
+
+<p><span class="pagenum"><a name="Page_348" id="Page_348">[Pg 348]</a></span></p>
+
+<p class="hang"><span class="smcap">Luetin Test</span> (L. <i>lues</i>, pest), a test for syphilis; see <a href="#Page_188">p. 188</a>.</p>
+
+<p class="hang"><span class="smcap">Mammals</span> (L. <i>mamma</i>, breast), warm-blooded, hairy animals which suckle
+their young.</p>
+
+<p class="hang"><span class="smcap">Maturation</span> (L. <i>maturus</i>, ripe), the final stages in the development of
+the sex-cells characterized by two divisions in one of which the number of
+chromosomes is reduced by one-half.</p>
+
+<p class="hang"><span class="smcap">Mendelian</span>, <span class="smcap">Mendelism</span>, referring to Mendel, the founder of a theory of
+heredity. See <a href="#Page_67">p. 67</a>.</p>
+
+<p class="hang"><span class="smcap">Metazoa</span> (Gr. <i>meta</i>, over; <i>zoon</i>, animal), all animals higher than the
+protozoa.</p>
+
+<p class="hang"><span class="smcap">Mitosis</span> (Gr. <i>mitos</i>, thread), indirect nuclear division, characterized by
+the appearance of a fibrous spindle and a definite number of chromosomes.
+The latter split to form daughter chromosomes which diverge to the poles
+of the spindle to form parts of the new nuclei.</p>
+
+<p class="hang"><span class="smcap">Mongolian</span>, a type of feeble-minded individual, see <a href="#Page_248">p. 248</a>.</p>
+
+<p class="hang"><span class="smcap">Monohybrid</span> (Gr. <i>monos</i>, single; L. <i>hybrida</i>, mongrel), the offspring of
+parents, differing in one character.</p>
+
+<p class="hang"><span class="smcap">Moron</span> (Gr. <i>moros</i>, foolish), defined, <a href="#Page_244">p. 244</a>.</p>
+
+<p class="hang"><span class="smcap">Mutations</span> (L. <i>mutare</i>, to change), abrupt, inheritable germinal
+variations. Frequently though not necessarily they are changes of
+considerable extent.</p>
+
+<p class="hang"><span class="smcap">Neural</span> (Gr. <i>neuron</i>, nerve), pertaining to the nervous system.</p>
+
+<p class="hang"><span class="smcap">Neuron</span> (Gr. <i>neuron</i>, nerve), a nerve-unit consisting of a nerve-cell with
+branching processes called dendrites and an axon or axis cylinder process
+which gives rise to a nerve fiber.</p>
+
+<p class="hang"><span class="smcap">Neuropathic</span> (Gr. <i>neuron</i>, nerve; <i>pathos</i>, suffering), relating to
+disease of the nervous system.</p>
+
+<p><span class="pagenum"><a name="Page_349" id="Page_349">[Pg 349]</a></span></p>
+
+<p class="hang"><span class="smcap">Nucleolus</span> (L. dim. of nucleus), a well-defined body found within the
+nucleus of a cell.</p>
+
+<p class="hang"><span class="smcap">Nucleus</span> (L. <i>nux</i>, a nut), the central organ of a cell.</p>
+
+<p class="hang"><span class="smcap">Nulliplex</span> (L. <i>nullus</i>, not any; <i>plico</i>, fold), the condition in which no
+determiners of a given character exist in a particular individual.</p>
+
+<p class="hang"><span class="smcap">O&ouml;cyte</span> (Gr. <i>&#333;on</i>, egg; <i>kytos</i>, cell), the ovarian egg in one stage of
+development.</p>
+
+<p class="hang"><span class="smcap">O&ouml;genesis</span> (Gr. <i>&#333;on</i>, egg; <i>genesis</i>, origin), the development of ova
+from primitive sex-cells.</p>
+
+<p class="hang"><span class="smcap">O&ouml;gonium</span> (Gr. <i>&#333;on</i>, egg; <i>gonos</i>, generation), a primordial egg-cell.</p>
+
+<p class="hang"><span class="smcap">Ovary</span> (L. <i>ovum</i>, egg), the organ in which the egg-cells multiply and are
+nourished.</p>
+
+<p class="hang"><span class="smcap">Ovum</span> (L. <i>ovum</i>, an egg), the female sex cell.</p>
+
+<p class="hang"><span class="smcap">Parthenogenesis</span> (Gr. <i>parthenos</i>, virgin; <i>genesis</i>, origin), development
+of an egg which has not united with a male gamete.</p>
+
+<p class="hang"><span class="smcap">Phenotype</span> (Gr. <i>phaino</i>, show; <i>typto</i>, strike), the existing type of
+individual irrespective of hereditary possibilities which may reside in it
+undeveloped.</p>
+
+<p class="hang"><span class="smcap">Phototropism</span> (Gr. <i>phos</i>, light; <i>trop&#275;</i>, turning), defined, <a href="#Page_198">p. 198</a>.</p>
+
+<p class="hang"><span class="smcap">Placenta</span> (L. <i>placenta</i>, a flat cake), the organ by which the fetus of the
+higher mammals is attached to the uterine wall of the mother for purposes
+of nourishment, respiration and excretion. In it the maternal and fetal
+blood, although not intermingling, are brought into such close proximity
+that an interchange of dissolved substances is possible.</p>
+
+<p class="hang"><span class="smcap">Polar Bodies</span>, the minute cells which are separated from the egg in its
+maturation divisions.</p>
+
+<p class="hang"><span class="smcap">Primate</span> (L. <i>primus</i>, first), the highest order of animals, including
+monkeys, apes and man.</p>
+
+<p class="hang"><span class="smcap">Pronucleus</span>, the nucleus of the mature ovum or sperm-cell.</p>
+
+<p><span class="pagenum"><a name="Page_350" id="Page_350">[Pg 350]</a></span></p>
+
+<p class="hang"><span class="smcap">Protoplasm</span> (Gr. <i>protos</i>, first; <i>plasma</i>, form), the essential living
+substance.</p>
+
+<p class="hang"><span class="smcap">Protozoa</span> (Gr. <i>protos</i>, first; <i>zoon</i>, animal), single-celled animals or
+animals composed of cells not separable into different tissues.</p>
+
+<p class="hang"><span class="smcap">Psychical</span> (Gr. <i>psyche</i>, the soul), pertaining to the mind.</p>
+
+<p class="hang"><span class="smcap">Recessive Character</span> (L. <i>recessus</i>, a going back), a character from one
+parent which remains undeveloped in offspring when associated with the
+corresponding dominant character from the other parent.</p>
+
+<p class="hang"><span class="smcap">Reduction Division</span>, a division of the maturing germ-cells in which the
+dual or somatic (diploid) number of chromosomes is reduced to the single
+(haploid) number.</p>
+
+<p class="hang"><span class="smcap">Reflex Action</span> (L. <i>re</i>, back; <i>flectere</i>, bend), an automatic response of
+the nervous and motor mechanism of the body.</p>
+
+<p class="hang"><span class="smcap">Restrictive</span> (or negative) <span class="smcap">Eugenics</span>, a system of improving the human race
+by preventing reproduction of the unfit.</p>
+
+<p class="hang"><span class="smcap">Reversion</span> (L. <i>re</i>, back; <i>verto</i>, turn), the reappearance of ancestral
+traits which have for some generations been in abeyance.</p>
+
+<p class="hang"><span class="smcap">Rheotropism</span> (Gr. <i>rheo</i>, to flow; <i>trop&#275;</i>, turning), defined, <a href="#Page_198">p. 198</a>.</p>
+
+<p class="hang"><span class="smcap">Salpingectomy</span> (Gr. <i>salpinx</i>, trumpet; <i>ectom&#275;</i>, cutting out), removal
+of part or all of a Fallopian tube (oviduct).</p>
+
+<p class="hang"><span class="smcap">Segregation</span> (L. <i>se</i>, aside; <i>grex</i>, flock), separation.</p>
+
+<p class="hang"><span class="smcap">Sex Chromosome</span>, a special chromosome which is supposed to be concerned in
+the determination of sex.</p>
+
+<p class="hang"><span class="smcap">Sex-Linked Characters</span>, defined, <a href="#Page_60">p. 60</a>.</p>
+
+<p class="hang"><span class="smcap">Simian</span> (L. <i>simia</i>, ape), ape-like.</p>
+
+<p><span class="pagenum"><a name="Page_351" id="Page_351">[Pg 351]</a></span></p>
+
+<p class="hang"><span class="smcap">Simplex</span> (L. <i>sim</i>, same; <i>plico</i>, fold), the condition in which a
+character is represented by a determiner from only one of the two parents.</p>
+
+<p class="hang"><span class="smcap">Soma</span> (Gr. <i>soma</i>, body), the body considered apart from the germ-cells.</p>
+
+<p class="hang"><span class="smcap">Spermatid</span> (Gr. <i>sperma</i>, seed), a cell resulting from the last division of
+the germ-cell in spermatogenesis. It transforms into the spermatozoon.</p>
+
+<p class="hang"><span class="smcap">Spermatocytes</span> (Gr. <i>sperma</i>, seed; <i>kytos</i>, cell), cells concerned in the
+maturation divisions of the male germ-cells.</p>
+
+<p class="hang"><span class="smcap">Spermatogenesis</span> (Gr. <i>sperma</i>, seed; <i>genesis</i>, origin), the development
+of spermatozoa from primitive sex-cells.</p>
+
+<p class="hang"><span class="smcap">Spermatogonium</span> (Gr. <i>sperma</i>, seed; <i>gonos</i>, generation), a primordial
+sperm-cell.</p>
+
+<p class="hang"><span class="smcap">Spermatozoon</span> (Gr. <i>sperma</i>, seed; <i>zoon</i>, animal), the functional male
+sex-cell.</p>
+
+<p class="hang"><span class="smcap">Spindle</span>, a fibrous organ formed in indirect cell-division.</p>
+
+<p class="hang"><span class="smcap">Spireme</span> (L. <i>spira</i>, coil), a characteristic stage preliminary to indirect
+cell-division in which the chromatin material of the nucleus appears in
+the form of a skein of filaments.</p>
+
+<p class="hang"><span class="smcap">Stereotropism</span> (Gr. <i>stereos</i>, solid; <i>trop&#275;</i>, turning), defined, <a href="#Page_198">p. 198</a>.</p>
+
+<p class="hang"><span class="smcap">Sterilization</span> (L. <i>sterilis</i>, barren), deprivation of reproductive power.
+For methods, see <a href="#Page_322">p. 322</a>.</p>
+
+<p class="hang"><span class="smcap">Synapse</span> (Gr. <i>syn</i>, together; <i>hapto</i>, unite), the coming in contact of
+the processes of one nerve cell with the processes or body of another.</p>
+
+<p class="hang"><span class="smcap">Synapsis</span> (Gr. <i>syn</i>, together; <i>hapto</i>, unite), union of the chromosomes
+in pairs preliminary to the reduction division.</p>
+
+<p class="hang"><span class="smcap">Telegony</span> (Gr. <i>telegonos</i>, born far away), the supposed influence of an
+earlier sire on offspring born later of the same mother to a different sire.</p>
+
+<p><span class="pagenum"><a name="Page_352" id="Page_352">[Pg 352]</a></span></p>
+
+<p class="hang"><span class="smcap">Thermotropism</span> (Gr. <i>thero</i>, heat; <i>trop&#275;</i>, turning), defined, <a href="#Page_198">p. 198</a>.</p>
+
+<p class="hang"><span class="smcap">Thigmotropism</span> (Gr. <i>thigmo</i>, touch; <i>trop&#275;</i>, turning), defined, <a href="#Page_198">p. 198</a>.</p>
+
+<p class="hang"><span class="smcap">Toxin</span> (Gr. <i>toxicon</i>, poison), poisonous compounds of animal, vegetable,
+or bacterial origin.</p>
+
+<p class="hang"><span class="smcap">Tropism</span> (Gr. <i>trop&#275;</i>, turning), the automatic directing of an organism
+toward or away from a source of stimulus.</p>
+
+<p class="hang"><span class="smcap">Unit-Character</span>, a character which behaves as an indivisible unit in
+heredity.</p>
+
+<p class="hang"><span class="smcap">Vasectomy</span> (L. <i>vas</i>, vessel; <i>ektom&#275;</i>, cutting out), removal of a
+portion of the vas deferens (duct for conveying spermatozoa).</p>
+
+<p class="hang"><span class="smcap">Vestigeal</span> (L. <i>vestigium</i>, footstep), representing organs which existed
+once in a more developed condition.</p>
+
+<p class="hang"><span class="smcap">Volvox</span> (L. <i>volvo</i>, roll), a small fresh-water organism occurring in
+spherical colonies.</p>
+
+<p class="hang"><span class="smcap">Wasserman Reaction</span>, a test for syphilis, see <a href="#Page_188">p. 188</a>.</p>
+
+<p class="hang"><span class="smcap">X-Element</span>, same as sex-chromosome.</p>
+
+<p class="hang"><span class="smcap">Zygote</span> (Gr. <i>zygon</i>, yolk), the product of the union of two gametes.</p>
+
+<p><span class="pagenum"><a name="Page_353" id="Page_353">[Pg 353]</a></span></p>
+
+
+
+<p>&nbsp;</p><p>&nbsp;</p>
+<hr style="width: 50%;" />
+<p><span class="pagenum"><a name="Page_354" id="Page_354">[Pg 354]</a></span></p>
+<h2>REFERENCES FOR FURTHER READING AND STUDY</h2>
+
+
+<p>&nbsp;</p>
+<p><span class="pagenum"><a name="Page_355" id="Page_355">[Pg 355]</a></span></p>
+<p class="title">REFERENCES FOR FURTHER READING AND STUDY</p>
+
+
+<p class="hang"><span class="smcap">Bateson, W.</span>, 1909. <i>Mendel&#8217;s Principles of Heredity.</i> Cambridge, The
+University Press. The best technical account of Mendelism. It contains
+also a translation of the original papers of Mendel.</p>
+
+<p class="hang"><span class="smcap">Castle, William E.</span>, 1911. <i>Heredity.</i> New York, D. Appleton and Company.</p>
+
+<p class="hang"><span class="smcap">Castle, William E.</span>; <span class="smcap">Coulter, John M.</span>; <span class="smcap">Davenport, Charles B.</span>; <span class="smcap">East, Edward
+M.</span>; <span class="smcap">Tower, William L.</span>, 1912. <i>Heredity and Eugenics.</i> Chicago, The
+University of Chicago Press.</p>
+
+<p class="hang"><span class="smcap">Conklin, Edwin Grant</span>, 1915. <i>Heredity and Environment in the Development
+of Men.</i> Princeton, Princeton University Press.</p>
+
+<p class="hang"><span class="smcap">Davenport, Charles B.</span>, 1911. <i>Heredity in Relation to Eugenics.</i> New York,
+Henry Holt and Company.</p>
+
+<p class="hang"><span class="smcap">Doncaster, L.</span>, 1911. <i>Heredity in the Light of Recent Research.</i>
+Cambridge, The University Press.</p>
+
+<p class="hang"><span class="smcap">Doncaster, L.</span>, 1915. <i>The Determination of Sex.</i> Cambridge, The University
+Press.</p>
+
+<p class="hang"><span class="smcap">Ellis, Havelock</span>, 1912. <i>The Task of Social Hygiene.</i> New York, Houghton
+Mifflin Company.</p>
+
+<p class="hang"><span class="smcap">Galton, Francis</span>, 1869. <i>Hereditary Genius: an Inquiry Into Its Laws and
+Consequences.</i> London, Macmillan and Company.</p>
+
+<p class="hang"><span class="smcap">Galton, Francis</span>, 1889. <i>Natural Inheritance.</i> New York, The Macmillan
+Company.</p>
+
+<p><span class="pagenum"><a name="Page_356" id="Page_356">[Pg 356]</a></span></p>
+
+<p class="hang"><span class="smcap">Galton, Francis</span>, 1895. <i>English Men of Science; Their Nature and Nurture.</i>
+New York, D. Appleton and Company.</p>
+
+<p class="hang"><span class="smcap">Galton, Francis</span>, and <span class="smcap">Schuster, Edgar</span>, 1906. <i>Noteworthy Families</i> (Modern
+Science). London, J. Murray.</p>
+
+<p class="hang"><span class="smcap">Goddard, Henry Herbert</span>, 1912. <i>The Kallikak Family; a Study in the
+Heredity of Feeble-mindedness.</i> New York, The Macmillan Company.</p>
+
+<p class="hang"><span class="smcap">Goddard, Henry Herbert</span>, 1914. <i>Feeble-mindedness; Its Causes and
+Consequences.</i> New York, The Macmillan Company.</p>
+
+<p class="hang"><span class="smcap">Healy, William</span>, 1915. <i>The Individual Delinquent.</i> Boston, Little, Brown
+and Company.</p>
+
+<p class="hang"><span class="smcap">Kellicott, William E.</span>, 1911. <i>The Social Direction of Human Evolution; an
+Outline of the Science of Eugenics.</i> New York, D. Appleton and Company.</p>
+
+<p class="hang"><span class="smcap">Morgan, Thomas Hunt</span>, 1913. <i>Heredity and Sex.</i> New York, Columbia
+University Press.</p>
+
+<p class="hang"><span class="smcap">Punnett, R. C.</span>, 1911. <i>Mendelism.</i> New York, The Macmillan Company. The
+best popular account of Mendelism.</p>
+
+<p class="hang"><span class="smcap">Saleeby, Caleb William</span>, 1909. <i>Parenthood and Race Culture; an Outline of
+Eugenics.</i> London, Cassell and Company.</p>
+
+<p class="hang"><span class="smcap">Schuster, Edgar</span>, 1912. <i>Eugenics.</i> London, Collins Clear-Type Press.</p>
+
+<p class="hang"><span class="smcap">Thomson, J. Arthur</span>, 1908. <i>Heredity.</i> London, John Murray.</p>
+
+<p class="hang"><span class="smcap">Walter, Herbert Eugene</span>, 1913. <i>Genetics.</i> New York, The Macmillan Company.</p>
+
+<p class="hang"><span class="smcap">Whetham, W. C. D.</span> and C. D., 1909. <i>The Family and the Nation.</i> London,
+Longmans, Green and Company.</p>
+
+<p class="hang"><span class="smcap">Woods, Frederick Adams</span>, 1906. <i>Mental and Moral Heredity in Royalty.</i> New
+York, Henry Holt and Company.</p>
+
+<p><span class="pagenum"><a name="Page_357" id="Page_357">[Pg 357]</a></span></p>
+
+<p class="hang"><span class="smcap">Various Authors</span>, 1914. <i>Eugenics; Twelve University Lectures.</i> New York,
+Dodd, Mead and Company.</p>
+
+<p><span class="smcap">Journals</span>:</p>
+
+<div class="blockquot"><p class="hang"><i>The Journal of Heredity.</i> The organ of the American Genetic
+Association, Washington, D. C.</p>
+
+<p class="hang"><i>The Eugenics Review.</i> Issued at the University of London.</p>
+
+<p class="hang"><i>Memoirs and Bulletins</i> published by the Eugenics Record Office, Cold
+Spring Harbor, Long Island, N. Y.</p></div>
+
+<p>Every one interested in eugenics should be acquainted with the work of
+this office. In its own words its functions are:</p>
+
+<div class="blockquot"><p>1. To serve eugenical interests in the capacity of repository and
+clearing house.</p>
+
+<p>2. To build up an analytical index of the traits of American families.</p>
+
+<p>3. To train field workers to gather data of eugenical import.</p>
+
+<p>4. To maintain a field force actually engaged in gathering such data.</p>
+
+<p>5. To cooperate with other institutions and with persons concerned
+with eugenical study.</p>
+
+<p>6. To investigate the manner of inheritance of specific human traits.</p>
+
+<p>7. To advise concerning the eugenical fitness of proposed marriages.</p>
+
+<p>8. To publish results of researches.</p>
+
+<p>To such persons as will undertake to fill them out it furnishes free
+in duplicate (one copy to be retained by the applicant) the following
+blank schedules: 1. <i>Record of Family Traits.</i> 2. <i>Index to
+Germ-plasm&mdash;A Parallel Family Record for Prospective Marriage Mates.</i>
+3. <i>Musical Talent.</i> 4. <i>Mathematical Talent.</i> 5. <i>Tuberculosis.</i> 6.
+<i>Special Trait Chart.</i> 7. <i>Harelip and Cleft-palate.</i></p>
+
+<p class="hang"><i>Publications of the Volta Bureau</i> of Washington, D. C., an institution
+given over entirely to data regarding deaf mutes.</p>
+
+<p class="hang"><i>Studies in National Deterioration.</i> The University of London.</p>
+
+<p class="hang"><span class="pagenum"><a name="Page_358" id="Page_358">[Pg 358]</a></span></p>
+
+<p class="hang"><i>Memoirs and Lectures</i>, from the Biometric Laboratory, University of
+London.</p>
+
+<p class="hang"><i>Treasury of Human Inheritance</i>, a series of studies being issued from the
+Eugenics Laboratory, University College, London.</p></div>
+
+<p><span class="pagenum"><a name="Page_359" id="Page_359">[Pg 359]</a></span></p>
+
+
+
+<p>&nbsp;</p><p>&nbsp;</p>
+<hr style="width: 50%;" /><p><span class="pagenum"><a name="Page_360" id="Page_360">[Pg 360]</a></span></p>
+<h2>INDEX</h2>
+
+<p>&nbsp;</p>
+<p><span class="pagenum"><a name="Page_361" id="Page_361">[Pg 361]</a></span></p>
+<p class="title">INDEX</p>
+
+
+<p class="index">
+Ability: <a href="#Page_118">118</a>;<br />
+<span style="margin-left: 1em;">calculating, literary, musical, <a href="#Page_120">120</a>.</span><br />
+<br />
+Able child likely to be neglected, <a href="#Page_257">257</a>.<br />
+<br />
+Achondroplasy, <a href="#Page_113">113</a>.<br />
+<br />
+Acquired characters, inheritance of, <a href="#Page_121">121</a>.<br />
+<br />
+Adami, <a href="#Page_164">164</a>.<br />
+<br />
+Adaptations, establishment of, <a href="#Page_140">140</a>.<br />
+<br />
+Adaptive responses, <a href="#Page_201">201</a>.<br />
+<br />
+Agassiz, <a href="#Page_297">297</a>.<br />
+<br />
+Albinism, in man, <a href="#Page_116">116</a>.<br />
+<br />
+Alcohol: and crime, <a href="#Page_279">279</a>;<br />
+<span style="margin-left: 1em;">and degeneracy, <a href="#Page_172">172</a>, <a href="#Page_179">179</a>;</span><br />
+<span style="margin-left: 1em;">and germinal tissue, <a href="#Page_172">172</a>;</span><br />
+<span style="margin-left: 1em;">a poison, <a href="#Page_168">168</a>.</span><br />
+<br />
+Alcoholism: <a href="#Page_101">101</a>, <a href="#Page_117">117</a>, <a href="#Page_167">167</a>;<br />
+<span style="margin-left: 1em;">factors in, <a href="#Page_180">180</a>;</span><br />
+<span style="margin-left: 1em;">in lower animals, <a href="#Page_173">173-178</a>;</span><br />
+<span style="margin-left: 1em;">views regarding inheritance of, <a href="#Page_169">169</a>, <a href="#Page_170">170</a>, <a href="#Page_172">172</a>, <a href="#Page_178">178</a>, <a href="#Page_179">179</a>, <a href="#Page_180">180</a>.</span><br />
+<br />
+Alkaptonuria, <a href="#Page_117">117</a>.<br />
+<br />
+Allelomorph, <a href="#Page_77">77</a>.<br />
+<br />
+Alpine plants, non-inheritance of acquired characters, <a href="#Page_131">131</a>.<br />
+<br />
+Alternative action in behavior, <a href="#Page_207">207</a>.<br />
+<br />
+Altruism, possible origin of, <a href="#Page_220">220</a>.<br />
+<br />
+Ambystoma, <a href="#Page_132">132</a>.<br />
+<br />
+Ameba, <a href="#Page_23">23</a>, <a href="#Page_24">24</a>.<br />
+<br />
+Ancestors, number of, <a href="#Page_4">4</a>.<br />
+<br />
+Ancestry: a network, <a href="#Page_3">3</a>;<br />
+<span style="margin-left: 1em;">dual, <a href="#Page_6">6</a>;</span><br />
+<span style="margin-left: 1em;">in royalty, <a href="#Page_5">5</a>;</span><br />
+<span style="margin-left: 1em;">pride of, as a eugenic agent, <a href="#Page_309">309</a>.</span><br />
+<br />
+<br />
+Backward child, <a href="#Page_256">256</a>.<br />
+<br />
+Backwardness, importance of early determination, <a href="#Page_256">256</a>, <a href="#Page_257">257</a>.<br />
+<br />
+Bardeen, <a href="#Page_126">126</a>.<br />
+<br />
+Barker, <a href="#Page_229">229</a>.<br />
+<br />
+Barr, <a href="#Page_246">246</a>, <a href="#Page_247">247</a>, <a href="#Page_248">248</a>.<br />
+<br />
+Barrington, <a href="#Page_179">179</a>.<br />
+<br />
+Bateson, <a href="#Page_77">77</a>, <a href="#Page_82">82</a>.<br />
+<br />
+Bees, inheritance in, <a href="#Page_136">136</a>, <a href="#Page_137">137</a>.<br />
+<br />
+Behavior: lower animals, <a href="#Page_197">197</a>;<br />
+<span style="margin-left: 1em;">modifiability of, <a href="#Page_200">200</a>, <a href="#Page_204">204-207</a>, <a href="#Page_217">217</a>, <a href="#Page_219">219</a>, <a href="#Page_224">224</a>, <a href="#Page_225">225</a>, <a href="#Page_337">337</a>;</span><br />
+<span style="margin-left: 1em;">not wholly established by heredity, <a href="#Page_217">217</a>, <a href="#Page_227">227</a>;</span><br />
+<span style="margin-left: 1em;">rational, <a href="#Page_205">205</a>, <a href="#Page_206">206</a>;</span><br />
+<span style="margin-left: 1em;">various forms of, possible, <a href="#Page_207">207</a>, <a href="#Page_219">219</a>.</span><br />
+<br />
+Bell, <a href="#Page_152">152</a>.<br />
+<br />
+Bezzola, <a href="#Page_170">170</a>.<br />
+<span class="pagenum"><a name="Page_362" id="Page_362">[Pg 362]</a></span><br />
+Billings, <a href="#Page_249">249</a>.<br />
+<br />
+Binet-Simon test, <a href="#Page_255">255</a>.<br />
+<br />
+Biometry, <a href="#Page_16">16</a>.<br />
+<br />
+Birthmarks, <a href="#Page_159">159</a>, <a href="#Page_160">160</a>.<br />
+<br />
+Birth-rate: significance of, <a href="#Page_302">302</a>;<br />
+<span style="margin-left: 1em;">too low in desirable stocks, <a href="#Page_302">302</a>, <a href="#Page_304">304</a>, <a href="#Page_305">305</a>, <a href="#Page_307">307</a>.</span><br />
+<br />
+Blastomeres, <a href="#Page_55">55</a>.<br />
+<br />
+Blastophthoria, <a href="#Page_163">163</a>.<br />
+<br />
+Blended inheritance, <a href="#Page_87">87</a>, <a href="#Page_92">92</a>, <a href="#Page_93">93</a>.<br />
+<br />
+Blends, mistakes for, <a href="#Page_91">91</a>.<br />
+<br />
+Blindness, infantile, <a href="#Page_183">183</a>.<br />
+<br />
+Blistering, <a href="#Page_113">113</a>.<br />
+<br />
+Body: how built up from germ, <a href="#Page_36">36</a>;<br />
+<span style="margin-left: 1em;">duality of, <a href="#Page_50">50</a>.</span><br />
+<br />
+Brachydactylism, <a href="#Page_107">107</a>.<br />
+<br />
+Brain: in higher animals, <a href="#Page_213">213</a>;<br />
+<span style="margin-left: 1em;">mechanism, maladjustments of, <a href="#Page_230">230</a>.</span><br />
+<br />
+Branthwaite, <a href="#Page_180">180</a>, <a href="#Page_292">292</a>.<br />
+<br />
+Breeding, experiments, method of, <a href="#Page_14">14</a>, <a href="#Page_15">15</a>.<br />
+<br />
+Brewer, <a href="#Page_142">142</a>.<br />
+<br />
+Brieux, <a href="#Page_101">101</a>.<br />
+<br />
+Bronner, <a href="#Page_266">266</a>.<br />
+<br />
+Brown Sequard, <a href="#Page_132">132</a>, <a href="#Page_133">133</a>.<br />
+<br />
+<br />
+Cabot, <a href="#Page_183">183</a>.<br />
+<br />
+Cacogenic strains, <a href="#Page_310">310</a>.<br />
+<br />
+Cajal, <a href="#Page_209">209</a>.<br />
+<br />
+Cancer, <a href="#Page_117">117</a>, <a href="#Page_154">154</a>.<br />
+<br />
+Capsella, <a href="#Page_131">131</a>.<br />
+<br />
+Castle, <a href="#Page_134">134</a>.<br />
+<br />
+Cataract, presenile, <a href="#Page_112">112</a>.<br />
+<br />
+Cattle: horn characters, <a href="#Page_79">79</a>;<br />
+<span style="margin-left: 1em;">roan, <a href="#Page_81">81</a>.</span><br />
+<br />
+Cell: a unit of structure, <a href="#Page_20">20</a>;<br />
+<span style="margin-left: 1em;">diagram of, <a href="#Page_21">21</a>;</span><br />
+<span style="margin-left: 1em;">structure of, <a href="#Page_20">20</a>, <a href="#Page_30">30</a>.</span><br />
+<br />
+Cell-division: <a href="#Page_31">31</a>;<br />
+<span style="margin-left: 1em;">indirect (mitosis), <a href="#Page_32">32</a>;</span><br />
+<span style="margin-left: 1em;">meaning of indirect, <a href="#Page_34">34</a>.</span><br />
+<br />
+Cell-theory, <a href="#Page_22">22</a>.<br />
+<br />
+Cellular basis of heredity, <a href="#Page_22">22</a>.<br />
+<br />
+Ceni, <a href="#Page_174">174</a>.<br />
+<br />
+Centrosome, <a href="#Page_31">31</a>.<br />
+<br />
+Cerebral cortex, not functionally homogeneous, <a href="#Page_211">211</a>.<br />
+<br />
+Character: defined, <a href="#Page_12">12</a>;<br />
+<span style="margin-left: 1em;">dominant, <a href="#Page_74">74</a>;</span><br />
+<span style="margin-left: 1em;">recessive, <a href="#Page_74">74</a>.</span><br />
+<br />
+Characters: contrasted, <a href="#Page_69">69</a>;<br />
+<span style="margin-left: 1em;">determiners of, <a href="#Page_13">13</a>, <a href="#Page_14">14</a>;</span><br />
+<span style="margin-left: 1em;">independence of, <a href="#Page_69">69</a>;</span><br />
+<span style="margin-left: 1em;">inheritable and non-inheritable, <a href="#Page_121">121</a>, <a href="#Page_122">122</a>;</span><br />
+<span style="margin-left: 1em;">more than two pairs of, <a href="#Page_87">87</a>;</span><br />
+<span style="margin-left: 1em;">new combinations of, <a href="#Page_82">82</a>, <a href="#Page_83">83</a>, <a href="#Page_84">84</a>;</span><br />
+<span style="margin-left: 1em;">separable, <a href="#Page_69">69</a>;</span><br />
+<span style="margin-left: 1em;">symbols for, <a href="#Page_78">78</a>;</span><br />
+<span style="margin-left: 1em;">two pairs of, <a href="#Page_82">82</a>.</span><br />
+<br />
+Chauvin, <a href="#Page_132">132</a>.<br />
+<br />
+Chemotropism, <a href="#Page_198">198</a>.<br />
+<br />
+Childbirths, intervals between, <a href="#Page_165">165</a>.<br />
+<span class="pagenum"><a name="Page_363" id="Page_363">[Pg 363]</a></span><br />
+Children of the future: ours to determine quality of, <a href="#Page_338">338</a>, <a href="#Page_339">339</a>;<br />
+<span style="margin-left: 1em;">and home, <a href="#Page_338">338</a>.</span><br />
+<br />
+Cholera, <a href="#Page_152">152</a>.<br />
+<br />
+Chorea: <a href="#Page_117">117</a>;<br />
+<span style="margin-left: 1em;">Huntington&#8217;s, <a href="#Page_113">113-115</a>, <a href="#Page_243">243</a>, <a href="#Page_325">325</a>.</span><br />
+<br />
+Chromatin, <a href="#Page_31">31</a>.<br />
+<br />
+Chromosome, <a href="#Page_32">32</a>.<br />
+<br />
+Chromosomes: individuality of, <a href="#Page_39">39</a>, <a href="#Page_48">48</a>;<br />
+<span style="margin-left: 1em;">determiners in, <a href="#Page_94">94</a>;</span><br />
+<span style="margin-left: 1em;">in germ and body cells, <a href="#Page_40">40</a>;</span><br />
+<span style="margin-left: 1em;">Mendelian factors and, <a href="#Page_93">93</a>;</span><br />
+<span style="margin-left: 1em;">number and appearance, <a href="#Page_34">34</a>, <a href="#Page_41">41</a>;</span><br />
+<span style="margin-left: 1em;">pairs of, <a href="#Page_40">40</a>, <a href="#Page_93">93</a>, <a href="#Page_94">94</a>;</span><br />
+<span style="margin-left: 1em;">significance of, in heredity, <a href="#Page_35">35</a>, <a href="#Page_49">49</a>, <a href="#Page_50">50</a>, <a href="#Page_51">51</a>, <a href="#Page_53">53</a>, <a href="#Page_54">54</a>.</span><br />
+<br />
+Chromotropism, <a href="#Page_198">198</a>.<br />
+<br />
+Church, <a href="#Page_242">242</a>.<br />
+<br />
+Cleavage, <a href="#Page_36">36</a>.<br />
+<br />
+Cleft-palate, <a href="#Page_178">178</a>.<br />
+<br />
+Cole, <a href="#Page_166">166</a>.<br />
+<br />
+College graduates and birth-rate, <a href="#Page_304">304</a>.<br />
+<br />
+Coloboma, <a href="#Page_113">113</a>.<br />
+<br />
+Color-blindness, <a href="#Page_60">60-62</a>.<br />
+<br />
+Conceptual thought, origin of, <a href="#Page_206">206</a>.<br />
+<br />
+Conduct: importance to young of practise, <a href="#Page_221">221</a>, <a href="#Page_223">223</a>;<br />
+<span style="margin-left: 1em;">hereditary predisposition and, <a href="#Page_218">218</a>, <a href="#Page_337">337</a>;</span><br />
+<span style="margin-left: 1em;">responsibility for, <a href="#Page_195">195</a>.</span><br />
+<br />
+Congenital traits, <a href="#Page_123">123</a>.<br />
+<br />
+Conjugation, <a href="#Page_25">25</a>.<br />
+<br />
+Consciousness, <a href="#Page_206">206</a>.<br />
+<br />
+Conservation: of superior strains, <a href="#Page_157">157</a>;<br />
+<span style="margin-left: 1em;">human, <a href="#Page_299">299</a>, <a href="#Page_300">300</a>.</span><br />
+<br />
+Constructive eugenics, <a href="#Page_309">309</a>.<br />
+<br />
+Corneal opacity, <a href="#Page_113">113</a>.<br />
+<br />
+Correns, <a href="#Page_68">68</a>.<br />
+<br />
+Cortex of brain, <a href="#Page_195">195</a>, <a href="#Page_213">213</a>.<br />
+<br />
+Cost, of caring for our disordered and delinquent, <a href="#Page_257">257</a>, <a href="#Page_300">300</a>.<br />
+<br />
+Cretins, effects of segregating the sexes, <a href="#Page_321">321</a>.<br />
+<br />
+Crime: and delinquency, <a href="#Page_263">263</a>, <a href="#Page_287">287</a>;<br />
+<span style="margin-left: 1em;">and feeble-mindedness, <a href="#Page_264">264-270</a>;</span><br />
+<span style="margin-left: 1em;">bearings of immigration on, <a href="#Page_280">280</a>;</span><br />
+<span style="margin-left: 1em;">classifications of, <a href="#Page_276">276</a>;</span><br />
+<span style="margin-left: 1em;">defined, <a href="#Page_276">276</a>;</span><br />
+<span style="margin-left: 1em;">heredity vs. environment in, <a href="#Page_263">263</a>;</span><br />
+<span style="margin-left: 1em;">increase in, <a href="#Page_272">272</a>;</span><br />
+<span style="margin-left: 1em;">mental disorders most frequently associated with, <a href="#Page_279">279</a>;</span><br />
+<span style="margin-left: 1em;">no specific hereditary factor for, <a href="#Page_275">275</a>.</span><br />
+<br />
+Criminal: the born, <a href="#Page_277">277</a>;<br />
+<span style="margin-left: 1em;">the epileptic, <a href="#Page_277">277</a>.</span><br />
+<br />
+Criminality, <a href="#Page_117">117</a>.<br />
+<br />
+Criss-cross inheritance, <a href="#Page_61">61</a>.<br />
+<br />
+Criteria for judging reproductive fitness, <a href="#Page_304">304</a>, <a href="#Page_306">306</a>.<br />
+<br />
+Cytoplasm: <a href="#Page_30">30</a>;<br />
+<span style="margin-left: 1em;">in heredity, <a href="#Page_51">51</a>.</span><br />
+<br />
+<br />
+Daltonism, <a href="#Page_60">60</a>.<br />
+<br />
+Dana, <a href="#Page_257">257</a>.<br />
+<br />
+Darwin, pedigree of, <a href="#Page_316">316</a>.<br />
+<br />
+Davenport, <a href="#Page_92">92</a>, <a href="#Page_116">116</a>, <a href="#Page_231">231</a>, <a href="#Page_243">243</a>, <a href="#Page_257">257</a>, <a href="#Page_271">271</a>, <a href="#Page_273">273</a>, <a href="#Page_284">284</a>, <a href="#Page_291">291</a>, <a href="#Page_304">304</a>, <a href="#Page_312">312</a>.<br />
+<br />
+Davis, <a href="#Page_185">185</a>.<br />
+<br />
+Deaf-mutism, <a href="#Page_152">152</a>, <a href="#Page_153">153</a>.<br />
+<span class="pagenum"><a name="Page_364" id="Page_364">[Pg 364]</a></span><br />
+Death, natural, <a href="#Page_28">28</a>.<br />
+<br />
+Decline of nations, <a href="#Page_290">290</a>, <a href="#Page_300">300</a>.<br />
+<br />
+Defective delinquent, should prevent procreation of, <a href="#Page_335">335</a>.<br />
+<br />
+Defectives: increase due to breeding, <a href="#Page_290">290</a>, <a href="#Page_291">291</a>;<br />
+<span style="margin-left: 1em;">natural elimination done away with among, <a href="#Page_292">292</a>;</span><br />
+<span style="margin-left: 1em;">unpardonable to let multiply, <a href="#Page_288">288</a>.</span><br />
+<br />
+Defects: breeding out, <a href="#Page_118">118</a>, <a href="#Page_119">119</a>;<br />
+<span style="margin-left: 1em;">mental and nervous, <a href="#Page_228">228</a>.</span><br />
+<br />
+Degenerate strains: <a href="#Page_269">269</a>;<br />
+<span style="margin-left: 1em;">not a product of surroundings, <a href="#Page_273">273</a>.</span><br />
+<br />
+Degenerates, sterilization of married, <a href="#Page_330">330</a>.<br />
+<br />
+Delinquency, causes of, <a href="#Page_267">267</a>, <a href="#Page_274">274</a>.<br />
+<br />
+Delinquents not all defectives, <a href="#Page_274">274</a>.<br />
+<br />
+Delinquent women and girls, many mentally defective, <a href="#Page_265">265</a>, <a href="#Page_266">266</a>.<br />
+<br />
+Dendrite, <a href="#Page_208">208</a>.<br />
+<br />
+De Sanctis, <a href="#Page_256">256</a>.<br />
+<br />
+Determiners: <a href="#Page_13">13</a>, <a href="#Page_77">77</a>;<br />
+<span style="margin-left: 1em;">different producing the same character, <a href="#Page_88">88</a>, <a href="#Page_90">90</a>;</span><br />
+<span style="margin-left: 1em;">segregation of, <a href="#Page_84">84</a>.</span><br />
+<br />
+Development: in higher organisms, <a href="#Page_28">28</a>;<br />
+<span style="margin-left: 1em;">suppressed, <a href="#Page_9">9</a>.</span><br />
+<br />
+De Vries, <a href="#Page_68">68</a>.<br />
+<br />
+Diabetes, <a href="#Page_113">113</a>.<br />
+<br />
+Difficulty, educational value of, <a href="#Page_222">222</a>, <a href="#Page_223">223</a>.<br />
+<br />
+Digital malformations, <a href="#Page_107">107</a>.<br />
+<br />
+Dihybrids, <a href="#Page_82">82</a>.<br />
+<br />
+Diploid number of chromosomes, <a href="#Page_41">41</a>, <a href="#Page_43">43</a>.<br />
+<br />
+Disease: defined, <a href="#Page_146">146</a>;<br />
+<span style="margin-left: 1em;">inheritance of, <a href="#Page_98">98</a>, <a href="#Page_148">148</a>;</span><br />
+<span style="margin-left: 1em;">predisposition to, <a href="#Page_148">148</a>;</span><br />
+<span style="margin-left: 1em;">reappearance of not necessarily inheritance, <a href="#Page_146">146</a>.</span><br />
+<br />
+Dominance: <a href="#Page_74">74</a>;<br />
+<span style="margin-left: 1em;">delayed, <a href="#Page_81">81</a>;</span><br />
+<span style="margin-left: 1em;">incomplete, <a href="#Page_80">80</a>, <a href="#Page_100">100</a>;</span><br />
+<span style="margin-left: 1em;">in human genealogies, <a href="#Page_102">102</a>;</span><br />
+<span style="margin-left: 1em;">in man, <a href="#Page_99">99</a>, <a href="#Page_107">107</a>.</span><br />
+<br />
+Don Carlos, number of ancestors, <a href="#Page_5">5</a>.<br />
+<br />
+Drosophila, <a href="#Page_66">66</a>.<br />
+<br />
+Duplex character, <a href="#Page_80">80</a>, <a href="#Page_99">99</a>.<br />
+<br />
+Dwarfing, by starvation, <a href="#Page_130">130</a>.<br />
+<br />
+Dwarfs, true, <a href="#Page_117">117</a>.<br />
+<br />
+<br />
+East, <a href="#Page_91">91</a>.<br />
+<br />
+Education: actual practise in carrying out projects important, <a href="#Page_221">221</a>;<br />
+<span style="margin-left: 1em;">affording opportunity for development of good traits, <a href="#Page_226">226</a>;</span><br />
+<span style="margin-left: 1em;">effects of not inherited, <a href="#Page_142">142</a>, <a href="#Page_155">155</a>;</span><br />
+<span style="margin-left: 1em;">establishing pathways through the nervous system, <a href="#Page_210">210</a>;</span><br />
+<span style="margin-left: 1em;">importance of difficulty in, <a href="#Page_222">222</a>, <a href="#Page_223">223</a>;</span><br />
+<span style="margin-left: 1em;">non-transference of skill acquired in one line to other lines, <a href="#Page_213">213</a>;</span><br />
+<span style="margin-left: 1em;">providing proper stimuli, <a href="#Page_226">226</a>;</span><br />
+<span style="margin-left: 1em;">training in motive necessary, <a href="#Page_220">220</a>;</span><br />
+<span style="margin-left: 1em;">value of interest in, <a href="#Page_223">223</a>.</span><br />
+<br />
+Egg, a cell, <a href="#Page_22">22</a>.<br />
+<br />
+Egg-cell and sperm-cell contrasted, <a href="#Page_29">29</a>.<br />
+<br />
+Elderton, <a href="#Page_179">179</a>, <a href="#Page_296">296</a>.<br />
+<br />
+Electrotropism, <a href="#Page_198">198</a>.<br />
+<span class="pagenum"><a name="Page_365" id="Page_365">[Pg 365]</a></span><br />
+Ellis, <a href="#Page_265">265</a>, <a href="#Page_301">301</a>.<br />
+<br />
+Embryo, relation to mother, <a href="#Page_161">161</a>.<br />
+<br />
+Embryogeny, <a href="#Page_36">36</a>.<br />
+<br />
+Emerick, <a href="#Page_251">251</a>.<br />
+<br />
+Environment: direct action on germ cells, <a href="#Page_124">124</a>, <a href="#Page_125">125</a>;<br />
+<span style="margin-left: 1em;">effects of faulty, <a href="#Page_158">158</a>;</span><br />
+<span style="margin-left: 1em;">in crime and delinquency, <a href="#Page_263">263</a>, <a href="#Page_266">266</a>, <a href="#Page_273">273</a>, <a href="#Page_274">274</a>.</span><br />
+<br />
+Epidermolysis, <a href="#Page_113">113</a>.<br />
+<br />
+Epilepsy: <a href="#Page_101">101</a>, <a href="#Page_117">117</a>, <a href="#Page_242">242</a>, <a href="#Page_249">249</a>, <a href="#Page_251">251</a>, <a href="#Page_252">252</a>, <a href="#Page_253">253</a>;<br />
+<span style="margin-left: 1em;">in guinea-pigs, <a href="#Page_132">132</a>;</span><br />
+<span style="margin-left: 1em;">relation to feeble-mindedness, <a href="#Page_249">249</a>.</span><br />
+<br />
+Epileptic, the criminal type, <a href="#Page_277">277-279</a>.<br />
+<br />
+Epileptics, number of, <a href="#Page_230">230</a>, <a href="#Page_246">246</a>, <a href="#Page_250">250</a>.<br />
+<br />
+Eugenic agent, educated public sentiment, <a href="#Page_330">330</a>.<br />
+<br />
+Eugenics: and education, <a href="#Page_309">309</a>;<br />
+<span style="margin-left: 1em;">and personal liberty, <a href="#Page_332">332</a>;</span><br />
+<span style="margin-left: 1em;">a working program of, <a href="#Page_335">335</a>;</span><br />
+<span style="margin-left: 1em;">constructive, based on education, <a href="#Page_301">301</a>;</span><br />
+<span style="margin-left: 1em;">defined, <a href="#Page_293">293</a>;</span><br />
+<span style="margin-left: 1em;">desirable traits, <a href="#Page_306">306</a>;</span><br />
+<span style="margin-left: 1em;">education of women in, <a href="#Page_333">333</a>;</span><br />
+<span style="margin-left: 1em;">influence of public opinion on, <a href="#Page_331">331</a>;</span><br />
+<span style="margin-left: 1em;">much yet to be done, <a href="#Page_333">333</a>, <a href="#Page_334">334</a>;</span><br />
+<span style="margin-left: 1em;">positive and negative, <a href="#Page_301">301</a>.</span><br />
+<br />
+Ewart, <a href="#Page_10">10</a>, <a href="#Page_165">165</a>.<br />
+<br />
+Exceptional child likely to be neglected, <a href="#Page_257">257</a>.<br />
+<br />
+Experimental breeding, method of, <a href="#Page_15">15</a>.<br />
+<br />
+External conditions, influences of, <a href="#Page_130">130</a>.<br />
+<br />
+Eye-color: <a href="#Page_9">9</a>, <a href="#Page_103">103</a>;<br />
+<span style="margin-left: 1em;">inheritance of, <a href="#Page_104">104</a>.</span><br />
+<br />
+Eye-defects, <a href="#Page_108">108</a>, <a href="#Page_110">110</a>.<br />
+<br />
+<br />
+Family pride and eugenics, <a href="#Page_309">309</a>.<br />
+<br />
+Farabee, <a href="#Page_106">106</a>.<br />
+<br />
+Fay, <a href="#Page_153">153</a>.<br />
+<br />
+Feeble-minded: prevention of procreation in, <a href="#Page_258">258</a>, <a href="#Page_335">335</a>;<br />
+<span style="margin-left: 1em;">results of non-restraint, <a href="#Page_246">246</a>.</span><br />
+<br />
+Feeble-mindedness: <a href="#Page_101">101</a>, <a href="#Page_117">117</a>;<br />
+<span style="margin-left: 1em;">and crime, <a href="#Page_264">264-269</a>, <a href="#Page_279">279</a>;</span><br />
+<span style="margin-left: 1em;">grades of, <a href="#Page_244">244</a>;</span><br />
+<span style="margin-left: 1em;">inheritance of, <a href="#Page_245">245</a>;</span><br />
+<span style="margin-left: 1em;">not insanity, <a href="#Page_238">238</a>;</span><br />
+<span style="margin-left: 1em;">relation of alcohol to, <a href="#Page_169">169-172</a>.</span><br />
+<br />
+Fernald, <a href="#Page_256">256</a>, <a href="#Page_266">266</a>.<br />
+<br />
+Fertilization, <a href="#Page_26">26</a>, <a href="#Page_29">29</a>, <a href="#Page_47">47</a>, <a href="#Page_48">48</a>.<br />
+<br />
+Fetus: poisoning of, <a href="#Page_162">162</a>;<br />
+<span style="margin-left: 1em;">relation to mother, <a href="#Page_161">161</a>.</span><br />
+<br />
+Fiber-tracts in man, <a href="#Page_214">214</a>.<br />
+<br />
+Fitness, criteria for judging, <a href="#Page_304">304</a>, <a href="#Page_306">306</a>.<br />
+<br />
+Flexner, <a href="#Page_186">186</a>.<br />
+<br />
+Forel, <a href="#Page_169">169</a>, <a href="#Page_173">173</a>, <a href="#Page_303">303</a>.<br />
+<br />
+Fowl, Andalusian, <a href="#Page_69">69</a>, <a href="#Page_70">70</a>, <a href="#Page_71">71</a>.<br />
+<br />
+Frederick the Great, number of ancestors, <a href="#Page_5">5</a>.<br />
+<br />
+Friedreich&#8217;s disease, <a href="#Page_117">117</a>.<br />
+<br />
+Fruit-fly, <a href="#Page_66">66</a>.<br />
+<br />
+<br />
+Galton, <a href="#Page_293">293</a>, <a href="#Page_295">295</a>.<br />
+<br />
+Gamete, <a href="#Page_28">28</a>, <a href="#Page_40">40</a>.<br />
+<span class="pagenum"><a name="Page_366" id="Page_366">[Pg 366]</a></span><br />
+Gametes in dihybrids, <a href="#Page_85">85</a>.<br />
+<br />
+Gametic matings in man, <a href="#Page_100">100</a>.<br />
+<br />
+Geddes, <a href="#Page_55">55</a>.<br />
+<br />
+Genealogies, imperfect, <a href="#Page_98">98</a>.<br />
+<br />
+Genotype, <a href="#Page_86">86</a>.<br />
+<br />
+Geotropism, <a href="#Page_198">198</a>.<br />
+<br />
+Germ and body distinct, <a href="#Page_37">37</a>, <a href="#Page_38">38</a>.<br />
+<br />
+Germ: control of possibilities in, <a href="#Page_224">224</a>;<br />
+<span style="margin-left: 1em;">singleness of, <a href="#Page_50">50</a>.</span><br />
+<br />
+German emperor, number of ancestors, <a href="#Page_5">5</a>.<br />
+<br />
+Germ-cells: affected by poisons, <a href="#Page_126">126</a>;<br />
+<span style="margin-left: 1em;">changes in, <a href="#Page_126">126</a>, <a href="#Page_127">127</a>;</span><br />
+<span style="margin-left: 1em;">early set apart, <a href="#Page_37">37</a>;</span><br />
+<span style="margin-left: 1em;">question of effects of body on, <a href="#Page_128">128</a>, <a href="#Page_135">135</a>;</span><br />
+<span style="margin-left: 1em;">effects of external influences on, <a href="#Page_124">124</a>;</span><br />
+<span style="margin-left: 1em;">in Miastor, <a href="#Page_37">37</a>, <a href="#Page_38">38</a>;</span><br />
+<span style="margin-left: 1em;">metabolic changes in, <a href="#Page_138">138</a>;</span><br />
+<span style="margin-left: 1em;">origin of, <a href="#Page_36">36</a>, <a href="#Page_37">37</a>;</span><br />
+<span style="margin-left: 1em;">possibilities of development, <a href="#Page_127">127</a>;</span><br />
+<span style="margin-left: 1em;">two classes of, <a href="#Page_71">71</a>, <a href="#Page_73">73</a>.</span><br />
+<br />
+Germinal continuity, <a href="#Page_39">39</a>.<br />
+<br />
+Germinal variation and the origin of new characters: <a href="#Page_138">138</a>;<br />
+<span style="margin-left: 1em;">cases analyzed, <a href="#Page_141">141</a>;</span><br />
+<span style="margin-left: 1em;">sexual reproduction in relation to, <a href="#Page_138">138</a>.</span><br />
+<br />
+Germ-plasm and bad environment, <a href="#Page_194">194</a>.<br />
+<br />
+Gifted persons, <a href="#Page_212">212</a>.<br />
+<br />
+Glaucoma, <a href="#Page_113">113</a>.<br />
+<br />
+Goddard, <a href="#Page_118">118</a>, <a href="#Page_171">171</a>, <a href="#Page_174">174</a>, <a href="#Page_188">188</a>, <a href="#Page_235">235</a>, <a href="#Page_238">238</a>, <a href="#Page_245">245</a>, <a href="#Page_250">250</a>, <a href="#Page_256">256</a>, <a href="#Page_257">257</a>, <a href="#Page_264">264</a>, <a href="#Page_269">269</a>, <a href="#Page_326">326</a>.<br />
+<br />
+Gonads, transplantation of, <a href="#Page_134">134</a>.<br />
+<br />
+Gonorrhoea: seriousness of, <a href="#Page_182">182</a>;<br />
+<span style="margin-left: 1em;">prevalence, <a href="#Page_183">183</a>.</span><br />
+<br />
+Gorst, <a href="#Page_234">234</a>.<br />
+<br />
+Gout, <a href="#Page_153">153</a>, <a href="#Page_234">234</a>.<br />
+<br />
+Guinea-pigs: alcoholism in, <a href="#Page_175">175</a>;<br />
+<span style="margin-left: 1em;">Mendelism in, <a href="#Page_75">75</a>.</span><br />
+<br />
+Guyer, <a href="#Page_59">59</a>.<br />
+<br />
+<br />
+Habit, <a href="#Page_219">219</a>.<br />
+<br />
+Habits, modification of in lower animals, <a href="#Page_204">204</a>.<br />
+<br />
+Hair-color, <a href="#Page_105">105</a>.<br />
+<br />
+Hair shape, <a href="#Page_105">105</a>.<br />
+<br />
+Hamburger, <a href="#Page_150">150</a>.<br />
+<br />
+Handwriting, <a href="#Page_120">120</a>.<br />
+<br />
+Haploid number of chromosomes, <a href="#Page_41">41</a>, <a href="#Page_43">43</a>.<br />
+<br />
+Harelip, <a href="#Page_178">178</a>.<br />
+<br />
+Hart, <a href="#Page_266">266</a>, <a href="#Page_319">319</a>, <a href="#Page_326">326</a>.<br />
+<br />
+Healy, <a href="#Page_256">256</a>, <a href="#Page_274">274</a>, <a href="#Page_278">278</a>.<br />
+<br />
+Hearing, hardness of, <a href="#Page_118">118</a>.<br />
+<br />
+Heart disease, <a href="#Page_154">154</a>.<br />
+<br />
+Hegner, <a href="#Page_27">27</a>, <a href="#Page_38">38</a>.<br />
+<br />
+Heliotropism, <a href="#Page_198">198</a>.<br />
+<br />
+Helm, <a href="#Page_109">109</a>, <a href="#Page_111">111</a>.<br />
+<br />
+Hemophilia, <a href="#Page_64">64</a>.<br />
+<br />
+Hereditary character defined, <a href="#Page_12">12</a>.<br />
+<span class="pagenum"><a name="Page_367" id="Page_367">[Pg 367]</a></span><br />
+Hereditary mingling, mosaic rather than blend, <a href="#Page_13">13</a>.<br />
+<br />
+Hereditary transmission, laws of, <a href="#Page_68">68</a>.<br />
+<br />
+Heredity: and environment, <a href="#Page_295">295</a>;<br />
+<span style="margin-left: 1em;">dual ancestry in, <a href="#Page_6">6</a>;</span><br />
+<span style="margin-left: 1em;">defined, <a href="#Page_1">1</a>;</span><br />
+<span style="margin-left: 1em;">false, <a href="#Page_163">163</a>;</span><br />
+<span style="margin-left: 1em;">human, uncertainty of records, <a href="#Page_98">98</a>;</span><br />
+<span style="margin-left: 1em;">in protozoa, <a href="#Page_22">22</a>, <a href="#Page_23">23</a>;</span><br />
+<span style="margin-left: 1em;">in insanity, importance of, <a href="#Page_261">261</a>;</span><br />
+<span style="margin-left: 1em;">in sexually reproducing forms, <a href="#Page_7">7</a>;</span><br />
+<span style="margin-left: 1em;">in unicellular forms, <a href="#Page_22">22</a>, <a href="#Page_23">23</a>;</span><br />
+<span style="margin-left: 1em;">methods of study, <a href="#Page_14">14</a>, <a href="#Page_15">15</a>;</span><br />
+<span style="margin-left: 1em;">new discoveries in, <a href="#Page_67">67</a>;</span><br />
+<span style="margin-left: 1em;">not a blend, <a href="#Page_13">13</a>;</span><br />
+<span style="margin-left: 1em;">race betterment through, <a href="#Page_289">289</a>.</span><br />
+<br />
+Heritage, blood, <a href="#Page_1">1</a>.<br />
+<br />
+Heron, <a href="#Page_307">307</a>.<br />
+<br />
+Heterozygote: <a href="#Page_80">80</a>;<br />
+<span style="margin-left: 1em;">detection of, <a href="#Page_80">80</a>.</span><br />
+<br />
+Hill-folk, the, <a href="#Page_271">271</a>.<br />
+<br />
+Hodge, <a href="#Page_175">175</a>.<br />
+<br />
+Holmes, <a href="#Page_203">203</a>.<br />
+<br />
+Home, for children, <a href="#Page_338">338</a>.<br />
+<br />
+Homozygote, <a href="#Page_80">80</a>.<br />
+<br />
+Huntington&#8217;s chorea, <a href="#Page_113">113-115</a>, <a href="#Page_243">243</a>, <a href="#Page_325">325</a>.<br />
+<br />
+Huxley, <a href="#Page_195">195</a>, <a href="#Page_205">205</a>.<br />
+<br />
+Hybrids: <a href="#Page_52">52</a>;<br />
+<span style="margin-left: 1em;">whites and negroes, <a href="#Page_297">297</a>, <a href="#Page_298">298</a>.</span><br />
+<br />
+Hypotrichosis, <a href="#Page_113">113</a>.<br />
+<br />
+Hysteria, <a href="#Page_117">117</a>.<br />
+<br />
+<br />
+Ichthyosis, <a href="#Page_65">65</a>.<br />
+<br />
+Ideals, importance of establishing in children, <a href="#Page_223">223</a>.<br />
+<br />
+Idiots, <a href="#Page_244">244</a>.<br />
+<br />
+Imbeciles, <a href="#Page_244">244</a>.<br />
+<br />
+Immigrants, duty of excluding undesirable, <a href="#Page_335">335</a>.<br />
+<br />
+Immigration: and mental unsoundness, <a href="#Page_281">281</a>, <a href="#Page_282">282</a>;<br />
+<span style="margin-left: 1em;">bearing on crime and delinquency, <a href="#Page_280">280</a>;</span><br />
+<span style="margin-left: 1em;">bearing on venereal diseases, <a href="#Page_282">282</a>;</span><br />
+<span style="margin-left: 1em;">importance of restricting, <a href="#Page_283">283</a>, <a href="#Page_335">335</a>.</span><br />
+<br />
+Immortality: of protozoa, <a href="#Page_23">23</a>;<br />
+<span style="margin-left: 1em;">of the race, <a href="#Page_3">3</a>.</span><br />
+<br />
+Immunity, artificial, not inherited, <a href="#Page_155">155</a>.<br />
+<br />
+Inbreeding, in defectives, <a href="#Page_271">271</a>.<br />
+<br />
+Individual, and race, <a href="#Page_3">3</a>.<br />
+<br />
+Inebriate women, offspring of, <a href="#Page_168">168</a>.<br />
+<br />
+Inebriety, constitutional, <a href="#Page_180">180</a>.<br />
+<br />
+Infant mortality, <a href="#Page_149">149</a>.<br />
+<br />
+Infection, prenatal, <a href="#Page_147">147</a>.<br />
+<br />
+Inheritance: and disease, <a href="#Page_146">146</a>;<br />
+<span style="margin-left: 1em;">blended, <a href="#Page_87">87</a>, <a href="#Page_93">93</a>;</span><br />
+<span style="margin-left: 1em;">of tendencies, <a href="#Page_107">107</a>.</span><br />
+<br />
+Inhibitions, <a href="#Page_216">216</a>.<br />
+<br />
+Inhibitors, <a href="#Page_79">79</a>.<br />
+<br />
+Insane, increase in numbers of, <a href="#Page_233">233</a>, <a href="#Page_234">234</a>.<br />
+<br />
+Insanity: <a href="#Page_117">117</a>;<br />
+<span style="margin-left: 1em;">certain forms recessive, <a href="#Page_243">243</a>;</span><br />
+<span style="margin-left: 1em;">eugenical significance of, <a href="#Page_234">234</a>, <a href="#Page_235">235</a>, <a href="#Page_240">240</a>;</span><br />
+<span style="margin-left: 1em;">importance of early diagnosis, <a href="#Page_259">259</a>;</span><br />
+<span style="margin-left: 1em;">some forms not hereditary, <a href="#Page_260">260</a>;</span><br />
+<span style="margin-left: 1em;">types of, <a href="#Page_239">239</a>;</span><br />
+<span style="margin-left: 1em;">prevalence in the United States, <a href="#Page_228">228</a>, <a href="#Page_229">229</a>.</span><br />
+<span class="pagenum"><a name="Page_368" id="Page_368">[Pg 368]</a></span><br />
+Insect colors, effect of temperature, <a href="#Page_129">129</a>.<br />
+<br />
+Instincts: <a href="#Page_203">203</a>;<br />
+<span style="margin-left: 1em;">adjustable, <a href="#Page_203">203</a>;</span><br />
+<span style="margin-left: 1em;">not inherited acquirements, <a href="#Page_144">144</a>;</span><br />
+<span style="margin-left: 1em;">origin of intelligent behavior from, <a href="#Page_203">203</a>, <a href="#Page_204">204</a>.</span><br />
+<br />
+Institutional figures misleading, <a href="#Page_266">266</a>.<br />
+<br />
+Intelligence, <a href="#Page_205">205</a>, <a href="#Page_206">206</a>.<br />
+<br />
+Intelligent behavior, opening up possibilities of, <a href="#Page_204">204</a>.<br />
+<br />
+Ireland, <a href="#Page_171">171</a>.<br />
+<br />
+Irritability, characteristics of living protoplasm, <a href="#Page_197">197</a>.<br />
+<br />
+<br />
+Jennings, <a href="#Page_203">203</a>, <a href="#Page_204">204</a>.<br />
+<br />
+Johnson, <a href="#Page_305">305</a>.<br />
+<br />
+Johnstone, <a href="#Page_245">245</a>, <a href="#Page_319">319</a>, <a href="#Page_320">320</a>, <a href="#Page_321">321</a>.<br />
+<br />
+Jolly, <a href="#Page_243">243</a>.<br />
+<br />
+Jordan, <a href="#Page_4">4</a>, <a href="#Page_299">299</a>.<br />
+<br />
+Jukes, <a href="#Page_270">270</a>.<br />
+<br />
+<br />
+Kallikak family, <a href="#Page_269">269</a>, <a href="#Page_270">270</a>.<br />
+<br />
+Kellicott, <a href="#Page_314">314</a>, <a href="#Page_316">316</a>.<br />
+<br />
+Kellogg, <a href="#Page_299">299</a>.<br />
+<br />
+Keratosis, <a href="#Page_113">113</a>.<br />
+<br />
+Kidney diseases, <a href="#Page_154">154</a>.<br />
+<br />
+Kirby, <a href="#Page_187">187</a>, <a href="#Page_324">324</a>.<br />
+<br />
+Knox, <a href="#Page_256">256</a>.<br />
+<br />
+Kraeplin, <a href="#Page_242">242</a>.<br />
+<br />
+<br />
+Laitinen, <a href="#Page_174">174</a>.<br />
+<br />
+Language, as mental aid, <a href="#Page_206">206</a>, <a href="#Page_207">207</a>.<br />
+<br />
+Lapsed intelligence, theory of, <a href="#Page_145">145</a>.<br />
+<br />
+Larval stages, susceptibility of, <a href="#Page_128">128</a>.<br />
+<br />
+Laws, sterilization, <a href="#Page_323">323</a>, <a href="#Page_327">327</a>, <a href="#Page_329">329</a>.<br />
+<br />
+Lead-poisoning: <a href="#Page_163">163</a>;<br />
+<span style="margin-left: 1em;">experiments on rabbits, <a href="#Page_163">163</a>.</span><br />
+<br />
+Lederbaur, <a href="#Page_131">131</a>.<br />
+<br />
+Legal restraint of defectives limited, <a href="#Page_331">331</a>.<br />
+<br />
+Lens: displaced, <a href="#Page_113">113</a>;<br />
+<span style="margin-left: 1em;">cataract, <a href="#Page_112">112</a>.</span><br />
+<br />
+Leprosy, <a href="#Page_152">152</a>.<br />
+<br />
+Leptinotarsa, production of variations in, <a href="#Page_125">125</a>.<br />
+<br />
+Linden, Countess von, <a href="#Page_129">129</a>.<br />
+<br />
+Linin, <a href="#Page_31">31</a>.<br />
+<br />
+Little&#8217;s disease, <a href="#Page_215">215</a>.<br />
+<br />
+Locomotor ataxia, <a href="#Page_187">187</a>.<br />
+<br />
+Loeb, <a href="#Page_62">62</a>, <a href="#Page_203">203</a>.<br />
+<br />
+Longevity, <a href="#Page_120">120</a>.<br />
+<br />
+Lord Morton&#8217;s mare, <a href="#Page_10">10</a>.<br />
+<br />
+Lorenz, <a href="#Page_113">113</a>, <a href="#Page_114">114</a>, <a href="#Page_115">115</a>.<br />
+<br />
+Low birth-rate, <a href="#Page_308">308</a>.<br />
+<br />
+Lowell, Judge John, <a href="#Page_312">312</a>.<br />
+<br />
+Luetin test, <a href="#Page_188">188</a>.<br />
+<br />
+Lunborg, <a href="#Page_243">243</a>.<br />
+<span class="pagenum"><a name="Page_369" id="Page_369">[Pg 369]</a></span><br />
+<br />
+MacDougal, <a href="#Page_125">125</a>.<br />
+<br />
+Margaret, Mother of Criminals, <a href="#Page_270">270</a>.<br />
+<br />
+Marriage: barriers to, <a href="#Page_331">331</a>;<br />
+<span style="margin-left: 1em;">inter-racial, <a href="#Page_296">296</a>;</span><br />
+<span style="margin-left: 1em;">medical inspection before, <a href="#Page_191">191</a>.</span><br />
+<br />
+Mast, <a href="#Page_203">203</a>.<br />
+<br />
+Maternal impressions, <a href="#Page_159">159-160</a>.<br />
+<br />
+Maturation: <a href="#Page_39">39</a>, <a href="#Page_41">41</a>, <a href="#Page_43">43</a>, <a href="#Page_44">44</a>;<br />
+<span style="margin-left: 1em;">parallel between egg and sperm-cell, <a href="#Page_44">44</a>, <a href="#Page_46">46</a>.</span><br />
+<br />
+Mechanical skill, <a href="#Page_120">120</a>.<br />
+<br />
+Mechanism of heredity, <a href="#Page_22">22</a>, <a href="#Page_25">25</a>, <a href="#Page_26">26</a>, <a href="#Page_28">28</a>, <a href="#Page_29">29</a>, <a href="#Page_30">30</a>, <a href="#Page_35">35</a>, <a href="#Page_37">37</a>, <a href="#Page_40">40-54</a>, <a href="#Page_94">94</a>, <a href="#Page_95">95</a>.<br />
+<br />
+Melancholia and crime, <a href="#Page_279">279</a>.<br />
+<br />
+Memory: <a href="#Page_120">120</a>, <a href="#Page_204">204</a>;<br />
+<span style="margin-left: 1em;">not a complete test of normality, <a href="#Page_268">268</a>, <a href="#Page_269">269</a>.</span><br />
+<br />
+Mendel: <a href="#Page_68">68</a>;<br />
+<span style="margin-left: 1em;">work on peas, <a href="#Page_82">82</a>.</span><br />
+<br />
+Mendelian factors and chromosomes: <a href="#Page_93">93</a>;<br />
+<span style="margin-left: 1em;">inheritance and man, <a href="#Page_97">97</a>;</span><br />
+<span style="margin-left: 1em;">principles, rediscovery of, <a href="#Page_68">68</a>;</span><br />
+<span style="margin-left: 1em;">ratio, cause of, <a href="#Page_71">71</a>.</span><br />
+<br />
+Mendelism, <a href="#Page_67">67</a>, <a href="#Page_69">69</a>.<br />
+<br />
+Mental and nervous defects, <a href="#Page_228">228</a>.<br />
+<br />
+Mental defective: defined, <a href="#Page_255">255</a>;<br />
+<span style="margin-left: 1em;">disproportionate increase in, <a href="#Page_232">232</a>;</span><br />
+<span style="margin-left: 1em;">numbers married, <a href="#Page_231">231</a>, <a href="#Page_232">232</a>;</span><br />
+<span style="margin-left: 1em;">inefficiency of marriage laws concerning, <a href="#Page_315">315</a>.</span><br />
+<br />
+Mental deficiency: not always inherited, <a href="#Page_248">248</a>;<br />
+<span style="margin-left: 1em;">tests for, <a href="#Page_254">254</a>, <a href="#Page_255">255</a>.</span><br />
+<br />
+Mental organization of lower vertebrates, <a href="#Page_205">205</a>.<br />
+<br />
+Mental process as neural process, <a href="#Page_195">195</a>.<br />
+<br />
+Mental unsoundness, <a href="#Page_196">196</a>.<br />
+<br />
+Mentality, inheritance of, <a href="#Page_19">19</a>.<br />
+<br />
+Mentally disordered, cost of caring for, <a href="#Page_257">257</a>, <a href="#Page_258">258</a>.<br />
+<br />
+Mercier, <a href="#Page_279">279</a>.<br />
+<br />
+Merriere&#8217;s disease, <a href="#Page_117">117</a>.<br />
+<br />
+Metazoa, <a href="#Page_28">28</a>.<br />
+<br />
+Metz, <a href="#Page_41">41</a>.<br />
+<br />
+Mice, <a href="#Page_78">78</a>.<br />
+<br />
+Michigan, state report on mentally defective, <a href="#Page_234">234</a>.<br />
+<br />
+Migraine, <a href="#Page_101">101</a>.<br />
+<br />
+Mind, relation to brain, <a href="#Page_195">195</a>.<br />
+<br />
+Mitosis: <a href="#Page_32">32</a>, <a href="#Page_33">33</a>;<br />
+<span style="margin-left: 1em;">meaning of, <a href="#Page_34">34</a>, <a href="#Page_37">37</a>.</span><br />
+<br />
+Mj&ouml;en, <a href="#Page_171">171</a>.<br />
+<br />
+Modifiability of behavior, <a href="#Page_200">200</a>, <a href="#Page_204">204</a>, <a href="#Page_205">205</a>, <a href="#Page_207">207</a>, <a href="#Page_217">217</a>, <a href="#Page_219">219</a>, <a href="#Page_224">224</a>, <a href="#Page_225">225</a>, <a href="#Page_337">337</a>.<br />
+<br />
+Mongolians, <a href="#Page_248">248</a>.<br />
+<br />
+Moral responsibility, <a href="#Page_227">227</a>.<br />
+<br />
+Morgan, C. Lloyd, <a href="#Page_146">146</a>, <a href="#Page_211">211</a>.<br />
+<br />
+Morgan, T. H., <a href="#Page_59">59</a>, <a href="#Page_66">66</a>.<br />
+<br />
+Moron, <a href="#Page_244">244</a>, <a href="#Page_268">268</a>.<br />
+<br />
+Morons and crime, <a href="#Page_268">268</a>.<br />
+<br />
+Mosaic, heredity a, <a href="#Page_13">13</a>.<br />
+<span class="pagenum"><a name="Page_370" id="Page_370">[Pg 370]</a></span><br />
+Motherhood, safeguarding, <a href="#Page_165">165</a>.<br />
+<br />
+Motive, training in, <a href="#Page_220">220</a>.<br />
+<br />
+Mott, <a href="#Page_150">150</a>.<br />
+<br />
+Mulattoes, <a href="#Page_92">92</a>.<br />
+<br />
+Multiple sclerosis, <a href="#Page_64">64</a>, <a href="#Page_117">117</a>.<br />
+<br />
+Muscular atrophy: <a href="#Page_113">113</a>;<br />
+<span style="margin-left: 1em;">Gower&#8217;s, <a href="#Page_65">65</a>.</span><br />
+<br />
+Musical ability, <a href="#Page_120">120</a>.<br />
+<br />
+Mutations: artificial production of, <a href="#Page_125">125</a>;<br />
+<span style="margin-left: 1em;">germinal, <a href="#Page_125">125</a>.</span><br />
+<br />
+Mutilations, non-inheritance of, <a href="#Page_134">134</a>.<br />
+<br />
+Myopia, <a href="#Page_64">64</a>.<br />
+<br />
+<br />
+Naegeli, <a href="#Page_131">131</a>.<br />
+<br />
+Nam family, <a href="#Page_271">271</a>.<br />
+<br />
+Natural selection partly done away with in human society, <a href="#Page_292">292</a>.<br />
+<br />
+Near-sightedness, <a href="#Page_64">64</a>.<br />
+<br />
+Nervous and mental diseases, <a href="#Page_153">153</a>.<br />
+<br />
+Nervous organization, inheritable, <a href="#Page_242">242</a>.<br />
+<br />
+Nervous response, in lower organisms, <a href="#Page_196">196</a>.<br />
+<br />
+Nervous system: mainly inherited, <a href="#Page_210">210</a>, <a href="#Page_216">216</a>;<br />
+<span style="margin-left: 1em;">establishment of pathways in, <a href="#Page_210">210</a>;</span><br />
+<span style="margin-left: 1em;">maladjustments of, <a href="#Page_231">231</a>;</span><br />
+<span style="margin-left: 1em;">special developments in man, <a href="#Page_213">213</a>, <a href="#Page_214">214</a>, <a href="#Page_215">215</a>;</span><br />
+<span style="margin-left: 1em;">units of, <a href="#Page_208">208</a>.</span><br />
+<br />
+Nervous systems of anthropoids, <a href="#Page_214">214</a>.<br />
+<br />
+Neural pathways, not all established at birth, <a href="#Page_217">217</a>.<br />
+<br />
+Neuritis optica, <a href="#Page_65">65</a>.<br />
+<br />
+Neurons, <a href="#Page_208">208</a>.<br />
+<br />
+Neuron theory, <a href="#Page_208">208</a>.<br />
+<br />
+Neuropathic constitution, expression of, <a href="#Page_241">241</a>.<br />
+<br />
+Neuropathic defects, carriers of, <a href="#Page_253">253</a>.<br />
+<br />
+Neuter insects, heredity in, <a href="#Page_136">136</a>, <a href="#Page_137">137</a>.<br />
+<br />
+New characters, origin of, <a href="#Page_138">138</a>.<br />
+<br />
+Newman, <a href="#Page_56">56</a>.<br />
+<br />
+Nicloux, <a href="#Page_172">172</a>.<br />
+<br />
+Night-blindness, <a href="#Page_65">65</a>.<br />
+<br />
+Nilsson-Ehle, <a href="#Page_88">88</a>, <a href="#Page_89">89</a>.<br />
+<br />
+Noguchi, <a href="#Page_186">186</a>.<br />
+<br />
+Nucleolus, <a href="#Page_31">31</a>.<br />
+<br />
+Nucleus, structure of, <a href="#Page_31">31</a>.<br />
+<br />
+Nulliplex character, <a href="#Page_80">80</a>, <a href="#Page_100">100</a>.<br />
+<br />
+<br />
+Obesity, <a href="#Page_120">120</a>, <a href="#Page_154">154</a>.<br />
+<br />
+Offspring: from one parent only, <a href="#Page_5">5</a>;<br />
+<span style="margin-left: 1em;">different from either parent, <a href="#Page_12">12</a>.</span><br />
+<br />
+O&ouml;cyte, primary, secondary, <a href="#Page_44">44</a>.<br />
+<br />
+O&ouml;genesis, <a href="#Page_44">44</a>.<br />
+<br />
+O&ouml;gonia, <a href="#Page_44">44</a>.<br />
+<br />
+Optic nerve, atrophy of, <a href="#Page_64">64</a>.<br />
+<br />
+Organs, formation of, <a href="#Page_36">36</a>.<br />
+<span class="pagenum"><a name="Page_371" id="Page_371">[Pg 371]</a></span><br />
+Origin of sex cells, <a href="#Page_12">12</a>, <a href="#Page_36">36</a>.<br />
+<br />
+Ovaries, transplantation of, <a href="#Page_134">134</a>.<br />
+<br />
+Ovum, <a href="#Page_26">26</a>, <a href="#Page_40">40</a>.<br />
+<br />
+<br />
+Paralysis, general, <a href="#Page_186">186</a>.<br />
+<br />
+Paranoia, <a href="#Page_279">279</a>.<br />
+<br />
+Parent-body and germ distinct, <a href="#Page_12">12</a>.<br />
+<br />
+Parenthood, cultivation of wholesome sentiment toward, <a href="#Page_336">336</a>.<br />
+<br />
+Paresis: <a href="#Page_186">186</a>;<br />
+<span style="margin-left: 1em;">and crime, <a href="#Page_279">279</a>.</span><br />
+<br />
+Parthenogenesis, <a href="#Page_6">6</a>.<br />
+<br />
+Patterson, <a href="#Page_56">56</a>.<br />
+<br />
+Paul, <a href="#Page_163">163</a>.<br />
+<br />
+Pearson, <a href="#Page_150">150</a>, <a href="#Page_151">151</a>, <a href="#Page_179">179</a>, <a href="#Page_296">296</a>, <a href="#Page_307">307</a>.<br />
+<br />
+Peas, <a href="#Page_68">68</a>, <a href="#Page_82">82</a>.<br />
+<br />
+Performance tests, <a href="#Page_256">256</a>.<br />
+<br />
+Peron, <a href="#Page_133">133</a>.<br />
+<br />
+Personality determined by heredity, <a href="#Page_2">2</a>, <a href="#Page_195">195</a>.<br />
+<br />
+Peterson, <a href="#Page_242">242</a>.<br />
+<br />
+Phenotype, <a href="#Page_86">86</a>.<br />
+<br />
+Phillips, <a href="#Page_134">134</a>, <a href="#Page_135">135</a>.<br />
+<br />
+Phototropism, <a href="#Page_198">198</a>.<br />
+<br />
+Pinard, <a href="#Page_165">165</a>.<br />
+<br />
+Pineys, the, <a href="#Page_271">271</a>.<br />
+<br />
+Plato, <a href="#Page_290">290</a>.<br />
+<br />
+Poellman, <a href="#Page_271">271</a>.<br />
+<br />
+Polar bodies, <a href="#Page_44">44</a>, <a href="#Page_45">45</a>.<br />
+<br />
+Polydactyly, <a href="#Page_108">108</a>.<br />
+<br />
+Potato-beetle, production of variations in, <a href="#Page_125">125</a>.<br />
+<br />
+Potts, <a href="#Page_292">292</a>.<br />
+<br />
+Predisposition to disease, <a href="#Page_148">148</a>.<br />
+<br />
+Pregnancy, neglect of mothers during, <a href="#Page_165">165</a>.<br />
+<br />
+Prenatal care: <a href="#Page_336">336</a>;<br />
+<span style="margin-left: 1em;">infection, <a href="#Page_147">147</a>;</span><br />
+<span style="margin-left: 1em;">influence, <a href="#Page_11">11</a>, <a href="#Page_159">159</a>, <a href="#Page_162">162</a>.</span><br />
+<br />
+Prenuptial medical inspection desirable, <a href="#Page_336">336</a>.<br />
+<br />
+Presence and absence theory: <a href="#Page_78">78</a>;<br />
+<span style="margin-left: 1em;">formul&aelig; for man, <a href="#Page_99">99</a>.</span><br />
+<br />
+Primrose, experiments on, <a href="#Page_125">125</a>.<br />
+<br />
+Principles, Mendelian, <a href="#Page_68">68</a>.<br />
+<br />
+Prisoners, many mentally subnormal, <a href="#Page_266">266</a>.<br />
+<br />
+Pronucleus, <a href="#Page_47">47</a>.<br />
+<br />
+Protective coloration, not of somatic origin, <a href="#Page_135">135</a>, <a href="#Page_136">136</a>.<br />
+<br />
+Protoplasm, germinal, <a href="#Page_39">39</a>.<br />
+<br />
+Psychical development, <a href="#Page_196">196</a>, <a href="#Page_203">203</a>, <a href="#Page_205">205</a>, <a href="#Page_206">206</a>, <a href="#Page_213">213</a>, <a href="#Page_215">215</a>.<br />
+<br />
+Pyramidal tracts, <a href="#Page_214">214</a>.<br />
+<br />
+<br />
+Quagga hybrid, <a href="#Page_10">10</a>.<br />
+<br />
+<br />
+Race amalgamation: <a href="#Page_297">297</a>, <a href="#Page_298">298</a>;<br />
+<span style="margin-left: 1em;">deterioration, in a selected population, <a href="#Page_303">303</a>.</span><br />
+<br />
+Racial degeneracy, not curable by improved environment alone, <a href="#Page_294">294</a>.<br />
+<span class="pagenum"><a name="Page_372" id="Page_372">[Pg 372]</a></span><br />
+Ratio: the 1:2:1, <a href="#Page_73">73</a>;<br />
+<span style="margin-left: 1em;">the 3:1, <a href="#Page_77">77</a>;</span><br />
+<span style="margin-left: 1em;">the 9:3:3:1, <a href="#Page_85">85</a>;</span><br />
+<span style="margin-left: 1em;">the 27:9:9:9:3:3:3:1, <a href="#Page_87">87</a>;</span><br />
+<span style="margin-left: 1em;">the 15:1, <a href="#Page_88">88</a>;</span><br />
+<span style="margin-left: 1em;">the 63:1, <a href="#Page_90">90</a>.</span><br />
+<br />
+Rational behavior, <a href="#Page_205">205</a>, <a href="#Page_206">206</a>.<br />
+<br />
+Reason, <a href="#Page_206">206</a>.<br />
+<br />
+Recessiveness: <a href="#Page_74">74</a>;<br />
+<span style="margin-left: 1em;">in man, <a href="#Page_115">115</a>.</span><br />
+<br />
+Records of family traits desirable, <a href="#Page_337">337</a>.<br />
+<br />
+Reduction division, <a href="#Page_41">41</a>, <a href="#Page_42">42</a>.<br />
+<br />
+Reflexes, <a href="#Page_203">203</a>.<br />
+<br />
+Regression, law of, <a href="#Page_17">17</a>.<br />
+<br />
+Renault, <a href="#Page_172">172</a>.<br />
+<br />
+Rentoul, <a href="#Page_232">232</a>.<br />
+<br />
+Reproduction: asexual, <a href="#Page_6">6</a>, <a href="#Page_26">26</a>;<br />
+<span style="margin-left: 1em;">sexual, <a href="#Page_26">26</a>;</span><br />
+<span style="margin-left: 1em;">sexual and variation, <a href="#Page_139">139</a>.</span><br />
+<br />
+Reproductive cells, <a href="#Page_27">27</a>, <a href="#Page_28">28</a>, <a href="#Page_29">29</a>.<br />
+<br />
+Responsibility for conduct, <a href="#Page_195">195</a>.<br />
+<br />
+Rest, importance of, in pregnancy, <a href="#Page_165">165</a>.<br />
+<br />
+Reversion: <a href="#Page_7">7</a>, <a href="#Page_8">8</a>;<br />
+<span style="margin-left: 1em;">and atavism, <a href="#Page_8">8</a>;</span><br />
+<span style="margin-left: 1em;">in guinea-chicken hybrids, <a href="#Page_8">8</a>.</span><br />
+<br />
+Rheotropism, <a href="#Page_198">198</a>.<br />
+<br />
+Rheumatism, <a href="#Page_154">154</a>.<br />
+<br />
+Ritter, <a href="#Page_143">143</a>.<br />
+<br />
+Rogers, <a href="#Page_246">246</a>, <a href="#Page_272">272</a>.<br />
+<br />
+Romanes, <a href="#Page_133">133</a>.<br />
+<br />
+Rosanoff, <a href="#Page_243">243</a>.<br />
+<br />
+Rossolimo, <a href="#Page_256">256</a>.<br />
+<br />
+Rudin, <a href="#Page_243">243</a>.<br />
+<br />
+<br />
+Salpingectomy, <a href="#Page_322">322</a>.<br />
+<br />
+Sanford, <a href="#Page_205">205</a>.<br />
+<br />
+St. Vitus&#8217; dance, <a href="#Page_117">117</a>.<br />
+<br />
+Schulze, <a href="#Page_24">24</a>.<br />
+<br />
+Schuster, <a href="#Page_296">296</a>.<br />
+<br />
+Sclerosis, multiple, <a href="#Page_64">64</a>, <a href="#Page_117">117</a>.<br />
+<br />
+Segregation: in dihybrids, <a href="#Page_84">84</a>;<br />
+<span style="margin-left: 1em;">Mendelian, <a href="#Page_69">69</a>, <a href="#Page_70">70</a>, <a href="#Page_75">75</a>;</span><br />
+<span style="margin-left: 1em;">of defectives, <a href="#Page_318">318</a>.</span><br />
+<br />
+Seguin, <a href="#Page_256">256</a>.<br />
+<br />
+Self-control, importance of, <a href="#Page_221">221</a>, <a href="#Page_267">267</a>, <a href="#Page_268">268</a>, <a href="#Page_284">284</a>, <a href="#Page_286">286</a>, <a href="#Page_287">287</a>.<br />
+<br />
+Sex: and chromosomes, <a href="#Page_59">59</a>;<br />
+<span style="margin-left: 1em;">and heredity, <a href="#Page_53">53</a>;</span><br />
+<span style="margin-left: 1em;">cells of Volvox, <a href="#Page_25">25</a>;</span><br />
+<span style="margin-left: 1em;">chromosome, <a href="#Page_57">57</a>, <a href="#Page_58">58</a>;</span><br />
+<span style="margin-left: 1em;">determination, <a href="#Page_55">55</a>;</span><br />
+<span style="margin-left: 1em;">differentiation and X-element, <a href="#Page_60">60</a>;</span><br />
+<span style="margin-left: 1em;">evolution of, <a href="#Page_25">25-30</a>;</span><br />
+<span style="margin-left: 1em;">hygiene, question of school instruction in, <a href="#Page_285">285</a>;</span><br />
+<span style="margin-left: 1em;">in certain insects, <a href="#Page_56">56</a>;</span><br />
+<span style="margin-left: 1em;">linked characters, <a href="#Page_60">60</a>, <a href="#Page_65">65</a>;</span><br />
+<span style="margin-left: 1em;">not a necessary factor in heredity, <a href="#Page_6">6</a>;</span><br />
+<span style="margin-left: 1em;">problem, knowledge alone not sufficient, <a href="#Page_286">286</a>.</span><br />
+<br />
+Sexual vice, <a href="#Page_284">284</a>.<br />
+<br />
+Sharp, <a href="#Page_322">322</a>.<br />
+<br />
+Simplex character, <a href="#Page_80">80</a>, <a href="#Page_99">99</a>.<br />
+<br />
+Skill, non-transference in brain, <a href="#Page_212">212</a>, <a href="#Page_213">213</a>.<br />
+<br />
+Skin, color of, <a href="#Page_92">92</a>.<br />
+<span class="pagenum"><a name="Page_373" id="Page_373">[Pg 373]</a></span><br />
+Smallpox, <a href="#Page_152">152</a>.<br />
+<br />
+Social maladies, prevention of, <a href="#Page_293">293</a>.<br />
+<br />
+Softening of the brain, <a href="#Page_186">186</a>.<br />
+<br />
+Soma, <a href="#Page_28">28</a>.<br />
+<br />
+Spermatid, <a href="#Page_43">43</a>.<br />
+<br />
+Spermatocyte, primary, secondary, <a href="#Page_43">43</a>.<br />
+<br />
+Spermatogenesis, <a href="#Page_42">42</a>.<br />
+<br />
+Spermatogonium, <a href="#Page_43">43</a>.<br />
+<br />
+Spermatazoon: <a href="#Page_26">26</a>, <a href="#Page_40">40</a>;<br />
+<span style="margin-left: 1em;">a cell, <a href="#Page_22">22</a>;</span><br />
+<span style="margin-left: 1em;">formation of, <a href="#Page_43">43</a>;</span><br />
+<span style="margin-left: 1em;">structure of, <a href="#Page_43">43</a>.</span><br />
+<br />
+Spindle, in cell-division, <a href="#Page_32">32</a>.<br />
+<br />
+Spottedness of hair-coat, <a href="#Page_113">113</a>.<br />
+<br />
+Sprague, <a href="#Page_281">281</a>, <a href="#Page_305">305</a>.<br />
+<br />
+Starfish, training a, <a href="#Page_204">204</a>.<br />
+<br />
+Statistical methods, <a href="#Page_15">15</a>.<br />
+<br />
+Statistics, trustworthy needed, <a href="#Page_334">334</a>.<br />
+<br />
+Stature, inheritance of, <a href="#Page_17">17</a>.<br />
+<br />
+Stereotropism, <a href="#Page_198">198</a>.<br />
+<br />
+Sterility, <a href="#Page_182">182</a>.<br />
+<br />
+Sterilization: <a href="#Page_322">322</a>;<br />
+<span style="margin-left: 1em;">in epilepsy, <a href="#Page_326">326</a>;</span><br />
+<span style="margin-left: 1em;">laws, <a href="#Page_323">323</a>;</span><br />
+<span style="margin-left: 1em;">laws, on trial, <a href="#Page_329">329</a>;</span><br />
+<span style="margin-left: 1em;">laws, states having, <a href="#Page_327">327</a>.</span><br />
+<br />
+Stevens, <a href="#Page_41">41</a>.<br />
+<br />
+Stockard, <a href="#Page_174">174-178</a>.<br />
+<br />
+Strength, muscular, <a href="#Page_120">120</a>.<br />
+<br />
+Stripes, reversionary, <a href="#Page_8">8</a>.<br />
+<br />
+Stutzman, <a href="#Page_305">305</a>.<br />
+<br />
+Sullivan, <a href="#Page_168">168</a>.<br />
+<br />
+Superior strains, conservation of, <a href="#Page_157">157</a>.<br />
+<br />
+Synapse, <a href="#Page_210">210</a>.<br />
+<br />
+Synapsis, <a href="#Page_41">41</a>, <a href="#Page_42">42</a>.<br />
+<br />
+Syndactyly, <a href="#Page_65">65</a>, <a href="#Page_108">108</a>, <a href="#Page_111">111</a>.<br />
+<br />
+Syphilis: <a href="#Page_184">184-190</a>;<br />
+<span style="margin-left: 1em;">and prostitutes, <a href="#Page_185">185</a>;</span><br />
+<span style="margin-left: 1em;">cerebro-spinal form, <a href="#Page_189">189-190</a>;</span><br />
+<span style="margin-left: 1em;">prenuptial inspection for, <a href="#Page_190">190-192</a>;</span><br />
+<span style="margin-left: 1em;">prevalence, <a href="#Page_186">186</a>;</span><br />
+<span style="margin-left: 1em;">stages of, <a href="#Page_185">185</a>;</span><br />
+<span style="margin-left: 1em;">tests for, <a href="#Page_188">188</a>.</span><br />
+<br />
+Syphilitics: children of, <a href="#Page_187">187</a>, <a href="#Page_188">188</a>;<br />
+<span style="margin-left: 1em;">married, <a href="#Page_190">190</a>.</span><br />
+<br />
+<br />
+Tabes dorsalis, <a href="#Page_186">186</a>.<br />
+<br />
+Taints, <a href="#Page_101">101</a>.<br />
+<br />
+Talent, inheritance of, <a href="#Page_212">212</a>.<br />
+<br />
+Taylor, <a href="#Page_297">297</a>.<br />
+<br />
+Telegony, alleged cases of, <a href="#Page_10">10</a>.<br />
+<br />
+Temperament, inheritance of, <a href="#Page_19">19</a>.<br />
+<br />
+Thermotropism, <a href="#Page_198">198</a>.<br />
+<br />
+Thigmotropism, <a href="#Page_198">198</a>.<br />
+<br />
+Third generation, segregation in, <a href="#Page_69">69</a>.<br />
+<br />
+Thomsen&#8217;s disease, <a href="#Page_118">118</a>.<br />
+<br />
+Thomson, <a href="#Page_55">55</a>.<br />
+<br />
+Thorndike, <a href="#Page_296">296</a>.<br />
+<span class="pagenum"><a name="Page_374" id="Page_374">[Pg 374]</a></span><br />
+Tower, <a href="#Page_125">125</a>.<br />
+<br />
+Training of children: and heredity, <a href="#Page_218">218</a>;<br />
+<span style="margin-left: 1em;">faults in, <a href="#Page_221">221</a>, <a href="#Page_222">222</a>.</span><br />
+<br />
+Transmission, not necessarily inheritance, <a href="#Page_163">163</a>.<br />
+<br />
+Tredgold, <a href="#Page_170">170</a>.<br />
+<br />
+Treponema pallidum, <a href="#Page_185">185</a>.<br />
+<br />
+Tribe of Ishmael, <a href="#Page_271">271</a>.<br />
+<br />
+Tropic responses: often purposeful, <a href="#Page_201">201</a>;<br />
+<span style="margin-left: 1em;">uncertainties in, <a href="#Page_202">202</a>.</span><br />
+<br />
+Tropisms: <a href="#Page_197">197</a>;<br />
+<span style="margin-left: 1em;">complications in, <a href="#Page_200">200</a>;</span><br />
+<span style="margin-left: 1em;">in plants and animals, <a href="#Page_198">198</a>;</span><br />
+<span style="margin-left: 1em;">relations to reflex actions and instincts, <a href="#Page_203">203</a>.</span><br />
+<br />
+Tschermak, <a href="#Page_68">68</a>.<br />
+<br />
+Tuberculosis, <a href="#Page_118">118</a>, <a href="#Page_148">148-160</a>, <a href="#Page_162">162</a>.<br />
+<br />
+Twins: identical, <a href="#Page_55">55</a>;<br />
+<span style="margin-left: 1em;">sex of, <a href="#Page_55">55</a>.</span><br />
+<br />
+Typhoid, <a href="#Page_152">152</a>.<br />
+<br />
+<br />
+Unemployed, frequently morons, <a href="#Page_280">280</a>.<br />
+<br />
+Unfit, elimination of, urgent, <a href="#Page_313">313</a>.<br />
+<br />
+Unit-character: <a href="#Page_12">12</a>;<br />
+<span style="margin-left: 1em;">inheritance of, <a href="#Page_13">13</a>.</span><br />
+<br />
+Unicellular organisms: <a href="#Page_21">21</a>;<br />
+<span style="margin-left: 1em;">inheritance in, <a href="#Page_22">22</a>, <a href="#Page_23">23</a>.</span><br />
+<br />
+Use and disuse, <a href="#Page_122">122</a>.<br />
+<br />
+<br />
+Van Ingen, <a href="#Page_167">167</a>.<br />
+<br />
+Vasectomy, <a href="#Page_322">322</a>.<br />
+<br />
+Venereal disease, <a href="#Page_182">182</a>.<br />
+<br />
+Virchow, <a href="#Page_147">147</a>.<br />
+<br />
+Voison, <a href="#Page_133">133</a>.<br />
+<br />
+Volitions as tropisms, <a href="#Page_199">199</a>.<br />
+<br />
+Volvox, <a href="#Page_25">25</a>, <a href="#Page_26">26</a>, <a href="#Page_27">27</a>.<br />
+<br />
+<br />
+War, eugenical effects of, <a href="#Page_299">299</a>.<br />
+<br />
+Wasserman, provocative, <a href="#Page_189">189</a>.<br />
+<br />
+Wasserman test, <a href="#Page_188">188</a>, <a href="#Page_189">189</a>.<br />
+<br />
+Webbed digits, <a href="#Page_65">65</a>.<br />
+<br />
+Weeks, <a href="#Page_251">251</a>, <a href="#Page_252">252</a>, <a href="#Page_253">253</a>, <a href="#Page_291">291</a>.<br />
+<br />
+West, <a href="#Page_167">167</a>.<br />
+<br />
+Wheat, <a href="#Page_75">75</a>, <a href="#Page_81">81</a>, <a href="#Page_88">88</a>.<br />
+<br />
+Whetham, <a href="#Page_314">314</a>, <a href="#Page_316">316</a>.<br />
+<br />
+Whitman, <a href="#Page_145">145</a>.<br />
+<br />
+Wilmarth, <a href="#Page_243">243</a>, <a href="#Page_245">245</a>, <a href="#Page_274">274</a>, <a href="#Page_291">291</a>.<br />
+<br />
+Wilson, <a href="#Page_59">59</a>, <a href="#Page_62">62</a>, <a href="#Page_94">94</a>, <a href="#Page_95">95</a>.<br />
+<br />
+Woods, <a href="#Page_296">296</a>.<br />
+<br />
+<br />
+X-element, <a href="#Page_57">57</a>, <a href="#Page_58">58</a>.<br />
+<br />
+<br />
+Zebra hybrids, <a href="#Page_10">10</a>.<br />
+<br />
+Zeros, the, <a href="#Page_271">271</a>.<br />
+<br />
+Zygote: <a href="#Page_26">26</a>, <a href="#Page_27">27</a>;<br />
+<span style="margin-left: 1em;">chromosomes of, <a href="#Page_40">40</a>.</span><br />
+</p>
+
+
+
+<p>&nbsp;</p><p>&nbsp;</p>
+<hr style="width: 50%;" />
+<p><strong>Footnotes:</strong></p>
+
+<p><a name='f_1' id='f_1' href='#fna_1'>[1]</a> The reader desiring more detailed information will find fuller
+discussions in the following:</p>
+
+<p>Wilson, E. B.: <i>Recent Researches on the Determination and Heredity of
+Sex</i>. Science, January 8, 1909.</p>
+
+<p>Wilson, E. B.: <i>The Chromosomes in Relation to the Determination of Sex</i>.
+Science Progress, April, 1910.</p>
+
+<p>Guyer, M. F.: <i>Recent Progress in Some Lines of Cytology</i>. Transactions of
+the American Microscopical Society, April, 1911.</p>
+
+<p>Morgan, T. H.: <i>Heredity and Sex</i>. Columbia University Press, 1913.</p>
+
+<p><a name='f_2' id='f_2' href='#fna_2'>[2]</a> A translation of Mendel&#8217;s original papers will be found in <i>Mendel&#8217;s
+Principles of Heredity</i>, by W. Bateson.</p>
+
+<p><a name='f_3' id='f_3' href='#fna_3'>[3]</a> <i>Heredity of Skin Color in Negro and White Crosses</i>: Publication No.
+188, of the <i>Carnegie Institution of Washington</i>.</p>
+
+<p><a name='f_4' id='f_4' href='#fna_4'>[4]</a> Whitman, C. O.: <i>Animal Behavior, Biological Lectures</i>, Marine
+Biological Laboratory, 1898.</p>
+
+<p><a name='f_5' id='f_5' href='#fna_5'>[5]</a> <i>The Fight Against Tuberculosis and the Death Rate from Phthisis</i>,
+London, Dulau &amp; Co., 1911.</p>
+
+<p><a name='f_6' id='f_6' href='#fna_6'>[6]</a> Forel, August: <i>The Sexual Question</i>, p. 268.</p>
+
+<p><a name='f_7' id='f_7' href='#fna_7'>[7]</a> Loc. cit. p. 251.</p>
+
+<p><a name='f_8' id='f_8' href='#fna_8'>[8]</a> In this connection it is instructive to note from a Michigan state
+report, just off the press, that, among 4,917 insane individuals
+concerning whom satisfactory information was obtained, 65.4 per cent. &#8220;had
+among their ancestors or family such hereditary influences as insanity,
+apoplexy or paralysis, psychopathic abnormalities or alcoholism.&#8221; See
+<i>Report of the Commission to Investigate the Extent of Feeble-mindedness,
+Epilepsy, Insanity and Other Conditions of Mental Defectiveness in
+Michigan</i>. Wynkoop Hollenbeck Crawford Co., State Printers, Lansing,
+Michigan, 1915.</p>
+
+<p><a name='f_9' id='f_9' href='#fna_9'>[9]</a> <i>Feeble-mindedness; Its Causes and Consequences</i>, by Henry H. Goddard,
+The Macmillan Company, 1914.</p>
+
+<p><a name='f_10' id='f_10' href='#fna_10'>[10]</a> <i>The Binet-Simon Measuring Scale for Intelligence</i>, by Henry H.
+Goddard, 1911. The Training School, Vineland, N. J. Price 15 cents.</p>
+
+<p><a name='f_11' id='f_11' href='#fna_11'>[11]</a> &#8220;Tests for Mental Defects,&#8221; by Howard A. Knox, <i>Journal of Heredity</i>,
+March, 1914. See also Knox: <i>Journal of the American Medical Association</i>,
+1914.</p>
+
+<p><a name='f_12' id='f_12' href='#fna_12'>[12]</a> <i>The Individual Delinquent</i>, by William Healy, M. D. Little, Brown &amp;
+Co., Boston.</p>
+
+<p><a name='f_13' id='f_13' href='#fna_13'>[13]</a> <i>The Individual Delinquent</i>, by William Healy, M. D. Little, Brown &amp;
+Co., Boston.</p>
+
+<p><a name='f_14' id='f_14' href='#fna_14'>[14]</a> The Psycopathic Laboratory in connection with the Juvenile Court of
+Chicago.</p>
+
+<p><a name='f_15' id='f_15' href='#fna_15'>[15]</a> See &#8220;The Foreign Born in the United States.&#8221; <i>The National Geographic
+Magazine</i>, September, 1914.</p>
+
+<p><a name='f_16' id='f_16' href='#fna_16'>[16]</a> See First Report of the Committee of the Eugenic Section of the
+American Breeders&#8217; Association, &#8220;On Immigration&#8221;, <i>American Breeders&#8217;
+Magazine</i>, Vol. III, No. 4, 1912. Also Second Report of same, <i>The Journal
+of Heredity</i>, July, 1914.</p>
+
+<p><a name='f_17' id='f_17' href='#fna_17'>[17]</a> &#8220;The Negro and His Health Problems,&#8221; <i>Medical Record</i>, September 12,
+1912.</p>
+
+<p><a name='f_18' id='f_18' href='#fna_18'>[18]</a> See D. S. Jordan, <i>The Human Harvest</i>, or V. L. Kellogg, <i>Eugenics
+and Militarism</i>.</p>
+
+<p><a name='f_19' id='f_19' href='#fna_19'>[19]</a> For arguments indicating the superior eugenical fitness of college
+graduates see &#8220;Wellesley&#8217;s Birth-Rate,&#8221; by Roswell H. Johnson and Bertha
+Stutzman, <i>The Journal of Heredity</i>, June, 1915. See also, &#8220;Education and
+Race Suicide,&#8221; by Robert J. Sprague, <i>ibid.</i>, April, 1915.</p>
+
+<p><a name='f_20' id='f_20' href='#fna_20'>[20]</a> Since the present manuscript went to press an excellent government
+report (<i>Insane and Feeble-Minded in Institutions in 1910</i>, Department of
+Commerce, Bureau of the Census, 1914, Washington, D. C.) has appeared. In
+it one finds the estimate that not over one-tenth of our feeble-minded are
+being cared for in special institutions.</p>
+
+<p><a name='f_21' id='f_21' href='#fna_21'>[21]</a> For summaries of existing sterilization laws and statements of the
+issues involved see (1) <i>The Legal, Legislative, and Administrative
+Aspects of Sterilisation</i>, Bulletin 10B, February 3, 1914, Eugenics Record
+Office, Cold Spring Harbor, N. Y.; (2) <i>Sterilisation of Criminals</i>,
+Report of Committee H of the American Institute of Criminal Law and
+Criminology, Bulletin No. XV, September, 1914.</p>
+
+
+
+
+
+
+
+
+
+<pre>
+
+
+
+
+
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+</body>
+</html>
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+The Project Gutenberg EBook of Being Well-Born, by Michael F. Guyer
+
+This eBook is for the use of anyone anywhere at no cost and with
+almost no restrictions whatsoever.  You may copy it, give it away or
+re-use it under the terms of the Project Gutenberg License included
+with this eBook or online at www.gutenberg.org
+
+
+Title: Being Well-Born
+       An Introduction to Eugenics
+
+Author: Michael F. Guyer
+
+Editor: M. V. O'Shea
+
+Release Date: May 21, 2012 [EBook #39751]
+
+Language: English
+
+Character set encoding: ASCII
+
+*** START OF THIS PROJECT GUTENBERG EBOOK BEING WELL-BORN ***
+
+
+
+
+Produced by Bryan Ness and the Online Distributed
+Proofreading Team at http://www.pgdp.net (This file was
+produced from images generously made available by The
+Internet Archive.)
+
+
+
+
+
+
+
+
+
+BEING WELL-BORN
+
+
+
+
+  BEING WELL-BORN
+
+  AN INTRODUCTION TO EUGENICS
+
+
+  _By_
+  MICHAEL F. GUYER, PH. D.
+  Professor of Zoology, The University of Wisconsin
+
+
+  Childhood and Youth Series
+
+  _Edited by_ M. V. O'SHEA
+  Professor of Education, The University of Wisconsin
+
+
+  INDIANAPOLIS
+  THE BOBBS-MERRILL COMPANY
+  PUBLISHERS
+
+
+
+
+  COPYRIGHT 1916
+  THE BOBBS-MERRILL COMPANY
+
+  PRESS OF
+  BRAUNWORTH & CO.
+  BOOKBINDERS AND PRINTERS
+  BROOKLYN, N. Y.
+
+
+
+
+TO MY WIFE
+
+HELEN M. GUYER
+
+
+
+
+EDITOR'S INTRODUCTION
+
+
+The writer recalls that when he was a young boy, he heard the grown-up
+people in the community earnestly and incessantly debating the question:
+Does heredity play a greater part in shaping one's mind and body than does
+his environment? From that day to this he has listened to men and women in
+every walk of life discussing the relation of heredity to environment in
+determining human traits. Teachers and parents are constantly asking: "Are
+such and such characteristics in my children due to their inheritance or
+to the way they have been trained?" Students of juvenile delinquency and
+of mental defect and deficiency are searching everywhere for light on this
+matter. It is not to be wondered at that practically all people are
+peculiarly interested in this problem, since it concerns intimately one's
+personal traits, and it constantly confronts any one who is responsible
+for the care and culture of the young.
+
+It is suggestive to note how people differ in their views regarding the
+extent to which a child's physical and mental qualities and capacities are
+fixed definitely by his inheritance. The writer has often heard students
+in university classes discuss the subject; and their handling of the
+problem has shown how superficially and even superstitiously most persons
+regard the mechanism and functions of heredity. It is significant also to
+observe what extreme views many people hold regarding the possibility of
+affecting a child's traits and abilities by subjecting him to specific
+influences during his prenatal life. In any group of one hundred persons
+chosen at random, probably seventy-five will believe in specific prenatal
+influence. Many of them will believe in birthmarks due to peculiar
+experiences of the mother. A popular book recently published asserts among
+other things that if a mother will look upon beautiful pictures and listen
+to good music during the prenatal period of her child, the latter will
+possess esthetic traits and interests in high degree. On the other hand,
+people generally do not seem to think that degenerate parents beget only
+degenerate children. Alcoholics, feeble-minded persons and the like are
+permitted to bring children into the world.
+
+Very few people have any precise knowledge of the mechanism of heredity.
+The whole thing is inscrutable to them, and is shrouded in mystery.
+Superstition flourishes among even intelligent persons in respect to
+heredity, and errors due to education, and tragedies resulting from
+vicious social organization are all alike ascribed to its uncontrollable
+forces. Most people are none the wiser because they do not know to what
+extent the physical and mental defects and deviations of individuals are
+due to inheritance or to the malign influences of the individual's
+environment and training.
+
+Professor Guyer, who has studied the whole problem in a thoroughgoing,
+scientific way, has prepared this book with a view to illuminating some of
+the mysteries that surround the subject of heredity, and to dispelling
+the illusions that persist regarding it. He shows the method which nature
+follows in the development of the individual. He presents the laws which
+have become established respecting the extent to which and the manner in
+which immediate and remote ancestors contribute to the child's physical
+and mental organism. He answers many questions which those who are engaged
+in social work or in education in the home or the school are asking
+to-day. He discusses subjects upon which every serious-minded person
+wishes to be informed. He has thus made a book which is both of
+theoretical and of practical interest.
+
+He has written in a style which should make his book attractive to the
+parent and the teacher as well as to the student of the complicated
+mechanism of inheritance. Only a few special terms are used, and these
+should not give any reader trouble, because the treatment throughout is so
+concrete that the meaning of the terms will be easily grasped. Further,
+the book is illustrated, with many attractive and instructive
+illustrations which will show at a glance the working of the principles of
+inheritance which are developed in the text.
+
+This book may be heartily commended to all who are interested in questions
+of human nature, education and social reform. It should enable the parent,
+the teacher and the legislator to understand more clearly than most of
+them now do in how far children's traits and possibilities are or can be
+fixed by inheritance as contrasted with environmental conditions and
+nurture in home, school, church and institutional life.
+
+M. V. O'SHEA.
+
+Madison, Wisconsin.
+
+
+
+
+PREFACE
+
+
+One of the most significant processes at work in society to-day is the
+awakening of the civilized world to the rights of the child; and it is
+coming to be realized that its right of rights is that of being well-born.
+Any series of publications, therefore, dealing primarily with the problems
+of child nature may very fittingly be initiated by a discussion of the
+factor of well-nigh supreme importance in determining this nature,
+heredity.
+
+No principles have more direct bearing on the welfare of man than those of
+heredity, and yet on scarcely any subject does as wide-spread ignorance
+prevail. This is due in part to the complexity of the subject, but more to
+the fact that in the past no clear-cut methods of attacking the manifold
+problems involved had been devised. Happily this difficulty has at least
+in part been overcome.
+
+It is no exaggeration to say that during the last fifteen years we have
+made more progress in measuring the extent of inheritance and in
+determining its elemental factors than in all previous time. Instead of
+dealing wholly now with vague general impressions and speculations,
+certain definite principles of genetic transmission have been disclosed.
+And since it is becoming more and more apparent that these hold for man as
+well as for plants and animals in general, we can no longer ignore the
+social responsibilities which the new facts thrust upon us.
+
+Since what a child becomes is determined so largely by its inborn
+capacities it is of the greatest importance that teachers and parents
+realize something of the nature of such aptitudes before they begin to
+awaken them. For education consists in large measure in applying the
+stimuli necessary to set going these potentialities and of affording
+opportunity for their expression. Of the good propensities, some will
+require merely the start, others will need to be fostered and coaxed into
+permanence through the stereotyping effects of proper habits; of the
+dangerous or bad, some must be kept dormant by preventing improper
+stimulation, others repressed by the cultivation of inhibitive tendencies,
+and yet others smothered or excluded by filling their place with desirable
+traits before they themselves come into expression.
+
+We must see clearly, furthermore, that even the best of pedagogy and
+parental training has obvious limits. Once grasp the truth that a child's
+fate in life is frequently decided long before birth, and that no amount
+of food or hospital service or culture or tears will ever wholly make good
+the deficiencies of bad "blood," or in the language of the biologist, a
+faulty germ-plasm, and the conviction must surely be borne home to the
+intelligent members of society that one thing of superlative importance in
+life is the making of a wise choice of a marriage mate on the one hand,
+and the prevention of parenthood to the obviously unfit on the other.
+
+In the present volume it is intended to examine into the natural
+endowment of the child. And since full comprehension of it requires some
+understanding of the nature of the physical mechanism by which hereditary
+traits are handed on from generation to generation, a small amount of
+space is given to this phase. Then, that the reader may appreciate to
+their fullest extent the facts gathered concerning man, a review of the
+more significant principles of genetics as revealed through experiments in
+breeding plants and animals has been undertaken. The main applications of
+these principles to man is pointed out in a general discussion of human
+heredity. Finally, inasmuch as all available data indicate that the fate
+of our very civilization hangs on the issue, the work concludes with an
+account of the new science of eugenics which is striving for the
+betterment of the race by determining and promulgating the laws of human
+inheritance so that mankind may intelligently go about conserving good and
+repressing bad human stocks.
+
+In order to eliminate as many errors as possible and to avoid oversights I
+have submitted various chapters to certain of my colleagues and friends
+who are authorities in the special field treated therein. While these
+gentlemen are in no way responsible for the material of any chapter they
+have added greatly to the value of the whole by their suggestions and
+comments. Thus I am indebted to Professor Leon J. Cole for reading the
+entire manuscript; to Professors A. S. Pearse and F. C. Sharp for reading
+Chapter VII; to Professor C. R. Bardeen for reading special parts; to
+Doctor J. S. Evans for reading Chapter VI and part of V; to Doctor W. F.
+Lorenz, of the Mendota Hospital, for reading Chapter VIII; to Judge E. Ray
+Stevens for reading Chapter IX, and to Helen M. Guyer for several readings
+of the entire manuscript.
+
+Grateful acknowledgment is made to all of these readers, to various
+publishers and periodicals for the use of certain of the illustrations, to
+the authors of the numerous books and papers from which much of the
+material in such a work as this must necessarily be selected, and to my
+artist, Miss H. J. Wakeman, for her painstaking endeavors to make her work
+conform to my ideas of what each diagram should show.
+
+M. F. G.
+
+
+
+
+CONTENTS
+
+
+  CHAPTER                                                             PAGE
+
+  I HEREDITY                                                             1
+
+  Blood heritage--Kind determined by origin--Ancestry a network--
+  Ancestry in royalty--Offspring derived from one parent only--Dual
+  ancestry an aid in studying heredity--Reversion--Telegony--
+  Prenatal influences apart from heredity--Parent body and germ not
+  identical--A hereditary character defined--Hereditary mingling a
+  mosaic rather than a blend--Determiners of characters, not
+  characters themselves, transmitted--Our knowledge of heredity
+  derived along three lines--The method of experimental breeding--
+  The statistical method--Galton's law of regression--Correlations
+  between parents and offspring--The biometrical method,
+  statistical, not physiological--Mental as well as physical
+  qualities inheritable.
+
+
+  II THE BEARERS OF THE HERITAGE                                        20
+
+  The cell the unit of structure--Unicellular organisms--Importance
+  of cell-theory--Heredity in unicellular forms--Reproduction and
+  heredity in colonial protozoa--Conjugation--Specialization of
+  sex-cells--The fertilized ovum--Advancement seen in the Volvox
+  colony--Natural death--Specialization in higher organisms--Sexual
+  phenomena in higher forms--Cell-division--Chromosomes constant in
+  number and appearance--Significance of the chromosomes--Cleavage
+  of the egg--Chief processes operative in building the body--The
+  origin of the new germ-cells--Significance of the early setting
+  apart of the germ-cells--Individuality of chromosomes--Pairs of
+  chromosomes--Reduction of the number of chromosomes by one-half--
+  Maturation of the sperm-cell--Maturation of the egg-cell--Parallel
+  between the two processes--Fertilization--Significance of the
+  behavior of the chromosomes--A single set of chromosomes
+  sufficient for the production of an organism--The duality of the
+  body and the singleness of the germ--The cytoplasm in
+  inheritance--Chromosomes possibly responsible for the
+  distinctiveness of given characters--Sex and heredity--Many
+  theories of sex determination--The sex-chromosome--Sex-linked
+  characters in man--In lower forms.
+
+  III MENDELISM                                                         67
+
+  New discoveries in the field of heredity--Mendel--Rediscovery of
+  Mendelian principles--Independence of inheritable characters--
+  Illustration in the Andalusian fowl--The cause of the ratio--
+  Verification of the hypothesis--Dominant and recessive--
+  Segregation in the next generation--Illustrated in guinea-pigs--
+  Terminology--The theory of presence and absence--Additional
+  terminology--Dominance not always complete--Modifications of
+  dominance--Mendel's own work--Dihybrids--Getting new combinations
+  of characters--Segregations of the determiners--Four kinds of
+  gametes in each sex--The 9:3:3:1 ratio--Phenotype and genotype--
+  The question of blended inheritance--Nilsson-Ehle's discoveries--
+  Such cases easily mistaken for true blends--Skin-color in man--
+  Questionable if real blends exist--The place of the Mendelian
+  factors in the germ-cell--Parallel between the behavior of
+  Mendelian factors and chromosomes--A single chromosome not
+  restricted to carrying a single determiner.
+
+  IV MENDELISM IN MAN                                                   97
+
+  Probably applicable to many characters in man--Difficult to get
+  correct data--A generalized presence-absence formula--Indications
+  of incomplete dominance--Why after the first generation only half
+  the children may show the dominant character--Eye-color in man--
+  Hair-color--Hair-shape--Irregularities--Digital malformations--Eye
+  defects--Other defects inherited as dominants--Recessive
+  conditions more difficult to deal with--Albinism--Other recessive
+  conditions in man--Breeding out defects--Other inheritable
+  conditions in man.
+
+  V ARE MODIFICATIONS ACQUIRED DIRECTLY BY THE BODY INHERITED?         121
+
+  Which new characters are inherited?--Examples of somatic
+  modifications--Use and disuse--The problem stated--Special
+  conditions in mammals--Three fundamental questions--External
+  influences may directly affect the germ-cells--Such effects
+  improbable in warm-blooded animals--Poisons may affect the
+  germ-plasm--How can somatic modifications be registered in
+  germ-cells?--Persistence of Mendelian factors argues against such
+  a mode of inheritance--Experiments on insects--On plants--On
+  vertebrates--Epilepsy in guinea-pigs--Effects of mutilations not
+  inherited--Transplantation of gonads--Effects of body on germ,
+  general not specific--Certain characters inexplicable as inherited
+  somatic acquirements--Neuter insects--Origin of new characters in
+  germinal variation--Sexual reproduction in relation to new
+  characters--Many features of an organism characterized by
+  utility--Germinal variation a simpler and more inclusive
+  explanation--Analysis of cases--Effects of training--Instincts--
+  Disease--Reappearance not necessarily inheritance--Prenatal
+  infection not inheritance--Inheritance of a predisposition not
+  inheritance of a disease--Tuberculosis--Two individuals of
+  tubercular stock should not marry--Special susceptibility less of
+  a factor in many diseases--Deaf-mutism--Gout--Nervous and mental
+  diseases--Other disorders which have hereditary aspects--Induced
+  immunity not inherited--Social, ethical and educational
+  significance of non-inheritance of somatic modifications--No cause
+  for discouragement--Improved environment will help conserve
+  superior strains when they do appear.
+
+  VI PRENATAL INFLUENCES                                               151
+
+  All that a child possesses at birth not necessarily hereditary--
+  The myth of maternal impressions--Injurious prenatal influences--
+  Lead poisoning--The expectant mother should have rest--Too short
+  intervals between children--Expectant mothers neglected--
+  Alcoholism--Unreliability of most data--Alcohol a germinal and
+  fetal poison--Various views of specialists on the effects of
+  alcoholism on progeny--The affinity of alcohol for germinal
+  tissue--Innate degeneracy versus the effects of alcohol--
+  Experimental alcoholism in lower animals--Further remarks on the
+  situation in man--Much inebriety in man due to defective nervous
+  constitution--Factors to be reckoned with in the study of
+  alcoholism--Venereal diseases--The seriousness of the situation--
+  Infantile blindness--Syphilis--Some of the effects--A blood test--
+  Many syphilitics married--Why permit existing conditions to
+  continue?--Ante-nuptial medical inspection--The perils of venereal
+  disease must be prevented at any cost--Bad environment can wreck
+  good germ-plasm.
+
+  VII RESPONSIBILITY FOR CONDUCT                                       195
+
+  All mental process accompanied by neural process--Gradations in
+  nervous response from lower organisms to man--Behavior of many
+  animals often an automatic adjustment to simple external agents--
+  Tropisms--Certain apparently complex volitions probably only
+  tropisms--Complicating factors--Many tropic responses apparently
+  purposeful--Tropisms grade into reflex actions and instincts--
+  Adjustability of instincts opens the way for intelligent
+  behavior--Modification of habits possible in lower animals--Some
+  lower vertebrates profit by experience--Rational behavior--
+  Conceptual thought probably an outgrowth of simpler psychic
+  states--The capacity for alternative action in higher animals--The
+  elemental units of the nervous system are the same in lower and
+  higher animals--Neuron theory--Establishment of pathways through
+  the nervous system--Characteristic arrangements of nerve cells
+  subject to inheritance--Different parts of the cortex yield
+  different reactions--Skill acquired in one branch of learning
+  probably not transferred to another branch--Preponderance of
+  cortex in highest animals--Special fiber tracts in the spinal cord
+  of man and higher apes--Great complexity in associations and more
+  neurons in the brain of man--The nervous system in the main
+  already staged at the time of birth--Many pathways of conduction
+  not yet established--The extent of the modifiable zone unknown--
+  Various possibilities of reaction in the child--Probable origin of
+  altruistic human conduct--Training in motive necessary--Actual
+  practise in carrying out projects important--Interest and
+  difficulty both essential--The realization of certain
+  possibilities of the germ rather than others is subject to
+  control--We must afford the opportunity and provide the proper
+  stimuli for the development of good traits--Moral responsibility.
+
+  VIII MENTAL AND NERVOUS DEFECTS                                      228
+
+  Prevalence of insanity--Imperfect adjustments of the brain
+  mechanism inheritable--Many mental defectives married--
+  Disproportionate increase in number of mental defectives--Protests
+  voiced by alienists--Examples of hereditary feeble-mindedness--
+  Difficult to secure accurate data--Feeble-mindedness and insanity
+  not the same--Many types of insanity--Not all insanities of the
+  same eugenical significance--Difficulties of getting genealogies
+  of specific forms of insanity--Certain forms of insanity seem to
+  behave as Mendelian recessives--Grades of feeble-mindedness--About
+  two-thirds of feeble-mindedness inherited--Some results of
+  non-restraint of the feeble-minded--Not all cases of mental
+  deficiency inherited--Epileptics--Feeble-mindedness probably a
+  recessive--Many apparently normal people are carriers of
+  neuropathic defects--Tests for mental deficiency--The backward
+  child in school--The exceptionally able child--Cost of caring for
+  our mentally disordered--Importance of rigid segregation of the
+  feeble-minded--Importance of early diagnosis of insanity--Opinion
+  of competent psychiatrists essential--Some insanities not
+  hereditary--Importance of heredity in insanity not appreciated.
+
+  IX CRIME AND DELINQUENCY                                             263
+
+  Heredity and environment in this field--Feeble-mindedness often a
+  factor--Many delinquent girls mentally deficient--Institutional
+  figures misleading--Many prisoners mentally subnormal--Inhibitions
+  necessary to social welfare--The high-grade moron a difficult
+  problem--Degenerate strains--Intensification of defects by
+  inbreeding--Vicious surroundings not a sufficient explanation in
+  degenerate stocks--Not all delinquents defectives--No special
+  inheritable crime-factor--What is a born criminal?--Epileptic
+  criminal especially dangerous--The mental disorders most
+  frequently associated with crime--Bearing of immigration on crime
+  and delinquency--Sexual vice--School instruction in sex-hygiene--
+  Mere knowledge not the crux of the sex problem--Early training in
+  self-restraint an important preventive of crime and delinquency--
+  Multiplication of delinquent defectives must be prevented.
+
+  X RACE BETTERMENT THROUGH HEREDITY                                   289
+
+  Questionable charity--Past protests--An increasing flood of
+  defectives--Natural elimination of defectives done away with--Why
+  not prevent our social maladies?--Eugenics defined--Improved
+  environment alone will not cure racial degeneracy--Heredity and
+  environment--Inter-racial marriage--Human conservation--Kindness
+  in the long run--The problem has two phases--Constructive eugenics
+  must be based on education--Inferior increasing more rapidly than
+  superior stocks--An unselected population may contain much
+  valuable material--The lack of criteria for judging fitness--The
+  college graduate--Native ability, independence and energy
+  eugenically desirable--Four children to each marriage required to
+  maintain a stock--Factors contributing to low birth-rate in
+  desirable strains--The educated public must be made to realize the
+  situation--Utilization of family pride as a basis for constructive
+  eugenics--The tendency for like to marry like--Public opinion as
+  an incentive to action--Choosing a marriage mate means choosing a
+  parent--The best eugenic marriage also a love match--The
+  elimination of the grossly unfit urgent--Suggested remedies--
+  Inefficacy of laws which forbid marriage of mental defectives--
+  Systems of mating impracticable in the main--Corrective mating
+  presupposes knowledge of eugenics--Segregation has many
+  advocates--Sterilization as a eugenic measure--To what conditions
+  applicable--In insanity--In feeble-mindedness--In cases of
+  epilepsy--Sterilization laws--Social dangers in vasectomy--Our
+  present knowledge insufficient--Sterilization laws on trial--An
+  educated public sentiment the most valuable eugenic agent--The
+  question of personal liberty--Education of women in eugenics
+  needed--Much yet to be done--A working program--Which shall it be?
+
+  GLOSSARY                                                             343
+
+  REFERENCES FOR FURTHER READING AND STUDY                             355
+
+  INDEX                                                                361
+
+
+
+
+BEING WELL-BORN
+
+
+
+
+CHAPTER I
+
+HEREDITY
+
+
+It is a commonplace fact that offspring tend to resemble their parents. So
+commonplace, indeed, that few stop to wonder at it. No one misunderstands
+us when we say that such and such a young man is "a chip off the old
+block," for that is simply an emphatic way of stating that he resembles
+one or the other of his parents. The same is true of such familiar
+expressions as "what's bred in the bone," "blood will tell," and kindred
+catch phrases. All are but recognitions of the same common fact that
+offspring exhibit various characteristics similar to those of their
+progenitors.
+
+=Blood Heritage.--=To this phenomenon of resemblance in successive
+generations based on ancestry the term heredity is applied. In man, for
+instance, there is a marked tendency toward the reappearance in offspring
+of structures, habits, features, and even personal mannerisms, minute
+physical defects, and intimate mental peculiarities like those possessed
+by their parents or more remote forebears. These personal characteristics
+based on descent from a common source are what we may call the blood
+heritage of the child to discriminate it from a wholly different kind of
+inheritance, namely, the passing on from one generation to the next of
+such material things as personal property or real estate.
+
+=Kind Determined by Origin.--=It is inheritance in the sense of community
+of origin that determines whether a given living creature shall be man,
+beast, bird, fish, or what not. A given individual is human because his
+ancestors were human. In addition to this stock supply of human qualities
+he has certain well-marked features which we recognize as characteristics
+of race. That is, if he is of Anglo-Saxon or Italian or Mongolian
+parentage, naturally his various qualities will be Anglo-Saxon, Italian,
+or Mongolian. Still further, he has many distinctive features of mind and
+body that we recognize as family traits and lastly, his personal
+characteristics such as designate him to us as Tom, Harry, or James must
+be added. The latter would include such minutiae as size and shape of ears,
+nose or hands; complexion; perhaps even certain defects; voice; color of
+eyes; and a thousand other particulars. Although we designate these
+manifold items as individual, they are in reality largely more or less
+duplicates of similar features that occur in one or the other of his
+progenitors, features which he would not have in their existing form but
+for the hereditary relation between him and them.
+
+  "O Damsel Dorothy! Dorothy Q.!
+  Strange is the gift that I owe to you;
+
+    *       *       *       *       *
+
+  What if a hundred years ago
+  Those close-shut lips had answered 'No,'
+
+    *       *       *       *       *
+
+  Should I be I, or would it be
+  One-tenth another, to nine-tenths me?"
+
+  "Soft is the breath of a maiden's yes;
+  Not the light gossamer stirs with less;
+  But never a cable that holds so fast
+  Through all the battles of wave and blast,
+  And never an echo of speech or song
+  That lives in the babbling air so long!
+  There were tones in the voice that whispered then
+  You may hear to-day in a hundred men."
+
+When life steps into the world of matter there comes with it a sort of
+physical immortality, so to speak; not of the individual, it is true, but
+of the race. But the important thing to note is that the race is made up,
+not of a succession of wholly unrelated forms, but a continuation of the
+same kind of living organisms, and this sameness is due to the actual
+physical descent of each new individual from a predecessor. In other
+words, any living organism is the kind of organism it is in virtue of its
+hereditary relation to its ancestors.
+
+It is part of the biologist's task to seek a material basis, a continuity
+of actual substance, for this continuity of life and form between an
+organism and its offspring. Moreover, inasmuch as the offspring is never
+precisely similar to its progenitors he must determine also what qualities
+are susceptible of transmission and in what measure.
+
+=Ancestry a Network.--=From the fact that each child has all of the
+ancestors of its mother as well as of its father, arises the great
+complications which are met with in determining the lineage of an
+individual. A person has two parents, four grandparents, eight great
+grandparents, and thus following out pedigree it is plain to be seen that
+through this process of doubling in each generation, in the course of a
+few centuries one's ancestry is apparently enormous. By actual
+computation, according to Professor D. S. Jordan, if we count thirty
+generations back to the Norman invasion of England in 1066, at this ratio
+of duplication, the child of to-day would have had at that time an
+ancestry of 8,598,094,592 persons. But we know that the total number of
+inhabitants in England during the time of William the Conqueror was but a
+small fraction of this enormous aggregate. This means that we shall have
+to modify our inference that a child has twice as many ancestors as its
+parents; a condition which at first sight seems evident, but which is not
+literally true. The fact is that the parents of the child, in all
+probability, have many ancestors in common--a state of affairs which is
+brought about through the intermarriage of relatives, and this is
+especially frequent among remoter descendants of common progenitors. Time
+after time in genealogy strains of blood have crossed and recrossed until
+it is not improbable that a man of to-day who is of English origin has the
+blood in his veins from every inhabitant of England who lived during the
+time of William the Conqueror and left fruitful descendants. Instead of
+conceiving of ancestry as an ever branching and widening tree-like system
+as it recedes into the past, it is more accurate, therefore, to regard it
+in the light of an elaborate meshwork. The "family tree" in reality
+becomes the family net.
+
+=Ancestry in Royalty.--=The pedigrees of royal families have proved to be
+of much importance in the study of human inheritance, not that royal
+traits are any more heritable than any other, but simply because the
+records have been carefully kept so that they are the most comprehensive
+and easily followed pedigrees available. The netlike weave of ancestry is
+particularly well exemplified in some of these families because of much
+close intermarriage. Their heritage typifies on an intensified scale the
+heritage of the mass of mankind. For example, if we go six generations
+back in the ancestry of Frederick the Great instead of the expected
+sixty-four individual ancestors we find only forty; or in a still more
+closely woven stock, in the Spanish royal line of Don Carlos we find in
+six generations instead of sixty-four individual ancestors, only
+twenty-eight. While the present German emperor might have had four
+thousand ninety-six ancestors in the twelfth generation back, it is
+estimated that owing to intermarriage he probably had only five hundred
+thirty-three.
+
+=Offspring Derived from One Parent Only.--=So far in our reckoning of
+heredity we have counted elements from both father and mother, and the
+complications which arise from such a double ancestry are manifestly very
+perplexing ones. If we could do away with the elements of sex and find
+offspring that are derived from one parent only, it would seemingly
+simplify our problem very much for we should thus have a direct line of
+descent, free from intermingling. This, in fact, occurs to a greater or
+less extent among lower animals in a number of instances. There may be
+only female forms for a number of generations and the eggs which they
+produce develop directly into new individuals. Moreover, many of the
+simpler organisms have the power of dividing their bodies into two and
+thus giving rise to two new forms, each of which resembles the parent.
+This shows plainly that we may have inheritance without the appearance of
+any male ancestor at all, hence sex is not always a necessary factor in
+reproduction or heredity. The development of eggs asexually, that is,
+without uniting first with a male cognate, is termed _parthenogenesis_.
+The ordinary plant louse or aphid which is frequently found upon geraniums
+is a familiar example of an animal which reproduces largely in this way.
+During the summer only the females exist and they are so astonishingly
+fertile that one such aphid and her progeny, supposing none dies, will
+produce one hundred million in the course of five generations. In the last
+broods of the fall, males and females appear and fertile eggs are produced
+which lie dormant through the winter to start the cycle of the next year.
+Again, the eggs of some kinds of animals which normally have to unite with
+a male germ before they develop, can be made to develop by merely treating
+them with chemical solutions. The difference between an offspring derived
+in such a manner, and one which has developed from an egg fertilized by
+the male is that it is made up of characteristics from only one source,
+the maternal.
+
+=Dual Ancestry an Aid in Studying Heredity.--=Although we have the factors
+of heredity in a more simplified form in the case of asexual
+transmission, as a matter of fact most of our insight into the problems
+of heredity has been attained from a study of sexually reproducing forms,
+because the very existence of two sets of more or less parallel features
+offers a kind of checking up system by which we can follow a given
+characteristic.
+
+=Reversion.--=Occasionally, however, plants and animals do not develop the
+complete individuality we might expect, but stop short at or re-attain
+some ancestral stage along the line of descent, and thus come to resemble
+some progenitor perhaps many generations back of their own time. Thus it
+is well known that as regards one or more characteristics a child may
+resemble a grandparent or often some remote ancestor much more closely
+than it does its immediate parent. The reappearance of such ancestral
+traits the student of heredity designates as _Reversion_ or _Atavism_.
+
+Reversion may occur apparently in any class of plants or animals. It is
+especially pronounced among domesticated forms, which through man's
+selection have been produced under more or less artificial conditions. For
+example, among fancy breeds of pigeons, there may be an occasional return
+to the old slaty blue color of the ancestral rock-pigeon, with two dark
+cross-bars on the wings, from which all modern breeds have been derived.
+This is almost sure to happen if the fancy varieties are inter-crossed for
+two or three generations. Another example of reversion frequently cited is
+the occasional reappearance in domestic poultry of the reddish or brownish
+color pattern of the ancestral jungle-fowl to which, among modern forms,
+the Indian game seems most nearly related in color. Still another example
+is the cross-bars or stripes occasionally to be seen on the forelegs of
+colts, particularly mules, reminiscent of the extinct wild progenitors
+which were supposedly striped.
+
+Fig. 1, p. 9, is a picture of a hybrid between the common fowl and the
+guinea-fowl. The chevron-like markings on certain feathers show a
+reversion to a type of color pattern that is prevalent among both the
+primitive pheasants (the domestic chicken is a pheasant) and the primitive
+guinea-fowls. Although the common spotted guinea-fowl may be crossed with
+a black chicken which shows no trace of barring, nevertheless the hybrid
+offspring are likely to bear a chevron-like pattern such as that shown in
+the picture.
+
+There has been much quibbling over the relative meanings of reversion and
+atavism. The general idea, whichever term we use, is that there is a
+"throwing back" in a noticeable degree through inheritance to some
+ancestral condition beyond the immediate parents. A few recent authors
+have taken the term atavism in a restricted sense and use it to signify
+specifically those not uncommon cases in which a particular character of
+an offspring resembles the corresponding character of a grandparent
+instead of a parent. Such, for example, as the blue eye-color of a child
+with brown-eyed parents, each of whom in turn has had a blue-eyed parent.
+The tendency of other authors is to abandon the term entirely because of
+the diversity of meaning that has been attached to it in the past.
+
+
+[Illustration: FIG. 1
+
+Hybrid between the guinea-fowl and the common fowl, showing in many
+feathers reversion to a primitive chevron-like barring.]
+
+
+Certain classes of so-called reversions, such as the case of the eye-color
+just cited, are readily explicable on Mendelian principles as we shall see
+in a later chapter, but probably not all kinds of phenomena described as
+reversion can be so explained. For example, some seem to be cases of
+suppressed development. The word reversion, indeed, must be looked on as
+a convenient descriptive term rather than as the name of a single specific
+condition.
+
+=Telegony.--=There is yet a wide-spread belief in the supposed influence
+of an earlier sire on offspring born by the same mother to a later and
+different sire. This alleged phenomenon is termed _telegony_. For example,
+many dog-breeders assert that if a thoroughbred bitch has ever had pups by
+a mongrel father, her later offspring, although sired by a thoroughbred,
+will show taints of the former mongrel mating. In such cases the female is
+believed to be ruined for breeding purposes. Other supposed instances of
+such influences have been cited among horses, cattle, sheep, pigs, cats,
+birds, pets of various kinds and even men. The historic case most
+frequently quoted is that of Lord Morton's mare which bore a hybrid colt
+when bred to a quagga, a striped zebra-like animal now extinct. In later
+years the same mare bore two colts, sired by a black Arabian horse. Both
+colts showed stripes on the neck and other parts of the body, particularly
+on the legs. It was inferred that this striping was a sort of after effect
+of the earlier breeding with the quagga. In recent times, however,
+Professor Ewart has repeated the experiment a number of times with
+different mares using a Burchell zebra as the test sire. Although his
+experiments have been devised so as to conduce in every way possible to
+telegony his results have been negative. Moreover, it has been pointed out
+that the stripes on the legs of the two foals alleged to show telegony
+could not have been derived from the quagga sire for, unlike zebras,
+quaggas did not have their legs striped. Furthermore it is known that the
+occurrence of dark brown stripes on the neck, withers and legs of ordinary
+colts is not uncommon, some cases of which have exhibited more zebra-like
+markings than those of the colts from Lord Morton's mare. It seems much
+more probable, therefore, that the alleged instances are merely cases of
+ordinary reversion to the striped ancestral color pattern which probably
+characterized the wild progenitors of the domesticated horse.
+
+Various experiments on guinea-pigs, horses, mice and other forms,
+especially devised to test out this alleged after-influence of an earlier
+sire, have all proved negative and the general belief of the biologist
+to-day is that telegony is a myth.
+
+=Prenatal Influences Apart from Heredity.--=In discussing the problems of
+heredity it is necessary to consider also the possibilities of external
+influences apart from lineage which may affect offspring through either
+parent. Although modifications derived directly by the parent, and
+prenatal influences in general, are of extremely doubtful value as of
+permanent inheritable significance, nevertheless they must be reckoned
+with in any inventory of a child's endowment at birth. Impaired vitality
+on the part of the mother, bad nutrition and physical vicissitudes of
+various kinds all enter as factors in the birthright of the child, who,
+moreover, may bear in its veins slumbering poisons from some progenitor
+who has handed on blood taints not properly attributable to heredity. Of
+such importance is this kind of influence to the welfare of the immediate
+child that it will be necessary to discuss it in considerable detail in a
+later chapter.
+
+=Parent Body and Germ Not Identical.--=Inasmuch as each new individual
+appears to arise from material derived from its parent, taking the
+evidence at its face value one might suppose that any peculiarity of
+organization called forth in the living substance of the parent would
+naturally be repeated in the offspring, but a closer study of the
+developing organism from its first inception to maturity shows this to be
+probably a wrong conclusion. The parent-body and the reproductive
+substance contained in that body are by no means identical. It becomes an
+important question to decide, in fact, how much effect, if any, either
+permanent or temporary, the parent-body really has on the germ.
+
+A given fertile germ (Fig. 2, p. 13) gives rise by a succession of
+divisions to a body which we call the individual, but such a germ also
+gives rise to a series of new germ-cells which reside in that individual,
+and it is these germ-cells, not something derived from the body, that pass
+on the determiners of distinguishing features or qualities from generation
+to generation. It is only by grasping the significance of this fact that
+we can understand how in certain cases a totally different set of
+characters may appear in an offspring than those manifested in either
+parent.
+
+=An Hereditary Character Defined.--=By a _character_, in discussions in
+heredity, is meant simply a trait, feature or other characteristic of an
+organism. Where we can pick out a single definable characteristic which
+acts as a unit in heredity, for greater accuracy we term it a
+_unit-character_. Many traits are known to be inherited on a unit basis or
+are capable of being analyzed into factors which are so inherited. These
+unit-characters are in large measure inherited independently of one
+another apparently, although cases of characters inherited as a unit along
+with other characters are known.
+
+=Hereditary Mingling a Mosaic Rather Than a Blend.--=The independence of
+unit-characters in inheritance leads us to the important conclusion that
+the mingling of two lines of ancestry into a new individual is in no sense
+bringing them into the "melting pot," as it has been picturesquely
+expressed, but it is rather to be regarded as the mingling of two mosaics,
+each particle of which retains its own individuality, and which, even if
+overshadowed in a given generation, may nevertheless manifest its
+qualities undimmed in later generations when conditions favorable to its
+expression transpire.
+
+
+[Illustration: FIG. 2
+
+Diagram illustrating germinal continuity. Through a series of divisions a
+germ-cell gives rise to a body or a soma and to new germ-cells. The
+latter, not the body, give rise in turn to the next generation.]
+
+
+=Determiners of Characters, Not Characters Themselves, Transmitted.--=The
+fact should be thoroughly understood that the actual thing which is
+transmitted by means of the germ in inheritance is not the character
+itself, but something which will _determine_ the character in the
+offspring. It is important to remember this, for often these
+_determiners_, as they are called, may lie unexpressed for one or more
+generations and may become manifest only in later descendants. The truth
+of the matter is, the child does not inherit its characters from
+corresponding characters in the parent-body, but parent and child are
+alike because they are both products of the same line of germ-plasm, both
+are chips from the same old block.
+
+
+METHODS OF STUDYING HEREDITY
+
+Before entering into details it will be well to get some idea of the
+methods which are commonly employed in arriving at conclusions in the
+field of heredity. Some of these are extremely complex and all that we can
+do in an elementary presentation is to get a glimpse of the procedures.
+
+=Our Knowledge of Heredity Derived Along Three Lines.--=Our modern
+conceptions of heredity have been derived mainly from three distinct lines
+of investigation: First, from the study of embryology, in which the
+biologist concerns himself with the genesis of the various parts of the
+individual, and the mechanism of the germs which convey the actual
+materials from which these parts spring; second, through experimental
+breeding of plants and animals to compare particular traits or features in
+successive generations; and third, through the statistical treatment of
+observations or measurements of a large number of parents and their
+offspring with reference to a given characteristic in order to determine
+the average extent of resemblance between parents and children in that
+particular respect.
+
+=The Method of Experimental Breeding.--=A tremendous impetus was given to
+the method of experimental breeding when it was realized that we can
+itemize many of the parts or traits of an organism into entities which are
+inherited independently one of another. Such traits, or as we have already
+termed them, unit-characters, may be not only independently heritable but
+independently variable as well. The experimental method seeks to isolate
+and trace through successive generations the separate factors which
+determine the individual unit-characters of the organism. In this attempt
+cross-breeding is resorted to. Forms which differ in one or more respects
+are mated and the progeny studied. Next these offspring are mated with
+others of their own kind or mated back with the respective parent types.
+In this way the behavior of a particular character may often be followed
+and the germinal constitutions of the individuals concerned can be
+formulated with reference to it. Inasmuch as we shall give much
+consideration to this method in the chapter on Mendelism we need not
+consider it further here.
+
+=The Statistical Method.--=The statistical method seeks to obtain large
+bodies of facts and to deal with evidence as it appears through
+mathematical analysis of these facts. The attempt of its followers is to
+treat quantitatively all biological processes with which it is concerned.
+Historically Sir Francis Galton was the first to make any considerable
+application of statistical methods to the problems of heredity and
+variation. In his attempts to determine the extent of resemblance between
+relatives of different degree as regards bodily, mental and temperamental
+traits, he devised new methods of statistical analysis which constitute
+the basis of modern statistical biology, or _biometry_ as it is termed by
+its votaries. Professor Karl Pearson in particular has extended and
+perfected the mathematical methods of this field and stands to-day as
+perhaps its most representative exponent. The system is in the main based
+on the calculus of probability. The methods often are highly specialized,
+requiring the use of higher mathematics, and are therefore only at the
+command of specially trained workers.
+
+Just as insurance companies can tell us the probable length of human life
+in a given social group, since although uncertain in any particular case,
+it is reducible in mass to a predictable constant, so the biometrician
+with even greater precision because of his improved methods can often,
+when a large number of cases are concerned, give us the intensity of
+ancestral influence with reference to particular characters.
+
+For example, it is clear that by measuring a large number of adult human
+beings one can compute the average height or determine the height which
+will fit the greatest number. There will be some individuals below and
+some above it, but the greater the divergence from this standard height
+the fewer will be the individuals concerned.
+
+Galton compared the heights of 204 normal English parents and their 928
+adult offspring. In order to equalize the measurements of men and women he
+found he had to multiply each female height by 1.08. Then, to take both
+parents into account when comparing height of parents to that of children
+he added the height of the father to the proportionately augmented height
+of the mother and divided by two, thus securing the height of what he
+termed the "mid-parent." He found that the mid-parental heights of his
+subjects ranged from 64.5 to 72.5 inches, and that the general _mode_ was
+about 68.5 inches. It should be mentioned that the _mode_, in a given
+population, represents the group containing the largest number of
+individuals of one kind; it may or may not coincide with the average. The
+children of all mid-parents having a given height were measured next and
+tabulated with reference to these mid-parents. The results of Galton's
+measurements may be expressed simply as follows:
+
+  -----------------------------------------------------------------
+                                          |MODE|
+  ----------------------------------------|----|-------------------
+  Height of mid-parent|    |    |    |    |    |    |    |    |
+  in inches           |64.5|65.5|66.5|67.5|68.5|69.5|70.5|71.5|72.5
+                      |    |    |    |    |    |    |    |    |
+  Average height of   |    |    |    |    |    |    |    |    |
+  offspring           |65.8|66.7|67.2|67.6|68.3|68.9|69.5|69.9|72.2
+  -----------------------------------------------------------------
+
+=The Law of Regression.--=It is plain from this table that the offspring
+of short mid-parents tend to be under average or modal height though not
+so far below as their parents. Likewise children of tall parents tend to
+be tall but less tall than their parents. This fact illustrates what is
+known as Galton's _law of regression_; namely, that if parents in a given
+population diverge a certain amount from the mode of the population as a
+whole, their children, while tending to resemble them, will diverge less
+from this mode. It is clear that the extent of regression is an inverse
+measure of the intensity of inheritance from the immediate parents; if the
+deviation of the offspring from the general mode were nearly as great as
+that of their parents then the intensity of the inheritance must be high;
+if but slight--that is, if the offspring regressed nearly to the
+mode--then the intensity of the inheritance must be ranked as low. In the
+example in question it must be ranked as relatively high. Computations
+show that as regards stature the fraction two-thirds represents
+approximately the amount of resemblance between the two generations where
+both parents are considered.
+
+=Correlations Between Parents and Offspring.--=In modern researches the
+conception of mid-parent and mid-grandparent as utilized by Galton has
+been largely abandoned. It has been found more convenient as well as more
+accurate to keep the measurements of the two parents separate and to deal
+with correlations between fathers and sons, fathers and daughters, mothers
+and sons, mothers and daughters, brother and brother, etc. Professor
+Pearson and his pupils have found for a number of characters that the
+correlation between either parent and children, whether sons or daughters,
+is relatively close. The correlation between brother and brother, sister
+and sister, and brother and sister, usually ranges a little higher than
+the corresponding relation between parents and children.
+
+=The Biometrical Method, Statistical, Not Physiological.--=While biometry
+may in certain cases go far toward showing us the average intensity of
+the inheritance of certain characters it can not replace the method of
+the experimental breeder which deals with particular characters in
+individual pedigrees. It must be borne in mind that the biometrical method
+is a statistical and not a physiological one and that it is applicable
+only when large numbers of individuals are considered in mass. It is most
+valuable in cases where we are unable sharply to define single characters,
+due probably to the concurrent action of a number of independent causes,
+or where experiment is impossible so that we have to depend solely on
+numerical data gained by observation.
+
+=Mental Qualities Inheritable.--=Galton showed by this method long ago,
+and Pearson and his school have extended and more clearly established the
+work, that exceptional mental qualities tend to be inherited. While on the
+average the children of exceptional parents tend to be less exceptional
+than their parents, still they are far more likely to be exceptional than
+are the children of average parents. By this method Professor Pearson has
+shown that such mental and temperamental attributes as ability, vivacity,
+conscientiousness, temper, popularity, handwriting, etc., are as
+essentially determined as are physical features through the hereditary
+endowment.
+
+
+
+
+CHAPTER II
+
+THE BEARERS OF THE HERITAGE
+
+
+Before we can make any detailed analysis of the inheritance of characters
+we should have some general idea of the physical structure of animals and
+particularly some familiarity with the development of an individual from
+the egg, as well as some knowledge of the nature of the germ-cells.
+
+=The Cell the Unit of Structure.--=If we examine one of the higher
+animals, as, for example, the horse, the dog, or man, we find that it is
+made up of a large number of constituents, such as bones, muscles, nervous
+elements, blood and other tissues. Each kind of tissue is composed of a
+number of living units, ordinarily microscopic in size, which are known as
+cells. A careful examination of various cells reveals that although they
+may differ greatly in size, shape and minor details, they all alike
+possess certain well-marked characteristics. Each when reduced to its
+fundamental form is seen to consist of a small mass of living matter
+termed protoplasm in which may usually be distinguished two regions--the
+cell-body or _cytoplasm_, and the _nucleus_ (Fig. 3, p. 21). Any cell,
+whether it be of the brain, of the liver, or from any organ of an animal
+or plant, has this same fundamental structure. In addition, a limiting
+membrane or wall of some kind is generally present, although it is not a
+necessary constituent of all cells.
+
+
+[Illustration: FIG. 3
+
+Diagram of a cell showing various parts.]
+
+
+=Unicellular Organisms.--=While such a structure as a tree or a horse is
+composed of countless millions of cells, on the other hand numerous
+organisms, both plant and animal, exist which consist of only one cell.
+Yet this cell is just as characteristically a cell as are the components
+of a complex animal or plant. It has the necessary parts, the cell body
+and the nucleus. Moreover it exhibits all of the fundamental activities of
+life, though in a simplified form, that a complex higher organism does.
+
+=Importance of Cell-Theory.--=This discovery that every living thing is a
+single cell or an aggregation of cooperating cells and cell-products is
+one of our most important biological generalizations because it has
+brought such a wide range of phenomena under a common point of view. In
+the first place, the structure of both plants and animals is reducible to
+a common fundamental unit of organization. Moreover, both physiological
+and pathological phenomena are more readily understood since we recognize
+that the functions of the body in health or disease are in large measure
+the result of the activities of the individual cells of the functioning
+part. Then again, the problems of embryological development have become
+much more sharply defined since it could be shown that the egg is a single
+cell and that it is through a series of divisions of this cell and
+subsequent changes in the new cells thus formed that the new organism is
+built up. And lastly, the problem of hereditary transmission has been
+rendered more definite and approachable by the discovery that the male
+germ is likewise a single cell, that fertilization of the egg is therefore
+the union of two cells, and that in consequence the mechanism of
+inheritance must be stowed away somehow in these two cells.
+
+=Heredity in Unicellular Forms.--=In unicellular animals one can readily
+see how it is possible for an individual always to give rise to its own
+kind. One of the simplest of the single-celled animals is the _Ameba_
+(Fig. 4, p. 24).
+
+The ameba eats and grows as do other animals. Sooner or later it reaches a
+size beyond which it can not increase advantageously, yet it is
+continuously taking in new food material which stimulates it to further
+growth. Here then is a problem. The ameba solves this difficulty by
+dividing to form two amebae. Such a division is illustrated in Fig. 4, p.
+24. First the nucleus divides, then the cell-body. When the two new amebae
+separate completely each renews the occupation of eating and growing. But
+what has become of the parent? Here, where once existed a large adult
+ameba are two young amebae. The parent individual as such has disappeared,
+yet there has been no death, for we have simply two bits of living jelly
+in place of one. They will in turn repeat the same process, so will their
+offspring, and thus, barring accident, this growth and reproduction, or
+overgrowth as we may regard it, may go on forever, as far as we know. Here
+the problem of heredity, or the resemblance of offspring to parent, is not
+a very complicated one. The substance of the cell-body and cell-nucleus
+divides into two similar halves, so that each descendant has the substance
+of the parent in its own body, only it has but half as much. It differs
+from the parent, not in quality or kind, but in size.
+
+
+[Illustration: FIG. 4
+
+Six successive stages in the division of _Ameba polypodia_ (after
+Schulze). The nucleus is seen as a dark spot in the interior.]
+
+
+=Reproduction and Heredity in Colonial Protozoa.--=There are enormous
+numbers of these single-celled animals existing in all parts of the world.
+Some are simple like the ameba, others are very complex in structure.
+Many, after division, move apart and pursue wholly independent courses of
+existence. On the other hand we find a modification appearing in some
+which is of the greatest importance. After division instead of moving
+apart the two cells may remain side by side and divide further to form
+two more, these in turn may divide and thus the process goes on until
+there is formed what is known as a colony. Each cell of such a colony
+resembles the original ancestral cell because each is a part of the actual
+substance of that cell. As in the ameba, the first two cells are the
+ancestral cell done up in two separate packets, and thus finally the full
+quota of cells must be so many separate packets of the same kind of
+material. Inasmuch as each is but a repetition of its original ancestor,
+it can, and at times does, produce a colony of the same kind as that
+ancestor produced.
+
+=Conjugation.--=At longer or shorter intervals, however, we find that two
+individuals, on the disruption of the old colony, instead of continuing
+the routine of establishing new colonies through a series of cell
+divisions, very radically alter their behavior. They unite and fuse into a
+single larger individual. This process is called _conjugation_. We find it
+occurring even in some species of ameba. The conjugating cells in some
+colonies are alike in size and appearance, in others different.
+
+=Specialization of Sex-Cells.--=A beautiful sphere-shaped colony known as
+_Volvox_ is to be found occasionally in roadside pools. Depending on the
+species of _Volvox_ to which it belongs, the colony may be made up of from
+a few hundred to several thousand individuals arranged in a single layer
+about the fluid-filled center of the sphere and bound together by a clear
+jelly-like inter-cellular substance. Each individual cell also connects
+with its neighbors by means of thin threads of living matter. One of the
+largest species is _Volvox globator_, one edge of which is represented in
+Fig. 5, p. 27. Mutual pressure of the cells gives them a polygonal shape
+when viewed from the surface. Each cell, with a few exceptions to be noted
+immediately, bears two long flagella, whip-like structures which project
+out into the water. The lashing of these flagella gives the ball a rotary
+motion and thus it moves about. When the colony has reached its adult
+condition and is ready to reproduce itself, certain cells without flagella
+and somewhat larger than the ordinary cells become more rounded in outline
+and increase considerably in size through the acquisition of food
+materials. They are then known as egg cells or ova. Each ovum finally
+enters on a series of cell-divisions forming a mass of smaller and smaller
+cells which gradually assumes the form of a hollow sphere like the parent
+colony. The young colonies thus formed drop into the interior of the
+parent colony to escape later to the outside as independent swimming
+organisms when the old colony dies and disintegrates.
+
+=The Fertilized Ovum Termed a Zygote.--=After a number of generations of
+such asexual reproduction, sexual reproduction occurs. The ova arise as
+usual. Certain members of the colony, on the other hand, go to the other
+extreme and divide up into bundles of from sixty-four to one hundred
+twenty-eight minute slender cells, each provided with flagella for
+locomotion. When mature these small flagellate cells, now known as
+_spermatozoa_, escape into the interior of the parent colony and swim
+about actively. Ultimately each ovum is penetrated by a spermatozoon, the
+two cells fuse completely and thus form the single _fertilized ovum_ or
+_zygote_. The body-cells of the mother colony finally disintegrate. After
+a period of rest each zygote, through a series of cell-divisions, develops
+into an adult Volvox. In some species of Volvox a still further advance is
+seen, in that instead of both kinds of gametes being produced in the same
+colony, the ova may be produced by one colony and the spermatozoa by
+another. Here, then, we have the foreshadowings of two sexes as separate
+individuals, a phenomenon of universal occurrence among the highest forms
+of animal life.
+
+
+[Illustration: FIG. 5
+
+_Volvox globator_ (from Hegner after Oltmanns). Half of a sexually
+reproducing colony: _o_, eggs; _s_, spermatozoa.]
+
+
+=Advancement Seen in the Volvox Colony.--=In the Volvox colony there is a
+distinct advance over the conditions met with in various lower protozoan
+colonies in that only certain individuals of the colony take part in the
+process of reproduction and these individuals are of two distinct types;
+one is a larger, food-laden cell or egg and the other a small, active,
+fertilizing cell. The motile forms are produced in much greater numbers
+than the eggs, plainly because they have to seek the egg and many will
+doubtless perish before this can be accomplished. This disparity in number
+is only a means of insuring fertilization of the egg. The remaining cells
+of the body carry on the ordinary activities of the colony such as
+locomotion and nutrition and have ceased to take any part in the
+production of new colonies.
+
+=Natural Death Appears With the Establishment of a Body Distinct from the
+Germ.--=Volvox is an organism of unusual interest because in it we see a
+prophecy of what is to come. Although still regarded as a colony of
+single-celled individuals, it represents in reality a transition between
+the whole group of unicellular animals termed protozoa and the many celled
+animals characterized by the possession of distinct tissues, known as
+_Metazoa_. Moreover, it shows an interesting stage in the establishment of
+a body or _soma_ distinct from special reproductive cells which have taken
+on the function of reproducing the colony. In such colonial forms natural
+death is found appearing for the first time, the reproductive cells alone
+continuing to perpetuate the species. Then again Volvox represents an
+important step in the establishment of sex in the animal kingdom for in
+its sexual reproduction the conjugating cells known as _gametes_ are no
+longer alike in appearance but have become differentiated into definite
+ova and spermatozoa.
+
+In Volvox as in the other organisms which we have studied we find that all
+of the cells including the germ-cells are produced by the repeated
+division of a parent cell, and consequently each must contain the
+characteristic living substance of that parent. Many other forms might be
+cited to illustrate reproduction in single-celled animals, whether free or
+in colonies, but all such cases would be practically but repetitions or
+modifications of those we have already examined.
+
+=Specialization in Higher Organisms.--=If we pass on to the higher animals
+and plants which are not single cells or colonies of similar cells but
+organisms made up of many different kinds of cells, we find a pronounced
+extension of the phenomenon met with in Volvox. Instead of each cell
+executing independently all of the life relations, certain ones are set
+apart for the performance of certain functions to the exclusion of other
+functions which are carried on by other members of the aggregation. Thus
+the organism as a whole has all the life relations carried on, but, as it
+were, by specialists.
+
+=Sexual Phenomena in Higher Forms.--=In the reproduction of multicellular
+organisms, one sees likewise but a continuation of the phenomena exhibited
+in Volvox. Ordinarily, each new form is produced by the successive
+divisions of a single germ-cell which in the vast majority of cases has
+conjugated with another germ-cell. In the development of the egg, as the
+divisions proceed, groups of cells become modified for their particular
+work until the entire organism is completed. During development certain
+cells are set apart for reproduction of the form just as they were in
+Volvox. These two kinds of reproductive cells in multicellular organisms
+are derived ordinarily from two separate individuals known as male and
+female, though there are some exceptions. The main difference between
+these cells which will have to unite to form a single fertile germ-cell,
+is that they have specialized in different directions; one is small and
+active, the other large, food-laden and passive. But with two such
+germ-cells coming as they do from two individuals, one the male, the other
+the female, it is obvious that the actual living substance of which each
+germ is composed will be distinctive of its own parental line and that
+when the germs unite these distinctive factors commingle, hence the
+complications of double ancestry arise.
+
+=Structure of the Cell.--=Before we can understand certain necessary
+details of the physical mechanism of inheritance we must inquire a little
+further into the finer structure of the cell and into the nature of cell
+division. A typical cell, as it would appear after treatment with various
+stains which bring out the different parts more distinctly, is shown in
+Fig. 3, p. 21. Typical, not that any particular kind of living cell
+resembles it very closely in appearance, but because it shows in a
+diagrammatic way the essential parts of a cell. In the diagram, there are
+two well-marked regions; a central _nucleus_ and a peripheral cell-body or
+_cytoplasm_. Other structures are pictured but only a few of them need
+command our attention at present. At one side of the nucleus one observes
+a small dot or granule surrounded by a denser area of cytoplasm. This body
+is called the _centrosome_. The nucleus in this instance is bounded by a
+well-marked nuclear membrane and within it are several substances. What
+appear to be threads of a faintly staining material, the _linin_, traverse
+it in every direction and form an apparent network. The parts on which we
+wish particularly to rivet our attention are the densely stained
+substances scattered along or embedded in the strands of this network in
+irregular granules and patches. This substance is called _chromatin_. It
+takes its name from the fact that it shows great affinity for certain
+stains and becomes intensely colored by them. This deeply colored portion
+of the cell, the chromatin, is by most biologists regarded as of great
+importance from the standpoint of heredity. One or more larger masses of
+chromatin or chromatin-like material, known as _chromatin nucleoli_, are
+often present, and not infrequently a small spheroidal body, differing in
+its staining reactions from the chromatin-nucleolus and sometimes called
+the _true nucleolus_, exists.
+
+=Cell-Division.--=In the simplest type of cell-division the nucleus first
+constricts in the middle, and finally the two halves separate. This
+separation is followed by a similar constriction and final division of the
+entire cell-body, which results in the production of two new cells. This
+form of cell-division is known as _simple_ or _direct division_. Such a
+simple division, while found in higher animals, is less frequent and
+apparently much less significant than another type of division which
+involves profound changes and rearrangements of the nuclear contents. The
+latter is termed _mitotic_ or _indirect_ cell-division. Fig. 6, p. 33,
+illustrates some of the stages which are passed through in indirect
+cell-division. The centrosome which lies passively at the side of the
+nucleus in the typical cell (Fig. 6_a_, p. 33) awakens to activity,
+divides and the two components come to lie at the ends of a fibrous
+spindle. In the meantime, the interior of the nucleus is undergoing a
+transformation. The granules and patches of chromatin begin to flow
+together along the nuclear network and become more and more crowded until
+they take on the appearance of one or more long deeply-stained threads
+wound back and forth in a loose skein in the nucleus (Fig. 6_b_, p. 33).
+If we examine this thread closely, in some forms it may be seen to consist
+of a series of deeply-stained chromatin granules packed closely together
+intermingled with the substance of the original nuclear network.
+
+As the preparations for division go on the coil in the nucleus breaks up
+into a number of segments which are designated as _chromosomes_ (Fig.
+6_c_, p. 33). The nuclear membrane disappears. The chromosomes and the
+spindle-fibers ultimately become related in such a way that the
+chromosomes come to lie at the equator of the spindle as shown in Fig
+6_d_, p. 33. Each chromosome splits lengthwise to form two daughter
+chromosomes which then diverge to pass to the poles of the spindle (Figs.
+6_e_ and _f_, p. 33). Thus each end of the spindle comes ultimately to be
+occupied by a set of chromosomes. Moreover each set is a duplicate of the
+other, because the substance of any individual chromosome in one group has
+its counterpart in the other. In fact this whole complicated system of
+indirect division is regarded by most biologists as a mechanism for
+bringing about the precise halving of the chromosomes.
+
+
+[Illustration: FIG. 6
+
+Diagram showing representative stages in mitotic or indirect
+cell-division: _a_, resting cell with reticular nucleus and single
+centrosome; _b_, the two new centrosomes formed by division of the old one
+are separating and the nucleus is in the spireme stage; _c_, the nuclear
+wall has disappeared, the spireme has broken up into six separate
+chromosomes, and the spindle is forming between the two centrosomes; _d_,
+equatorial plate stage in which the chromosomes occupy the equator of the
+spindle; _e_, _f_, each chromosome splits lengthwise and the daughter
+chromosomes thus formed approach their respective poles; _g_,
+reconstruction of the new nuclei and division of the cell body; _h_,
+cell-division completed.]
+
+
+The chromosomes of each group at the poles finally fuse and two new
+nuclei, each similar to the original one, are constructed (Figs. 6_g_ and
+_h_, p. 33). In the meantime a division of the cell-body is in progress
+which, when completed, results in the formation of two complete new cells.
+
+As all living matter if given suitable food, can convert it into living
+matter of its own kind, there is no difficulty in conceiving how the new
+cell or the chromatin material finally attains to the same bulk that was
+characteristic of the parent cell. In the case of the chromatin, indeed,
+it seems that there is at times a precocious doubling of the ordinary
+amount of material before the actual division occurs.
+
+=Chromosomes Constant in Number and Appearance.--=With some minor
+exceptions, to be noted later, which increase rather than detract from the
+significance of the facts, the chromosomes are always the same in number
+and appearance in all individuals of a given species of plants or animals.
+That is, every species has a fixed number which regularly recurs in all of
+its cell-divisions. Thus the ordinary cells of the rat, when preparing to
+divide, each display sixteen chromosomes, the frog or the mouse,
+twenty-four, the lily twenty-four, and the maw-worm of the horse only
+four. The chromosomes of different kinds of animals or plants may differ
+very much in appearance. In some they are spherical, in others rod-like,
+filamentous or perhaps of other forms. In some organisms the chromosomes
+of the same nucleus may differ from one another in size, shape and
+proportions, but if such differences appear at one division they appear at
+others, thus showing that in such cases the differences are constant from
+one generation to the next.
+
+=Significance of the Chromosomes.--=The question naturally arises as to
+what is the significance of the chromosomes. Why is the accurate
+adjustment which we have noted for their division necessary? The very
+existence of an elaborate mechanism so admirably adapted to their precise
+halving, predisposes one toward the belief that the chromosomes have an
+important function which necessitates the retention of their individuality
+and their equal division. Many biologists accept this along with other
+evidence as indicating that in chromatin we have a substance which is not
+the same throughout, that different regions of the same chromosome have
+different physiological values.
+
+When the cell prepares for divisions, the granules, as we have seen,
+arrange themselves serially into a definite number of strands which we
+have termed chromosomes. Judging from all available evidence, the granules
+are self-propagating units; that is, they can grow and reproduce
+themselves. So that what really happens in mitosis in the splitting of the
+chromosomes is a precise halving of the series of individual granules of
+which each chromosome is constituted, or in other words each granule has
+reproduced itself. Thus each of the two daughter cells presumably gets a
+sample of every kind of chromosomal particle, hence, the two cells are
+qualitatively alike. To use a homely illustration we may picture the
+individual chromosomes to ourselves as so many separate trains of freight
+cars, each car of which is loaded with different merchandise. Now, if
+every one of the trains could split along its entire length and the
+resulting halves each grow into a train similar to the original, so that
+instead of one there would exist two identical trains, we should have a
+phenomenon analogous to that of a dividing chromosome.
+
+=Cleavage of the Egg.--=It is through a series of such divisions as these
+that the zygote or fertilized egg-cell builds up the tissues and organs of
+the new organism. The process is technically spoken of as _cleavage_.
+Cleavage generally begins very shortly after fertilization. The fertile
+egg-cell divides into two, the resulting cells divide again and thus the
+process continues, with an ever-increasing number of cells.
+
+=Chief Processes Operative in Building the Body.--=Although of much
+interest, space will not permit of a discussion in detail of the building
+up of the special organs and tissues of the body. It must suffice merely
+to mention the four chief processes which are operative. These are, (1)
+infoldings and outfoldings of the various cell complexes; (2)
+multiplication of the component cells; (3) special changes (_histological
+differentiation_) in groups of cells; and (4) occasionally resorption of
+certain areas of parts.
+
+=The Origin of the New Germ-Cells.--=On account of the unusual importance
+from the standpoint of inheritance, which attaches to the germ-cells, a
+final word must be said about their origin in the embryo. While the
+evidence is conflicting in some cases, in others it has been well
+established that the germ-cells are set apart very early from the cells
+which are to differentiate into the ordinary body tissues. Fig. 7_A_, p.
+38, shows a section through the eight-celled stage of _Miastor_, a fly, in
+which a single large, primordial germ-cell (_p. g. c._) has already been
+set apart at one end of the developing embryo. The nuclei of the rest of
+the embryo still lie in a continuous protoplasmic mass which has not yet
+divided up into separate cells. The densely stained nuclei at the opposite
+end of the section are the remnants of nurse-cells which originally
+nourished the egg. Fig. 7_B_, p. 38, is a longitudinal section through a
+later stage in the development of _Miastor_; the primitive germ-cells
+(ooeg) are plainly visible. Still other striking examples might be cited.
+Even in vertebrates the germ-cells may often be detected at a very early
+period.
+
+=Significance of the Early Setting Apart of the Germ-Cells.--=It is of
+great importance for the reader to grasp the significance of this early
+setting apart of the germ-cells because so much in our future discussion
+hinges on this fact. The truth of the statement made in a previous chapter
+that the body of an individual and the reproductive substance in that body
+are not identical now becomes obvious. For in such cases as those just
+cited one sees the germinal substance which is to carry on the race set
+aside at an early period in a given individual; it takes no part in the
+formation of that individual's body, but remains a slumbering mass of
+potentialities which must bide its time to awaken into expression in a
+subsequent generation. Thus an egg does not develop into a body which in
+turn makes new germ-cells, but body and germ-cells are established at the
+same time, the body harboring and nourishing the germ-cells, but not
+generating them (Fig. 2, p. 13). The same must be true also in many cases
+where the earliest history of the germ-cells can not be visibly followed,
+because in any event, in all higher animals, they appear long before the
+embryo is mature and must therefore be descendants of the original
+egg-cell and not of the functioning tissues of the mature individual. This
+need not necessarily mean that the germ-cells have remained wholly
+unmodified or that they continue uninfluenced by the conditions which
+prevail in the body, especially in the nutritive blood and lymph stream,
+although as a matter of fact most biologists are extremely skeptical as to
+the probability that influences from the body beyond such general
+indefinite effects as might result from under-nutrition or from poisons
+carried in the blood, modify the intrinsic nature of the germinal
+substances to any measurable extent.
+
+
+[Illustration: FIG. 7
+
+A--Germ-cell (_p. g. c._) set apart in the eight-celled stage of cleavage
+in _Miastor americana_ (after Hegner). The walls of the remaining seven
+somatic cells have not yet formed though the resting or the dividing (_M
+p_) nuclei may be seen; _c R_, chromatin fragments cast off from the
+somatic cells.
+
+B--Section lengthwise of a later embryo of _Miastor_; the primordial
+egg-cells (_ooeg__{3}) are conspicuous (after Hegner).]
+
+
+=Germinal Continuity.--=The germ-cells are collectively termed the
+_germinal protoplasm_ and it is obvious that as long as any race continues
+to exist, although successive individuals die, some germinal protoplasm is
+handed on from generation to generation without interruption. This is
+known as the theory of _germinal continuity_. When the organism is ready
+to reproduce its kind the germ-cells awaken to activity, usually
+undergoing a period of multiplication to form more germ-cells before
+finally passing through a process of what is known at _maturation_, which
+makes them ready for fertilization. The maturation process proper, which
+consists typically of two rapidly succeeding divisions, is preceded by a
+marked growth in size of the individual cells.
+
+=Individuality of Chromosomes.--=Before we can understand fully the
+significance of the changes which go on during maturation we shall have to
+know more about the conditions which prevail among the chromosomes of
+cells. As already noted each kind of animal or plant has its own
+characteristic number and types of chromosomes when these appear for
+division by mitosis. In many organisms the chromosomes are so nearly of
+one size as to make it difficult or impossible to be sure of the identity
+of each individual chromosome, but on the other hand, there are some
+organisms known in which the chromosomes of a single nucleus are not of
+the same size and form (Fig. 8, p. 41). These latter cases enable us to
+determine some very significant facts. Where such differences of shape and
+proportion occur they are constant in each succeeding division so that
+similar chromosomes may be identified each time. Moreover, in all ordinary
+mitotic divisions where the conditions are accurately known, these
+chromosomes of different types are found to be present as pairs of similar
+elements; that is, there are two of each form or size.
+
+=Pairs of Similar Chromosomes in the Nucleus Because One Chromosome Comes
+from Each Parent.--=When we recall that the original fertilized egg from
+which the individual develops is really formed by the union of two
+gametes, ovum and spermatozoon, and that each gamete, being a true cell,
+must carry its own set of chromosomes, the significance of the pairs of
+similar chromosomes becomes evident; one of each kind has probably been
+contributed by each gamete. This means that the zygote or fertile ovum
+contains double the number of chromosomes possessed by either gamete, and
+that, moreover, each tissue-cell of the new individual will contain this
+dual number. For, as we have seen, the number of chromosomes is, with
+possibly a few exceptions, constant in the tissue-cells and early
+germ-cells in successive generations of individuals. For this to be true
+it is obvious that in some way the nuclei of the conjugating gametes have
+come to contain only half the usual number. Technically the tissue-cells
+are said to contain the _diploid_ number of chromosomes, the gametes the
+reduced or _haploid_ number.
+
+
+[Illustration: FIG. 8
+
+A--Chromosomes of the mosquito (_Culex_) after Stevens.
+
+B--Chromosomes of the fruit-fly (_Drosophila_) after Metz.
+
+Both of these forms have an unusually small number of chromosomes.]
+
+
+=In Maturation the Number of Chromosomes Is Reduced by One-Half.--=This
+halving, or as it is known, _reduction_ in the number of chromosomes is
+the essential feature of the process of maturation. It is accomplished by
+a modification in the mitotic division in which instead of each chromosome
+splitting lengthwise, as in ordinary mitosis, the chromosomes unite in
+pairs (Fig. 9_b_, p. 42), a process known technically as _synapsis_, and
+then apparently one member of each pair passes entire into one new
+daughter cell, the other member going to the other daughter cell (Fig.
+9_c_, p. 42). In the pairing preliminary to this _reduction division_,
+leaving out of account certain special cases to be considered later,
+according to the best evidence at our command the union always takes place
+between two chromosomes which match each other in size and appearance.
+Since one of these is believed to be of maternal and the other of
+paternal origin, the ensuing division separates corresponding mates and
+insures that each gamete gets one of each kind of chromosome although it
+appears to be a matter of mere chance whether or not a given cell gets the
+paternal or the maternal representative of that kind.
+
+
+[Illustration: FIG. 9
+
+Diagram to illustrate spermatogenesis: _a_, showing the diploid number of
+chromosomes (six is arbitrarily chosen) as they occur in divisions of
+ordinary cells and spermatogonia; _b_, the pairing (synapsis) of
+corresponding mates in the primary spermatocyte preparatory to reduction;
+_c_, each secondary spermatocyte receives three, the haploid number of
+chromosomes; _d_, division of the secondary spermatocytes to form _e_,
+spermatids, which transform into _f_, spermatozoa.]
+
+
+=Maturation of the Sperm-Cell.--=In the maturation of the male gamete the
+germ-cell, now known as a _spermatogonium_, increases greatly in size to
+become a _primary spermatocyte_. In each primary spermatocyte the pairing
+of the chromosomes already alluded to occurs as indicated in Fig. 9_b_, p.
+42, where six is taken arbitrarily to indicate the ordinary or _diploid_
+number of chromosomes, and three the reduced or _haploid_ number. The
+division of the primary spermatocyte gives rise to two _secondary
+spermatocytes_ (_c_), the paired chromosomes separating in such a way that
+a member of each pair goes to each secondary spermatocyte. Each secondary
+spermatocyte (_d_) soon divides again into two _spermatids_ (_e_), but in
+this second division the chromosomes each split lengthwise as in an
+ordinary division so that there is no further reduction. In some forms the
+reduction division occurs in the secondary spermatocytes instead of the
+primary. Each spermatid transforms into a mature spermatozoon (_f_). The
+spermatozoa of most animals are of linear form, each with a head, a
+middle-piece and a long vibratile tail which is used for locomotion. The
+head consists for the most part of the transformed nucleus and is
+consequently the part which bears the chromosomes.
+
+=Maturation of the Egg-Cell.--=As regards the behavior of the chromosomes
+the maturation of the ovum parallels that of the sperm-cell. There are not
+so many primordial germ-cells formed and only one out of four of the
+ultimate cells becomes a functional egg. As in maturation of the
+sperm-cell there is a growth period in which _ooegonia_ enlarge to become
+_primary ooecytes_ (Fig. 10_b_, p. 45). In each primary ooecyte as in the
+primary spermatocyte the chromosomes pair and two rapidly succeeding
+divisions follow in one of which the typical numerical reduction in the
+chromosomes occurs. A peculiarity in the maturation of the ovum is that
+there is a very unequal division of the cytoplasm in cell division so that
+three of the resulting cells usually termed _polar bodies_ are very small
+and appear like minute buds on the side of the fourth or egg-cell proper.
+
+The scheme of this formation of the polar bodies is indicated in Fig. 10,
+p. 45. In Fig. 10_b_ the chromosomes are seen paired and ready for the
+first division; that is, for the formation of the first polar body. Figs.
+10_c_, _d_, p. 45, show the giving off of this body. Note that while only
+a small proportion of the cytoplasm passes into this tiny cell, its
+chromatin content is as great as that of the ovum. A second polar body
+(Figs. 10_e_, _f_, p. 45) is formed by the egg, but in this case each
+chromosome splits lengthwise, as in ordinary mitosis, and there is no
+further numerical reduction. In the meantime, typically, a third polar
+body is formed by division of the first. (Stages _e_, _f_, _g_.)
+
+=Parallel Between the Maturation of Sperm- and Egg-Cell.--=This rather
+complex procedure of the germ-cells will be rendered more intelligible
+through a careful study of Figs. 9 and 10, pp. 42 and 45, and Fig. 11, p.
+46, which indicates the parallel conditions in spermotogenesis and
+ooegenesis.
+
+
+[Illustration: FIG. 10
+
+Diagram to illustrate ooegenesis: _a_, showing the diploid number of
+chromosomes (six is arbitrarily chosen) as they occur in ordinary cells
+and ooegonia; _b_, the pairing of corresponding mates preparatory to
+reduction; _c_, _d_, reduction division, giving off of first polar body;
+_e_, egg preparing to give off second polar body, first polar body ready
+for division; _f_, _g_, second polar body given off, division of first
+polar body completed. The egg nucleus, now known as the female pronucleus,
+and each body contain the reduced or haploid number of chromosomes.]
+
+
+The view now generally held regarding the polar bodies is that they are
+really abortive eggs. They later disappear, taking no part in
+embryo-formation. It can readily be seen how such an unequal division is
+advantageous to the large cell, for it receives all of the rich store of
+food material that would be distributed among the four cells if all were
+of equal size. This increased amount of food is a favorable provision for
+the forthcoming offspring whose nourishment is thus more thoroughly
+insured.
+
+
+[Illustration: FIG. 11
+
+Diagram showing the parallel between maturation of the sperm-cell and
+maturation of the ovum.]
+
+
+On the other hand, all of the sperm-cells develop into complete active
+forms, which, as aforesaid, usually become very much elongated and develop
+a motile organ of some kind. In such cells an accumulation of food to any
+large extent would hinder rather than help them, because it would
+seriously interfere with their activity.
+
+=Fertilization.--=In fertilization (Fig. 12, p. 48) the spermatozoon
+penetrates the wall of the ovum and after undergoing considerable
+alteration its nucleus fuses with the nucleus of the egg. In some forms
+only the head (nucleus) and middle-piece enter, the tail being cut off by
+a so-called fertilization membrane which forms at the surface of the egg
+and effectually blocks the entrance of other spermatozoa. Thus normally
+only one spermatozoon unites with an egg. In some forms while several may
+enter the egg only one becomes functional. As soon as the nucleus of the
+spermatozoon, now known as the male _pronucleus_, reaches the interior of
+the egg, it enlarges and becomes similar in appearance to the female
+_pronucleus_. It swings around in such a way (Fig. 12_b_, p. 48) that the
+middle piece, now transformed into a centrosome, lies between it and the
+female pronucleus. The two pronuclei (_c_, _d_, _e_), each containing the
+reduced number of chromosomes, approach, the centrosome divides, the
+nuclear walls disappear, the typical division spindle forms, and the
+chromosomes of paternal and maternal origin respectively come to lie side
+by side at the equator of the spindle ready for the first division or
+cleavage (_f_, _g_). It will be noted that the individual chromosomes do
+not intermingle their substance at this time, but that each apparently
+retains its own individuality. There is considerable evidence which
+indicates that throughout life the chromosomes contributed by the male
+parent remain distinct from those of the female parent. Inasmuch as each
+germ-cell, after maturation, contains only half the characteristic number
+of chromosomes, the original number is restored in fertilization.
+
+
+[Illustration: FIG. 12
+
+Diagram to illustrate fertilization; [male], male pronucleus; [female],
+female pronucleus; observe that the chromosomes of maternal and paternal
+origin respectively do not fuse.]
+
+
+=Significance of the Behavior of the Chromosomes.--=The question confronts
+us as to what is the significance of this elaborate system which keeps the
+chromosomes of constant size, shape and number; which partitions them so
+accurately in ordinary cell-divisions; and which provides for a reduction
+of their numbers by half in the germ-cell while yet securing that each
+mature gamete gets one of each kind of chromosome. Most biologists look on
+these facts as indicating that the chromosomes are specifically concerned
+in inheritance.
+
+In the first place it is recognized that as regards the definable
+characters which separate individuals of the same species, offspring may
+inherit equally from either parent. And it is a very significant fact that
+while the ovum and spermatozoon are very unequal in size themselves, the
+chromosomes of the two germ-cells are of the same size and number. This
+parity in chromosomal contribution points clearly to the means by which an
+equal number of character-determiners might be conveyed from each parent.
+Moreover it is mainly the nucleus of the sperm-cell in some organisms
+which enters the egg, hence the determiners from the male line must exist
+wholly or largely somewhere in the nucleus. And the bulk of the nucleus in
+the spermatozoon consists of the chromosomes or their products.
+
+=A Single Set of Chromosomes Derived from One Parent Only Is Sufficient
+for the Production of a Complete Organism.--=That a single or haploid set
+of chromosomes as seen in the gametes is sufficient contribution of
+chromatin for the production of a complete organism is proved by the fact
+that the unfertilized eggs of various animals (many echinoderms, worms,
+mollusks, and even the frog) may be artificially stimulated to development
+without uniting at all with a spermatozoon. The resulting individual is
+normal in every respect except that instead of the usual diploid number it
+has only the single or haploid number of chromosomes. Its inheritance of
+course is wholly of maternal origin. The converse experiment in
+echinoderms in which a nucleus of male origin (that is, a spermatozoon)
+has been introduced into an egg from which the original nucleus has been
+removed shows that the single set of chromosomes carried by the male
+gamete is also sufficient to cooperate with the egg-cytoplasm in
+developing a complete individual.
+
+=The Duality of the Body and the Singleness of the Germ.--=Since every
+maternal chromosome in the ordinary cell has an equivalent mate derived
+from the male parent, it follows therefore, supposing the chromosomes do
+have the significance in inheritance attributed to them, that as regards
+the measurable inheritable differences between two individuals, the
+ordinary organism produced through the union of the two germ-cells is,
+potentially at least, dual in nature. On the other hand through the
+process of reduction the gametes are provided with only a single set of
+such representatives. This duality of the body and singleness of the
+mature germ is one of the most striking facts that come to light in
+embryology. How well the facts fit in with the behavior of certain
+hereditary characters will be seen later in our discussions of Mendelism.
+
+=The Cytoplasm Not Negligible in Inheritance.--=Just what part is played
+by the cytoplasm in inheritance is not clear, but it is probably by no
+means a negligible one. The cytoplasm of a given organism is just as
+distinctive of the species or of the individual of which it forms a part
+as are the chromosomes. It is well established that neither nucleus nor
+cytoplasm can fully function or even exist long without the other, and
+neither can alone produce the other. They undoubtedly must cooperate in
+building up the new individual, and the cytoplasm of the new individual is
+predominantly of maternal origin. It is obvious that all of the more
+fundamental characters which make up an organism, such, for instance, as
+make it an animal of a certain order or family, as a human being or a dog
+or a horse, are common to both parents, and there is no way of measuring
+how much of this fundamental constitution comes from either parent, since
+only closely related forms will interbreed. In some forms, moreover, the
+broader fundamental features of embryogeny are already established before
+the entrance of the spermatozoon. It is probable therefore that instead of
+asserting that the entire quota of characters which go to make up a
+complete individual are inherited from each parent equally, we are
+justified only in maintaining that this equality is restricted to those
+measurable differences which veneer or top off, as it were, the
+individual. We may infer that in the development of the new being the
+chromosomes of the egg together with those derived from the male work
+jointly on or with the other germinal contents which are mostly
+cytoplasmic materials of maternal origin.
+
+=The Chromosomes Possibly Responsible for the Distinctiveness of Given
+Characters.--=It seems probable that in the establishment of certain basic
+features of the organism the cooperation of the cytoplasm with chromatin
+of either maternal or paternal origin might accomplish the same end, but
+that certain distinctive touches are added or come cumulatively into
+expression through influences carried, predominantly at least, in the
+chromatin from one as against the other parent. These last distinctive
+characters of the plant or animal constitute the individual differences of
+such organisms. In this connection it is a significant fact that in young
+hybrids between two distinct species the early stages of development,
+especially as regards symmetry and regional specifications, are
+exclusively or predominantly maternal in character, but the male influence
+becomes more and more apparent as development progresses until the final
+degree of intermediacy is attained.
+
+From the evidence at hand this much seems sure, that the paternal and
+maternal chromosomes respectively carry substances, be they ferments,
+nutritive materials or what not, that are instrumental in giving the final
+parity of personal characters which we observe to be equally heritable
+from either line of ancestry. It is clear that most of the characters of
+an adult organism can not be merely the outcome of any unitary substance
+of the germ. Each is the product of many cooperating factors and for the
+final outcome any one cooperant is probably just as important in its way
+as any other. The individual characters which we juggle to and fro in our
+breeding experiments seem apexed, as it were, on more fundamental features
+of organic chemical constitution, polarity, regional differentiation, and
+physiological balance, but since such individual characters parallel so
+closely the visible segregations and associations which go on among the
+chromosomes of the germ-cells it would seem that they, at least, are
+represented in the chromosomes by distinctive cooperants which give the
+final touch of specificity to those hereditary characters which can be
+shifted about as units of inheritance.
+
+=Sex and Heredity.--=Whatever the origin of fertilization may have been in
+the world of life, or whatever its earliest significance, the important
+fact remains that to-day it is unquestionably of very great significance
+in relation to the phenomena of heredity. For in all higher animals, at
+least, offspring may possess some of the characteristics originally
+present in either of two lines of ancestry, and this commingling of such
+possessions is possible only through sexual reproduction. As has already
+been seen, in the pairing of chromosomes previous to reduction, the
+corresponding members of a pair always come together so that in the final
+segregation each gamete is sure to have one of each kind although whether
+a given chromosome of the haploid set is of maternal or paternal origin
+seems to be merely a matter of chance. Thus, for instance, if we
+arbitrarily represent the chromosomes of a given individual by _ABC_
+_abc_, and regard _A_, _B_ and _C_ as of paternal and _a_, _b_ and _c_ as
+of maternal origin, then in synapsis only _A_ and _a_ can pair together,
+_B_ and _b_ and _C_ and _c_, but each pair operates independently of the
+other so that in the ensuing reduction division either member of a pair
+may get into a cell with either member of the other pairs. That is, the
+line up for division at a given reduction might be any one of the
+following, ABC/abc ABc/abC Abc/aBC AbC/aBc. This would yield the following
+eight kinds of gametes, _ABC_, _abc_, _ABc_, _abC_, _Abc_, _aBC_, _AbC_,
+_aBc_, each bearing one of each kind of chromosome required to cover the
+entire field of characters necessary to a complete organism. And since
+each sex would be equally likely to have these eight types of gametes and
+any one of the eight in one individual might meet any one of the eight of
+the other, the possible number of combinations in the production of a new
+individual from such germ-cells would be 8x8, or 64. With the larger
+numbers of chromosomes which exist in most animals it is readily seen that
+the number of possible combinations becomes very great. Thus any
+individual of a species with twenty chromosomes--and many animals,
+including man, have more--would have ten pairs at the reduction period and
+could therefore form (2)^{10}, or 1,024 different gametes in each sex. And
+since any one of these in one sex would have an equal chance of meeting
+with any one in the opposite sex, the total number of possible different
+zygotes that might be produced would be (1,024)^{2}, or 1,048,576. Sex
+therefore, through recombinations of ancestral materials, undoubtedly
+means, among other things, the production of great diversity in
+offspring.
+
+
+DETERMINATION OF SEX
+
+=Many Theories.--=From earliest times the problem of sex determination has
+been one of keen interest, and needless to say hundreds of theories have
+been propounded to explain it. Geddes and Thomson say that Drelincourt
+recorded two hundred sixty-two so-called theories of sex production and
+remark that since his time the number has at least been doubled. The
+desirability of controlling sex has naturally appealed strongly to
+breeders of domesticated animals.
+
+A study of animals born in litters, or of twins, is enough in itself to
+make us skeptical of theories of sex-determination based on nutritional or
+external factors. In a litter of puppies, for example, there are usually
+both males and females, although in their prenatal existence they have all
+been subject to the same nutritional and environmental conditions.
+Likewise in ordinary human twins one may be a boy, the other a girl,
+whereas if the nutritional condition of the mother were the fact
+determining sex, both should be boys or both girls. However, there are
+twins known as _identical twins_ who are remarkably alike and who are
+always of the same sex. But there is reason to suppose that identical
+twins in reality come from the same zygote. Presumably in early
+embryogeny, probably at the two-celled stage of cleavage, the two
+blastomeres become separated and each gives rise to a complete individual
+instead of only the half of one it would have produced had the two
+blastomeres remained together. Such twins are monochorial; that is, they
+grow inside the same fetal membrane, whereas each ordinary twin has its
+own fetal membrane and has obviously originated from a separate ovum. It
+has been established experimentally in several kinds of animals that early
+cleavage blastomeres when isolated can each develop into a complete
+individual. In man, ordinary twins are no more alike than ordinary
+brothers and sisters, but identical twins are strikingly similar in
+structure, appearance, habits, tastes, and even susceptibility to various
+maladies. The fact that they are invariably of the same sex is a strong
+reason for believing that sex was already developed in the fertile ovum
+and consequently in the resulting blastomeres from that ovum.
+
+The young of the nine-banded armadillo in a given litter are invariably of
+the same sex and are closely similar in all features. Newman and Patterson
+have shown that all the members of a litter come from the same egg.
+Patterson has established the fact that cleavage of the egg takes place in
+the usual manner, but later separate centers of development appear in the
+early embryonic mass and give rise to the separate young individuals.
+
+Again in certain insects where one egg indirectly gives rise to a chain of
+embryos, or to a number of separate larvae, possibly as many as a thousand,
+all of the latter are of the same sex. Even in some plants researches have
+shown that sex is already determined at the beginning of development.
+Then, too, much evidence has come to light recently showing that
+sex-characters in certain cases behave as heritable characters and are
+independent of external conditions. Lastly there is visible and convincing
+evidence obtainable through microscopical observations that sex is
+determined by a mechanism in the germ-cells themselves. It is chiefly to
+these latter facts that I wish to direct attention for the present.
+
+=The Sex Chromosome.--=The evidence centers about a special chromosome or
+chromosome-group commonly designated as the _sex-chromosome_ or
+_X-element_, which has been found in various species of animals, including
+man. In the males of such animals this chromosome is present in addition
+to the regular number of pairs, thus giving rise to an _uneven_ instead of
+the conventional even number of chromosomes. This element remains
+undivided in one of the maturation divisions of the spermatocytes, in some
+forms in the first in others in the second, and passes entire to one pole
+of the spindle (Fig. 13, p. 58). This results in the production of two
+classes of cells, one containing the _X_-element and one not. The outcome
+is that two corresponding classes of spermatozoa are produced. The
+phenomena involved are diagrammatically represented in Fig. 13. It has
+been clearly demonstrated in several cases that eggs fertilized by
+spermatozoa which possess this _X_-element, always become females, those
+fertilized by spermatozoa which do not possess it always develop into
+males.
+
+
+[Illustration: FIG. 13
+
+Diagram illustrating the behavior of the _x_-element or sex-chromosome in
+the maturation of the sperm-cell. In one of the two maturation divisions
+(represented here as in the first) it passes undivided to one pole (_a_,
+_b_, _c_), in the other it divides. Since the cell without the _x_-element
+also divides the result is that ultimately from the original primary
+spermatocyte (_a_) four cells are formed (_f_), two with the _x_-element
+and two without it. Half of the spermatozoa therefore will bear an
+_x_-element, half will be without it. In _a_ the ordinary chromosomes,
+arbitrarily indicated as 10, are supposed to have already paired for
+reduction so that the original diploid number in spermatogonia and
+body-cells of the male would be 20 plus the _x_-chromosome.]
+
+
+It has been found, furthermore, that in species in which the males possess
+this extra element the females have two of them. That is, if the original
+number in the somatic cells of the male were twenty-three, twenty-two
+ordinary and one _X_-element, the number in the somatic cells of the
+female would be twenty-four, or twenty-two ordinary and two _X_-elements.
+It has been found that when the chromosomes of the female pair for the
+reduction division, each chromosome uniting with its corresponding fellow,
+the two _X_-elements in the female pair in the usual way so that every
+egg-cell possesses an _X_-element. Thus every mature egg has an
+_X_-element, while only half of the spermatozoa have one. That is, if we
+assume twenty-three as the diploid number present originally in the
+somatic cells of the male and twenty-four as the number in the female,
+then one-half the spermatozoa of the male would contain the haploid number
+eleven, and the other half, the number twelve, whereas every mature ovum
+would contain twelve. Since there are equal numbers of the spermatozoa
+with the _X_-element and without it, and inasmuch as presumably under
+ordinary conditions one kind is as likely to fertilize the egg as the
+other, then there are equal chances at fertilization of producing a zygote
+with two _X_-elements or with but one.
+
+  Thus, Spermatozoon + _X_ by Ovum + _X_ = Zygote + _XX_.
+        Spermatozoon (no _X_) by Ovum + _X_ = Zygote + _X_.
+
+We have already seen that the former is always female, the latter male. It
+thus becomes possible to distinguish the sex of an embryo by counting the
+chromosomes of its cells. This has been accomplished in several cases.
+
+In some instances[1] the conditions may be much more complex than the
+ones indicated--too complex in fact to warrant detailed discussion in an
+elementary exposition--but the principle remains the same throughout, the
+very complexity when thoroughly understood, strengthening rather than
+weakening the evidence. In a few forms an interesting reversal of
+conditions has been found in that the eggs instead of the spermatozoa show
+the characteristic dimorphism.
+
+Just what the exact relationship between sex-differentiation and the
+_X_-element is has never been clearly established. It is possible that
+this element is an actual sex-determinant, in the ordinary cases one
+_X_-element determining the male condition and two _X_-elements producing
+the female condition. On the other hand it might be argued that it is not
+the determining factor but the expression of other cell activities which
+do determine sex; that is, a sex accompaniment. Or again, it may be one of
+several essential factors which must cooperate to determine sex.
+
+
+SEX-LINKED CHARACTERS
+
+The discovery of the remarkable behavior of certain characters in heredity
+which can only be plausibly explained by supposing that they are linked
+with a sex-determining factor still further strengthens our belief in the
+existence of such a definite factor. Such characters are commonly termed
+sex-linked characters.
+
+=Sex-Linked Characters in Man.--=Since there are a number of them in man
+we may choose one of these, such as color-blindness, for illustration. The
+common form of color-blindness known as Daltonism in which the subject
+can not distinguish reds from greens, a condition which seems to be due to
+the absence of something which is present in individuals of normal color
+vision, is far commoner in men than in women. Its type of inheritance,
+sometimes termed "crisscross" heredity, has been likened to the knight
+moves in a game of chess. The condition is transmitted from a color-blind
+man through his daughter to half of her sons. Or, to go more into detail,
+a color-blind father and normal mother have only normal children whether
+sons or daughters. The sons continue to have normal children but the
+daughters, although of normal vision themselves, transmit color-blindness
+to one-half of their own sons. If such a woman marries a color-blind man,
+as might easily happen in a marriage between cousins, then as a rule
+one-half her daughters as well as one-half her sons will be color-blind.
+
+
+[Illustration: FIG. 14
+
+Diagram illustrating the inheritance of a sex-limited character such as
+color-blindness in man on the assumption that the factor in question is
+located in the sex-chromosome (from Loeb after Wilson). The normal
+sex-chromosome is indicated by a black =X=, the one lacking the factor for
+color perception, by a light X. It is assumed that a normal female is
+mated with a color-blind male.]
+
+
+In such cases what appears to be a mysterious procedure becomes very
+simple if we assume that the defective character is associated with the
+sex-determining factor, or to make it concrete let us say with the
+_X_-element. The chart shown in Fig. 14, p. 62, indicates what the
+germinal condition would be under the circumstances. The column to the
+right represents the maternal, the one to the left the paternal line.
+Since two _X_ means female and one _X_ male, and inasmuch as we have
+assumed that the physical basis of the defect to which color-blindness is
+due is conveyed by the _X_-element, we may represent the defective single
+_X_ of the male in outline only (see first row). It is obvious that after
+the reduction divisions (second row) the mature sex-cells of the female
+will each contain a single normal _X_, the corresponding sex cells of the
+male will contain either no _X_ or a defective _X_. Since if any member of
+the class of spermatozoa containing no _X_, fertilizes an egg the
+resulting zygote (row three) will have but one _X_ and that a normal one,
+the individual which develops from the zygote will be normal as regards
+color vision and moreover will be male because the condition one _X_
+always means maleness. On the other hand, if any member of the class of
+spermatozoa containing the defective _X_ fertilizes an egg two
+_X_-elements are brought together and this of itself means femaleness. In
+this case one of the _X_-elements is defective but the single normal _X_
+is sufficient in itself to produce normal color vision. But when it comes
+to the maturation of the sex-cells of this female, the pair of
+_X_-elements are separated in the usual way with the result that half of
+the mature ova contain a normal _X_ and half a defective _X_ (row four).
+Since in a normal male, however, the mature reproductive cells will
+contain either a normal _X_ or no _X_ (fourth row), any one of four
+different kinds of matings may result. A sex-cell carrying normal _X_ of
+the male may combine with an ovum containing normal X producing a normal
+female (row five). Or such a cell may combine with an ovum carrying the
+defective _X_, also producing a female but one who although of normal
+color vision herself, like her mother, is a carrier of the defect. On the
+other hand, any one of the spermatozoa without an _X_ may combine with an
+ovum containing the normal _X_, in which case a normal male is produced
+and, moreover, one who, like his mother's brothers, is incapable of
+transmitting the defect. However, the sperm-cell devoid of an _X_ is just
+as likely to fertilize an ovum carrying the defective _X_, in which event
+the resulting individual, a male, must be color-blind because he contains
+the defective _X_ alone. In other words, the chances are that one-half the
+sons of a woman whose father was color-blind will be color-blind, the
+other half perfectly normal; and that all of the daughters will be of
+normal color vision although one-half of them will probably transmit the
+defect to one-half of their sons. From a glance at the diagram it is
+readily seen also that a color-blind female could result from the union of
+a color-blind man (see first row) and the daughter of a color-blind man
+(see third row). For half of the gametes of such a female would bear the
+defect as would also that half of the gametes of the male which carry _X_,
+hence the expectation would be that half of the daughters of such a union
+would be color-blind and half would be carriers of color-blindness; and
+that half of the sons would be color-blind and half normal. All the sons
+of a color-blind woman would be color-blind because she has only defective
+_X_-elements to pass on.
+
+The inheritance of various other conditions in man follows more or less
+accurately the same course as color-blindness. Among these may be
+mentioned: _hemophilia_, a serious condition in which the blood will not
+clot properly, thus rendering the affected individual constantly liable to
+severe or fatal hemorrhage; near-sightedness (_myopia_) in some cases; a
+degenerative disease of the spinal cord known as _multiple sclerosis_;
+progressive atrophy of the optic nerve (_neuritis optica_); Gower's
+_muscular atrophy_; some forms of _night-blindness_; in some cases
+_ichthyosis_, a peculiar scaly condition of the skin. In one of my own
+tabulations of a case of inheritance of "webbed" digits or _syndactyly_, a
+condition in which two or more fingers or toes are more or less united, a
+sex-linked inheritance is clearly indicated (Fig. 15), although from the
+pedigrees recorded by other investigators this condition usually appears
+in some of both the sons and daughters of an affected individual.
+
+
+[Illustration: FIG. 15
+
+Chart showing the inheritance of a case of syndactyly after the manner of
+a sex-linked character. The affected individuals are represented in black;
+squares indicate males, circles females. The condition is seen to be
+inherited by males through unaffected females.]
+
+
+=The Occurrence of Sex-Linkage in Lower Forms Renders Experiments
+Possible.--=The course followed by such characters in man can be inferred
+only from the pedigrees we can obtain from family histories. Fortunately,
+however, such sex-linkage also occurs in lower animals and we are able
+therefore to verify and extend our observations by direct experiments in
+breeding. Several sex-linked characters have been found to exist in a
+small fruit-fly known as _Drosophila_. Extensive breeding experiments with
+this fly by Professor T. H. Morgan and his pupils have borne out
+remarkably the interpretation that the characters in question are really
+linked with a sex-determining factor.
+
+
+
+
+CHAPTER III
+
+MENDELISM
+
+
+=New Discoveries in the Field of Heredity.--=Writing in 1899, one of
+America's well-known zoologists asserts that, "It is easier to weigh an
+invisible planet than to measure the force of heredity in a single grain
+of corn." And yet only two or three years later we find another prominent
+naturalist saying regarding heredity that, "The experiments which led to
+this advance in knowledge are worthy to rank with those that laid the
+foundation of the atomic laws of chemistry." Again, "The breeding pen is
+to us what the test-tube is to the chemist--an instrument whereby we
+examine the nature of our organisms and determine empirically their
+genetic properties." Here is a decided contrast of statement and yet both
+were justifiable at the time of utterance. For even at the writing of the
+first statement the investigations were in progress which, together with
+the rediscovery of certain older work, were to transfer our knowledge of
+heredity from the realm of speculation to that of experiment and disclose
+certain definite principles of genetic transmission.
+
+Through a knowledge of these principles in fact, the shifting of certain
+characters is reducible to a series of definitely predictable proportions
+and the skilled breeder may proceed to the building up of new and
+permanent combinations of desirable characters according to mathematical
+ratios and, what is of equal importance, he can secure the elimination of
+undesirable qualities. While there are many limitations in the application
+of these principles and while new facts and modifications are constantly
+being discovered concerning them, nevertheless they represent the first
+approximations to definite laws of hereditary transmission that we have
+ever been able to make, and the practical fact confronts us that whatever
+our theoretical interpretations may be, the principles are so definite
+that through their application important improvements of crops and
+domesticated animals have already actually been secured and one may
+confidently expect still others to follow.
+
+=Mendel.--=The principles involved are called the Mendelian principles
+after their discoverer, Gregor Johann Mendel, abbot of a monastery at
+Bruenn, Austria. After eight years of patient experimenting in his cloister
+garden with plants, chiefly edible peas, he published his results and
+conclusions in 1866, in the _Proceedings of the Natural History Society of
+Bruenn_. While known to a few botanists of that day, the full importance of
+the contribution was not recognized, and in the excitement of the
+post-Darwinian controversy, the facts were lost sight of and ultimately
+forgotten.
+
+=Rediscovery of Mendelian Principles.--=In 1900 three men, Correns, De
+Vries and Tschermak, working independently--in different countries, in
+fact--rediscovered the principles and called attention anew to the
+long-forgotten work of Mendel which they had come upon in looking over the
+older literature on plant breeding. These investigators added other
+examples from their own experiments. Since their rediscovery the
+principles have been confirmed in essential features and extended by
+numerous experimentalists with regard to a wide range of hereditary
+characters in both animals and plants.
+
+=Independence of Inheritable Characters.--=It has been found that many
+truly heritable characteristics or traits of an individual, whether plant
+or animal, are comparatively independent of one another and may be
+inherited independently. Where there are contrasted characters in father
+and mother, such as white plumage and black plumage in fowls, smooth coat
+and wrinkled coat in seed, horns and hornlessness in cattle, long fur and
+short fur in rabbits, beard and beardlessness in wheat, albino condition
+and normal condition, etc., there is obviously a bringing together of the
+determiners of the two traits in the resulting offspring. In the third
+generation, however, in the progeny of these offspring, the two distinct
+characters may be set apart again, thus showing that in the second
+generation while perhaps one only was visible, the factors which determine
+both were nevertheless present, and moreover, they were present in a
+separable condition.
+
+=Illustration of Mendelism in the Andalusian Fowl.--=Let us take as a
+simple example the case of the Andalusian fowl. Although it is not a case
+established by Mendel it illustrates certain of the essential conditions
+underlying Mendelism in a more obvious way than the cases worked out by
+Mendel himself. The so-called blue Andalusian fowl results from a cross of
+a color variety of the fowl which is black with one which is white with
+black-splashed feathers. The result is the same irrespective of which
+parent is black. When bred with their like, whether from the same parents
+or different parents, these blue fowls produce three kinds of progeny,
+approximately one-fourth of which are black like the one grandparent,
+one-fourth white like the other grandparent, and the remaining half, blue
+like the parents (Fig. 16). Moreover, the black fowls obtained in this way
+will, when interbred, produce only black offspring and the same is true of
+the white fowls. To all appearances as far as color is concerned they are
+of as pure type as the original grandparents. With the blue fowls,
+however, the case is different, for when bred together they will produce
+the same three kinds of progeny that their parents produced and in the
+same proportions. Again the white and the black are true to type but the
+blue will always yield the three classes of offspring and this through
+generation after generation.
+
+
+[Illustration: FIG. 16
+
+Diagram showing the scheme of inheritance in the blue Andalusian fowl.]
+
+
+These facts may be illustrated graphically as follows where the word
+"black" indicates the original black parent, "white" the original white
+(black splashed) parent and "blue" the hybrid offspring.
+
+  Parental
+  Generation (P)          Black x White              Black x White
+                                |                          |
+  First Filial                  |                          |
+  Generation (F_{1})          Blue          x           Blue
+                                             |
+                        +------------------------------------------+
+                        |                    |                     |
+  Second Filial       Black                 Blue                 White
+  Generation (F_{2})  (25%)                 (50%)                (25%)
+                        |                    |                     |
+                        |        +-------------------------+       |
+                        |        |           |             |       |
+  Third Filial        Black   Black         Blue          White  White
+  Generation (F_{3})    |     (25%)         (50%)         (25%)    |
+                        |        |           |             |       |
+                        |        |     +-------------+     |       |
+                        |        |     |     |       |     |       |
+  Fourth Filial       Black   Black  Black  Blue   White  White  White
+  Generation (F_{4})                 (25%)  (50%)  (25%)
+
+=The Cause of the Mendelian Ratio.--=Concerning the cause of this peculiar
+ratio of inheritance in crossed forms Mendel suggested a simple
+explanation. Animals or plants that can be cross-bred, obviously must be
+forms that produce a new individual from the union of two germ-cells, one
+of which is provided by each parent. Mendel's idea was that there must be
+some process of segregation going on in the developing germ-cells of each
+hybrid whereby the factors for the two qualities are set apart in
+different cells with the result that half of the germ-cells of a given
+individual will contain the determiner of one character and half, the
+determiner of the other. That is, a given germ-cell carries a factor for
+one or the other of the two alternate characters but not the factors for
+both. In a plant, for example, in the male line, half of the pollen grains
+would bear germ-cells carrying the determiner of one character and half,
+that of the other. Similarly, in the female line, half of the ovules would
+contain the determiner of the one character and half, that of the other.
+Likewise in animals as regards such pairs of characters there would be two
+classes of germ-cells in the male and two in the female. In the case of
+the blue Andalusian fowls under discussion this would mean that half of
+the mature germ-cells of the male carry the black-producing factor, and
+half carry the white-producing factor, and the same is true of the
+germ-cells of the female. Thus when two such crossed forms are mated,
+there are, by the laws of chance, four possible combinations, namely: (1)
+white-determining sperm-cells and white-determining ovum; (2)
+white-determining sperm-cells and black-determining ovum; (3)
+black-determining sperm-cells and white-determining ovum; and (4)
+black-determining sperm-cells and black-determining ovum. Manifestly, the
+first combination can only give white offspring; the second, white and
+black, gives blue (by such a cross the original blues were established);
+likewise, the third, black and white, gives blue; and the fourth
+combination can only give black offspring. This matter may be graphically
+represented by the following formulae in which B indicates the determiner
+of Black in the germ-cell and W the determiner of White: [male] signifies
+male; [female] female.
+
+
+IN THE ORIGINAL PARENTS
+
+  W x B = WB = Blue
+
+IN THE HYBRIDS
+
+  [male] [female]
+  germ-  germ-
+  cells  cells     [male] [female]
+    W----W          W   x   W = WW = White
+      \/            W   x   B = WB = Blue
+      /\      or    B   x   W = BW = Blue
+    B----B          B   x   B = BB = Black
+
+Thus of the four possible combinations one only can produce white fowls,
+two (WB or BW) can produce blue fowls, and one black fowls. That is, the
+ratio is 1:2:1 or the 25, 50 and 25 per cent., respectively, of our
+diagram. The black fowls or the white fowls will breed true in subsequent
+generations when mated with those of their own color because the
+determiner of the alternative character has been permanently eliminated
+from their germ-plasm; but the blue fowls will always yield three types of
+offspring because they still possess the two classes of germ-cells.
+
+=Verification of the Hypothesis.--=The hypothesis that germ-cells of
+crossed forms are of two classes with respect to a given pair of Mendelian
+characters is further substantiated by the following facts. If in the case
+of the fowls under discussion one of the blue fowls is mated with an
+individual of the white variety, half of the progeny will be blue and
+half white. For the hybrid has two kinds of germ-cells, black producing,
+which we have designated by the letter B, and white producing (or W) in
+equal number while the white parent has only one kind, white producing. It
+is obvious that if half the germ-cells of the hybrid form are of the type
+B then half the progeny will be of the BW type, which is blue, and the
+other half will be of the WW type, which is white. In the same way if we
+mate a hybrid and a black fowl, half of the progeny will be black and half
+will be blue, that is, there could only be WB and BB types.
+
+The fact must not be lost sight of that since the pairings are wholly
+determined by the laws of chance the proportions are likely to be only
+approximate. It is obvious that the greater the number of individuals, the
+nearer the results will approach the expected ratio.
+
+
+DOMINANT AND RECESSIVE
+
+=One Character May Mask the Other.--=In a large number of cases, however,
+the actual condition of affairs is not so evident as in the Andalusian
+fowl, for instead of being intermediate or different in appearance, the
+generation produced by crossing resembles one parent to the exclusion of
+the other. Such an overshadowing is spoken of as _dominance_, and the two
+characters are termed _dominant_ and _recessive_. Thus when brown
+ring-doves and white ring-doves are mated the progeny are all brown, or if
+wild gray mice are mated to white mice the progeny are all gray. So black
+is dominant to white in rose-comb bantams; brown eyes to blue eyes in man;
+beardlessness to beard in wheat, and likewise rough chaff to smooth, and
+thick stem to thin; tallness to dwarfness in various plants; normal
+condition to the peculiar waltzing condition in the Japanese waltzing
+mouse. Numerous other cases might be cited but these are sufficient to
+illustrate the condition.
+
+=Segregation in the Next Generation.--=But now the question arises, what
+do such crosses as show dominance transmit to the next generation?
+Experiments show regarding any given pair of these alternate characters
+that they are set apart again in the succeeding generation, returning in a
+definite percentage to the respective grandparental types.
+
+
+[Illustration: FIG. 17
+
+Diagram showing the scheme of inheritance in guinea-pigs when black and
+albino forms are crossed.]
+
+
+=Dominance Illustrated in Guinea-Pigs.--=In guinea-pigs for example (Fig.
+17), when an individual (either male or female) of a black variety, is
+crossed with one of a white variety, the F_{1} generation are all black
+like the black parent. When these are interbred or bred with other blacks
+which have had one black and one white parent, only two visible types of
+progeny appear, viz., black and white, and these approximately in the
+ratio of three to one.
+
+Analysis by further breeding shows, however, that there are in reality
+three types, but since dominance is complete the pure extracted dominant
+and the mixed dominant-and-recessive type are indistinguishable to our
+eye. That is, while the blacks are three times as numerous as the whites,
+two out of every three of these blacks are really hybrid and correspond to
+the blue fowls of our former example.
+
+The condition is readily comprehended when expressed diagrammatically
+thus:
+
+  Generation P           Black x White       Black x White
+                               |                 |
+  Generation F_{1}        Black (White)  x   Black (White)
+                                         |
+                      +-------------------------------------+
+                      |                  |                  |
+  Generation F_{2}  1 Black       2 Black (White)       1 White
+
+In other words, the germ-cells of the one original parent (Gen. P) would
+contain only determiners for black and that of the other parent would
+contain only determiners for white. The condition of the individuals
+produced by the cross would be represented by the formula B(W). But these
+determiners segregate in the germ-cells of the crossed form, whether it be
+male or female, into B and W. Hence half the spermatozoa of the male
+hybrid (generation F_{1}) would carry the B determiners and half the W
+determiners. The same is true of the mature ova of the female hybrid.
+Consequently, in mating there are always four equally possible
+combinations, viz., BB, B(W), (W)B, and WW. Since B is always dominant
+three out of the four matings would yield black individuals, or in other
+words the ratio would be 3:1.
+
+The pure blacks when mated together will breed true in subsequent
+generations, likewise the whites, but the blacks carrying white as a
+recessive will yield when interbred the same ratio of whites and black as
+did their hybrid parents (Fig. 17, p. 75).
+
+=Terminology.--=As work in the study of Mendelian inheritance has
+progressed and expanded the need of a more precise terminology has become
+evident and such is gradually being established. Thus Professor Bateson
+has coined the term "allelomorph" (Gk. _one another_, and _form_) to
+express more exactly what we have thus far been calling a pair of
+alternate or opposite characters. In the blue Andalusian fowls discussed,
+the white condition in the one parent is the allelomorph of the black
+condition in the other. The term generally means one of the pair of
+Mendelian characters themselves as expressed in the individual plants or
+animals but when the germinal basis of such phenomena is under discussion,
+it is sometimes used to refer to the determiners of such characters. And
+by determiner is meant simply the condition which is necessary in the germ
+to bring about the occurrence of a definite character. For example, when
+we are studying a cross between a red flower and a white flower with
+reference to the color factors, the difference between the two plants may
+lie in the fact that one produces a red coloring matter and the other
+does not. That is, the determiner for red is absent from the white
+variety. What the exact relation of color production is to the parts of
+the germ-cell we do not know. It could be the function of a single
+definite body or the resultant of several cooperating bodies. The latter
+is far more likely to be the case. We may suppose that a group of
+cooperating substances function to produce red in the red flower but that
+in the white flowers one of these bodies is absent or fails to perform its
+red-producing function.
+
+It is customary where practicable to refer to the determiner of a
+character by the initial letter of the name of the character. The letter
+when written as a capital indicates the determiner but when written as a
+small letter the absence of the determiner. Thus R may be taken to
+represent the determiner for red coloring matter and r its absence. It is
+convenient also to have a brief symbol to denote a given generation and
+for this purpose Bateson has introduced the symbol F_{1} for the hybrid
+progeny of the first cross, the initial letter of the word "filial." F_{2}
+would indicate the next generation, F_{3} the third and so on. Likewise P
+denotes the original parent generation.
+
+=The Theory of Presence and Absence.--=Many, if not all, allelomorphs
+consist of the presence and absence respectively of a given determiner. In
+such cases the character represented by the presence of the determiner is
+dominant over the character represented by the absence of a determiner.
+Thus in the crosses from the wild gray mice and albino mice the progeny
+are all gray mice since one parent had the determiner or group of
+determiners for grayness and the hybrid offspring must also possess it.
+Likewise the presence of black in black guinea-pigs is dominant to its
+absence in albino guinea-pigs and the resulting progeny are all black.
+
+However, it has already been mentioned that beardlessness in wheat is
+dominant to beard and that the absence of horns in cattle is dominant to
+their presence, that is, the progeny of hornless by horned cattle are
+without horns except for occasional traces of imperfect horns. Facts like
+these would seem at first sight to contradict the assertion just made that
+presence is dominant to absence, but it is fairly well established that in
+such cases one is not dealing with true absences but with suppressions.
+The polled breeds of cattle, for example, are hornless not because of the
+absence of determiners for horns but because of the presence of an
+additional inhibiting factor which prevents these determiners from
+functioning. The horned breeds are without this inhibitor. When horned and
+hornless individuals are crossed the presence of the inhibitor from one
+line of ancestry is sufficient to suppress the development of horns in the
+progeny. A similar explanation would, of course, apply to beardlessness in
+wheat.
+
+In writing double-lettered formulae to denote the determiners of characters
+in hybrids the condition is represented merely by the capital and small
+letter. Thus Rr indicates that red is dominant to its absence.
+
+=Additional Terminology.--=In pure breeds where the determiners are alike
+as BB in black or bb in albino guinea-pigs, the individual is said to be a
+_homozygote_ (like things united) with reference to that character, while
+in those in which the determiners are unlike, as Bb, the individual is
+termed a _heterozygote_ (unlike things united) with reference to the
+character. Or to use the adjective forms, a pure black guinea-pig is
+homozygous for black pigment, an albino guinea-pig is homozygous for
+absence of pigment, while a cross between the two is heterozygous for
+pigment. Also, where the determiner of a given character is present in
+double quantity, that is, from both lines of ancestry, the individual is
+said to be _duplex_, where represented in only the single form as in
+heterozygous individuals, _simplex_, and where the determiner is absent
+entirely, _nulliplex_, with reference to the character in question. Thus
+black guinea-pigs of formula BB are duplex with regard to the determiner
+for black color, individuals of formula Bb are simplex with reference to
+this determiner, and those of formula bb are nulliplex.
+
+A heterozygote in which dominance prevails can be identified with
+certainty by breeding to a known recessive and noting the kind of
+offspring produced. If the individual was really a heterozygote,
+approximately fifty per cent. of the offspring should be of the recessive
+type.
+
+=Dominance Not Always Complete.--=As a matter of fact close inspection
+shows that in numerous instances dominance is not absolute since traces of
+the recessive character may be detectable. For example, in the cross
+between smooth and bearded wheat while smoothness is regarded as the
+dominant character and beardlessness as the recessive, nevertheless in the
+hybrid offspring a slight tendency toward bearding is not infrequently
+seen. Or again when horned breeds of cattle are crossed with hornless
+ones, a small proportion of such progeny will show traces of imperfect
+horns.
+
+In some cases instead of either character dominating the other a form
+intermediate between the two parents may result, as we have seen already
+in the case of the Andalusian fowl. Thus, certain white-flowered plants
+and certain red-flowered plants when crossed produce pink hybrids, and
+longheaded and shortheaded wheats when crossed give offspring with heads
+of intermediate length. Or again, crosses between white and red cattle may
+yield red roans, and between black and white cattle, blue roans.
+
+Thus, while for such pairs of alternative characters as have been studied,
+dominance to some considerable degrees at least, seems to be the rule,
+still we have gradations down to the intermediate condition, and in some
+instances the hybrid with respect to a given character may be unlike
+either parent. The things of chief importance in the Mendelian discovery
+are the independent, unitary nature of the characters and their
+segregation in the offspring of cross-bred forms.
+
+=Modifications of Dominance.--=It should be noted also that there is such
+a condition as _delayed dominance_. Davenport found, for example, that
+chicks produced by crossing pure white with pure black Leghorn fowls are
+speckled black and white, but later in the adult form white becomes
+dominant. Likewise conditions of delayed dominance are known in man in
+eye-color and notably in color of hair. Some few cases have been recorded
+where a character is dominant at one time, recessive at another.
+According to Davenport extra toe in fowls may behave in this way.
+
+=Mendel's Own Work.--=Mendel[2] himself worked out his principles on seven
+pairs of characters which he found in common culinary peas. Placing the
+dominant characters first, these may be enumerated as follows: (1) Tall by
+dwarf; (2) green pod (unripe) by yellow; (3) pod inflated by pod
+constricted between the individual peas; (4) flowers arranged along the
+axis of the plant by flowers bunched together at the top; (5) seed skin
+colored by seed skin white; (6) cotyledons yellow by cotyledons green; (7)
+seed rounded by seed wrinkled.
+
+He found that each pair of characters followed the same law as any other
+pair when more than one pair of the characters occurred in the same
+plants, but that each pair behaved independently of the other. The meaning
+of this is that we may get various combinations of characters not
+associated in the original pure stocks, the number of such combinations
+depending on the number of pairs of allelomorphs there are.
+
+
+DIHYBRIDS
+
+=Getting New Combinations of Characters.--=Since this principle is well
+illustrated in peas, let us take two pairs of their characters, viz.,
+greenness and yellowness (of the cotyledons) and roundness and angularity
+to see exactly what happens when two pairs of allelomorphs are involved.
+When a specific kind of yellow pea is crossed with a particular kind of
+green pea the offspring are always yellow (Fig. 18, opposite p. 84). When
+these hybrids (generation F_{1}) are self-fertilized there is the usual
+Mendelian segregation; one-fourth the resulting offspring will be green,
+one-fourth pure yellow, and one-half, although yellow in appearance, will
+be of the mixed type. The exact numbers found by Mendel were 6,022 yellow
+seeds to 2,001 green seeds. Now of the original peas (generation P) the
+yellow ones are round and the green ones angular (really wrinkled).
+Choosing this roundness and angularity respectively as a pair of
+characters they are found to follow the same law that the colors follow
+(Mendel obtained in the F_{2} generation 5,474 round and 1,850 wrinkled
+seed), but independently of the latter. For while in the progeny of the
+hybrids (Gen. F_{1}), twenty-five per cent. will be round and of pure type
+as regards roundness, twenty-five per cent. angular, and fifty per cent.
+round but containing hidden factors of angularity (i. e., roundness is
+dominant), the roundness and the yellowness, or the angularity and the
+greenness will not always go together as they did in the original
+grandparental strains, but there will be in addition some new types of
+round green peas and some of angular yellow ones. That is, the factors of
+color and of shape have been inherited independently of one another, so
+that instead of the two original kinds of peas, four have been produced,
+viz., (1) round-yellow (one of the original types); (2) round-green (new
+type); (3) angular-yellow (new type); and (4) angular-green (one of the
+original types). Furthermore, these will be found to stand in the ratio of
+9:3:3:1 respectively.
+
+=Segregations of the Determiners.--=How these combinations come about in
+this definite proportion is easily understood if the matter is expressed
+in terms of determiners and the possible matings tabulated (Fig. 18). If
+we represent the yellow determiner by Y and the green determiner by y, and
+likewise the determiners of roundness and angularity by R and r
+respectively, then the formulae for the determiners of these two pairs of
+characters in the body cells (that is, in the unreduced condition) of the
+pure forms and of the F_{1} generation hybrids respectively are as
+follows:
+
+  In pure round yellow peas       RR YY
+  In pure angular green peas      rr yy
+  In the hybrid                   Rr Yy
+
+But now in the segregation of these determiners in the germ-cells of the
+hybrids (generation F_{1}) the pair of determiners Rr and the pair Yy
+operate entirely independently of one another. Their only compulsion is
+that each pair be separated into the single determiners, R and r in the
+one case and Y and y in the other. So in the separating division which
+brings about this divorcement R separates from r irrespective of whether
+it is accompanying Y or y into the resulting daughter cell. Thus in some
+cases R and Y would pass into one germ-cell, in others R and y, in others
+r and Y, and in still others r and y, depending entirely upon the
+chance relations of the respective pairs to the plane of division. That
+is, the segregation is equally likely to be RY/ry giving gametes RY and
+ry, or Ry/rY giving gametes Ry and rY.
+
+
+[Illustration:
+
+       \[Female]
+  [Male]\   RY       Ry       rY       ry
+         +-------+--------+--------+--------+
+    RY   | RRYY  |  RRYy  |  RRYY  |  RrYy  |
+         +-------+--------+--------+--------+
+    Ry   | RRYy  |  RRyy  |  RrYy  |  Rryy  |
+         +-------+--------+--------+--------+
+    rY   | RrYY  |  RrYy  |  rrYY  |  rrYy  |
+         +-------+--------+--------+--------+
+    ry   |  RrYy |  Rryy  |  rrYy  |  rryy  |
+         +-------+--------+--------+--------+
+
+      (1) 1 RRYY    (4) 2 RrYY    (7) 1 rrYY
+      (2) 2 RRYy    (5) 4 RrYy    (8) 2 rrYy
+      (3) 1 RRyy    (6) 2 Rryy    (9) 1 rrYy
+                      9:3:3:1
+
+FIG. 18
+
+Diagram showing the possible combinations arising in the second filial
+generation (F_{2}) following a cross between yellow, round (YYRR) and
+green, angular or wrinkled (yyrr) peas. Y, presence of factor for yellow;
+y, absence of such a factor; R, presence of factor for smoothness or
+roundness; r, absence of such a factor; [male] male; [female] female.]
+
+
+=Four Kinds of Gametes in Each Sex Means Sixteen Possible
+Combinations.--=There are, therefore, with reference to the two pairs of
+characters under consideration, four kinds of gametes (or mature
+germ-cells) produced in equal numbers in each hybrid, viz., RY, Ry, rY,
+and ry. That is, in the first type roundness and yellowness are
+associated, in the second roundness and greenness, in the third angularity
+(lack of roundness) and yellowness, and in the fourth angularity and
+greenness.
+
+But since both males and females have these four kinds of gametes, when
+they are mated there will be sixteen possible combinations. These may be
+tabulated as in Fig. 18, opposite p. 84.
+
+=The 9:3:3:1 Ratio.--=While there are sixteen possible and equally
+probable combinations, these will give only nine distinct kinds because
+some of the matings are alike. The numbers of the various kinds of matings
+are as follows:
+
+  (1) 1 RRYY    (4) 2 RrYY    (7) 1 rrYY
+  (2) 2 RRYy    (5) 4 RrYy    (8) 2 rrYy
+  (3) 1 RRyy    (6) 2 Rryy    (9) 1 rrYy
+
+Since roundness (R) and yellowness (Y) are dominant to angularity (r) and
+greenness (y) in all combinations containing R or Y, the alternative
+determiners r or y would be obscured, with the result that individuals
+having certain of the combinations would look alike to our eye. For
+example, the individuals represented by numbers 1, 2, 4 and 5, since they
+contain dominant R and Y, would all appear round and yellow, although in
+reality No. 1 would be the only one of pure type (both elements
+homozygous) and hence the only one that would breed true in subsequent
+generations. The two individuals represented in No. 2 would breed true as
+regards shape (RR) but not color (Yy). Just the reverse is true of No. 4
+since shape is heterozygous (Rr) and color homozygous (YY). The four
+individuals represented in No. 5 are heterozygous with regard to both
+elements. Thus nine individuals (1 plus 2 plus 2 plus 4 = 9) represented
+in Nos. 1, 2, 4 and 5 would be round and yellow, three individuals (Nos. 3
+and 6) would be round and green, three (Nos. 7 and 8) would be angular and
+yellow, and only one (No. 9) would be angular and green. That is to say,
+the four classes discernible to the eye in generation F_{2} would be
+present in the ratio of 9:3:3:1.
+
+=Phenotype and Genotype.--=Forms such as those represented in Nos. 1, 2, 4
+and 5 which to the eye appear to be alike, regardless of their germinal
+constitution, are said to be of the same _phenotype_. Those of the same
+hereditary constitution, as the two individuals represented in No. 8, or
+the four individuals in No. 5, are said to be of the same _genotype_, that
+is, they are of identical gametic constitution.
+
+As we have seen, it is from the genotypical not the phenotypical
+constitution that an offspring is derived and what a given form will bring
+forth depends then on its genotype.
+
+=Crosses With More Than Two Pairs of Characters.--=In crosses in which
+more than two pairs of contrasted characters are involved the underlying
+principles are in no way different, only with each pair of additional
+characters there is, of course, a greater number of possible combinations.
+Thus with three pairs of characters there will be eight different classes
+of gametes in each sex and consequently sixty-four possible combinations
+in mating, giving eight different phenotypes in the proportion of
+27:9:9:9:3:3:3:1. The largest class manifests the three dominant
+characters; the smallest class, the three recessives; the three classes in
+the proportion of 9 each exhibit two dominant and one recessive
+characters; and those in the proportion of 3 each display two recessive
+and one dominant characters.
+
+
+THE QUESTION OF BLENDED INHERITANCE
+
+We come now to certain types of inheritance in which there seems to be a
+true fusion or blend of the contributions from the two parents, the
+intermediate condition apparently persisting in subsequent generations
+without segregation. Numerous cases of blended inheritance have been cited
+in earlier literature of heredity, but as our knowledge of genetics has
+progressed many experimental breeders have come to believe that the
+blends in such cases are apparent rather than real and that the phenomena
+can be best explained on a non-blending unit-character basis, just as we
+would explain ordinary Mendelian phenomena.
+
+=Nilsson-Ehle's Discoveries.--=To get their point of view we may review
+certain experiments on wheat made by Nilsson-Ehle, together with their
+Mendelian interpretation. Nilsson-Ehle found that a certain brown-chaffed
+wheat when crossed with a white-chaffed strain yielded a brown-chaffed
+hybrid, apparently in accordance with the simple principle of Mendelian
+dominance. But these heterozygous brown-chaffed individuals did not in
+turn give the expected ratio of 3:1 in the F_{2} generation but a ratio of
+15 brown to 1 white, and furthermore the browns were not all of the same
+degree of brownness. To be exact, from fifteen different crosses of the
+strains he obtained 1,410 brown-chaffed and 94 white-chaffed plants.
+
+This apparent anomaly in segregation was easily explained, however, when
+it was finally figured out that there were really two independent
+determiners for brown color, either of which alone could produce a brown
+individual, but when combined produced individuals of correspondingly
+deeper shades of brown. In such a case then Nilsson-Ehle discovered that
+he was dealing merely with a Mendelian dihybrid where two different
+determiners B and B' and their respective absences b and b' are involved.
+The original brown wheat had both B and B' and the original white b and
+b'. The formula for the F_{1} heterozygote was therefore BbB'b'. The four
+possible types of gametes for male and female are BB', Bb', bB', bb', and
+the tabulation would be as follows:
+
+       +-----------------------------------
+       |  BB'   |  Bb'   |  bB'   | bb'
+  -----+--------+--------+--------+--------
+   BB' | BBB'B' | BBB'b' | BbB'B' | BbB'b'
+  -----+--------+--------+--------+--------
+   Bb' | BBB'b' | Bb'Bb' | BbB'b' | Bbb'b'
+  -----+--------+--------+--------+--------
+   bB' | BbB'B' | BbB'b' | bbB'B' | bbB'b'
+  -----+--------+--------+--------+--------
+   bb' | BbB'b' | Bbb'b' | bbB'b' | bbb'b'
+  -----------------------------------------
+
+It will be observed that there are more brown determiners in some
+combinations than others. For instance one of the sixteen contains four
+such determiners, viz., B, B', B, B', four contain three determiners, six
+contain two, four contain only one, and one contains none. Thus all but
+one of the sixteen contain at least one determiner and will therefore be
+brown in color but the depth of color will depend on the number of brown
+determiners in a given individual. This is more graphically represented in
+Fig. 19, p. 90. The largest number of similar individuals, six in all,
+contain two determiners each and represent an intermediate "blend" between
+the original brown-chaffed and white-chaffed strains. The deeper and the
+lighter browns due to more or fewer determinants in an individual would if
+one did not know the units in this case look like the fluctuations around
+this average which we might expect in a blend.
+
+
+[Illustration: FIG. 19
+
+Diagram illustrating the proportionate distribution of determiners where
+either of two different determiners produces the same character, the
+degree of expression of the character depending on the number of the
+determiners present. The numerals indicate the number of brown determiners
+present in an individual.]
+
+
+Nilsson-Ehle found another significant case in wheat where one particular
+red-grained strain of Swedish wheat when crossed with white-grained
+strains produced red-grained offspring, but when these were interbred the
+F_{2} generation gave approximately sixty-three red to one white-grained
+individual. Here it was found that in the original red wheat there are
+three separate determiners which act independently of one another in
+heredity, any one of which would make red color; and that they together
+with their absences simply follow the Mendelian laws for a trihybrid.
+
+=Such Cases Easily Mistaken for True Blends.--=If we should tabulate the
+possible combinations as we did the dihybrid we should see that we would
+get individuals having varying numbers of red determiners. Only one of the
+sixty-four possible combinations would be without a factor for red. Of the
+sixty-four, one would have six determiners for red, six would have five,
+fifteen would have four, twenty would have three, fifteen would have two,
+six would have one, and one would have none. Since here every additional
+red factor means deeper redness in the individual there would be varying
+degrees of redness in the F_{2} generation with those having three
+determiners, the largest group, standing apparently intermediate. Not
+knowing the factors involved we might easily mistake such a case for a
+true blend with fluctuations about an average intermediate form.
+Nilsson-Ehle finally proved his interpretation by rearing an F_{3}
+generation from isolated and self-fertilized plants of this F_{2}
+generation.
+
+This same principle of cumulative determiners has also been established in
+America by East with field corn.
+
+As the number of duplicate determiners increases it can be readily seen
+that the number of apparent blends of different degrees of intermediacy
+between the two extremes would rapidly increase.
+
+=Skin-Color in Man.--=In man, the skin-color of the hybrids between
+negroes and whites is often cited as a case of blended inheritance in
+contradistinction to Mendelian inheritance. The skin-color of the mulatto
+of the F_{1} generation is intermediate between that of the white and
+black parent. This same degree of intermediacy is commonly supposed to
+persist in subsequent generations, but as a matter of fact, careful
+investigation has shown that while mulattoes rarely produce pure white or
+pure black children, there is considerably greater range in the shades of
+color in the F_{2} generation and subsequent generations than in the F_{1}
+generation. This is exactly what one would expect of a Mendelian character
+in which several cooperating factors were involved. Indeed, Davenport who
+has made extensive studies[3] on the inheritance of skin-color in man has
+come to the conclusion that the case is really one of Mendelian
+inheritance in which several factors for skin-color are concerned. Even
+the skin of a white man is pigmented in some degree under normal
+conditions. Davenport has shown in the skin of both whites and blacks that
+there is a mixture of black, yellow and red pigments. He concludes that
+"there are two double factors (AABB) for black pigmentation in the
+full-blooded negro of the west coast of Africa and these are separably
+inheritable." Since these factors are lacking in white persons the
+intermediate color of an F_{1} mulatto would therefore be heterozygous for
+pigmentation, and subsequent generations, following the laws for
+segregation where a number of factors are concerned, would show different
+degrees of color because of the varying combinations of factors.
+
+=Some Investigators Would Question the Existence of Real Blends.--=Still
+other reputed blends such as ear length in rabbits and the like have been
+shown to be analyzable into Mendelian behavior if one will but postulate
+numerous or multiple factors. Just how far we are justified in so
+accounting for blends has not yet been established. Some of our most
+careful experimentalists in heredity still believe that real blends exist,
+particularly where the character is quantitatively expressed--that is, as
+more or less of a given size or amount--while others would maintain that
+all alleged blends will probably be found to be resolvable into factors
+which follow Mendelian rule. It must be left for future investigations to
+demonstrate which school is correct.
+
+
+THE PLACE OF THE MENDELIAN FACTORS IN THE GERM-CELLS
+
+=Parallel Between the Behavior of Mendelian Factors and Chromosomes.--=The
+question arises as to whether there is any evidence from the study of
+germ-cells themselves to bear out the Mendelian conception of separation
+of contrasted characters in the gametes of the F_{1} generation. In the
+discussion of the maturation of germ-cells (Chap. II) it has already been
+seen that the chromosomes of the germ-cells are in all probability
+arranged in homologous pairs, one member being of maternal and the other
+of paternal origin, and that furthermore they are closely associated with
+the phenomena of heredity. And since in maturation there is an actual
+segregation of the chromosomes into two sets, half going to one cell and
+half to its mate, a physical basis adequate to the necessities of the case
+is really at hand. It will be recalled that the individuals of a pair
+separate in such a way at the reduction division that the paternal member
+goes to one cell and the maternal member to the other, although each pair
+seemingly acts independently of the others with the result that any mature
+germ-cell may contain chromosomes from each of the original parents but
+never the two chromosomes which earlier made up a pair. The close parallel
+between the behavior of chromosomes and the behavior of Mendelian factors,
+although the two sets of phenomena were discovered wholly independently of
+each other, is obvious. If we suppose that each chromosome bears the
+determiner of a Mendelian character and that chromosomes bearing
+allelomorphic characters make up the various pairs which are seen in the
+early germ-cells of an individual before reduction occurs, then the
+segregation of the individuals of an allelomorphic pair into different
+gametes must result in consequence of the passing of the corresponding
+chromosomes into separate gametes. Fig. 20, p. 95, from Professor Wilson
+represents equally well the segregations of pairs of chromosomes or pairs
+of Mendelian characters.
+
+
+[Illustration: FIG. 20
+
+Diagram showing union of factors from the two separate parents in
+fertilization and their segregation in the formation of germ-cells (after
+Wilson). With four pairs of factors (_Aa_, _Bb_, _Cc_, _Dd_), sixteen
+types of gametes are possible, as shown in the series of small circles at
+the right. The same diagram equally well represents the pairings and
+segregations of chromosomes.]
+
+
+=A Single Chromosome not Restricted to Carrying a Single Determiner.--=It
+has been objected that there may be more pairs of independently heritable
+allelomorphic characters than there are pairs of chromosomes. It is true
+that there are more pairs of characters than pairs of chromosomes but
+there is no reason for supposing that a given chromosome is restricted to
+carrying a single unit-determiner. On the contrary it probably carries
+several or many. Some workers have pointed out that certain units might be
+interchanged during the pairing of chromosomes before the reduction
+division, others that inasmuch as the chromosomes become diffuse and
+granulated during the intervals between divisions it is not improbable
+that the individual units may become separated from their original system
+during such times and that it is a matter of chance into which of the
+homologous chromosomes, A or a, they enter with the re-establishment of
+the chromosomes. On the other hand, cases are known where two or more
+separate characters are permanently associated in inheritance, that is, if
+they enter a crossed form together they come out together in the
+grandchildren as if they were carried in the same unit-body in the
+germ-cell. The only observable unit-bodies that fulfil the necessities of
+such cases are the chromosomes. This tendency of characters to exist in
+groups which are inherited independently of one another is coming more and
+more into evidence as we penetrate farther into the intricacies of
+inheritance, and it is exactly what we would expect on the supposition
+that each chromosome carries the determiners of a number of characters
+instead of a single one.
+
+
+
+
+CHAPTER IV
+
+MENDELISM IN MAN
+
+
+=The Mendelian Principles Probably Applicable to Many Characters of
+Man.--=We are really just beginning to make the proper observations and
+collect the necessary data with reference to the application of Mendelian
+principles to the traits of man. Yet brief as has been our study we have
+disclosed much significant evidence which makes it seem highly probable
+that many of his characters, good and bad, of mind and body are as
+subservient to these laws as are the traits and features of lower forms.
+Davenport and Plate record over sixty human characters or defects which
+are seemingly inherited in Mendelian fashion. Although about fifty of
+these are pathological or abnormal conditions, this does not mean that
+such conditions are more prone to follow Mendelian inheritance but merely
+that being relatively conspicuous or isolated they are easier to follow
+and tabulate.
+
+=Difficult to get Correct Data.--=While it must be said that in many cases
+no simple form of Mendelian tabulation has been unequivocally established,
+yet the general behavior of the various inheritable traits in question is
+so obviously related to the conventional Mendelian course that there seems
+little reason for doubting that they are at bottom the same. Failure to
+obtain exact proportions may be attributable in part to the probability
+that what we loosely regard as a character should in reality be analyzed
+into more elemental components, and above all to the fact that from the
+very nature of the conditions under which human records must be obtained,
+there is considerable chance of inaccuracy or error in such accounts. How
+many human traits follow Mendelian rules remains largely for future
+investigators to establish.
+
+We are handicapped at the outset in man by the many difficulties of
+getting correct data from the genealogies on which we must depend, or in
+fact of getting any genealogy at all, for in this country at least, most
+families keep imperfect records of births and deaths and many of the
+institutions for the various kinds of defectives have little in their
+records that will help us in following out hereditary conditions. Then in
+matters of disease we meet with the fact that many former diagnoses were
+erroneous. In yet other cases, and this is particularly true among mental
+and moral defectives, we are often not sure of the paternity of a given
+child. Furthermore, one is likely to be misled by the proportions which
+may occur in the very limited number of children of any given couple.
+
+Still other difficulties exist. Among these is the fact, for example, that
+in many cases of defect or susceptibility to disease, a given individual
+in the stock may have the trait in an expressible and transmissible form,
+yet it never comes to expression because that individual has been
+fortunate enough to escape the environmental stimulus which would call it
+forth. Thus one highly susceptible to tuberculosis might escape infection,
+or persons hovering on the verge of insanity might never receive the
+precipitating stimulus which would topple them into actual insanity; yet
+each would be wrongfully recorded in a genealogy looking to such traits as
+perfectly normal. Or again if it be a question of intellectual brilliancy
+as shown by accomplishment in the realm of scholarship, or of worldly
+affairs, the ones who although possessing them have had no chance to
+display unusual talents would be tabulated as average whereas in fact they
+should be recorded as of high rank. That this is particularly likely to
+happen in the case of women is evident.
+
+=A Generalized Presence-Absence Formula for Man.--=In man as in lower
+forms some characters or traits are due presumably to the presence of
+determiners or to their absence. Likewise, dominance and recessiveness are
+as much in evidence, for in tracing back pedigrees of various traits we
+find the same forms of tabulation that obtain for these conditions in
+plants and lower animals hold good. For typical cases in man let us use a
+generalized presence-absence formula and the arbitrary symbol A for the
+presence of the determiner of the character (double in the individual,
+single in the germ) and a for its absence. Thus AA represents a condition
+in which similar determiners have been derived from both parents and the
+individual is _duplex_ as regards the character in question; each mature
+germ-cell will have the determiner. Aa represents a condition in which the
+individual has received the determiner from only one parent and is
+therefore _simplex_ with regard to the character; half of the gametes of
+such an individual will have the determiner and half will lack it. Lastly,
+aa represents total absence of the determiner. Such an individual is
+_nulliplex_. He or she will not have the determiner represented in any of
+the gametes, and can not, of course, transmit a trait represented by the
+determiner.
+
+It is evident that six kinds of gametic matings are possible among
+individuals representing these various formulae. These matings are as
+follows:
+
+                                        Possible
+                                        couplings
+          Matings                      of gametes       Product
+
+  1. Nulliplex x Nulliplex (aa x aa) == a------a == all nulliplex
+                                           \/
+                                           /\
+                                        a------a
+
+  2. Nulliplex x Simplex (aa x Aa)   == a------A == 50 per cent.
+                                           \/       with character
+                                           /\       nulliplex and
+                                        a------a    50 per cent.
+                                                    with it
+                                                    simplex.
+
+  3. Nulliplex x Duplex (aa x AA)    == a------A == all with characters
+                                           \/       simplex
+                                           /\
+                                        a------A
+
+  4. Simplex x Simplex (Aa x Aa)     == A------A == 25 per cent.
+                                           \/       with characters
+                                           /\       duplex, 50 per
+                                        a------a    cent. with it
+                                                    simplex and 25
+                                                    per cent. with
+                                                    it nulliplex.
+
+  5. Simplex x Duplex (Aa x AA)     == A-------A == 50 per cent.
+                                          \/        with character
+                                          /\        duplex and 50
+                                       a-------A    per cent. with
+                                                    it simplex.
+
+  6. Duplex x Duplex (AA x AA)      == A-------A == all duplex.
+                                          \/
+                                          /\
+                                       A-------A
+
+=Indications of Incomplete Dominance.--=While in cases of strict Mendelian
+dominance it is not possible to distinguish directly the simplex from the
+duplex condition, as a matter of fact the individual of simplex
+constitution sometimes has the character represented in the single
+determiner less perfectly developed than in the corresponding character of
+duplex origin. In studying defects in man due to the absence of a
+determiner, where theoretically presence of the determiner (normality) is
+dominant over its absence in individuals of simplex constitution, one
+finds it recorded with increasing frequency that such individuals are more
+or less "intermediate" or are "tainted" with the defect; thus showing that
+the defect though obscured is not wholly in abeyance. Thus individuals
+carrying epilepsy or feeble-mindedness which are regarded as recessive
+traits, while not showing specific feeble-mindedness or epilepsy, may
+nevertheless apparently show a neuropathic taint in the form of migraine,
+alcoholism or other lapse from normality. The condition is seemingly more
+akin in some cases to that found in the offspring of certain red flowers
+crossbred with white flowers, which though red do not show the same
+intensity of color as the original red parent. Just as here the single
+determiner or single "dose" of redness is insufficient to produce the
+intensity of color that appears when the offspring receive two determiners
+for red, one from each parent, so in man a single determiner for normality
+of a specific character is inadequate in some cases to make the individual
+wholly normal. Or possibly some cases are more of the type of those in
+which the character in question, for instance the red color of some wheats
+and corn, may be produced by any one of two or three determiners, the
+intensity of the characters (red color, e. g.) depending on whether one,
+two or three determiners are present.
+
+=Why After the First Generation Only Half the Children May Show the
+Dominant Character.--=If the trait is a simple dominant one it is clear
+that it will appear in each generation and always spring from an affected
+individual. By referring back to our tabulation of possible matings on
+page 100 where the dominant character is represented by the letter A, this
+can be seen at a glance. If the trait is present in the duplex condition
+in one parent and absent from the other, then formula 3 applies; all
+children will show the trait, but in the simplex form (Aa). If the trait
+is present in the simplex form in one parent and absent in the other,
+formula 2 applies. Fifty per cent. of the children will have the character
+in the simplex form (Aa) which means also an even chance of transmitting
+it to their offspring; fifty per cent. will not inherit it and will be
+incapable, furthermore, of transmitting it, since they have become
+nulliplex (aa). In human genealogies if an individual having an unusual
+trait which is inherited as a dominant marries a normal person and half of
+the offspring show the trait (and this is common), this means that the
+parent manifesting the trait had it represented only in the simplex
+condition, otherwise all of the children would have shown it. Even though
+the original ancestor who first developed the condition or structure may
+have had it in a duplex form, it would after the first mating, if this
+were with an individual lacking the trait, be represented only in the
+simplex form (see formula 5) and could never become duplex again unless
+two individuals both having the character married, and then only in
+twenty-five per cent. of the offspring (see formula 3). If the trait is a
+defect all the children showing it, even though marrying normal
+(nulliplex) individuals, will pass it on again to half their children, but
+those who do not show it may ordinarily marry with impunity since its
+non-expression in their make-up means, as far as we know at present, that
+their germ-plasm has been purged of the defect and that they are therefore
+nulliplex with reference to it.
+
+=Eye-Color in Man.--=Of normal characters in man which follow the
+Mendelian formula perhaps eye-color is the best established. Brown or
+black eye-color is due to a _melanin_ pigment absent from the blue or gray
+eye. That is, a brown eye is practically a blue eye plus an additional
+layer of pigment on the outer surface of the iris. The different shades of
+brown and the black are due to the relative abundance of this pigment.
+Gray color and the shades of blue seem to be a modification of an original
+dark blue, due to structural differences in the fibrous tissues of the
+iris.
+
+In inheritance brown or black is dominant to blue or gray, or in other
+words the _presence_ and _absence_ of a pigment P constitutes a pair of
+allelomorphs. Hence two brown-eyed parents, if P is duplex in both (or
+duplex in one and simplex in the other) can have only brown-eyed children.
+Thus,
+
+  1. PP x PP = PP, or all duplex brown.
+
+  2. PP x Pp = PP and Pp, half duplex brown and half simplex brown.
+
+If each parent has brown eyes but in simplex condition, then one-fourth
+of children will have blue or gray eyes; for example,
+
+  Mating   Gametic              Product
+          couplings
+
+  Pp x Pp = P--P   =  PP, Pp, pP, and pp, or one-fourth
+             \/       duplex brown, one-half simplex
+             /\       brown, and one-fourth blue or
+            p--p      gray.
+
+If both parents have blue or gray eyes they can not have children with
+black or brown eyes, since the recessive condition in each parent means
+total absence of brown pigment in both.
+
+If one pair is duplex brown and the other blue, then all children will
+have brown eyes but of simplex type.
+
+If one parent has simplex brown eyes (type Pp) and one blue (pp) then
+one-half of the children will have brown eyes of simplex type and one-half
+will have blue eyes.
+
+Occasional objections have been raised against the Mendelian
+interpretation of inheritance in eye-color, but the cases cited in
+evidence against the theory usually narrow down to those in which the
+color is so diluted as to render classification uncertain. For example,
+hazel eyes are sometimes called gray; they belong however to the melanic
+pigmented type although the brown pigment may be much diluted and occur
+mainly around the pupil. So-called green eyes are due to yellow pigment on
+a blue background. In the rare cases where in the same individual one eye
+is brown and the other blue, the individual should probably be rated as
+brown-eyed on the supposition that in the one eye the development of brown
+pigment has in some way been suppressed.
+
+=Hair-Color.--=The inheritance of hair-color has also been the subject of
+considerable study and while the conditions are not so simple as in the
+case of eye-color, there is little doubt that it belongs in the Mendelian
+category. In human hair, color has as its foundation apparently two
+pigments, black and red. Absence of one or both or various combinations or
+dilutions of these seemingly account for the prevailing colors in human
+hair. In general dark hair is dominant to light, although because of the
+delay sometimes in the darkening of the hair in children this fact is
+often obscured. Black is dominant to red. People with glossy black hair,
+according to Davenport, are probably simplex for black, the glossiness
+being due usually to recessive red. The expectation would be for some of
+the children of such a pair to have red hair.
+
+In man occasionally a congenital white lock contrasting strikingly with
+the remaining normally pigmented hair occurs. It behaves as a simple
+dominant in heredity.
+
+=Hair-Shape.--=Again, straight and curly hair seem to be distinct
+inheritable characters. Curly is incompletely dominant to straight, the
+simplex condition yielding wavy hair.
+
+Not to enter into details of the matings, statistics gathered by Mr. and
+Mrs. Davenport show that, two flaxen-haired parents have flaxen-haired
+children; two golden-haired parents have only golden-haired children; two
+parents with light brown hair have children with hair of that color or
+lighter, but never darker; two parents each with dark brown or black hair
+may have children with all the varieties of hair-color. Summing together
+a series of recessives Davenport points out that two blue-eyed, flaxen or
+golden and straight-haired parents will have only children like
+themselves.
+
+
+[Illustration: FIG. 21
+
+Diagram showing descent of brachydactyly through five generations; black
+symbols indicate affected individuals; [male], male; [female], female
+(after Farabee).]
+
+
+=Irregularities.--=If a dominant trait or defect depends on more than a
+single factor, as is sometimes the case, or if it is modified by sex or
+other conditions, as is true of certain characters, some of which, such as
+color-blindness, have already been examined, then we shall find some
+apparently non-affected individuals having affected offspring. Certain
+diseases, for example, are generally transmitted by affected members of
+the family to their children in the expected Mendelian ratio for a
+dominant, yet an occasional skip of a generation may appear in which an
+apparently perfectly normal individual transmits to his children what,
+except for the omission in his own case, appears to be an ordinary
+dominant character. This occasional lapse in the appearance of a
+character when theoretically it should appear is doubtless due in some
+instances to the fact that what is really inherited is a _tendency_, and
+although this is present in the apparently normal individual, for some
+reason the condition itself has not appeared. This might especially be
+true in the case of a disease which does not manifest itself until late in
+life. In other cases there are undoubtedly complicating accessory
+conditions which modify the behavior of the trait somewhat.
+
+
+OTHER CASES OF DOMINANCE IN MAN
+
+Among other normal characters in man, as far as available evidence goes,
+dark skin is dominant to light skin; normally pigmented condition to
+albino; and nervous temperament to phlegmatic.
+
+=Digital Malformations.--=An interesting and easily followed defect is a
+condition known as _brachydactylism_, in which the digits are shortened
+because of the absence or rudimentary condition of one segment. The
+fingers, therefore, appear to be only two-jointed like the thumb. Several
+families showing this defect have been charted and it appears to behave as
+a typical dominant. In looking over such a chart (Fig. 21, p. 106) one is
+struck by the fact that only half of the children from most of the matings
+show the defect, but when we recall that the affected parent, after the
+first generation, probably carried the condition in only the simplex form
+and married a normal individual, such a result is just what would be
+expected (see formula 2).
+
+_Polydactylism_ (Figs. 22, 23, pp. 109, 110) is a condition in which there
+are extra digits on hands or feet. The character, with apparently slight
+exceptions in a few records, behaves as a typical dominant. Among other
+digital defects which are inherited as a dominant is a condition known as
+_syndactylism_ (Fig. 24, p. 111), in which two or more digits are fused
+side by side. For an example of syndactyly which seems to be in the class
+of sex-linked characters, see Fig. 15, p. 65.
+
+=Eye Defects.--=_Congenital cataract_ is another not uncommon defect in
+man which is transmitted as a dominant (Fig. 25, p. 112) with occasional
+irregularities. It is a condition of opacity of the lens of the eye which
+produces partial or total blindness. In a paper on _Hereditary Blindness
+and Its Prevention_, Clarence Loeb (1909) mentions 304 families of which
+pedigrees have been published. Of the 1,012 children in these families
+589, or 58 per cent., were affected. It is obvious that this is near the
+expected percentage in the case of a dominant trait where matings of
+affected with normal individuals prevailed. An unfortunate circumstance
+about this malady from the eugenic standpoint is the fact that it is
+frequently of the presenile form which comes on late in life so that it is
+usually impossible to predict whether an individual of marriageable age is
+immune or will later become affected.
+
+
+[Illustration: FIG. 22
+
+Radiograph (Courtesy of Dr. W. B. Helm) showing polydactyly in a child's
+hand. For genealogy of this see Fig. 23, p. 110.]
+
+
+[Illustration: FIG. 23
+
+Chart showing a history of polydactylism through five generations in the
+B---- family. The individual whose hand is pictured in Fig. 22, p. 109, is
+of the fifth generation. Squares represent males, circles females.]
+
+
+Another defect of the eye following the course of a dominant in heredity
+is a pigmentary degeneration of the retina known as _retinitis
+pigmentosa_. Atrophy of the optic nerve is also involved and the final
+result is blindness. Still another example frequently cited is that of
+hereditary night blindness (_hemeralopia_), a disease in which the
+affected person can not see by any but the brightest light. In most
+affected families the final outcome is usually total blindness. One of the
+most remarkable pedigrees of defects in man ever collected is one of this
+disease published by Nettleship. He succeeded in tracing the defect
+through nine generations, back to the seventeenth century. The genealogy
+includes 2,116 persons. The character behaves as a single dominant in
+males, but frequently, though not always, females may be carriers of the
+defect in transmissible form though not exhibiting it themselves. That is,
+males in which the condition is simplex (Aa) develop the defect but
+females of similar simplex constitution (Aa) frequently do not. It
+follows, therefore, that normal males of such strains will have normal
+offspring but normal females may have affected children.
+
+
+[Illustration: FIG. 24
+
+Radiograph (Courtesy of Dr. W. B. Helm) showing a partial syndactyly in
+each hand of an individual. Some degree of webbing between the more distal
+portions of the affected parts is usual.]
+
+
+[Illustration: FIG. 25
+
+Pedigree of a family with presenile cataract (black symbols); numbers in
+circles indicate unaffected individuals (after Davenport).]
+
+
+=Other Defects Inherited as Dominants.--=Not to go into details other
+defects which behave as dominants or modified dominants in human
+inheritance may be mentioned. The following list is not complete and it
+must be understood that in some cases the statistics are insufficient to
+justify us in making anything but a tentative decision. We may thus
+enumerate as dominant over normality: _Achondroplasy_ (abnormally short
+limbs with normal head and body); _Keratosis_ (thickening of epidermis);
+_Epidermolysis_ (excessive formation of blisters); _Hypotrichosis_
+(hairless, toothless condition); _Diabetes insipidus_; _Diabetes
+mellitus_; ordinary (not Gower's) _muscular atrophy_; _Glaucoma_ (internal
+swelling and pressure of eye-ball); displaced lens; _Coloboma_ (open
+suture in iris); spottedness of hair-coat; and corneal opacity.
+
+As a final illustration of a serious malady in man which acts as a
+dominant in inheritance, let us take _Huntington's chorea_. Ordinary
+_chorea_, or St. Vitus' dance, a disorder characterized by involuntary
+muscular movements, is commonly though not always confined to children and
+usually ends in recovery, but _Huntington's chorea_ appears typically in
+middle life and is a much more dangerous malady. Fig. 26, p. 114,
+represents the family history of one of five cases which have been studied
+by Doctor Lorenz in the Mendota Hospital for the Insane. All charts which
+have been platted of this malady show it to be inherited as a dominant.
+This means that half of the children of an individual who carried the
+malady in the simplex condition, and all the children of one who carries
+it in the duplex condition, are probably marked for this terrible end. And
+the true horror of it can only be appreciated by one who has seen the last
+stages of the malady. The victim once in its grasp gradually becomes
+wrecked in mind and body; the muscular twitchings and disorders of
+movement continually increase and dementia progresses until at last death
+ensues. Fig. 27, p. 115, is another chart showing inheritance of
+_Huntington's chorea_. In still a third case at the Mendota Hospital, the
+gravity of the situation can be appreciated when one realizes that the
+patient is the father of ten children, ranging in age from one to
+seventeen and one-half years. The calamitous fact that this disease does
+not manifest itself usually until middle life makes it likely that these
+children will all reach maturity, marry and in turn probably produce
+offspring before the doomed members of the family realize their fate.
+
+
+[Illustration: FIG. 26
+
+Chart showing descent of _Huntington's chorea_ in the P---- family
+(courtesy of Dr. W. F. Lorenz). Squares represent male, circles female;
+shaded figures are choreic members of the family; partially shaded
+figures, slightly affected or very "nervous" members. The members of the
+last generation are for the most part still too young to show their
+condition. The cross indicates the individual in the asylum from whom the
+record was traced back.]
+
+
+CASES OF RECESSIVENESS IN MAN
+
+=Recessive Conditions More Difficult to Deal With Because They Are
+Frequently Masked.--=Coming now to the question of recessive conditions in
+man, we find that defects are more likely to be of recessive than of
+dominant type. Apparently normality usually means the presence of normal
+determiners and abnormality, the absence of some essential determiner. In
+the latter case, a unit-factor has seemingly been lost out in some way in
+the germ-plasm, and the product of such germ-plasm is therefore
+incomplete. As long as the loss is counterbalanced by the presence of a
+single determiner from the other line of ancestry, that is, as long as the
+simplex (Aa) condition prevails, the loss may not be in evidence, except
+in cases of incomplete dominance (taints, etc.), but any mating which
+permits of the production of the nulliplex condition will bring the defect
+to expression again.
+
+
+[Illustration: FIG. 27
+
+Chart showing inheritance of _Huntington's chorea_ in the R---- family
+(courtesy of Dr. W. F. Lorenz); 1, 2 have been patients at Mendota
+Hospital for the Insane; 3, died of "paralysis"; the fourth or last
+generation indicated by the cross, ranging in age from 6 to 14, are too
+young yet to show their condition as regards this malady.]
+
+
+The obscure nature of recessives makes such conditions more difficult to
+deal with than dominant defects. For as regards the latter we have seen
+that marriage of unaffected members of the family as far as that
+particular trait is concerned, is perfectly safe, even to a cousin, for
+once the germ-plasm is purged of such a positive factor, it, in so far as
+we know, remains pure. But in the case of a recessive character due to the
+absence of some necessary determiner a normal offspring of simplex
+constitution (Aa) will probably transmit to half of his children the
+capacity for handing on the defect, or if mated to another normal
+individual of simplex constitution (Aa) is likely to have the actual
+defect revealed again in one-fourth of his children and latent in
+two-thirds of the remainder.
+
+=Albinism a Recessive.--=As an easily understood illustration of this type
+of case we may take human albinism, a condition which is due to the
+absence of a pigment-developing determiner. According to Davenport the
+albinic condition is recessive to normal condition. If albino (aa) is
+mated with albino (aa) nothing but albino children may be expected. An
+albino (aa) mated with a normal individual will have normal offspring
+(Aa), but they will have the capacity for transmitting albinism to their
+descendants. Thus the normal offspring (Aa) of an albino (aa) and a normal
+parent (AA) if mated to another normal individual (Aa) who has also had an
+albino parent will probably transmit actual albinism to one-fourth of his
+children and the same capacity that he himself has of producing albinos,
+to one-half of his children, although the latter will appear to the eye to
+be normal.
+
+=Other Recessive Conditions in Man.--=If for albinism we substitute
+certain forms of insanity, hereditary feeble-mindedness (Fig. 28, p. 118),
+or hereditary epilepsy, all of which apparently follow the same law, we
+can readily understand how unfit such matings are where both strains are
+affected. Marriage with similarly defective stock will result in the
+affection appearing in one-fourth of the progeny, and one-half of them,
+though apparently normal themselves, will have the capacity for
+transmitting the imperfection. It is in the existence of such hidden
+factors that the chief danger in the marriage of cousins, or in fact any
+consanguineous marriage lies.
+
+A few of the various defects which seem to be inherited as recessives when
+mated with normality are: susceptibility to cancer; _chorea_ (St. Vitus'
+dance); true dwarfism (all parts proportionately reduced); _Alkaptonuria_
+(urine darkens after passage); alcoholism and criminality, where based on
+mental deficiency; hereditary _hysteria_; _multiple sclerosis_ (diffuse
+degeneration of nervous tissue); _Friedreich's disease_ (degeneration of
+upper part of the spinal cord); _Merriere's disease_ (dizziness and
+roaring in ears); _Thomsen's disease_ (lack of muscular tone); hereditary
+_ataxia_; possibly the tendency to become hard of hearing with increased
+age; and possibly, non-resistance to tuberculosis.
+
+Of non-pathological conditions in man which are inherited as recessives,
+apparently either very great or very small intellectual ability are
+examples.
+
+
+[Illustration: FIG. 28
+
+Chart showing descent of feeble-mindedness as a typical recessive (after
+Goddard). Squares represent males, circles females; DD, homozygous
+dominant; DR, heterozygous dominant (i. e. normal although a carrier); RR,
+pure recessive; N, normal; F, feeble-minded; A, alcoholic.]
+
+
+=Breeding Out Defects.--=Even though recessive defects occur in a stock,
+there is the possibility of diluting out the imperfection in successive
+generations if care is taken always to marry into a stock wholly free from
+it. For example, a normal individual carrying a recessive defect will bear
+the abnormality in half of his or her germ-cells. This means that when
+such an individual marries a normal, non-carrier, half of their children
+will be wholly normal (AA) and half will be carriers; normal but of
+simplex constitution (Aa). If now this generation, carriers and
+non-carriers, marry only into normal strains of duplex constitution, then
+their combined issue will be likewise normal with only one-fourth of them
+carriers of the imperfections. This means that even if all of this last
+generation were married to persons having the defect only one out of four
+would have children showing it although the remaining children would be
+carriers. On the other hand if mated to normals only one-eight of the next
+generation would be carriers. Thus by continually marrying into strong
+strains liability to manifest any recessive defect can be diminished in a
+few generations until the descendants are no more likely to have defective
+children than are members of our ordinary population.
+
+The proportion in which the recessive defect would appear in successive
+generations if all persons in a given generation married only normal
+individuals who were non-carriers is indicated in the following table
+where AA indicates a normal individual, Aa one who is normal but a
+carrier, and aa an individual with the imperfection expressed; to indicate
+proportions simply after the first generation, four is arbitrarily chosen
+as the number of children which results from each marriage:
+
+                  Matings   Children
+  Generation 1    aa x AA = Aa
+
+  Generation 2    Aa x AA = 2AA + 2Aa
+
+  Generation 3    AA x AA = 4AA
+                  AA x AA = 4AA
+                  Aa x AA = 2AA + 2Aa
+                  Aa x AA = 2AA + 2Aa
+                           ----------
+                           12AA + 4Aa
+
+=Other Inheritable Conditions in Man.--=While many pedigrees show beyond
+dispute that such qualities as musical ability, literary ability, memory,
+calculating ability, mechanical skill, longevity, peculiarities of
+handwriting, obesity and muscular strength, for example, are inherited,
+their modes of inheritance have not yet been sufficiently analyzed to
+express them exactly.
+
+
+
+
+CHAPTER V
+
+ARE MODIFICATIONS ACQUIRED DIRECTLY BY THE BODY INHERITED?
+
+
+=Which New Characters Are Inherited?--=Any new feature which appears in a
+given organism may have had its origin in some change which has come about
+in the germ from which it sprang, or it may be merely the product of some
+unusual stimulus operating on the body. While the outcome, as far as the
+present individual is concerned, is in each case a definite modification,
+the matter of inheritance is a very different question. On the first
+alternative where the new character is the outcome of germinal change, it
+is obvious that the altered germ-plasm will find expression in a similar
+way in succeeding generations as long as the new germinal combinations
+persist. On the other hand, if the new character has resulted merely from
+some influence operating on the body of the individual, then to be
+inherited it would also have in some way to be transferred to and
+incorporated in the germ-plasm. Inasmuch as the body or soma of any
+individual is highly plastic and since various of its ultimate features
+may be mere somatic modifications, it is important to decide if possible
+whether or not somatic variations which are not of germinal origin can be
+inherited.
+
+=Examples of Somatic Modifications.--=For example, the small foot of the
+Chinese woman of certain caste is the result of inherent germinal factor
+for the production of a foot plus the effects of binding which are in no
+wise germinal. The hand of the skilled pianist is a normal hand of
+germinal origin and normal environment plus the effects of special
+training. Again, the head of the Flathead Indian is a normal head of
+germinal origin and environment plus the effects of flattening. Similarly,
+almost any malformation of extrinsic origin may be cited, ranging from
+mutilations and amputations, scars and the like to monstrosities such as
+one-eyed fish which may be produced by subjecting a developing embryo to
+adverse conditions of development.
+
+=Use and Disuse.--=Even reactions set up through the organism's own
+activities must produce changes. For example, a muscle has a certain
+average of normal development in the average man; it comes to this through
+the innate nature of its component cells plus a certain average amount of
+exercise. It may, however, be developed far beyond this average by
+excessive exercise. On the other hand, it is a well-known fact that an
+unused organ weakens or may remain but partially developed. Thus either
+use or disuse may play an important part in the molding of a given
+individual. But whether or not in doing this it similarly affects the germ
+is a very different matter.
+
+=The Problem Stated.--=The question is can such enhanced or suppressed
+development, or can new or modified characters, produced in an individual
+by external agencies be so reflected on the germ-cell of the individual
+that they tend to reappear _as such_ in its offspring without requiring
+the same external factors for their production?
+
+=Special Conditions Prevail in Mammals.--=Before proceeding further we
+must recognize clearly the very special conditions which exist in most
+mammals. With them environment is in part an intra-maternal environment
+and in part independent of parental influences. Thus the formula for most
+non-mammalia would be--
+
+  Individual == egg + non-parental environment; but
+
+for most mammals, including man--
+
+  Individual == egg + intra-maternal environment + non-parental
+  environment.
+
+This condition in mammals introduces a complicating factor which is likely
+to obscure the whole issue unless we bear it constantly in mind. In other
+words, we must discriminate sharply, in the discussion of inheritance in
+man, for instance, between two classes of influences which may exist in
+the infant at birth, that is, which are _congenital_; namely, those which
+were truly inherent--were in the germ-cells--at the very inception of the
+young individual, and (2) those which might later have been derived from
+either parent by the yet unborn offspring. The latter are not regarded as
+truly hereditary. Since certain diseases or their effects belong here we
+occasionally find a physician using the term inheritance for such prenatal
+influences, but the more careful ones now employ the term _transmission_
+to discriminate between such conditions and true inheritance. In its
+biological usage inheritance always refers to germinal constitution and
+never to any condition that may be thrust on a developing organism before
+birth. It is clear, then, that congenital conditions are not all
+necessarily cases of inheritance.
+
+=Three Fundamental Questions.--=To get at the question of the inheritance
+of body modifications with the least confusion, let us examine it in the
+form of three fundamental questions, as follows:
+
+1. Can external influences directly affect the germ-cells?
+
+2. Can external influences, operating through the intermediation of the
+parental body, affect the germ-cells? If so, is the effect a specific and
+a permanent one which persists in succeeding generations independently of
+external influences similar to those which originally produced it? Only
+such a condition as this would rank as the inheritance of a somatic
+modification.
+
+3. Can the appearance of new characters be explained on any other ground,
+or on any more inclusive basis, than through the transmission of somatic
+acquirements, or do organisms possess heritable characters which are
+inexplicable as inheritance of such modifications?
+
+Obviously the only way the question can be settled is through careful
+experimentation in which all possible sources of error have been foreseen
+and guarded against. Much experimental work has been undertaken for the
+solution of this problem as the goal and we may therefore select typical
+ones of these experiments and apply the results toward answering our three
+questions.
+
+=External Influences May Directly Affect the Germ-Cells.--=There is
+evidence that under special conditions external influences may in certain
+organisms affect the germ-cells, but that this occurs commonly is
+extremely doubtful. For example, Professor MacDougal, by treating the
+germ-cells of the evening primrose with various solutions, such as sugar,
+zinc sulphate and calcium nitrate, has apparently succeeded in producing
+definite germinal mutations. He injected the solution into the ovary of
+the flower the forenoon of the day at the close of which pollination would
+occur. He reports that in this way changes were produced in the germ which
+found expression in new and permanent characters.
+
+Professor Tower has experimented for a number of years with various
+species of _Leptinotarsa_, the potato beetle. By varying the conditions of
+temperature, humidity and atmospheric pressure when females were laying
+their eggs, he reports having produced variations in the young which came
+from these eggs although the mothers themselves were not changed.
+According to Professor Tower slight increase or decrease in these
+environmental factors stimulated the activity of the color producing
+ferments, giving rise to melanic or darker individuals. Greater increase
+or decrease, inhibited them and produced albinos. He found also that at
+times the same stimulus might show different results in different eggs.
+The effect, therefore, is a general and not a specific one. Ordinarily the
+eggs of these beetles are laid in batches. When one of these batches was
+laid and left under normal conditions, the usual form of young hatched
+from it, but other batches from the same female under abnormal conditions
+resulted in the production of atypical forms. For example, a normal
+two-brooded form became five-brooded. The commonest modification was the
+production of various color types. These once established, according to
+Professor Tower, behave as independent, inheritable units.
+
+The experiments of Doctor Bardeen with X-rays and of others with X-rays,
+radium and other agents on the sperm and ova of amphibia show that these
+are very susceptible to injurious influence at or near the time of
+fertilization.
+
+=Such Effects Improbable in Warm-Blooded Animals.--=However possible it
+may be to bring about germinal changes in invertebrata or lower vertebrata
+by such external agents as temperature and the like it is obvious that the
+probability of such extrinsic influences affecting the germ-cells of
+warm-blooded animals is very remote indeed. In the latter the germ-cells
+are more or less distant from the exterior and are at practically a
+constant temperature. Such experiments, therefore, beyond showing the
+possibility of producing changes in germ-cells, do not have very direct
+bearing on the problem of how inheritable variations are produced in man.
+In his case about the only avenue of approach through which germ-cells
+might be influenced is the blood or lymph.
+
+=Poisons in the Blood May Affect the Germ-Cells.--=Any poisonous material
+in the latter might injuriously affect the gametes. We know, in fact, that
+such poisons as alcohol, lead and various drugs, and also the toxins of
+various diseases, do so affect germ-cells. It seems plausible to suppose
+that changing conditions of nutrition may affect the constitution of the
+germ-cells and thus induce changes in the organism which arise from these
+cells, but such nutritional effect is not yet a matter of established
+fact.
+
+=Difficulty of Explaining How Somatic Modifications Could be Registered in
+Germ-Cells.--=As to our second query concerning the possibility of
+affecting the germ-cells through the intermediation of parental tissues,
+it is evident at a glance that since the germ-cells are built up along
+with the body and are not a product of it (Fig. 2, p. 13), if such effects
+are possible they must take place through the agency of some transporting
+medium. The germ-cells, being lineal descendants of the original fertile
+germ or zygote, already have the same possibilities of developing into an
+adult that the zygote had, and so the problem becomes one of modifying a
+complete germ already organized rather than of establishing a new germ by
+getting together samples of every part of the body. This is all the more
+evident when one realizes that usually the germ-cells are set apart long
+before the body becomes adult, that is, before the body has developed most
+of its characteristics. Moreover, among lower animals many instances are
+known where the immature young or even larvae will produce offspring which
+nevertheless ultimately manifest all the structures of the adult
+condition.
+
+But supposing specific modifications of the germinal mechanism were
+possible, it is difficult to comprehend how an influence at a distant
+point of the body could reach the germ-cell, to say nothing of the even
+greater difficulty of understanding how it could become registered in the
+germ in a specific way as affecting a particular part. For it must be
+remembered that the organs of the adult do not exist as such in the germ
+but are present there only as potentialities. How, for example, can a
+change in the biceps muscle of one's arm be registered in a germ-cell in
+which there is no biceps muscle, but merely the possibilities of
+developing one? Or how can increased mental ability which is contingent on
+the elaboration of certain brain-cells be impressed on a germ which has no
+brain-cells but only the capacity under certain conditions of producing
+such cells? For the brain of a child is not descended from the brain of
+his parent, but from a germ-cell carried by that parent.
+
+=Persistence of Mendelian Factors Argues Against Such a Mode of
+Inheritance.--=On the face of things, the apparent inviolability of
+Mendelian factors which may remain unexpressed in the germ for one or many
+generations--indeed the whole matter of genotypical differences in the
+gametes of the same individual--shows the improbability of somatic
+interference with the germ-plasm. But notwithstanding this, because of the
+great importance of the issue, it is well to review in some considerable
+detail the various phases and possibilities of the question.
+
+=Experiments on Insects.--=Some of the attempts to secure evidence of the
+transmission of personally acquired parental modifications in insects are
+very interesting. Many insects in the larval stages, particularly just
+after pupation seem to be especially susceptible to external influences.
+They have been much used, therefore, for purposes of experiment. It has
+long been known that differences in size, in color and even in the shape
+of wings can be produced by various agents if applied at this period of
+development. From the standpoint of heredity, however, the important
+consideration is to determine if these experimentally induced changes have
+been reflected on to the germ-cells so that they reappear in the offspring
+of the modified individuals.
+
+It has been found that in some cases where male and female are of
+different color, the color of the female can be changed to that of the
+male by altering the conditions of temperature. In certain cases types can
+be changed by cold so that they resemble varieties of the same species
+found farther north, and by heat, varieties found farther south. But not
+all individuals of a given lot are affected, and often different
+individuals of the same kind show different effects. Moreover, in some
+cases the same aberrations were produced by heat as by cold. This
+indicates that it is not so much a question of specific effects as a
+general physiological change, apparently mainly a matter of direct
+influence of temperature on the chemical composition of the pigments. The
+Countess von Linden in fact has shown that the extracted pigments can be
+made to undergo the same changes of color in a test-tube by heat and cold
+as in the pupae. But there is no evidence that the germ-cells of the living
+insect were affected in a specific way. In a small fraction of the
+offspring of such modified individuals abnormalities appeared, but these
+were not always of the same kind as those which had been produced in the
+parent. That is, there was no evidence of a trait or character having been
+acquired by the body and handed on to the germ-cell. Where an effect was
+produced on the germ-cell it was probably produced directly as in the
+first cases discussed.
+
+Size, colors and markings of butterflies have also been altered by
+subjecting the caterpillars or the pupae to such influences as strong
+light, electricity, various chemical substances, centrifuging, diminished
+oxygen supply, etc., but the results were in the main confined to the
+immediate generations. In the few cases where permanent inheritable
+changes were seemingly produced they were more reasonably interpreted as
+the effects of direct action on the germ-cells than as examples of
+inherited somatic modifications.
+
+Starvation experiments which resulted in the dwarfing of adult individuals
+have been performed on various insects, and while the dwarf condition may
+persist through one or two generations due to a diminished food supply in
+the eggs of the dwarf, the stock in question when returned to normal food
+conditions soon resumes its original characteristic size.
+
+=Experiments on Plants.--=Many experiments have been performed with
+plants, inasmuch as they are particularly prone to become modified by
+changes of food supply, or climate. For example, plants which grow
+luxuriantly in a warm moist climate or a rich soil may become stunted and
+markedly changed if transplanted to a cold climate or a poor soil.
+Naturally, their progeny will exhibit the same behavior as long as they
+are kept under the new conditions. Experiments carried on through numerous
+generations, however, practically all show that the germinal constitution
+of the plants remains unchanged, for when their seeds are planted under
+the original favorable conditions of soil or climate, the plants resume
+their former habits of growth. Naegeli, for instance, who made a study of
+many varieties of Alpine plants, and who carried on experiments with many
+of them for years in the Garden of Munich, concluded that no permanent
+effects had been produced by the Alpine climate and conditions in plants
+from other regions which had come under its influence. A few botanists
+have claimed to have found that the changes produced by the Alpine climate
+have persisted for a generation or two and have then worn off. More recent
+experiments on various of our field grains which have been stunted and cut
+down in productivity by growing for a number of generations under adverse
+conditions show that they have not been permanently modified by such
+treatment, for they resume normal productivity and size when grown again
+under favorable conditions.
+
+On the other hand, Lederbaur found that a common weed, _Capsella_, when
+transplanted from an Alpine habitat to the lowlands did not return to the
+lowland type of the weed, but retained certain of its Alpine
+characteristics. It is not clear, however, that this particular species
+during its long sojourn of many generations in Alpine conditions may not
+have undergone a series of germinal variations and have developed into a
+new variety or species quite independently of changes wrought in the germ
+by reflected somatic effects. Indeed, in face of the preponderance of
+other cases to the contrary, this interpretation would seem to be the more
+plausible one.
+
+=Experiments on Vertebrates.--=In the vertebrates we may also find
+examples of various somatic modifications experimentally produced, but
+evidence of their inheritance is as difficult to establish as in the
+invertebrates. Let us examine a few of the more significant of these which
+are alleged by some to bear evidence of such inheritance.
+
+By decreasing the amount of water in an aquarium Marie von Chauvin was
+able to transform the aquatic, gill-breathing salamander _Axolotl_ into
+the gill-less land form _Ambystoma_, heretofore regarded by systematists
+as a different species. Either of these forms when sexually mature
+produces its like. The salamanders in question have both lungs and gills,
+but after a time the ones which are to be land forms lose their gills and
+become exclusively lung-breathers. What seems to have been accomplished
+then is the accelerating or forcing of normal natural tendencies already
+inherent in the organism instead of introducing something new into the
+inheritance by way of the soma. _Axolotl_ is in all probability merely a
+larval form of _Ambystoma_ which with high temperature and an abundance of
+water reproduces without advancing to the final possible stage of its life
+cycle.
+
+=Epilepsy in Guinea-Pigs.--=Perhaps the most frequently cited case and the
+one in which the defenders of the idea of somatic inheritance usually take
+final refuge is that of Doctor Brown-Sequard's guinea-pigs,
+notwithstanding the fact that no one has had convincing success in
+repeating the experiments and that the original results are apparently
+open to more than one interpretation. This experimenter rendered
+guinea-pigs epileptic by certain injuries to the nervous system. Epilepsy
+appeared in some of the offspring of these operated animals. He regarded
+this as an example of the inheritance of an artificially induced epilepsy.
+An indirect loss of toes occurred in some of the parents as a result of
+the operations on the nervous system. Some of their young also had missing
+toes. However, as has been pointed out by various critics, guinea-pigs are
+strongly predisposed toward epileptic-like seizures, and the epilepsy in
+the young may have been merely a coincidence. Voison and Peron believe
+they have shown that in epilepsy a toxin is produced that may affect the
+unborn fetus. That is, the result might have been due to a poison derived
+directly from the mother. The experiments in fact show that it was mainly
+in the offspring of affected mothers that the condition appeared. Others
+maintain that we do not know the exact nature of epilepsy, that in some
+cases it may be the result of infection by disease-germs, and that
+Brown-Sequard's cases may, therefore, have been merely the communication
+of a disease from parent to child. As to the disappearance of toes it is a
+well-known fact that rodents in particular are likely to gnaw off the toes
+of their young very soon after birth, and little credence can be put in a
+lack of toes in such young as cases of inheritance except under conditions
+of much more careful observation than existed in Brown-Sequard's
+experiments. A fuller account of these experiments will be found in
+Romanes' _Darwin and After Darwin_, Vol. II, Chap. 6.
+
+=Effects of Mutilations Not Inherited.--=Many experiments have been
+performed by investigators to determine whether or not the results of
+mutilation are transferred to succeeding generations, but so far only with
+negative results. Many such experiments have been unwittingly carried on
+for many generations, in fact, by breeders and fanciers, in the docking of
+horses, dogs and sheep, the dehorning of cattle and the like, yet no
+satisfactory evidence of the transmission of such conditions in any degree
+has ever been forthcoming. The mutilations or distortions of the human
+body through various rites or social customs also fails to yield any
+convincing examples. Foot-binding, head-binding, or waist-binding must be
+repeated in each successive generation to produce the particular type of
+"beauty" that results from such deformities. And lucky it is for man that
+injuries do not persist in subsequent generations, otherwise the modern
+human being would be but a maimed relic of past misfortunes.
+
+=Transplantation of Gonads.--=An interesting experimental test regarding
+the effect of the body on the germ was made recently by Castle and
+Phillips with guinea-pigs. It will be recalled from the discussion on
+Mendelism that when a black guinea-pig is mated with a white one the
+offspring are always black. These experimenters transplanted the ovaries
+from a young black guinea-pig to a young white female whose own ovaries
+had been previously removed. This white female was later mated to a white
+male. Although she produced three different litters of young, six
+individuals in all, the latter were all black. That is, not a trace of
+coat-color of the white father or of the white foster-mother was impressed
+on the transplanted germ-cells or the developing young. Later experiments
+of the same kind by Castle and Phillips, with other varieties of
+guinea-pigs, have yielded the same results. The body of the mother,
+indeed, seems to serve merely as a protective envelope and a source of
+nutrition.
+
+=Effects of Body on Germ-Cells General, Not Specific.--=As far as the
+evidence regarding the modification of the germ-plasm by the body is
+concerned, we must conclude then that while under special circumstances
+the germ-cells may be affected, the effect is general rather than specific
+and the result as seen in the offspring has no discoverable correlation
+with any particular part or structure of the parental soma. The effect is
+presumably of much the same nature as where the germ is directly affected
+by external agents. Where a new character or a modification of one already
+existing is produced by a given condition of environment, in our
+experience so far to have the same repeated in the offspring, a similar
+evocative condition must prevail in the environment of the latter. Or in
+other words the new character is not a permanent one which persists in
+succeeding generations independently of external influences similar to
+those which originally produced it.
+
+=Certain Characters Inexplicable as Inherited Somatic Acquirements.--=It
+would require remarkable credulity, in fact, to believe that some of the
+most striking features about certain plants or animals could have been
+developed by means of the inheritance of somatic modifications. For
+example, many animals such as the quail, the rabbit, or the leaf-butterfly
+are protectively colored. That is, they harmonize in color-pattern with
+their surroundings so closely that they are overlooked by their enemies.
+But how can this oversight on the part of an enemy so affect the bodies
+and through them the germ-cells of such individuals as to develop so high
+a degree of protective coloration? Or how, indeed, could any of numerous
+adaptive structures which one can think of, such as the color or scent of
+flowers to lure insects for cross-pollenation, the various grappling
+devices on many seeds to secure wide distribution by animals, or the like,
+have been directly produced by use or disuse or by any variation produced
+in them by the agents to which they are adapted?
+
+=The Case of Neuter Insects.--=A very instructive example of the
+improbability that great skill, highly specialized structures, or certain
+instincts are first developed in the parental body as the result of use
+and then passed on to the offspring, is seen in the case of neuter
+insects. In bees, for example, there are three classes of individuals: the
+drones or males; the queens or functional females; and the workers, which
+are neuter, that is, take no part in reproduction. The latter are really
+sexually undeveloped females. The queen can lay either fertilized or
+unfertilized eggs. The latter always give rise to males. The workers
+gather the food, attend the queen, wait on the young, construct the comb,
+and in short perform all the ordinary functions of the colony except the
+reproductive. They have many highly specialized structures on various
+parts of their bodies for carrying on their many activities, as well as
+the very highly specialized instincts necessary to the maintenance of the
+colony. But now, complex and highly developed as these workers are, since
+they do not give rise to offspring, no matter how much experience or
+structural modifications they may acquire during their lifetime, it can
+not be handed on to another generation. Nor can they have come to their
+present highly organized state through such a form of transmission since
+they are not the descendants of workers but of a queen. Any new
+modifications that appear in the workers of a colony must therefore have
+their origin in changes which have taken place in the germ-cells of the
+queen, and not in the soma of some other worker. It has been argued that
+the worker has not always been infertile; that at a more primitive stage
+of the evolution of the bee colony every female was both worker and
+mother, and that individual somatic acquirements might therefore have been
+transmitted, but this argument can not hold for many of the instincts or
+features of the modern bee because these have to do only with the
+conditions of life which exist in the colony in its present form. It is
+obviously absurd to maintain, for instance, that all the highly
+specialized instincts incident to queen production, queen attendance and
+the like were functionally produced through usage before there was any
+queen to produce or attend, while on the other hand, the very necessity of
+queen production and maintenance is the outcome of the infertility of the
+workers. Some workers have been known to lay eggs, but as these are few in
+number and are never fertilized, which means if they develop they can only
+produce males, they can play no considerable part in inheritance.
+
+
+ORIGIN OF NEW CHARACTERS
+
+=Origin of New Characters in Germinal Variation.--=This brings us to our
+last query as to whether the appearance of new characters can be explained
+on any other or any more inclusive ground than that which infers that
+changes undergone by the parent-body are in some way registered in the
+germ-cells so as to be repeated in a certain measure in the body of the
+offspring. The answer to the question of how inheritable variations do
+come to appear in offspring if not through changes produced in the body of
+the parent, is uncertain; nevertheless most biologists believe that they
+do not have such a somatic origin but arise directly as germinal
+variations. Some would attribute them to the fluctuating nature of living
+substance in general. The instability of protoplasm is one of its striking
+characteristics. It is constantly being broken down and built up, or, in
+other words, undergoing waste and repair. Like all other protoplasm, that
+of the germ-cells must also undergo these metabolic changes and it is
+possible though not proved that in this give and take of substances small
+changes occur in their constitution which find expression in the offspring
+as variations. As already seen, substances in the blood other than food
+may also affect the constitution of the germ-cells.
+
+=Sexual Reproduction in Relation to New Characters.--=Some biologists
+attribute great importance to sexual reproduction as a basis of variation
+and the origin of new characters. They argue that the mingling of
+determiners from two different lines must produce many new combinations
+and expressions of germinal potentialities. Plausible as the argument
+seems at first sight no one has succeeded as yet in securing proof that
+absolutely new characters can be originated in this way. What seems to
+occur under such circumstances is merely a reshuffling or sorting of old
+unit-characters. Although innumerable permutations and combinations of
+these may be made which find new expression outwardly, this is obviously
+not creating determiners of new unit-characters in the germ-plasm. While
+many biologists would not deny the possibility or even the probability
+that the determiners of unit-characters may sometimes combine or influence
+one another so as to form actual permanent new characters, the proof of
+such performance is wholly lacking. On the other hand, there are not a few
+biologists who argue that sexual reproduction accomplishes just the
+reverse of increasing the extent of variation or creating new characters;
+according to them it tends to annul exceptional peculiarities of either
+parent by throwing the offspring back to the average racial type. It is
+thus looked on by these advocates as a stabilizer which reduces the
+amplitude of variations instead of increasing them. As a matter of fact
+the two ideas are not mutually exclusive; sexual reproduction may
+accomplish both of these ends. A limited number of observations and
+experiments have been made to test out the correlation between sexual
+reproduction and variation, but they have so far been too few or too
+inconclusive to enable us to come to a satisfactory conclusion.
+
+While we are uncertain about the method of origin of new characters the
+fact remains that they do arise in abundance as abrupt mutations or
+otherwise and become a part of the permanent heritage of a stock. It is
+clear that sexual reproduction may be one important means by which a given
+new character which has arisen in one or a few individuals may become
+incorporated in the species at large. Through Mendelian combinations and
+segregations it would by cross-breeding be spread and gradually introduced
+into more and more strains of the general population.
+
+=Why So Many Features of an Organism Are Characterized by
+Utility.--=Germinal variations are seemingly at first more or less hit or
+miss affairs as far as utility to the organism is concerned. Useless
+variations, so long as they are not actually harmful, may persist and
+apparently be indefinitely inherited. However, a special premium is put on
+variations which happen to be useful for they help the organism to succeed
+in its struggle for life and since success in the world of life means not
+only mere individual survival but also the production of progeny, through
+this very means insured transmission to subsequent generations. It is
+probable that the very many useful features of any organism, that is, its
+_adaptations_, have thus been established. It is possible also that many
+variations which at their inception are indifferent may wax in strength in
+successive generations until they reach a point where they must become
+either useful or harmful. In the former case they would mean increased
+insurance of survival for their possessors, in the latter, elimination.
+With such an automatic process as this operative in nature it is not
+astonishing that the main features of any organism are characterized by
+their utility to it.
+
+=Germinal Variation a Simpler and More Inclusive Explanation.--=The gist
+of the whole matter regarding the source of new characters in offspring
+seems to be that the explanation based on the idea of germinal variation
+is in last analysis the simpler and more inclusive, and there is no
+alleged case of inheritance of parental modification, which can not be
+equally well explained as the result of a germinal variation. There are
+numerous cases which can not be explained as transmissions of somatic
+acquirements even if this transmission could be established in certain
+cases. So, many biologists argue, why have two explanations when one is
+sufficient, especially when the other has never been conclusively
+established as true in any case and is obviously untrue in certain test
+cases? The attitude of most investigators is that of the open mind. While
+feeling that the weight of probability is very decidedly against the
+theory of the inheritance of somatic modifications, they still stand ready
+and willing to accept any evidence in its favor which when weighed in the
+balance is not found wanting.
+
+
+ANALYSIS OF CASES
+
+While space will not permit extended discussion, in order further to fix
+the nature of the problem in mind as well as to exemplify the conditions
+that must be satisfied to form convincing evidence of inherited somatic
+acquirements, it will be well perhaps to analyze a few typical cases as
+they are frequently cited.
+
+=Are the Effects of Training Inherited?--=Breeders and trainers very
+commonly believe that the offspring of trained animals inherit in some
+measure the effects of the training. Thus the increased speed of the
+American trotting horse is often pointed to as strong evidence of such
+transmission. According to W. H. Brewer, the earliest authentic record of
+a mile in three minutes was made in 1818. The improvement, approximately
+by decades, from that time was as follows:
+
+  During 1st decade after 1818, improved to 2:34
+         2nd   "      "    "       "     "  2:31-1/2
+         3rd   "      "    "       "     "  2:29-1/2
+         4th   "      "    "       "     "  2:24-1/2
+         5th   "      "    "       "     "  2:17-1/2
+         6th   "      "    "       "     "  2:13-1/2
+         7th   "      "    "       "     "  2:08-1/2
+
+By 1892, the date of Professor Brewer's publications (See _Agricultural
+Science_, Vol. 4, 1892) the record had reached 2:08-1/2. Since then it has
+been lowered still further.
+
+On the face of it this looks like a good case of inheritance of training,
+and Brewer himself believed it such. If so this would mean that colts of a
+highly trained trotter would be faster than they would have been if their
+parent had remained untrained. It is impossible to get positive proof in
+the case of any trained horse since there is no way of establishing just
+how speedy the progeny would have been had the parent remained untrained.
+If it could be shown that colts sired by a trotter late in life were on
+the whole faster than those sired by the same father when younger and as
+yet not highly exercised in trotting, then the facts might give some
+evidence of value, but unfortunately no such records are available.
+
+On the other hand, even ignoring the fact that improvement in track and
+sulky are probably the biggest items in the shortening of records in
+recent times, _selection_ instead of inheritance of the effects of
+training will equally well account for any innate progress in trotting.
+And since, as pointed out by Professor Ritter, there are even more
+striking cases of similar improvements in other fields, such as college
+athletics, where the factor of use-inheritance is entirely precluded, it
+is wholly unnecessary to postulate it in the case of the trotter.
+
+For example an inspection of the records of college athletics for the last
+thirty-five years in running, hurdling, pole-vaulting, jumping, putting
+the shot, etc., shows on the whole a steady advance year by year.
+Moreover, the greatest improvement has occurred in those events in which
+skill and practise count for most together with selection of the
+inherently ablest candidate for the events. But in the case of athletics
+the improvements shown in thirty-five years have all come within a single
+generation and hence the inheritance of the effects of training is ruled
+out as a factor. Selection and improved training are the only factors
+operative.
+
+In the case of the trotter inheritance undoubtedly has also been a factor,
+but inheritance based on selection of what the race-track has shown to be
+the speediest individual, not inheritance of the effects of training. In
+other words, horses which have shown the capacity for being trained to the
+highest degree of speed have naturally been selected as sires and dams
+and so through selection generation after generation a speedier strain has
+gradually been established.
+
+=Instincts.--=When we turn to the realm of mental traits, particularly of
+instincts, we meet with a whole host of activities which are frequently
+pointed to by transmissionists as examples of inherited acquirements. Thus
+according to them, habits at first acquired through special effort
+ultimately become instinctive, or according to some, instinct is "lapsed
+intelligence." Instances often cited are the pointing of the bird-dog, the
+extraordinary crop-inflation of the pouter-pigeon, or the tumbling of the
+tumbler pigeon. We can not stop to discuss these cases beyond pointing out
+as many others have done that practically all dogs have more or less of an
+impulse to halt suddenly, crouch slightly and lift up one fore-foot when
+they scent danger or prey, that all pigeons pout more or less, and that
+practically all show more or less instincts of tumbling when pursued by a
+hawk. Thus in all of these cases the fundamental germinal tendency is
+already at hand for the fancier to base his choice on and thus through
+selection build up the type desired. Just as in the fan-tailed pigeon, by
+repeatedly selecting for breeding purposes individuals which showed an
+unusual number of tail-feathers he has built up a type with an upright,
+fan-like tail having many more feathers than the twelve found in the tail
+of the ordinary pigeon, so by similar procedure in the case of other forms
+he has markedly enhanced certain features. The idea of instincts being
+"lapsed intelligence" is so clearly and concisely criticized in an
+article by the late Professor Whitman[4] that I can not do better than
+quote an excerpt. His views to the contrary are as follows:
+
+    "The view here taken places the primary roots of instinct in the
+    constitutional activities of protoplasm and regards instinct in every
+    stage of its evolution as action depending essentially upon
+    organization. It places instinct before intelligence in order of
+    development, and is thus in accord with the broad facts of the present
+    distribution and relations of instinct and intelligence, instinct
+    becoming more general as we descend the scale, while intelligence
+    emerges to view more and more as we ascend to the higher orders of
+    animal life. It relieves us of the great inconsistencies involved in
+    the theory of instinct as "lapsed intelligence." Instincts are
+    universal among animals, and that can not be said of intelligence. It
+    ill accords with any theory of evolution, or with known facts, to make
+    instinct depend upon intelligence for its origin; for if that were so,
+    we should expect to find the lowest animals free from instinct and
+    possessed of pure intelligence. In the higher forms we should expect
+    to see intelligence lapsing more and more into pure instinct. As a
+    matter of fact, we see nothing of the kind. The lowest forms act by
+    instinct so exclusively that we fail to get decided evidence of
+    intelligence. In higher forms not a single case of intelligence
+    lapsing into instinct is known. In forms that give indubitable
+    evidence of intelligence we do not see conscious reflection
+    crystallizing into instinct, but we do find instinct coming more and
+    more under the sway of intelligence. In the human race instinctive
+    actions characterize the life of the savage, while they fall more and
+    more into the background in the more intellectual races."
+
+For further discussion of this field the reader is referred to an
+excellent chapter on "Are Acquired Habits Inherited?" in C. Lloyd Morgan's
+book, _Habit and Instinct_.
+
+=Disease.--=Perhaps in the realm of disease more than in any other has an
+interest in the inheritance of somatic acquirements been manifested. The
+problem arising here is not essentially different from other questions of
+inheritance but since it is a matter of such practical importance to man,
+we may well give it special attention. We have to deal simply with the old
+questions of what is constitutionally in the germ, what is acquired by the
+body, and lastly, whether the somatically acquired is inherited. While we
+all know in a general way what is meant by disease, especially if some
+specific disorder such as scarlet fever, malaria or tuberculosis is
+mentioned, an attempt to give an accurate definition is much like trying
+to define a weed, inasmuch as what is functionally all right at one time
+or place may be all wrong at another, or what is normal in one animal may
+be abnormal in another. In general we may say that disease is derangement
+or failure of physiological function.
+
+=Reappearance of a Disorder in Successive Generations Not Necessarily
+Inheritance.--=In attempting to study the inheritance of diseases we must
+recognize clearly at the outset that reappearance of a disease in
+successive generations by no means necessarily signifies inheritance.
+Before it can be pronounced such we must make sure that it is not a case
+of reimpressing similar modifications on the individuals of successive
+generations. For example, in England there is a well-recognized condition
+known as collier's lung which results from constant working in coal mines.
+And while both father and son may exhibit it, because of their similar
+occupations, there is nothing hereditary about the malady. Likewise there
+is what is known as emery grinder's lung, and practically every large
+manufacturing city with soot-laden atmosphere leaves its impress on the
+lungs of the inhabitants. This will occur, of course, generation after
+generation, as long as such pollutions of the atmosphere continue to
+exist. It is clear that any unhealthy occupation is likely to cause the
+reappearance of an associated typical disease generation after generation
+as long as the children follow the calling of their parents. The common
+misconception that deformities or postures associated with a trade, such
+as a shoemaker's or tailor's, is genetically stamped on offspring by the
+end of the third or fourth generation results from failure to discriminate
+between real inheritance and mere reappearances under similar conditions
+of environment.
+
+=Prenatal Infection Not Inheritance.--=Again, we must recognize that
+prenatal infection is not inheritance. We have already seen that the young
+mammal undergoes a certain period of intra-maternal development, but
+influences operating on it during this period of gestation must be
+reckoned with as environmental, not germinal. For example, it is said that
+an unborn child may take smallpox from its mother but this and all similar
+occurrences are cases of contagion. We find the great pathologist,
+Virchow, who with many others of his time was a believer in the
+inheritance of acquired characters, saying nevertheless regarding such
+instances that, "What operates on the germ after the fusion of the
+sex-nuclei, modifying the embryo, or even inducing an actual deviation in
+the development, can not be spoken of as inherited. It belongs to the
+category of early acquired deviations which are therefore frequently
+congenital."
+
+=Inheritance of a Predisposition Not Inheritance of a Disease.--=We must
+discriminate sharply also between the inheritance of a predisposition and
+the inheritance of a disease itself.
+
+We often hear the statement made that tuberculosis is inherited and have
+cited in evidence certain consumptive families or strains. But
+tuberculosis is a bacterial disease and children of tuberculous parents
+are never born with the disease except in the rarest of instances.
+
+=Tuberculosis.--=What is really inherited is a constitutional
+susceptibility to this particular germ. While almost any individual may
+contract tuberculosis when in a state of depressed vitality, or under
+stress of adverse surroundings, there is no doubt that certain families
+are more easily infected than others and much less resistant to the
+ravages of the disease when once it gains a foothold. However, a
+predisposition is a vastly different thing from the inheritance of the
+actual disease. For just as we are born with a nose well adapted to
+eye-glasses but not with eye-glasses on our nose, so many of us are born
+tuberculizable though not tuberculous, and every sanitary advance we make
+toward lessening the chances of infection is just so much more insurance
+for the susceptible.
+
+The whole problem of tuberculosis is an extremely complex one. We do not
+know just the measure of the inheritance of the predisposition. Some
+writers in the past have maintained that tuberculosis is mainly a question
+of infection and not of inherent susceptibility, but steadily increasing
+evidence all points the other way.
+
+Where the predisposition exists the chances of infection are still, even
+under the conditions of present-day sanitation, very great. The close
+association between a consumptive and other members of the family through
+a prolonged period of time, of course, renders the latter likely to
+infection unless unusual care is exercised. Very often where a parent is
+consumptive a child contracts the malady shortly after birth and is
+particularly likely to do so if the mother, who nurses it and cares for it
+most intimately, is the tubercular member of the family. Where the mother
+is tubercular, indeed, the probabilities are that the child has already
+before birth had its vitality lowered through the toxins circulating in
+her blood or through defective nutrition, and in consequence does not
+resist well any diseases.
+
+Undoubtedly a large proportion of our infant mortality is of tubercular
+origin. It is now a well-established fact that much tuberculosis in
+children is attributable to drinking milk from tuberculous cows, yet we
+find individuals so uninformed and dairymen so mercenary that they fight
+all attempts of the commonwealth to test out cattle for tuberculosis so as
+to condemn the infected individuals and thus save our babies. Recent
+investigations made in some of our large pork-packing establishments also
+indicate that hogs, especially such as have been around tubercular
+cattle, are often shot through and through with tuberculosis and that such
+flesh when used as food, if not thoroughly cooked, may become a serious
+menace to our health.
+
+With the wide prevalence of bovine and human tuberculosis it is little
+wonder that nearly every human being becomes more or less infected at some
+period of life. Autopsies on large numbers of individuals in some of our
+great hospitals have shown that as many as ninety-nine per cent. of the
+subjects show tubercular lesions of some kind. While it is true that the
+class of people who would come to autopsy in such public hospitals would
+perhaps be more likely to be tubercular than the average of the community,
+still it can not be denied that a very large degree of infection exists.
+Pearson, from statistics gathered in Europe, has shown that about eighty
+to ninety per cent. of the population have tubercular lesions before the
+age of eighteen. Hamburger found that in Vienna ninety-five per cent. of
+the children of the poor, between twelve and thirteen years of age, were
+infected with tubercular bacilli and he estimates that all would be before
+maturity. According to Doctor Mott, pathologist to the London County
+Asylums, the insane between the ages of fifteen and thirty-five are about
+fifteen times as likely to acquire tuberculosis as the sane are.
+
+Yet the mortality from tuberculosis, great though it be, is obviously not
+in proportion to the enormous degree of infection. The crux of the
+situation is mainly the matter of resistance. From the standpoint of
+heredity, therefore, the question largely resolves itself into one of the
+inheritance or non-inheritance of constitutional resistance. Some are
+predisposed to be non-resistant and hence succumb.
+
+The work of Karl Pearson[5] and other recent researches forcibly indicate
+that hereditary constitutional predisposition is one of the chief factors
+concerned in subjects who develop well defined attacks of the disease. Yet
+we must not forget that there are degrees of susceptibility and that
+therefore a constitutional predisposition which might be of little
+significance under good average conditions of nutrition and sanitation
+might be insufficient under unfavorable conditions.
+
+Before we can make any relatively accurate estimate of the exact degree to
+which the malady is based on inheritance we must have more data. Many
+difficulties beset the path of the investigator. In the first place, when
+one gets back a generation or two he finds that diagnosis was crude and
+uncertain; a given malady may or may not have been tuberculosis. The main
+error however was probably on the side of not recognizing it in mild or
+obscure cases. Then again the questions of virulence of the infection, of
+size and frequency of the dose, etc., are also complicating factors.
+Moreover, in very many cases the infection is a mixed one and hence we are
+dealing with other factors than straight tuberculosis.
+
+=Two Individuals of Tubercular Stocks Should Not Marry.--=However,
+sufficient is now known of the inheritance of susceptibility to the
+disease that we can have little conscience toward the welfare of the race
+if we in any way countenance the marriage of two individuals who come each
+of tubercular strains, and marriage of even a normal person into a badly
+tainted strain, where the one married is tubercular, is extremely
+hazardous looked at from the standpoint of the children likely to be born
+of such a union. The Supreme Court of New York recently held that the
+fraudulent concealment of tuberculosis by a person entering into a
+marriage relation is ground for the annulment of the marriage.
+
+=Special Susceptibility Less of a Factor in Many Diseases.--=With some
+diseases such as leprosy, typhoid fever, smallpox and cholera there seems
+to be less a question of special susceptibility since nearly all persons
+are vulnerable. Yet in cases of typhoid, at least, there are some
+indications that certain families are more likely to take the disease than
+others under similar exposure. We know of no inherited effects of such
+diseases, however. For instance, children of lepers do not inherit leprosy
+and if kept out of leper districts remain normal.
+
+=Deaf-Mutism.--=In certain abnormal states there is danger of confusing
+similar conditions which may have two entirely different sources of
+origin. Deafness, for example, may be strictly inborn as the outcome of a
+germinal variation or it may result from extraneous influences such as
+accidents, infective diseases, neglected tonsils and the like. The former
+is inheritable, the latter not. Bell in 1906 in a special census report to
+the United States government showed that deaf-mutism is markedly
+hereditary, particularly where deaf-mutes intermarry as they are prone to
+do. Fay's extensive studies on _Marriage of the Deaf in America_ also
+demonstrate the hereditary nature of the congenital forms of deafness. Cut
+off as such individuals are from communication with normal people, the
+association of the two sexes in special schools and institutions is of
+course highly conducive to such marriages. The defect seems to behave in
+the manner of a Mendelian recessive. Two deaf-mutes should not have
+children and yet such marriages are occurring every day. Even if two
+persons marry from families which tend to become hard of hearing the
+evidence indicates that their children are likely also to develop this
+partial deafness as they grow older, although it seems safe for a person
+of such tendency to marry into a family without it.
+
+=Gout.--=In such disorders as gout there is little question but that a
+tendency to it runs in families. On the other hand it may also be acquired
+without special susceptibility. There is no evidence, however, that
+because a father has gout the effect of the gout is reflected on his
+germ-cells and the son has gout as a result. Indeed, often a son who
+becomes gouty was born long before the father became gouty. Son and father
+both have gout then, because each has innate germinal tendencies which
+when subjected to certain evocative stimuli become expressed as gout.
+
+=Nervous and Mental Diseases.--=Inasmuch as the question of nervous and
+mental diseases has become one of such overshadowing importance at the
+present day, a discussion of the subject at some length will be presented
+in a separate chapter. I shall merely point out here that the general
+verdict of experts in nervous and mental disorders is to the effect that
+externally induced mental disorders are of rare occurrence except as the
+result of general poisoning or enfeeblement of the system in some way, or
+by traumatic conditions such as a blow on the head, and that there is no
+evidence of the transmission of the effects of such conditions. In most
+cases of insanity, supposedly caused by fright or worry, a close study of
+the family stock will reveal nervous instability of some kind. The
+supposed cause has been merely the precipitating stimulus which has
+brought to expression a dormant weakness of germinal origin. The stress
+and strain of modern life is particularly likely to test out and reveal
+such neurally unstable individuals.
+
+=Other Disorders Which Have Hereditary Aspects.--=Space will not permit
+discussion of various other specific disorders which are known to have
+important hereditary aspects, although none shows any convincing evidence
+of having become hereditary in nature through first affecting the soma.
+Some of these, such as epilepsy and other nervous affections,
+tuberculosis, color-blindness, cataract and various malformations, have
+already been mentioned. Others that may be listed are cancer,
+arterio-sclerosis, obesity and certain forms of rheumatism, and of heart
+and kidney diseases. In practically all of these cases in which heredity
+enters as a factor the condition is one of inheriting a special
+susceptibility and not the disease itself. Which means simply that the
+disorder in question is much more easily called forth in such persons by
+appropriate bacterial or other stimulus, than in the case of the normal
+individual.
+
+=Induced Immunity Not Inherited.--=Lastly, it is well known that various
+animals, including man, after recovery from an attack of any one of
+certain diseases, become more or less immune from further attacks of the
+same disease. Moreover in some instances as in inoculation against typhoid
+or diphtheria, immunity may be artificially induced by means of
+anti-toxins. The question arises as to whether such immunity is
+transmitted to offspring. Experiments have been made (see _Bulletin No.
+30, U. S. Hygienic Laboratory_) to test this and it has been found that
+the condition is not inherited. Young guinea-pigs, for instance, born of
+mothers immunized during pregnancy are immune at birth but they lose their
+immunity in the course of a few weeks. The effect is clearly one of direct
+transference from the blood of the mother. The same temporary immunity can
+be produced in the young, in fact, by merely having them nurse from an
+immunized mother.
+
+=Non-Inheritance of Parental Modifications Has Social, Ethical and
+Educational Significance.--=Like many other biological conclusions these
+relative to the non-inheritance of parental modifications are of extreme
+importance to humanity. It is clear that they have not only physical but
+social, ethical and educational significance. For if the education which
+we give our children of to-day, or the desirable moral conduct which we
+inculcate does not affect the offspring of succeeding generations through
+inheritance, then the actual progress of the race is much slower than is
+commonly supposed, and the advance of modern over ancient times lies more
+in an improvement in extraneous conditions through invention and the
+accumulation and rendering accessible of knowledge, than in an actual
+innate individual superiority. And when we face the issue squarely we have
+to admit that there is no more indication of the inheritance of parentally
+acquired characters as regards customs, knowledge, habits and moral
+traditions than there is of physical features. In fact, if such
+acquirements were inherited then we should soon have a race which would
+naturally, spontaneously as it were, do what its ancestors did with
+effort. Yet we do not find the children in our schools reading, doing sums
+and developing proper social relations without ceaseless prompting and
+urging on the part of the teacher. Indeed I can testify that this
+necessity carries over even into a university. In short, the habits and
+standards of each generation have to be instilled into the succeeding
+generation.
+
+=No Cause for Discouragement.--=At first glance when we realize that
+notwithstanding our individual advancement, that in spite of all our
+painstaking efforts toward self-improvement, we can not add one jot or
+tittle to the native ability of our children, that, aside from possible
+advantageous germinal variations, they will have to start in at
+approximately the same level as we did, and like us will have to struggle,
+or be coaxed, pulled or spurred up to the higher reaches of attainments,
+we are apt to feel discouraged and to look on heredity as the hand of fate
+which irrevocably bars progress. But there is another side to the picture.
+This very fact of heredity which can not be altered at will is the
+conservative factor which maintains the excellence of our standard strains
+of plants and animals, and sustains man himself at his present level of
+accomplishment. While we are denied advancement through the efforts of the
+flesh, we are also largely protected from our misfortunes and follies, as
+witness the non-inheritance of mutilations, of various maladies of
+extrinsic origin, or of personally acquired bad habits.
+
+=Improved Environment Will Help Conserve the Superior Strains When They Do
+Appear.--=If we can not hand on to our descendants a personally enhanced
+blood heritage, we at least can do our share toward building up a social
+heritage of established truth, of efficient institutions and of
+stimulating ideals, through which their dormant capacities may be led to
+expand more surely and more effectively to their uttermost limits. Each
+advance in such social heritage will tend more and more to create an
+atmosphere which will make it sure that the occasional real progressive
+and permanent variations which occur from time to time will find adequate
+expression and preservation in future lines of descendants. It will reduce
+the numbers of our "mute, inglorious Miltons" by more certainly disclosing
+the individual of exceptional talents and insuring for him an opportunity
+of revealing them to the best advantage. Above all, since surrounding
+influences are especially powerful on young and developing organisms, we
+should realize that great care must be exercised in behalf of the young
+child to secure an environment which is saturated with wholesome
+influences. For it is a rule of development that if the environment is
+faulty the organism is impaired.
+
+
+
+
+CHAPTER VI
+
+PRENATAL INFLUENCES
+
+
+=All That a Child Possesses at Birth Not Necessarily Hereditary.--=We come
+now to the more specific discussion of what may happen to offspring of
+mammals, and particularly man, in the interval between fertilization and
+birth; that is, during the intra-maternal period. We have already seen
+that anything affecting the offspring during this period has to be
+reckoned as environmental, our formula reading, Mammal = germ +
+intra-maternal environment + external environment. It is evident, then,
+that all that a child possesses at birth is not necessarily hereditary,
+since the unborn child may be influenced by conditions prevailing in
+either parent.
+
+=The Myth of Maternal Impressions.--=In order to clear the way for more
+urgent matters let us first inquire into the question of the production of
+changes in the unborn child as a result of "maternal impressions." As the
+tale generally goes, structural changes are produced in the unborn child
+corresponding to some mental experience of the mother, usually a vivid
+impression of strong emotion, but when a given individual is pinned down
+to sources, it is usually a case of hearsay.
+
+Stock examples are: The mother sees a mouse with the result that a
+mouse-shaped birthmark occurs on the child; or she sees a crushed hand
+and in consequence bears a child later with some of the bones of the hand
+missing; the mother touches her body when frightened and thus marks the
+unborn child on the corresponding part of the body; or she produces beauty
+in the child by long contemplation of a picture of a beautiful child; and
+so on almost endlessly. The favorite is usually the production of a red
+birthmark or marks on the child's body by strong desire on the part of the
+mother for strawberries, tomatoes, etc.--the fruit must be red since the
+mark is red--or by fright from seeing a fire. As a matter of fact it is
+not uncommon for the capillary blood vessels of the skin of a new-born
+infant to remain dilated in spots instead of contracting as they normally
+should do. The result is more or less of a red or "flame" spot. It is easy
+to see, therefore, why such birthmarks are so frequently referred back by
+the credulous mother to her desire for or fear of some red object.
+
+An analysis of the case of a child shuddering at the sight of peaches is
+of interest in this connection. The child showed the greatest aversion to
+peaches, particularly to the fuzzy covering. The mother's explanation was
+that peaches were unusually plentiful the year the child was born and that
+she had worked hour after hour at peeling and canning peaches shortly
+before his birth until she had become thoroughly sick of them. This
+acquired aversion on her part she believed had been transferred to the
+child. A few questions revealed the fact, however, that the mother,
+herself, had never liked peaches and when asked if they were distasteful
+to any other member of her own family she exclaimed, "Oh, yes, my mother
+would shudder and shake if a peach were brought near her." And there we
+have it. The idiosyncrasy was an inherited one as many similar
+peculiarities are. The mental impression produced in the mother by her own
+experience with peaches had nothing to do with its occurrence in the
+child.
+
+Very frequently also one encounters the mother who is sure she has
+engendered musical ability in her child by constant practise and study of
+music during pregnancy. The child is musical; what better evidence does
+one want! It seems never to occur to such a mother that the child is
+musically inclined because she herself is, as is evinced by her own desire
+in the matter even if she is not a skillful performer.
+
+When we take into account the extreme credulity of many people, the
+unconscious tendency of mankind to give a dramatic interpretation to
+events where causes are not certainly known, the hosts of coincidences
+that occur in life, and the multitude of cases where something should
+happen but nothing does, we are compelled to believe that the whole matter
+of direct specific influence of the mother's mind on the developing fetus
+is a myth. After seeing the conditions which prevail in Mendelism, for
+example, it will take strong faith to believe that a mother with duplex
+brown eyes can "think" or "will" blue eyes on her baby, yet this would be
+a mild procedure compared to some we are asked to accept by believers in
+the transmission of maternal impressions. Most of all, however, when we
+recall the actual relation between the embryo and the mother--a narrow
+umbilical cord is the sole means of communication between the two--the
+physical impossibility of a connection between some particular mental
+happening of the mother and a corresponding specific modification in the
+fetus becomes evident. For there are no nerves in the umbilical cord, the
+only path of communication between mother and fetus being the indirect one
+by way of the blood stream. Even this method of communication is limited
+inasmuch as the mother's blood does not circulate through the blood
+vessels of the fetus. Gaseous and dissolved substances are merely
+interchanged through the thin walls of the capillary blood vessels in the
+placenta.
+
+=Injurious Prenatal Influences.--=However, the denial that a particular
+mental impression of the mother is associated with a particular structural
+defect in a child does not carry with it the implication that prenatal
+influences of all kinds are negligible factors. On the contrary any
+deleterious effect which can reach the fetus through absorption from the
+blood of the mother may be of grave consequence. There is not the least
+doubt that malnutrition or serious ill-health on the part of the mother
+often has a prejudicial effect on the unborn offspring. Severe shock or
+grief, worry, nervous exhaustion, the influence of certain diseases,
+poisons in the blood or tissues of the parent, such as lead, mercury,
+phosphorus, alcohol and the like, may all act detrimentally, but they
+operate either by rendering nutrition defective, by direct poisoning, or
+by generating toxins in the blood of the parent which then poison the
+fetus. Among the latter may be mentioned the toxic products of
+tuberculosis and certain other bacterial diseases. Such factors operating
+on the unborn young or even on the germ-cells may cause malformations,
+arrests of development, instabilities of the nervous system, and general
+physical or mental weakness. The effects are general, however, and not
+specific.
+
+To distinguish certain of these prenatal effects, particularly those of
+certain diseases or poisons, from true hereditary influences they are
+frequently spoken of as cases of _transmission_ rather than inheritance
+from parents. Some writers use the technical term _blastophthoria_, or
+false-heredity, extending the meaning so as to include also any damage
+that might be inflicted on the germ-cells.
+
+=Lead Poisoning.--=By way of illustration of how certain cumulative
+poisons may act we may examine a tabulation of eighty-one cases of lead
+poisoning as reported by Constantin Paul (Fig. 29, p. 164).
+
+The table requires little comment. The disastrous effects of such
+poisoning are apparent in every class of cases. The sixth class where the
+husband alone was exposed to lead shows that the poison can operate
+directly through the germ-cell. Other observers note that in the children
+of workers in lead, there is a distressing frequency of feeble-mindedness
+and epilepsy.
+
+That lead poisoning operating through the germ-cells of the father can
+affect the development of the young harmfully is well shown in Fig. 30, p.
+165, which is a photograph of two young rabbits from the same litter The
+white young one is from a normal albino mother mated to an albino father
+which had received lead treatment. The pigmented young one is from the
+same albino mother by a normal pigmented father. Although the white
+father was considerably larger than the pigmented father, nevertheless the
+young of the former, because of the harmful effects of the lead, is
+distinctly smaller and less lively. A number of litters, each from the
+same mother but in part from a lead-poisoned father and in part from a
+normal father, have been secured. All show more or less the same results.
+The experiments are still in progress in the department of experimental
+breeding at the University of Wisconsin.
+
+  --------------------------------------------------------------------
+                       |Number of cases.
+                       |     +----------------------------------------
+                       |     |Number of pregnancies.
+                       |     |      +---------------------------------
+                       |     |      |Abortions, premature labor, and
+                       |     |      |  stillbirths.
+                       |     |      |     +---------------------------
+                       |     |      |     |Infants born living.
+                       |     |      |     |      +--------------------
+                       |     |      |     |      |Remarks.
+  ---------------------|-----|------|-----|------|--------------------
+  1. Mother showing    |     |      |     |      |One infant died
+  symptoms of plubism  |  4  |  15  |  13 |   2  | within 24 hours.
+                       |     |      |     |      |
+  2. Mother working in |     |      |     |      |
+  type foundry, all    |     |      |     |      |
+  of whose previous    |     |      |     |      |
+  pregnancies had      |     |      |     |      |Four of these died
+  been normal          |  5  |  36  |  29 |   7  | in first year.
+                       |     |      |     |      |
+  3. Mother who during |     |      |     |      |
+  period of work in    |     |      |     |      |After ceasing to
+  type foundry had     |     |      |     |      | work had
+  five pregnancies     |  1  |   5  |   5 |   0  | healthy child.
+                       |     |      |     |      |
+  4. Mother working    |     |      |     |      |When away from
+  intermittently in    |     |      |     |      | work for some
+  type foundry;        |     |      |     |      | period of time
+  while working        |     |      |     |      | gave birth to
+  there                |  3  |   3  |   3 |   0  | healthy children.
+                       |     |      |     |      |
+  5. Mother in whom    |     |      |     |      |
+  blue line on gum     |     |      |     |      |
+  the only sign of     |     |      |     |      |
+  lead poisoning       |  6  |  29  |  21 |   8  |
+                       |     |      |     |      |Of these, eight died
+  6. Husband alone     |     |      |     |      | in first year,
+  exposed to lead      |  ?  |  32  |  12 |  20  | four in second,
+                       |     |      |     |      | five in third.
+  --------------------------------------------------------------------
+
+FIG. 29
+
+Tabulation of eighty-one cases of lead poisoning recorded by Constantin
+Paul (from Adami).
+
+
+[Illustration: Fig. 30
+
+Photograph of young rabbits from the same litter, the smaller one stunted
+by lead-poisoning of its father (Courtesy of Professor L. J. Cole).]
+
+
+=The Expectant Mother Should Have Rest.--=The mere matter of rest on the
+part of the pregnant mother is, judging from the work of Pinard, a
+Frenchman, and his pupils, an important one. In a number of detailed
+investigations they have shown that rest on the part of the working mother
+during the last three months before the child is born results in the
+production of markedly larger and more robust children than those born of
+mothers equally healthy but who have not had such rest. Moreover the
+danger of premature birth is considerably lessened.
+
+=Too Short Intervals Between Children.--=Too short an interval between
+childbirths would also seem to be an infringement on the rights of the
+child as well as of the mother. Thus Doctor R. J. Ewart ("The Influence of
+Parental Age on Offspring," _Eugenic Review_, October, 1911) finds that
+children born at intervals of less than two years after the birth of the
+previous child still show at the age of six a notable deficiency in
+height, weight and intelligence, when compared with the children born
+after a longer interval, or even with first-born children.
+
+=Our Duty to Safeguard Motherhood.--=Doubtless the unventilated factory
+and tenement also do their share, even though we can give no exact
+quantitative measure of it. Obviously, it becomes a civic duty to protect
+as much as possible all members of our social system from such injurious
+factors as have just been discussed. It is particularly necessary to
+safeguard mothers before confinement, especially working mothers.
+
+=Expectant Mothers Neglected.--=According to the claims of life insurance
+men, expectant mothers are the most neglected members of our population.
+Doctor Van Ingen, of New York City, estimates that ninety per cent. of
+women in this country are wholly without prenatal care. Yet every
+prospective mother should be taught the probable meaning of such symptoms
+as headache, hemorrhages, swelling of the feet and disturbed vision. She
+should realize the importance of submitting a sample of urine for analysis
+at least once a month before childbirth and twice a month for a while
+thereafter. She should be specially informed regarding work, exercise,
+diet and dress. A recent government bulletin written by Mrs. Max West
+which may be had free by writing to the Children's Bureau, Department of
+Labor, Washington, D. C., gives much useful information on this subject.
+
+
+ALCOHOLISM
+
+=Unreliability of Much of the Data.--=One of the most important poisons
+that plays a prominent part among ante-natal influences is alcohol. But
+when it comes to a study of the problem of alcoholism from the standpoint
+of heredity and parental influences we meet with many difficulties,
+prominent among which are the inaccuracy and unreliability of many of the
+statistics brought forward in this connection. Many of the results are
+vitiated by the prejudices of propagandists who propose to make a case
+either for or against alcohol as a beverage whether or not the facts
+justify their conclusions. When one tries to view the matter with an open
+mind he finds that there is a deplorable lack of statistics which are not
+susceptible to more than one interpretation. However, using as much as
+possible what seems to be unbiased data, the evidence is almost wholly
+against alcohol as a beverage, at least to any immoderate extent.
+
+=Alcohol a Germinal or Fetal Poison.--=The bad effects as far as offspring
+are concerned reveal themselves in the main under the category of "false
+heredity," i. e., germinal or fetal poisonings rather than of heritable
+changes induced in the germ-cells. Most investigators feel that there are
+too many criminal, imbecile, insane and unhealthy persons among the
+offspring of drunkards to dismiss the matter as a coincidence. In an
+investigation of Imbault, for example, we find recorded of one hundred
+tuberculous children that while forty-one were of tuberculous parentage,
+thirty-six per cent, were the offspring of inebriates. Furthermore Imbault
+cites the observations of Arrive on 1,506 cases of juvenile meningitis to
+the effect that this malady is twice as frequent in the children of
+alcoholic as in those of tuberculous parentage. It has been proved by
+Nicloux (_L'Obstetrique_, Vol. 99, 1900) that in dogs and guinea-pigs
+alcohol passes through the placenta and may be detected in fetal tissues;
+hence it is in position to influence the fetus. He found that in a very
+short time the amount of alcohol in the blood of the fetus about
+paralleled that in the blood of the mother.
+
+=Progressive Increase in Death-Rate of Offspring of Inebriate Women.--=In
+an investigation on the effects of parental alcoholism on the offspring,
+Sullivan (_Journal of Mental Science_, Vol. 45, 1899) gives some
+important figures. To avoid other complications he chose female drunkards
+in whom no other degenerative features were evident. He found that among
+these the percentage of abortions, still-births and deaths of infants
+before their third year was 55.8 per cent. as against 23.9 per cent. in
+sober mothers. In answer to the objection that this high percentage may be
+due merely to neglect, and not to impairment of the fetus by alcoholism,
+he points out the fact based on the history of the successive births, that
+there was a progressive increase in the death-rate of offspring in
+proportion to the length of time the mother had been an inebriate, thus:
+
+  -------------------------------------------------------------
+                   |No. of|Per cent.|Per cent. dying|  Total
+                   |cases |born dead|   before 3    |percentage
+  -----------------|------|---------|---------------|----------
+  First births     |  80  |   6.2   |     27.5      |   33.7
+  Second births    |  80  |  11.2   |     40.8      |   50.0
+  Third births     |  80  |   7.6   |     45.0      |   52.6
+  Fourth and fifth | 111  |  10.8   |     54.9      |   65.7
+  Sixth to tenth   |  93  |  17.2   |     54.8      |   72.0
+  -------------------------------------------------------------
+
+=Views of a Psychiatrist on Alcohol.--=Forel, who for years was the
+psychiatrist at the head of a large insane asylum at Zurich, Switzerland,
+has this to say about the effects of narcotic poisons and alcohol in
+particular:
+
+    "The offspring tainted with alcoholic blastophthoria suffer various
+    bodily and physical anomalies, among which are dwarfism, rickets, a
+    predisposition to tuberculosis and epilepsy, moral idiocy, and idiocy
+    in general, a predisposition to crime and mental diseases, sexual
+    perversions, loss of suckling in women, and many other misfortunes."
+
+In another passage he[6] remarks as follows:
+
+    "But what is of much greater importance is the fact that acute and
+    chronic alcoholic intoxication deteriorates the germinal protoplasm of
+    the procreators.... The recent researches of Bezzola seem to prove
+    that the old belief in the bad quality of children conceived during
+    drunkenness is not without foundation. Relying on the Swiss census of
+    1900, in which there figure nine thousand idiots, and after careful
+    examination of the bulletins concerning them, this author has proved
+    that there are two acute annual maximum periods for the conception of
+    idiots (calculated from nine months before birth); the periods of
+    carnival and vintage, when the people drink most. In the wine-growing
+    districts the maximum conception of idiots is enormous, while it is
+    almost nil at other periods. Moreover, these two maximum periods come
+    at the time of year when conception is at a minimum among the rest of
+    the population, the maximum of normal conceptions occurring at the
+    beginning of summer."
+
+Another interpretation of Bezzola's results has been suggested to the
+effect that the license of these periods enables the defective members of
+the community, such as the feeble-minded, an opportunity of mating more
+readily and that consequently the result is direct inheritance of idiocy
+and allied defects instead of idiocy produced through alcoholic poisoning
+of the parental germ-cell.
+
+=Other Views.--=There are indeed many competent investigators who believe
+that alcoholism in parents has little or no part in the direct production
+of mental defects in children. For instance, Tredgold quotes Doctor
+Ireland's observations that although at New Year, when the fishermen
+return, the whole population of certain villages in Scotland gets drunk,
+there is no noticeable excess of defectives born nine months later, and
+remarks further that, "I have histories of idiots conceived under such
+circumstances, but so I have of normal children, and my opinion is, that
+while this may be a cause in some cases, the number of instances in this
+country at any rate is exceedingly small." Again, Goddard, one of our best
+known American students of feeble-mindedness, who has made careful study
+of this point under especially favorable conditions, feels that his data
+do not prove that alcoholism of either the father or the mother causes
+feeble-mindedness in the child. He concludes, "Everything seems to
+indicate that alcoholism itself is only a symptom; that it for the most
+part occurs in families where there is some form of neurotic taint,
+especially feeble-mindedness." Goddard, however, in common with many other
+observers, notes that miscarriages and deaths in infancy are far higher
+among inebriates than among abstainers.
+
+Doctor Mjoeen cites an interesting parallel between the increase of
+feeble-mindedness in Norway and a period from 1816 to 1835, when every one
+was permitted to distil brandy. In some districts many of the farmers
+distilled brandy from corn and potatoes, and in such regions during this
+period feeble-mindedness increased nearly one hundred per cent. Later the
+home distillation of brandy was stopped. According to Doctor Mjoeen, "The
+enormous increase in idiots came and went with the brandy." He is
+inclined to believe, however, that the alcohol operated injuriously mainly
+on stocks already defective.
+
+=The Affinity of Alcohol for Germinal Tissue.--=Nicloux and Renault have
+shown that alcohol has a decided affinity for the reproductive glands. In
+individuals who have recently taken alcohol the proportion of alcohol in
+the gonads is soon almost equal to the amount found in the blood. Thus in
+experiments on mammals it was found that the proportion of alcohol in the
+ovary to that in the blood was as three to five, and in the testis as two
+to three. This would afford abundant opportunity for alcohol to act
+directly on the spermatozoon or the ovum.
+
+A number of different investigators concur in finding that the germ-glands
+of the male human inebriate in many cases show more or less atrophy and
+other degenerative changes. In guinea-pigs which have been repeatedly
+intoxicated with alcohol, Stockard found that while he could detect no
+visible abnormality in the gonad, nevertheless their defective and
+weakened progeny showed that the germ-cells had been affected.
+
+=Innate Degeneracy Versus the Effects of Alcohol.--=Many observations on
+human beings have been brought forward which at first sight seem to
+indicate that noticeable defects, particularly mental and nervous, occur
+with appalling frequency in children resulting from conception during
+intoxication, although, unfortunately, the evidence is rarely clear as to
+whether the defects are really due to the effects of the alcohol or to the
+fact that the parent or parents were degenerate to begin with.
+
+A very interesting human case cited by Forel on the authority of
+Schweighofer is that of a normal woman who had three sound children when
+married to a normal man. After the death of this husband she married an
+inebriate by whom she had three other children. One of these suffered from
+infantilism, one turned out to be a drunkard, and the third became a
+social degenerate and drunkard. Moreover the first two contracted
+tuberculosis, although hitherto the family stock had been free from this
+malady. Ultimately the woman married again and by this third husband, who
+was normal, she again had sound children. Similar cases might be cited,
+as, for example, a record of eighty-three epileptics, of whom sixty had
+drunken parents, but it can be urged against all of them, of course, that
+the defective offspring were due to an innate degeneracy of the drunken
+parent which made him a drunkard rather than to the effects of the alcohol
+he took. While one is skeptical as to the validity of this objection in
+all of the many cases which occur with such monotonous frequency in man,
+there is no way of escaping such an interpretation with the evidence at
+hand. It must be admitted, moreover, that there are many families with one
+or both parents alcoholic in which the children are not mentally
+defective.
+
+=Experimental Alcoholism in Lower Animals.--=Many of the objections that
+exist in the case of man, however, do not apply in that of lower animals.
+If normal animals are experimentally alcoholized and are shown to produce
+defective offspring under such conditions, then in their cases at least,
+the disorders in the offspring must be due to the effects of alcohol and
+not to an innately degenerate condition of the parent. Disorders similar
+to some of those seen in the children of alcoholics do actually result in
+alcoholized animals of one kind or another.
+
+Against the earlier experiments on animals it has been urged that too few
+individuals were used to give conclusive results, but this objection can
+not be brought against the recent experiments of Stockard. While he has
+published accounts of his work in various scientific periodicals lately,
+the reader will find a full statement of his own experiments, together
+with a review of the whole subject of experimental alcoholism in animals
+and the effects on progeny in _The American Naturalist_, Vol. XLVII,
+November, 1913, together with a useful bibliography.
+
+Before taking up Stockard's results we may select a few of the more
+significant experiments made earlier by other investigators.
+
+Laitinen alcoholized rabbits and guinea-pigs. He found that the treated
+individuals had more still-born young than the control, and also that
+growth of the living young was retarded. His alcoholized rabbits and
+guinea-pigs produced more young than did the normal individuals used as a
+control. Laitinen's studies on man, together with three other studies of
+the Eugenics Laboratory in London, show that in man also more children are
+born to alcoholics than to normal parents. Goddard's investigations in
+America corroborate this fact.
+
+Ceni found that only 43 per cent. of the eggs from alcoholized fowls
+developed normally, as against 77 per cent. of normal development in the
+controls. Moreover the eggs of alcoholic fowls were shown to be less
+resistant to adverse conditions than normal eggs from the fact that
+fluctuations of temperature at the beginning of incubation kept all the
+alcoholic eggs from developing perfectly, while 27 per cent. of the
+control eggs developed normally under the same adverse circumstances.
+
+Hodge made a pair of dogs alcoholic. Of 23 pups obtained from the pair, 8
+were deformed and 9 were dead; 4 alone were viable. From a control pair of
+dogs 45 pups were obtained, of which 4 were deformed, none were born dead,
+and 41 were viable.
+
+=Stockard's Experiments on Guinea-Pigs.--=Stockard's experiments
+demonstrate that the offspring of mammals may be injured or modified in
+their development by treating either parent repeatedly with alcohol. The
+guinea-pigs used in the experiment were all first tested by normal matings
+and found to yield normal offspring. The alcohol was given to them by
+inhalation. It was found to be readily taken into the animals' blood and
+to produce intoxication. While guinea-pigs alcoholized in this way as
+often as six times a week for two and one-half years would maintain their
+own bodily vigor and health apparently, the deleterious effects on their
+progeny were marked. The defects were general rather than specific,
+although the central nervous system and special sense organs were
+apparently affected most.
+
+Out of 119 total young produced by the alcoholic animals, only 52, or less
+than 44 per cent., survived, whereas out of 64 young produced from normal
+parents used as a control for the experiment, 56, or over 87 per cent.,
+survived. In some cases alcoholic males were mated with normal females, in
+other, alcoholic females with normal males. In still other instances both
+parents were alcoholic.
+
+The results are summarized in the accompanying table (Fig. 31), taken from
+Stockard's paper:
+
+  CONDITION OF THE OFFSPRING FROM GUINEA-PIGS TREATED WITH ALCOHOL
+
+  -----------------------------------------------------------------
+                      |Number of Matings
+                      |     +--------------------------------------
+                      |     |Negative Result or Early Abortion
+                      |     |    +---------------------------------
+                      |     |    |Stillborn Litters
+                      |     |    |    +----------------------------
+                      |     |    |    |Number Stillborn Young
+                      |     |    |    |      +---------------------
+                      |     |    |    |      |Living Litters
+                      |     |    |    |      |    +----------------
+                      |     |    |    |      |    |Young Dying Soon
+                      |     |    |    |      |    |  After Birth
+                      |     |    |    |      |    |      +---------
+  Condition of        |     |    |    |      |    |      |Surviving
+   the Animals        |     |    |    |      |    |      |  Young
+  --------------------|-----|----|----|------|----|------|---------
+  Alcoholic [male] by |     |    |    |      |    |      |
+    normal [female]   |  59 | 25 |  8 |  15  | 26 |  21  |  33
+  Normal [male] by    |     |    |    |      |    |      |
+    alcoholic [female]|  15 |  3 |  3 |   9  |  9 |   9  |  10
+  Alcoholic [male] by |     |    |    |      |    |      |
+    alcoholic [female]|  29 | 15 |  3 |   6  | 11 |   7  |   9
+  SUMMARY             | 103 | 43 | 14 |  30  | 46 |  37  |  52
+  Normal [male] by    |     |    |    |      |    |      |
+    normal [female]   |  35 |  2 |  1 |   4  | 32 |   4  |  56
+  2d generation       |     |    |    |      |    |      |
+    by normal         |   3 |  0 |  0 |   0  |  3 |   0  |   4
+  2d generation       |     |    |    |      |    |      |
+    by alcoholic      |   3 |  0 |  2 |   5  |  1 |   0  |   2
+                      |     |    |    |1 def.|    |      |
+  2d generation       |     |    |    |      |    |      |
+    by 2d generation  |  19 |  7 |  0 |   0  | 12 |   6  |  13
+                      |     |    |    |      |    |1 def.|
+  Female treated      |     |    |    |      |    |      |
+    during pregnancy  |   4 |  0 |  0 |   0  |  4 |   1  |   7
+  -----------------------------------------------------------------
+
+FIG. 31
+
+Table showing condition of the offspring from guinea-pigs treated with
+alcohol (after Stockard).
+
+Lines four and five give a comparison between the 103 total matings of all
+treated individuals and 35 normal matings. In the first case almost 42 per
+cent. of the matings gave negative results or early abortions, whereas in
+the normal control matings, failure to yield a full-term litter occurred
+in only two cases. The 103 matings of alcoholic animals gave only 46
+living litters, or about 45 per cent. On the other hand the 35 control
+matings produced 32 living litters, or 91-1/2 per cent. It will be
+observed also that from such of the 103 matings of alcoholics as produced
+young there were 30 still-born, 37 which died soon after birth, and only
+52 surviving young, whereas from the 35 matings of normal individuals
+there were only 4 still-born young, 4 which died soon after birth, and 56
+surviving young.
+
+The bottom line of the table, although, as Stockard points out, containing
+too few cases to prove wholly convincing, indicates that alcoholizing
+erstwhile normal females during pregnancy was not particularly harmful to
+the embryos _in utero_.
+
+Some of the most interesting results were obtained when offspring termed
+second generation animals, derived from alcoholic parents though not
+themselves treated with alcohol, were mated in various ways. When such
+individuals were mated with normal individuals, although the litters were
+small, the results were normal, the normal mate having seemingly
+counteracted any defects which might have lurked in the second generation
+animal. On the other hand, out of three matings of second generation
+animals with alcoholic individuals, two produced still-born young, of
+which one was markedly deformed, while the third yielded two living young.
+
+However, the most striking results were obtained when two second
+generation individuals, the offspring of alcoholic parents, were bred
+together. Although themselves untreated, these individuals, of which 19
+matings were made, produced as many or more defective young than did their
+alcoholic parents. Seven of the matings were unfruitful. The remaining 12
+matings gave living litters consisting of 19 individuals in all. Six of
+these showed various nerve disorders (spasms, epileptic-like seizures,
+etc.) soon after birth; one was eyeless and otherwise deformed.
+
+=Stockard's Interpretation.--=Stockard's interpretation of his experiments
+is as follows: "Mammals treated with injurious substances, such as
+alcohol, ether, lead, etc., suffer from the treatments by having the
+tissues of their bodies injured. When the reproductive glands and
+germ-cells become injured in this way they give rise to offspring showing
+weak and degenerative conditions of a general nature, and every cell of
+these offspring having been derived from the injured egg or sperm-cell are
+necessarily similarly injured and can only give rise to other injured
+cells and thus the next generation of offspring are equally weak and
+injured and so on. The only hope for such a line of individuals is that it
+can be crossed by normal stock, in which case the vigor of the normal
+germ-cell in the combination may counteract, or at any rate reduce, the
+extent of injury in the body cells of the resulting animal."
+
+He also believes that various deformities and developmental arrests such
+as harelip and cleft-palate may similarly be cases of transmission rather
+than true inheritance, due to the weakening of the germ-cells in some way,
+or to some lack of full vigor in the uterine environment.
+
+=Further Remarks on the Situation in Man.--=Returning now to the question
+of alcoholism in man, it seems in view of the strong circumstantial
+evidence in the case of man himself, together with the result of
+experiments on animals, that little doubt remains that excessive
+alcoholism might result in the production of defective offspring. On the
+other hand an antecedent degeneracy or neural instability undoubtedly
+plays an important part in many cases, in the original production of
+drunkards, and when such occurs, it, as well as the direct effects of
+alcoholic poisoning, must be reckoned with in the effects on progeny.
+Studies carried on by Pearson, Elderton and Barrington of the Eugenic
+Laboratory in London lead these investigators to the conclusion that
+extreme alcoholism is a _result_ not a _cause_ of degeneracy. That is, the
+degeneracy is due to the defective stock, not to alcohol. They cite in
+evidence their records of four thousand school children of alcoholic and
+of sober parents, which fail to show any unfavorable effect of alcohol on
+offspring. Some of their critics, however, maintain that they did not
+choose subjects who were sufficiently alcoholic to give the injurious
+results that might legitimately be expected among the offspring of
+excessive drinkers or habitual drunkards.
+
+Where children show a hereditary inclination toward drink, unquestionably
+one of the strongest factors is the inheritance of the same disposition,
+the same unstable nervous constitution and its accompanying lack of
+self-control which led the parent to drink, rather than the inheritance of
+the effects of the drink on the parent. For in many cases a parent may not
+become a drunkard until after the children who also become drunkards are
+born. That the tendency to drink immoderately is frequently due to a
+strain of feeble-mindedness or epilepsy becomes more evident every day.
+In many of the so-called "periodical" drunkards, the accompanying features
+of their periodic attacks of drink-craving, such as clouding of memory,
+restlessness and depression, are those commonly associated with ordinary
+epileptic attacks.
+
+=Probably Over Fifty Per Cent. of Inebriety in Man Due to Defective
+Nervous Constitution.--=Branthwaite, an English authority on drunkenness,
+finds that about sixty-three per cent. of the inebriates who come to his
+notice are mentally defective. In alcoholic insanities heredity is a
+potent factor. It is coming to be realized more and more that pronounced
+alcoholism is due in a large percentage of cases, perhaps over half, to a
+defective nervous make-up. While it is true that many drunkards would not
+develop without free access to alcohol, on the other hand many would never
+develop without a bad heredity back of them, which gives them a peculiar
+nervous constitution that renders alcohol an undue stimulus. In a recent
+report of the New York State Hospital Commission it is stated that in
+fifty-four per cent. of the cases of alcoholic insanity, a family history
+of insanity, epilepsy or nervous disease exists. Thus in the presence of
+alcohol most of these unfortunates are helpless pawns of a hereditary
+weakness.
+
+So when the question of alcoholism is viewed from all angles, the children
+of the human drunkard would seem to run a double menace of misfortune,
+since they may be subject both to the direct poisoning effects of alcohol
+and the results of an inheritable degeneracy.
+
+=Factors to Be Reckoned With in the Study of Alcoholism.--=In any
+thoroughgoing study of alcoholism in man many factors will have to be
+reckoned with. First of all there is the question of inherent lack of
+control. This is probably the principal thing inherited where heredity
+truly enters as a factor. That example and social environment are
+important factors in addition to or in place of heredity is clear, too,
+when we observe that often it is the boys only who take after a drunken
+father, for there is no evidence that the inherited tendency when it
+really exists is at all sex-linked. Again, in certain occupations carried
+on under unwholesome influences relief is frequently sought in alcoholic
+stimulants, and such custom may easily crystallize into habit.
+Furthermore, the accustoming young children to doses of alcohol, or the
+unborn young to alcohol through the body of a drunken mother, may be
+strongly contributory toward establishing inebriety in certain cases. As
+we have seen from an abundance of experimental data on animals, moreover,
+the nurture effects on germ-cells may result in the production of weakened
+offspring. Such offspring in the case of man are probably less able to
+withstand temptations of all kinds and hence readily succumb to the
+habit-forming effects of alcohol if once its use is begun. Lastly, it must
+not be forgotten that alcoholism in the father usually means poverty and
+the subsequent accompaniment of malnutrition and neglect of the children,
+and this in itself may not only account for poor development of the
+latter, but may also be strongly contributory toward establishing the
+habit of alcoholism in them.
+
+An inherent bias plus most of the other conditions just enumerated is the
+not unusual lot of the offspring of drunkards.
+
+=Venereal Diseases.--=There is yet another very considerable class of
+maritally unfit who in any conscientious discussion of unfitness for
+marriage or of racial improvement must be considered. I refer to those who
+are afflicted with the diseases which are inseparably associated with the
+so-called "social evil." To _gonorrhea_, one of the most prevalent of
+these diseases, more than one-fourth of our total one hundred and ten
+thousand blind in the United States are said to owe their affliction.
+Milder types of eye disease may also result from such infections. As much
+as eighty per cent., or some say practically all blindness in children
+born blind is caused by it, the infection occurring at the time of birth
+or within a few days thereafter. The terrible consequences of this disease
+to the innocent wife would alone make its discussion imperative.
+
+=The Seriousness of the Situation.--=Unfortunately the insidious nature of
+gonorrheal infections is unknown to most persons. A cure is apparently
+effected, yet as a matter of fact the germs may live for years and, if in
+the male, later be transmitted to the wife, subjecting her to a future of
+invalidism and misery. Reliable statistics from various medical
+authorities reveal the appalling fact that seventy-five per cent. or more
+of the surgical operations for inflammatory pelvic disorders peculiar to
+women, such as pus tubes and peritonitis, are attributable to this
+disease, as is also the involuntary sterility of forty-five per cent. of
+childless women. Unwelcome as the fact is there is an abundance of
+evidence to show that a large percentage of men in particular have at
+some period of their life been infected with venereal disease. Of our
+fourteen million males in the United States under the age of thirty we
+find estimates by some specialists in venereal diseases to the effect that
+five million of them, that is, one out of three, suffer from some one of
+the social diseases or their consequences. Doctor Hugh Cabot, one of the
+chief surgeons of the Massachusetts General Hospital at Boston, a member
+of the faculty of the Harvard Medical School and president of the American
+Association of Genito-Urinary Surgeons, has this to say about the
+situation: "We have of late years heard much about the frequency and
+serious consequences of tuberculosis; it has been dubbed the 'white
+plague,' and so active has been the campaign that a wide-spread
+understanding of this serious disease has resulted. It may safely be
+averred that in the urban population at least there are two, and perhaps
+three, individuals with syphilis to every one with tuberculosis. The
+frequency of gonococcus infection is much higher." He believes that over
+half the male population acquire a gonococcus infection at some period of
+their career. While as a layman, one can not but feel that a specialist's
+estimate may run unduly high because of the fact that he is encountering
+an inordinate proportion of such maladies every day, still such
+specialists are in position to get at the truth as no other person can and
+their calculations are probably not grossly in error. In any event any one
+who has progressed in worldly knowledge beyond the naivete of a child must
+recognize the appalling prevalence of these maladies.
+
+=Infantile Blindness.--=So serious has the matter of infantile blindness
+become that some state boards of health and some city health departments
+supply all physicians and midwives with specially prepared packages
+containing cotton and nitrate of silver solution for preventive or
+curative treatment of the eyes of all new-born children. At the time of
+the first bath each eye is carefully washed with a separate pledget of
+cotton saturated with boric acid solution. Each then receives a drop of
+the silver solution, which is made just strong enough to kill any
+gonococci that might be present without itself inflaming the eye. Water
+used in bathing the baby's body of course is not allowed to come in
+contact with its eyes. Such treatment should be given every child no
+matter how unsuspicious the circumstances may be. German authorities who
+have been following this method now for some years assure us that
+nineteen-twentieths of the blindness of infancy can thus be prevented.
+
+=Syphilis.--=As to _syphilis_, another and even more terrible of these
+diseases, we have before us the absurd fact that while thousands upon
+thousands of dollars are being spent to establish a rigid inspection and
+preventive measures against the spread of a very similar disease in the
+horse, this malady in man is allowed to pass unchallenged and we are
+confronted by the gruesome certainty that there are hundreds of these
+diseased persons about us to-day who, on their mere affirmation that they
+are unmarried and of age, will be given the right to marry and thus
+produce families of infected children irrevocably doomed to early death or
+to lifelong misery.
+
+While syphilis is most commonly spread through relations between the
+sexes, it may be acquired in various other ways, as for example, through a
+cut in shaving with the same razor an infected individual has used. It is
+commonly transmitted from parent to child. Practically every prostitute is
+a center of dissemination. Katherine Bement Davis has shown in her studies
+made at the New York State Reformatory for Women that while ordinary
+clinical tests show that apparently only twenty-one per cent. of these
+women are infected with venereal disease, more careful laboratory tests
+showed at least ninety per cent. to be infected.
+
+Syphilis is caused by _Treponema pallidum_, a small unicellular animal
+parasite. Given access to the blood by any means whatever, possibly even
+through an abrasion in the lip by means of a kiss, it multiplies rapidly
+and any part or organ of the body may be attacked. Usually a small sore
+occurs at the point of entrance to the body, but often it heals up readily
+with little indication of the seriousness of the infection.
+
+The development of the malady is insidious and long continued. As a matter
+of clinical convenience physicians divide its progress into successive
+stages although in reality the transitions are frequently variable and ill
+marked. The symptoms that arise within the first few months or even years
+are readily controlled by appropriate treatment, but to insure a cure
+prolonged and most thoroughgoing treatment is imperative. The symptoms
+disappear so completely after a short period of treatment that it is very
+difficult to persuade the average patient that he is not yet cured. Two
+years at least are none too short a period of treatment, yet the majority
+of patients, fully convinced that they are merely being exploited by the
+physician as a source of revenue, drift away at the end of a few months.
+As a matter of fact, however, the germs usually persist long after the
+obvious symptoms of the disease have disappeared, and in consequence many
+of the most serious results of syphilis may not manifest themselves for a
+period of perhaps ten, twenty or thirty years.
+
+=Some of the Effects.--=It is now known that _paresis_, also termed
+general paralysis or softening of the brain, is probably invariably due to
+syphilis. The work of Flexner and Noguchi on _paresis_ and _tabes
+dorsalis_ show that always in such afflictions the tissues of the central
+nervous system have been invaded by the parasite. The original infection,
+however, may have occurred so long before as to have been almost forgotten
+by the patient. Thus many an apparently robust man is stricken down in the
+prime of life. Earlier and prolonged treatment would in all probability
+have eradicated the germs and thus prevented the mental breakdown, which
+can not be cured by any known treatment. Postmortem examination always
+shows that the _Treponema_ has wrought wide-spread damage in the brain.
+The frequency of paresis may be realized when one learns that in some
+regions it is responsible for about one-fifth of all cases of insanity
+sent to hospitals for the insane. It ranks next to the highest as a cause
+of insanity. Statistics show that in the state of New York more deaths
+result annually from paresis than from smallpox, tetanus, malaria,
+dysentery and rabies all combined.
+
+In some cases the disease attacks the membranes of the brain and the small
+blood vessels giving rise to a still different type of mental disorder.
+Practically all patients with _locomotor ataxia_ owe their condition to an
+antecedent syphilis. Moreover it is one of the important causes of
+_arterio-sclerosis_, or hardening of the blood vessels, and is also a
+prominent factor in certain forms of heart-disease, as well as by no means
+an unimportant cause of blindness in children.
+
+As to specific cases of the effects of this disease on descendants the
+literature of the subject is crowded full. While it is needless to conduct
+the reader through a chamber of horrors by reviewing clinical cases, it is
+desirable to point out in a general way some of the effects. Doctor George
+H. Kirby, director of Clinical Psychiatry, Manhattan State Hospital, says:
+
+    "We find that when either the father or the mother suffers from
+    paresis that many other members of the family may be infected with
+    syphilis, and furthermore, we find that a large number of children in
+    these families are feeble-minded, nervous, or in other ways abnormal.
+    Doctor Plant examined a group of 100 children, the offspring of cases
+    of paresis, and found that 45 per cent. were plainly damaged mentally
+    or physically, or in both fields; the blood test showed that one-third
+    of these 100 children had the syphilitic poison in their systems.
+
+    "Another investigator found in a group of 139 children, the
+    descendants of parents who had syphilitic nervous disease, that over
+    25 per cent. were definitely feeble-minded or affected with some
+    serious nervous disorders.
+
+    "Other studies indicate that there exists a close relation between
+    syphilis and many of the hitherto unexplained cases of
+    feeble-mindedness, including idiocy, imbecility, infantile paralysis,
+    and some forms of epilepsy. While the question is not yet settled, it
+    appears that syphilis is the real cause of many of these cases of
+    mental defect in children."
+
+Still other investigators give details of physical afflictions and
+distortions, of suppressed development, of inordinate percentages of
+stillbirths--perhaps the most merciful lot for the little victims--but
+sufficient has been said to indicate the full horror of the situation.
+
+Goddard,[7] although not minimizing the terrible nature of the disease,
+finds little evidence in his studies that syphilis in parents is a
+specific cause of feeble-mindedness.
+
+=A Blood Test.--=Fortunately a delicate blood test known as the Wasserman
+test has been discovered by means of which, through an examination of a
+few drops of blood, any trace of syphilitic poison which exists in the
+body may usually be detected. This is true even though the individual may
+at the time show no visible symptoms of syphilis. The test is therefore of
+great value in detecting the latent germs of syphilis in individuals who
+have apparently been cured, and also often in making an early diagnosis of
+paresis. The Wasserman test, however, is reliable only in the hands of a
+skilled operator. It may occasionally give a positive reaction when
+syphilis does not exist and on the contrary a negative when it is present.
+The _luetin_ test is also now applied by some specialists, but is too new
+a test to have come into general use. It works on the same principle as
+the tuberculin test for tuberculosis. Some army physicians now also give
+what is termed a provocative Wasserman. That is, in a suspicious case
+which gives only negative results by an ordinary Wasserman, they can get,
+if syphilis really exists, a positive reaction after giving small doses of
+potassium iodide or salvarsan.
+
+It should be well understood by every one that syphilis is usually curable
+provided the patient is given modern scientific treatment by a _competent_
+physician. I emphasize competent because there are so many quacks in this
+field that one undergoing treatment can not be too careful in assuring
+himself of the competency of the physician. In even a case of long
+standing, where the symptoms have been in abeyance for a number of years,
+the disease can be cured provided it has not developed into an active
+cerebro-spinal type, and even the latter can be much benefited by proper
+treatment. The great danger of the cerebro-spinal type is that it will
+result in paresis or locomotor ataxia.
+
+As long as the blood of a patient shows a _positive_ Wasserman reaction,
+marriage should certainly not be consummated. If after a proper course of
+treatment by a well-informed physician, the patient shows a _negative_
+Wasserman when tested by a competent examiner, he probably would not
+infect his wife or offspring, although prudence would require that he wait
+at least six months or a year before marriage, and marrying then only if
+later tests remain negative.
+
+The only way for a patient to be sure that he is not harboring the
+cerebro-spinal form would be to have a spinal puncture made and the
+cerebro-spinal fluid examined. While the cerebro-spinal phase often does
+not occur until long after the primary infection, cases are known in which
+it has appeared within a few weeks. Evidence that the central nervous
+system is frequently invaded early in the course of the disease is
+increasing. Marriage of an individual suffering from the cerebro-spinal
+form should not take place, since such a one is almost sure to become a
+burden on the family or the state.
+
+=Many Syphilitics Are Married.--=It may seem to some that in a treatise on
+being well-born the subject of syphilis might be ignored as not being
+especially pertinent, but the supposition that no considerable percentage
+of syphilitics marry is not borne out by the facts. Seventy-five per cent.
+of men with insanity due to syphilis who are admitted to hospitals are
+married. The insanity in such cases is mainly the result of infections in
+earlier years, often long before marriage. While syphilis, strictly
+speaking, is not inherited, that is, does not become part and parcel of
+the germ-plasm, still the frequency of its direct transmission to
+offspring is so appalling that the outcome, as far as the immediate child
+is concerned, is quite as disastrous as the most thoroughgoing real
+inheritance could be.
+
+=Why Permit Conditions to Continue as They Are?--=When one faces the
+easily ascertained facts regarding venereal disease, it seems incredible
+that we, an intelligent people, can go on complacently handing our
+daughters and sisters over to the surgeon's knife and a life of personal
+misery, and even in not a few instances to become mothers of incurably
+defective children, yet the dire fact confronts us that we do. We can no
+longer excuse ourselves on the plea of ignorance, for the grisly record
+may now be read in many medical and not a few popular treatises, and we
+find the theme entering even into the modern drama, as witness Brieux's
+_Damaged Goods_. Further indifference to these conditions can only be
+attributed to culpable apathy or prudery.
+
+The extreme dangers to which parents are subjecting their daughters if
+they do not demand a clean bill of health on the part of their prospective
+husbands are obvious. Fathers and mothers perfectly willing to inquire
+into their future son-in-law's social connections, his income, securities,
+or business chances become strangely "modest" when it comes to determining
+whether he is physically fit for marriage.
+
+One great cause of ignorance in the past was the prudish taboo against
+frank discussions of venereal diseases which has thrown the veil of
+silence about the subject. To-day, however, it is coming to be recognized
+that these maladies are diseases and not a standard of social propriety,
+and that like most other diseases the surest way to secure prevention and
+gradual eradication is through the enlightenment of the public. They are
+prevalent in all classes of society. Moreover, it must not be forgotten
+that there is no form of venereal disease which may not be innocently
+acquired. Even where acquired through transgression of moral law an
+ignorant attitude toward the sexual instinct is often at the bottom of the
+difficulty.
+
+=Medical Inspection Before Marriage.--=Ante-nuptial medical inspection is
+certainly as necessary to the welfare of society as the certification of
+age and of the single state now required by law. No one objects to a
+medical examination pertaining to venereal and other diseases when it
+comes to taking out a life insurance policy, and why there should be any
+more objection to it as a preliminary to marriage is a mystery. A few
+states already have compulsory ante-nuptial medical inspection. The laws
+have been enacted too recently to judge adequately of their working. There
+has been much debate in Wisconsin as to whether their law (Chapter 738,
+Laws of 1913), which went into effect January 1, 1914, is constitutional
+and whether it requires a Wasserman test. The Wisconsin law applies to
+males only. The Supreme Court of the state has declared it constitutional
+and that its requirement of "the application of the recognized clinical
+and laboratory tests of scientific search" involves only such examination
+as the ordinary licensed physician is equipped to make and can reasonably
+be expected to make for three dollars, the maximum fee specified in the
+law.
+
+A number of the physicians of the state are still dissatisfied with the
+wording, although most do not oppose the principle of the law. Many
+believe that it should apply to the women as well as to the men, and
+others feel that the law should be extended to cover still other kinds of
+marital unfitness. Most of the practitioners with whom I have discussed
+the matter appreciate the motive underlying the law and are endeavoring to
+make it successful.
+
+The general public of the state as a whole seems to be in favor of the
+provision. At least one hears much favorable comment and little
+dissension among those who understand its purpose. The very controversy
+over it which sprang up after its passage proved to be of great benefit in
+the education of the public regarding the necessity of such measures. Such
+physicians as I have been able to question report that the candidates for
+marriage rarely object to the requirement, but on the contrary strongly
+favor it. Especially where they have suffered from venereal disease
+earlier in life most are eager to know their condition and to have medical
+advice. To my own mind this last fact is the most significant of all, as
+it will give every candidate for marriage a chance to know the truth. Most
+men are not so much brutal or vicious as ignorant in such matters. The
+vast majority of those unfit for marriage as a consequence of venereal
+disease will, when they realize the danger their condition imposes on wife
+and children, take every possible means to put themselves into proper
+condition.
+
+Desirable as the Wasserman test may be, it requires special laboratory
+facilities and equipment as well as a specially trained examiner to make
+it a reliable test. Moreover it can not be given by the general
+practitioner for the very moderate fee that must obtain in a pre-nuptial
+examination compelled by law. If it or the serum test for gonorrhea are to
+be applied then the legislative body of the state will find it necessary
+to establish a special public laboratory or laboratories for their
+application. This, however, is not a matter of particular difficulty and
+would be capital well invested in any state.
+
+=The Perils of Venereal Disease Must Be Prevented at Any Cost.--=However,
+no matter what the cost may be to the state, no matter what the exaction
+from the individual, the grave perils of venereal disease to society
+_must_ be prevented. We owe it to the cause of humanity that there be
+fewer victims born into a world of eternal night, that from a parentage of
+polluted blood there spring no longer hosts of children with feeble
+misshapen bodies or with tarnished intellects, death-marked at the door of
+life.
+
+=Bad Environment Can Wreck Good Germ-Plasm.--=In conclusion it is evident
+from our discussion of prenatal influences that not all of being well-born
+is concerned with heredity in its proper sense, since the unborn young may
+be influenced either directly or indirectly by environmental conditions
+which are in no sense products of heredity, although as far as the
+immediate child is concerned the result may be quite as disastrous where
+the influence is a baneful one. As to the production of beneficial
+prenatal effects, while parents can do nothing toward modifying favorably
+such qualities as are predetermined in their germ-plasm, nevertheless they
+must come to realize that bad environment can wreck good germ-plasm. They
+can see to it that they keep themselves in good physical condition by
+wholesome temperate living, and thereby insure as far as possible healthy
+germ-cells for the conception and good nutrition for the sustenance of
+their progeny. Their one sacred obligation to the immortal germ-plasm of
+which they are the trustees is to see that they hand it on with its
+maximal possibilities undimmed by innutrition, poisons or vice.
+
+
+
+
+CHAPTER VII
+
+RESPONSIBILITY FOR CONDUCT
+
+
+Since both physical and mental attributes are unquestionably inherited, it
+becomes a matter of importance to inquire into the nature of the entity we
+call personality. To what extent is human conduct a product of parentage?
+Although apparently free agents are we in reality only by infinitely
+subtle indirections making the responses, forming the habits, establishing
+the characters which result merely from the blind impulsions of an
+inherent constitution? If so, who is praiseworthy, who blameworthy? Are
+men
+
+  "But helpless pieces of the Game He plays
+  Upon this chequer-board of Nights and Days."
+
+=All Mental Process Accompanied by Neural Process.--=Whatever the ultimate
+decision of psychologists may be regarding the relation of mind to the
+sensory and nervous mechanism of man it is certain that there is so close
+an association between them that the least alteration in the mechanism
+means a parallel effect in the mind, or in the words of Huxley, "every
+psychosis is definitely correlated with a neurosis." The rind or _cortex_
+of gray matter which constitutes the surface of the large cerebral
+hemispheres of the human brain is regarded as the seat of consciousness.
+The development of the mental powers in the infant is dependent on the
+development of the elements of this cortical substance and the waning of
+the mental faculties in old age goes hand in hand with its atrophy.
+Abnormal arrangements, injuries or omissions in it mean mental
+unsoundness. How the activity of the structural mechanism gives a reaction
+in consciousness is not understood, but we know that in the living being
+the two phenomena are inseparably linked. Whether we accept the hypothesis
+that consciousness is an actual product of the structural mechanism or the
+hypothesis that the latter is only an instrument for the manifestations as
+consciousness of an outside force or entity, just as the telegraphic
+instrument manifests the existence of electricity, is neither here nor
+there for our purposes. On either supposition the degree and manner of
+expression are determined by the structure of the mechanism. Our main
+problem is to decide as nearly as possible how much of the mechanism is
+rigidly inherited, how much is at birth largely undestined, so that its
+ultimate outcome is in part a product of the forces which play upon it, or
+in other words of education and training.
+
+=Gradation in Nervous Response from Lower Organisms to Man.--=To
+comprehend fully the basic nature of human neural responses one must seek
+the roots in the behavior of lower organisms. For there is found in a
+simpler form many of the fundamental activities and the first dim gropings
+which emerge in man as memory, reason and will. As we ascend the scale of
+animal life we find a continuous advance in neural complexity and nervous
+response that in many respects grades up closely to the human type.
+
+A windmill or a weather-vane points toward the source of the wind,
+obviously not because either exercises any special choice in the matter,
+but because it is constructed on such lines of symmetry that when the wind
+strikes it, if it slants the slightest to left or right, the more exposed
+surface receives the greatest pressure and thus swings the body back into
+the line of least resistance.
+
+=Behavior of Many Animals Often an Automatic Adjustment to Simple External
+Agents.--=It is a far cry, of course, from the responses of such a machine
+as a windmill to the responses of even the simplest living thing, but in
+spite of the broad gap between the two, there is much reason to believe
+that the behavior of many living organisms is due in a marked degree to
+the directive effects of comparatively simple external factors rather than
+to the complex internal volitions the casual observer is likely to
+attribute to them.
+
+=Tropisms.--=It is a marked characteristic of all living protoplasm that
+it has the power of responding to external stimuli. This power of response
+is termed _excitability_ or _irritability_. In describing the motor
+responses of living organisms to stimuli resulting from a change in
+surroundings the term _tropism_ (Gr. _Trope_, turning) is frequently used
+and the kind of stimulus is indicated by a prefix. Thus the term
+phototropism means a turning or _orientation_ brought about by means of
+light. An organism which reacts by a movement toward the source of light
+is said to be _positively phototropic_, one which moves away from it,
+_negatively phototropic_. By using such a neutral terminology the
+physiologist avoids implying that necessarily "likes" or "dislikes" or any
+other psychic reaction enter into the movements.
+
+Several kinds of tropisms are recognized, such as _phototropism_ or
+_heliotropism_, reaction to light; _thermotropism_, reaction to heat;
+_electrotropism_ or _galvanotropism_, to electric current; _geotropism_,
+to gravity; _chemotropism_, to a chemical; _rheotropism_, to current;
+_thigmotropism_ or _stereotropism_, to contact; and _chromotropism_, to
+color.
+
+=Many Animals Show Tropic Responses.--=Many of the lower animals seem to
+have their movements determined more or less mechanically by the action of
+such external factors, some being positively, others negatively responsive
+to a given kind of stimulus, or the same individual may be at one time
+positive, at another negative, according to modifying conditions to be
+mentioned presently.
+
+In plants and in simpler lower animals there is no special nervous system.
+The responses of these organisms depend on the general irritability of
+their constituent protoplasm. In other animals a nervous system is
+developed, crude and diffuse in lower forms, extremely delicate, complex
+and definitely ordered in higher forms. But it should be borne in mind
+that nerve protoplasm possesses only in high degree a capacity for
+irritability, conduction, etc., that is common to all living substance. In
+keeping with other "physiological divisions of labor" or specialization
+which mark the increasing complexity of animals, this enormously enhanced
+sensitivity and conductivity of certain tissues have come about, and they
+have become set apart for these special functions. In higher animals,
+therefore, the tropisms where operative must act more or less through the
+agency of the nervous system instead of directly through the general
+protoplasm of the organism.
+
+=Certain Apparently Complex Volitions Probably Only Tropisms.--=Where
+nervous systems enter into tropic responses there must be specific
+sensibility of certain nerve terminations (i. e., sense organs) at the
+surface of the body. These sensory or receiving nerves connect through the
+central system with corresponding motor nerves which in turn supply
+certain specific muscles through the contraction of which the organism is
+as surely and as mechanically oriented as in the simpler cases. For
+example, if light is the stimulating agent, when it strikes a positively
+phototropic animal, if the latter is not already oriented, the eyes or
+other nerve terminations sensitive to light transmit an impulse through
+the central nervous system to certain muscles causing them to increase
+their tension and thereby swing the animal around with its head toward the
+light. Progressive movements which the organism then makes must carry it
+toward the source of light. Thus it is not "love of light" that draws the
+moth into the flame but the mechanical steering of the body toward the
+source of light through the stimulations produced by the light waves. It
+is chemotropism, not solicitude for its offspring, which drives the flesh
+fly to lay its eggs on decaying meat. And it is stereotropism and not a
+desire for concealment which impels certain animals such as many worms
+and insects to get into a close contact with solid bodies, or in other
+words to "hide" themselves in burrows and crevices.
+
+=Complicating Factors.--=However, beautifully as these theories of
+tropisms work out in a broad general way, there are various additional
+factors entering which must be reckoned with, and these become more
+numerous and of more consequence as the organism becomes more complex. In
+the first place certain internal conditions must be considered. Living
+matter is characterized by its instability. There are continual synthetic
+and disruptive processes in progress which the physiologist terms
+metabolic changes. The very "life" of such matter seems to be the
+manifestation of such changes. Concerning what the ultimate source of
+these changes is, whether or not indirectly they may be referred to
+external conditions as seems probable to many biologists, no one so far
+has ever given a convincing, positive answer. It is sufficient for our
+purposes to know that they may have set up certain internal stimuli which
+may modify the behavior of the organism in which they reside, and that the
+"physiological state" of the organism at the time of external or internal
+stimulation will condition the response. This physiological condition may
+be dependent on the general metabolic equilibrium of the animal, or on the
+extent of previous stimulation by means of the same or different agents.
+Thus the organism may not always react in the same way to the same
+stimulus.
+
+The intensity of the stimulation and change in the intensity of the
+stimulation, are also factors to be reckoned with. Moreover, it must be
+taken into account that a given organism is often operating under the
+control of more than one external influence. For example, swarm spores in
+a dish of water which at a given temperature are positively phototropic,
+that is, gather at the side of the dish toward the light, may, if the
+temperature of the water is raised or in case of marine forms if the
+salinity is increased, become negatively phototropic. Sometimes two or
+more forms of stimuli may cooperate in bringing about certain behavior as,
+for instance, in the reaction of the earthworm to a suitable habitat,
+through a combination of chemical and contact stimuli. On the other hand,
+two different stimuli may interfere with each other; for example, the
+usual phototropic responses of certain animals do not manifest themselves
+when they are mating or feeding. In short, anything that alters the
+physiological state of the organism may cause it to react in a different
+manner. And thus with the interplay of shifting external agents and
+variable internal state the bounds of behavior on these purely mechanical
+bases become considerably extended.
+
+=Many Tropic Responses Apparently Purposeful.--=The query arises as to why
+if these responses are mechanical they are so often apparently purposive;
+that is, why do they so often subserve some useful end for the animal?
+While they do not always work out to the animal's benefit, as for instance
+in the case of the moth and the light or under many other conditions that
+can be devised experimentally, as a matter of fact under normal natural
+conditions they are on the whole useful to the organism, carrying it
+into suitable surroundings of food, lessened danger, temperature, and the
+like.
+
+The probabilities are that in their first origin the reactions were not
+purposive. However, if any proved harmful they would result in the
+extermination of their possessors and hence of that particular strain of
+individuals. Those types that happened to have useful reactions would be
+left and in course of time as the process of eliminating the others went
+on, would become the prevailing types. Any organism which the useful
+reaction had preserved would tend to hand it down to the succeeding
+generation where again it would be the conserver of those individuals
+which possessed it in sufficient degree.
+
+=Authorities Not Agreed on Details of Tropic Responses.--=Although all the
+foremost modern students of animal behavior accept as facts the more or
+less mechanical orienting effects of external stimuli, there is by no
+means unanimity of opinion regarding details. Some stress as the directive
+factor the continuous action of the stimulating agent on sensitive tissues
+symmetrically situated. Others would maintain that it is the time rate of
+change in the intensity of the stimulating agent, or that the factor is
+different in different cases. Some make much of an automatic sort of
+"trial and error" system by which certain organisms test out an inimical
+environment until the path of least irritation is hit upon as the way to
+safety. The field is a broad one and to get at the finer shades of
+distinction the reader will have to refer to the works of such
+authorities as Loeb, Jennings, Holmes and Mast.
+
+=Tropisms Grade Into Reflex Actions and Instincts.--=The tropisms in many
+cases become indistinguishable from _reflex actions_ and these in turn
+grade up into the _instincts_ of animals. The latter may be looked on as
+but subtler and more involved reactions made possible through a more
+intricate structural organization. As might be expected of instincts, the
+feature of utility is more in evidence than in simpler tropisms because
+they have become of proportionately greater magnitude, but the same
+fundamental mechanism is apparently at bottom of both. It has already been
+seen how the "instinct" of the blow-fly to lay its egg on meat is
+interpretable as a chemotropic response. Thus no elaborate psychic
+mechanism is necessary in such behavior.
+
+=Instincts.--=In the typical instinct there is a series of "chain
+reflexes" in which one step determines the next until mechanically the
+whole gamut of changes is run to the last step. It is characteristic of a
+purely instinctive act that an animal performs it without practise,
+without instruction, and without reason. Moreover, all of the same kind of
+animals tend to perform the act in the same way. But with instincts, as
+with tropisms, the physiological state of the organism must be regarded.
+For instance, the instinctive reactions of an animal sated with food or
+hungry will be different.
+
+=Adjustability of Instincts Opens the Way for Intelligent Behavior.--=As
+we progress in the scale of animal life this adjustability of instincts
+to new conditions comes more into evidence. While prescribed in the main
+by internal impulse the carrying out of the action is capable of some
+adaptability to circumstances. And in proportion as this adaptability
+releases the organism from a blind rigid working-out of a predetermined
+end, there is opened up the possibility of intelligent behavior; that is,
+of modification of the instinctive behavior by individually acquired
+experience.
+
+While the generation of instinctive impulses still occurs it is left more
+for individual experience to teach discrimination between ends. But we can
+not escape a fundamental structural mechanism, for with this new capacity
+of educability must come new structural mechanisms in the nervous system
+and this must be as faithfully reproduced in each individual as is the
+basis for any other nervous response. How low in the scale of animal life
+animals can profit from their experiences to the extent that their future
+conduct is conditioned thereby is not known. Some would place it as far
+back as the protozoa, others would not. Where such modification of
+behavior is possible there must be some mechanism for the storage of
+impressions in the form of what we term _memory_.
+
+=Modification of Habits Possible in Lower Animals.--=Among invertebrates
+such animals as crayfish will acquire new habits, or rather will modify
+old ones. Even as lowly an organism as the starfish can have changes of
+habit thrust on it. When a starfish is placed upon its back it rights
+itself by means of its arms or rays. Professor Jennings found that in a
+given individual the tendency was always to employ certain rays for this
+rather than others. However, by preventing the use of the rays customarily
+employed, he found that the animal would use a different pair and that
+ultimately in this way it could be trained into the habit of using this
+pair of rays even when restrained in no way. One starfish which was given
+one hundred eighty such lessons in eighteen days after an interval of
+seven days still retained the new habit; young individuals were found to
+be more easily trained than old ones.
+
+=Some Lower Vertebrates Profit by Experience.--=Among vertebrates it is
+known that those as low in organization as fish will profit by experience.
+They will learn to come for food at a regular time and apparently learn
+more or less to appreciate the presence of certain obstacles with which
+they have had unsatisfactory experiences. Professor Sanford sums up what
+he believes are the limitations of the piscine mental organization as
+follows: "No fish is ever conscious of himself; he never thinks of himself
+as doing this or that, or feeling in this way or that way. The whole
+direction of the mind is outward. He has no language and so can not think
+in verbal terms; he never names anything; he never talks to himself; as
+Huxley says of the crayfish, he 'has nothing to say to himself or any one
+else.' He does not reflect; he makes no generalizations. All his thinking
+is in the present and in concrete terms. He has no voluntary attention, no
+volition in the true sense, no self-control."
+
+=Rational Behavior.--=Finally, however, out of these first dull
+glimmerings of intelligence as exemplified in the higher invertebrates
+and the lower vertebrates, which can modify behavior as the result of
+experience, come the still higher factors so dominant in man, of
+_rational_ behavior. This higher mental process can realize the end to be
+reached and can deliberate on the means to be employed. By means of his
+_reason_ man can overcome difficulties in advance by "thinking" out
+suitable schemes of action. Some naturalists believe that man stands alone
+in possessing the power to reason, although others believe that some of
+the other mammals, notably the other primates, possess the same attribute
+although in a much less degree.
+
+=Conceptual Thought Probably an Outgrowth of Simpler Psychic States.--=Is
+the capacity for such conceptual thought, however, which appears as the
+final efflorescence of complex neural activity something entirely new?
+Most students of comparative psychology maintain that it is not. Just as
+one kind of an instinct frequently grows out of another, so has this grown
+out of the complex of _psychic_ states which preceded it. It apparently is
+the product of the increasing awareness on the part of animals of their
+neural processes and the outcome of these processes, which becomes more
+and more prominent as we ascend the scale of animal life. With the advent
+of associative memory the mind comes more and more to deal with attributes
+of objects instead of merely with each single concrete object as it
+presents itself, and these attributes being common to many objects, come
+to represent definite ideas which can be manipulated by the mind.
+Language, of course, has been an indispensable aid to man in this regard,
+for words become descriptions of facts and symbols of concepts, and
+thereby allow of abstract thought.
+
+=The Capacity for Alternative Action in High Animals Renders Possible More
+Than One Form of Behavior.--=With this modification of instinct by
+experience made possible, there comes at the same time, of course, the
+capacity for a rational instead of a purely instinctive behavior. This
+very capacity for alternative action opens up many new possibilities of
+behavior and together with the well-known fixative effects of habit, also
+the opportunity of permanently establishing certain ones. Thus it is
+obvious that a behavior toward which in a strict sense there can not be
+said to have been an original specific tendency, can be developed. What
+was present in the first place was only a general possibility of the
+development of any one of several types of behavior. The final choice of
+the alternatives together with repetition makes it the habitual behavior
+of the individual. Of course it can be urged that if the selection of the
+type of behavior is left to the individual then the latter will operate
+automatically toward the various impulsions of its neural make-up and one
+path will be followed because of stronger inclination in that direction,
+so that the whole procedure is in the end the mere operation of an
+automaton. But however this may be in the individual left to itself, the
+fact is in man that the young individual is never left to itself and in
+the nature of things can not be, so that without entering into this
+troubled pool of controversy regarding freedom of the will, I wish merely
+to point out that the possibility of more than one form of behavior
+exists and that if one is more desirable than the others then this one can
+be chosen by the ones responsible for the training of the young individual
+and clenched fast by the agency of habit.
+
+Intelligence, reason and habits, however, no less than instincts and
+tropism must have neural as well as psychical existence and we can not
+escape therefore the underlying mechanism.
+
+=The Elemental Units of the Nervous System Are the Same in Lower and
+Higher Animals.--=It is interesting to note that the fundamental neural
+mechanism which underlies the mental processes of higher animals is not
+essentially different from that which serves in lower forms. Although as
+animals become more complex their nervous systems have become
+proportionately larger and incomparably more intricate, still all the
+changes have been rung on the same basic neural unit, the _neuron_ or
+nerve-cell (Fig. 32_A_, p. 209). The higher nervous system differs from
+the lower in the number, in the specializations and in the associations of
+these units rather than in possessing something of entirely different
+elemental structure.
+
+=Neuron Theory.--=According to the prevailing modern conception the entire
+nervous system is made up of a series of units called _neurons_. Each
+neuron is a single cell with all its processes. The latter consists
+typically of short branching processes on the one hand, known as
+_dendrites_, and of a single process on the other, known as the _axon_,
+which extends from the cell to become a nerve fiber (Fig. 32, p. 209). The
+various neurons, with possibly a few exceptions, are not anatomically
+continuous but contiguous. They communicate with one another apparently by
+contact only. The axon of each neuron ends in an elaborate series of fine
+branchings which lie in contact with the dendrites of another neuron, or
+in some cases with the body of the other cell (Fig. 32, p. 209). Thus the
+nervous impulse passes from one neuron to the other at these points of
+contact. An impulse is supposed to travel normally only in one direction
+through a neuron, the dendrites being the receiving and the axon the
+discharging terminals. There are various types of neurons. Some,
+particularly within the brain, have their main processes so provided with
+branches and brushes that they may come into physiological connection with
+a number of other neurons.
+
+
+[Illustration: FIG. 32
+
+A--Diagram to illustrate neurons and their method of connection; _a_,
+axon; _d_, dendrite; _s_, synapse. To simplify the diagram the medullary
+sheathes of such fibers as would have them have been omitted. The arrows
+indicate the direction in which the impulse travels. The lower series
+shows diagrammatically how from the same neuron in the cortex two
+subordinate neurons may be affected, the one excited to cause contraction
+of a certain group of muscle fibers, the other inhibited so that the
+antagonistic fibers may relax and thus not hinder the movement of a given
+part.
+
+B--Section of a region of the cerebral cortex (after Cajal). The cells
+have been blackened with chrome-silver and are much less highly magnified
+than the diagrams in A. The numerals refer to certain characteristic
+layers of the cortex in this region.]
+
+
+=Establishment of Pathways Through the Nervous System.--=It is believed
+that more or less resistance to transmission of stimuli prevails at the
+point of contact (_synapse_) between two neurons but that this resistance
+is lessened by repetition of conduction. The frequent traversing of a
+given pathway by similar impulses finally results in an automatic
+occurrence of the transmission, or, in other words, the action becomes
+habitual. Education consists largely in establishing such routes through
+the nervous tissue. Because of the greater plasticity of the neural
+mechanism in youth it is easier to open up and fix pathways of conduction
+than in later years. Moreover the earlier established lines of conduction
+become the more permanent.
+
+=Characteristic Arrangements of Nerve Cells Are as Subject to Inheritance
+as Other Structures of the Body.--=That the main features of the nervous
+system are inherited becomes obvious when we see that each kind of animal
+has its own distinctive numbers, arrangements and proportions of the
+various neural units. In man, for example, there are certain
+characteristics, types and groupings of nerve-cells which are reproduced
+generation after generation with remarkable fidelity. This means that in
+so far as these represent the mental make-up of the individual, his
+mentality is continuously linked with others which have gone before. The
+new-born child has all the nerve-cells in its brain that it will ever have
+but the ultimate linkages of the finer connectives between them, or at
+least the pathways of travel, remain in large measure to be made.
+
+As we have already seen, the cerebral cortex is the seat of the chief
+mental faculties of man or at least of the highest of these. Professor
+Lloyd Morgan, one of our greatest authorities on comparative psychology,
+is inclined to believe that the instincts are located in the subcortical
+material. In any event, the inheritance of mental ability resolves itself
+into the inheritance of a certain cerebral mechanism.
+
+=Different Parts of the Cortex Yield Different Reactions.--=The cerebral
+cortex, however, is not functionally homogeneous throughout. Certain
+regions have been shown to be motor, others sensory, and moreover, these
+regions are apparently further specialized so that a given one of them is
+associated with a specific type of sensory or motor response, not merely
+with responses in general. Thus by injuring one of the sensory areas we
+might destroy vision but not other sensations, or by stimulating one of
+the motor centers we would get a response in a corresponding motor organ
+but not in all such organs. Likewise, it is probable that still different
+areas, the so-called "association areas," relatively of much greater
+development in man than in any other animal, are the regions in which
+various perceptions and conceptions are synthesized and formed into
+organized knowledge. Here also are engendered the volitions which when
+flashed through the motor centers become expressed in activity or
+behavior.
+
+It seems highly probable that just as the sensory and motor areas differ
+in kind from one another, so we must suppose there are qualitative
+differences in various parts of the association areas so that the
+different parts give different reactions in consciousness; that is, each
+special mental ability of the individual is more or less centered in a
+special part of the cortex. And just as there may be variations in other
+structures of the organism so there may be variations in these areas. The
+"gifted" person in some one direction, whether it be in mathematics,
+music, painting, or what not, is on this hypothesis one who has that
+particular area of his brain which forms the basis for the talent in
+question more highly developed than it is in the average individual. And
+since such talents are handed down to descendants, this can only mean that
+a similar grouping of the neurons in the region in question has occurred.
+
+=Skill Acquired in One Special Branch of Learning Probably Not Transferred
+to Another Branch.--=Such a differential arrangement of the
+brain-mechanism which presumably underlies the various mental abilities
+would lead to the inference that skill in one special branch of learning,
+in so far as it involves only certain centers of the cortex, would not be
+transferred to another branch based on different neural pathways and
+centers. Development of historical knowledge, for example, would not
+enhance one's mathematical ability, or vice versa. The testimony of
+various psychologists bears out this idea. In so far as certain factors of
+training, such as habits of industry, concentration, etc., are common to
+the study of either mathematics or history, the good effects of either
+discipline will probably be much the same, but the identity of effect
+vanishes as soon as the intrinsic characteristics of the subjects
+themselves are involved.
+
+Just how far we are warranted, however, in carrying this idea of localized
+functions as regards the association areas is a moot question. Our present
+attitude regarding the specificity of such localizations is largely a
+matter of inference based on analogy to conditions which obtain in other
+and better known parts of the brain, together with the indubitable
+differences in inborn abilities which exist between individuals. Some few
+brain physiologists maintain that the whole cortex operates more or less
+as a unit in all of the higher psychical activities.
+
+=Preponderance of Cortex in Highest Animals.--=One of the most interesting
+conditions in the nervous system of the highest types of animals is the
+way in which the cortex has outrun the other parts of the brain in size
+and complexity and has come to dominate the organism more and more both
+directly and indirectly. Aside from the proportionately greater increase
+in size of the cortex, there is an abundance of anatomical evidence of
+this altered and probably altering system of control in man and the higher
+apes. This is well illustrated in the fiber tracts (nerve bundles) of the
+spinal cord.
+
+=More Long Fiber Tracts in the Spinal Cord of Man.--=The spinal cord
+although having many nerve centers of its own is also in great part a
+large cable for conducting enormous numbers of fibers from one part of the
+cord to another, or to and from the brain. In man and the higher apes a
+considerably larger percentage of the total area of the cord is given up
+to the long fiber tracts from the brain to the body than in lower
+vertebrates. This progressive increase in long fiber tracts in the higher
+anthropoids probably marks more and more domination of the body by the
+higher brain centers and correspondingly less by the direct activity of
+the cord and by the lower brain centers. However, even in man, many of the
+simpler reflexes of the body still have their centers in the spinal cord.
+
+=Special Fiber Tracts in the Cord of Man and Higher Apes.--=There are
+certain special tracts of the cord that are particularly interesting in
+connection with the increasing domination of the brain over the body,
+namely, the _pyramidal tracts_. These were the latest tracts to appear in
+the animal kingdom and are apparently the latest to become functional in
+the individual. It is believed that the development of the medullary
+substance (an enveloping sheath) of the common medullated nerve fiber
+marks the time of entrance of the fiber into activity and it is a
+significant fact that the formation of this sheath occurs last of all in
+the fibers of the pyramidal tracts, where it does not appear till after
+birth. These tracts convey impulses from the brain to the body. They
+consist of two sets of tracts, in fact, one the crossed, the other the
+direct. As an anomaly, probably arising most frequently from instrumental
+injury at birth, the pyramidal tracts fail to develop normally, with the
+distressing result that the infant, although possessing perfectly normal
+brain activity and normal spinal cord reflexes, is unable to exercise
+voluntary control of the body. In other words the condition, like
+hare-lip, is one of suppressed development. At least this seems to be the
+most plausible explanation of what is known as _Little's disease_. Such
+unfortunates usually die early although they may survive for a few years.
+
+The direct pyramidal tracts occur only in man and man-like apes. They vary
+considerably in extent in different individuals. They originate in nests
+of characteristic large cells located in the cerebral cortex and are
+regarded as paths, though not the only ones, through which volitional
+impulses are conveyed from the brain. They seem to control certain of the
+finer and more delicate movements of the body.
+
+=Great Complexity in Associations and More Neurons in the Brain of Man
+Than of Other Animals.--=It has already been noted that as animals stand
+higher in the scale of life while the general plan of their neural
+elements remain the same, there is increasing complexity in the number and
+connections of the neurons. The number of processes on individual
+nerve-cells is also greater. There is in fact much greater complexity in
+the number of processes and the inter-connections of the neural cells
+than in the numbers of the cells themselves. This would seem to indicate
+that the greater mental activities of higher animals depend more on
+richness in complex associations than on mere increase in number of
+neurons. The latter, however, is by no means unimportant as may be seen in
+man, for instance, in whom it is estimated that the cerebral cortex, that
+is, that part of his brain in which his more complex mental processes
+transpire, contains some nine billion more nerve cells than does the
+corresponding region of the brain of an anthropoid ape.
+
+Of especial significance in the psychic make-up of man is his vastly
+increased capacity for inhibition. Although not possessed by all men in
+equal measure and not entirely wanting in lower animals it is a
+distinctive feature in all human conduct. Much of any child's education,
+particularly as it pertains to behavior, must be concerned with training
+in the exercise of proper inhibitions. He must learn to suppress certain
+primitive types of reaction in favor of higher ones. This applies not only
+to motor activities but to trains of thought as well. The essence of
+self-control consists mainly in ability to substitute for one impulse or
+idea other compensating ones. And the secret of concentration lies in
+being able to banish irrelevant ideas and focus on the central thought.
+
+=The Nervous System in the Main Already Staged at the Time of Birth for
+the Part It Must Play.--=It is clear from what is known of its anatomy
+that in the main the central nervous system is framed to respond in
+certain set ways, that there are determinative elements in it which
+control or determine the responses, and therefore the behavior of the
+body. The same evidence shows also, however, in the incompleteness of many
+of the associations, that while the stage is all set and some of the main
+features of the performance are determined at the time of birth,
+considerable yet remains to be done toward fitting the parts together and
+working up the detail. Just exactly what and how much is rigidly
+determined no one knows.
+
+=Many Pathways of Conduction Not Established at Birth.--=As we have
+already seen the evidence is that many of the neural pathways are not yet
+fully established at birth, and there is some indication that routes once
+opened may be altered. To what degree this has bearing on behavior is
+still unknown, but since neurologists attribute so much importance to the
+richness and the associations of the cell-outgrowths, it is evident that
+this increase in the number of pathways after birth with possible
+alternatives of connections may be a very important factor in the
+modification of behavior. Yet, on the other hand, we are completely in the
+dark as to what extent these later associations are predetermined in the
+earlier cells.
+
+=The Extent of the Zone That Can Be Modified Is Unknown.--=There is little
+doubt that many of the paths of action are already firmly established.
+Others, although not irrevocably fixed, offer the least resistance and
+would "naturally" be taken if not counteracted or modified by the more or
+less artificial development and fixation of other paths through
+cultivation and habit. Yet others perhaps are largely neutral; they still
+await the initial decisive push which "choice" or external environment may
+mete out to them. As trainers of youth all that is left that we can do is
+to attempt to develop in certain ways the elements of this indefinite,
+impressible zone. Unfortunately, we must labor in the dark to a great
+extent as we have all too little indication of which the malleable factors
+of intellect and conduct are. We can only infer from long, intelligent and
+sympathetic observation of children in successive stages of their
+development. It is only by having clearly in mind the nature of our
+problem that our conclusions will finally come to be of enhanced practical
+value in the training of children. Observation to the present time clearly
+indicates that many children are strongly predisposed this way or that "as
+the sparks fly upward."
+
+This is a point too frequently overlooked by educators. They are often
+unduly actuated by the other piece of the truth that, "as the twig is bent
+the tree inclines." They sometimes fail to realize that after all the tree
+remains the same kind of a tree. If an apple tree, while it may be bent
+from the normal path of development, it can not produce other fruit than
+apples. Just how much the destiny of man can be influenced by training and
+the exercise of his own will power is the fundamental question not only of
+pedagogy but of ethics as well. For if man's rational judgments are
+markedly conditioned by his neural make-up then the volitional judgments
+which underlie conduct are likewise conditioned since they are
+inextricably intermingled with his reason. We must believe that to a
+considerable extent emotional expression, as well as other mental
+functions, is due to hereditary dispositions of the neurons in the
+various parts of the brain.
+
+=Various Possibilities of Reaction in the Child.--=Despite the innate
+predeterminations of the tree, it is nevertheless our province to see that
+the twig _is_ bent, but our work can only be done with due intelligence
+when we recognize something of the limitations of our material. Of the
+various possibilities of reaction we must see that certain desirable ones
+are realized, even, in some cases, if only to have others thereby
+excluded. It is a commonplace of psychology that all cerebral excitations,
+no matter what the origin, must vent themselves in some way and if this
+expression is not directed into proper channels it will very likely find
+improper ones. We must see that the young wearer of the coat of
+undetermined capacities gets it set by repeated performance into the
+habitual wrinkles of normal social conduct. For it is a trite observation
+that when habits are once well established it requires tremendous efforts
+to do otherwise than as they dictate. There is not the least doubt that
+some of our subjects will respond much more readily to training in certain
+directions of habitual reactions than others, but we have always the
+consolatory knowledge that no matter how difficult the art may be at
+first, repetition reduces the difficulty.
+
+While much of any youth's character must be determined by external forces
+brought to bear upon it, the ultimate climax of our effort and measure of
+our success will be the extent to which we have engendered in him the
+capacity for initiating and carrying out through his own volition those
+impulsions and inhibitions which tend to the highest good of humanity.
+
+=Probable Origin of Altruistic Human Conduct.--=Those phases of human
+conduct which find expression in consideration for others seem no less
+than other mental attributes to have their origin in certain fundamental
+instincts. Altruistic conduct, in last analysis, apparently resolves
+itself back largely to certain very fundamental impulsions, namely those
+which arise out of certain obligations for the welfare of others which are
+necessarily associated with the marital, parental and filial relations
+that must exist where the young require post-natal care. Looked at from
+the standpoint of natural selection, this would come about as a mere
+matter of survival value. Where the young, as in man, are helpless for a
+long period of time, more opportunity would be afforded for the
+development of both conjugal and filial affection. The sympathetic
+emotions once established in such family relations would partly through
+habit, partly through community of interest, readily become extended to
+clan or tribe and as a final consummation to all mankind.
+
+=Training in Motive Necessary.--=In the training of children, then, we
+must recognize first of all that there are decided inclinations or bents
+which, as long as they are not anti-social in nature, must be respected if
+not always encouraged. While it is necessary to utilize these as much as
+possible in their training still we must bear in mind that although it is
+natural for a child to follow certain interests, the fact remains that as
+regards social worth these natural interests may not be the most valuable.
+When this is true we must strive to develop others which will compel
+attention and thus become impelling factors in conduct. Where certain
+fundamental impulsions run contrary to the common welfare it is necessary
+to practise the child in the setting up of inhibitions or counter-impulses
+until this becomes habitual. He must be led to construct a protective
+mantle of appropriate scruples, doubts and fears. It is all important to
+get the proper motives for action to prevail in his mind.
+
+=Actual Practise in Carrying Out Projects Is All Important.--=But on the
+other hand it is equally important to see that the action is effectively
+carried out. In the matter of self-discipline, particularly, we may have
+many ideal impulses and realize that they should prevail over certain of
+our natural propensities, but unless we put forth effort to overcome the
+propensities our ideal impulses are of no avail. The world has many such
+moral paralytics to-day who can not seize their "languor as it were a
+curling snake and cast it off." It is training in this very overcoming of
+reluctance, in this putting forth of actual effort toward worthy ends
+instead of merely memorizing precepts about the desirability of such
+accomplishments, that is so sadly lacking in our school and home life
+to-day. We prate of the importance of self-control, we say with our lips
+that the way to learn to do is by doing, we proclaim that it is more vital
+to instil good mental and physical habits into our pupils than to stock
+them with information, we preach that mere fact training is as conducive
+to making a first-class rascal as an upright man, yet we jog on
+complacently in the well-beaten ruts of memory routine which require the
+memorizing of symbols rather than real understanding. We seldom require
+that our proteges make intelligent judgments based on evidence, we rarely
+exact of them decisions in matters of ethics, and almost never demand that
+they put their knowledge into efficient accomplishment. It can not be too
+strongly urged that we need less of formulae learned by heart, less dead
+erudition pigeonholed in the brain like so many foreign bodies, and vastly
+more assimilation of knowledge into the living personality of the
+individual.
+
+Where in school or home to-day do we find provision for such training? Our
+tendency is, in fact, just the opposite. According to the modern code, as
+it works out in many instances at least, the child must be taught through
+play. Though it is a truism that he who has not learned obedience can
+never be master of himself, the child of to-day must not be made to obey
+but be wheedled into changing his mind. If a given subject of study proves
+distasteful to him, the fault is the teacher's for not making it
+interesting, for he must always be led on by the thrill of fascination. In
+other words, the child must not only be allowed but be encouraged to take
+the path of least resistance. His own pleasure is to be the standard of
+his actions. Let no stern demands of duty interfere!
+
+Is it any wonder that the products of such tutelage come into the
+activities of life self-indulgent and undisciplined, and although often
+recognizing our private and public shame in business, politics and
+conduct, still remain supine, evasive of the unpleasantness or hardships
+of reform, or inefficient or unwilling in accomplishing unselfish ends?
+
+=Interest and Difficulty Both Essential.--=The writer does not wish to be
+understood as minimizing the importance of interest on the part of the
+child in what he is doing. Interest is undeniably the open sesame to
+desirable mental development; but what he does protest against is that not
+uncommon interpretation of interest which deems it necessary to eschew
+most serious consideration of a subject and evade such parts as present
+difficulties. Certainly if there is any fact that stands out prominently
+in human experience it is the fact that nothing conduces to the
+development of moral stamina so much as the overcoming of difficulties,
+particularly distasteful difficulties.
+
+=Conduct Developed Through Actual Performance.--=Self-control and the will
+to do can be trained and crystallized into habit as well as can any other
+activity. It is a fact that one well grounded in morals by habit will
+successfully resist subconscious impulsions to wrongdoing even when
+suggested in the hypnotic state. Conduct is largely a matter of growth
+through actual performance. For proper guidance of this growth there must,
+of course, be high ideals around which the feelings are led to cluster and
+by which they gradually come to be controlled.
+
+=Construction of Ideals.--=The construction of such ideals through
+example, through precept, through appeal and through actual practise in
+self-denial and self-control on the part of the child, should be the
+foremost duty of the parent or teacher. Above all it should be remembered
+that imitation of teacher, of parents, of companions, is more of a factor
+than intellect in the moral action of children. At present educationally
+we are in a fever for vocational training, for "practical" work, and in
+general for all things conducive to coaching our pupils in how to make a
+living, yet commendable as all this may be, is it not of even more
+fundamental importance to train them how to live?
+
+=The Realization of Certain Possibilities of the Germ Rather Than Others
+Is Subject to Control.--=It may be said in a sense that there exists
+potentially in any germ all the things that can possibly come out of it
+under any obtainable conditions of environment. The very initiation of a
+given mode of expression by some environmental factor, however, often
+mutually excludes many of the others. We get a given average result
+ordinarily because development normally takes place in a given average
+environment.
+
+As may be easily shown by experiment, this is manifest even in the
+instincts of lower animals. In the young the various instincts do not come
+into expression at the same time, and it not infrequently happens that if
+one of the earlier instincts becomes operative toward certain objects or
+situations, later instincts will have a wholly different relation toward
+these objects or situations than they would otherwise have had. As a
+result the whole life conduct of the animal is markedly modified. For
+example, young animals immediately after birth have no instinct of fear.
+They do, however, have a strong instinct to attach themselves to some
+moving thing and follow it. The utility of such an instinct, as for
+instance in the case of young chickens, is obvious. The object of
+attachment is usually the parent, but man may take the place of a parent
+and the young animal will fearlessly follow him about. However if the
+young animal has had no experience with man during its earliest infancy a
+later instinct, that of fear or wildness, will have come into play and it
+will flee from him. It is clear, therefore, that by familiarizing the
+young animal with man before its instinct of fear has come to expression,
+certain habitual reactions are set up in it which inhibit or limit the
+application of its instinct of wildness as regards man. In other words,
+the whole course of its life has been altered by this simple experience.
+The same principle applies in even greater degree to the young of man.
+
+We have seen in a former chapter that what in the ordinary course of
+nature was "predestined" to become one individual nevertheless contained
+the possibility of becoming four or more if the environing conditions were
+made such as to bring about a separation of the cleavage blastomeres. Or a
+fish egg that contained the possibility of becoming a normal two-eyed form
+also contained the possibility of becoming a one-eyed form and could be
+made to do so by certain unusual modifications of the conditions under
+which it develops. However we must not be led so far by the plausibility
+of this comparison that we are misled, for the fact is that we are not
+creating anything new by these environmental upheavals, but are mainly
+altering features that already exist. Beyond doubt the nature of the
+material is of greater import in the specificity of the outcome than are
+the external forces brought to play on it. The only point I wish to make
+is that even what seem ordinarily to be predestined ends can be altered
+by environment, and that the probabilities are that certain features are
+relatively indifferent at their inception, the environmental factor adding
+the final touch of specificity. And our common experience in education
+would indicate that the same is true of mental conditions, including
+behavior. The actual appearance of a particular trait is not necessarily
+always a matter of an initial trend, but may be due merely to the fact
+that its development is possible under certain conditions of environment
+and that these conditions have prevailed in the given instance. And even
+where there is a specific bent it may be arrested through the awakening of
+a contrary impulse, or, on the other hand, its exercise may prevent the
+engendering of the opposite impulse.
+
+=Our Duty to Afford the Opportunity and Provide the Proper Stimuli for the
+Development of Good Traits.--=It is clearly our duty to see that the
+expression of good traits is made possible. We must throw a sheltering
+screen of social environment around the young individual which will fend
+off wrong forms of incitement and chances for harmful expression, and we
+must provide proper stimuli and afford opportunity for development of
+proper modes of expression. We must not forget that a normal instinct
+denied a legitimate outlet will not infrequently find an illegitimate one.
+Above all we must not forget the vital importance of establishing correct
+habits nor the possibility of even replacing undesirable ones by good
+ones. If training can redirect the machine-like behavior of as lowly a
+creature as the starfish into new courses, why should we be so willing as
+some of our genetists would seem to be to throw up our hands and admit
+failure in the case of man before we have even made a rational attempt to
+correct the evils in question? Even in lowly organisms we have seen that
+behavior is not only the result of an innate constitution but also of the
+degree and kind of stimulations to which it has been subjected.
+
+If the individual himself has not the initiative or will to make the
+attempt to set up proper or corrective habits, or to cultivate the
+necessary specific inhibitors, then all the more is it our duty to see
+that he is led by suggestion and drill into the proper routine of
+activities for their establishment. For if the individual with
+propensities toward moral obliquity is to be saved to society it must be
+through the stereotyping effects of good habits.
+
+=Moral Responsibility.--=Beyond question different men have different
+degrees of capacity for mental and moral training. All can not be held
+equally responsible ethically, but the lowermost limit of obligatory
+response to social and ethical demands necessary to rank one as within the
+pale of normal conduct is at such a level that any one not an actual
+defective can in a reasonably wholesome environment surmount it. All
+normal men are responsible for their conduct.
+
+
+
+
+CHAPTER VIII
+
+MENTAL AND NERVOUS DEFECTS
+
+
+Some of the most important and serious problems which confront humanity
+to-day lie in the realm of mental and neural maladjustments. For human
+progress and social welfare are in last analysis based fundamentally on
+the results of normal reactions of human nervous systems. Any serious
+derangement of the latter may, and in certain cases must, lead to more or
+less disaster for the individual and disorder for society of which he is a
+unit. So appalling has the number of neuropathic subjects become in modern
+times that the matter may well cause even the most thoughtless citizen to
+pause and consider.
+
+=Prevalence of Insanity.--=As to the prevalence of insanity, one learns
+from recent charts prepared by a member of the National Committee for
+Mental Hygiene that in 1910 we had more insane (187,454) in our
+institutions than there were students (184,712) in all our colleges and
+universities in the United States, or officers and enlisted men (142,695)
+in our combined United States army, navy and marine corps; further, the
+yearly cost ($32,804,450) of caring for these insane is greater than the
+annual cost of construction ($32,520,100) on such a stupendous undertaking
+as the Panama Canal. In New York over twenty per cent. of the revenues of
+the state go to support the insane. Doctor Lewellys F. Barker, President
+of the National Committee for Mental Hygiene, says: "It is calculated that
+some 250,000 people in the United States are insane. One of every five men
+discharged from the United States army for disability is discharged
+because of insanity, 60 per cent. of the cases being _dementia precox_."
+
+Even in individual states with exceptionally large university populations
+we still find these outnumbered by those of the insane. Thus in Wisconsin
+by 1914 the state university had attained a population of about 4,700
+students resident at the university during the regular school year, and of
+approximately 6,000 attending during some part of the year, but the number
+of insane under restraint in public institutions in the state June 20,
+1912, was 6,851, with an additional 1,284 on parole. This does not include
+the insane in various private sanatoria, and moreover a considerable
+greater number of patients had been treated in these public institutions
+than were resident there June twentieth.
+
+To make such comparisons complete one should, of course, know the average
+length of residence of students in college, and of insane patients in
+institutions. No accurate data on this point are at hand. The average
+period of residence in hospitals for the acutely insane is doubtless
+considerably shorter than the average period of attendance of students in
+college, while on the other hand the average period of residence of
+inmates in asylums for chronic insane is probably considerably longer. For
+example, the Wisconsin State Hospital for the Insane reports a total of
+1,224 patients under treatment, but an average population at any one time
+of only 622 during the year 1911, and the Northern Hospital for the
+Insane, a total of 1,194, with a daily average of 613 during the same
+period. The combined thirty-four county asylums in Wisconsin, for chronic
+insane, had a total population of 5,384 during the year 1911, with a loss
+of 517, or approximately 10 per cent. During 1912 the figures for these
+same institutions run 5,758 and 742 respectively, or a loss of over 12.5
+per cent. The conditions in other states are probably much the same.
+
+In other representative states we find the number of insane in public
+institutions as follows: California, 7,909; Michigan, 7,703; Minnesota,
+5,329; Pennsylvania, 16,992. Epileptics are estimated by alienists to be
+about equal in number to the insane, feeble-minded to be more numerous.
+The estimate that in the United States there are 300,000 feeble-minded is
+probably a minimal figure.
+
+=Imperfect Adjustments of the Brain Mechanism Often Inheritable.--=The
+outside layer or "cortex" of the brain is the region in which the more
+complicated adjustments occur, especially such as pertain to human
+behavior, and inasmuch as this portion of the brain is extremely complex
+and delicate in its mechanism, it is peculiarly liable to derangements
+which, even when slight, may have far-reaching effects.
+
+This brain-mechanism is as much a product of ancestry as is any other
+structure of the body, and it is obvious therefore that imperfect
+adjustments of its structure must be as subject to the laws of
+inheritance as are other malformations of the body. And just as with
+other defects, mental disorders may thus flow from pre-existing ancestral
+maladjustment of the nervous system or from immediate causes thrust upon
+it, such as syphilis, alcoholism, degeneration of the blood vessels and
+traumata. Or, in other words, the mechanism of mentality may be faulty
+from the beginning, or it may be made faulty by bad environmental
+conditions.
+
+The records of the inheritance of insanity, imbecility, feeble-mindedness
+and other forms of nervous and mental defects are truly startling. Active
+researches in this field have been in progress now for several years, and
+as each new set of investigations comes in the tale is always the same. It
+is questionable if there is a single genuine case on record where a normal
+child has been born from a union of two imbeciles. Yet the universal
+tendency is for defective to mate with defective. Davenport gives a list
+of examples, beginning with such a one as this: "A feeble-minded man of
+thirty-eight has a delicate wife who in twenty years has borne him
+nineteen defective children." Little wonder, in the light of such facts as
+these, that the number of degenerates is rapidly increasing in what are
+called civilized countries.
+
+=Many Mental Defectives Married.--=But, it may be urged, these are
+exceptional cases, there is surely no considerable number of mental
+defectives who are married. Let us look at the available facts. In Great
+Britain in 1901, of 60,000 known feeble-minded, imbeciles and idiots,
+19,000 were married, and in the same year, of 117,000 lunatics, 47,000
+were married; that is, a sum-total of 66,000 mentally defective
+individuals were legally multiplying, or had had the opportunity to
+multiply their kind, to say nothing of the unmarried who were known to
+have produced children.
+
+In the state of Wisconsin I note from the tenth biennial report of the
+Board of Control that of 574 patients admitted to the Northern Hospital
+for the Insane during the year from July 1, 1908, to June 30, 1909, 274
+were married and 29 others were known to have been married; this is a
+total of 303 out of 574, considerably over half. At the Wisconsin State
+Hospital for the Insane we find the conditions are no better, for out of
+499 admitted in the year 1909-10, 208 were married and 65 others had at
+some time been married, or a total of 273 out of 499. There is every
+reason to believe that conditions are approximately similar in other
+states.
+
+=Disproportionate Increase in the Number of Mental Defectives.--=Writing
+of conditions in England the Commissioners in Lunacy state in their
+fifty-fourth report that now (1901) there is one officially known lunatic
+to 301.32 individuals of population, whereas in 1859 there was only one to
+536 individuals of population. In Great Britain, taking into account
+mental defectives of all kinds, the 1901 census showed a total of 485,507,
+or 1:85 of total population. Rentoul estimates that 1:50 would be nearer
+the truth because of the fact that the number of officially known mental
+defectives is much less than the actual number. The conditions in Ireland
+are even more impressive, for in 1851 there was one known lunatic to 657
+individuals of population; in 1871, one to 328, and in 1901 one to 178.
+When all allowance is made in these statistics for the greater accuracy of
+recent enumeration, and for other modifying influences, such as migration,
+we are still forced to believe that an alarming increase in insanity is in
+progress and that society is woefully derelict in permitting the marriage
+of such unfortunates.
+
+A census of the insane under public care in Wisconsin June 30, 1910, not
+counting the paroled, shows 6,537, or one to each 357 of population, since
+the population of the state was then 2,333,860. If, however, we should add
+the number of insane in private sanatoria and the number unconfined the
+proportion of normal individuals would be very much reduced.
+
+In the United States as a whole, while I know of no data giving the number
+of married insane, it is estimated that at least one-fourth of the insane
+are not in asylums or hospitals. In all states the number of insane in
+state institutions (there are no available records of most private
+institutions) is rapidly increasing. According to the special census of
+1903 covering a period of fourteen years, during which the general
+population increased thirty per cent., the number of insane in
+institutions increased one hundred per cent. This is due doubtless in part
+to the fact that because of better facilities for keeping them a
+proportionately greater number of insane are being sent to state hospitals
+than in former years. Moreover, improved sanitation has cut down the
+death-rate in asylums. The increase is in such vastly greater proportion
+than the increase in general population, however, that it seems impossible
+to attribute it wholly to the greater accuracy of recent enumerations and
+the increasing custom of confining the insane in asylums. This is a matter
+that demands our gravest attention and one that should be investigated
+with the greatest thoroughness. One of the most disquieting facts in the
+situation in most states is that many patients--an average of
+approximately one thousand a year, in Wisconsin for example--are on parole
+subject to recall. This means that although it is recognized that these
+patients are likely to have to be returned to the asylum or hospital,
+little or no restraint in the meantime is placed on their marital
+relations.[8]
+
+=Protests Voiced by Alienists.--=Is it any wonder under the circumstances
+that we find Doctor Charles Gorst, superintendent at the Mendota Hospital,
+voicing in his 1910 report the following vigorous protest--and certainly
+such men as he are in the best position to know. He says: "No one doubts
+for a moment that defective mental conditions are transmitted from parent
+to child as surely as the physical defects and deformities. Every one
+knows that it is common for defectives to be attracted to each other and
+marry, and that the defects of both parents are liable to be transmitted
+to the children. It is also true that there are more children born in such
+families; and for that reason the percentage of defectives is continually
+on the increase. The report of the state of Illinois shows the increase to
+be alarming, and many other states are no better. It is absolutely wicked
+that the persons suffering from periodical insanity should be allowed to
+return to their homes to propagate and scatter their children about the
+state as dependents."
+
+=Examples of Hereditary Feeble-Mindedness.--=No one can look at the
+remarkable series of charts and records brought together by Doctor Goddard
+of the institution at Vineland, New Jersey, and by other directors of
+similar institutions, and doubt for an instant the inheritability of
+feeble-mindedness and allied defects. In some instances the family history
+has been followed back as far as five generations, and it is always the
+same dire sequence of insanity, idiocy, epilepsy or feeble-mindedness,
+from generation to generation. For example, Fig. 33, p. 236, is one of
+Doctor Goddard's charts. It shows thirteen descendants of a supposedly
+normal father (possibly a carrier) and a feeble-minded mother, of whom
+seven were feeble-minded, the others dying in infancy. The mother herself
+was one of seven feeble-minded children, who were in turn the descendants
+of feeble-minded parents, of whom the woman had five feeble-minded
+brothers and sisters. In Fig. 34, p. 237, he shows mental defects running
+through four generations. Fig. 35, p. 238, is a remarkable exhibit which,
+starting in the fifth generation back with a feeble-minded, alcoholic
+man--the mental condition of his wife being unknown--shows that in every
+generation down to and including the present there has been nothing but
+feeble-minded (or worse) offspring, leaving out of account two unknown
+and a number who died in infancy without revealing their mental condition.
+This is true notwithstanding the fact that in the course of the various
+generations there had been several matings with apparently normal
+individuals. The new blood, however, instead of redeeming the tainted
+stock, itself became vitiated. The numerous specific cases of inheritance
+of family traits reviewed in recent books or in special reports of trained
+workers give us abundant confirmatory evidence of the inevitable
+inheritance of various nervous and mental defects.
+
+
+[Illustration: FIG. 33
+
+Inheritance of feeble-mindedness (after Goddard): squares represent males,
+circles females; F, feeble-minded; N, normal; E, epileptic; I, insane; C,
+criminal; T, tuberculous; d. inf., died in infancy; the hand shows the
+individual from whom the record was traced back; small black circle
+indicates miscarriage.]
+
+
+=Difficult to Secure Accurate Data.--=It is obvious, of course, that in
+tabulations such as these there may lurk considerable margins of error.
+Notwithstanding our Binet-Simon and other tests for feeble-mindedness, for
+example, there is yet much to be desired in the way of accuracy. Many
+cases just bordering normality are by no means easy to decide. Then again
+in most human records, when one gets back beyond the third or, at most,
+the fourth generation, the investigator has to depend on the hearsay
+evidence of relatives, friends or neighbors, and how vague this generally
+is can only be appreciated by those who have themselves tried to collect
+such data. But in spite of all the difficulties, there is little doubt
+that the more carefully prepared records are sufficiently accurate to
+establish the fact beyond dispute that defective tends in large measure to
+breed defective.
+
+
+[Illustration: FIG. 34
+
+Inheritance of feeble-mindedness (after Goddard); symbols same as in Fig.
+33, p. 236.]
+
+
+One serious drawback in making a study of the inheritability of insanity
+and other nervous disorders is that so far we have dealt mainly with mass
+effects rather than specific neuroses. But even when the latter is
+attempted we are confronted by the fact that there are various
+intergradations of the recognized types of defect, that because of
+varying degrees of defect in the same type a standard is hard to
+establish, and above all that what appears as a specific mental malady in
+one individual may crop out in his descendants in an entirely different
+guise. Moreover, not only the predisposition of the individual, but age
+and precipitative cause enter as factors in determining the ultimate
+symptoms.
+
+
+[Illustration: FIG. 35
+
+Inheritance of feeble-mindedness (after Goddard); symbols same as in Fig.
+33, p. 236.]
+
+
+=Feeble-Mindedness and Insanity Not the Same.--=Authorities make a sharp
+distinction between insanities on the one hand and feeble-mindedness on
+the other. According to Goddard, not only is there no close relationship
+between the two conditions, but in reality they stand at opposite ends of
+the psychical scale. In general, insanity is a degenerative process,
+whereas feeble-mindedness is an arrest of development. In the first case
+the victim loses part of the mentality he once had, in the second he stops
+short of normal development.
+
+=Many Types of Insanity.--=The commonest manifestations of insanity are
+undue depression, apathy, excitement, instability, obsessions,
+hallucinations and delusions. Some mental disorders are associated with
+recognizable structural changes in the nervous system, but the structural
+basis of many is not known.
+
+In general there is more doubt about the inheritability of some of the
+insanities than about cases of mental deficiency. The term insanity is
+merely a loose descriptive one, and we shall gain little definite
+knowledge about the inheritance of such maladies until we study each
+separate insane diathesis specifically. Psychiatrists recognize many
+different forms of insanity, some of them very distinct from others and
+the product of unrelated underlying causes. Often it is only a question of
+degree or sometimes a matter of chance as to whether a given individual is
+certified as insane or not. A neuropathic person who manifests certain
+anti-social activities is sure to be classed as insane, whereas another
+individual with the same diathesis in a less degree might pass
+unrecognized. It is almost impossible in some instances to tell just where
+the border-line between a neuropathic and a normal constitution lies. Many
+of the idiosyncrasies of the insane, indeed, are merely exaggerations of
+characteristics seen in normal people. Recent studies of the psychology of
+the insane show that most of their hallucinations and delusions are
+closely related to some previous mental experience they had before
+becoming insane. And it has been found that the surest means toward
+removing the obsessions of the patient in curable cases is to ferret out
+these earlier experiences and correct the wrong impressions regarding
+them. Again, certain forms of insanity do not become manifest except as
+special reactions to particular environmental conditions, and if these
+conditions do not happen to occur, then the neuropathic constitution
+though existing would not be revealed. Certain critical periods of life
+such as puberty, pregnancy and the close of sexual life are particularly
+likely to test out the mentally unstable, although such individuals may
+have maintained normal mental balance up to the crisis in question.
+
+=Not All Insanities of the Same Eugenical Significance.--=Of the various
+kinds of insanity some seem to be of much greater eugenical significance
+than others, not only because they are strongly heritable, but also
+because of the periodicity of the attacks. The patient may be repeatedly
+in and out of the asylum and in his sane intervals wholly unrestrained as
+far as propagating his kind is concerned. _Manic depressive_ psychoses and
+_dementia precox_ in the order named represented the largest number of
+admissions to the Wisconsin State Hospital for the Insane in 1911 and
+1912, and both of these very frequently have a hereditary basis. Fig. 36,
+a chart showing the insanity in a local family as worked out by one of my
+pupils, is a good example of a recurrent type. The father (Fig. 36, p.
+241) was about eighty-two years old when the record was made. His memory
+was poor and he could not talk connectedly, although this was possibly
+attributable to old age rather than to insanity. His brother, written to
+in Ireland, stated that to his knowledge there had never been insanity in
+his side of the family. The mother (2) was insane at nine, again at
+twenty-nine and again at thirty-six. In her later life she has been in the
+Mendota Hospital for the Insane five times and in the County Asylum twice.
+The eldest daughter (3) has been in the State Asylum five times and is now
+at home. The next daughter (4) spent five months in the asylum in 1885.
+Another daughter (5) likewise spent a short period in the asylum. Two sons
+(6, 7) have each spent two periods in the asylum, and a third son (8) has
+had an attack of insanity. The youngest child died at the age of three.
+Thus of the eight adult children six have been insane at some time. The
+cases in this family seem all to be instances of manic-depressive
+insanity.
+
+
+[Illustration: FIG. 36
+
+Inheritance of insanity in the L---- family. See text for description.]
+
+
+=A Neuropathic Constitution May Express Itself Differently Under Different
+Conditions.--=Some of the difficulties of getting genealogies of specific
+forms of insanity are obvious from the following quotations chosen from
+the works of eminent psychiatrists. Kraepelin, for instance, expresses the
+opinion that: "The psychopathic charge of a family may reveal itself not
+only by the appearance of mental disorders but also by other forms of
+manifestation. Here belong before all, those diverse slighter deviations
+from mental health which go to make up the borderland of insanity:
+nervousness, states of anxiety and compulsion, constitutional depressions,
+slight hysterical disorders and forms of feeble-mindedness, tics; also odd
+characters, peculiarities in mode of living, criminal tendencies, lack of
+self-control, intemperance, love of adventure, mendacity, suicide on an
+inner basis."
+
+From the volume of Church and Peterson on _Nervous and Mental Diseases_ a
+further confirmatory opinion may be cited: "In determining the factor of
+heredity we must not be content with ascertaining the existence of
+psychoses in the ascendants, but must seek, by careful interrogation of
+various members of the family, for some of the hereditary equivalents,
+such as epilepsy, chorea, hysteria, neurasthenia, somnambulism, migraine,
+organic diseases of the central nervous system, criminal tendencies,
+eccentricities of character, drunkenness, etc., for these equivalents are
+interchangeable from one generation to another, and are simply evidence of
+instability of the nervous system. It is the unstable nervous organization
+that is inherited, not a particular neurosis or psychosis, and it must be
+our aim in the investigation of the progenitors to discover the evidence
+of this."
+
+=Certain Forms of Insanity, But Not All, Seem to Behave as Mendelian
+Recessives.--=A number of psychiatrists and investigators of the
+inheritance of insanities (Rudin, Lunborg, Davenport, Rosanoff, Jolly),
+although working independently and in different countries, concur in the
+opinion that manic-depressive insanity, dementia precox and allied
+psychopathic conditions tend to occur after the manner of a Mendelian
+recessive. On the other hand such maladies as Huntington's chorea are
+transmitted as a dominant and in all probability at least half of the
+children of an afflicted individual will inherit and manifest the defect.
+As to inheritance of various other psychoses we have too few accurately
+charted pedigrees for most types to make very positive statements about
+their degree or manner of inheritance. Little can be said beyond the
+statement that there is a decided tendency for various forms to recur in
+offspring. Where more than one case of insanity occurs in a given family
+or stock it is strong presumptive evidence that a hereditary defect is at
+the bottom of it. As Doctor Wilmarth says, "Mental accident may occur in
+any family, but it is rarely a second case occurs unless there is a
+tendency to nerve degeneracy." For example, of 818 insane at the Wisconsin
+State Hospital for the Insane during the biennium 1909-10, 187, or
+practically one-fourth were positively known to have insane relatives. Of
+these, 24 had insane fathers, 31 insane mothers, 30 insane brothers, 23
+insane sisters, 25 insane uncles, 21 insane aunts, and 21 insane cousins.
+Where definite information could be obtained it was found that of the
+5,700 admissions of insane patients to the New York state hospitals
+during the year ending September 30, 1911, 27.7 per cent. of the cases
+showed a history of insanity in the family and an additional 22.9 per
+cent. showed a history of alcoholism, nervous diseases and the like.
+
+=Grades of Feeble-Mindedness.--=As to the various grades of
+feeble-mindedness, while no sharp lines of demarcation can be drawn, a
+rough and ready test usually applied is the relative ability of such
+subnormal individuals to take care of themselves. In all, the conditions
+exist from birth or shortly after. _Idiots_ are such defective individuals
+as are unable to take care of themselves even to the matter of guarding
+against common physical dangers. Their mentality does not progress beyond
+that of a two-year-old child. _Imbeciles_ can take care of themselves in
+the cruder physical ways, but are unable to earn their living. Their
+mental age ranges from three to seven years inclusive. _Morons_, or the
+"feeble-minded" in a more specific usage of the term, can under proper
+direction become more or less self-supporting but they are as a rule
+incapable of undertaking affairs which demand judgment or involve
+unrestricted competition with normal individuals. Their intelligence
+ranges with that of normal children from seven to twelve years of age. The
+last class grades up insensibly into the shiftless, ne'er-do-well types
+which exist in every community. It is the hordes of the feeble-minded in
+the restricted sense that afford our most serious problems to-day. The
+idiot and the imbecile are usually early and easily recognized and are
+kept more or less under restraint, but the higher grades of feeble-minded,
+the so-called moron type, can be detected often only by carefully devised
+tests.
+
+=About Two-Thirds of the Feeble-Minded Have Inherited Their
+Condition.--=Concerning the various types of feeble-mindedness there is
+strong evidence that heredity is a factor of greater magnitude than in
+most insanities. All facts point to the conclusion that most mental
+deficiency is strongly inheritable and that the majority of our defectives
+of this type come from degenerate stocks. Practically all specialists at
+the heads of asylums and homes for the mentally deficient concur in the
+opinion that about two-thirds of the cases are hereditary. For example,
+Doctor Alfred Wilmarth, superintendent of the Wisconsin Home for
+Feeble-minded, says: "My own observations, and those of others in this
+country and Europe, would indicate that at least two-thirds of the
+feeble-minded have defective relatives."
+
+In his study of two thousand children tested by the Binet measuring scale
+for intelligence, Doctor Henry H. Goddard, director of the Department of
+Research at the Training School for Feeble-minded at Vineland, N. J.,
+remarks concerning heredity of feeble-mindedness: "But we now know that
+sixty-five per cent. of these children have inherited the condition, and
+that if they grow up and marry they will transmit the same condition to
+their offspring. Indeed, we know that this class of people is increasing
+at an enormous rate in every community and unless we do something to stop
+this great stream of bad protoplasm we shall some day be swamped in a sea
+of degeneracy."
+
+E. R. Johnstone, superintendent of the training school at Vineland, N.
+J., in a recent bulletin remarks concerning feeble-minded and epileptics,
+"We are now convinced that from sixty to eighty per cent. of the cases are
+hereditary."
+
+Again, we find Doctor A. C. Rogers, superintendent of a school for
+feeble-minded in Minnesota, saying, "We have no survey of mentality in
+this country except in very small areas, but probably about sixty-five per
+cent. of the feeble-minded children that we know of are feeble-minded from
+heredity; that is, they come from families in which there is much
+feeble-mindedness, usually associated with various neuroses or psychosis.
+There are about thirty-five per cent. approximately that are acquired
+cases. These cases develop from various things. Full development may be
+prevented during gestation, or early childhood, or early adolescence, but
+these acquired cases are entirely distinct from the hereditary ones."
+
+In a recent paper Doctor Martin W. Barr, chief physician for the
+Pennsylvania Training School for Feeble-minded Children, says: "In my
+individual study of 4,050 cases of imbecility, I find 2,651, or 65.34 per
+cent., caused by malign heredities; and of these 1,030, or 25.43 per
+cent., are due to direct inheritance of idiocy; and 280, or 6.91 per
+cent., to insanity." From these figures it will be seen that Doctors Barr,
+Goddard, Wilmarth, Johnstone and Rogers all agree in their estimates;
+namely, that two-thirds of our imbeciles are so through inheritance.
+
+=Some Results of Non-Restraint of the Feeble-minded.--=The following
+excerpt from a paper by Doctor Barr, is a fair sample of what happens
+when such defective individuals are not restrained from propagating their
+kind:
+
+    "My own study and observation alone, of over 4,000 degenerates, shows
+    such examples as: A man 38 years of age, the father of 19 defective
+    children, all living, he and his wife both under par mentally; as was
+    another couple, with 9 imbecile children; an idiot woman with 7 idiot
+    children. A forcible instance is that of a man with two daughters and
+    one illegitimate grandchild, all feeble-minded.... I could name a
+    family, one of the proudest in the land, where there are five
+    children, an aunt and two uncles, all feeble-minded.
+
+    "Yet another, which in seven generations numbering some 138
+    individuals, records 10 still-born children (premature births), 16
+    insane, 7 imbeciles, 3 epileptics and 32 with mental peculiarities so
+    pronounced as to occasion remark. Of the 138 there remain 80
+    apparently normal, who are nevertheless hopeless slaves of a neurotic
+    heredity, direct or collateral.
+
+    "In a study of 15 imbecile girls, 3 were recognized prostitutes, 9 had
+    each 1 illegitimate child (2 being the result of incestuous
+    intercourse with brothers); 1 had 2; 2 epileptics had, the one 3, and
+    the other 4 idiot children.
+
+    "Four feeble-minded women had 40 illegitimate children.
+
+    "A feeble-minded woman living in an almshouse since early childhood,
+    allowed to go out to service periodically, had given birth to six
+    illegitimate children, all inheriting her defect.
+
+    "An imbecile drunkard is the father of three feeble-minded children.
+    The daughter, seduced before the age of sixteen, gave birth to an
+    idiot child; one son is a harmless imbecile, but the other is a moral
+    imbecile, a sexual pervert, a thief on the streets, and a pyromaniac,
+    firing in sheer wantonness a large mill property.
+
+    "Another shows the entire family for three generations below normal.
+    Father, mother, mother's sister, and father's uncle, all imbecile.
+    Five children feeble-minded. One girl had a proposal of marriage, and
+    one boy is married to a feeble-minded girl.
+
+    "One insane woman, whose brother and sister committed suicide, had
+    five sons. The oldest, feeble-minded, a drunkard and hobo, had one
+    son, a criminal. The second son, insane, had three imbecile children.
+    The third, an insane epileptic, had three imbecile sons, one of whom
+    was an epileptic. The fourth son was insane. The fifth, apparently
+    normal, had a morally imbecile son and an epileptic daughter."
+
+Yet striking as is the inheritance of these maladies, Doctor Barr points
+out that of the 10,000 known cases of feeble-mindedness in Pennsylvania,
+only 3,500 are sequestrated. This leaves a balance in that state of 6,500
+totally irresponsible individuals to work havoc in society by producing
+their kind.
+
+=Inheritance Not a Factor in Some Cases of Mental Deficiency.--=On the
+other hand as our data show, there remain about one-third of the mentally
+deficient type to be accounted for on other than a basis of heredity. As
+already noted, some of these are doubtless the product of suppressions of
+normal development by various extraneous factors operating before or
+shortly after birth. There is one class particularly, estimated by some
+authorities as constituting as high as thirty per cent. of the
+feeble-minded which is unusually puzzling. These are the so-called
+mongolians. The name is given because the features of such individuals
+bear more or less resemblance to those of some of the Mongolian races. The
+defect does not seem to be hereditary although it is usually congenital.
+It appears to be due to something which interferes with prenatal
+development. Whatever the conditions, whether lack of nutrition in the
+mother, alcoholic or other poisoning, the cases seem to be as hopelessly
+incurable as are the hereditary forms. From the social standpoint, of
+course, such individuals are in their immediate generation, as incompetent
+or as dangerous to society as those suffering from the more surely known
+hereditary forms of mental defect.
+
+=Epileptics.--=Although epileptics are not classed as imbeciles
+ordinarily, as a matter of fact no sharp distinction can be drawn between
+the two classes. Doctor Wilmarth says, "Epilepsy and mental deficiency are
+as closely related as branches on the same tree.... Over one-half and
+perhaps two-thirds of all feeble-minded are subject to convulsive seizures
+at some period of their lives, and we are never surprised at the
+appearance of epilepsy in any feeble-minded person. On the other hand, so
+small a percentage of epileptics maintain normal mental actions as hardly
+to be worth consideration ... even those who retain a normal mind in the
+early stages of the diseases almost infallibly become imperfect later."
+How slight a chance the epileptic has of ever becoming normal may be
+inferred from a statement made by Doctor Frank Billings in a paper read
+before the Illinois State Medical Society in 1909 to the effect that "ten
+per cent. or more can be cured by proper care."
+
+According to the estimates of "The Committee of Fifty" in the state of
+Illinois, who have been agitating for the establishment of a colony for
+epileptics, there are 10,000 of these unfortunates in that state. The
+consensus of opinion of experienced workers in various states is that
+there is about one epileptic to each three hundred fifty to five hundred
+inhabitants.
+
+=In Heredity Conditions of Feeble-Mindedness Are Probably Recessive to
+Normal Condition.--=As to the mode of inheritance of the various forms of
+feeble-mindedness, the evidence points to such defects in the main as
+being recessive. However, no particular grade can be picked out and shown
+to be a pure recessive. For instance, the children of two epileptics will
+be defective but it is impossible to predict always whether the defect
+will appear as epilepsy or feeble-mindedness. This is doubtless due to the
+fact that mental deficiencies even of the inheritable type are not all due
+to the same specific cause, and in many cases the individual is defective
+in more than one direction. If one or more of a great number of units
+which are necessary for complete mental development are lacking, obviously
+mental deficiency will result. In other words, feeble-mindedness and
+allied disorders may not be definite characters, but simply evidences of
+the fact that the nervous system has not developed all factors necessary
+for normal mental coordination. Goddard, however, one of our best
+authorities on the heredity of feeble-mindedness, is inclined to regard
+the condition as a unit character, "due either to the presence of
+something which acts as an inhibitor, or due to the absence of some
+stimulus which sends the normal brain on to further development."
+
+Supposing nervous defects finding expression in feeble-mindedness,
+epilepsy and related conditions, to act as a Mendelian recessive, then the
+marriage of one such defective with another should yield only mentally
+enfeebled offspring. How nearly this expectation may be realized is seen
+from the following examples.
+
+In an extensive study[9] of feeble-mindedness, just from the press, Doctor
+Henry H. Goddard points out that of 482 children with both parents
+feeble-minded all but six were feeble-minded. Even the exceptions may be
+apparent rather than real as there is possibility of mistake in judging
+the condition of the parents or of the children themselves. Moreover, with
+the feeble-minded one is not always sure of the paternity of a child, as
+is instanced by Doctor Goddard in a case quoted from Doctor Emerick in
+which of twelve children in a white family with both father and mother
+feeble-minded ten were feeble-minded and two were not, but these two were
+_mulatto_ children.
+
+In a paper by Weeks (_The Inheritance of Epilepsy_), in part an extension
+of an earlier joint paper by Davenport and Weeks, is recorded among others
+a study of twenty-seven fraternities in which both parents were either
+epileptic or feeble-minded. Of the 28 progeny, 19 lived long enough to
+reveal their mental state. Of these 3 were feeble-minded, 8 epileptic and
+8, from parents who developed epilepsy late in life, were what Doctor
+Weeks terms "tainted." In 15 fraternities in which one parent was
+epileptic and the other feeble-minded he found there had been 81
+conceptions. Of these 7 were too young to classify and 19 had died before
+fourteen years of age. Of the remaining 55, 28 were epileptic, 26
+feeble-minded, and 1 insane. Again, in 9 families in which the parents
+were both feeble-minded, of the 38 surviving offspring who were old enough
+to classify, 7 were epileptic, 29 feeble-minded, and 2 drunkards. In 5
+families where one parent was insane and the other epileptic or
+feeble-minded, 5 children died before the age of fourteen, the condition
+of 2 was unknown, 2 were epileptic, 4 feeble-minded, 1 insane, 8 tainted,
+and 7 seemingly normal. Regarding the latter Doctor Weeks says they came
+from two families where in one case the father's insanity seemed to be
+traumatic and in the other alcoholic.
+
+In a few cases where the defect in one parent has apparently been of a
+type different from the defect of the other parent a "normal" child was
+produced. That is, presumably each parent carried normality in the trait
+defective in the other so that the child became simplex with reference to
+each defect. Davenport points out that not infrequently two deaf-mutes
+whose defects are due to different causes may have normal children.
+
+In general, however, the reasonable expectation is that where two
+feeble-minded individuals marry, a very common occurrence, the children
+will all show mental deficiency. A mating between a feeble-minded person
+and one of perfectly normal stock will apparently result in normal
+children although they will be carriers. There is some evidence, however,
+that such carriers may occasionally show "taints" of abnormality in the
+form of migraine (nervous sick headache), alcoholism, queerness, violent
+temper, etc. Thus according to the studies of Doctor Weeks, "In 50 matings
+where at least one parent is migrainous, there were 350 conceptions, of
+which number enough is known of 212 to classify 55, or 26 per cent., as
+epileptic; 12, or 6 per cent., as feeble-minded, with the others tainted
+or normal. In the 131 matings where at least one parent is alcoholic,
+there were 845 conceptions. Of the 494 classified, 151, or 31 per cent.,
+were epileptic; 54, or 11 per cent., feeble-minded, with the balance
+tainted or normal." Marriage between two carriers will cause the defect to
+reappear in active form in approximately 25 per cent. of the offspring and
+50 per cent. will continue to be carriers.
+
+=Many Apparently Normal People Really Carriers of Neuropathic
+Defects.--=There is considerable evidence that many apparently normal
+individuals of our average population are in reality carriers of some form
+of neuropathic defect, some authorities placing the proportion
+provisionally at over thirty per cent. This being true, then it is easy to
+explain the apparently unaccountable appearance of epilepsy,
+feeble-mindedness, or similar defects among the children of what pass for
+normal stocks. The probabilities are that in many cases it means simply
+that the parents of the defective children have been carriers.
+
+As to the contention that in preventing the propagation of the
+feeble-minded we may be depriving the world of geniuses, Doctor Goddard
+remarks: "It is a significant fact that in our three hundred family
+histories totaling 11,389 individuals not a single genius has been found.
+Not only are there no geniuses but the fact can not be too strongly
+emphasized that even the people who are considered normal ... are not as a
+rule people of average intelligence...." However, between insanity and
+genius he finds more kindred spirit.
+
+=Tests for Mental Deficiency.--=As to tests for mental deficiency, the one
+commonly meted out to victims in the every-day world is the
+social-economic one of survival in the competitions of life. The mentally
+deficient fail. Although often unrecognized as feeble-minded they drift
+through life social and economical derelicts who have to be supported by
+the community.
+
+Of laboratory tests many have been devised. While all yet leave much to be
+desired, still through their application the majority of mental defectives
+can be detected. Fairly accurate standards of normality have been
+established from which the relative degree of "backwardness" can be
+determined. We have just awakened to the importance of detecting
+defectives early in life, hence many of our tests have been planned with
+reference to children. They are based not so much on training or conscious
+learning as on fundamental processes which develop at certain ages in
+children. Another impetus toward securing adequate criteria of mental
+deficiency has been the crying need of having some easily applied standard
+for detecting the very large numbers of defective immigrants who are
+continually seeking to enter the United States.
+
+Most of the methods consist of "performance" tests which are planned to
+test the powers of perception, concentration, application, ingenuity and
+education of the subject. Previous environment, education and the
+difficulties under which the subject may be laboring at the time of the
+test must, of course, be taken into account. It is particularly difficult
+to get adequate tests for the immigrant which will enable one to
+distinguish between ignorance, stupidity, fear and temporary psychic
+depression on the one hand, and congenital mental deficiency on the other.
+
+Perhaps the most successful single set of tests for mental deficiency is
+that known as the Binet-Simon Scale. From an examination of large numbers
+of French school children Binet constructed a scale of tests of increasing
+complexity accurately graded to age and previous training of the average
+normal child. In the Binet-Simon system tests are given for each age from
+three years to thirteen. When a child successfully passes the tests for
+his age he is classed as normal. If he succeeds only in tests which
+normally are those given for a child a year younger then he is backward to
+the extent of one year. Similarly he may show by these graded tests that
+he is backward to the extent of two years, three years and so on. If a
+child is more than three years backward according to the test he is
+regarded as mentally defective. Various corrections and adjustments of the
+original scale have been worked out to allow for unevenness in mental
+development. On the whole the scheme works out satisfactorily when applied
+by one skilled in its use. The attitude of the examiner, however, is of so
+great importance that the tests are of less value in the hand of
+inexperienced workers. A revision of the scale to adapt it better to
+American children has recently been made by Doctor Goddard.[10] Besides
+the Binet-Simon tests various performance tests, standardized for children
+of different ages, such as Seguin's form board, Healy's pictorial
+completion test, Fernald's construction puzzle, the Rossolimo test, De
+Sanctis test, etc., are used by different investigators. Questions
+designed to reveal moral tone are also employed. Doctor Howard A. Knox,
+assistant surgeon United States Public Health Service, in a recent
+article[11] gives an interesting account of the tests applied to determine
+the exact mentality of immigrants entering the United States together with
+a brief review of various tests. A full account and discussion of the
+various tests for the mentally subnormal will be found in a recent
+publication by Doctor William Healy,[12] director of the Juvenile
+Psychopathic Institute, Chicago.
+
+=The Backward Child in School.--=It is only in recent times that we have
+come to realize the seriousness of the problem which the backward child
+presents in our schools. It is of the utmost importance to discover early
+in school life which of the backward children owe their condition to
+adenoids, defective sight or hearing, poor nutrition, imperfect
+circulation, or other remediable defects, and which are the victims of
+innate mental deficiency. The treatment of the individual must be very
+different in the two cases. In the one the condition can be cured by
+proper manipulations or other treatments; in the other it can only be
+ameliorated. All school children who are two or three years below grade
+should be rigidly inspected by the medical examiner.
+
+From a study of about two thousand children comprising the first five
+grades of an entire public school system Goddard found that eighteen per
+cent. were definitely "backward." Of these between two and three per cent.
+were actually feeble-minded, the condition in the remaining fifteen per
+cent. being presumably capable of correction. Other similar surveys have
+given practically the same results.
+
+=The Exceptionally Able Child Likely to Be Neglected.--=However, while we
+must not forget that it is important to recognize backward children and to
+see that they are segregated into small groups which are not required to
+do the full amount of work in regular time, it is equally urgent to see
+that the unusually bright individual is also given opportunity to advance
+more rapidly than the rank and file. Only too often the holding back of a
+child in school leads to lack of interest and habits of mental laziness,
+and sometimes to truancy and incorrigibility. The general attempt in our
+graded schools to keep all children close to the average is to be strongly
+condemned.
+
+=Cost of Caring for Our Mentally Disordered.--=Doctor Charles L. Dana,
+member of the National Committee for Mental Hygiene, estimated in 1904
+that the actual cost of caring for feeble-minded and insane in the
+United States amounted to sixty million dollars, to which should be added
+the corresponding loss in industrial activity on the part of the
+afflicted,--at least twenty million dollars more, and he figures that the
+amount was increasing at the rate of four per cent. per annum. Many
+investigators concur in the opinion that our insane and feeble-minded
+alone cost us far above one hundred million dollars. Adding to this
+economic burden the cost of our delinquents and criminals the total
+expense becomes stupendous. And when we consider still further the even
+greater burden of suffering of the unfortunates themselves and the sorrows
+of those to whom they are dear, a burden not measurable in money, the
+feeling that something must be done to relieve the situation becomes
+overpowering.
+
+=Importance of Rigid Segregation of Feeble-Minded.--=As regards the really
+feeble-minded little can be done beyond making them as happy as possible
+and developing the limited gifts they have been given by nature. Their
+teaching must be in the main concrete and simple. At the age of puberty it
+is imperative to see that the sexes are separated and kept under
+sufficient permanent supervision to prevent all possibility of
+procreation. There is neither economic nor common sense in even allowing
+the remotest chance of such occurrences as the following: "This is the
+case of a feeble-minded and epileptic woman who had six children by
+various persons while an inmate of a county poor house. One child at the
+age of eighteen died in the almshouse, two died in infancy, one was
+epileptic (the son of a man with a criminal record) and two who are now
+living in the almshouse are feeble-minded, one being the son of a negro."
+Again, we find a superintendent of an English almshouse reporting that one
+hundred and two out of one hundred and five children born there in five
+years were feeble-minded.
+
+As conditions are to-day every institution for the feeble-minded has a
+long waiting list and the same is true of most asylums for the insane.
+Instead of providing the prolonged care necessary for such patients,
+institutions are forced to discharge many prematurely in order to make
+room for more urgent cases.
+
+=Importance of Early Diagnosis of Insanity.--=In insanities, even when of
+hereditary origin, there is much hope in certain cases of greatly
+benefiting the individual, though a permanent cure, or at least the
+establishment of procreative fitness may be impossible. It is extremely
+important that the public realize how much can be done through early
+examination and advice in such mental afflictions. Most of the insane who
+recover usually do so within a few months of their first alienation, hence
+the importance of losing no time in detecting the condition and securing
+early treatment. It is now well known that many cases of chronic insanity
+may be measurably improved under the care of a psychiatrist by systematic
+re-education, especially in industrial lines. But how little of this may
+be expected at the hands of the untrained custodians who "feed" the
+inmates of our county almshouses, to which in many states the chronic
+insane are entrusted, is obvious.
+
+=All Insane Should Be Passed Upon by Competent Psychiatrists.--=The
+atrocious system of turning the chronic insane over to county poorhouses
+manned by supervisors whose chief qualification for the position has not
+infrequently been the lowness of their bid for boarding and caring for the
+inmates, can not be too strongly condemned. Incredible as it may seem, in
+some states the court can on its own judgment send patients directly to
+these institutions without first submitting them to the study of expert
+physicians in the state hospital for the insane. The viciousness of such
+procedure is evident when one realizes that often careful scrutiny on the
+part of the very best experts, extending over a considerable period of
+time, is required before the true condition of the patient can be
+determined. Recently a psychiatrist of high standing, who was gathering
+data on county asylums for a national organization, informed the writer
+that beyond the shadow of a doubt he had come across case after case in
+county asylums which would have been curable under proper treatment.
+
+Here again the responsibility in last analysis must rest upon us as
+citizens, for it is largely through our intelligent demands as voters that
+conditions will be improved and competent experts be put in charge of
+county asylums as well as of the state hospitals for the acutely insane.
+
+=Some Insanities Not of Hereditary Origin.--=Some alienists believe that
+self-poisoning known as _auto-intoxication_, due to improper elimination
+of poisons generated through faulty digestion or metabolism, if of long
+standing, may be not only a contributory but a more or less direct cause
+of insanity. About twenty per cent. of insanities of men living in cities
+and about fifteen per cent. of those living in the country seem to be
+directly related to the intemperate use of alcohol. The corresponding
+figures for women are seven per cent. and one per cent. respectively.
+General paresis or softening of the brain is probably invariably preceded
+by syphilis. About twenty-two and five-tenths per cent. of the first
+admissions to hospitals for the insane from city-dwelling men, and eight
+per cent. from men living in the country in the state of New York are
+cases of this kind of insanity. The corresponding figures for women are
+five and five-tenths per cent. and two and five-tenths per cent.
+respectively.
+
+=Importance of Heredity in Insanity Not Appreciated.--=We have already
+seen that heredity plays an important part in insanities. There can be
+little doubt that the tendency is to under-estimate rather than
+over-estimate its importance. Many cases said to be "caused" by mental
+strain such as those occasioned by domestic infelicities, business
+reverses and the like should in all probability be fundamentally
+attributed to something far more deep-seated than the more obvious cause.
+In many such instances there is little doubt that an inherent weakness in
+mental make-up exists which predisposes the individual toward mental
+breakdown. This is more apparent when one recalls that there are thousands
+of other individuals who undergo equally great or greater calamities
+without loss of mental balance. There are well-recognized types of mental
+disposition which later contribute to corresponding forms of insanity. In
+many instances the final catastrophe may be averted if the "peculiar"
+individual can be kept in good health and guided into right habits of
+thought. Undoubtedly certain infectious diseases, arterio sclerosis,
+various poisons in the blood, child-birth, and similar influences often
+enter as important contributory factors. In all cases of cure, however, we
+must face the fact that under existing conditions these mentally restored
+individuals are released into society without let or hindrance as regards
+their marital relations.
+
+
+
+
+CHAPTER IX
+
+CRIME AND DELINQUENCY
+
+
+=The Relative Importance of Heredity and Environment in This Field
+Uncertain.--=The whole question of crime and delinquency is a highly
+complex one. Here, perhaps, more than in any other phase of race
+betterment we find the greatest difficulty in separating the effects of
+hereditary predisposition from the results of unfavorable environment.
+While there is no longer a reasonable doubt about such nervous disorders
+as epilepsy, feeble-mindedness and certain forms of insanity being rooted
+largely in ancestral taints, the degree to which crime or delinquency is
+based on heredity is far more questionable. Every student of genetics
+knows that we may have dwarf plants because the constitution of the germ
+is of a nature to produce only such individuals, or we may have dwarfed
+plants because of adverse conditions of soil and lack of an opportunity to
+climb or rise to their full capacity. Bateson pertinently remarks, "The
+stick will not make the dwarf pea climb, though without it the tall can
+never rise. Education, sanitation, and the rest are but the giving or
+withholding of opportunity." The important sociological question for us to
+determine is which of these lowly peas of the human family are really
+dwarfs and which are dwarfed simply because the stick of opportunity on
+which to climb is lacking.
+
+Beyond doubt a considerable portion of crime and degeneracy is due in
+large measure to innate inclination, but with just as little doubt much is
+the effect mainly of vicious habits acquired through an unwholesome
+environment. A normal appetite or impulse may be given a pathological
+trend by bad influences. And one has to reckon, moreover, with degrees of
+hereditary aptitude to crime. Just what is the measure of normality? To
+what extent by developing to their highest point certain inhibitive or
+opposing tendencies, can we counteract certain inherent proclivities for
+wrong-doing? By what means shall we sift the congenital defectives from
+the victims of suppressed opportunities? These and kindred questions
+confront us at the very outset of our studies of crime and delinquency. It
+is obvious that although we may institute the strictest elimination of the
+socially unfit, unless we can provide a wholesome environment for the fit,
+lapses into unfitness are sure to recur.
+
+=Feeble-Mindedness Often a Factor.--=The conviction is steadily growing
+among students of human heredity that a considerable amount of crime,
+gross immorality and degeneracy is due at bottom to feeble-mindedness and
+that, therefore, if we can once eliminate feeble-mindedness, these vicious
+accompaniments will at the same time in equal measure disappear. Goddard,
+for example, one of our authorities on the inheritance of
+feeble-mindedness, is convinced that a large proportion of the delinquent
+girls who fill our reformatories are actually feeble-minded. They are
+often the higher grade or moron type, and their mental condition remains
+unsuspected because they have never been thoroughly tested in this
+respect.
+
+=Many Delinquent Girls Mentally Deficient.--=According to Havelock Ellis,
+2,500 of some 15,000 women who passed through Magdalen homes in England
+were definitely feeble-minded and were known to have added a thousand
+illegitimate children to the population.
+
+The preliminary reports of the so-called white slave investigations now in
+progress in New York City classes 25 per cent. of these unfortunate women
+as mentally incapable of taking care of themselves. Other investigations
+indicate that from 40 to 60 per cent. of this class of women are
+defectives. For example, from the report of the Massachusetts "Commission
+for the Investigation of the White Slave Traffic, So-Called," one reads:
+"Of 300 prostitutes, 154, or 51 per cent., were feeble-minded. All
+doubtful cases were recorded as normal. The mental defect of these 154
+women was so pronounced and evident as to warrant the legal commitment of
+each one as a feeble-minded person or as a defective delinquent.... The
+135 women designated as normal, as a class were of distinctly inferior
+intelligence. More time for study of these women, more complete histories
+of their life in the community, and opportunity for more elaborate
+psychological tests might verify the belief of the examiners that many of
+them were also feeble-minded or insane."
+
+The data from some of our public reformatories, industrial schools and
+state homes for delinquent girls, are very instructive in this respect.
+Reports from a number of such institutions show that many of their inmates
+are mentally subnormal. The proportions range from thirty-three per cent.
+in the New Jersey Reformatory at Rahway to eighty-nine per cent. in the
+institution at Geneva, Illinois.
+
+=Institutional Figures Misleading.--=However, significant as are these
+figures from institutions for delinquents, one should not be misled by
+them. They are undoubtedly not representative of offenders in general, but
+of a selected group of the most hopeless cases. In the first place the
+more capable individuals escape the dragnet which lands the defective
+delinquents in an institution, and furthermore, because of liberal systems
+of probation, only the more incorrigible or the very stupid make up the
+bulk of the population of such places. Miss Augusta F. Bronner, assistant
+director of the Psychopathic Institute of the Juvenile Court of Chicago,
+from a careful study of five hundred and five cases of delinquent boys and
+girls in the Detention Home, chosen with as little selection as possible,
+finds the proportion of mentally subnormal among them to be less than ten
+per cent.
+
+=Many Prisoners Mentally Subnormal.--=Doctor Walter S. Fernald, of the
+Massachusetts School for Feeble-minded, estimates that "at least 25 per
+cent. of the inmates of our penal institutions are mentally defective."
+Among the various available estimates at hand this seems to be a fairly
+conservative approximation. Hastings H. Hart points out that this
+calculation of 25 per cent. means that there are 20,000 adult defective
+delinquents in prison, and 6,000 youths in juvenile reformatories, or a
+total of 26,000 in custody in the United States.
+
+=The Inhibitions Necessary to Social Welfare Not Well Established in
+All.--=But let us look at this matter of delinquency a little more in
+detail. In common with other living creatures mankind has two strongly
+predominating instincts without which there can be no prolonged individual
+or racial existence, namely, the self-preservative and the reproductive.
+Says Schiller: "While philosophers are disputing about the government of
+the world, Hunger and Love are performing the task." Under
+self-preservative would be included everything pertaining to food,
+property and self-protection. In addition, however, man, together with
+certain other social animals, has developed a third set of activities or
+instincts--an impulsion toward the preservation of the community to which
+he belongs--and so far has this evolved in his case that it outranks in
+importance the other two. For the highest accomplishments and ideals of
+the race are in last analysis expressions of this social instinct. But
+with this system of mutual help comes the necessity of certain restraints,
+because for society to exist its members must impose upon themselves, or
+have imposed upon them, certain inhibitions of their self-preservative and
+reproductive instincts.
+
+Being a late acquisition of the race and less firmly ingrained, the social
+instinct is not well established in all individuals. Some have it
+sufficiently strong to exercise of their own accord the necessary
+inhibitions of other instincts. Experience has shown that others, either
+through a lack or through a wrong cultivation of it, can not or will not
+do so unaided. For the latter, society has instituted certain conventions
+and the criminal law whereby through a system of restraints and
+punishments such an individual is held in check either by actual physical
+restraint of his property or person or through the powerfully inhibitive
+factors of shame or fear. Man as a normal member of society must
+constantly take heed of the physical, intellectual or moral danger the
+exercise of a given feeling, action or procedure on his part will bring to
+humanity, and govern himself accordingly.
+
+But it is in just these very inhibitions that mental defectives are
+lacking. They are almost invariably anti-social types because they are
+unable to establish the personal abstentions which are necessary for the
+good of the community. While in the individual of innate normal mentality
+anti-social traits may have developed because of improper training or
+surroundings, in mentally defective types some factor or factors necessary
+to normality have been left out of their make-up and as a result they are
+often wholly lacking in social instincts or have these so feebly developed
+that education and exhortations toward social ideals are fruitless. We can
+not appeal successfully if there is nothing to appeal to; we can not
+develop something out of nothing.
+
+=The High-Grade Moron a Difficult Problem.--=One great difficulty in
+identifying the high-grade morons who are a bountiful source of our
+criminals is our almost universal failure to recognize that a memory test
+alone is not sufficient to determine the mental responsibility of an
+individual. Not only memory, but judgment, will-power and perhaps, also,
+to a lesser degree, the powers of attention and concentration are all
+indispensable elements in the make-up of a normal individual. There are
+cases on record of imbeciles with prodigious memories, yet hopelessly
+incapable of caring for themselves or of respecting the rights of others.
+In fact certain types of morons, usually cunning, often prepossessing and
+superficially clever, are characterized by good memories and will
+_moralize_ volubly, although their wills are too weak to inhibit impulses
+when they face temptation. It is obvious that just in proportion as the
+intelligence of the high-grade degenerate approaches normality and yet
+remains abnormal, the more dangerous he may become to society.
+
+=Degenerate Strains.--=A number of family records are now available which
+show convincing evidence of the hereditary nature of a degeneracy which
+finds expression in pauperism, immorality and crime.
+
+As has already been pointed out, there is reason to believe that much of
+this is based in some degree on feeble-mindedness. One of the most
+remarkable of these is the recent study on degeneracy by Goddard as set
+forth in his book called _The Kallikak Family_. The record is that of six
+generations of descendants from an original progenitor to whom the
+fictitious name of Kallikak has been assigned. This individual, descended
+from good stock, before his marriage met a feeble-minded girl by whom he
+became the father of a feeble-minded son. Later he married a normal woman
+by whom he had normal children. Thus from one normal father have sprung
+two lines of progeny, one vitiated with feeble-mindedness, the other
+normal. The comparison may be readily made by drawing up in parallel
+columns the data as follows:
+
+            LINE A                                 LINE B
+
+  In five generations 480 direct     In five generations 496 descendants
+  descendants from a normal father   from the same normal father as in
+  father and a feeble-minded         Line A and a normal mother have the
+  mother have been accounted for     following record:
+  as follows:
+
+  143 known to be feeble-minded.     All but one of normal mentality.
+
+  291 mental status unknown or       Two men known to be alcoholic.
+  doubtful.
+
+  36 illegitimate.                   One case of religious mania.
+
+  33 sexually immoral, mostly        Among the rest have been found
+  prostitutes.                       nothing but good representative
+                                     citizenship, numbering doctors,
+  24 confirmed alcoholics.           lawyers, educators, judges,
+                                     traders, etc.
+
+  3 epileptics.                      No epileptics or criminals.
+
+  82 died in infancy.                Only fifteen children died in
+                                     infancy.
+
+  3 criminals.
+
+  8 keepers of disreputable houses.
+
+  46 only ones known to ben ormal.
+
+Certainly there is abundant food for thought in these two records.
+
+If we take still other families of criminal or degenerate antecedents the
+same multiplication of viciousness, as a rule, is in evidence. Thus,
+_Margaret, the Mother of Criminals_, has left a progeny of some 700
+paupers, prostitutes and criminals, some of the women bearing as many as
+twenty children. The famous Jukes family, so often cited, with its 310
+professional paupers, 300 deaths in infancy, 440 physical wrecks from
+debauchery, 50 prostitutes, 60 habitual thieves, 7 murderers, and 130
+other convicts out of a total 1,200 descendants who have been identified,
+has alone cost the state of New York $1,250,000 in the care of its
+criminal, defective and immoral progeny.
+
+Another family record, the Zeros, reported by Poellman, of Bonn, starts
+with a female confirmed drunkard. In six generations of her descendants,
+totaling 800 people, Poellman found 102 professional beggars, 107
+illegitimates, 181 prostitutes, 54 in almshouse, 76 convicted of serious
+crime, 7 of murder, and costing some $1,206,000. Or we might cite the
+so-called _Tribe of Ishmael_, the progeny of a neurotic man and a
+half-breed woman. They have spread their ill-favored spawn over various of
+the central states in a veritable flood of imbecility and petty crime. And
+to these families may be added the records of _The Hill Folk_, _The
+Pineys_, or others of the several recent studies of degenerate strains.
+All bear the same message of rapidly multiplying degeneracy.
+
+=Intensification of Defects by Inbreeding.--=Most of these regional
+surveys that are now in progress show that there is particular danger in a
+population becoming broken up into small communities and isolated. Under
+such conditions there is a pronounced tendency to intermarry, and if
+deterioration is already present in the stock such communities become
+centers of marked degeneracy. The situation is well exemplified in the
+following excerpt from Davenport:
+
+    "I have been going over the records of one family in New York, the
+    so-called Nam family. There were 55 per cent. consanguineous matings,
+    marriage between cousins, in one generation, and, owing to the fact
+    that the strain was already loaded with defects, we can see how these
+    defects were concentrated by these cousin marriages, so that about 90
+    per cent. of the strain is feeble-minded. There were fully 90 per
+    cent. of the men who are unable to resist the lure of liquor.
+    One-fourth of the children are born illegitimates. Infanticides,
+    incest, murder, harlotry, are all over the chart. This is a highly
+    inbred community, keeping a nearly pure strain of social defects, and
+    the cost to the community has been a million and a half on a fair way
+    of figuring, not directly in the care, but indirectly in the damage
+    they have done. These constitute a rural community. Out of this
+    community we can trace those who have gone to the cities and become
+    murderers, prostitutes and thieves. They are not confined to one
+    state; they spread out over the country. One branch of the family came
+    to the state of Minnesota. We sent to one of Doctor Rogers' trained
+    field workers to learn whether she had ever heard of this family, and
+    received a reply that the family was well known to social workers in
+    the state of Minnesota. These strains of degenerates are not local
+    matters at all; they are matters of national interest."
+
+Concerning crime and delinquency, we find that all evidence tends to show
+that an alarming increase is in progress although satisfactory data are
+hard to obtain. It is certain that there is a tremendously
+disproportionate increase in the number of prisoners in recent years
+compared with general population, for while the total population has
+increased three and one-half fold, the prison element has increased
+fifteen fold. According to Wier, in this country there are four and
+one-half times as many murders for every million of our population to-day
+as there were twenty years ago.
+
+It may be urged that this increase in prison population is not a
+disproportionate increase in the number of defectives or criminals, but
+only an increase in the number sent to prison, and this is probably a
+partial truth--but when we recall such pedigree as those of the Nams, the
+defective line of Kallikaks and other known unsound strains, he must be
+hopeful indeed who can find much consolation in this supposition. In any
+event, no such uncertainty exists regarding the number of murders and
+homicides, since these have in all probability been as fully recorded in
+the past as at present.
+
+=Vicious Surroundings Not a Sufficient Explanation in Degenerate
+Stocks.--=It is sometimes urged that we are not dealing in such cases with
+degenerate strains, but merely with unfortunate individuals who have been
+subjected to pernicious surroundings from the beginning. And it can not be
+denied that parents who are mentally defective, dissipated or syphilitic
+afford most noxious developmental and environmental conditions for their
+children. But when one notes how intimately the moral degeneracy in such
+stocks is bound up with some degree of feeble-mindedness, he is strongly
+skeptical toward the sufficiency of such an interpretation, although
+environment undoubtedly intensifies the results. Concerning this point
+Davenport says:
+
+    "We have certain methods of testing whether it is bad environment or
+    bad breeding which produced these people. Some of the children have
+    been taken at an early age and 'placed out'. We have traced their
+    subsequent history. In most cases they have turned out quite as bad as
+    those who have remained at home. In a few cases they have turned out
+    well, but it is also true that some of the children who remained at
+    home in bad environment have turned out well."
+
+And to Davenport's testimony may we add that of Doctor Wilmarth, who,
+speaking of children at the home for feeble-minded, says:
+
+    "In no place is this subject of the power of heredity in relation to
+    environment so easily studied as among our children. A group of many
+    little children came to us from the state school, being untrainable
+    there. They have had with us the same teaching and the same
+    companionship. Each one has lived, eaten and slept among the others,
+    and, so far as we know, with but one exception, those of vicious
+    parentage have turned instinctively to vicious traits by preference,
+    while those of simple but honest stock do evil things only under
+    strong temptation, and do not persist in them after the wrong is
+    pointed out."
+
+=By No Means All Delinquents Are Defectives.--=One must not overlook the
+fact, however, that _delinquent_ and _defective_ are by no means
+synonymous terms, and that many delinquents are with little doubt the
+product of adverse social circumstances.
+
+The recent careful work of Doctor William Healy[13] in connection with the
+juvenile delinquents of Chicago shows convincingly that the underlying
+causations of delinquency are many. Such factors as immorality or constant
+quarreling of parents, bad companions, lack of parental control, defective
+sense organs, debilitating habits, lack of healthy mental interests and a
+host of other environmental factors are not infrequently sufficient in
+themselves to develop delinquency in the absence of inherited deficiency.
+The present-day efforts of the student of heredity should not be
+misunderstood. They are not attempts to make all delinquents out
+defectives, but rather to determine what percentage of delinquents may be
+legitimately reckoned as defective and to make the facts known. Since
+there is no longer any reasonable doubt that, to express it in the mildest
+terms, an amount of delinquency far from negligible is due in great
+measure to congenital omissions or propensities, then the sooner the
+public learns this the better, for we may then set about supplementing our
+present efforts at race betterment through external improvement by
+devising means of cleansing the fountain source as well.
+
+It can scarcely be doubted that the average man differs little if any in
+inherent personality and capacity from many a criminal who is such by
+occasion rather than by undue predisposition. Who can truthfully answer
+how many individuals there are who are not potentially criminals to some
+extent, given sufficient evocative conditions of ignorance, vice, adverse
+economic pressure and undue temptation?
+
+  "Virtue itself turns vice, being misapplied."
+
+=No Special Inheritable Crime-Factor.--=The main difficulty in trying to
+find a hereditary basis for crime lies in the multiplicity of things crime
+may be. The individual impulsions which lead to certain offenses may be
+utterly different from those which conduce to others. Undoubtedly many
+inborn tendencies which are perfectly normal or neutral in themselves may
+be warped by circumstances into the commission of what are classified as
+crimes. The moral man may have the same desire for a thing that the
+criminal does, but when he finds that this desire can only be gratified by
+injury to others, he inhibits it because of his repugnance to such injury.
+The criminal makes no such inhibition.
+
+In general, crime means an offense of some kind against person, property
+or state. But a biological analysis of it, could it be made, would require
+among other things knowledge of crime in terms of motive or lack of
+motive, whether the act was intended to benefit the perpetrator, some
+other person, or even the race or state; whether the offense was one of
+dishonesty, of cupidity, of lust, or of violence against another.
+
+As a matter of fact no satisfactory classification of crime can be made
+since so many factors enter and in such varying degrees. Most
+classifications made in our legal codes are a hodge-podge based on a
+mixture of motive on the part of the participant, degree of turpitude
+involved, nature and extent of the injury inflicted, and the object
+against which the offense was perpetrated, whether an individual, society
+or the state. Moreover, it must not be forgotten that in many instances
+what was crime in the past is no longer so, and vice versa many things
+which are regarded as criminal to-day were not considered so in the past.
+So the futility of seeking a specific inherent propensity for "crime" is
+manifest. How, for instance, in terms of hereditary determiners shall we
+draw the fine lines of distinction among those who bribe legislators and
+legal officials, those who are avaricious and dishonest in the world of
+trade, and those who are wilfully obtuse in providing proper safeguards
+for employees?
+
+=What Is Meant by a Born Criminal?--=All we can do is to fall back on the
+assurance that any act directly or indirectly injurious to society is an
+offense, and that those offenders who are congenitally unable to
+distinguish between what is generally accepted as right and wrong, or who
+if recognizing this are nevertheless uncontrollably impelled toward or are
+unable to refrain from anti-social acts because of some inherent condition
+of intellectual or volitional make-up, may be legitimately classed as
+individuals born with an aptitude for crime and social transgressions. In
+such individuals the natural mental make-up is lacking in some of its
+necessary elements so that memory, judgment, or will-power are not up to
+the minimum that is necessary for the establishment of proper conduct. In
+some cases, apparently, this lack finds expression in almost any kind of
+vice or crime into which circumstances happen to lead the individual. In
+others, however, there seem to be tendencies toward the commission of
+certain types of crime or vice. Certain family strains are characterized
+by petty thieving, others by deeds of violence, and still others by sexual
+offenses. Certain types of mental defect are closely associated with
+certain crimes. Thus sufferers from incipient paresis seem particularly
+prone to commit assaults and larceny; epileptics, crimes of brutality and
+violence.
+
+=The Epileptic Criminal Especially Dangerous.--=One of the characteristics
+of epilepsy, indeed, emphasized by various psychiatrists, is that
+frequently it leads to loss of those forms of self-restraint which are
+absolutely indispensable to morality and the safety of society. Cruelty,
+atrocious sexual offenses and other vicious crimes are the result. It is a
+noteworthy fact, moreover, that often in the milder forms of affliction,
+where instead of well-marked convulsions only momentary lapses of
+consciousness occur, the greatest amount of mental and moral deterioration
+and fluctuation is sometimes found.
+
+The situation as regards the epileptic is well presented by Doctor William
+Healy, Director of the Juvenile Psycopathic Institute of Chicago, in an
+article entitled "Epilepsy and Crime; the Cost", in the _Illinois Medical
+Journal_, November, 1912. He says:
+
+    "In the work of our institute,[14] which represents the most
+    thoroughgoing research into the genetics of criminalism ever
+    undertaken in this country, we have with the help of parents and
+    others carefully studied nearly 1,000 young repeated offenders. We
+    have found that no less than 7-1/2 per cent. of these are ordinary
+    epileptics, and we have reason to suspect others. This by no means
+    represents the total number of epileptics seen in connection with
+    juvenile court work, where, of course, first offenders as well as
+    large numbers of dependents are seen. In addition to my above
+    enumeration, other cases seen by the Detention Home physicians and
+    myself amount up to many scores of cases. If one remembers that it is
+    ordinarily calculated that one person in every 500 is epileptic, the
+    significance of this high criminal percentage is clear, and the
+    practical bearing of it is still further accentuated by the fact that
+    some of the worst repeaters are epileptics, and that many of the
+    gravest crimes are committed by those unfortunates. The connection
+    between epilepsy and crime has everywhere been recognized by students
+    of the subject, but it apparently needs constant emphasis in order
+    that common sense steps may be taken toward guardianship of these who
+    suffer from a disease which wreaks such extravagant vengeance on
+    society."
+
+=Mental Disorders Most Frequently Associated With Crime.--=Doctor Charles
+Mercier, an English authority on crime and insanity, in enumerating the
+mental disorders most frequently associated with crime, places the
+insanity of drunkenness first. Any one who will take the trouble to verify
+the facts in his own community will find that a large percentage,
+frequently considerably over half, of the arrests made by the police are
+for acts committed while the offender was more or less under the influence
+of alcohol. Next to drunkenness among mental disorders which lead to crime
+Doctor Mercier places feeble-mindedness. Next to feeble-mindedness comes
+epilepsy; then paranoia or systematized delusion; next paresis; and lastly
+melancholia.
+
+Paranoics are peculiar in that they are particularly apt to attack persons
+of prominence. Highly egotistical, they almost invariably believe
+themselves or some one or some cause dear to them, the subject of a plot,
+perhaps to rob them, to torture them, to steal their inventions or
+literary productions, or to persecute them in some way. Two if not three
+of our murdered presidents owe their assassinations to paranoics. Many
+rulers have been attacked and some killed by such insane individuals. Most
+of the "cranks" who write threatening letters are lunatics of this type.
+
+Of the kinds of mental unsoundness known to be inheritable which are of
+special significance from the standpoint of crime and delinquency
+undoubtedly feeble-mindedness ranks first. We have already seen that as
+our methods for detecting the higher grades of feeble-mindedness become
+more accurate we disclose in border-line cases a veritable hot-bed of
+mental incapacity suitable for the engendering of the criminal and the
+vicious. Here in addition to some of the more pronounced criminal types
+belong hosts of our chronic petty offenders, our sexually vicious and our
+"won't-works". One interesting outcome of a recent investigation into the
+army of unemployed in England was the discovery of the general unfitness
+of these unemployed. In our own country the habitually unemployed are so
+not because of lack of work, but largely because it is unprofitable to
+employ them.
+
+=The Bearing of Immigration on Crime and Delinquency.--=Perhaps in no
+field more than this of crime and delinquency, especially in so far as it
+is based on innate deficiency, does the gravity of the immigration
+question impress itself on us. How stupendous this problem[15] has become
+may be realized from the fact that according to the census of 1910,
+13,345,545, or one out of seven of the inhabitants of the United States,
+were foreign born. And if we add to these the 18,897,837 of whom one or
+both parents were of foreign birth, we reach the astonishing total of over
+32,000,000, or more than one-third of our total population, who are
+foreign born, or who have one or both parents of foreign birth.
+
+During the decade from 1900 to 1910, 8,500,000 foreigners came to the
+United States, of whom 5,250,000 remained to make a permanent home. This
+shows how rapidly our whole population might be radically changed. In
+recent years the source of our immigrants has shifted proportionately from
+northwestern Europe to southern and eastern Europe (Italy, Austria-Hungary
+and Russia), and whether for weal or woe this new blood must inevitably
+leave its impress upon us. Does it not behoove us then to seek with
+anxious eyes some knowledge of these invading hordes with whom we are to
+mingle our life-blood?
+
+Even the most superficial examination may well cause us grave concern. We
+find that in one year (1908) at Ellis Island alone, 3,741 paupers, 2,900
+persons with contagious disease, 184 insane, 121 feeble-minded, 136
+criminals, 124 prostitutes and 65 idiots were denied entrance, and yet,
+according to the estimate of Doctor F. K. Sprague, of the United States
+Public Health Service, probably only about 5 per cent of the mentally
+deficient and 25 per cent. of those who will become insane have been
+detected. When confronted by such data we can begin to realize what we are
+facing. Others estimate that from 6 to 7 per cent. of the immigrants who
+are now arriving are feeble-minded. We learn further that recently while
+the foreign-born population of New York state was about 30 per cent., the
+foreign-born population of the insane hospitals of the state was over 43
+per cent., and at one time approximately 65 per cent. for New York City.
+In one year (1908) 84 per cent. of the patients in Bellevue Hospital, New
+York City, were of foreign parentage. Paresis, which probably always has
+syphilis as its antecedent, is proportionately twice as prevalent among
+foreigners as among natives in New York City.
+
+But from the standpoint of inheritance, however great the danger may be
+from classifiable defectives, it is probably far greater from that much
+larger class of aliens we are now receiving with open arms who are below
+the mental and physical average of their own countries. Moreover, with our
+present system of inspection there is no way of detecting the grades of
+feeble-mindedness above idiocy and imbecility in the great numbers of
+foreign children under five when brought in, who are beginning to show up
+in alarming numbers in the schools of some of our larger cities. About
+thirty per cent. of the annual increment of our population is due to
+immigration and not to births; and once in our country the alien far
+outbreeds the native stock, with relatively little increase in death-rate,
+thus making a double contribution to the increase of population. When we
+take all these facts into consideration it certainly is high time that we
+arouse from our self-complacent attitude and consider the whole question
+of immigration most earnestly.
+
+In spite of the fact that many individuals are caught in the net of
+inspection at our portals, it is clear that still more rigid rejection[16]
+is imperative. The inspectors at our various ports are doing the best
+they can under the circumstances, but there are at present too few of them
+and they are too restricted in their powers to meet the situation
+satisfactorily. Moreover, when at one of our ports in one year (1910), of
+1,483 immigrants certified by the inspecting surgeons as unfit to land
+because of serious mental or physical defects, 1,370 were landed anyway,
+it is evident that there is a strong and reprehensible pull somewhere to
+evade the obvious intent of the law.
+
+It remains for us as a people to decide whether we shall continue to let
+the large employers of cheap labor, the railroad and steamship agents and
+brokers, who care nothing about the innate fitness of the immigrants they
+bring, determine the character of our future population, or whether we
+shall insist on a proper regulation of this flood so that we may receive
+only an honest, intelligent, industrious and healthy stock. To continue to
+absorb these aliens with as little selection as we now do is nothing short
+of criminal carelessness. Let us not be deceived by the promptings of a
+misguided sentiment, "The voice is Jacob's voice, but the hands are the
+hands of Esau." The voice is Jacob's voice, nor should this voice of the
+easily persuaded, the sentimentalist, the interested organization to which
+the relatives of the defective alien belong, or any other pressure move us
+from our obvious duty of refusing to fasten upon this country an incubus
+of degeneracy for which we as a nation are in no way responsible.
+
+To render us safe we should not only have more carefully drawn laws and
+more rigid selection at our ports of entry, but we should if possible
+also know the stock from which our future citizens come. This is
+peculiarly desirable for such defects as feeble-mindedness and various
+other mental imperfections, some of which require prolonged observation
+for detection. Davenport estimates that it is wholly within the realm of
+possibility and good business sense to maintain a corps of trained
+inspectors abroad in the chief centers from which our immigrants come who
+shall certify the desirable applicants. He makes the point that the
+national expense would be far less than the cost of maintaining the army
+of defectives we are now admitting to our own country, many of whom almost
+immediately become public charges, to say nothing of the hordes of
+carriers who though normal themselves, will transmit undesirable traits.
+
+=Sexual Vice.--=As to sexual vice, the skein is indeed a tangled one.
+Since nine-tenths of the difficulty centers in a lack of self-restraint,
+and inasmuch as the mating instinct is one of the strongest that tugs at
+the flesh of humanity, it is obvious that those by nature deficient in
+volitional control will almost without exception give way to the call. So
+as might be expected the hordes of our feeble-minded and epileptic are
+always a source of grave danger in this respect. However, the mentally
+enfeebled are by no means the only offenders; indeed, they are probably
+not the majority. The true situation is finally dawning on society and the
+reformer's call for instruction in "sex-hygiene" resounds through the
+land. The whole matter is one of the most perplexing and momentous that
+confronts us to-day.
+
+=The Question of School Instruction in Sex-Hygiene.--=While the writer
+does not for an instant underestimate the gravity of the situation, and
+has only contempt for the nonsense that is palmed off on children about
+their origin, or the indelicate self-consciousness which puts under the
+ban the discussion of so serious a problem by adults, still he is not
+convinced that the universal teaching of the subject to children in
+schools by the average teacher, as advocated by some, is to be the
+solution of the matter or is even a wise attempt at solution. Yet he
+freely admits that he is possibly overfearful of the effects of the
+undesirable features of such instruction. True it is that all children do
+learn, frequently at an astonishingly early age, about sex, and their
+knowledge is usually of an undesirable kind from unreliable and often
+vicious sources, and it is equally true that parents, either through
+ignorance or prudery, generally can not be depended on to give the child
+necessary instruction. But before entering on a wide-spread campaign of
+undiluted sex-instruction in schools might it not be more prudent to make
+an attempt toward reaching fathers and mothers and convincing them of the
+necessity of dealing more frankly and intelligently with their children
+regarding sex?
+
+Even to the novice in psychology the powerful nature of suggestion is
+known, and with this knowledge before us, is it not wiser to strive in the
+main to keep the child's mind off of sex rather than specifically to focus
+it on it by special convocations and discourse? If our psychology means
+anything, then the worst possible thing we can do for a child is to make
+him unduly sex-conscious. Something might be done profitably perhaps in
+schools in an unobtrusive way by specially gifted persons, but the
+self-conscious way in which most teachers go about topics of sex is
+certainly not reassuring to the thoughtful observer as regards the benefit
+derived from such instruction. The one evident method of accomplishing
+wholesome sex-instruction in schools, devoid of all possibility of
+undesirable suggestion and sex-consciousness, is in the form of biological
+work where plants and animals are studied in all their relations, the
+subject of propagation being taken up in as matter-of-fact a way as the
+functioning of any other organ system of plants or animals. In such a
+course, long before the subject of sex in higher animals need be
+approached the pupil will have developed an attitude of mind which will
+lead him to see nothing unusual or suggestive in the function of sex no
+matter where it may be found. Incidentally, inasmuch as the manner in
+which germs affect living organisms should be studied in such a course
+anyway, it would be a simple matter to give all necessary information
+about the dangers of infection from venereal diseases.
+
+=Mere Knowledge Not the Crux of the Sex Problem.--=However, desirable as
+correct knowledge about sex is, knowledge alone is not the crux of the sex
+problem. The moral dangers and abuses that we are trying to circumvent lie
+rather in the realm of the emotions than that of the intellect. The
+problem must be solved from a broader foundation than mere information.
+The all-important consideration is the early establishment of general
+habits of self-control so that these may become incorporated in the
+nervous organization of the child and become inhibitory anchors against
+passions and temptation. Children must be taught to suppress the present
+impulse, to sacrifice the immediate pleasure for the more distant or
+permanent good. They must be practised in calling up feelings that will
+counteract other promptings which if followed blindly are inimical to
+social welfare. Their control must come from within not as a matter of
+external compulsion. That way character lies.
+
+So in viewing the problem of sexual hygiene the writer feels that our
+attempts toward damming the torrents in the adolescent by a belated effort
+at verbal instruction on sex-hygiene is at best only a palliative or an
+attempt to cure the symptoms of a more deeply-seated, organic, social
+malady. The treatment should have been in progress long before in the form
+of training in self-control, and in the inculcation of the sense of
+dignity and self-respect which springs from the individual's consciousness
+of being, not a slave to his desires, but his own master. This, together
+with the judicious schooling of boys in a greater chivalry and respect for
+womanhood, and of girls in the necessity of meriting such esteem, will, in
+my estimation, carry us further than formal courses in sex-hygiene.
+
+=Early Training in Self-Restraint an Important Preventive of Crime and
+Delinquency.--=As to crime and delinquency in general, it is evident that
+the same early training in self-restraint is a most important factor of
+prevention. A wise warden in charge of a large prison says, "Most of these
+men are here because they have not learned sufficiently the lesson of
+self-control." This is the age of preventive medicine, why not also of
+preventive crime and delinquency? Instead of confining our practise to
+punishing offenders, necessary as this may be under the present
+conditions, why not strive more to prevent the commission of offenses? As
+far as normal individuals are concerned much can be done by early
+cultivation in self-discipline and through the establishment of moral
+backbone by training in the overcoming of difficulties. Much, very much,
+also remains to be done in the correction of wrong social conditions.
+
+=Unpardonable to Permit Delinquent Defectives to Multiply Their Kind.--=As
+for our mental defectives and moral imbeciles, knowing now how strongly
+hereditary the underlying factors of these conditions are, and with no
+preventive or curative agents in sight, to let them produce progeny, is
+clearly unpardonable.
+
+
+
+
+CHAPTER X
+
+RACE BETTERMENT THROUGH HEREDITY
+
+
+Most of us have heard in one form or another the fairy story of the youth
+on adventure bent, who was captured by the giant and under dire penalty in
+case of failure was set the task of sweeping out the giant's stable before
+sundown. The peculiarity of this stable, it will be recalled, was that, as
+fast as the refuse was swept out at the door an even greater quantity
+poured in through the windows so that the sweeper, just in proportion to
+his zeal, became more and more encumbered with his burden.
+
+=A Questionable Form of Charity.--=Though we smile at the childishness of
+this legend, are we not as a civilized people attempting through our
+charities a feat parallel to that of this unfortunate youth? We foster and
+favor our social wastage with the inevitable result that it runs riot
+under our sheltering hand and deluges us with an ever accumulating flood
+of its like. For are we not constantly building more asylums, sanitaria
+and prisons, to preserve more unfit, to produce more defectives, to
+require still greater numbers of asylums, sanitaria and prisons, to
+preserve more unfit, and so on in unending progression?
+
+At nearly every period of history there have been certain individuals who
+have seen the necessity of a state eliminating its supply of defectives.
+
+=Past Protests.--=For instance, we find the importance of this strongly
+urged by Plato. After pointing out the fact that the shepherd, in order to
+maintain the standard of his flocks, bred only from the best individuals,
+as did likewise the huntsman with his dogs and horses, and the fancier
+with his various pets, Plato went on to show the danger to the state of
+allowing the constantly increasing body of defectives and degenerates to
+multiply their kind. Repeated expression of the same idea has occurred
+from time to time during the succeeding centuries.
+
+Little heed was paid to these remonstrances, however, with the result that
+is known to us all. To-day, "the glory that was Greece and the grandeur
+that was Rome" is still sung by the poet, but the original nations
+themselves have long since passed into the night.
+
+=An Increasing Flood of Defectives.--=Strive to ignore the unpleasant
+facts as we may, we have to admit that the same problem of what the human
+harvest shall be is with us in grave form to-day. The alarming phase of
+the situation, however, lies in the fact that we are facing an ever
+increasing flood of social wastage.
+
+But _why_ this increase of defectives? It can not be attributed to
+oppression, to grinding poverty, or to decline in attention to our sick
+and needy, for never was prosperity greater, never were charities more
+flourishing, never such activity in the search for palliatives and cures.
+The simple fact is that we are breeding our defectives. The human harvest
+like the grain harvest is based fundamentally on heritage. And to get a
+better crop of human beings, we must, as with other crops, weed out bad
+strains.
+
+To whatever source of information we turn the facts are essentially the
+same. Abroad we find that in England, for example, the ratio of defectives
+to normals more than doubled between 1764 and 1896. At home, from the
+investigation of Davenport and Weeks we learn that in the state of New
+Jersey the number of epileptics doubles every thirty years. And other
+investigators estimate that the fecundity of mental defectives in general
+is about twice as great as that of the average of our population. In a
+recent report of the New York State Board of Charities we read, "There are
+about thirty thousand feeble-minded persons in the state of New York, of
+whom four thousand are intermittently sequestered while twenty-six
+thousand who are a menace to society are at liberty and may produce the
+unfit." And a passage from the last Massachusetts report reads as follows:
+"We have been obliged to refuse a very large number of applicants for the
+admission of feeble-minded women--many of whom have given birth to one or
+more children. The prolific progeny of these women almost without
+exception are public charges from the date of their birth."
+
+How fertile defective types may be is shown by a passage in one of Doctor
+Wilmarth's papers which runs as follows: "One feeble-minded woman, now
+removed from this state, had by different men eighteen children in
+nineteen years, she alleges." In a letter Doctor Wilmarth tells me that
+the birth of the twenty-third child of this woman has just been
+announced! In one English workhouse Potts reports sixteen feeble-minded
+women who have produced one hundred sixteen mentally defective children,
+and Branthwaite ninety-two female habitual drunkards who have had eight
+hundred fifty babies. If we include the two million individuals cared for
+annually in various institutional homes, hospitals and dispensaries as
+dependents, the estimated total of insane, feeble-minded, epileptic, deaf
+and dumb, criminals, juvenile delinquents, paupers and other dependents in
+the United States in 1910 was approximately three million, or one in every
+thirty of our population! With the higher fertility of certain of these
+classes and with only a small percentage under custodial care where will
+it all end? Is it not time for us to waken from our lethargy and stem this
+tide of national deterioration?
+
+=Natural Elimination of Defectives Done Away With.--=With our improved
+methods of sanitation and care of the sick, the pauper and the defective,
+these classes have been freed from the stress of an environment that under
+natural conditions would have resulted in their premature death and
+consequent infertility. Or in the terminology of the biologist, we have
+done away with the factor of _natural selection_, the factor which in
+state of nature keeps all races purged of the unfit, the ill-adapted. With
+this restraining, and purifying influence removed, however, the weakling,
+the defective, may arrive at maturity and commingle his blood with that of
+the strong, with the inevitable result that the general vigor of the
+progeny from generation to generation is sapped and progressively
+undermined. Thus we are confronted by the stubborn fact that through
+present humanitarian methods we are driving the race toward decadence.
+
+=Why Not Prevent Our Social Maladies?--=Now there is no reasonable person,
+I think, who will not admit that the motives underlying our modern
+altruistic practises are the noblest fruitage of our slow upward struggle
+from the brute to man. As humane beings, we can not cast aside these
+principles and return to the painful and pitiless method of nature which
+would leave the sick and the defective alone to perish miserably; the
+sacrifice would be too great.
+
+Is there then no escape from this dilemma? To this query the modern
+student of heredity answers yes; let us but add more wisdom to our charity
+and the enigma is solved. We need no sacrifice of pity but rather an
+expansion of it. Let us but extend our vision from immediate suffering to
+the prospective suffering of the countless unborn descendants of our
+present unfit and ask ourselves the question, why should they be born? Why
+not prevent our social maladies instead of waiting to cure them? This is
+the province of eugenics.
+
+=Eugenics Defined.--=The term Eugenics was coined in 1883 by Francis
+Galton in his book entitled _Inquiries Into Human Faculties_, and we may
+therefore look to him for a satisfactory definition. He says, "Eugenics is
+the study of the agencies under social control, that may improve or impair
+the racial qualities of future generations, either physically or
+mentally." And again, "I take Eugenics very seriously, feeling that its
+principles ought to become one of the dominant motives in a civilized
+nation, much as if they were one of its religious tenets.... Man is gifted
+with pity and other kindly feelings, but he also has the power of
+preventing many kinds of suffering. I conceive it to fall well within his
+province to replace natural selection by other processes that are more
+merciful and not less effective. This is precisely the aim of Eugenics.
+Its first object is to check the birth-rate of the unfit instead of
+allowing them to come into being, though doomed in large numbers to perish
+prematurely. The second object is the improvement of the race by
+furthering the productivity of the fit, by early marriages and the
+healthful rearing of their children."
+
+=Improved Environment Alone Will Not Cure Racial Degeneracy.--=While many
+an enthusiastic humanitarian is laboring under the assumption that if we
+can improve external conditions human deficiencies will disappear, the
+student of heredity realizes that this is in large part a delusion unless
+we can secure an accompanying improvement in intrinsic qualities of the
+human species itself through the suitable mating of individuals. Just as
+the intelligent farmer to-day demands selected seed as well as good soil
+and proper cultivation, so one with the facts of heredity at hand would,
+as he views social problems, urge the fundamental importance of having
+selected stock with which to start. No shifts or shapings of environment
+will ever enable men to "gather grapes of thorns or figs of thistles."
+
+=Heredity and Environment.--=To wrangle over the question of which is the
+more important, heredity or environment, is about as idle a proceeding as
+to argue which is the more important, the stomach or something to put in
+the stomach. Man would soon come to grief without either. So, too, the
+question of human development is not one of heredity alone nor of
+environment alone; both are necessary and must work hand in hand. Dormant
+capacities must have proper environment to call them forth, but on the
+other hand no kind of environment can evoke responses if some degree of
+aptitude is not present.
+
+Professor Thorndike undertook experiments with groups of school children
+of high and of low initial ability respectively to determine whether equal
+opportunity or equal special training would produce an equalizing effect
+in easily alterable traits such as rapidity in addition and the like.
+Without exception he found that at the end of such experiments, although
+both groups had improved, the superior individuals were farther ahead than
+ever, that equality of opportunity and training had widened rather than
+narrowed the gap between the two classes. Others who have made special
+studies on the causes of individual differences have come to the same
+conclusion; namely, that individuals differ widely by original nature and
+that similarity in conditions of nurture and training will not avail in
+deleting these differences.
+
+Galton and others, from extensive studies based on English sources, have
+shown that notable achievements have run in certain families to a degree
+that is inexplicable on the basis of opportunity alone; it can be fully
+accounted for only by attributing much to superior inborn capacity. Doctor
+Woods has shown much the same thing for certain families in America.
+Schuster and Elderton have proved that there is a high degree of
+similarity in scholastic standing between fathers and sons in Oxford.
+Professor Pearson's measurements of mental characters in brothers and
+sisters while at school show a high degree of innate resemblance in many
+cases and certain cases of decided contrast. Where contrasts exist in
+certain families they remain unreduced in spite of the similarity of
+environment, thus proving that environment is less operative in the final
+intellectual establishment of such individuals than are their inborn
+aptitudes. Even in twins, as both Galton and Thorndike have shown, there
+is no tendency for similar education, home life and the like to render
+those originally different any more similar with advancing years.
+
+Professor Karl Pearson has done more perhaps than any other individual
+toward attempting actually to measure the relative strength of heredity
+and environment. Numerous statistical measurements lead him to conclude
+that it is a conservative estimate to regard heredity as at least five or
+ten times as important as environment in the development of the
+individual. A vigorous defense by him of this position will be found in
+_Biometrika_ for April, 1914.
+
+=Inter-Racial Marriage.--=Some of the dangers of racial deterioration
+which threaten us because of our laxity regarding immigration have already
+been indicated. It is high time that we give this whole question the most
+serious consideration of which we are capable. From the rate at which
+immigrants are increasing it is obvious that our very life-blood is at
+stake. For our own protection we must face the question of what types or
+races should be ruled out. Aside from the dangers which lie in the
+defective or unsuccessful types already discussed in Chapter IX, many
+students of heredity feel that there is great hazard in the mongrelizing
+of distinctly unrelated races no matter how superior the original strains
+may be. Unfortunately there is a great lack of reliable data on this
+point. The mulatto of our own country, the Eurasians in India and the
+mixed races of South America are, according to the testimony of many
+observers, eloquent arguments against such hybridization. Agassiz remarked
+on this point as follows:
+
+    "Let any one who doubts the evil of the mixture of races and who is
+    inclined from mistaken philanthropy to break down all barriers between
+    them come to Brazil. He can not deny the deterioration consequent upon
+    the amalgamation of races, more wide-spread here than in any other
+    country in the world, and which is rapidly effacing the best qualities
+    of the white man, the Indian, and the negro, leaving a mongrel
+    nondescript type deficient in physical and mental energy."
+
+Of the American mulatto one not infrequently meets with the assertion that
+he is on the average inferior mentally, morally and physically to either
+the white or the negro race. Thus Doctor J. B. Taylor[17] states that,
+"It is demonstrated by well-attested facts that these hybrids of black and
+white are vastly more susceptible to certain infections; their moral as
+well as physical stamina is lower than that of either original race."
+Others would deny that conclusive evidence to this effect exists. However,
+it is certain that under existing social conditions in our own country
+only the most worthless and vicious of the white race will tend in any
+considerable numbers to mate with the negro and the result can not but
+mean deterioration on the whole for either race.
+
+There is certainly not one iota of evidence that the crossing of any two
+widely different human races will yield superior offspring in any respect
+and there are many indications that such intermixture lowers the average
+of the population. Our evidence derived from plant and animal breeding is
+also against pronounced crosses. The inferiority of the mongrel is
+universally recognized. No sane farmer, for example, would seek to improve
+his Jerseys or his Herefords by crossing one with the other. It is true
+that in pure breeds of plants and animals we sometimes venture on a cross
+to introduce some new desirable character but we follow up such mixture by
+a rigid selection in which is eliminated all but the rare individuals
+having the desired characteristics, and we continue this elimination
+generation after generation to fix our characters again. It is obvious
+that no such selection as this would be possible among the progeny of
+human crosses.
+
+It clearly becomes our duty then to determine as accurately as possible
+the degree of non-relationship between races it is inadvisable to
+transcend in inter-racial marriages. We are certainly taking great risks
+in accepting in any considerable numbers those races we can not assimilate
+to advantage into our own stock.
+
+=War.--=The deteriorating effect of war on national physique and vigor has
+been so frequently cited by eugenists[18] and is so obvious as scarcely to
+require further comment. It should be pointed out, however, that where, as
+is the case at present in Great Britain, armies are assembled from
+volunteers, instead of by conscription, there is the greatest danger from
+the eugenic standpoint, since not only physical but moral qualities are
+involved. For it is the brave, the generous, the individual with a high
+sense of duty who goes forward to the slaughter leaving the cowardly, the
+selfish or the indifferent to father the race. With the awful deadliness
+of modern warfare upon exhibition before our very eyes to-day, the extreme
+seriousness of such selective action must be evident to every thoughtful
+person.
+
+=Human Conservation.--=We talk much in recent years of _conservation_; but
+what are our forests and frontiers, our minerals and our waterways,
+compared with our national health and life-blood? No farmer would think of
+setting aside a diseased or physically defective _animal_ for breeding
+purposes, yet the same man together with the majority of mankind is wholly
+oblivious to similar faults when it comes to the mating of human beings.
+But is it not as important to look to fitness in man as in Poland China
+hogs or Holstein cows? Certainly the various strains are as marked and
+breed as true in the human family as in our live stock. Why face
+complacently in our own families what we would not tolerate in our
+piggery?
+
+From the expenditure of comparatively small sums in studying the
+inheritance of various qualities in wheat, corn and other grain,
+improvements based on the laws of genetics have been secured which are
+enormously increasing our agricultural output and thereby adding to our
+national wealth. But if it costs relatively little to discover and
+conserve millions of dollars' worth of hereditary qualities in our plants
+and animals, what are we to think of ourselves, an intelligent people who,
+knowing that "every good tree bringeth forth good fruit, but a corrupt
+tree bringeth forth evil fruit," still go on placidly permitting the
+production of defectives and delinquents? Can we continue to drink the
+sluggish blood of the pauper and the imbecile into our veins and hope to
+escape unscathed?
+
+We are all familiar with the fate of Babylon, Assyria, Persia, Egypt and
+Rome. Why not America? Certainly we have no pledge of special immunity
+from Divine Powers. If so, what then is the meaning of our 366 hospitals
+for insane which cost us annually $21,000,000; our 63 institutions for
+feeble-minded costing us over $5,000,000; our 1,300 prisons maintained at
+a cost of more than $13,000,000; our 1,500 hospitals whose annual
+maintenance requires at least $30,000,000; our 115 schools or homes for
+deaf and dumb; our 2,500 almshouses with an annual expense account of
+$20,000,000 and our 1,200 refuge homes costing annually several millions
+of dollars more? To say that we spend annually over $100,000,000 on the
+custody of insane, feeble-minded, paupers, epileptics, deaf, blind and
+other charges is expressing the situation very conservatively.
+
+=Kindness in the Long Run.--=There is no one I think who will not admit
+that the sympathy and charity of the human heart are its noblest virtues.
+But we must face the problem of what is kindness in the long run. Havelock
+Ellis well says, "The superficially sympathetic man flings a coin to the
+beggar; the more deeply sympathetic man builds an almshouse for him so
+that he need no longer beg; but perhaps the most radically sympathetic of
+all is the man who arranges that the beggar shall not be born."
+
+What shall we do?
+
+=The Problem Has Two Phases.--=For an intelligent consideration of the
+problem one must recognize at the outset that it has two distinct phases;
+namely, (1) a selective union of the fittest, or in other words, a
+conscious attempt to breed a superior race; and (2) the elimination of the
+obviously unfit by preventing their reproduction, with the purpose of
+purifying the present race. It is evident at a glance that these are two
+essentially distinct problems although the practise of either method could
+result in racial improvement. The first is sometimes spoken of as
+_positive_ or _constructive eugenics_, the second as _negative_ or
+_restrictive eugenics_.
+
+=Constructive Eugenics Must Be Based on Education.--=As to the first
+phase, direct selection for superiority, the campaign must, in the very
+nature of things, be one of education. With the necessary knowledge of the
+facts in mind, the awakening conscience of the individual together with
+an enlightened public opinion will form the safest guide. Increasing
+popular comprehension of the inevitable nature of human inheritance must
+engender a sense of responsibility as to the positive eugenic fitness of a
+contemplated marriage. The growth of this sentiment will doubtless be
+slow, and properly so, for as yet we have but half-lights on what are the
+most desirable types of humanity. No one can say what the highest type of
+man should be, but almost any one can readily pick out types which
+certainly should _not_ be.
+
+=Inferior Increasing More Rapidly Than Superior Stocks.--=Modern
+eugenists, although realizing that the constructive phase is of great
+importance, are making no attempt to map out any fixed mode of procedure
+for it beyond pointing out the desirability of larger families among the
+better classes. The need for individuals of superior physical, mental and
+moral qualities to multiply is so obvious as scarcely to require comment.
+Yet the fact is that judging from all appearances these are the very ones
+who have the lowest birth-rate. Eugenics is mainly concerned with the
+relative rates of increase of the various classes, not with mere fertility
+in itself. And the actual increase must be measured in terms of the extent
+to which birth-rate exceeds death-rate. If a high birth-rate is
+accompanied by a high death-rate then it is not especially significant in
+increasing a given class as a whole. All available evidence points to the
+fact that to-day the lower strata of society are far outbreeding the
+middle and higher, with an almost negligible difference in death-rate, and
+just in the measure that these lower strata are innately inferior just in
+that degree must the race deteriorate. The seriousness of the whole
+situation as it exists to-day hinges, therefore, on the extent to which
+the lower strata are inferior to those above them.
+
+=An Unselected Population May Contain Much Valuable Material.--=In
+evaluating these lower strata a matter of very great importance is whether
+the population is a selected or an unselected one. If the population has
+been long resident in a given region and has had fairly good opportunity
+for education then we will find in the lower reaches a larger percentage
+of sedimentation made up of the worthless and inferior stocks. If,
+however, a continual fomentation and geographical shifting of the
+population is in progress as in parts of America, or if adequate
+educational opportunities are lacking, as in some parts of Russia, the
+poor and less well-to-do classes may contain, no one can tell how much,
+relatively valuable stock.
+
+Forel remarks on this point as follows:
+
+    "If we compare the nature of delinquents, abandoned children,
+    vagabonds, etc., in a country where little or nothing has been done
+    for the people (Russia, Galicia, Vienna, etc.), with that of the same
+    individuals in Switzerland, for example, where much has already been
+    done for the poor, we find this result: In Switzerland, these
+    individuals are nearly all tainted with alcoholism, or pathological
+    heredity; they consist of alcoholics, incorrigibles, and congenital
+    decadents, and education can do little for them because nearly all
+    those who have a better hereditary foundation have been able to earn
+    their living by honest work. In Russia, Galicia, and even in Vienna,
+    we are, on the contrary, astonished to see how many honest natures
+    there are among the disinherited when they are provided with work and
+    education."
+
+=The Lack of Criteria for Judging Fitness.--=Barring the untold hordes of
+actual defectives who have gravitated into this lower stratum, there are
+few positive criteria by which we can measure the real fitness of the
+remainder. Before we can set out on a campaign of positive eugenics we
+must have some standard by which to steer, and it would be a rash advocate
+indeed who would assert that class distinction alone, or even success as
+measured by public opinion to-day should be our whole criterion of
+fitness. Shall we measure fitness in terms of how successfully one can
+acquire worldly goods, or in other words, by the property test, or what
+shall be our standard?
+
+=The College Graduate.--=Many of our modern critiques of the birth-rate
+situation make much of the fact that our college graduates as a group are
+scarcely reproducing themselves. According to Davenport, Bryn Mawr College
+between 1888 and 1913 has graduated 1,193 bachelors of arts, but these
+women have produced up to January, 1913, only 263 girls to take their
+place in the next generation. He also points out that statistics on some
+of the graduate classes of Harvard of twenty years ago or earlier show
+that they are little more than maintaining themselves; thus one class of
+328 graduates twenty years later had produced 195 sons, and in another
+case a class of 278 individuals had produced, twenty-five years later, 141
+sons. Relatively similar statistics can be cited for other eastern
+colleges.
+
+All such cases of college graduates cited as especially deplorable
+declines in birth-rate are based on the assumption that these individuals
+are a particularly superior stock.[19] But one might question this premise
+as a generalization. It may or may not be true. Are they superior or have
+they had mainly a combination of luck and incentive, luck in that their
+parents had sufficient means, acquired possibly through their own
+superiority, possibly not, to send them to college, and incentive derived
+from a fortunate environment which awakened a desire in them--or in their
+parents for them--for college education? Is the woolly-witted son of
+opulence, so abundant in our colleges to-day, who is boosted through by
+hook or by crook, of superior eugenical value to the alert eager boy--and
+his name is legion--destined for economic reasons to go to work at or
+before the completion of his high-school course, perhaps because of the
+very fact of an unlimited fecundity in his own family which necessitates
+his help for the general support?
+
+When one first learns of the declining birth-rate among college women and
+men he feels appalled, but immediately the question flashes up, if this is
+_the_ superior stock, and up to date it has died out or is dying out
+rapidly, whence then this ever augmenting rush of young folk who fairly
+deluge our universities and colleges to-day? Does it not rather point to
+the fact that in our own country at least, the man who will and can take
+a college education successfully is not so much the product of breeding
+from college men, but of a prosperity which leaves a sufficient surplus in
+the family exchequer to enable sons and daughters to go to college, and is
+it not reasonable to suppose that there is yet an abundant stock back of
+these who similarly await but the golden touch of opportunity? When we
+consider such men as Carlyle, Lincoln and a host of others who were not
+the sons of collegians, although we may be university pedigreed ourselves
+we can not but feel doubtful of the validity of a premise which takes a
+college stock unqualifiedly as having any considerable monopoly of innate
+superiority. After all, college can mean little more than opportunity, and
+the obtaining of such opportunity in this world of economic maladjustments
+and accidents of social position is too largely a matter of chance, at
+least in America, to stamp the possessors of these advantages, on this
+criterion alone, as of inborn superiority. Undoubtedly much that is
+intrinsically good now slumbers in the lower strata of society because of
+lack of favorable environment to call forth the latent possibilities.
+
+=Native Ability, Independence and Energy Eugenically Desirable.--=Although
+we can not sift out with certainty the superior from the inferior in our
+normal population by the property test or the educational standard alone,
+it is undoubtedly true that, on the whole, native ability, independence
+and energy are present to a higher degree in our well-to-do and prosperous
+families than in the stocks which merely hold their own or which
+gradually decline, and there is no gainsaying the fact that in so far as
+the lower classes are where they are through actual deficiency--and there
+are enormous numbers in this category--they threaten our very existence as
+a race. It is imperative that the great middle class in particular
+establish in some way a selective birth-rate, by increased fertility on
+their own part, and diminished fecundity on the part of inferior stocks,
+which will offset or more than offset the disproportionate increase of the
+socially unfit.
+
+=Four Children to Each Marriage Required to Maintain a Stock.--=It is
+estimated that under present conditions an average of at least four
+children should be born to each marriage if a stock is to maintain its
+numbers undiminished. Some of our most valuable strains are falling far
+short of this average. In a statistical table on the relative fertility of
+different stocks, prepared by Pearson, we find the mentally defective,
+criminal, deaf-mute and degenerate stocks heading the list with averages
+ranging from five to seven children per family, while the American
+graduate (based on Harvard statistics) and the English intellectual types
+average less than two children per marriage. While the death-rate is
+higher in the undesirable classes mentioned, it is by no means enough
+higher to compensate for the difference in birth-rates. Thus while certain
+very desirable types are not maintaining themselves genetically, other
+extremely undesirable ones are rapidly more than replacing themselves.
+Investigations made by Heron in London show that this condition as regards
+English desirables did not exist sixty years ago; then the richer a
+community was in professional men and well-to-do families, the higher was
+the birth-rate.
+
+=Factors Contributing to Low Birth-Rate in Desirable Strains.--=Most
+students of the subject believe that the fecundity of much of the best
+blood in our country has reached such a low ebb as to threaten the whole
+fabric of our commonwealth. How to correct this is the pressing problem to
+which no one has found a solution. However much one may deplore it the
+fact remains that always in the history of the civilized world with the
+rise of material conditions in any class of a population there has come an
+accompanying limitation of child-birth. Explain this as we may in modern
+times--whether as an awakened individualism which looks only to the
+immediate interest of the individual as against the ultimate interest of
+the race, or a desire for luxuries or for a better opportunity for smaller
+numbers of children, or as a determined effort of the wage earner to
+better his conditions, or to the feminist movement with its accompaniment
+of a greater personal freedom of married women and the recognition of the
+fact that marriage and child-bearing are often bars to employment, or to
+general increasing pressure of economic burdens--in brief whatever the
+cause or causes, there is no denying the fact of a diminishing birth-rate
+among our abler men and women. Moreover, no amount of coaxing, cajoling or
+dire prophecy seems to avail in altering the conditions. Various partial
+remedies, many of them of questionable practicability, have been proposed,
+but so far there has been no far-reaching effort made to put any of them
+into effect. It has been suggested that society return to the simple life
+so that our young folk may marry earlier and live more easily on limited
+means, but so far few volunteers have appeared to lead the procession.
+While there is no doubt that present economic conditions tend to penalize
+parenthood, the simple life will not return for the mere asking. It has
+been pointed out that the father is in unfair competition with the
+bachelor and is also unfairly taxed in comparison, and some would
+therefore tax unmarried men more heavily. Others would pay a direct bounty
+on reproduction, but it is probable that such rewards would merely
+stimulate families of the lower types to increased fruitfulness. And so
+one panacea after another may be weighed and found wanting.
+
+=The Educated Public Must Be Made to Realize the Situation.--=It seems
+probable that the most success will be met with through the slow and
+unspectacular methods of education. The necessity of the situation must be
+driven home so that it becomes part and parcel of the collective
+intelligence of the educated public. Different ideals of life will have to
+be established in the young. If knowledge of the facts of heredity is
+thoroughly disseminated among the people and ideals regarding parenthood
+are fostered, then much will have been accomplished by the psychic power
+of suggestion alone toward the end desired.
+
+=Utilization of Family Pride as a Basis for Constructive Eugenics.--=There
+are few more powerful incentives to make the best of one's abilities, or
+few greater deterrents from vice than family pride; and there is no
+reason why this same sentiment may not be aroused in behalf of unborn
+generations. The sentiment of caste or aristocracy in some form is well
+nigh universal in mankind. The family of Mr. A came over in the Mayflower
+and is therefore worlds above the family of Mr. B, who arrived fifty years
+later. Mr. X's income is $5,000 a year, Mr. Y's only $1,500. The poor
+family in the front suite of the tenement regards itself as far superior
+to the one in the rear. Among criminals the professional house-breaker
+feels himself to be of higher caste than the sneak-thief, and in turn is
+surpassed by the bank-burglar. Even in the insane asylum the feeling is
+rampant. With such a wide-spread tendency for a foundation the creation of
+a sentiment of eugenic aristocracy is by no means a visionary undertaking.
+
+=The Tendency for Like to Marry Like.--=Even now there is a decided though
+unconscious tendency for like to marry like and thus create particular
+strains. We have lines, for instance, which produce notably families of
+scholars, others which yield mainly statesmen, and still other strains of
+inventors, of financiers, of naval men, of soldiers, and of actors
+respectively. And there is little doubt that people, with the facts of
+inheritance of ability once before them, will be led to act more or less
+in accordance with their knowledge. On the other hand, due apparently to
+the same unconscious tendency for like to marry like, we find produced
+criminalistic, feeble-minded, deaf-mute and tubercular stocks. The first
+type of family is often termed _aristogenic_ and the second or defective
+type, _cacogenic_.
+
+=Public Opinion as an Incentive to Action.--=Much of our social conduct is
+the result of the pressure of public opinion, yet so accustomed are we to
+this that we ordinarily do not feel it as a hardship. There is little
+doubt that similarly the more wholesome attitude toward parenthood
+advocated by the eugenist would be taken as a matter of course, once the
+idea became prevalent. It would come to be one of those socially
+preconceived ideas which are as much actualities and which become
+unconscious guides to action no less certainly than do the more obvious
+personal habits of the individual. And just in the degree that we as a
+race get the "feeling" that intellect, morals and skill are highly
+desirable attributes in marriage selection, just in that degree will one's
+affections in their earlier stages gravitate toward individuals who
+possess such qualities in high degree. In the main, those stocks which
+have shown by ancestral as well as personal achievement their superiority
+will tend to insure most certainly a continuation of this superiority in
+offspring.
+
+=Choosing a Marriage Mate Means Choosing a Parent.--=Although marriages,
+as all young folks know, are made in Heaven, it is interesting to see what
+a vast number of these foreordained matches coincide with propinquity in
+college, in church, or in the same social set. Moreover, children are born
+here on earth. The one thing of all things that the eugenist desires is
+for these young folk to get a clear-eyed vision of the fact that in
+choosing a marriage mate they are also choosing the future father or
+mother of their children with all that this implies.
+
+=The Best Eugenic Marriage Also a Love Match.--=A few recent writers, who
+show an utter misconception of what the aim of modern eugenics is, have
+raised the cry of give us the old-fashioned love match instead of the
+eugenic marriage, as if the eugenist's ideal of moral cleanliness, freedom
+from transmissible physical taints or mental enfeeblement, and an attitude
+of special approval toward marriages which bring together individuals of
+more than average mental or spiritual endowment, had anything in it that
+was inimical to love. No one better than he realizes the sordid depths to
+which marital relations devoid of mutual affection and regard must reach.
+Certainly there is nothing in the eugenic ideal when its full import is
+understood that can shock the sensibilities of the most delicate-minded.
+Indeed it is people of fine susceptibilities who will be the first to feel
+repugnance toward a marriage which means mental or physical deterioration
+of their own blood.
+
+=Good Traits No Less Than Bad Ones Inherited.--=An inspection of such
+charts as those shown in Figs. 37, 38 and 39, pp. 313, 314, 316--and an
+abundance of such encouraging records may now be found--reassures us in
+our convictions that good traits are no less inheritable than bad ones.
+And what any healthy, mentally well-endowed person may be depriving the
+world of if he or she declines to enter into a fruitful marriage can not
+be better exemplified than in the following excerpt from Davenport:
+
+    "Many a man at the opening of his life work vows, as Judge John Lowell
+    of the middle of the eighteenth century did, as he was being graduated
+    from Harvard College, that he will never marry. But nature was too
+    strong for John Lowell and he married three times, and among his
+    descendants was the director of a great astronomical observatory, the
+    president of Harvard College, a principal founder and promoter of the
+    Massachusetts General Hospital and the Boston Atheneum; the founder of
+    the city of Lowell and its cotton mills; the founder of the Lowell
+    Institute at Boston; the beloved General Charles Russell Lowell and
+    his brother, James, both of whom fell in the Civil War, and James
+    Russell Lowell, poet, professor and ambassador; besides brilliant
+    lawyers and men entrusted with large interests as executors of
+    estates. Do you think John Lowell would have taken that vow could he
+    have foreseen the future?"
+
+
+[Illustration: FIG. 37
+
+Pedigree of family with artistic (dark upper section), literary (dark
+right section) and musical (dark left section) ability (from Davenport).]
+
+
+=The Elimination of the Grossly Unfit Urgent.--=But even if, under present
+conditions of partial knowledge and lack of an adequate standard, the
+constructive phase of eugenics must be left in the main to the awakening
+conscience of the individual as humanity improves in general
+enlightenment, the second phase, the elimination of the grossly unfit is
+one of the greatest social obligations that confronts us to-day. For if
+there is an alarming amount of mental impairment in civilized nations, and
+if the problems of pauperism, inebriety, prostitution and criminality are
+closely interwoven with the problems of mental unsoundness, as we have
+every reason to believe from available data, then any means which will
+operate toward securing normally functioning brains will at the same time
+operate toward diminishing, defects and delinquencies. And inasmuch as a
+considerable proportion of defects, both mental and physical, are
+inheritable, it is obvious that if we can diminish the number of children
+born into the world with defective brains or bodies we have made a long
+stride in the right direction.
+
+
+[Illustration: FIG. 38
+
+Inheritance of ability (from Kellicott after Whetham).]
+
+
+=Suggested Remedies.--=But how go about it? Various schemes have been
+proposed, of which the chief are as follows:
+
+    1. Laws restricting marriage.
+
+    2. Systems of mating with the purpose of covering up and gradually
+    diluting out defective traits.
+
+    3. Segregation during the reproductive period.
+
+    4. Sterilization.
+
+    5. Education in the principles of eugenics.
+
+=Inefficacy of Laws Which Forbid Marriage of Mental Defectives.--=The
+utter inefficacy of the first proposition, namely the enactment of laws
+restricting marriage, at least as regards the socially unfit whose
+condition is based on impaired mentality, has been demonstrated time and
+again. If they are forbidden marriage, they merely have children without
+getting married. Most states have laws to prevent the marriage of such
+individuals but these laws are almost wholly ineffective in preventing
+procreation on their part. We might as well recognize once for all that in
+such cases nothing short of close custodial care or sterilization will
+accomplish the end desired.
+
+As to the second proposition, systems of mating with the purpose of
+covering up and gradually diluting out defective traits, this has been
+shown to be possible with certain types of defectives. Whether it is
+desirable or not is a different question.
+
+
+[Illustration: FIG. 39
+
+Inheritance of ability (chart condensed and incomplete) in three markedly
+able families (from Kellicott after Whetham):
+
+1, Charles Darwin; 2, his cousin, Francis Galton, founder of the modern
+eugenic movement.]
+
+
+=Systems of Mating Impracticable in the Main.--=By systems of mating, it
+should be said, is not meant the arbitrary marrying of two individuals
+willy-nilly, but rather it is the prevention from marriage of two
+individuals having similar defects. In general the facts at our command
+indicate that in the majority of cases the offspring from a marriage of an
+insane, feeble-minded or epileptic person with a normal individual free
+from all neuropathic taints are normal or at most show but slight effects
+of the taint. But what normal individual would knowingly marry into such a
+stock? With few exceptions such traits where inheritable are apparently
+negative, that is, not represented by some positive abnormal factor but
+due to the lack of some element or elements necessary to the proper
+working of the normal brain. In the offspring of such a union the
+necessary missing factors are supplied by the normal parent. Or in
+Mendelian phraseology, the defective traits are recessive and are
+dominated by the normality of the other parent. Such offspring, however,
+while apparently normal of body are not normal of germ-plasm, inasmuch as
+half of their germ-cells will carry the abnormality of the defective
+parent as earlier explained (page 119) under Mendelism. We have already
+seen (page 119) how by continually marrying into strong strains the
+liability to recessive defect can be diluted out until the descendants are
+no more likely to have defective children than are members of our ordinary
+population. If, however, as is estimated in Bulletin No. 5 of the
+_Eugenics Record Office_, about thirty per cent. of our general population
+already carry recessive neuropathic taints, it certainly is a hazardous
+proceeding to attempt thus to breed out nervous defects unless one is
+absolutely sure of the normality of the strain into which it is proposed
+to marry. The great difficulty is in determining whether or not there is a
+defective ancestry in a given stock. We have at present no criteria for
+identifying normal individuals who have defective germ-plasm. As a
+practical test, however, if no defect has appeared in the stock for three
+or four generations back, the marriage would be relatively as safe as are
+the marriages of our average population to-day.
+
+=Corrective Mating Presupposes Knowledge of Eugenics.--=But such a scheme
+of corrective mating presupposes a relatively high degree of intelligence
+and judgment on the part of the participants, and this is just what we do
+not have and in the nature of things can not get, in the types of
+feeble-minded, epileptic and degenerate strains we are striving to
+eliminate. All our evidence shows that when unrestricted there is a marked
+tendency for feeble-minded to mate with feeble-minded, degenerate with
+degenerate. About sixteen per cent. of the feeble-minded, in fact, come
+from consanguineous marriages. If we try to legislate them into specific
+types of marriage then we encounter the same futility pointed out under
+our discussion of restrictive legislation, they will produce offspring
+without the formality of marriage.
+
+In certain cases of insanity and in other than neuropathic defects one can
+see how the system might be inaugurated with greater prospects of success,
+but even then a knowledge of the principles of eugenics would be necessary
+to the participants, or in other words we could only accomplish our end
+through our fifth proposition, education.
+
+=Segregation Has Many Advocates.--=As to the third proposition,
+segregation during the reproductive period, this seems to have a larger
+number of advocates than any other coercive measure. While on theoretical
+grounds it is plausible enough, when we face the actual putting of the
+method into practise we are confronted by the fact that tremendous sums of
+money would be required to sequestrate and maintain colonies or industrial
+refuges.
+
+When one realizes that no state now provides for more than a small
+minority of its defectives, and knowing also of the pressure that must be
+brought to bear on legislatures to secure sufficient funds to provide for
+these cases of extremest urgency, one can not be overly optimistic about
+the practicability of extensive sequestration.
+
+E. R. Johnstone, the superintendent of a large training school for
+feeble-minded in New Jersey, points out that no state in the Union is
+providing for many more than one-tenth of her feeble-minded and
+epileptics. If his estimate is true, to place in institutions, treat and
+train all its feeble-minded and epileptics would even now almost swamp any
+state treasury. But what _will_ it be in the future if we permit this
+unrestricted nine-tenths to go on and multiply their kind?
+
+Leaving out of account the enormous sums spent in private charities even
+now from one-fifth to one-seventh the total public expenditures of almost
+any one of our states is going to maintain its defectives, dependents and
+criminals. From the 1912 report of the secretary of state, in the state of
+Wisconsin, for instance, I learn that of the total expenses for 1912,
+sixteen per cent. was for charitable and penal institutions. The situation
+is even worse in some other states. Think of it! Think what a large total
+of expense it becomes! And the expense is far secondary from the
+humanitarian standpoint to the misery involved.
+
+In the _Survey_ of May 24, 1913, we find Mr. Hastings H. Hart, Director of
+the Department of Child Helping of the Russell Sage Foundation, proposing
+very specifically "a working program for the extinction of the defective
+delinquent," which involves segregation during the reproductive period. He
+gives the number of feeble-minded under public care as 20,000 in
+institutions for the feeble-minded, 16,000 in almshouses, 5,000 in
+hospitals for the insane, and 26,000 in prisons and reformatories, or a
+total of 67,000 already under custodial care. And he asserts that as
+nearly as can be judged, this is one-third of the feeble-minded persons in
+the United States.
+
+Between this estimate that one-third of our feeble-minded are in
+institutions and Doctor Johnstone's that we are not providing for many
+more than one-tenth of our feeble-minded and epileptic, there is a wide
+discrepancy, but I know of no accurate data[20] whereby the matter can be
+settled definitely. One point of difference may be that Doctor Johnstone
+specifically includes epileptics and another may be one of definition of
+feeble-minded. However, supposing that we could get them all into
+institutions, institutional care at present by no means also implies
+prevention of propagation. It is not an unusual history of feeble-minded
+women in our county poor-houses that they alternate between periods of
+housework in some family and periods of residence in the almshouse, the
+return to the latter being only too often to bear an additional child.
+
+Not a few students of the problem, however, advocate a rigid segregation
+as the only reasonable preventive measure, no matter what the expense.
+They point out that the cost is mounting up higher each year and that we
+are only increasing it ultimately by procrastination. They urge, moreover,
+that when counting the cost of the segregation of the feeble-minded we
+should bear in mind also that we are reducing the expenses of our other
+charity and penal institutions, since much of degeneracy, pauperism and
+petty criminality centers in mental enfeeblement. Some believe that
+colonies can be established which are in considerable measure
+self-supporting. Doctor Johnstone, for instance, although his estimates of
+the number of feeble-minded and epileptic is one of the highest, sketches
+out in a recent paper (in _Pediatrics_, August, 1912) a plan which he
+considers feasible.
+
+But what assurance have we that we can prevent the production of
+defectives by segregation? In reply may be cited a recent experiment on an
+extensive scale. Cretinism is a condition due to disease of the thyroid
+glands. It is characterized by goiter, marked deformities and imbecility.
+It is hereditary and has been very prevalent in certain valleys of
+southern Switzerland and northern Italy. Cretin mated with cretin and
+consequently a large new supply was constantly produced. In recent years
+in certain communities the sexes have been segregated (see _Eugenic
+Review_, 1910, Jordan) with the result that in such places cretinism has
+about disappeared.
+
+Coming now to the fourth solution proposed, namely, sterilization,[21] let
+us consider some of its alleged advantages and disadvantages.
+
+=Sterilization.--=First of all, since there is some considerable popular
+misunderstanding on the subject, it should be made plain that by
+sterilization is not necessarily, nor in fact generally, meant
+asexualization, or the removal of the reproductive glands. On the
+contrary, in the male, sterilization is ordinarily accomplished by an
+operation known as _vasectomy_, in which a small piece of each sperm duct
+is removed. Such reports on it as I have found indicate that it is a
+comparatively simple minor operation which involves no special
+inconvenience or hardship on the subject beyond the deprivation of
+offspring. In fact, according to Doctor Sharp's report, in the majority of
+cases where it has been put into practise the patient has usually
+submitted voluntarily after having the details of the situation explained
+to him and has often advised fellow delinquents to do likewise.
+
+Even should later developments show that a mistake had been made, in all
+probability the matter could be remedied by a second operation in which
+the cut ends of the ducts can be reunited. This has been accomplished
+experimentally in dogs, and furthermore, in men rendered sterile by
+occlusion of the duct through inflammatory diseases, the sterility has
+been remedied by removing the blocked area and reuniting the ends of the
+duct on either side.
+
+In women the corresponding operation--a section of the oviduct--is termed
+_salpingectomy_. Here, however, the operation is a more serious one as it
+usually involves opening the abdominal cavity and the accompanying hazard
+of infection, a danger sufficiently great that it is safe to say that the
+operation will be resorted to more rarely than vasectomy in man.
+
+=As a Eugenic Measure.--=Sterilization as a eugenic measure has many
+advocates and perhaps more opponents; and among the latter, it must be
+said, are many competent and thoughtful students of the subject who
+recognize existing conditions and deplore their continuance as much as any
+one. They maintain that while we may have to come to it as a last resort,
+we are yet too ignorant of the actual effects of the operation, or are too
+little informed on the inheritability of the specific traits we are trying
+to eradicate, to launch forth on so radical a program. We must not forget
+that when we put sterilization into effect we are going to have to deal
+with individual cases, not general averages.
+
+=To What Conditions Applicable.--=And just here, it seems to me, is the
+crux of the situation. When confronted by the defective individual, in a
+practical case, just what criteria are we going to use to determine
+whether this particular individual should be sterilized or not? Nearly all
+of the twelve states which have sterilization laws specify insanity,
+feeble-mindedness, epilepsy and criminality.
+
+=In Insanity.--=When it comes to insanity I strongly suspect that those
+who have the selection of the examining board will have difficulty in
+finding an alienist who is willing to take the responsibility of deciding
+on just which insane individuals shall be operated on and which not. For
+among the insane there are so many kinds and degrees of mental
+unsoundness, and these are of such varying and as yet unknown eugenical
+significance, that a positive decision is frequently out of the question.
+Of the twenty-seven or more recognized forms of insanity who knows with
+any considerable degree of certainty which are heritable, which not? Shall
+we treat all manic-depressives alike? Shall we treat them as, for
+instance, we would those suffering from dementia precox? Who will take the
+responsibility of answering positively? Again, what shall we do in cases
+of paresis, or general paralysis of the insane, an affliction which
+probably invariably has syphilis as its antecedent? Yet it constitutes one
+of the commonest forms of insanity found in asylums. Doctor George H.
+Kirby, director of Clinical Psychiatry, Manhattan State Hospital, says
+that with one exception there are more admissions of paretics to Manhattan
+State Hospital than sufferers from any other form of mental disorder. He
+continues, "We find that when either the father or the mother suffers from
+paresis that many other members of the family may be infected with
+syphilis, and furthermore, we find that a surprisingly large number of
+children in these families are feeble-minded, nervous, or in other ways
+abnormal." But here, it is clear, the patient has done the damage before
+he reached the hospital, nor was it paresis as such that did the harm but
+the syphilitic infection of which paresis itself was but the outcome.
+
+Certainly the one fact which stands out conspicuously when we face most
+concrete cases, is that at present we need more urgently than
+sterilization laws for the insane, exhaustive studies of the
+inheritability of specific mental infirmities that we may know with some
+degree of certainty which warrant sterilization.
+
+Yet on the other hand one of the most disquieting facts that confronts us
+to-day is the large number of patients who are on parole from our
+hospitals for the insane, subject to recall. What shall we do with them?
+Shall we submit them to the tremendous hardship of still remaining under
+custodial care although to all intents and purposes sane, or shall we make
+their release contingent upon their submission to vasectomy or
+salpingectomy?
+
+In a few cases such as Huntington's chorea (Figs. 26, 27, pp. 114, 115) we
+can proceed with a fair degree of assurance, for we know that this
+dreadful malady is transmitted as a positive trait and that in all
+probability half of the children of an afflicted individual will inherit
+the defect. Such patients, if they ever rally sufficiently temporarily to
+leave the hospital, or where encountered outside the hospital should
+certainly be restrained from procreation. It is questionable if even their
+children, though apparently normal, should be allowed to have offspring,
+for usually the disorder does not manifest itself until middle life and
+then it is too late to try to prevent its transmission since the affected
+individual has already probably married and had children. But Huntington's
+chorea is a comparatively rare form of insanity, and one of only a few
+about which our knowledge as regards its transmissibility is fairly
+satisfactory.
+
+=In Feeble-Mindedness.--=When we come to institutions for the
+feeble-minded, however, there seems to be much more unanimity of opinion
+among physicians in charge of such institutions that sterilization would
+be an effective and satisfactory disposition to make of many cases, if we
+are to release the patients in question from custody. Unquestionably in
+cases of imbecility it is easier than in insanities to pass conclusive
+judgment on the inheritability of the condition in a large class of cases.
+Practically all are agreed that either permanent custodial care through
+the reproductive period or sterilization should be enforced. Some maintain
+that such individuals should remain permanently in institutions anyway and
+that therefore to sterilize them is needless, while others urge that if
+sterilized many capable of making their own living could be freed and
+allowed to do so.
+
+According to Goddard the feeble-minded woman is about three times as
+likely to find a mate as a feeble-minded man, hence it would seem to be of
+much greater importance to sterilize the woman than the man.
+
+Again it might be urged with much justification, that even though
+sterilized, the feeble-minded individual because of lack of self-control
+will transgress sexually and will thus certainly become a menace to
+society in the spread of venereal diseases. If Mr. Hart's estimate is
+anywhere near correct, that there are 60,000 feeble-minded women in the
+United States of child-bearing age, and that 13,000 are already in
+custody, then the task of getting all women of this class into custody is
+not so insurmountable as would at first appear.
+
+=In Cases of Epilepsy.--=As to epilepsy, I find a very decided difference
+of opinion among physicians. Some consider it, on account of its
+apparently strong inheritability, together with the shocking crimes
+perpetrated by epileptic criminal types, one of the most serious menaces,
+while others point out that we know nothing of the real cause of epilepsy,
+that there are all degrees and shades, that it is probably referable to
+different causes in different cases and that no one is able to say what
+the offspring of any given epileptic will be.
+
+As to criminal types, here again we face the difficulty of deciding any
+particular case. Let us suppose that twenty-five per cent. of criminals
+are mental defectives, how shall we sift them out from the seventy-five
+per cent. who are supposed to be eugenically normal? Doubtless in many of
+the twenty-five per cent. class, the indications of defective mentality
+are sufficiently evident to prevent mistakes, but a considerable number of
+uncertain status must also remain near the border-line.
+
+=Sterilization Laws.--=Although twelve of our states already have
+sterilization laws, only two, Indiana and California, seem to have made
+any active attempt to enforce them. The situation is too new yet in
+Wisconsin, Michigan and Pennsylvania for these states to have shown what
+they intend to do. Although the Indiana law says, "it shall be compulsory
+for each and every institution" to maintain the practise, it has fallen
+into disuse since 1911, presumably because the governor believed the law
+unconstitutional. It is of interest to see the motive underlying the law
+in various states. In the majority it is purely eugenic. In Connecticut it
+is mainly eugenic though partly therapeutic. In California it is
+apparently in part therapeutic, since it is stated as being for the
+physical, mental or moral benefit of inmates of various state
+institutions, and in part punitive and eugenic, since individuals twice
+committed for sexual offenses or three times for other crimes are subject
+to the operation.
+
+In Washington and Nevada the object is purely punitive, the persons
+specified being habitual criminals and persons adjudged guilty of carnal
+abuse of female persons under ten years of age, or of rape. In these
+states also the court orders the operation instead of leaving it to the
+decision of a board of medical experts.
+
+=Social Dangers in Vasectomy.--=It has been urged against vasectomy that
+it will work untold harm because it relieves of the responsibility of a
+probable parentage. This argument does not appeal to one as very weighty
+as far as the imbecile or other degenerate is concerned, because one of
+the very traits characteristic of such individuals is lack of any sense of
+responsibility. By this same token, however, we have a very good argument
+for sequestration as against sterilization, for the degenerate, even
+though sterilized, will not be restrained sexually and will be likely to
+disseminate venereal diseases or commit rape. Furthermore, there will be
+the temptation to sterilize and liberate certain types that would
+otherwise have been kept permanently in custody.
+
+=Our Present Knowledge Insufficient.--=When all is said and done, after we
+take into account the meagerness of our present knowledge on the subject,
+it is not to be wondered at that many thoughtful students of a
+conservative turn of mind, feel that any considerable practise of
+sterilization is premature. The problem has so many phases, and despite
+occasional bits of positive knowledge, we are yet in such a sea of
+ignorance regarding it, that in no field is the good Friar Laurence's
+admonition of "wisely and slow; they stumble that run fast," needed more
+at present than it is here.
+
+There is little doubt that in theory the feeble-minded and similar
+defectives should be sent to institutions and kept there, but the
+important practical question is, can this be done? We can have no final
+answer until it is tried. While the initial expense would undoubtedly be
+great, if we could keep our defectives from propagation for a single
+generation we could very materially lessen their numbers and in succeeding
+generations the expenses of their care would rapidly diminish.
+
+The one crying need that stands out most prominently in this whole field
+is that of careful investigation of individual cases and specific types of
+malady, together with an accurate census of conditions as a whole. Our
+knowledge of individual malign heredities is too meager to carry us very
+far at present. When we have found after adequate investigation in just
+which specific types of defects heredity is an important factor--and we
+shall undoubtedly find it to be one in many cases--then we can proceed
+confidently with sterilization, if it will prove to be more practical and
+desirable than sequestration.
+
+=Sterilization Laws on Trial.--=It will be of great interest and
+instruction to see how extensively, in the various states which have
+recently passed sterilization laws, the experts selected will find it
+expedient to carry on sterilization, and what criteria they will use in
+deciding on individual cases. That sterilization can be put into effect is
+indisputable, as may be seen from the fact that several hundred operations
+have been performed in Indiana. If the board on whom the decision depends
+happens to be one which feels that many people are likely to distress
+themselves unduly over the border-line cases, and overlook the fact that
+there is always a goodly residue with which to proceed without great risk
+of mistake, then we may expect to see a vigorous campaign inaugurated, and
+those of us who are still undecided in the matter will have an opportunity
+of learning more certainly the merits or the failings of the scheme.
+
+Certain married degenerate types would seem to be the ones most urgently
+demanding attention. Having already begotten several defective children
+and with nothing else in prospect but the production of the same kind, it
+is difficult to see from any standpoint why a vasectomy on the male would
+not be a merciful act. There are not a few such families where the father
+is periodically in the hands of the law and yet not in permanent
+restraint. Once in custody his release could be made contingent on
+vasectomy.
+
+=An Educated Public Sentiment the Most Valuable Eugenic Agent.--=Coming
+now to the last proposition, education of the public in the principles of
+eugenics, this is the method calculated to be of more far-reaching service
+than any other, in the negative as well as in the positive phases of
+eugenics. Education is necessary before we can have effective restrictive
+measures for the mentally incompetent established and enforced, and it is
+also a prerequisite to intelligent procedure on the part of normal
+individuals in considering their own fitness for marriage.
+
+Of greatest importance in preventing undesirable marriages, as far as
+people of normal intelligence is concerned, will be the sentiment of
+disapproval which will arise on the part of society itself when it becomes
+really convinced that certain marriages are inimical to social welfare.
+Public opinion is, in fact, one of the most potent influences in marital
+affairs, simply because refusal to abide by the dictates of the community
+means social ostracism.
+
+That social disapproval of certain unions can become a very real factor in
+preventing such marriage is evinced on all sides by the numerous barriers
+to marriage already in existence based on race, religious sect or social
+status. Even in our much vaunted democracies one is looked down on who
+marries "beneath" his or her social set. This sentiment of taboo, so
+readily and often so senselessly cultivated in our present human society,
+will inevitably spring up in consequence of a wide-spread knowledge of the
+facts of human heredity. It is to such a growth, to the establishment of a
+disapproval which is the product of its own sentiments rather than to
+legislative enactments, that society must look for the greatest
+furtherance of the eugenic program.
+
+Necessary as legal restraint is in certain cases, it must obviously be
+restricted to only the most glaring defects. Moreover, legislation can not
+run far in advance of public opinion.
+
+=The Question of Personal Liberty.--=It must be admitted that there is a
+reluctance on the part of many even thoughtful individuals to the
+application of methods which savor in any way of restraint. An objection
+not infrequently urged by such persons against the application of certain
+eugenic principles is that they demand an unwarranted curtailment of
+personal liberty.
+
+To those who hoist the flag of personal liberty, it may fairly be asked,
+how much personal liberty does the syphilitic accord his doomed and
+suffering wife and children, or how much personal liberty is the portion
+of the offspring of feeble-minded parents? Or, what quota of personal
+liberty will accrue to the ill-fated descendants of the epileptic, the
+habitual drunkard or criminal, the gross moral pervert, the congenially
+deaf and dumb, or to even the progeny which may result from the union of
+two well-established tubercular strains?
+
+We do not hesitate to send the pick of our stalwart healthy manhood to war
+to be slaughtered by the thousands and tens of thousands when an affront
+is offered to an abstraction which we term our national honor, and,
+sublimely unconscious of the irony of it all, we throw ourselves into a
+well-nigh hysterical frenzy of protest when it is proposed to stop the
+breeding of defectives by infringing to a certain extent on their personal
+liberties.
+
+Society has already found it necessary to suppress certain individuals
+and yet we hear little complaint about loss of personal liberty in such
+cases. But if it is necessary to restrain the man who would steal a purse
+or a horse, is it not still more urgent to restrain one who would poison
+the blood of a whole family or even of an entire stock for generations?
+Surely there can be but one answer; society owes it to itself as a matter
+of self-preservation to enforce the restraint of persons infected with
+certain types of disease and of individuals possessing highly undesirable
+inheritable traits, so that perpetuation of such defects is impossible.
+
+=Education of Women in Eugenics Needed.--=One of the most crying needs of
+the present is the awakening and educating of women to the significance of
+the known facts. For they are perhaps the greatest sufferers, and once
+informed, as a mere matter of safety if for no other reason, they will see
+the necessity of demanding a clean bill of health on the part of their
+prospective mates. Furthermore in the last analysis woman is the decisive
+factor in race betterment, for it is she who says the final yea or nay
+which decides marriage and thus determines in large measure the qualities
+which will be possessed by her children. Above all, young women must come
+to realize that the fast or dissipated young man, no matter how
+interestingly or romantically he may be depicted by the writer of fiction,
+is in reality unsound physically, and is an actual and serious danger to
+his future wife and children.
+
+=Much Yet to Be Done.--=But plain as is our duty regarding the application
+of facts already known, when we consider that the student of heredity has
+made only a beginning, it is equally evident that he must be urged on in
+his quest for new facts, and the establishment of new principles. There is
+imperative need to carry on proper experiments with plants and animals, to
+collect necessary data regarding man, and for what is scarcely less
+important, the publication of the facts already acquired so that the
+public may be guided aright.
+
+Just at present it is of the utmost importance to secure more trustworthy
+statistics in order that we may intelligently go about instituting
+suitable restrictive measures for undesirable human strains. We must know
+the exact number and kinds of feeble-minded, epileptic and insane in our
+population, and we must have more insight into the personal status and
+pedigrees of our delinquents and criminals. For purposes of rational
+procedure such information is indispensable. Much can be done by
+hospitals, "homes" and penal institutions by determining and recording
+more accurately all obtainable facts regarding the ancestry of their
+charges. Moreover, in such states as Wisconsin, where the state hospitals
+for the insane have each an "after-care-agent," the duties of such
+officers might well include the collection of more adequate data regarding
+the hereditary aspects of their patient's condition. And lastly, if in
+every census, whether state or national, it were made an important part of
+the work to secure accurate vital statistics, particularly as they pertain
+to human heredity, the contribution toward enabling us ultimately to
+purge the blood of our nation of certain forms of suffering, degeneracy
+and crime would be inestimably great.
+
+=A Working Program.--=And now after reviewing at some length various
+aspects of man's hereditary and congenital endowment, the important
+question arises as to whether it is possible, with the knowledge at
+present available, to go ahead with a practical program which will insure
+to the child of the future its right of rights, that of _being well-born_.
+When one considers the matter it is evident that much can be done at once.
+Most of the needs set forth in the preceding paragraph can clearly be met
+in a fair degree by instituting the procedures indicated.
+
+One of the obvious duties in a restrictive way that confronts us right at
+the start is the care and control of the feeble-minded and of the
+defective delinquent in such a way as to prevent procreation. Much help
+can be given also through intelligent agitation for the establishment of
+colonies for epileptics and the higher grades of feeble-minded which can
+be made in considerable measure self-supporting. A given colony must, of
+course, be for one sex alone. Much can be done, furthermore, by putting
+into operation, both in and out of institutions, effective systems of
+registering births and deaths together with accompanying facts which may
+prove of eugenical significance.
+
+Again, we should more surely identify and exclude undesirable immigrants
+and also undertake thoroughgoing investigations to determine which races
+we can not profitably assimilate into our own blood.
+
+Physicians should pay more attention to the hereditary and congenital
+aspects of their cases and make it more a matter of conscience than they
+do at present to advise patients with regard to marriage. Prenuptial
+medical inspection should become the custom, if not by law at least as a
+voluntary procedure. Every parent must come to realize the grave risk to
+which he is subjecting his daughter if a guarantee of physical fitness,
+even more than assurance of financial standing or social position, is not
+forthcoming from her prospective mate.
+
+Wholly apart from the field of heredity though in a realm intimately
+concerned with the birthright of the child, much practical good can be
+accomplished by pondering the facts and the fictions of prenatal influence
+and in the light of the knowledge thus gained, seeing that while foolish
+and unnecessary worries are abolished, the conditions of health, nutrition
+and occupation surrounding the expectant mother are the best obtainable.
+It is the sacred duty of every individual, moreover, to see that the
+maximal possibilities of his own germ-plasm are not lowered by vicious or
+unwholesome living.
+
+As individuals we can cultivate a greater sense of responsibility
+regarding marriage and parenthood in those for whose training we are
+responsible. We can study this whole subject conscientiously, keep pace
+with new knowledge and see that other people are likewise informed. In
+showing an enlightened interest in the ideals of eugenics and a
+sympathetic approval of wholesome marriages, a sentiment toward parenthood
+will gradually arise which will make it seem more desirable to many worthy
+people than it does at present. If we are of good stock ourselves we
+should recognize that it is highly desirable that we give to the race at
+least four children. On the other hand, if we come from a strain which is
+eugenically undesirable we should with equal conscientiousness refrain
+from contributing to human misery. For where serious obstacles to a union
+exist, renunciation is certainly a higher manifestation of love than is
+consummation of a marriage which will result in untold misery to the
+object of the affections. As a matter of fact, with adequate preliminary
+knowledge as to what actually constitutes a serious drawback to marriage,
+where such really exists and is recognized by the associated individuals,
+love of the kind that leads to marriage is not likely to arise.
+
+As has been suggested by various students of eugenics, it is even at
+present perhaps not infeasible for earnest individuals to start in a quiet
+way local centers for the keeping and filing of accurate records of their
+family traits for the future use of their descendants. Such groups,
+voluntary though they be, would soon acquire a degree of distinction that
+would make other people of good endowments wish to join in and go on
+record as eugenically desirable.
+
+Lastly, it should not be forgotten that good traits are inherited as
+certainly as bad ones. Moreover, in the realm of human conduct, even
+though the fundamental features of behavior are based on an inherited
+organization, man is not always driven by an inexorable linkage of
+inherited neutral units into only one line of conduct, since more or less
+capacity for alternative action is also inherited. It is the personal
+duty of every member of society to aid in affording the opportunity and
+providing the proper stimuli to insure that out of the many possibilities
+of behavior which exist in the young at birth, those forms are realized
+which are best worth while to the individual and to society. And while we
+recognize that improved environment alone can not correct human
+deficiencies we must nevertheless not relax our efforts to get cleaner
+foods, cleaner surroundings, cleaner politics and cleaner hearts.
+
+Why go on alleviating various kinds of misery that might equally well be
+prevented? When one squarely faces the issue, surely the absurdity of our
+present practises can not but be evident to even the most thoughtless.
+
+=Which Shall It Be?--=As a matter of social evolution, human homes
+originated in the necessity of an abiding place for the nurture and
+training of the young past their first period of helplessness. Well in the
+foreground of the mental picture which arises when we hear the very word
+_home_, are children. What shall the home of the future be with regard to
+its most important assets, the children? Shall we as a people continue to
+be confronted at every turn by the dull countenance of the imbecile, the
+inevitable product of a bad parental mating; or the feeble body and the
+clouded intellect of the child sprung from a parentage of polluted blood;
+or the furtive cunning of the born criminal, the will-less mind of the
+bred degenerate, or the shiftless spawn of the pauper? Or shall it be a
+type with laughing face, with bounding muscles, with unclouded brain,
+overflowing with health and happiness--in short, _the well-born child_?
+
+The answer is in our own hands. The fate of many future generations is
+ours to determine and we are false to our trusteeship if we evade the
+responsibility clearly laid before us. How conscientiously we heed known
+facts, how actively we acquaint ourselves with new facts, and how
+effectively we execute the obvious duties demanded by these facts, will
+give us the answer.
+
+
+THE END
+
+
+
+
+GLOSSARY
+
+
+ACQUIRED CHARACTERS, traits developed in the body through changes in
+environment or function, in contra-distinction to those which have their
+specific causes in the germ-cells.
+
+ADAPTATION (L. _ad_, to; _aptus_, fit), fitness to environment.
+
+ALBINISM (L. _albus_, white), a condition of deficiency in pigment.
+
+ALLELOMORPH (Gr. _allelon_, of one another; _morphe_, form), one of a pair
+of alternate Mendelian characters.
+
+AMEBA (Gr. _amoibe_, change), a primitive single-celled animal.
+
+AMPHIBIAN (Gr. _amphi_, both; _bios_, life), capable of living both on
+land and in water.
+
+ANTHROPOID (Gr. _anthropos_, man; _eidos_, form), man-like.
+
+ARISTOGENIC (Gr. _aristos_, best; _genesis_, origin), pertaining to the
+genetically most desirable human strains.
+
+ASSOCIATION AREAS, those regions of the brain in which presumably the
+higher mental processes are effected.
+
+ATAVISM (L. _ad_, before; _avus_, grandfather), a return in one or more
+characters to an ancestral type. See p. 8 for restricted modern usage.
+
+ATROPHY (Gr. _a_, negative; _trophe_, nourishment), a wasting away of a
+part of a living organism.
+
+AXON (Gr. _axon_, axis), the process from a nerve cell which becomes a
+nerve fiber.
+
+BINET-SIMON SCALE, a series of tests graded to age and previous training
+of the average normal child, much used in measuring mental deficiency.
+
+BIOLOGY (Gr. _bios_, life; _logos_, discourse), the study of life and of
+living things.
+
+BIOMETRY (Gr. _bios_, life; _metron_, measure), the study of biological
+problems by means of statistical methods.
+
+BLASTOMERE (Gr. _blastos_, germ; _meros_, part), one of the early cells
+formed by the division of the ovum.
+
+BLASTOPHTHORIA (Gr. _blastos_, germ; _phtheiro_, destroy), deterioration
+of the germ as the result of direct pathogenic or other disturbing agents.
+
+BLENDING INHERITANCE, inheritance in which the characters of the parents
+seem to blend in the offspring.
+
+CACOGENIC (Gr. _kakos_, bad; _genesis_, origin), pertaining to genetically
+undesirable human strains.
+
+CELL, the fundamental unit of structure in plants and animals.
+
+CENTROSOME (Gr. _kentron_, center; _soma_, body), a small body which
+functions in indirect cell-division.
+
+CHARACTER, any distinguishing feature, trait or property of an organism.
+
+CHEMOTROPISM (chemical and tropism), defined, p. 198.
+
+CHROMATIN (Gr. _chroma_, color), deeply staining substance of the
+cell-nucleus.
+
+CHROMOSOMES (Gr. _chroma_, color; _soma_, body), characteristic deeply
+staining bodies, typically constant in number and appearance in each
+species of animal or plant, which appear in the cell during indirect
+division.
+
+CHROMOTROPISM (Gr. _chroma_, color; _trope_, turning), defined, p. 198.
+
+CLEAVAGE, the division of the egg-cell into many cells.
+
+CONGENITAL (L. _con_, together; _gigno_, bear), present at birth.
+
+CONJUGATION (L. _con_, together; _jugum_, yolk), the union of germ-cells
+or unicellular individuals for reproduction.
+
+CONSTRUCTIVE (or positive) EUGENICS, a system of securing a superior race
+through propagation of the fittest individuals.
+
+CORTEX (L. _cortex_, bark), the outer or investing layer of the brain.
+
+CYTOPLASM (Gr. _kytos_, cell; _plasso_, form), the protoplasm of the cell
+outside of the nucleus.
+
+DALTONISM, the commonest form of color-blindness in which the affected
+individual is unable to discriminate between red and green.
+
+DENDRITES (Gr. _dendron_, tree), branching processes which spring from
+nerve-cells.
+
+DETERMINER (L. _determinare_, to determine), the distinctive cause or unit
+in a germ-cell which determines the development of a particular character
+in the individual derived from that cell. The terms _gene_ and _factor_
+are sometimes used as synonyms of determiner.
+
+DIHYBRIDS (L. _di_, two; _hybrida_, mongrel), the offspring of parents
+differing in two characters.
+
+DIPLOID (Gr. _diploos_, double; _eidos_, form), the dual or somatic number
+of chromosomes.
+
+DOMINANT CHARACTER (L. _dominare_, to be a master), a character from one
+parent which manifests itself in offspring to the exclusion of a
+contrasted character from the other parent.
+
+DROSOPHILA, a genus of fruit-flies of which there are several species.
+
+DUPLEX (L. _duo_, two; _plico_, fold), the condition in which a character
+is represented by two determiners, one from each parent.
+
+ELECTROTROPISM (Gr. _electron_, amber; _trope_, turning), defined, p. 198.
+
+EMBRYO (Gr. _embryon_), the young organism in its earliest stages of
+development.
+
+EMBRYOGENY (Gr. _embryon_; _genesis_, generation), the development of the
+embryo.
+
+EUGENICS (Gr. _eugenes_, well-born), the science relating to improvement
+of the human race through good breeding.
+
+FACTOR, the determiner of a particular hereditary character.
+
+FEEBLE-MINDEDNESS, deficiency in mental development. For grades, see p.
+244.
+
+FERTILIZATION, union of the sexual cells.
+
+FETUS (L. _feuere_, to bring forth), the unborn young animal in its later
+(after the second month in man) stages of development.
+
+FLAGELLUM (L. _flagellum_, little whip), a vibratile, thread-like organ of
+locomotion.
+
+GAMETE (Gr. _gamos_, marriage), a mature germ-cell.
+
+GENETICS (Gr. _genesis_, origin), the science which deals with heredity
+and the origin of individuals in general.
+
+GENOTYPE (Gr. _genea_, race; _typto_, strike), the germinal constitution
+of an organism.
+
+GEOTROPISM (Gr. _ge_, earth; _trope_, turning), defined, p. 198.
+
+GERM-CELL, a reproductive cell.
+
+GERMINAL VARIATIONS, variations which owe their origin to some
+modification in the germ-cells.
+
+GERM-PLASM, the material basis of inheritance.
+
+GONAD (Gr. _gonos_, generation), a germ-gland.
+
+HAPLOID (Gr. _haploos_, single; _eidos_, form), the single or reduced
+number of chromosomes as found, for instance, in the mature germ-cells.
+
+HELIOTROPISM (Gr. _helios_, sun; _trope_, turning), defined, p. 198.
+
+HEREDITY (L. _heres_, heir), resemblance of individuals to their
+progenitors based on community of origin.
+
+HERITAGE (L. _heres_, heir), all that is inherited by an individual.
+
+HETEROZYGOTE (Gr. _heteros_, other; _zygon_, yolk), an individual produced
+through the union of germ-cells which are unlike in one or more
+determiners. Adjective, _heterozygous_.
+
+HOMOZYGOTE (Gr. _homos_, same; _zygon_, yolk), an individual produced
+through the union of germ-cells which are alike in determiners. Adjective,
+_homozygous_.
+
+HYBRID (L. _hybrida_, mongrel), the offspring of parents which differ in
+one or more characters.
+
+IDENTICAL TWINS, twins which show identical inborn characters, both having
+come presumably from the same ovum.
+
+IDIOT (Gr. _idios_, peculiar, private), defined, p. 244.
+
+IMBECILE (L. _imbecillis_, weak), defined, p. 244.
+
+INHERITANCE (L. _in_, in; _heres_, heir), the sum of all characters which
+are transmitted by the germ-cells from generation to generation.
+
+INHIBITOR (L. _in_, in; _habeo_, hold, have), that which checks or
+restrains.
+
+INSTINCT (L. _in_, in; _stingno_, prick), defined, p. 203.
+
+INTRA-UTERINE (L. _intra_, within; _uterus_, the womb), within the womb.
+
+IRRITABILITY (L. _irrito_, excite), the property of responding to stimuli.
+
+LININ (L. _linum_, flax), filaments of the cell-nucleus not readily
+stained by dyes.
+
+LUETIN TEST (L. _lues_, pest), a test for syphilis; see p. 188.
+
+MAMMALS (L. _mamma_, breast), warm-blooded, hairy animals which suckle
+their young.
+
+MATURATION (L. _maturus_, ripe), the final stages in the development of
+the sex-cells characterized by two divisions in one of which the number of
+chromosomes is reduced by one-half.
+
+MENDELIAN, MENDELISM, referring to Mendel, the founder of a theory of
+heredity. See p. 67.
+
+METAZOA (Gr. _meta_, over; _zoon_, animal), all animals higher than the
+protozoa.
+
+MITOSIS (Gr. _mitos_, thread), indirect nuclear division, characterized by
+the appearance of a fibrous spindle and a definite number of chromosomes.
+The latter split to form daughter chromosomes which diverge to the poles
+of the spindle to form parts of the new nuclei.
+
+MONGOLIAN, a type of feeble-minded individual, see p. 248.
+
+MONOHYBRID (Gr. _monos_, single; L. _hybrida_, mongrel), the offspring of
+parents, differing in one character.
+
+MORON (Gr. _moros_, foolish), defined, p. 244.
+
+MUTATIONS (L. _mutare_, to change), abrupt, inheritable germinal
+variations. Frequently though not necessarily they are changes of
+considerable extent.
+
+NEURAL (Gr. _neuron_, nerve), pertaining to the nervous system.
+
+NEURON (Gr. _neuron_, nerve), a nerve-unit consisting of a nerve-cell with
+branching processes called dendrites and an axon or axis cylinder process
+which gives rise to a nerve fiber.
+
+NEUROPATHIC (Gr. _neuron_, nerve; _pathos_, suffering), relating to
+disease of the nervous system.
+
+NUCLEOLUS (L. dim. of nucleus), a well-defined body found within the
+nucleus of a cell.
+
+NUCLEUS (L. _nux_, a nut), the central organ of a cell.
+
+NULLIPLEX (L. _nullus_, not any; _plico_, fold), the condition in which no
+determiners of a given character exist in a particular individual.
+
+OOeCYTE (Gr. _oon_, egg; _kytos_, cell), the ovarian egg in one stage of
+development.
+
+OOeGENESIS (Gr. _oon_, egg; _genesis_, origin), the development of ova from
+primitive sex-cells.
+
+OOeGONIUM (Gr. _oon_, egg; _gonos_, generation), a primordial egg-cell.
+
+OVARY (L. _ovum_, egg), the organ in which the egg-cells multiply and are
+nourished.
+
+OVUM (L. _ovum_, an egg), the female sex cell.
+
+PARTHENOGENESIS (Gr. _parthenos_, virgin; _genesis_, origin), development
+of an egg which has not united with a male gamete.
+
+PHENOTYPE (Gr. _phaino_, show; _typto_, strike), the existing type of
+individual irrespective of hereditary possibilities which may reside in it
+undeveloped.
+
+PHOTOTROPISM (Gr. _phos_, light; _trope_, turning), defined, p. 198.
+
+PLACENTA (L. _placenta_, a flat cake), the organ by which the fetus of the
+higher mammals is attached to the uterine wall of the mother for purposes
+of nourishment, respiration and excretion. In it the maternal and fetal
+blood, although not intermingling, are brought into such close proximity
+that an interchange of dissolved substances is possible.
+
+POLAR BODIES, the minute cells which are separated from the egg in its
+maturation divisions.
+
+PRIMATE (L. _primus_, first), the highest order of animals, including
+monkeys, apes and man.
+
+PRONUCLEUS, the nucleus of the mature ovum or sperm-cell.
+
+PROTOPLASM (Gr. _protos_, first; _plasma_, form), the essential living
+substance.
+
+PROTOZOA (Gr. _protos_, first; _zoon_, animal), single-celled animals or
+animals composed of cells not separable into different tissues.
+
+PSYCHICAL (Gr. _psyche_, the soul), pertaining to the mind.
+
+RECESSIVE CHARACTER (L. _recessus_, a going back), a character from one
+parent which remains undeveloped in offspring when associated with the
+corresponding dominant character from the other parent.
+
+REDUCTION DIVISION, a division of the maturing germ-cells in which the
+dual or somatic (diploid) number of chromosomes is reduced to the single
+(haploid) number.
+
+REFLEX ACTION (L. _re_, back; _flectere_, bend), an automatic response of
+the nervous and motor mechanism of the body.
+
+RESTRICTIVE (or negative) EUGENICS, a system of improving the human race
+by preventing reproduction of the unfit.
+
+REVERSION (L. _re_, back; _verto_, turn), the reappearance of ancestral
+traits which have for some generations been in abeyance.
+
+RHEOTROPISM (Gr. _rheo_, to flow; _trope_, turning), defined, p. 198.
+
+SALPINGECTOMY (Gr. _salpinx_, trumpet; _ectome_, cutting out), removal of
+part or all of a Fallopian tube (oviduct).
+
+SEGREGATION (L. _se_, aside; _grex_, flock), separation.
+
+SEX CHROMOSOME, a special chromosome which is supposed to be concerned in
+the determination of sex.
+
+SEX-LINKED CHARACTERS, defined, p. 60.
+
+SIMIAN (L. _simia_, ape), ape-like.
+
+SIMPLEX (L. _sim_, same; _plico_, fold), the condition in which a
+character is represented by a determiner from only one of the two parents.
+
+SOMA (Gr. _soma_, body), the body considered apart from the germ-cells.
+
+SPERMATID (Gr. _sperma_, seed), a cell resulting from the last division of
+the germ-cell in spermatogenesis. It transforms into the spermatozoon.
+
+SPERMATOCYTES (Gr. _sperma_, seed; _kytos_, cell), cells concerned in the
+maturation divisions of the male germ-cells.
+
+SPERMATOGENESIS (Gr. _sperma_, seed; _genesis_, origin), the development
+of spermatozoa from primitive sex-cells.
+
+SPERMATOGONIUM (Gr. _sperma_, seed; _gonos_, generation), a primordial
+sperm-cell.
+
+SPERMATOZOON (Gr. _sperma_, seed; _zoon_, animal), the functional male
+sex-cell.
+
+SPINDLE, a fibrous organ formed in indirect cell-division.
+
+SPIREME (L. _spira_, coil), a characteristic stage preliminary to indirect
+cell-division in which the chromatin material of the nucleus appears in
+the form of a skein of filaments.
+
+STEREOTROPISM (Gr. _stereos_, solid; _trope_, turning), defined, p. 198.
+
+STERILIZATION (L. _sterilis_, barren), deprivation of reproductive power.
+For methods, see p. 322.
+
+SYNAPSE (Gr. _syn_, together; _hapto_, unite), the coming in contact of
+the processes of one nerve cell with the processes or body of another.
+
+SYNAPSIS (Gr. _syn_, together; _hapto_, unite), union of the chromosomes
+in pairs preliminary to the reduction division.
+
+TELEGONY (Gr. _telegonos_, born far away), the supposed influence of an
+earlier sire on offspring born later of the same mother to a different
+sire.
+
+THERMOTROPISM (Gr. _thero_, heat; _trope_, turning), defined, p. 198.
+
+THIGMOTROPISM (Gr. _thigmo_, touch; _trope_, turning), defined, p. 198.
+
+TOXIN (Gr. _toxicon_, poison), poisonous compounds of animal, vegetable,
+or bacterial origin.
+
+TROPISM (Gr. _trope_, turning), the automatic directing of an organism
+toward or away from a source of stimulus.
+
+UNIT-CHARACTER, a character which behaves as an indivisible unit in
+heredity.
+
+VASECTOMY (L. _vas_, vessel; _ektome_, cutting out), removal of a portion
+of the vas deferens (duct for conveying spermatozoa).
+
+VESTIGEAL (L. _vestigium_, footstep), representing organs which existed
+once in a more developed condition.
+
+VOLVOX (L. _volvo_, roll), a small fresh-water organism occurring in
+spherical colonies.
+
+WASSERMAN REACTION, a test for syphilis, see p. 188.
+
+X-ELEMENT, same as sex-chromosome.
+
+ZYGOTE (Gr. _zygon_, yolk), the product of the union of two gametes.
+
+
+
+
+REFERENCES FOR FURTHER READING AND STUDY
+
+
+BATESON, W., 1909. _Mendel's Principles of Heredity._ Cambridge, The
+University Press. The best technical account of Mendelism. It contains
+also a translation of the original papers of Mendel.
+
+CASTLE, WILLIAM E., 1911. _Heredity._ New York, D. Appleton and Company.
+
+CASTLE, WILLIAM E.; COULTER, JOHN M.; DAVENPORT, CHARLES B.; EAST, EDWARD
+M.; TOWER, WILLIAM L., 1912. _Heredity and Eugenics._ Chicago, The
+University of Chicago Press.
+
+CONKLIN, EDWIN GRANT, 1915. _Heredity and Environment in the Development
+of Men._ Princeton, Princeton University Press.
+
+DAVENPORT, CHARLES B., 1911. _Heredity in Relation to Eugenics._ New York,
+Henry Holt and Company.
+
+DONCASTER, L., 1911. _Heredity in the Light of Recent Research._
+Cambridge, The University Press.
+
+DONCASTER, L., 1915. _The Determination of Sex._ Cambridge, The University
+Press.
+
+ELLIS, HAVELOCK, 1912. _The Task of Social Hygiene._ New York, Houghton
+Mifflin Company.
+
+GALTON, FRANCIS, 1869. _Hereditary Genius: an Inquiry Into Its Laws and
+Consequences._ London, Macmillan and Company.
+
+GALTON, FRANCIS, 1889. _Natural Inheritance._ New York, The Macmillan
+Company.
+
+GALTON, FRANCIS, 1895. _English Men of Science; Their Nature and Nurture._
+New York, D. Appleton and Company.
+
+GALTON, FRANCIS, and SCHUSTER, EDGAR, 1906. _Noteworthy Families_ (Modern
+Science). London, J. Murray.
+
+GODDARD, HENRY HERBERT, 1912. _The Kallikak Family; a Study in the
+Heredity of Feeble-mindedness._ New York, The Macmillan Company.
+
+GODDARD, HENRY HERBERT, 1914. _Feeble-mindedness; Its Causes and
+Consequences._ New York, The Macmillan Company.
+
+HEALY, WILLIAM, 1915. _The Individual Delinquent._ Boston, Little, Brown
+and Company.
+
+KELLICOTT, WILLIAM E., 1911. _The Social Direction of Human Evolution; an
+Outline of the Science of Eugenics._ New York, D. Appleton and Company.
+
+MORGAN, THOMAS HUNT, 1913. _Heredity and Sex._ New York, Columbia
+University Press.
+
+PUNNETT, R. C., 1911. _Mendelism._ New York, The Macmillan Company. The
+best popular account of Mendelism.
+
+SALEEBY, CALEB WILLIAM, 1909. _Parenthood and Race Culture; an Outline of
+Eugenics._ London, Cassell and Company.
+
+SCHUSTER, EDGAR, 1912. _Eugenics._ London, Collins Clear-Type Press.
+
+THOMSON, J. ARTHUR, 1908. _Heredity._ London, John Murray.
+
+WALTER, HERBERT EUGENE, 1913. _Genetics._ New York, The Macmillan Company.
+
+WHETHAM, W. C. D. and C. D., 1909. _The Family and the Nation._ London,
+Longmans, Green and Company.
+
+WOODS, FREDERICK ADAMS, 1906. _Mental and Moral Heredity in Royalty._ New
+York, Henry Holt and Company.
+
+VARIOUS AUTHORS, 1914. _Eugenics; Twelve University Lectures._ New York,
+Dodd, Mead and Company.
+
+JOURNALS:
+
+    _The Journal of Heredity._ The organ of the American Genetic
+    Association, Washington, D. C.
+
+    _The Eugenics Review._ Issued at the University of London.
+
+    _Memoirs and Bulletins_ published by the Eugenics Record Office, Cold
+    Spring Harbor, Long Island, N. Y.
+
+Every one interested in eugenics should be acquainted with the work of
+this office. In its own words its functions are:
+
+    1. To serve eugenical interests in the capacity of repository and
+    clearing house.
+
+    2. To build up an analytical index of the traits of American families.
+
+    3. To train field workers to gather data of eugenical import.
+
+    4. To maintain a field force actually engaged in gathering such data.
+
+    5. To cooperate with other institutions and with persons concerned
+    with eugenical study.
+
+    6. To investigate the manner of inheritance of specific human traits.
+
+    7. To advise concerning the eugenical fitness of proposed marriages.
+
+    8. To publish results of researches.
+
+    To such persons as will undertake to fill them out it furnishes free
+    in duplicate (one copy to be retained by the applicant) the following
+    blank schedules: 1. _Record of Family Traits._ 2. _Index to
+    Germ-plasm--A Parallel Family Record for Prospective Marriage Mates._
+    3. _Musical Talent._ 4. _Mathematical Talent._ 5. _Tuberculosis._ 6.
+    _Special Trait Chart._ 7. _Harelip and Cleft-palate._
+
+    _Publications of the Volta Bureau_ of Washington, D. C., an
+    institution given over entirely to data regarding deaf mutes.
+
+    _Studies in National Deterioration._ The University of London.
+
+    _Memoirs and Lectures_, from the Biometric Laboratory, University of
+    London.
+
+    _Treasury of Human Inheritance_, a series of studies being issued from
+    the Eugenics Laboratory, University College, London.
+
+
+
+
+INDEX
+
+
+  Ability: 118;
+    calculating, literary, musical, 120.
+
+  Able child likely to be neglected, 257.
+
+  Achondroplasy, 113.
+
+  Acquired characters, inheritance of, 121.
+
+  Adami, 164.
+
+  Adaptations, establishment of, 140.
+
+  Adaptive responses, 201.
+
+  Agassiz, 297.
+
+  Albinism, in man, 116.
+
+  Alcohol: and crime, 279;
+    and degeneracy, 172, 179;
+    and germinal tissue, 172;
+    a poison, 168.
+
+  Alcoholism: 101, 117, 167;
+    factors in, 180;
+    in lower animals, 173-178;
+    views regarding inheritance of, 169, 170, 172, 178, 179, 180.
+
+  Alkaptonuria, 117.
+
+  Allelomorph, 77.
+
+  Alpine plants, non-inheritance of acquired characters, 131.
+
+  Alternative action in behavior, 207.
+
+  Altruism, possible origin of, 220.
+
+  Ambystoma, 132.
+
+  Ameba, 23, 24.
+
+  Ancestors, number of, 4.
+
+  Ancestry: a network, 3;
+    dual, 6;
+    in royalty, 5;
+    pride of, as a eugenic agent, 309.
+
+
+  Backward child, 256.
+
+  Backwardness, importance of early determination, 256, 257.
+
+  Bardeen, 126.
+
+  Barker, 229.
+
+  Barr, 246, 247, 248.
+
+  Barrington, 179.
+
+  Bateson, 77, 82.
+
+  Bees, inheritance in, 136, 137.
+
+  Behavior: lower animals, 197;
+    modifiability of, 200, 204-207, 217, 219, 224, 225, 337;
+    not wholly established by heredity, 217, 227;
+    rational, 205, 206;
+    various forms of, possible, 207, 219.
+
+  Bell, 152.
+
+  Bezzola, 170.
+
+  Billings, 249.
+
+  Binet-Simon test, 255.
+
+  Biometry, 16.
+
+  Birthmarks, 159, 160.
+
+  Birth-rate: significance of, 302;
+    too low in desirable stocks, 302, 304, 305, 307.
+
+  Blastomeres, 55.
+
+  Blastophthoria, 163.
+
+  Blended inheritance, 87, 92, 93.
+
+  Blends, mistakes for, 91.
+
+  Blindness, infantile, 183.
+
+  Blistering, 113.
+
+  Body: how built up from germ, 36;
+    duality of, 50.
+
+  Brachydactylism, 107.
+
+  Brain: in higher animals, 213;
+    mechanism, maladjustments of, 230.
+
+  Branthwaite, 180, 292.
+
+  Breeding, experiments, method of, 14, 15.
+
+  Brewer, 142.
+
+  Brieux, 101.
+
+  Bronner, 266.
+
+  Brown Sequard, 132, 133.
+
+
+  Cabot, 183.
+
+  Cacogenic strains, 310.
+
+  Cajal, 209.
+
+  Cancer, 117, 154.
+
+  Capsella, 131.
+
+  Castle, 134.
+
+  Cataract, presenile, 112.
+
+  Cattle: horn characters, 79;
+    roan, 81.
+
+  Cell: a unit of structure, 20;
+    diagram of, 21;
+    structure of, 20, 30.
+
+  Cell-division: 31;
+    indirect (mitosis), 32;
+    meaning of indirect, 34.
+
+  Cell-theory, 22.
+
+  Cellular basis of heredity, 22.
+
+  Ceni, 174.
+
+  Centrosome, 31.
+
+  Cerebral cortex, not functionally homogeneous, 211.
+
+  Character: defined, 12;
+    dominant, 74;
+    recessive, 74.
+
+  Characters: contrasted, 69;
+    determiners of, 13, 14;
+    independence of, 69;
+    inheritable and non-inheritable, 121, 122;
+    more than two pairs of, 87;
+    new combinations of, 82, 83, 84;
+    separable, 69;
+    symbols for, 78;
+    two pairs of, 82.
+
+  Chauvin, 132.
+
+  Chemotropism, 198.
+
+  Childbirths, intervals between, 165.
+
+  Children of the future: ours to determine quality of, 338, 339;
+    and home, 338.
+
+  Cholera, 152.
+
+  Chorea: 117;
+    Huntington's, 113-115, 243, 325.
+
+  Chromatin, 31.
+
+  Chromosome, 32.
+
+  Chromosomes: individuality of, 39, 48;
+    determiners in, 94;
+    in germ and body cells, 40;
+    Mendelian factors and, 93;
+    number and appearance, 34, 41;
+    pairs of, 40, 93, 94;
+    significance of, in heredity, 35, 49, 50, 51, 53, 54.
+
+  Chromotropism, 198.
+
+  Church, 242.
+
+  Cleavage, 36.
+
+  Cleft-palate, 178.
+
+  Cole, 166.
+
+  College graduates and birth-rate, 304.
+
+  Coloboma, 113.
+
+  Color-blindness, 60-62.
+
+  Conceptual thought, origin of, 206.
+
+  Conduct: importance to young of practise, 221, 223;
+    hereditary predisposition and, 218, 337;
+    responsibility for, 195.
+
+  Congenital traits, 123.
+
+  Conjugation, 25.
+
+  Consciousness, 206.
+
+  Conservation: of superior strains, 157;
+    human, 299, 300.
+
+  Constructive eugenics, 309.
+
+  Corneal opacity, 113.
+
+  Correns, 68.
+
+  Cortex of brain, 195, 213.
+
+  Cost, of caring for our disordered and delinquent, 257, 300.
+
+  Cretins, effects of segregating the sexes, 321.
+
+  Crime: and delinquency, 263, 287;
+    and feeble-mindedness, 264-270;
+    bearings of immigration on, 280;
+    classifications of, 276;
+    defined, 276;
+    heredity vs. environment in, 263;
+    increase in, 272;
+    mental disorders most frequently associated with, 279;
+    no specific hereditary factor for, 275.
+
+  Criminal: the born, 277;
+    the epileptic, 277.
+
+  Criminality, 117.
+
+  Criss-cross inheritance, 61.
+
+  Criteria for judging reproductive fitness, 304, 306.
+
+  Cytoplasm: 30;
+    in heredity, 51.
+
+
+  Daltonism, 60.
+
+  Dana, 257.
+
+  Darwin, pedigree of, 316.
+
+  Davenport, 92, 116, 231, 243, 257, 271, 273, 284, 291, 304, 312.
+
+  Davis, 185.
+
+  Deaf-mutism, 152, 153.
+
+  Death, natural, 28.
+
+  Decline of nations, 290, 300.
+
+  Defective delinquent, should prevent procreation of, 335.
+
+  Defectives: increase due to breeding, 290, 291;
+    natural elimination done away with among, 292;
+    unpardonable to let multiply, 288.
+
+  Defects: breeding out, 118, 119;
+    mental and nervous, 228.
+
+  Degenerate strains: 269;
+    not a product of surroundings, 273.
+
+  Degenerates, sterilization of married, 330.
+
+  Delinquency, causes of, 267, 274.
+
+  Delinquents not all defectives, 274.
+
+  Delinquent women and girls, many mentally defective, 265, 266.
+
+  Dendrite, 208.
+
+  De Sanctis, 256.
+
+  Determiners: 13, 77;
+    different producing the same character, 88, 90;
+    segregation of, 84.
+
+  Development: in higher organisms, 28;
+    suppressed, 9.
+
+  De Vries, 68.
+
+  Diabetes, 113.
+
+  Difficulty, educational value of, 222, 223.
+
+  Digital malformations, 107.
+
+  Dihybrids, 82.
+
+  Diploid number of chromosomes, 41, 43.
+
+  Disease: defined, 146;
+    inheritance of, 98, 148;
+    predisposition to, 148;
+    reappearance of not necessarily inheritance, 146.
+
+  Dominance: 74;
+    delayed, 81;
+    incomplete, 80, 100;
+    in human genealogies, 102;
+    in man, 99, 107.
+
+  Don Carlos, number of ancestors, 5.
+
+  Drosophila, 66.
+
+  Duplex character, 80, 99.
+
+  Dwarfing, by starvation, 130.
+
+  Dwarfs, true, 117.
+
+
+  East, 91.
+
+  Education: actual practise in carrying out projects important, 221;
+    affording opportunity for development of good traits, 226;
+    effects of not inherited, 142, 155;
+    establishing pathways through the nervous system, 210;
+    importance of difficulty in, 222, 223;
+    non-transference of skill acquired in one line to other lines, 213;
+    providing proper stimuli, 226;
+    training in motive necessary, 220;
+    value of interest in, 223.
+
+  Egg, a cell, 22.
+
+  Egg-cell and sperm-cell contrasted, 29.
+
+  Elderton, 179, 296.
+
+  Electrotropism, 198.
+
+  Ellis, 265, 301.
+
+  Embryo, relation to mother, 161.
+
+  Embryogeny, 36.
+
+  Emerick, 251.
+
+  Environment: direct action on germ cells, 124, 125;
+    effects of faulty, 158;
+    in crime and delinquency, 263, 266, 273, 274.
+
+  Epidermolysis, 113.
+
+  Epilepsy: 101, 117, 242, 249, 251, 252, 253;
+    in guinea-pigs, 132;
+    relation to feeble-mindedness, 249.
+
+  Epileptic, the criminal type, 277-279.
+
+  Epileptics, number of, 230, 246, 250.
+
+  Eugenic agent, educated public sentiment, 330.
+
+  Eugenics: and education, 309;
+    and personal liberty, 332;
+    a working program of, 335;
+    constructive, based on education, 301;
+    defined, 293;
+    desirable traits, 306;
+    education of women in, 333;
+    influence of public opinion on, 331;
+    much yet to be done, 333, 334;
+    positive and negative, 301.
+
+  Ewart, 10, 165.
+
+  Exceptional child likely to be neglected, 257.
+
+  Experimental breeding, method of, 15.
+
+  External conditions, influences of, 130.
+
+  Eye-color: 9, 103;
+    inheritance of, 104.
+
+  Eye-defects, 108, 110.
+
+
+  Family pride and eugenics, 309.
+
+  Farabee, 106.
+
+  Fay, 153.
+
+  Feeble-minded: prevention of procreation in, 258, 335;
+    results of non-restraint, 246.
+
+  Feeble-mindedness: 101, 117;
+    and crime, 264-269, 279;
+    grades of, 244;
+    inheritance of, 245;
+    not insanity, 238;
+    relation of alcohol to, 169-172.
+
+  Fernald, 256, 266.
+
+  Fertilization, 26, 29, 47, 48.
+
+  Fetus: poisoning of, 162;
+    relation to mother, 161.
+
+  Fiber-tracts in man, 214.
+
+  Fitness, criteria for judging, 304, 306.
+
+  Flexner, 186.
+
+  Forel, 169, 173, 303.
+
+  Fowl, Andalusian, 69, 70, 71.
+
+  Frederick the Great, number of ancestors, 5.
+
+  Friedreich's disease, 117.
+
+  Fruit-fly, 66.
+
+
+  Galton, 293, 295.
+
+  Gamete, 28, 40.
+
+  Gametes in dihybrids, 85.
+
+  Gametic matings in man, 100.
+
+  Geddes, 55.
+
+  Genealogies, imperfect, 98.
+
+  Genotype, 86.
+
+  Geotropism, 198.
+
+  Germ and body distinct, 37, 38.
+
+  Germ: control of possibilities in, 224;
+    singleness of, 50.
+
+  German emperor, number of ancestors, 5.
+
+  Germ-cells: affected by poisons, 126;
+    changes in, 126, 127;
+    early set apart, 37;
+    question of effects of body on, 128, 135;
+    effects of external influences on, 124;
+    in Miastor, 37, 38;
+    metabolic changes in, 138;
+    origin of, 36, 37;
+    possibilities of development, 127;
+    two classes of, 71, 73.
+
+  Germinal continuity, 39.
+
+  Germinal variation and the origin of new characters: 138;
+    cases analyzed, 141;
+    sexual reproduction in relation to, 138.
+
+  Germ-plasm and bad environment, 194.
+
+  Gifted persons, 212.
+
+  Glaucoma, 113.
+
+  Goddard, 118, 171, 174, 188, 235, 238, 245, 250, 256, 257, 264, 269, 326.
+
+  Gonads, transplantation of, 134.
+
+  Gonorrhoea: seriousness of, 182;
+    prevalence, 183.
+
+  Gorst, 234.
+
+  Gout, 153, 234.
+
+  Guinea-pigs: alcoholism in, 175;
+    Mendelism in, 75.
+
+  Guyer, 59.
+
+
+  Habit, 219.
+
+  Habits, modification of in lower animals, 204.
+
+  Hair-color, 105.
+
+  Hair shape, 105.
+
+  Hamburger, 150.
+
+  Handwriting, 120.
+
+  Haploid number of chromosomes, 41, 43.
+
+  Harelip, 178.
+
+  Hart, 266, 319, 326.
+
+  Healy, 256, 274, 278.
+
+  Hearing, hardness of, 118.
+
+  Heart disease, 154.
+
+  Hegner, 27, 38.
+
+  Heliotropism, 198.
+
+  Helm, 109, 111.
+
+  Hemophilia, 64.
+
+  Hereditary character defined, 12.
+
+  Hereditary mingling, mosaic rather than blend, 13.
+
+  Hereditary transmission, laws of, 68.
+
+  Heredity: and environment, 295;
+    dual ancestry in, 6;
+    defined, 1;
+    false, 163;
+    human, uncertainty of records, 98;
+    in protozoa, 22, 23;
+    in insanity, importance of, 261;
+    in sexually reproducing forms, 7;
+    in unicellular forms, 22, 23;
+    methods of study, 14, 15;
+    new discoveries in, 67;
+    not a blend, 13;
+    race betterment through, 289.
+
+  Heritage, blood, 1.
+
+  Heron, 307.
+
+  Heterozygote: 80;
+    detection of, 80.
+
+  Hill-folk, the, 271.
+
+  Hodge, 175.
+
+  Holmes, 203.
+
+  Home, for children, 338.
+
+  Homozygote, 80.
+
+  Huntington's chorea, 113-115, 243, 325.
+
+  Huxley, 195, 205.
+
+  Hybrids: 52;
+    whites and negroes, 297, 298.
+
+  Hypotrichosis, 113.
+
+  Hysteria, 117.
+
+
+  Ichthyosis, 65.
+
+  Ideals, importance of establishing in children, 223.
+
+  Idiots, 244.
+
+  Imbeciles, 244.
+
+  Immigrants, duty of excluding undesirable, 335.
+
+  Immigration: and mental unsoundness, 281, 282;
+    bearing on crime and delinquency, 280;
+    bearing on venereal diseases, 282;
+    importance of restricting, 283, 335.
+
+  Immortality: of protozoa, 23;
+    of the race, 3.
+
+  Immunity, artificial, not inherited, 155.
+
+  Inbreeding, in defectives, 271.
+
+  Individual, and race, 3.
+
+  Inebriate women, offspring of, 168.
+
+  Inebriety, constitutional, 180.
+
+  Infant mortality, 149.
+
+  Infection, prenatal, 147.
+
+  Inheritance: and disease, 146;
+    blended, 87, 93;
+    of tendencies, 107.
+
+  Inhibitions, 216.
+
+  Inhibitors, 79.
+
+  Insane, increase in numbers of, 233, 234.
+
+  Insanity: 117;
+    certain forms recessive, 243;
+    eugenical significance of, 234, 235, 240;
+    importance of early diagnosis, 259;
+    some forms not hereditary, 260;
+    types of, 239;
+    prevalence in the United States, 228, 229.
+
+  Insect colors, effect of temperature, 129.
+
+  Instincts: 203;
+    adjustable, 203;
+    not inherited acquirements, 144;
+    origin of intelligent behavior from, 203, 204.
+
+  Institutional figures misleading, 266.
+
+  Intelligence, 205, 206.
+
+  Intelligent behavior, opening up possibilities of, 204.
+
+  Ireland, 171.
+
+  Irritability, characteristics of living protoplasm, 197.
+
+
+  Jennings, 203, 204.
+
+  Johnson, 305.
+
+  Johnstone, 245, 319, 320, 321.
+
+  Jolly, 243.
+
+  Jordan, 4, 299.
+
+  Jukes, 270.
+
+
+  Kallikak family, 269, 270.
+
+  Kellicott, 314, 316.
+
+  Kellogg, 299.
+
+  Keratosis, 113.
+
+  Kidney diseases, 154.
+
+  Kirby, 187, 324.
+
+  Knox, 256.
+
+  Kraeplin, 242.
+
+
+  Laitinen, 174.
+
+  Language, as mental aid, 206, 207.
+
+  Lapsed intelligence, theory of, 145.
+
+  Larval stages, susceptibility of, 128.
+
+  Laws, sterilization, 323, 327, 329.
+
+  Lead-poisoning: 163;
+    experiments on rabbits, 163.
+
+  Lederbaur, 131.
+
+  Legal restraint of defectives limited, 331.
+
+  Lens: displaced, 113;
+    cataract, 112.
+
+  Leprosy, 152.
+
+  Leptinotarsa, production of variations in, 125.
+
+  Linden, Countess von, 129.
+
+  Linin, 31.
+
+  Little's disease, 215.
+
+  Locomotor ataxia, 187.
+
+  Loeb, 62, 203.
+
+  Longevity, 120.
+
+  Lord Morton's mare, 10.
+
+  Lorenz, 113, 114, 115.
+
+  Low birth-rate, 308.
+
+  Lowell, Judge John, 312.
+
+  Luetin test, 188.
+
+  Lunborg, 243.
+
+
+  MacDougal, 125.
+
+  Margaret, Mother of Criminals, 270.
+
+  Marriage: barriers to, 331;
+    inter-racial, 296;
+    medical inspection before, 191.
+
+  Mast, 203.
+
+  Maternal impressions, 159-160.
+
+  Maturation: 39, 41, 43, 44;
+    parallel between egg and sperm-cell, 44, 46.
+
+  Mechanical skill, 120.
+
+  Mechanism of heredity, 22, 25, 26, 28, 29, 30, 35, 37, 40-54, 94, 95.
+
+  Melancholia and crime, 279.
+
+  Memory: 120, 204;
+    not a complete test of normality, 268, 269.
+
+  Mendel: 68;
+    work on peas, 82.
+
+  Mendelian factors and chromosomes: 93;
+    inheritance and man, 97;
+    principles, rediscovery of, 68;
+    ratio, cause of, 71.
+
+  Mendelism, 67, 69.
+
+  Mental and nervous defects, 228.
+
+  Mental defective: defined, 255;
+    disproportionate increase in, 232;
+    numbers married, 231, 232;
+    inefficiency of marriage laws concerning, 315.
+
+  Mental deficiency: not always inherited, 248;
+    tests for, 254, 255.
+
+  Mental organization of lower vertebrates, 205.
+
+  Mental process as neural process, 195.
+
+  Mental unsoundness, 196.
+
+  Mentality, inheritance of, 19.
+
+  Mentally disordered, cost of caring for, 257, 258.
+
+  Mercier, 279.
+
+  Merriere's disease, 117.
+
+  Metazoa, 28.
+
+  Metz, 41.
+
+  Mice, 78.
+
+  Michigan, state report on mentally defective, 234.
+
+  Migraine, 101.
+
+  Mind, relation to brain, 195.
+
+  Mitosis: 32, 33;
+    meaning of, 34, 37.
+
+  Mjoeen, 171.
+
+  Modifiability of behavior, 200, 204, 205, 207, 217, 219, 224, 225, 337.
+
+  Mongolians, 248.
+
+  Moral responsibility, 227.
+
+  Morgan, C. Lloyd, 146, 211.
+
+  Morgan, T. H., 59, 66.
+
+  Moron, 244, 268.
+
+  Morons and crime, 268.
+
+  Mosaic, heredity a, 13.
+
+  Motherhood, safeguarding, 165.
+
+  Motive, training in, 220.
+
+  Mott, 150.
+
+  Mulattoes, 92.
+
+  Multiple sclerosis, 64, 117.
+
+  Muscular atrophy: 113;
+    Gower's, 65.
+
+  Musical ability, 120.
+
+  Mutations: artificial production of, 125;
+    germinal, 125.
+
+  Mutilations, non-inheritance of, 134.
+
+  Myopia, 64.
+
+
+  Naegeli, 131.
+
+  Nam family, 271.
+
+  Natural selection partly done away with in human society, 292.
+
+  Near-sightedness, 64.
+
+  Nervous and mental diseases, 153.
+
+  Nervous organization, inheritable, 242.
+
+  Nervous response, in lower organisms, 196.
+
+  Nervous system: mainly inherited, 210, 216;
+    establishment of pathways in, 210;
+    maladjustments of, 231;
+    special developments in man, 213, 214, 215;
+    units of, 208.
+
+  Nervous systems of anthropoids, 214.
+
+  Neural pathways, not all established at birth, 217.
+
+  Neuritis optica, 65.
+
+  Neurons, 208.
+
+  Neuron theory, 208.
+
+  Neuropathic constitution, expression of, 241.
+
+  Neuropathic defects, carriers of, 253.
+
+  Neuter insects, heredity in, 136, 137.
+
+  New characters, origin of, 138.
+
+  Newman, 56.
+
+  Nicloux, 172.
+
+  Night-blindness, 65.
+
+  Nilsson-Ehle, 88, 89.
+
+  Noguchi, 186.
+
+  Nucleolus, 31.
+
+  Nucleus, structure of, 31.
+
+  Nulliplex character, 80, 100.
+
+
+  Obesity, 120, 154.
+
+  Offspring: from one parent only, 5;
+    different from either parent, 12.
+
+  Ooecyte, primary, secondary, 44.
+
+  Ooegenesis, 44.
+
+  Ooegonia, 44.
+
+  Optic nerve, atrophy of, 64.
+
+  Organs, formation of, 36.
+
+  Origin of sex cells, 12, 36.
+
+  Ovaries, transplantation of, 134.
+
+  Ovum, 26, 40.
+
+
+  Paralysis, general, 186.
+
+  Paranoia, 279.
+
+  Parent-body and germ distinct, 12.
+
+  Parenthood, cultivation of wholesome sentiment toward, 336.
+
+  Paresis: 186;
+    and crime, 279.
+
+  Parthenogenesis, 6.
+
+  Patterson, 56.
+
+  Paul, 163.
+
+  Pearson, 150, 151, 179, 296, 307.
+
+  Peas, 68, 82.
+
+  Performance tests, 256.
+
+  Peron, 133.
+
+  Personality determined by heredity, 2, 195.
+
+  Peterson, 242.
+
+  Phenotype, 86.
+
+  Phillips, 134, 135.
+
+  Phototropism, 198.
+
+  Pinard, 165.
+
+  Pineys, the, 271.
+
+  Plato, 290.
+
+  Poellman, 271.
+
+  Polar bodies, 44, 45.
+
+  Polydactyly, 108.
+
+  Potato-beetle, production of variations in, 125.
+
+  Potts, 292.
+
+  Predisposition to disease, 148.
+
+  Pregnancy, neglect of mothers during, 165.
+
+  Prenatal care: 336;
+    infection, 147;
+    influence, 11, 159, 162.
+
+  Prenuptial medical inspection desirable, 336.
+
+  Presence and absence theory: 78;
+    formulae for man, 99.
+
+  Primrose, experiments on, 125.
+
+  Principles, Mendelian, 68.
+
+  Prisoners, many mentally subnormal, 266.
+
+  Pronucleus, 47.
+
+  Protective coloration, not of somatic origin, 135, 136.
+
+  Protoplasm, germinal, 39.
+
+  Psychical development, 196, 203, 205, 206, 213, 215.
+
+  Pyramidal tracts, 214.
+
+
+  Quagga hybrid, 10.
+
+
+  Race amalgamation: 297, 298;
+    deterioration, in a selected population, 303.
+
+  Racial degeneracy, not curable by improved environment alone, 294.
+
+  Ratio: the 1:2:1, 73;
+    the 3:1, 77;
+    the 9:3:3:1, 85;
+    the 27:9:9:9:3:3:3:1, 87;
+    the 15:1, 88;
+    the 63:1, 90.
+
+  Rational behavior, 205, 206.
+
+  Reason, 206.
+
+  Recessiveness: 74;
+    in man, 115.
+
+  Records of family traits desirable, 337.
+
+  Reduction division, 41, 42.
+
+  Reflexes, 203.
+
+  Regression, law of, 17.
+
+  Renault, 172.
+
+  Rentoul, 232.
+
+  Reproduction: asexual, 6, 26;
+    sexual, 26;
+    sexual and variation, 139.
+
+  Reproductive cells, 27, 28, 29.
+
+  Responsibility for conduct, 195.
+
+  Rest, importance of, in pregnancy, 165.
+
+  Reversion: 7, 8;
+    and atavism, 8;
+    in guinea-chicken hybrids, 8.
+
+  Rheotropism, 198.
+
+  Rheumatism, 154.
+
+  Ritter, 143.
+
+  Rogers, 246, 272.
+
+  Romanes, 133.
+
+  Rosanoff, 243.
+
+  Rossolimo, 256.
+
+  Rudin, 243.
+
+
+  Salpingectomy, 322.
+
+  Sanford, 205.
+
+  St. Vitus' dance, 117.
+
+  Schulze, 24.
+
+  Schuster, 296.
+
+  Sclerosis, multiple, 64, 117.
+
+  Segregation: in dihybrids, 84;
+    Mendelian, 69, 70, 75;
+    of defectives, 318.
+
+  Seguin, 256.
+
+  Self-control, importance of, 221, 267, 268, 284, 286, 287.
+
+  Sex: and chromosomes, 59;
+    and heredity, 53;
+    cells of Volvox, 25;
+    chromosome, 57, 58;
+    determination, 55;
+    differentiation and X-element, 60;
+    evolution of, 25-30;
+    hygiene, question of school instruction in, 285;
+    in certain insects, 56;
+    linked characters, 60, 65;
+    not a necessary factor in heredity, 6;
+    problem, knowledge alone not sufficient, 286.
+
+  Sexual vice, 284.
+
+  Sharp, 322.
+
+  Simplex character, 80, 99.
+
+  Skill, non-transference in brain, 212, 213.
+
+  Skin, color of, 92.
+
+  Smallpox, 152.
+
+  Social maladies, prevention of, 293.
+
+  Softening of the brain, 186.
+
+  Soma, 28.
+
+  Spermatid, 43.
+
+  Spermatocyte, primary, secondary, 43.
+
+  Spermatogenesis, 42.
+
+  Spermatogonium, 43.
+
+  Spermatazoon: 26, 40;
+    a cell, 22;
+    formation of, 43;
+    structure of, 43.
+
+  Spindle, in cell-division, 32.
+
+  Spottedness of hair-coat, 113.
+
+  Sprague, 281, 305.
+
+  Starfish, training a, 204.
+
+  Statistical methods, 15.
+
+  Statistics, trustworthy needed, 334.
+
+  Stature, inheritance of, 17.
+
+  Stereotropism, 198.
+
+  Sterility, 182.
+
+  Sterilization: 322;
+    in epilepsy, 326;
+    laws, 323;
+    laws, on trial, 329;
+    laws, states having, 327.
+
+  Stevens, 41.
+
+  Stockard, 174-178.
+
+  Strength, muscular, 120.
+
+  Stripes, reversionary, 8.
+
+  Stutzman, 305.
+
+  Sullivan, 168.
+
+  Superior strains, conservation of, 157.
+
+  Synapse, 210.
+
+  Synapsis, 41, 42.
+
+  Syndactyly, 65, 108, 111.
+
+  Syphilis: 184-190;
+    and prostitutes, 185;
+    cerebro-spinal form, 189-190;
+    prenuptial inspection for, 190-192;
+    prevalence, 186;
+    stages of, 185;
+    tests for, 188.
+
+  Syphilitics: children of, 187, 188;
+    married, 190.
+
+
+  Tabes dorsalis, 186.
+
+  Taints, 101.
+
+  Talent, inheritance of, 212.
+
+  Taylor, 297.
+
+  Telegony, alleged cases of, 10.
+
+  Temperament, inheritance of, 19.
+
+  Thermotropism, 198.
+
+  Thigmotropism, 198.
+
+  Third generation, segregation in, 69.
+
+  Thomsen's disease, 118.
+
+  Thomson, 55.
+
+  Thorndike, 296.
+
+  Tower, 125.
+
+  Training of children: and heredity, 218;
+    faults in, 221, 222.
+
+  Transmission, not necessarily inheritance, 163.
+
+  Tredgold, 170.
+
+  Treponema pallidum, 185.
+
+  Tribe of Ishmael, 271.
+
+  Tropic responses: often purposeful, 201;
+    uncertainties in, 202.
+
+  Tropisms: 197;
+    complications in, 200;
+    in plants and animals, 198;
+    relations to reflex actions and instincts, 203.
+
+  Tschermak, 68.
+
+  Tuberculosis, 118, 148-160, 162.
+
+  Twins: identical, 55;
+    sex of, 55.
+
+  Typhoid, 152.
+
+
+  Unemployed, frequently morons, 280.
+
+  Unfit, elimination of, urgent, 313.
+
+  Unit-character: 12;
+    inheritance of, 13.
+
+  Unicellular organisms: 21;
+    inheritance in, 22, 23.
+
+  Use and disuse, 122.
+
+
+  Van Ingen, 167.
+
+  Vasectomy, 322.
+
+  Venereal disease, 182.
+
+  Virchow, 147.
+
+  Voison, 133.
+
+  Volitions as tropisms, 199.
+
+  Volvox, 25, 26, 27.
+
+
+  War, eugenical effects of, 299.
+
+  Wasserman, provocative, 189.
+
+  Wasserman test, 188, 189.
+
+  Webbed digits, 65.
+
+  Weeks, 251, 252, 253, 291.
+
+  West, 167.
+
+  Wheat, 75, 81, 88.
+
+  Whetham, 314, 316.
+
+  Whitman, 145.
+
+  Wilmarth, 243, 245, 274, 291.
+
+  Wilson, 59, 62, 94, 95.
+
+  Woods, 296.
+
+
+  X-element, 57, 58.
+
+
+  Zebra hybrids, 10.
+
+  Zeros, the, 271.
+
+  Zygote: 26, 27;
+    chromosomes of, 40.
+
+
+
+
+FOOTNOTES:
+
+[1] The reader desiring more detailed information will find fuller
+discussions in the following:
+
+Wilson, E. B.: _Recent Researches on the Determination and Heredity of
+Sex_. Science, January 8, 1909.
+
+Wilson, E. B.: _The Chromosomes in Relation to the Determination of Sex_.
+Science Progress, April, 1910.
+
+Guyer, M. F.: _Recent Progress in Some Lines of Cytology_. Transactions of
+the American Microscopical Society, April, 1911.
+
+Morgan, T. H.: _Heredity and Sex_. Columbia University Press, 1913.
+
+[2] A translation of Mendel's original papers will be found in _Mendel's
+Principles of Heredity_, by W. Bateson.
+
+[3] _Heredity of Skin Color in Negro and White Crosses_: Publication No.
+188, of the _Carnegie Institution of Washington_.
+
+[4] Whitman, C. O.: _Animal Behavior, Biological Lectures_, Marine
+Biological Laboratory, 1898.
+
+[5] _The Fight Against Tuberculosis and the Death Rate from Phthisis_,
+London, Dulau & Co., 1911.
+
+[6] Forel, August: _The Sexual Question_, p. 268.
+
+[7] Loc. cit. p. 251.
+
+[8] In this connection it is instructive to note from a Michigan state
+report, just off the press, that, among 4,917 insane individuals
+concerning whom satisfactory information was obtained, 65.4 per cent. "had
+among their ancestors or family such hereditary influences as insanity,
+apoplexy or paralysis, psychopathic abnormalities or alcoholism." See
+_Report of the Commission to Investigate the Extent of Feeble-mindedness,
+Epilepsy, Insanity and Other Conditions of Mental Defectiveness in
+Michigan_. Wynkoop Hollenbeck Crawford Co., State Printers, Lansing,
+Michigan, 1915.
+
+[9] _Feeble-mindedness; Its Causes and Consequences_, by Henry H. Goddard,
+The Macmillan Company, 1914.
+
+[10] _The Binet-Simon Measuring Scale for Intelligence_, by Henry H.
+Goddard, 1911. The Training School, Vineland, N. J. Price 15 cents.
+
+[11] "Tests for Mental Defects," by Howard A. Knox, _Journal of Heredity_,
+March, 1914. See also Knox: _Journal of the American Medical Association_,
+1914.
+
+[12] _The Individual Delinquent_, by William Healy, M. D. Little, Brown &
+Co., Boston.
+
+[13] _The Individual Delinquent_, by William Healy, M. D. Little, Brown &
+Co., Boston.
+
+[14] The Psycopathic Laboratory in connection with the Juvenile Court of
+Chicago.
+
+[15] See "The Foreign Born in the United States." _The National Geographic
+Magazine_, September, 1914.
+
+[16] See First Report of the Committee of the Eugenic Section of the
+American Breeders' Association, "On Immigration", _American Breeders'
+Magazine_, Vol. III, No. 4, 1912. Also Second Report of same, _The Journal
+of Heredity_, July, 1914.
+
+[17] "The Negro and His Health Problems," _Medical Record_, September 12,
+1912.
+
+[18] See D. S. Jordan, _The Human Harvest_, or V. L. Kellogg, _Eugenics
+and Militarism_.
+
+[19] For arguments indicating the superior eugenical fitness of college
+graduates see "Wellesley's Birth-Rate," by Roswell H. Johnson and Bertha
+Stutzman, _The Journal of Heredity_, June, 1915. See also, "Education and
+Race Suicide," by Robert J. Sprague, _ibid._, April, 1915.
+
+[20] Since the present manuscript went to press an excellent government
+report (_Insane and Feeble-Minded in Institutions in 1910_, Department of
+Commerce, Bureau of the Census, 1914, Washington, D. C.) has appeared. In
+it one finds the estimate that not over one-tenth of our feeble-minded are
+being cared for in special institutions.
+
+[21] For summaries of existing sterilization laws and statements of the
+issues involved see (1) _The Legal, Legislative, and Administrative
+Aspects of Sterilisation_, Bulletin 10B, February 3, 1914, Eugenics Record
+Office, Cold Spring Harbor, N. Y.; (2) _Sterilisation of Criminals_,
+Report of Committee H of the American Institute of Criminal Law and
+Criminology, Bulletin No. XV, September, 1914.
+
+
+
+
+Transcriber's Notes:
+
+Passages in italics are indicated by _italics_.
+
+Passages in bold are indicated by =bold=.
+
+Superscripted characters are indicated by ^{superscript}.
+
+Subscripted characters are indicated by _{subscript}.
+
+The original text contains a few letters with diacritical marks that are
+not represented in this text version.
+
+The original text contains male and female symbols. These are represented
+as [male] and [female].
+
+
+
+
+
+
+End of the Project Gutenberg EBook of Being Well-Born, by Michael F. Guyer
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