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+The Project Gutenberg eBook, Darwin, and After Darwin, Volume II (of 3),
+by George John Romanes
+
+
+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: Darwin, and After Darwin, Volume II (of 3)
+       Post-Darwinian Questions: Heredity and Utility
+
+
+Author: George John Romanes
+
+
+
+Release Date: October 15, 2011  [eBook #37759]
+
+Language: English
+
+Character set encoding: ISO-646-US (US-ASCII)
+
+
+***START OF THE PROJECT GUTENBERG EBOOK DARWIN, AND AFTER DARWIN, VOLUME
+II (OF 3)***
+
+
+E-text prepared by Marilynda Fraser-Cunliffe, L. N. Yaddanapudi, and the
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+
+
+
+
+
+DARWIN, AND AFTER DARWIN
+
+II
+
+Post-Darwinian Questions
+
+Heredity and Utility
+
+       *       *       *       *       *
+
+
+BY THE SAME AUTHOR.
+
+
+    DARWIN AND AFTER DARWIN. An Exposition of the Darwinian Theory and a
+        Discussion of Post-Darwinian Questions.
+          1. THE DARWINIAN THEORY. 460 pages. 125 illustrations. Cloth,
+              $2.00.
+          2. POST-DARWINIAN QUESTIONS. Edited by Prof. C. Lloyd Morgan.
+              338 pages. Cloth, $1.50. Both volumes together, $3.00 net.
+
+    AN EXAMINATION OF WEISMANNISM. 236 pages. Cloth, $1.00.
+
+    THOUGHTS ON RELIGION. Edited by Charles Gore, M.A., Canon of
+        Westminster. Second Edition. 184 pages. Cloth, gilt top, $1.25.
+
+
+THE OPEN COURT PUBLISHING COMPANY,
+324 DEARBORN STREET, CHICAGO.
+
+       *       *       *       *       *
+
+
+[Illustration: Frontispiece]
+
+
+DARWIN, AND AFTER DARWIN
+
+AN EXPOSITION OF THE DARWINIAN THEORY
+AND A DISCUSSION OF POST-DARWINIAN QUESTIONS
+
+by the Late
+
+GEORGE JOHN ROMANES, M.A., LL.D., F.R.S.
+Honorary Fellow of Gonville and Caius College, Cambridge
+
+II
+
+Post-Darwinian Questions
+Heredity and Utility
+
+FOURTH EDITION
+
+
+
+
+
+
+
+Chicago London
+The Open Court Publishing Company
+1916
+
+Chapter 1 Copyrighted by
+The Open Court Publishing Co.
+Chicago, Ill., 1895
+
+Printed in the
+United States of America
+
+
+
+
+PREFACE
+
+
+As its sub-title announces, the present volume is mainly devoted to a
+consideration of those Post-Darwinian Theories which involve fundamental
+questions of Heredity and Utility.
+
+As regards Heredity, I have restricted the discussion almost exclusively
+to Professor Weismann's views, partly because he is at present by far
+the most important writer upon this subject, and partly because his
+views with regard to it raise with most distinctness the issue which
+lies at the base of all Post-Darwinian speculation touching this
+subject--the issue as to the inheritance or non-inheritance of acquired
+characters.
+
+My examination of the Utility question may well seem to the general
+reader needlessly elaborate; for to such a reader it can scarcely fail
+to appear that the doctrine which I am assailing has been broken to
+fragments long before the criticism has drawn to a close. But from my
+previous experience of the hardness with which this fallacious doctrine
+dies, I do not deem it safe to allow even one fragment of it to remain,
+lest, hydra-like, it should re-develop into its former proportions. And
+I can scarcely think that naturalists who know the growing prevalence of
+the doctrine, and who may have followed the issues of previous
+discussions with regard to it, will accuse me of being more over-zealous
+in my attempt to make a full end thereof.
+
+One more remark. It is a misfortune attending the aim and scope of Part
+II that they bring me into frequent discord with one or other of the
+most eminent of Post-Darwinian writers--especially with Mr. Wallace. But
+such is the case only because the subject-matter of this volume is
+avowedly restricted to debateable topics, and because I choose those
+naturalists who are deservedly held in most esteem to act spokesmen on
+behalf of such Post-Darwinian views as appear to me doubtful or
+erroneous. Obviously, however, differences of opinion on particular
+points ought not to be taken as implying any failure on my part to
+recognize the general scientific authority of these men, or any
+inability to appreciate their labours in the varied fields of Biology.
+
+G. J. R.
+CHRIST CHURCH, OXFORD.
+
+
+
+
+NOTE
+
+Some time before his death Mr. Romanes decided to publish those sections
+of his work which deal with Heredity and Utility, as a separate volume,
+leaving Isolation and Physiological Selection for the third and
+concluding part of _Darwin, and after Darwin_.
+
+Most of the matter contained in this part was already in type, but was
+not finally corrected for the press. The alterations made therein are
+for the most part verbal.
+
+Chapter IV was type-written; in it, too, no alterations of any moment
+have been made.
+
+For Chapters V and VI there were notes and isolated paragraphs not yet
+arranged. I had promised during his life to write for Mr. Romanes
+Chapter V on the basis of these notes, extending it in such ways as
+seemed to be desirable. In that case it would have been revised and
+amended by the author and received his final sanction. Death annulled
+this friendly compact; and since, had I written the chapter myself, it
+could not receive that imprimatur which would have given its chief
+value, I have decided to arrange the material that passed into my hands
+without adding anything of importance thereto. The substance of Chapters
+V and VI is therefore entirely the author's: even the phraseology is
+his; the arrangement only is by another hand.
+
+Such parts of the Preface as more particularly refer to Isolation and
+Physiological Selection are reserved for publication in Part III. A year
+or more must elapse before that part will be ready for publication.
+
+Mr. F. Howard Collins has, as a kindly tribute to the memory of the
+author, read through the proofs. Messrs. F. Darwin, F. Galton, H.
+Seebohm, and others, have rendered incidental assistance. After much
+search I am unable to give the references to one or two passages.
+
+I have allowed a too flattering reference to myself to stand, in
+accordance with a particular injunction of Mr. Romanes given shortly
+before that sad day on which he died, leaving many to mourn the loss of
+a personal friend most bright, lovable, and generous-hearted, and
+thousands to regret that the hand which had written so much for them
+would write for them no more.
+
+C. LL. M.
+
+UNIVERSITY COLLEGE, BRISTOL,
+_April, 1894_.
+
+
+
+
+CONTENTS
+
+                                                                    PAGE
+CHAPTER I.
+INTRODUCTORY: THE DARWINISM OF DARWIN AND OF THE
+POST-DARWINIAN SCHOOLS                                                 1
+
+CHAPTER II.
+CHARACTERS AS HEREDITARY AND ACQUIRED (_Preliminary_)                 39
+
+CHAPTER III.
+CHARACTERS AS HEREDITARY AND ACQUIRED (_Continued_)
+    A. _Indirect evidence in favour of the Inheritance of Acquired
+        Characters_                                                   60
+    B. _Inherited effects of Use and of Disuse_                       95
+
+CHAPTER IV.
+CHARACTERS AS HEREDITARY AND ACQUIRED (_Continued_)
+    C. _Experimental evidence in favour of the Inheritance of Acquired
+        Characters_                                                  103
+
+CHAPTER V.
+CHARACTERS AS HEREDITARY AND ACQUIRED (_Continued_)
+    A. and B. _Direct and Indirect Evidence in favour of the
+        Non-inheritance of Acquired Characters_                      133
+
+    C. _Experimental Evidence as to the Non-inheritance of Acquired
+        Characters_                                                  142
+
+CHAPTER VI.
+CHARACTERS AS HEREDITARY AND ACQUIRED (_Conclusion_)                 150
+
+CHAPTER VII.
+CHARACTERS AS ADAPTIVE AND SPECIFIC                                  159
+
+CHAPTER VIII.
+CHARACTERS AS ADAPTIVE AND SPECIFIC (_Continued_)
+    I. _Climate_                                                     200
+    II. _Food_                                                       217
+    III. _Sexual Selection_                                          219
+    IV. _Isolation_                                                  223
+    V. _Laws of Growth_                                              226
+
+CHAPTER IX.
+CHARACTERS AS ADAPTIVE AND SPECIFIC (_Continued_)                    228
+
+CHAPTER X.
+CHARACTERS AS ADAPTIVE AND SPECIFIC (_Concluded_)                    251
+    SUMMARY                                                          274
+
+APPENDIX I. ON PANMIXIA                                              291
+
+APPENDIX II. ON CHARACTERS AS ADAPTIVE AND SPECIFIC                  307
+
+NOTE A TO PAGE 57                                                    333
+
+NOTE B TO PAGE 89                                                    337
+
+
+
+
+LIST OF ILLUSTRATIONS
+
+                                                                    PAGE
+
+Portrait of George John Romanes                           _Frontispiece_
+
+Diagram of Prof. Weismann's Theories                                  43
+
+FIG. 1. Guinea pigs, showing gangrene of ears due to injury of
+           restiform bodies                                          118
+
+FIG. 2. Old Irish Pig (after Richardson)                             188
+
+FIG. 3. Skulls of Niata Ox and of Wild White Ox                      192
+
+FIG. 4. Lower teeth of Orang (after Tomes)                           261
+
+
+
+
+CHAPTER I.
+
+INTRODUCTORY: THE DARWINISM OF DARWIN, AND OF THE POST-DARWINIAN
+SCHOOLS.
+
+
+It is desirable to open this volume of the treatise on _Darwin and after
+Darwin_ by taking a brief survey of the general theory of descent,
+first, as this was held by Darwin himself, and next, as it is now held
+by the several divergent schools of thought which have arisen since
+Darwin's death.
+
+The most important of the questions in debate is one which I have
+already had occasion to mention, while dealing, in historical order,
+with the objections that were brought against the theory of natural
+selection during the life-time of Darwin[1]. Here, however, we must
+consider it somewhat more in detail, and justify by quotation what was
+previously said regarding the very definite nature of his utterances
+upon the matter. This question is whether natural selection has been the
+sole, or but the main, cause of organic evolution.
+
+    [1] Part I, pp. 253-256.
+
+Must we regard survival of the fittest as the one and only principle
+which has been concerned in the progressive modification of living
+forms, or are we to suppose that this great and leading principle has
+been assisted by other and subordinate principles, without the
+co-operation of which the results, as presented in the animal and
+vegetable kingdoms, could not have been effected? Now Darwin's answer to
+this question was distinct and unequivocal. He stoutly resisted the
+doctrine that natural selection was to be regarded as the only cause of
+organic evolution. On the other hand, this opinion was--and still
+continues to be--persistently maintained by Mr. Wallace; and it
+constitutes the source of all the differences between his views and
+those of Darwin. Moreover, up to the time of Darwin's death, Mr. Wallace
+was absolutely alone in maintaining this opinion: the whole body of
+scientific thought throughout the world being against him; for it was
+deemed improbable that, in the enormously complex and endlessly varied
+processes of organic evolution, only a single principle should be
+everywhere and exclusively concerned[2]. But since Darwin's death there
+has been a great revolution of biological thought in favour of Mr.
+Wallace's opinion. And the reason for this revolution has been, that his
+doctrine of natural selection as the sole cause of organic evolution has
+received the corroborative support of Professor Weismann's theory of
+heredity--which has been more or less cordially embraced by a certain
+section of evolutionists, and which appears to carry the doctrine in
+question as a logical corollary, so far, at all events, as adaptive
+structures are concerned.
+
+    [2] _Contributions to the Theory of Natural Selection_, p. 47.
+
+Now in this opening chapter we shall have to do merely with a setting
+forth of Darwin's opinion: we are not considering how far that opinion
+ought to be regarded as having been in any measure displaced by the
+results of more recent progress. Such, then, being the only matter which
+here concerns us, I will supply a few brief quotations, to show how
+unequivocally Darwin has stated his views. First, we may take what he
+says upon the "Lamarckian factors[3];" and next we may consider what he
+says with regard to other factors, or, in general, upon natural
+selection not being the sole cause of organic evolution.
+
+    [3] So far as we shall be concerned with them throughout this
+        treatise, the "Lamarckian factors" consist in the supposed
+        transmission of acquired characters, whether the latter be due
+        to the direct influence of external conditions of life on the
+        one hand, or to the inherited effects of use and disuse on the
+        other. For the phrase "inherited effects of use and disuse," I
+        shall frequently employ the term "use-inheritance," which has
+        been coined by Mr. Platt Ball as a more convenient expression.
+
+     "Changed habits produce an inherited effect, as in the period of
+     the flowering of plants when transported from one climate to
+     another. With animals the increased use or disuse of parts has had
+     a more marked influence[4]."
+
+    [4] _Origin of Species_, 6th ed. p. 8.
+
+     "There can be no doubt, from the facts given in this chapter, that
+     extremely slight changes in the conditions of life sometimes,
+     probably often, act in a definite manner on our domesticated
+     productions; and, as the action of changed conditions in causing
+     indefinite variability is accumulative, so it may be with their
+     definite action. Hence considerable and definite modifications of
+     structure probably follow from altered conditions acting during
+     long series of generations[5]."
+
+    [5] _Variation_ &c. 2nd ed. ii. p. 280.
+
+     "How, again, can we explain the inherited effects of the use and
+     disuse of particular organs? The domesticated duck flies less and
+     walks more than the wild duck, and its limb bones have become
+     diminished and increased in a corresponding manner in comparison
+     with those of the wild duck. A horse is trained to certain paces,
+     and the colt inherits similar consensual movements. The
+     domesticated rabbit becomes tame from close confinement; the dog,
+     intelligent from associating with man; the retriever is taught to
+     fetch and carry; and these mental endowments and bodily powers are
+     all inherited. Nothing in the whole circuit of physiology is more
+     wonderful. How can the use or disuse of a particular limb or of the
+     brain affect a small aggregate of reproductive cells, seated in a
+     distant part of the body, in such a manner that the being developed
+     from these cells inherits the characters of either one or both
+     parents?... In the chapters devoted to inheritance, it was shown
+     that a multitude of newly acquired characters, whether injurious or
+     beneficial, whether of the lowest or highest vital importance, are
+     often faithfully transmitted[6]."
+
+    [6] _Variation_ &c. ii. p. 367.
+
+     "When discussing special cases, Mr. Mivart passes over the effects
+     of the increased use and disuse of parts, which I have always
+     maintained to be highly important, and have treated in my
+     'Variation under Domestication' at greater length than, as I
+     believe, any other writer[7]."
+
+    [7] _Origin of Species_, p. 176.
+
+So much for the matured opinion of Darwin touching the validity of the
+theory of use-inheritance. Turning now to his opinion on the question
+whether or not there are yet any further factors concerned in the
+process of organic evolution, I think it will be sufficient to quote a
+single passage from the _Origin of Species_. The first paragraph of the
+"Conclusion" is devoted to a _resume_ of his views upon this matter, and
+consists of the following most emphatic words.
+
+     "I have now recapitulated the facts and considerations which have
+     thoroughly convinced me that species have been modified, during a
+     long course of descent. This has been effected chiefly through the
+     natural selection of numerous successive, slight, favourable
+     variations; aided in an important manner by the inherited effects
+     of the use and disuse of parts; and in an unimportant manner, that
+     is in relation to adaptive structures, whether past or present, by
+     the direct action of external conditions, and by variations which
+     seem to us in our ignorance to arise spontaneously. It appears that
+     I formerly underrated the frequency and value of these latter forms
+     of variation, as leading to permanent modifications of structure
+     independently of natural selection. But as my conclusions have
+     lately been much misrepresented, and it has been stated that I
+     attribute the modification of species exclusively to natural
+     selection, I may be permitted to remark that in the first edition
+     of this work, and subsequently, I placed in a most conspicuous
+     position--namely, at the close of the Introduction--the following
+     words: 'I am convinced that natural selection has been the main,
+     but not the exclusive means of modification.' This has been of no
+     avail. Great is the power of steady misrepresentation; but the
+     history of science shows that fortunately this power does not long
+     endure."
+
+In the whole range of Darwin's writings there cannot be found a passage
+so strongly worded as this: it presents the only note of bitterness in
+all the thousands of pages which he has published. Therefore I do not
+think it is necessary to supply any further quotations for the purpose
+of proving the state of his opinion upon the point in question. But, be
+it carefully noted, from this great or radical difference of opinion
+between the joint originators of the theory of natural selection, all
+their other differences of opinion arise; and seeing that since the
+death of Darwin a large number of naturalists have gone over to the side
+of Wallace, it seems desirable here to state categorically what these
+other or sequent points of difference are. Without at present discussing
+them, therefore, I will merely set them out in a tabular form, in order
+that a clear perception may be gained of their logical connexion with
+this primary point of difference.
+
+     |_The Theory of Natural      |_The theory of Natural      |
+     |Selection according to      |Selection according to      |
+     |Darwin._                    |Wallace._                   |
+     |                            |                            |
+     |Natural Selection has been  |Natural Selection has been  |
+     |the main means of           |the sole means of           |
+     |modification, not excepting |modification, excepting in  |
+     |the case of Man.            |the case of Man.            |
+     |                            |                            |
+     |(_a_) Therefore it is a     |(_a_) Therefore it is       |
+     |question of evidence        |antecedently impossible     |
+     |whether the Lamarckian      |that the Lamarckian factors |
+     |factors have co-operated.   |can have co-operated.       |
+     |                            |                            |
+     |(_b_) Neither all species,  |(_b_) Not only all species, |
+     |nor, _a fortiori_, all      |but all specific            |
+     |specific characters, have   |characters, must            |
+     |been due to natural         |necessarily have been due   |
+     |selection.                  |to natural selection.       |
+     |                            |                            |
+     |(_c_) Thus the principle of |(_c_) Thus the principle of |
+     |Utility is not of universal |Utility must necessarily be |
+     |application, even where     |of universal application,   |
+     |species are concerned.      |where species are           |
+     |                            |concerned.                  |
+     |                            |                            |
+     |(_d_) Thus, also, the       |(_d_) Thus, also, the       |
+     |suggestion as to Sexual     |suggestion as to Sexual     |
+     |Selection, or any other     |Selection, or of any other  |
+     |supplementary cause of      |supplementary cause of      |
+     |modification, may be        |modification, must be ruled |
+     |entertained; and, as in the |out; and, as in the case of |
+     |case of the Lamarckian      |the Lamarckian factors,     |
+     |factors, it is a question   |their co-operation deemed   |
+     |of evidence whether, or how |impossible.                 |
+     |far, they have co-operated. |                            |
+     |                            |                            |
+     |(_e_) No detriment arises   |(_e_) The possibility--and, |
+     |to the theory of natural    |_a fortiori_ the            |
+     |selection as a theory of    |probability--of any         |
+     |the origin of species by    |supplementary factors       |
+     |entertaining the            |cannot be entertained       |
+     |possibility, or the         |without serious detriment   |
+     |probability, of             |to the theory of natural    |
+     |supplementary factors.      |selection, as a theory of   |
+     |                            |the origin of species.      |
+     |                            |                            |
+     |(_f_) Cross-sterility in    |(_f_) Cross-sterility in    |
+     |species cannot possibly be  |species is probably due to  |
+     |due to natural selection.   |natural selection[8].       |
+
+    [8] This, to the best of my judgement, is the fairest extract that I
+        can give of Mr. Wallace's most recently published opinions on
+        the points in question. [In particular as regards (_a_) see
+        _Darwinism_ pp. 435-6.] But with regard to some of them, his
+        expression of opinion is not always consistent, as we shall find
+        in detail later on. Besides, I am here taking Mr. Wallace as
+        representative of the Neo-Darwinian school, one or other
+        prominent member of which has given emphatic expression to each
+        of the above propositions.
+
+As it will be my endeavour in the ensuing chapters to consider the
+rights and the wrongs of these antithetical propositions, I may reserve
+further quotations from Darwin's works, which will show that the above
+is a correct epitome of his views as contrasted with those of Wallace
+and the Neo-Darwinian school of Weismann. But here, where the object is
+merely a statement of Darwin's theory touching the points in which it
+differs from those of Wallace and Weismann, it will be sufficient to set
+forth these points of difference in another and somewhat fuller form. So
+far then as we are at present concerned, the following are the matters
+of doctrine which have been clearly, emphatically, repeatedly, and
+uniformly expressed throughout the whole range of Darwin's writings.
+
+1. That natural selection has been the main means of modification.
+
+2. That, nevertheless, it has not been the only means; but has been
+supplemented or assisted by the co-operation of other causes.
+
+3. That the most "important" of these other causes has been the
+inheritance of functionally-produced modifications (use-inheritance);
+but this only because the transmission of such modifications to progeny
+must always have had immediate reference to _adaptive_ ends, as
+distinguished from merely useless change.
+
+4. That there are sundry other causes which lead to merely useless
+change--in particular, "the direct action of external conditions, and
+variations which seem to us in our ignorance to arise spontaneously."
+
+5. Hence, that the "principle of utility," far from being of universal
+occurrence in the sphere of animate nature, is only of what may be
+termed highly general occurrence; and, therefore, that certain other
+advocates of the theory of natural selection were mistaken in
+representing the universality of this principle as following by way of
+necessary consequence from that theory.
+
+6. Cross-sterility in species cannot possibly be due to natural
+selection; but everywhere arises as a result of some physiological
+change having exclusive reference to the sexual system--a change which
+is probably everywhere due to the same cause, although what this cause
+could be Darwin was confessedly unable to suggest.
+
+Such, then, was the theory of evolution as held by Darwin, so far as the
+points at present before us are concerned. And, it may now be added,
+that the longer he lived, and the more he pondered these points, the
+less exclusive was the _role_ which he assigned to natural selection,
+and the more importance did he attribute to the supplementary factors
+above named. This admits of being easily demonstrated by comparing
+successive editions of his works; a method adopted by Mr. Herbert
+Spencer in his essay on the _Factors of Organic Evolution_.
+
+My object in thus clearly defining Darwin's attitude regarding these
+sundry points is twofold.
+
+In the first place, with regard to merely historical accuracy, it
+appears to me undesirable that naturalists should endeavour to hide
+certain parts of Darwin's teaching, and give undue prominence to others.
+In the second place, it appears to me still more undesirable that this
+should be done--as it usually is done--for the purpose of making it
+appear that Darwin's teaching did not really differ very much from that
+of Wallace and Weismann on the important points in question. I myself
+believe that Darwin's judgement with regard to all these points will
+eventually prove more sound and accurate than that of any of the recent
+would-be improvers upon his system; but even apart from this opinion of
+my own it is undesirable that Darwin's views should be misrepresented,
+whether the misrepresentation be due to any unfavourable bias against
+one side of his teaching, or to sheer carelessness in the reading of his
+books. Yet the new school of evolutionists, to which allusion has now so
+frequently been made, speak of their own modifications of Darwin's
+teaching as "pure Darwinism," in contradistinction to what they call
+"Lamarckism." In other words, they represent the principles of
+"Darwinism" as standing in some kind of opposition to those of
+"Lamarckism": the Darwinian principle of natural selection, they think,
+is in itself enough to account for all the facts of adaptation in
+organic nature. Therefore they are eager to dispense with the Lamarckian
+principle of the inherited effects of use and disuse, together with the
+direct influence of external conditions of life, and all or any other
+causes of modification which either have been, or in the future may
+possibly be, suggested. Now, of course, there is no reason why any one
+should not hold these or any other opinions to which his own
+independent study of natural science may lead him; but it appears to me
+that there is the very strongest reason why any one who deviates from
+the carefully formed opinions of such a man as Darwin, should above all
+things be careful to be absolutely fair in his representations of them;
+he should be scrupulously jealous, so to speak, of not letting it appear
+that he is unjustifiably throwing over his own opinions the authority of
+Darwin's name.
+
+But in the present case, as we have seen, not only do the Neo-Darwinians
+strain the teachings of Darwin; they positively reverse those
+teachings--representing as anti-Darwinian the whole of one side of
+Darwin's system, and calling those who continue to accept that system in
+its entirety by the name "Lamarckians." I know it is sometimes said by
+members of this school, that in his utilization of Lamarckian principles
+as accessory to his own, Darwin was actuated by motives of "generosity."
+But a more preposterous suggestion could not well be made. We may
+fearlessly challenge any one who speaks or writes in such a way, to show
+any other instance where Darwin's great generosity of disposition had
+the effect of influencing by one hair's breadth his still greater
+loyalty to truth. Moreover, and with special regard to this particular
+case, I would point out that in no one of his many allusions to, and
+often lengthy discussions of, these so-called Lamarckian principles,
+does he ever once introduce the name of Lamarck; while, on the other
+hand, in the only places where he does so--whether in his books or in
+his now published letters--he does so in order to express an almost
+contemptuous dissatisfaction, and a total absence of obligation. Hence,
+having regard to the "generosity" with which he always acknowledged
+obligations, there can be no reasonable doubt that Darwin was not in the
+smallest degree influenced by the speculative writings of Lamarck; or
+that, even if Lamarck had never lived, the _Origin of Species_ would
+have differed in any single particular from the form in which it now
+stands. Finally, it must not be forgotten that Darwin's acceptance of
+the theory of use-inheritance was vitally essential to his theory of
+Pangenesis--that "beloved child" over which he had "thought so much as
+to have lost all power of judging it[9]."
+
+    [9] _Life and Letters_, vol. iii. pp. 72 and 75.
+
+What has just been said touching the relations between Darwin's theory
+and that of Lamarck, applies with equal force to the relations between
+Darwin's theory and any other theory appertaining to evolution which has
+already been, or may hereafter be propounded. Yet so greatly have some
+of the Neo-Darwinians misunderstood the teachings of Darwin, that they
+represent as "Darwinian heresy" any suggestions in the way of factors
+"supplementary to," or "co-operative with" natural selection. Of course,
+if these naturalists were to avow themselves followers of Wallace,
+instead of followers of Darwin, they would be perfectly justified in
+repudiating any such suggestions as, _ipso facto_ heretical. But, as we
+have now seen, through all his life Darwin differed from Wallace with
+regard to this very point; and therefore, unlike Wallace, he was always
+ready to entertain "additional suggestions" regarding the causes of
+organic evolution--several of which, indeed, he himself supplied. Hence
+we arrive at this curious state of matters. Those biologists who of late
+years have been led by Weismann to adopt the opinions of Wallace,
+represent as anti-Darwinian the opinions of other biologists who still
+adhere to the unadulterated doctrines of Darwin. Weismann's _Essays on
+Heredity_ (which argue that natural selection is the only possible cause
+of adaptive modification) and Wallace's work on _Darwinism_ (which in
+all the respects where any charge of "heresy" is concerned directly
+contradicts the doctrine of Darwin)--these are the writings which are
+now habitually represented by the Neo-Darwinians as setting forth the
+views of Darwin in their "pure" form. The result is that, both in
+conversation and in the press, we habitually meet with complete
+inversions of the truth, which show the state of confusion into which a
+very simple matter has been wrought by the eagerness of certain
+naturalists to identify the views of Darwin with those of Wallace and
+Weismann. But we may easily escape this confusion, if we remember that
+wherever in the writings of these naturalists there occur such phrases
+as "pure Darwinism" we are to understand pure _Wallaceism_, or the pure
+theory of natural selection to the exclusion of any supplementary
+theory. Therefore it is that for the sake of clearness I coined, several
+years ago, the terms "Neo-Darwinian" and "Ultra-Darwinian" whereby to
+designate the school in question.
+
+       *       *       *       *       *
+
+So much, then, for the Darwinism of Darwin, as contrasted with the
+Darwinism of Wallace, or, what is the same thing, of the Neo-Darwinian
+school of Weismann. Next we may turn, by way of antithesis, to the
+so-called "Neo-Lamarckian" school of the United States. For, by a
+curious irony of fate, while the Neo-Darwinian school is in Europe
+seeking to out-Darwin Darwin by assigning an exclusive prerogative to
+natural selection in both kingdoms of animate nature, the Neo-Lamarckian
+school is in America endeavouring to reform Darwinism in precisely the
+opposite direction--viz. by transferring the sovereignty from natural
+selection to the principles of Lamarck. Without denying to natural
+selection a more or less important part in the process of organic
+evolution, members of this school believe that much greater importance
+ought to be assigned to the inherited effects of use and disuse than was
+assigned to these agencies by Darwin. Perhaps this noteworthy state of
+affairs, within a decade of Darwin's death, may lead us to anticipate
+that his judgement--standing, as it does, between these two
+extremes--will eventually prove the most accurate of all, with respect
+to the relative importance of these factors of evolution. But, be this
+as it may, I must now offer a few remarks upon the present position of
+the matter.
+
+In the first place, to any one who (with Darwin and against Weismann)
+admits not only the abstract possibility, but an actual working, of the
+Lamarckian factors, it becomes difficult to determine, even
+approximately, the degrees of value which ought to be ascribed to them
+and to natural selection respectively. For, since the results are in
+both cases identical in kind (as, adaptive changes of organic types),
+where both sets of causes are supposed to be in operation together, we
+have no means of estimating the relative shares which they have had in
+bringing about these results. Of course there are large numbers of cases
+where it cannot possibly be supposed that the Lamarckian factors have
+taken any part at all in producing the observed effects; and therefore
+in such cases there is almost full agreement among evolutionists in
+theoretically ascribing such effects to the exclusive agency of natural
+selection. Of such, for instance, are the facts of protective colouring,
+of mimicry, of the growth of parts which, although _useful_, are never
+_active_ (e.g. shells of mollusks, hard coverings of seeds), and so on.
+But in the majority of cases where adaptive structures are concerned,
+there is no means of discriminating between the influences of the
+Lamarckian and the Darwinian factors. Consequently, if by the
+Neo-Lamarckian school we understand all those naturalists who assign any
+higher importance to the Lamarckian factors than was assigned to them by
+Darwin, we may observe that members of this school differ very greatly
+among themselves as to the degree of importance that ought to be
+assigned. On the one hand we have, in Europe, Giard, Perrier, and Eimer,
+who stand nearer to Darwin than do a number of the American
+representatives--of whom the most prominent are Cope, Osborn, Packard,
+Hyatt, Brooks, Ryder, and Dall. The most extreme of these is Professor
+Cope, whose collection of essays entitled _The Origin of the Fittest_,
+as well as his more recent and elaborate monograph on _The Development
+of the Hard Parts of the Mammalia_, represent what appears even to some
+other members of his school an extravagant estimate of the importance
+of Lamarckian principles.
+
+But the most novel, and in many respects the most remarkable school of
+what may be termed Anti-selectionists is one which is now (1894) rapidly
+increasing both in numbers and in weight, not only in the New World, but
+also in Germany, and to a lesser extent, in Great Britain.
+
+This school, without being either Lamarckian or Darwinian (for its
+individual members differ widely from one another in these respects)
+maintains a principle which it deems of more importance than either
+use-inheritance or natural selection. This principle it calls
+Self-adaptation. It is chiefly botanists who constitute this school, and
+its principal representatives, in regard to authority, are Sachs,
+Pfeffer and Henslow.
+
+Apart from topics which are to be dealt with in subsequent chapters, the
+only matters of much importance which have been raised in the
+Post-Darwinian period are those presented by the theories of Geddes,
+Cope, Hyatt, and others, and certain more or less novel ideas set forth
+in Wallace's _Darwinism_.
+
+Mr. Geddes has propounded a new theory of the origin of species, which
+in his judgement supersedes to a large extent the theory of natural
+selection. He has also, in conjunction with Mr. Thomson, propounded a
+theory of the origin of sex. For my own part, I cannot see that these
+views embody any principles or suggestions of a sufficiently definite
+kind to constitute them theories at all. In this respect the views of
+Mr. Geddes resemble those of Professors Cope, Hyatt, and others, on what
+they term "the law of acceleration and retardation." In all these
+cases, so far as I can see, the so-called explanations are not in fact
+any explanations; but either a mere re-statement of the facts, or else
+an enunciation of more or less meaningless propositions. Thus, when it
+is said that the evolution of any given type has been due to the
+"acceleration of growth-force" with respect to some structures, and the
+"retardation of growth-force" with respect to others, it appears evident
+that we have not any real explanation in terms of causality; we have
+only the form of an explanation in the terms of a proposition. All that
+has been done is to express the fact of evolution in somewhat obscure
+phraseology, since the very thing we want to know about this fact
+is--What are the causes of it as a fact, or the reasons which have led
+to the increase of some of the parts of any given type, and the
+concomitant decrease of others? It is merely the facts themselves that
+are again presented by saying that the development has been in the one
+case accelerated, while in the other it has been retarded[10].
+
+    [10] Take, for example, the following, which is a fair epitome of
+         the whole:--"I believe that this is the simplest mode of
+         stating and explaining the law of variation; that some forms
+         acquire something which their parents did not possess; and that
+         those which acquire something additional have to pass through
+         more numerous stages than their ancestors; and those which lose
+         something pass through fewer stages than their ancestors; and
+         these processes are expressed by the terms 'acceleration' and
+         'retardation'" (_Origin of the Fittest_, pp. 125, 226, and
+         297). Even if this be "the simplest mode of _stating_ the law
+         of variation," it obviously does nothing in the way of
+         _explaining_ the law.
+
+So much for what may be termed this New World theory of the origin of
+species: it is a mere re-statement of the facts. Mr. Geddes' theory, on
+the other hand, although more than a mere re-statement of the facts,
+appears to me too vague to be of any explanatory service. His view is
+that organic evolution has everywhere depended upon an antagonism,
+within the limits of the same organism, between the processes of
+nutrition and those of reproduction. But although he is thus able
+hypothetically to explain certain facts--such as the shortening of a
+flower-spike into a composite flower--the suggestion is obviously
+inadequate to meet, even hypothetically, most of the facts of organic
+evolution, and especially the development of _adaptive_ structures.
+Therefore, it seems to me, we may dismiss it even as regards the
+comparatively few facts which it might conceivably explain--seeing that
+these same facts may be equally well explained by the causes which are
+already known to operate in other cases. For it is the business of
+natural selection to ensure that there shall nowhere be any needless
+expenditure of vital energy, and, consequently, that everywhere the
+balance between nutrition and reproduction shall be most profitably
+adjusted.
+
+Similarly with respect to the theory of the _Origin of Sex_, I am unable
+to perceive even this much of scientific relevancy. As stated by its
+authors the theory is, that the female is everywhere "anabolic," as
+compared with the male, which is "katabolic." By anabolic is meant
+comparative inactivity of protoplasmic change due to a nutritive winding
+up of molecular constitution, while by katabolic is meant the opposite
+condition of comparative activity due to a dynamic running down of
+molecular constitution. How, then, can the _origin_ of sex be explained,
+or the _causes_ which led to the differentiation of the sexes be shown
+by saying that the one sex is anabolic and the other katabolic? In so
+far as these verbal statements serve to express what is said to be a
+general fact--namely, that the female sexual elements are less mobile
+than the male--they merely serve to re-state this general fact in
+terminology which, as the authors themselves observe, is "unquestionably
+ugly." But in so far as any question of _origin_ or _causality_ is
+concerned, it appears to me that there is absolutely no meaning in such
+statements. They belong to the order of merely formal explanations, as
+when it is said that the toxic qualities of morphia are due to this drug
+possessing a soporific character.
+
+Much the same, in my opinion, has to be said of the Rev. G. Henslow's
+theory of the origin of species by what he terms "self-adaptation."
+Stated briefly his view is that there is no sufficient evidence of
+natural selection as a _vera causa_, while there is very abundant
+evidence of adjustments occurring without it, first in individual
+organisms, and next, by inheritance of acquired characters, in species.
+Now, much that he says in criticism of the selection theory is of
+considerable interest as such; but when we pass from the critical to the
+constructive portions of his books and papers, we again meet with the
+want of clearness in thought between a statement of facts in terms of a
+proposition, and an explanation of them in those of causality. Indeed, I
+understand from private correspondence, that Mr. Henslow himself admits
+the validity of this criticism; for in answer to my questions,--"How
+does Self-adaptation work in each case, and why should protoplasm be
+able to _adapt itself_ into the millions of diverse mechanisms in
+nature?"--he writes. "Self-adaptation does not profess to be a _vera
+causa_ at all; for the true causes of variation can only be found in the
+answer to your [above] questions, and I must say at once, _these
+questions cannot be answered_." That is, they cannot be answered on the
+hypothesis of self-adaptation, which is therefore a statement of the
+facts of adaptation as distinguished from an explanation of them.
+Nevertheless, two things have here to be noted. In the first place, the
+statement of facts which Mr. Henslow has collected is of considerable
+theoretical importance as tending to show that there are probably causes
+of an internal kind (i. e. other than natural selection) which have been
+largely concerned in the adaptive modification of plants. And, in the
+second place, it is not quite true that the theory of self-adaptation
+is, as its author says in the sentences above quoted, a mere statement
+of the facts of adaptation, without any attempt at explaining their
+causes. For in his published words he does attempt to do so[11]. And,
+although I think his attempt is a conspicuous failure, I ought in
+fairness to give examples of it. His books are almost exclusively
+concerned in an application of his theory to the mechanisms of flowers
+for securing their own fertilization. These mechanisms he ascribes, in
+the case of entomophylous flowers, to the "thrusts," "strains," and
+other "irritations" supplied to the flowers by their insect visitors,
+and consequent "reactions" of the vegetable "protoplasm." But no attempt
+is made to show why these "reactions" should be of an _adaptive_ kind,
+so as to build up the millions of diverse and often elaborate mechanisms
+in question--including not only forms and movements, but also colours,
+odours, and secretions. For my own part I confess that, even granting to
+an ultra-Lamarckian extent the inheritance of acquired characters, I
+could conceive of "self-adaptation" alone producing all such innumerable
+and diversified adjustments only after seeing, with Cardinal Newman, an
+angel in every flower. Yet Mr. Henslow somewhat vehemently repudiates
+any association between his theory and that of teleology.
+
+    [11] _Floral Structures_ (Internat. Sc. Ser. lxiv. 1888): _The
+         Making of Flowers_ (Romance of Science Ser. 1891); and Linn.
+         Soc. Papers 1893-4.
+
+On the whole, then, I regard all the works which are here classed
+together (those by Cope, Geddes, and Henslow), as resembling one another
+both in their merits and defects. Their common merits lie in their
+erudition and much of their criticism, while their common defects
+consist on the one hand in not sufficiently distinguishing between mere
+statements and real explanations of facts, and, on the other, in not
+perceiving that the theories severally suggested as substitutes for that
+of natural selection, even if they be granted true, could be accepted
+only as co-operative factors, and by no stretch of logic as substitutes.
+
+       *       *       *       *       *
+
+Turning now to Mr. Wallace's work on _Darwinism_, we have to notice, in
+the first place, that its doctrine differs from "Darwinism" in regard to
+the important dogma which it is the leading purpose of that work to
+sustain--namely, that "the law of utility" is, to all intents and
+purposes, universal, with the result that natural selection is virtually
+the only cause of organic evolution. I say "to all intents and
+purposes," or "virtually," because Mr. Wallace does not expressly
+maintain the abstract impossibility of laws and causes other than those
+of utility and natural selection; indeed, at the end of his treatise, he
+quotes with approval Darwin's judgement, that "natural selection has
+been the most important, but not the exclusive means of modification."
+Nevertheless, as he nowhere recognizes any other law or cause of
+adaptive evolution[12], he practically concludes that, on inductive or
+empirical grounds, there _is_ no such other law or cause to be
+entertained--until we come to the particular case of the human mind. But
+even in making this one particular exception--or in representing that
+some other law than that of utility, and some other cause than that of
+natural selection, must have been concerned in evolving the mind of
+man--he is not approximating his system to that of Darwin. On the
+contrary, he is but increasing the divergence, for, of course, it was
+Darwin's view that no such exception could be legitimately drawn with
+respect to this particular instance. And if, as I understand must be the
+case, his expressed agreement with Darwin touching natural selection not
+being the only cause of adaptive evolution has reference to this point,
+the quotation is singularly inapt.
+
+    [12] "The law of correlation," and the "laws of growth," he does
+         recognize; and shows that they furnish an explanation of the
+         origin of many characters, which cannot be brought under "the
+         law of utility."
+
+Looking, then, to these serious differences between his own doctrine of
+evolution--both organic and mental--and that of Darwin, I cannot think
+that Mr. Wallace has chosen a suitable title for his book; because, in
+view of the points just mentioned, it is unquestionable that _Darwinism_
+differs more widely from the _Origin of Species_ than does the _Origin
+of Species_ from the writings of the Neo-Lamarckians. But, passing over
+this merely nominal matter, a few words ought to be added on the very
+material question regarding the human mind. In subsequent chapters the
+more general question, or that which relates to the range of utility and
+natural selection elsewhere will be fully considered.
+
+Mr. Wallace says,--
+
+     "The immense interest that attaches to the origin of the human
+     race, and the amount of misconception which prevails regarding the
+     essential teachings of Darwin's theory on the question, as well as
+     regarding my own special views upon it, induce me to devote a final
+     chapter to its discussion."
+
+Now I am not aware that there is any misconception in any quarter as to
+the essential teachings of Darwin's theory on this question. Surely it
+is rather the case that there is a very general and very complete
+understanding on this point, both by the friends and the foes of
+Darwin's theory--so much so, indeed, that it is about the only point of
+similar import in all Darwin's writings of which this can be said. Mr.
+Wallace's "special views" on the other hand are, briefly stated, that
+certain features, both of the morphology and the psychology of man, are
+inexplicable by natural selection--or indeed by any other cause of the
+kind ordinarily understood by the term natural: they can be explained
+only by supposing "the intervention of some distinct individual
+intelligence," which, however, need not necessarily be "one Supreme
+Intelligence," but some other order of Personality standing anywhere in
+"an infinite chasm between man and the Great Mind of the universe[13]."
+Let us consider separately the corporeal and the mental peculiarities
+which are given as justifying this important conclusion.
+
+    [13] _Natural Selection and Tropical Nature_, p. 205; 1891.
+
+The bodily peculiarities are the feet, the hands, the brain, the voice,
+and the naked skin.
+
+As regards the feet Mr. Wallace writes, "It is difficult to see why the
+prehensile power [of the great toe] should have been taken away,"
+because, although "it may not be compatible with perfectly easy erect
+locomotion," "how can we conceive that early man, _as an animal_, gained
+anything by purely erect locomotion[14]?" But surely it is not difficult
+to conceive this. In the proportion that our simian progenitors ceased
+to be arboreal in their habits (and there may well have been very good
+utilitarian reasons for such a change of habitat, analogous to those
+which are known to have occurred in the phylogenesis of countless other
+animals), it would clearly have been of advantage to them that their
+already semi-erect attitude should have been rendered more and more
+erect. To name one among several probabilities, the more erect the
+attitude, and the more habitually it was assumed, the more would the
+hands have been liberated for all the important purposes of
+manipulation. The principle of the physiological division of labour
+would thus have come more and more into play: natural selection would
+therefore have rendered the upper extremities more and more suited to
+the execution of these purposes, while at the same time it would have
+more and more adapted the lower ones to discharging the sole function of
+locomotion. For my own part, I cannot perceive any difficulty about
+this: in fact, there is an admirable repetition of the process in the
+ontogeny of our own children[15].
+
+    [14] _Ibid._ pp. 197-8.
+
+    [15] For an excellent discussion on the ontogeny of the child in
+         this connexion, see _Some Laws of Heredity_, by Mr. S. S.
+         Buckman, pp. 290, _et seq._ (Proc. Cotteswold Nat. Field Club,
+         vol. x. p. 3, 1892).
+
+Next, with regard to the hand, Mr. Wallace says, that it "contains
+latent capacities which are unused by savages, and must have been even
+less used by palaeolithic man and his still ruder predecessors." Thus,
+"it has all the appearance of an organ prepared for the use of civilized
+man[16]." Even if this be true, however, it would surely be a dangerous
+argument to rely upon, seeing that we cannot say of how much importance
+it may have been for early man--or even apes--to have had their power of
+manipulation progressively improved. But is the statement true? It
+appears to me that if Mr. Wallace had endeavoured to imitate the
+manufactures that were practised by "palaeolithic man," he would have
+found the very best of reasons for cancelling his statement. For it is
+an extremely difficult thing to chip a flint into the form of an
+arrow-head: when made, the suitable attachment of it to a previously
+prepared arrow is no easy matter: neither a bow nor a bow-string could
+have been constructed by hands of much less perfection than our own: and
+the slaying of game with the whole apparatus, when it has been
+constructed, requires a manual dexterity which we may be perfectly
+certain that Mr. Wallace--unless he has practised the art from
+boyhood--does not possess.
+
+    [16] _loc. cit._ p. 198.
+
+So it is with his similar argument that the human voice is more
+"powerful," more "flexible," and presents a greater "range" and
+"sweetness" than the needs of savage life can be held to require. The
+futility of this argument is self-evident as regards "power." And
+although its weakness is not so obvious with respect to the other three
+qualities which are named, need we go further than the closely analogous
+case of certain birds to show the precariousness of arguing from such
+facts of organic nature to the special operation of "a superior
+intelligence"? I can hardly suppose that Mr. Wallace will invoke any
+such agency for the purpose of explaining the "latent capacities" of the
+voice of a parrot. Yet, in many respects, these are even more wonderful
+than those of the human voice, albeit in a wild state they are "never
+required or used[17]."
+
+    [17] For a discussion of this remarkable case, see _Mental Evolution
+         in Animals_, pp. 222-3. It appears to me that if Mr. Wallace's
+         argument from the "latent capacities of the voice of Man" is
+         good for anything, _a fortiori_ it must be taken to prove that,
+         in the case of the Parrot, "the organ has been prepared in
+         anticipation" of the amusement which the cultivation of its
+         latent capacities arouses in "civilized man."
+
+Once more, with regard to the naked skin, it seems sufficient to quote
+the following passage from the first edition of the _Descent of Man_.
+
+     "The Rev. T. R. Stebbing, in commenting on this view, remarks, that
+     had Mr. Wallace 'employed his usual ingenuity on the question of
+     man's hairless skin, he might have seen the possibility of its
+     selection through its superior beauty, or the health attaching to
+     superior cleanliness. At any rate it is surprising that he should
+     picture to himself a superior intelligence plucking the hair from
+     the backs of savage men (to whom, according to his own account, it
+     would have been useful and beneficial), in order that the
+     descendants of the poor shorn wretches might, after many deaths
+     from cold and damp in the course of many generations,' have been
+     forced to raise themselves in the scale of civilization through the
+     practice of various arts, in the manner indicated by Mr.
+     Wallace[18]."
+
+    [18] _Descent of Man_, 1st Ed. ch. xx. (Trans. Dev. Assoc. for
+         Science, 1890).
+
+To this it may be added that the Chimpanzee "Sally" was largely denuded
+of hair, especially on the back, or the part of "man's organization" on
+which Mr. Wallace lays special stress, as being in this respect out of
+analogy with other mammalia[19].
+
+    [19] The late Prof. Moseley informed me that, during his voyage on
+         the _Challenger_, he had seen many men whose backs were well
+         covered with hair.--For an excellent discussion of the whole
+         question, chiefly in the light of embryology, see the paper by
+         Buckman already alluded to, pp. 280-289. Also, for an account
+         of an extraordinary hairy race of men, see _Alone with the
+         Hairy Ainu_, by A. H. Savage Landor, 1893.
+
+Lastly, touching his statement that the brain of savage man is both
+quantitatively and qualitatively in advance of his requirements, it is
+here also sufficient to refer to Darwin's answer, as given in the
+_Descent of Man_. Mr. Wallace, indeed, ignores this answer in his recent
+re-publication of the argument; but it is impossible to understand why
+he should have done so. To me, at all events, it seems that one out of
+several considerations which Darwin advances is alone sufficient to show
+the futility of this argument. I allude to the consideration that the
+power of forming abstract ideas with the complex machinery of language
+as the vehicle of their expression, is probably of itself enough to
+account for both the mass and the structure of a savage's brain. But
+this leads us to the second division of Mr. Wallace's argument, or that
+derived from the mental endowments of mankind.
+
+Here the peculiarities called into evidence are, "the Mathematical
+Faculty," "the Artistic Faculties," and "the Moral Sense." With regard
+to the latter, he avows himself a member of the intuitional school of
+ethics; but does not prove a very powerful advocate as against the
+utilitarian[20].
+
+    [20] E.g. "The special faculties we have been discussing clearly
+         point to the existence in man of something which he has not
+         derived from his animal progenitors--something which we may
+         best refer to as being of a spiritual essence or nature,
+         capable of progressive development under favourable conditions.
+         On the hypothesis of this spiritual nature, superadded to the
+         animal nature of man, we are able to understand much that is
+         otherwise mysterious or unintelligible in regard to him,
+         especially the enormous influence of ideas, principles, and
+         beliefs over his whole life and action. Thus alone can we
+         understand the constancy of the martyr, the unselfishness of
+         the philanthropist, the devotion of the patriot, the enthusiasm
+         of the artist, and the resolute and persevering search of the
+         scientific worker after nature's secrets. Thus we may perceive
+         that the love of truth, the delight in beauty, the passion for
+         justice, and the thrill of exultation with which we hear of any
+         act of courageous self-sacrifice, are the workings within us of
+         a higher nature which has not been developed by means of the
+         struggle for material existence." (_Darwinism_, p. 474.) I have
+         quoted this whole paragraph, because it is so inconsistent with
+         the rest of Mr. Wallace's system that a mere epitome of it
+         might well have been suspected of error. Given an intellectual
+         being, howsoever produced, and what is there "mysterious or
+         unintelligible" in "the enormous influence of ideas,
+         principles, and beliefs over his whole life and action"? Or
+         again, if he be also a social being, what is the relevancy of
+         adducing "the constancy of the martyr," "the unselfishness of
+         the philanthropist," "the devotion of the patriot," "the love
+         of truth," "the passion for justice," "the thrill of exultation
+         when we hear of any act of courageous self-sacrifice," in
+         evidence _against_ the law of _utility_, or in order to prove
+         that a "nature" thus endowed has "_not_ been developed by means
+         of the struggle for existence," when once this struggle has
+         been transferred from individuals to communities? The whole
+         passage reads like an ironical satire in favour of "Darwinism,"
+         rather than a serious argument against it.
+
+It comes, then, to this. According to Mr. Wallace's eventual
+conclusion, man is to be separated from the rest of organic nature, and
+the steady progress of evolution by natural causes is to be regarded as
+stopped at its final stage, because the human mind presents the
+faculties of mathematical calculation and aesthetic perception. Surely,
+on antecedent grounds alone, it must be apparent that there is here no
+kind of proportion between the conclusion and the _data_ from which it
+is drawn. That we are not confined to any such grounds, I will now try
+to show.
+
+Let it be remembered, however, that in the following brief criticism I
+am not concerned with the issue as to whether, or how far, the
+"faculties" in question have owed their origin or their development to
+_natural selection_. I am concerned only with the doctrine that in order
+to account for such and such particular "faculty" of the human mind,
+some order of causation must be supposed other than what we call
+natural. I am not a Neo-Darwinist, and so have no desire to make
+"natural selection" synonymous with "natural causation" throughout the
+whole domain of life and of mind. And I quite agree with Mr. Wallace
+that, at any rate, the "aesthetic faculty" cannot conceivably have been
+produced by natural selection--seeing that it is of no conceivable
+life-serving value in any of the stages of its growth. Moreover, it
+appears to me that the same thing has to be said of the play instincts,
+sense of the ludicrous, and sundry other "faculties" of mind among the
+lower animals. It being thus understood that I am not differing from Mr.
+Wallace where he imposes "limits" on the powers of natural selection,
+but only where he seems to take for granted that this is the same thing
+as imposing limits on the powers of natural causation, my criticism is
+as follows.
+
+In the first place, it is a psychological fallacy to regard the
+so-called "faculties" of mind as analogous to "organs" of the body. To
+classify the latter with reference to the functions which they severally
+perform is to follow a natural method of classification. But it is an
+artificial method which seeks to partition mental _faculty_ into this,
+that, and the other mental _faculties_. Like all other purely artificial
+classifications, this one has its practical uses; but, also like them,
+it is destitute of philosophical meaning. This statement is so well
+recognized by psychologists, that there is no occasion to justify it.
+But I must remark that any cogency which Mr. Wallace's argument may
+appear to present, arises from his not having recognized the fact which
+the statement conveys. For, had he considered the mind as a whole,
+instead of having contemplated it under the artificial categories of
+constituent "faculties," he would probably not have laid any such
+special stress upon some of the latter. In other words, he would have
+seen that the general development of the human mind as a whole has
+presumably involved the growth of those conventionally abstracted parts,
+which he regards as really separate endowments. Or, if he should find it
+easier to retain the terms of his metaphor, we may answer him by saying
+that the "faculties" of mind are "correlated," like "organs" of the
+body; and, therefore, that any general development of the various other
+"faculties" have presumably entailed a collateral development of the two
+in question.
+
+Again, in the second place, it would seem that Mr. Wallace has not
+sufficiently considered the co-operation of either well-known natural
+causes, which must have materially assisted the survival of the fittest
+where these two "faculties" are concerned. For, even if we disregard the
+inherited effects of use--which, however, if entertained as possible in
+any degree at all, must have here constituted an important
+factor,--there remain on the one hand, the unquestionable influences of
+individual education and, on the other hand, of the selection principle
+operating in the mind itself.
+
+Taking these two points separately, it is surely sufficiently well known
+that individual education--or special training, whether of mind or
+body--usually raises congenital powers of any kind to a more or less
+considerable level above those of the normal type. In other words,
+whatever doubt there may be touching the _inherited_ effects of use,
+there can be no question touching the immense _developmental_ effects
+thereof in the individual life-time. Now, the conditions of savage life
+are not such as lead to any deliberate cultivation of the "faculties"
+either of the mathematical or aesthetic order. Consequently, as might be
+expected, we find both of them in what Mr. Wallace regards as but a
+"latent" stage of development. But in just the same way do we find that
+the marvellous powers of an acrobat when specially trained from
+childhood--say to curve his spine backwards until his teeth can bite his
+heels--are "latent" in all men. Or, more correctly, they are _potential
+in every child_. So it is with the prodigious muscular development of a
+trained athlete, and with any number of other cases where either the
+body or the mind is concerned. Why then should Mr. Wallace select the
+particular instances of the mathematical and aesthetic powers in savages
+as in any special sense "prophetic" of future development in trained
+members of civilized races? Although it is true that these "latent
+capacities and powers are unused by savages," is it not equally true
+that savages fail to use their latent capacities and powers as tumblers
+and athletes? Moreover, is it not likewise true that _as_ used by
+savages, or as occurring normally in man, such capacities and powers are
+no less poorly developed than are those of the "faculties" on which Mr.
+Wallace lays so much stress? In other words, are not "latent capacities
+and powers" of all kinds more or less equally in excess of anything that
+is ever required of them by man in a state of nature? Therefore, if we
+say that where mathematics and the fine arts are concerned the potential
+capacities of savage man are in some mystical sense "prophetic" of a
+Newton or a Beethoven, so in consistency ought we to say that in these
+same capacities we discern a similar prophecy of those other uses of
+civilized life which we have in a rope-dancer or a clown.
+
+Again, and in addition to this, it should be remembered that, even if we
+do suppose any prophecy of this kind where the particular capacities in
+question are concerned, we must clearly extend the reference to the
+lower animals. Not a few birds display aesthetic feelings in a measure
+fairly comparable with those of savages; while we know that some animals
+present the germs of a "faculty" of computation[21]. But, it is
+needless to add, this fact is fatal to Mr. Wallace's argument as I
+understand it--viz. that the "faculties" in question have been in some
+special manner communicated by some superior intelligence to _man_.
+
+    [21] See _Proc. Zool. Soc._ June 4, 1889, for an account of the
+         performances in this respect of the Chimpanzee "Sally." Also,
+         for some remarks on the psychology of the subject, in _Mental
+         Evolution in Man_, p. 215. I should like to take this
+         opportunity of stating that, after the two publications above
+         referred to, this animal's instruction was continued, and that,
+         before her death, her "counting" extended as far as ten. That
+         is to say, any number of straws asked for from one to ten would
+         always be correctly given.
+
+Once more, it is obviously unfair to select such men as a "Newton, a La
+Place, a Gauss, or a Cayley" for the purpose of estimating the
+difference between savages and civilized man in regard to the latter
+"faculty." These men are the picked mathematicians of centuries.
+Therefore they are men who not only enjoyed all the highest possible
+benefits of individual culture, but likewise those who have been most
+endowed with mathematical power congenitally. So to speak, they are the
+best variations in this particular direction which our race is known to
+have produced. But had such variations arisen among savages it is
+sufficiently obvious that they could have come to nothing. Therefore, it
+is the _normal average_ of "mathematical faculty" in civilized man that
+should be contrasted with that of savage man; and, when due regard is
+paid to the all-important consideration which immediately follows, I
+cannot feel that the contrast presents any difficulty to the theory of
+human evolution by natural causation.
+
+Lastly, the consideration just alluded to is, that civilized man enjoys
+an advantage over savage man far in advance even of those which arise
+from a settled state of society, incentives to intellectual training,
+and so on. This inestimable advantage consists in the art of writing,
+_and the consequent transmission of the effects of culture from
+generation to generation_. Quite apart from any question as to the
+hereditary transmission of acquired characters, we have in this
+_intellectual_ transmission of acquired _experience_ a means of
+accumulative cultivation quite beyond our powers to estimate. For,
+unlike all other cases where we recognize the great influence of
+individual use or practice in augmenting congenital "faculties" (such as
+in the athlete, pianist, &c.), in this case the effects of special
+cultivation do not end with the individual life, but are carried on and
+on through successive generations _ad infinitum_. Hence, a civilized man
+inherits mentally, if not physically, the effects of culture for ages
+past, and this in whatever direction he may choose to profit therefrom.
+Moreover--and I deem this an immensely important addition--in this
+unique department of purely intellectual transmission, a kind of
+non-physical natural selection is perpetually engaged in producing the
+best results. For here a struggle for existence is constantly taking
+place among "ideas," "methods," and so forth, in what may be termed a
+psychological environment. The less fit are superseded by the more fit,
+and this not only in the mind of the individual, but, through language
+and literature, still more in the mind of the race. "A Newton, a La
+Place, a Gauss, or a Cayley," would all alike have been impossible, but
+for a previously prolonged course of mental evolution due to the
+selection principle operating in the region of mathematics, by means of
+continuous survivals of the best products in successive generations.
+And, of course, the same remark applies to art in all its branches[22].
+
+    [22] In Prof. Lloyd Morgan's _Animal Life and Intelligence_ there is
+         an admirable discussion on this subject, which has been
+         published since the above was written. The same has to be said
+         of Weismann's Essay on Music, where much that I have here said
+         is anticipated. With the views and arguments which Mr. Mivart
+         has forcibly set forth I have already dealt to the best of my
+         ability in a work on _Mental Evolution in Man_.
+
+Quitting then the last, and in my opinion the weakest chapter of
+_Darwinism_, the most important points presented by other portions of
+this work are--to quote its author's own enumeration of them--an
+attempted "proof that all specific characters are (or once have been)
+either useful in themselves or correlated with useful characters": an
+attempted "proof that natural selection can, in certain cases, increase
+the sterility of crosses": an attempted "proof that the effects of use
+and disuse, even if inherited, must be overpowered by natural
+selection": an attempted proof that the facts of variation in nature are
+in themselves sufficient to meet the difficulty which arises against the
+theory of natural selection, as held by him, from the swamping effects
+of free intercrossing: and, lastly, "a fuller discussion on the colour
+relations of animals, with additional facts and arguments on the origin
+of sexual differences of colour." As I intend to deal with all these
+points hereafter, excepting the last, it will be sufficient in this
+opening chapter to remark, that in as far as I disagree with Mr. Wallace
+(and agree with Darwin), on the subject of "sexual differences of
+colour," my reasons for doing so have been already sufficiently stated
+in Part I. But there is much else in his treatment of this subject which
+appears to me highly valuable, and therefore presenting an admirable
+contribution to the literature of Darwinism. In particular, it appears
+to me that the most important of his views in this connexion probably
+represents the truth--namely, that, among the higher animals, more or
+less conspicuous peculiarities of colour have often been acquired for
+the purpose of enabling members of the same species quickly and
+certainly to recognize one another. This theory was first published by
+Mr. J. E. Todd, in 1888, and therefore but a short time before its
+re-publication by Mr. Wallace. As his part in the matter has not been
+sufficiently recognized, I should like to conclude this introductory
+chapter by drawing prominent attention to the merits of Mr. Todd's
+paper. For not only has it the merit of priority, but it deals with the
+whole subject of "recognition colours"--or, as he calls them, "directive
+colours"--in a more comprehensive manner than has been done by any of
+his successors. In particular, he shows that the principle of
+recognition-marking is not restricted to facilitating sexual
+intercourse, but extends also to several other matters of importance in
+the economy of animal life[23].
+
+    [23] _American Naturalist_, xxii. pp. 201-207.
+
+       *       *       *       *       *
+
+Having thus briefly sketched the doctrines of the sundry Post-Darwinian
+Schools from a general point of view, I shall endeavour throughout the
+rest of this treatise to discuss in appropriate detail the questions
+which have more specially come to the front in the post-Darwinian
+period. It can scarcely be said that any one of these questions has
+arisen altogether _de novo_ during this period; for glimmerings, more or
+less conspicuous, of all are to be met with in the writings of Darwin
+himself. Nevertheless it is no less true that only after his death have
+they been lighted up to the full blaze of active discussion[24]. By far
+the most important of them are those to which the rest of this treatise
+will be confined. They are four in number, and it is noteworthy that
+they are all intimately connected with the great question which Darwin
+spent the best years of his life in contemplating, and which has
+therefore, in one form or another, occupied the whole of the present
+chapter--the question as to whether natural selection has been the sole
+cause, or but the chief cause of modification.
+
+    [24] It is almost needless to say that besides the works mentioned
+         in this chapter, many others have been added to the literature
+         of Darwinism since Darwin's death. But as none of these profess
+         to contain much that is original, I have not thought it
+         necessary to consider any of them in this merely general review
+         of the period in question. In subsequent chapters, however,
+         allusions will be made to those among them which I deem of most
+         importance.
+
+         [Since this note was written and printed the following works
+         have been published to which it does not apply: _Animal Life
+         and Intelligence_, by Professor Lloyd Morgan; _The Colours of
+         Animals_, by Professor Poulton; and _Materials for the Study of
+         Variation_, by Mr. Bateson. All these works are of high value
+         and importance. Special reference should also be made to
+         Professor Weismann's Essays.]
+
+The four questions above alluded to appertain respectively to Heredity,
+Utility, Isolation, and Physiological Selection. Of these the first two
+will form the subject-matter of the present volume, while the last two
+will be dealt with in the final instalment of _Darwin, and after
+Darwin_.
+
+
+
+
+SECTION I
+
+_HEREDITY_
+
+
+
+
+CHAPTER II.
+
+CHARACTERS AS HEREDITARY AND ACQUIRED (PRELIMINARY).
+
+
+We will proceed to consider, throughout Section I of the present work,
+the most important among those sundry questions which have come to the
+front since the death of Darwin. For it was in the year after this event
+that Weismann published the first of his numerous essays on the subject
+of Heredity, and, unquestionably, it has been these essays which have
+given such prominence to this subject during the last decade.
+
+At the outset it is desirable to be clear upon certain points touching
+the history of the subject; the limits within which our discussion is to
+be confined; the relation in which the present essay stands to the one
+that I published last year under the title _An Examination of
+Weismannism_; and several other matters of a preliminary kind.
+
+The problems presented by the phenomena of heredity are manifold; but
+chief among them is the hitherto unanswered question as to the
+transmission or non-transmission of acquired characters. This is the
+question to which the present Section will be confined.
+
+Although it is usually supposed that this question was first raised by
+Weismann, such was not the case. Any attentive reader of the successive
+editions of Darwin's works may perceive that at least from the year 1859
+he had the question clearly before his mind; and that during the rest of
+his life his opinion with regard to it underwent considerable
+modifications--becoming more and more Lamarckian the longer that he
+pondered it. But it was not till 1875 that the question was clearly
+presented to the general public by the independent thought of Mr.
+Galton, who was led to challenge the Lamarckian factors _in toto_ by way
+of deduction from his theory of Stirp--the close resemblance of which to
+Professor Weismann's theory of Germ-plasm has been shown in my
+_Examination of Weismannism_. Lastly, I was myself led to doubt the
+Lamarckian factors still further back in the seventies, by having found
+a reason for questioning the main evidence which Mr. Darwin had adduced
+in their favour. This doubt was greatly strengthened on reading, in the
+following year, Mr. Galton's _Theory of Heredity_ just alluded to; and
+thereupon I commenced a prolonged course of experiments upon the
+subject, the general nature of which will be stated in future chapters.
+Presumably many other persons must have entertained similar misgivings
+touching the inheritance of acquired characters long before the
+publication of Weismann's first essay upon the subject in 1883. The
+question as to the inheritance of acquired characters was therefore
+certainly not first raised by Weismann--although, of course, there is no
+doubt that it was conceived by him independently, and that he had the
+great merit of calling general attention to its existence and
+importance. On the other hand, it cannot be said that he has succeeded
+in doing very much towards its solution. It is for these reasons that
+any attempt at dealing with Weismann's fundamental postulate--i.e. that
+of the non-inheritance of acquired characters--was excluded from my
+_Examination of Weismannism_. As there stated, he is justified in
+assuming, for the purposes of his discussion, a negative answer to the
+question of such inheritance; but evidently the question itself ought
+not to be included within what we may properly understand by
+"Weismannism." Weismannism, properly so called, is an elaborate system
+of theories based on the fundamental postulate just mentioned--theories
+having reference to the mechanism of heredity on the one hand, and to
+the course of organic evolution on the other. Now it was the object of
+the foregoing _Examination_ to deal with this system of theories _per
+se_; and therefore we have here to take a new point of departure and to
+consider separately the question of fact as to the inheritance or
+non-inheritance of acquired characters. At first sight, no doubt, it
+will appear that in adopting this method I am putting the cart before
+the horse. For it may well appear that I ought first to have dealt with
+the validity of Weismann's postulate, and not till then to have
+considered the system of theories which he has raised upon it. But this
+criticism is not likely to be urged by any one who is well acquainted
+with the questions at issue. For, in the first place, it is notorious
+that the question of fact is still open to question; and therefore it
+ought to be considered separately, or apart from any theories which may
+have been formed with regard to it. In the second place, our judgement
+upon this question of fact must be largely influenced by the validity of
+general reasonings, such as those put forward in the interests of rival
+theories of heredity; and, as the theory of germ-plasm has been so
+thoughtfully elaborated by Professor Weismann, I have sought to give it
+the attention which it deserves as preliminary to our discussion of the
+question of fact which now lies before us. Thirdly and lastly, even if
+this question could be definitely answered by proving either that
+acquired characters are inherited or that they are not, it would by no
+means follow that Weismann's theory of heredity would be proved wholly
+false in the one case, or wholly true in the other. That it need not be
+wholly true, even were its fundamental postulate to be proved so, is
+evident, because, although the fact might be taken to prove the theory
+of Continuity, the theory of Germ-plasm is, as above stated, very much
+more than this. That the theory of Germ-plasm need not be wholly false,
+even if acquired characters should ever be proved heritable, a little
+thought may easily show, because, in this event, the further question
+would immediately arise as to the degrees and the comparative frequency
+of such inheritance. For my own part, as stated in the _Examination_, I
+have always been disposed to accept Mr. Galton's theory of Stirp in
+preference to that of Germ-plasm on this very ground--i. e. that it does
+not dogmatically exclude the possibility of an occasional inheritance of
+acquired characters in faint though cumulative degrees. And whatever our
+individual opinions may be touching the admissibility of such a _via
+media_ between the theories of Pangenesis and Germ-plasm, at least we
+may all agree on the desirability of fully considering the matter as a
+preliminary to the discussion of the question of fact.
+
+As it is not to be expected that even those who may have read my
+previous essay can now carry all these points in their memories, I will
+here re-state them in a somewhat fuller form.
+
+The following diagram will serve to give a clearer view of the sundry
+parts of Professor Weismann's system of theories, as well as of their
+relations to one another.
+
+[Illustration: Postulate as to the absolute non-inheritance of acquired
+characters.]
+
+Now, as just explained, the parts of this system which may be properly
+and distinctively called "Weismannism" are those which go to form the
+Y-like structure of deductions from the fundamental postulate.
+Therefore, it was the Y-like system of deductions which were dealt with
+in the _Examination of Weismannism_, while it is only his basal
+postulate which has to be dealt with in the following chapters.
+
+So much, then, for the relations of Weismann's system of theories to one
+another. It is, however, of even more importance that we should gain a
+clear view of the relations between his theory of _heredity_ to those of
+Darwin and of Galton, as preliminary to considering the fundamental
+question of fact.
+
+As we have already seen, the theory of germ-plasm is not only a theory
+of heredity: it is also, and more distinctively, a theory of evolution,
+&c. As a theory of heredity it is grounded on its author's fundamental
+postulate--the _continuity_ of germ-plasm. But as a theory of evolution,
+it requires for its support this additional postulate, that the
+continuity of germ-plasm has been _absolute_ "since the first origin of
+life." It is clear that this additional postulate is not needed for his
+theory of heredity, but only for his additional theory of evolution, &c.
+There have been one or two other theories of heredity, prior to this
+one, which, like it, have been founded on the postulate of Continuity of
+the substance of heredity; but it has not been needful for any of these
+theories to postulate further that this substance has been _always_ thus
+isolated, or even that it is now _invariably_ so. For even though the
+isolation be frequently invaded by influences of body-changes on the
+congenital characters of this substance, it does not follow that this
+principle of Continuity may not still be true _in the main_, even
+although it is supplemented in some degree by that of use-inheritance.
+Indeed, so far as the phenomena of heredity are concerned, it is
+conceivable that all congenital characters were originally acquired,
+and afterwards became congenital on account of their long inheritance. I
+do not myself advocate this view as biologically probable, but merely
+state it as logically possible, and in order to show that, so far as the
+phenomena of heredity are concerned, there appears to be no reason for
+Weismann's deduction that the principle of Continuity, if true at all,
+must be _absolute_. And it would further appear, the only reason why he
+makes this deduction (stem of the Y) is in order to provide a foundation
+for his further theories of evolution, &c. (arms of the Y). It is indeed
+necessary for these further theories that body-changes should never
+exercise any hereditary influence on the hereditary endowments of
+germ-plasm, and therefore it is that he posits the substance of heredity
+as, not only continuous, but uninterruptably so "since the first origin
+of life."
+
+Now, this may be made more clear by briefly comparing Weismann's theory
+with those of Darwin and of Galton. Weismann's theory of heredity, then,
+agrees with its predecessors which we are considering in all the
+following respects. The substance of heredity is particulate; is mainly
+lodged in highly specialized cells; is nevertheless also distributed
+throughout the general cellular tissues, where it is concerned in all
+processes of regeneration, repair, and a-sexual reproduction; presents
+an enormously complex structure, in that every constituent part of a
+potentially future organism is represented in a fertilized ovum by
+corresponding particles; is everywhere capable of virtually unlimited
+multiplication, without ever losing its hereditary endowments; is often
+capable of carrying these endowments in a dormant state through a long
+series of generations until at last they reappear in what we recognize
+as recursions. Thus far all three theories are in agreement. In fact,
+the only matter of any great importance wherein they disagree has
+reference to the doctrine of Continuity[25]. For while Darwin's theory
+supposes the substance of heredity to be mainly formed anew in each
+ontogeny, and therefore that the continuity of this substance is for the
+most part interrupted in every generation[26], Weismann's theory
+supposes this substance to be formed only during the phylogeny of each
+species, and therefore to have been absolutely uninterrupted since the
+first origin of life.
+
+    [25] Originally, Weismann's further assumption as to the perpetual
+         stability of germ-plasm, "since the first origin of sexual
+         reproduction," was another very important point of difference,
+         but this has now been withdrawn.
+
+    [26] I say "_mainly_ formed anew," and "_for the most part_
+         interrupted," because even Darwin's theory does not, as is
+         generally supposed, exclude the doctrine of Continuity _in
+         toto_.
+
+But now, Galton's theory of heredity stands much nearer to Weismann's in
+this matter of Continuity; for it is, as he says, a theory of "modified
+pangenesis," and the modification consists in allowing very much more
+for the principle of Continuity than is allowed by Darwin's theory; in
+fact he expresses himself as quite willing to adopt (on adequate grounds
+being shown) the doctrine of Continuity as absolute, and therefore
+propounded, as logically possible, the identical theory which was
+afterwards and independently announced by Weismann. Or, to quote his own
+words--
+
+     "We might almost reserve our belief that the structural [i. e.
+     somatic] cells can react on the sexual elements at all, and we may
+     be confident that at most they do so in a very faint degree; in
+     other words, that acquired modifications are barely, if at all,
+     _inherited_, in the correct sense of that word[27]."
+
+    [27] _Theory of Heredity_ (Journ. Anthrop. Inst. 1875, p. 346).
+
+So far Mr. Galton; but for Weismann's further theory of evolution, &c.,
+it is necessary to postulate the additional doctrine in question; and it
+makes a literally immeasurable difference to any theory of evolution
+whether or not we entertain this additional postulate. For no matter how
+faintly or how fitfully the substance of heredity may be modified by
+somatic tissues, the Lamarckian principles are hypothetically allowed
+some degree of play. And although this is a lower degree than Darwin
+supposed, their influence in determining the course of organic evolution
+may still have been enormous; seeing that their action in any degree
+must always have been _directive_ of variation on the one hand, and
+_cumulative_ on the other.
+
+Thus, by merely laying this theory side by side with Weismann's we can
+perceive at a glance how a _pure_ theory of _heredity_ admits of being
+based on the postulate of Continuity alone, without cumbering itself by
+any further postulate as to this Continuity being _absolute_. And this,
+in my opinion is the truly scientific attitude of mind for us to adopt
+as preliminary to the following investigation. For the whole
+investigation will be concerned--and concerned only--with this question
+of Continuity as absolute, or as admitting of degrees. There is, without
+any question, abundant evidence to prove that the substance of heredity
+is at least partly continuous (Gemmules). It may be that there is also
+abundant evidence to prove this substance much more _largely_
+continuous than Darwin supposed (Stirp); but be this as it may, it is
+certain that any such question as to the _degree_ of continuity differs,
+_toto caelo_, from that as to whether there can ever be any continuity
+at all.
+
+How, then, we may well ask, is it that so able a naturalist and so clear
+a thinker as Weismann can have so far departed from the inductive
+methods as to have not merely propounded the question touching
+Continuity and its degrees, or even of Continuity as absolute; but to
+have straightway assumed the latter possibility as a basis on which to
+run a system of branching and ever-changing speculations concerning
+evolution, variation, the ultimate structure of living material, the
+intimate mechanism of heredity, or, in short, such a system of deductive
+conjectures as has never been approached in the history of science? The
+answer to this question is surely not far to seek. Must it not be the
+answer already given? Must it not have been for the sake of rearing this
+enormous structure of speculation that Weismann has adopted the
+assumption of Continuity as absolute? As we have just seen, Galton had
+well shown how a theory of heredity could be founded on the general
+doctrine of Continuity, without anywhere departing from the inductive
+methods--even while fully recognizing the possibility of such continuity
+as absolute. But Galton's theory was a "_Theory of Heredity_," and
+nothing more. Therefore, while clearly perceiving that the Continuity in
+question _may_ be absolute, he saw no reason, either in fact or in
+theory, for concluding that it _must_ be. On the contrary, he saw that
+this question is, for the present, necessarily unripe for profitable
+discussion--and, _a fortiori_, for the shedding of clouds of seed in all
+the directions of "Weismannism."
+
+Hence, what I desire to be borne in mind throughout the following
+discussion is, that it will have exclusive reference to the question of
+fact already stated, without regard to any superjacent theories; and,
+still more, that there is a vast distinction between any question
+touching the degrees in which acquired characters are transmitted to
+progeny, and the question as to whether they are ever transmitted in any
+degree at all. Now, the latter question, being of much greater
+importance than the former, is the one which will mainly occupy our
+attention throughout the rest of this Section.
+
+We have already seen that before the subject was taken up by Weismann
+the difference between acquired and congenital characters in respect to
+transmissibility was generally taken to be one of degree; not one of
+kind. It was usually supposed that acquired characters, although not so
+fully and not so certainly inherited as congenital characters,
+nevertheless were inherited in some lesser degree; so that if the same
+acquired character continued to be successively acquired in a number of
+sequent generations, what was at first only a slight tendency to be
+inherited would become by summation a more and more pronounced tendency,
+till eventually the acquired character might become as strongly
+inherited as a congenital one. Or, more precisely, it was supposed that
+an acquired character, in virtue of such a summation of hereditary
+influence, would in time become congenital. Now, if this supposition be
+true, it is evident that more or less assistance must be lent to
+natural selection in its work of evolving adaptive modifications[28].
+And inasmuch as we know to what a wonderful extent adaptive
+modifications are secured during individual life-times--by the direct
+action of the environment on the one hand, and by increased or
+diminished use of special organs and mental faculties on the other--it
+becomes obvious of what importance even a small measure of
+transmissibility on their part would be in furnishing to natural
+selection ready-made variations in required directions, as distinguished
+from promiscuous variations in all directions. Contrariwise, if
+functionally-produced adaptations and adaptations produced by the direct
+action of the environment are never transmitted in any degree, not only
+would there be an incalculable waste, so to speak, of adaptive
+modifications--these being all laboriously and often most delicately
+built up during life-times of individuals only to be thrown down again
+as regards the interest of species--but so large an additional burden
+would be thrown upon the shoulders of natural selection that it becomes
+difficult to conceive how even this gigantic principle could sustain it,
+as I shall endeavour to show more fully in future chapters. On the other
+hand, however, Weismann and his followers not only feel no difficulty in
+throwing overboard all this ready-made machinery for turning out
+adaptive modifications when and as required; but they even represent
+that by so doing they are following the logical maxim, _Entia non sunt
+multiplicanda praeter necessitatem_--which means, in its relation to
+causality, that we must not needlessly multiply hypothetical principles
+to explain given results. But when appeal is here made to this logical
+principle--the so-called Law of Parsimony--two things are forgotten.
+
+    [28] Mr. Platt Ball has, indeed, argued that "use-inheritance would
+         often be an evil," since, for example, "the condyle of the
+         human jaw would become larger than the body of the jaw, because
+         as the fulcrum of the lever it receives more pressure"; and
+         similarly as regards many other hypothetical cases which he
+         mentions. (_The Effects of Use and Disuse_, pp. 128-9 _et
+         seq._) But it is evident that this argument proves too much.
+         For if the effects of use and disuse as transmitted to progeny
+         would be an evil, it could only be because these effects as
+         they occur in the parents are an evil--and this they most
+         certainly are not, being, on the contrary and as a general
+         rule, of a high order of adaptive value. Moreover, in the race,
+         there is a superadded agency always at work, which must
+         effectually prevent any undue accumulation of these
+         effects--namely, natural selection, which every Darwinist
+         accepts as a controlling principle of all or any other
+         principles of change. Therefore, if, as first produced in the
+         life-time of individuals, the effects of use and disuse are not
+         injurious, much less can they become so if transmitted through
+         the life-time of species. Again, Mr. Wallace argues that, even
+         supposing use-inheritance to occur, its adapting work in the
+         individual can never extend to the race, seeing that the
+         natural selection of fortuitous variations in the directions
+         required must always produce the adaptations _more quickly_
+         than would be possible by use-inheritance. This argument, being
+         one of more weight, will be dealt with in a future chapter.
+
+In the first place, it is forgotten that the very question in debate is
+whether causes of the Lamarckian order _are_ unnecessary to explain all
+the phenomena of organic nature. Of course if it could be proved that
+the theory of natural selection alone is competent to explain all these
+phenomena, appeal to the logical principle in question would be
+justifiable. But this is precisely the point which the followers of
+Darwin refuse to accept; and so long as it remains the very point at
+issue, it is a mere begging the question to represent that a class of
+causes which have hitherto been regarded as necessary are, in fact,
+unnecessary. Or, in other words, when Darwin himself so decidedly held
+that these causes are necessary as supplements to natural selection, the
+burden of proof is quite as much on the side of Weismann and his
+followers to show that Darwin's opinion was wrong, as it is on the side
+of Darwin's followers to show that it was right. Yet, notwithstanding
+the elaborate structure of theory which Weismann has raised, there is
+nowhere one single fact or one single consideration of much importance
+to the question in debate which was not perfectly well known to Darwin.
+Therefore I say that all this challenging of Darwinists to justify their
+"Lamarckian assumptions" really amounts to nothing more than a pitting
+of opinion against opinion, where there is at least as much call for
+justification on the one side as on the other.
+
+Again, when these challenges are thrown down by Weismann and his
+followers, it appears to be forgotten that the conditions of their own
+theory are such as to render acceptance of the gauge a matter of great
+difficulty. The case is very much like that of a doughty knight pitching
+his glove into the sea, and then defying any antagonist to take it up.
+That this is the case a very little explanation will suffice to show.
+
+The question to be settled is whether acquired characters are ever
+transmitted by heredity. Now suppose, for the sake of argument, that
+acquired characters are transmitted by heredity--though not so fully and
+not so certainly as congenital characters--how is this fact to be proved
+to the satisfaction of Weismann and his followers? First of all they
+answer,--Assuredly by adducing experimental proof of the inheritance of
+injuries, or mutilations. But in making this answer they appear to
+forget that Darwin has already shown its inefficiency. That the
+self-styled Neo-Lamarckians have been much more unguarded in this
+respect, I fully admit; but it is obviously unfair to identify Darwin's
+views with those of a small section of evolutionists, who are really as
+much opposed to Darwin's teaching on one side as is the school of
+Weismann on the other. Yet, on reading the essays of Weismann
+himself--and still more those of his followers--one would almost be led
+to gather that it is claimed by him to have enunciated the distinction
+between congenital and acquired characters in respect of
+transmissibility; and therefore also to have first raised the objection
+which lies against the theory of Pangenesis in respect of the
+non-transmissibility of mutilations. In point of fact, however, Darwin
+is as clear and decided on these points as Weismann. And his answer to
+the obvious difficulty touching the non-transmissibility of mutilations
+is, to quote his own words, "the long-continued inheritance of a part
+which has been removed during many generations is no real anomaly, for
+gemmules formerly derived from the part are multiplied and transmitted
+from generation to generation[29]." Therefore, so far as Darwin's theory
+is concerned, the challenge to produce evidence of the transmission of
+injuries is irrelevant: it is no more a part of Darwin's theory than it
+is of Weismann's to maintain that injuries _are_ transmitted.
+
+    [29] _Variation under Domestication_, ii. 392.
+
+There is, however, one point in this connexion to which allusion must
+here be made. Although Darwin did not believe in the transmissibility
+of mutilations when these consist merely in the amputation of parts of
+an organism, he did believe in a probable tendency to transmission when
+removal of the part is followed by gangrene. For, as he says, in that
+case, all the gemmules of the mutilated or amputated part, as they are
+gradually attracted to that part (in accordance with the law of affinity
+which the theory assumes), will be successively destroyed by the morbid
+process. Now it is of importance to note that Darwin made this exception
+to the general rule of the non-transmissibility of mutilations, not
+because his theory of pangenesis required it, but because there appeared
+to be certain very definite observations and experiments--which will be
+mentioned later on--proving that when mutilations are followed by
+gangrene they are apt to be inherited: his object, therefore, was to
+reconcile these alleged facts with his theory, quite as much as to
+sustain his theory by such facts.
+
+So much, then, for the challenge to produce direct evidence of the
+transmissibility of acquired characters, so far as mutilations are
+concerned: believers in Darwin's theory, as distinguished from
+Weismann's, are under no obligation to take up such a challenge. But the
+challenge does not end here. Show us, say the school of Weismann, a
+single instance where an acquired character _of any kind_ (be it a
+mutilation or otherwise) has been inherited: this is all that we
+require: this is all that we wait for: and surely, unless it be
+acknowledged that the Lamarckian doctrine reposes on mere assumption, at
+least one such case ought to be forthcoming. Well, nothing can sound
+more reasonable than this in the first instance; but as soon as we
+begin to cast about for cases which will satisfy the Neo-Darwinians, we
+find that the structure of their theory is such as to preclude, in
+almost every conceivable instance, the possibility of meeting their
+demand. For their theory begins by assuming that natural selection is
+the one and only cause of organic evolution. Consequently, what their
+demand amounts to is throwing upon the other side the burden of
+disproving this assumption--or, in other words, of proving the negative
+that in any given case of transmitted adaptation natural selection has
+_not_ been the sole agent at work. Now, it must obviously be in almost
+all cases impossible to prove this negative among species in a state of
+nature. For, even supposing that among such species Lamarckian
+principles have had a large share in the formation of hereditary and
+adaptive characters, how would Weismann himself propose that we should
+set about the proof of such a fact, where the proof demanded by his
+assumption is, that the _abstract possibility_ of natural selection
+having had anything to do with the matter must be excluded? Obviously
+this is impossible in the case of inherited characters which are also
+_adaptive_ characters. How then does it fare with the case of inherited
+characters which are not also adaptive? Merely that this case is met by
+another and sequent assumption, which constitutes an integral part of
+the Neo-Darwinian creed--namely, that in nature there _can be no such
+characters_. Seeing that natural selection is taken to be the only
+possible cause of change in species, it follows that all changes
+occurring in species must necessarily be adaptive, whether or not we are
+able to perceive the adaptations. In this way apparently useless
+characters, as well as obviously useful ones, are ruled out of the
+question: that is to say, _all_ hereditary characters of species in a
+state of nature are _assumed_ to be due to natural selection, and then
+it is demanded that the validity of this assumption should be disproved
+by anybody who doubts it. Yet Weismann himself would be unable to
+suggest any conceivable method by which it can be disproved among
+species in a state of nature--and this even supposing that the
+assumption is entirely false[30].
+
+    [30] In subsequent chapters, especially devoted to the question
+         (i.e. Section II), the validity of this assumption will be
+         considered on its own merits.
+
+Consequently, the only way in which these speciously-sounding challenges
+can be adequately met is by removing some individuals of a species from
+a state of nature, and so from all known influences of natural
+selection; then, while carefully avoiding artificial selection, causing
+these individuals and their progeny through many generations unduly to
+exercise some parts of their bodies, or unduly to fail in the exercise
+of others. But, clearly, such an experiment is one that must take years
+to perform, and therefore it is now too early in the day to reproach the
+followers of Darwin with not having met the challenges which are thrown
+down by the followers of Weismann[31].
+
+    [31] I say "the followers of Weismann," because Weismann himself,
+         with his clear perception of the requirements of experimental
+         research, expressly states the above considerations, with the
+         conclusions to which they lead. Nevertheless, he is not
+         consistent in his utterances upon this matter; for he
+         frequently expresses himself to the effect, "that the _onus
+         probandi_ rests with my opponents, and therefore they ought to
+         bring forward actual proofs" (_Essays_, i. p. 390). But, as
+         above shown, the _onus_ rests as much with him as with his
+         opponents; while, even if his opponents are right, he elsewhere
+         recognizes that they can bring "actual proofs" of the fact only
+         as a result of experiments which must take many years to
+         perform.
+
+Probably enough has now been said to show that the Neo-Darwinian
+assumption precludes the possibility of its own disproof from any of the
+facts of nature (as distinguished from domestication)--and this even
+supposing that the assumption be false. On the other hand, of course, it
+equally precludes the possibility of its own proof; and therefore it is
+as idle in Darwinists to challenge Weismann for proof of his negative
+(i. e. that acquired characters are not transmitted), as it is in
+Weismann to challenge Darwinists for proof of the opposite negative (i.
+e. that all seeming cases of such transmission are not due to natural
+selection). This dead-lock arises from the fact that in nature it is
+beyond the power of the followers of Darwin to exclude the abstract
+possibility of natural selection in any given case, while it is equally
+beyond the power of the followers of Weismann to exclude the abstract
+possibility of Lamarckian principles. Therefore at present the question
+must remain for the most part a matter of opinion, based upon general
+reasoning as distinguished from special facts or crucial experiments.
+The evidence available on either side is presumptive, not
+demonstrative[32]. But it is to be hoped that in the future, when time
+shall have been allowed for the performance of definite experiments on a
+number of generations of domesticated plants or animals, intentionally
+shielded from the influences of natural selection while exposed to those
+of the Lamarckian principles, results will be gained which will finally
+settle the question one way or the other.
+
+    [32] Note A.
+
+Meanwhile, however, we must be content with the evidence as it stands;
+and this will lead us to the second division of our subject. That is to
+say, having now dealt with the antecedent, or merely logical, state of
+the question, we have next to consider what actual, or biological,
+evidence there is at present available on either side of it. Thus far,
+neither side in the debate has any advantage over the other. On grounds
+of general reasoning alone they both have to rely on more or less
+dogmatic assumptions. For it is equally an unreasoned statement of
+opinion whether we allege that all the phenomena of organic evolution
+can be, or can not be, explained by the theory of natural selection
+alone. We are at present much too ignorant touching the causes of
+organic evolution to indulge in dogmatism of this kind; and if the
+question is to be referred for its answer to authority, it would appear
+that, both in respect of number and weight, opinions on the side of
+having provisionally to retain the Lamarckian factors are more
+authoritative than those _per contra_[33].
+
+    [33] For a fair and careful statement of the present balance of
+         authoritative opinion upon the question, see H. F. Osborn,
+         _American Naturalist_, 1892, pp. 537-67.
+
+       *       *       *       *       *
+
+Turning then to the question of fact, with which the following chapters
+are concerned, I will conclude this preliminary one with a few words on
+the method of discussion to be adopted.
+
+First I will give the evidence in favour of Lamarckianism; this will
+occupy the next two chapters. Then, in Chapter V, I will similarly give
+the evidence _per contra_, or in favour of Continuity as absolute.
+Lastly, I will sum up the evidence on both sides, and give my own
+judgement on the whole case. But on whichever side I am thus acting as
+special pleader for the time being, I will adduce only such arguments as
+seem to me valid--excluding alike from both the many irrelevant or
+otherwise invalid reasonings which have been but too abundantly
+published. Moreover, I think it will be convenient to consider all that
+has been said--or may be said--in the way of criticism to each argument
+by the opposite side while such argument is under discussion--i. e. not
+to wait till all the special pleading on one side shall have been
+exhausted before considering the exceptions which have been (or admit of
+being) taken to the arguments adduced, but to deal with such exceptions
+at the time when each of these arguments shall have been severally
+stated. Again, and lastly, I will arrange the evidence in each case--i.
+e. on both sides--under three headings, viz. (A) Indirect, (B) Direct,
+and (C) Experimental[34].
+
+    [34] [The above paragraph is allowed to remain exactly as Mr.
+         Romanes left it. Chapters V and VI were however not completed.
+         _See_ note appended to Preface. C. Ll. M.]
+
+
+
+
+CHAPTER III.
+
+CHARACTERS AS HEREDITARY AND ACQUIRED
+(_continued_).
+
+
+(A.)
+_Indirect Evidence in favour of the Inheritance of Acquired Characters._
+
+
+Starting with the evidence in favour of the so-called Lamarckian
+factors, we have to begin with the Indirect--and this without any
+special reference to the theories, either of Weismann or of others.
+
+It has already been shown, while setting forth in the preceding chapter
+the antecedent standing of the issue, that in this respect the _prima
+facie_ presumption is wholly on the side of the transmission, in greater
+degree or less, of acquired characters. Even Weismann allows that all
+"_appearances_" point in this direction, while there is no inductive
+evidence of the action of natural selection in any one case, either as
+regards germs or somas, and therefore, _a fortiori_, of the
+"all-sufficiency" of this cause[35]. It is true that in some of his
+earlier essays he has argued that there is no small weight of _prima
+facie_ evidence in favour of his own views as to the non-inheritance of
+acquired characters. This, however, will have to be considered in its
+proper place further on. Meanwhile I shall say merely in general terms
+that it arises almost entirely from a confusion of the doctrine of
+Continuity as absolute with that of Continuity as partial, and
+therefore, as admitting of degrees in different cases--which, as already
+explained, are doctrines wide as the poles asunder. But, leaving aside
+for the present such _prima facie_ evidence as Weismann has adduced on
+his side of the issue, I may quote him as a hostile witness to the
+weight of this kind of evidence _per contra_, in so far as it has
+already been presented in the foregoing chapter. Indeed, Weismann is
+much too logical a thinker not to perceive the cogency of the
+"appearances" which lie against his view of Continuity as
+absolute--although he has not been sufficiently careful in
+distinguishing between such Continuity and that which admits of degrees.
+
+    [35] See, especially, his excellent remarks on this point, _Contemp.
+         Rev._ Sept. 1893.
+
+We may take it, then, as agreed on all hands that whatever weight merely
+_prima facie_ evidence may in this matter be entitled to, is on the side
+of what I have termed moderated Lamarckianism: first sight "appearances"
+are against the Neo-Darwinian doctrine of the absolute non-inheritance
+of acquired characters.
+
+       *       *       *       *       *
+
+Let us now turn to another and much more important line of indirect
+evidence in favour of moderated Lamarckianism.
+
+The difficulty of _excluding the possibility_ of natural selection
+having been at work in the case of wild plants and animals has already
+been noticed. Therefore we may now appreciate the importance of all
+facts or arguments which _attenuate the probability_ of natural
+selection having been at work. This may be done by searching for cases
+in nature where a congenital structure, although unquestionably
+adaptive, nevertheless presents so small an amount of adaptation, that
+we can scarcely suppose it to have been arrived at by natural selection
+in the struggle for existence, as distinguished from the inheritance of
+functionally-produced modifications. For if functionally-produced
+modifications are ever transmitted at all, there is no limit to the
+minuteness of adaptive values which may thus become congenital; whereas,
+in order that any adaptive structure or instinct should be seized upon
+and accumulated by natural selection, it must from the very first have
+had an adaptive value sufficiently great to have constituted its
+presence a matter of life and death in the struggle for existence. Such
+structures or instincts must not only have always presented some measure
+of adaptive value, but this must always have been sufficiently great to
+reach what I have elsewhere called a selection-value. Hence, if we meet
+with cases in nature where adaptive structures or instincts present so
+low a degree of adaptive value that it is difficult to conceive how they
+could ever have exercised any appreciable influence in the battle for
+life, such cases may fairly be adduced in favour of the Lamarckian
+theory. For example, the Neo-Lamarckian school of the United States is
+chiefly composed of palaeontologists; and the reason of this seems to be
+that the study of fossil forms--or of species in process of
+formation--reveals so many instances of adaptations which in their
+nascent condition present such exceedingly minute degrees of adaptive
+value, that it seems unreasonable to attribute their development to a
+survival of the fittest in the complex struggle for existence. But as
+this argument is in my opinion of greatest force when it is applied to
+certain facts of physiology with which I am about to deal, I will not
+occupy space by considering any of the numberless cases to which the
+Neo-Lamarckians apply it within the region of palaeontology[36].
+
+    [36] There is now an extensive literature within this region. The
+         principal writers are Cope, Scott and Osborn. Unfortunately,
+         however, the facts adduced are not crucial as test-cases
+         between the rival theories--nearly all of them, in fact, being
+         equally susceptible of explanation by either.
+
+Turning then to inherited actions, it is here that we might antecedently
+expect to find our best evidence of the Lamarckian principles, if these
+principles have really had any share in the process of adaptive
+evolution. For we know that in the life-time of individuals it is
+action, and the cessation of action, which produce nearly all the
+phenomena of acquired adaptation--use and disuse in animals being merely
+other names for action and the cessation of action. Again, we know that
+it is where neuro-muscular machinery is concerned that we meet with the
+most conclusive evidence of the remarkable extent to which action is
+capable of co-ordinating structures for the ready performance of
+particular functions; so that even during the years of childhood
+"practice makes perfect" to the extent of organizing neuro-muscular
+adjustments, so elaborate and complete as to be indistinguishable from
+those which in natural species we recognized as reflex actions on the
+one hand, and instinctive actions on the other. Hence, if there be any
+such thing as "use-inheritance" at all, it is in the domain of reflex
+actions and instinctive actions that we may expect to find our best
+evidence of the fact. Therefore I will restrict the present line of
+evidence--(A)--to these two classes of phenomena, as together yielding
+the best evidence obtainable within this line of argument.
+
+       *       *       *       *       *
+
+The evidence in favour of the Lamarckian factors which may be derived
+from the phenomena of reflex action has never, I believe, been pointed
+out before; but it appears to me of a more cogent nature than perhaps
+any other. In order to do it justice, I will begin by re-stating an
+argument in favour of these factors which has already been adduced by
+previous writers, and discussed by myself in published correspondence
+with several leaders of the ultra-Darwinian school.
+
+Long ago Professor Broca and Mr. Herbert Spencer pointed to the facts of
+co-adaptation, or co-ordination within the limits of the same organism,
+as presenting good evidence of Lamarckian principles, working in
+association with natural selection. Thus, taking one of Lamarck's own
+illustrations, Mr. Spencer argued that there must be numberless
+changes--extending to all the organs, and even to all the tissues, of
+the animal--which in the course of many generations have conspired to
+convert an antelope into a giraffe. Now the point is, that throughout
+the entire history of these changes their utility must always have been
+dependent on their association. It would be useless that an incipient
+giraffe should present the peculiar form of the hind-quarters which we
+now perceive, unless at the same time it presented the correspondingly
+peculiar form of the fore-quarters; and as each of these great
+modifications entails innumerable subordinate modifications throughout
+both halves of the creature concerned, the chances must have been
+infinitely great against the required association of so many changes
+happening to have arisen congenitally in the same individuals by way of
+merely fortuitous variation. Yet, if we exclude the Lamarckian
+interpretation, which gives an intelligible _cause_ of co-ordination, we
+are required to suppose that such a happy concurrence of innumerable
+independent variations must have occurred by mere accident--and this on
+innumerable different occasions in the bodies of as many successive
+ancestors of the existing species. For at each successive stage of the
+improvement natural selection (if working alone) must have needed all,
+or at any rate most, of the co-ordinated parts to occur in the same
+individual organisms[37].
+
+    [37] For another and better illustration more recently published by
+         Mr. Spencer, see _The Inadequacy of Natural Selection_, p. 22.
+
+In alluding to what I have already published upon the difficulty which
+thus appears to be presented to his theory, Weismann says, "At no
+distant time I hope to be able to consider this objection, and to show
+that the apparent support given to the old idea [i. e. of the
+transmission of functionally-produced modifications] is really insecure,
+and breaks down as soon as it is critically examined[38]."
+
+    [38] _Essays on Heredity_, vol. i. p. 389.
+
+         [For further treatment of the subject under discussion _see_
+         Weismann, _The All-sufficiency of Natural Selection_ (Contemp.
+         Rev. Sept. and Oct. 1893), and _The Effect of External
+         Influences upon Development_. "Romanes Lecture" 1894, and
+         Spencer, _Weismannism once more_ (Cont. Rev. Oct. 1894). C. Ll.
+         M.]
+
+So much for what Weismann has said touching this matter. But the matter
+has also been dealt with both by Darwin and by Wallace. Darwin very
+properly distinguishes between the fallacy that "with animals such as
+the giraffe, of which the whole structure is admirably co-ordinated for
+certain purposes, it has been supposed that all the parts must have been
+simultaneously modified[39]," and the sound argument that the
+co-ordination itself cannot have been due to natural selection alone.
+This important distinction may be rendered more clear as follows.
+
+    [39] _Variation_, &c., vol. ii. p. 206.
+
+The facts of artificial selection prove that immense modifications of
+structure may be caused by a cumulative blending in the same individuals
+of characters which were originally distributed among different
+individuals. Now, in the parallel case of natural selection the
+characters thus blended will usually--if not invariably--be of an
+adaptive kind; and their eventual blending together in the same
+individuals will be due to free intercrossing of the most fit. But this
+_blending of adaptations_ is quite a different matter from the
+_occurrence of co-ordination_. For it belongs to the essence of
+co-ordination that each of the co-ordinated parts should be destitute of
+adaptive value _per se_: the adaptation only begins to arise if all the
+parts in question occur associated together in the same individuals
+_from the very first_. In this case it is obvious that the analogy of
+artificial selection can be of no avail in explaining the facts, since
+the difficulty presented has nothing to do with the blending in single
+individuals of adaptations previously distributed among different
+individuals; it has to do with the simultaneous appearance in single
+individuals of a co-adaptation of parts, none of which could ever have
+been of any adaptive value had it been previously distributed among
+different individuals. Consequently, where Darwin comes to consider this
+particular case (or the case of co-adaptation as distinguished from the
+blending of adaptations), he freely invokes the aid of the Lamarckian
+principles[40].
+
+    [40] E. g. _Origin of Species_, p. 178.
+
+Wallace, on the other hand, refuses to do this, and says that "the best
+answer to the difficulty" of supposing natural selection to have been
+the only cause of co-adaptation may be "found in the fact that the very
+thing said to be impossible by variation and natural selection, has been
+again and again affected by variation and artificial selection[41]."
+This analogy (which Darwin had already and very properly adduced with
+regard to the _blending of adaptations_) he enforces by special
+illustrations; but he does not appear to perceive that it misses the
+whole and only point of the "difficulty" against which it is brought.
+For the case which his analogy sustains is not that which Darwin,
+Spencer, Broca and others, mean by _co-adaptation_: it is the case of a
+blending of _adaptations_. It is not the case where adaptation is _first
+initiated in spite of intercrossing_, by a fortuitous concurrence of
+variations each in itself being without adaptive value: it is the case
+where adaptation is _afterwards increased by means of intercrossing_,
+through the blending of variations each of which has always been in
+itself of adaptive value.
+
+    [41] _Darwinism_, p. 418.
+
+From this I hope it will be apparent that the only way in which the
+"difficulty" from co-adaptation can be logically met by the
+ultra-Darwinian school, is by denying that the phenomenon of
+co-adaptation (as distinguished from the blending of adaptations) is
+ever to be really met with in organic nature. It may be argued that in
+all cases where co-adaptation _appears_ to occur, closer examination
+will show that the facts are really due to a blending of adaptations.
+The characters A + B + C + D, which are now found united in the same
+organism, and, as thus united, all conspiring to a common end, may
+originally have been distributed among different organisms, where they
+_severally_ subserved some other ends--or possibly the same end, though
+in a less efficient manner. Obviously, however, in this case their
+subsequent combination in the same organism would not be an instance of
+co-adaptation, but merely of an advantageous blending together of
+already existing adaptations. This argument, or rejoinder, has in point
+of fact been adopted by Professor Meldola, he believes that all cases of
+seeming co-adaptation are thus due to a mere blending of
+adaptations[42]. Of course, if this position can be maintained, the
+whole difficulty from co-adaptation would lapse. But even then it would
+lapse on the ground of _fact_. It would not have been overturned, or in
+any way affected, by Wallace's _argument_ from artificial selection.
+For, in that event, no such argument would be required, and, if adduced,
+would be irrelevant, since no one has ever alleged that there is any
+difficulty in understanding the mere confluence of adaptations by
+free-intercrossing of the best adapted.
+
+    [42] _Nature_, vol. xliii. pp. 410, 557; vol. xliv. pp. 7, 29. I say
+         "adopted," because I had objected to his quoting the analogy of
+         artificial selection, and stated, as above, that the only way
+         to meet Mr. Spencer's "difficulty" was to deny the fact of
+         co-adaptation as ever occurring in any case. It then appeared
+         that Professor Meldola agreed with me as to this. But I do not
+         yet understand why, if such were his view, he began by
+         endorsing Mr. Wallace's analogy from artificial selection--i.
+         e. confusing the case of co-adaptation with that of the
+         blending of adaptations. If any one denies the fact of
+         co-adaptation, he cannot assist his denial by arguing the
+         totally different fact that adaptations may be blended by free
+         intercrossing; for this latter fact has never been questioned,
+         and has nothing to do with the one which he engaged in
+         disputing.
+
+Now, if we are agreed that the only question in debate is the question
+of fact whether or not co-adaptation ever occurs in nature, it appears
+to me that the best field for debating the question is furnished by the
+phenomena of reflex action. I can well perceive that the instances
+adduced by Broca and Spencer in support of their common argument--such
+as the giraffe, the elk, &c.--are equivocal. But I think that many
+instances which may be adduced of reflex action are much more to the
+point. _For it belongs to the very nature of reflex action that it
+cannot work unless all parts of the machinery concerned are already
+present, and already co-ordinated, in the same organism._ It would be
+useless, in so far as such action is concerned if the afferent and
+efferent nerves, the nerve-centre, and the muscles organically grouped
+together, were not all present from the very first in the same
+individuals, and from the very first were not co-ordinated as a definite
+piece of organic machinery.
+
+With respect to reflex actions, therefore, it is desirable to begin by
+pointing out how widely the adaptations which they involve differ from
+those where no manufacture, so to speak, of special machinery is
+required. Thus, it is easy to understand how natural selection alone is
+capable of gradually accumulating congenital variations in the direction
+of protective colouring; of mimicry; of general size, form, mutual
+correlation of parts as connected with superior strength, fleetness,
+agility, &c.; of greater or less development of particular parts, such
+as legs, wings, tails, &c. For in all such cases the adaptation which is
+in process of accumulation is from its very commencement and throughout
+each of its subsequent stages, of _use_ in the struggle for existence.
+And inasmuch as all the individuals of each successive generation vary
+round the specific mean which characterized the preceding generation,
+there will always be a sufficient number of individuals which present
+congenital variations of the kind required for natural selection to
+seize upon, without danger of their being swamped by free
+intercrossing--as Mr. Wallace has very ably shown in his _Darwinism_.
+But this law of averages can apply only to cases where single
+structures--or a single group of correlated structures--are already
+present, and already varying round a specific mean. The case is quite
+different where a _co-ordination_ of structures is required for the
+performance of a _previously non-existent_ reflex action. For some, at
+least, of these structures must be _new_, as must also be the function
+which all of them first conspire to perform. Therefore, neither the new
+elements of structure, nor the new combination of structures, can have
+been previously given as varying round a specific mean. On the contrary,
+a very definite piece of machinery, consisting of many co-ordinated
+parts, must somehow or other be originated in a high degree of working
+efficiency, before it can be capable of answering its purpose in the
+prompt performance of a particular action under particular circumstances
+of stimulation. Lastly, such pieces of machinery are always of a highly
+delicate character, and usually involve so immensely complex a
+co-ordination of mutually dependent parts, that it is only a
+physiologist who can fully appreciate the magnitude of the distinction
+between "adaptations" of this kind, and "adaptations" of the kind which
+arise through natural selection seizing upon congenital variations as
+these oscillate round a specific mean.
+
+Or the whole argument may be presented in another form, under three
+different headings, thus:--
+
+In the first place, it will be evident from what has just been said,
+that such a piece of machinery as is concerned in even the simplest
+reflex action cannot have occurred in any considerable number of
+individuals of a species, _when it first began to be constructed_. On
+the contrary, if its _origin_ were dependent on congenital variations
+alone, the needful co-adaptation of parts which it requires can scarcely
+have happened to occur in more than a very small percentage of
+cases--even if it be held conceivable that by such means alone it should
+ever have occurred at all. Hence, instead of preservation and subsequent
+improvement having taken place _in consequence of_ free intercrossing
+among all individuals of the species (as in the cases of protective
+colouring, &c., where adaptation has no reference to any mechanical
+co-adaptation of parts), they must have taken place _in spite of_ such
+intercrossing.
+
+In the second place, adaptations due to organic machineries of this kind
+differ in another all-important respect from those due to a summation of
+adaptive characters which are already present and already varying round
+a specific mean. The latter depend for their summation upon the
+fact--not merely, as just stated, that they are already present, already
+varying round a specific mean, and therefore owe their progressive
+evolution to free intercrossing, but also--_that they admit of very
+different degrees of adaptation_. It is only because the degree of
+adaptation in generation B is superior to that in generation A that
+_gradual improvement_ in respect of adaptation is here possible. In the
+case of protective resemblance, for example, a very imperfect and merely
+accidental resemblance to a leaf, to another insect, &c., may at the
+first start have conferred a sufficient degree of adaptive imitation to
+count for something in the struggle for life; and, if so, the basis
+would be given for a progressive building up by natural selection of
+structures and colours in ever-advancing degrees of adaptive
+resemblance. There is here no necessity to suppose--nor in point of fact
+is it ever supposed, since the supposition would involve nothing short
+of a miracle--that such extreme perfection in this respect as we now so
+frequently admire has originated suddenly in a single generation, as a
+collective variation of a congenital kind affecting simultaneously a
+large proportional number of individuals. But in the case of a reflex
+mechanism--which may involve even greater marvels of adaptive
+adjustment, and _all_ the parts of which must occur in the same
+_individuals_ to be of any use--it _is_ necessary to suppose some such
+sudden and collective origin in some very high degree of efficiency, if
+natural selection has been the only principle concerned in afterwards
+perfecting the mechanism. For it is self-evident that a reflex action,
+from its very nature, cannot admit of any great differences in its
+degrees of adaptation: if it is to work at all, so as to count for
+anything in the struggle for life, it must already be given in a state
+of working efficiency. So that, unless we invoke either the doctrine of
+"prophetic types" or the theory of sudden creations, I confess I do not
+see how we are to explain either the origin, or the development, of a
+reflex mechanism by means of natural selection alone.
+
+Lastly, in the third place, _even when reflex mechanisms have been fully
+formed_, it is often beyond the power of sober credence to believe that
+they now are, or ever can have been, of selective value in the struggle
+for existence, as I will show further on. And such cases go to fortify
+the preceding argument. For if not conceivably of selective value even
+when completely evolved, much less can they conceivably have been so
+through all the stages of their complex evolution back to their very
+origin. Therefore, supposing for the present that there are such cases
+of reflex action in nature, neither their origin nor their development
+can conceivably have been due to natural selection alone. The Lamarckian
+factors, however, have no reference to degrees of adaptation, any more
+than they have to degrees of complexity. No question of value, as
+selective or otherwise, can obtain in their case: neither in their case
+does any difficulty obtain as regards the co-adaptation of severally
+useless parts.
+
+Now, if all these distinctions between the Darwinian and Lamarckian
+principles are valid--and I cannot see any possibility of doubt upon
+this point--strong evidence in favour of the latter would be furnished
+by cases (if any occur) where structures, actions, instincts, &c.,
+although of some adaptive value, are nevertheless plainly not of
+selective value. According to the ultra-Darwinian theory, no such cases
+ought ever to occur: according to the theory of Darwin himself, they
+ought frequently to occur. Therefore a good test, or criterion, as
+between these different theories of organic evolution is furnished by
+putting the simple question of fact--Can we, or can we not, show that
+there are cases of adaptation where the degree of adaptation is so small
+as to be incompatible with the supposition of its presenting a selective
+value? And if we put the wider question--Are there any cases where the
+co-adaptation of severally useless parts has been brought about, when
+even the resulting whole does not present a selective value?--then, of
+course, we impose a still more rigid test.
+
+Well, notwithstanding the difficulty of proving such a negative as the
+absence of natural selection where adaptive development is concerned, I
+believe that there are cases which conform to both these tests
+simultaneously; and, moreover, that they are to be found in most
+abundance where the theory of use-inheritance would most expect them to
+occur--namely, in the province of reflex action. For the very essence of
+this theory is the doctrine, that constantly associated use of the same
+parts for the performance of the same action will progressively organize
+those parts into a reflex mechanism--no matter how high a degree of
+co-adaptation may thus be reached on the one hand, or how low a degree
+of utilitarian value on the other.
+
+Having now stated the general or abstract principles which I regard as
+constituting a defence of the Lamarckian factors, so far as this admits
+of being raised on grounds of physiology, we will now consider a few
+concrete cases by way of illustration. It is needless to multiply such
+cases for the mere purpose of illustration. For, on reading those here
+given, every physiologist will at once perceive that they might be added
+to indefinitely. The point to observe is, the relation in which these
+samples of reflex action stand to the general principles in question;
+for there is nothing unusual in the samples themselves. On the contrary,
+they are chosen because they are fairly typical of the phenomena of
+reflex action in general.
+
+In our own organization there is a reflex mechanism which ensures the
+prompt withdrawal of the legs from any source of irritation supplied to
+the feet. For instance, even after a man has broken his spine in such a
+manner as totally to interrupt the functional continuity of his spinal
+cord and brain, the reflex mechanism in question will continue to
+retract his legs when his feet are stimulated by a touch, a burn, &c.
+This responsive action is clearly an adaptive action, and, as the man
+neither feels the stimulation nor the resulting movement, it is as
+clearly a reflex action. The question now is as to the mode of its
+origin and development.
+
+I will not here dwell upon the argument from co-adaptation, because this
+may be done more effectually in the case of more complicated reflex
+actions, but will ask whether we can reasonably hold that this
+particular reflex action--comparatively simple though it is--has ever
+been of selective value to the human species, or to the ancestors
+thereof? Even in its present fully-formed condition it is fairly
+questionable whether it is of any adaptive _value_ at all. The movement
+performed is no doubt an adaptive _movement_; but is there any occasion
+upon which the reflex mechanism concerned therein can ever have been of
+adaptive _use_? Until a man's legs have been paralyzed as to their
+voluntary motion, he will always promptly withdraw his feet from any
+injurious source of irritation by means of his conscious intelligence.
+True, the reflex mechanism secures an almost inappreciable saving in the
+time of response to a stimulus, as compared with the time required for
+response by an act of will; but the difference is so exceedingly small,
+that we can hardly suppose the saving of it in this particular case to
+be a matter of any adaptive--much less selective--importance. Nor is it
+more easy to suppose that the reflex mechanism has been developed by
+natural selection for the purpose of replacing voluntary action when the
+latter has been destroyed or suspended by grave spinal injury,
+paralysis, coma, or even ordinary sleep. In short, even if for the sake
+of argument we allow it to be conceivable that any single human being,
+ape, or still more distant ancestor, has ever owed its life to the
+possession of this mechanism, we may still be certain that not one in a
+million can have done so. And, if this is the case with regard to the
+mechanism as now fully constructed, still more must it have been the
+case with regard to all the previous stages of construction. For here,
+without elaborating the point, it would appear that a process of
+construction by survival of the fittest alone is incomprehensible.
+
+On the other hand, of course, the theory of use-inheritance furnishes a
+fully intelligible--whether or not a true--explanation. For those
+nerve-centres in the spinal cord which co-ordinate the muscles required
+for retracting the feet are the centres used by the will for this
+purpose. And, by hypothesis, the frequent use of them for this purpose
+under circumstances of stimulation which render the muscular response
+appropriate, will eventually establish an organic connexion between such
+response and the kind of stimulation to which it is appropriate--even
+though there be no utilitarian reason for its establishment[43]. To
+invert a phrase of Aristotle, we do not frequently use this mechanism
+because we have it (seeing that in our normal condition there is no
+necessity for such use); but, by hypothesis, we have it because we have
+frequently used its several elements in appropriate combination.
+
+    [43] It may be said, with regard to this particular reflex, that it
+         may perhaps be, so to speak, a mechanical accident, arising
+         from the contiguity of the sensory and motor roots in the cord.
+         But as this suggestion cannot apply to other reflexes presently
+         to be adduced, it need not be considered.
+
+I will adduce but one further example in illustration of these general
+principles--passing at once from the foregoing case of comparative
+simplicity to one of extreme complexity.
+
+There is a well-known experiment on a brainless frog, which reveals a
+beautiful reflex mechanism in the animal, whereby the whole body is
+enabled continually to readjust its balance on a book (or any other
+plane surface), as this is slowly rotated on a horizontal axis. So long
+as the book is lying flat, the frog remains motionless; but as soon as
+the book is tilted a little, so that the frog is in danger of slipping
+off, all the four feet begin to crawl up the hill; and the steeper the
+hill becomes, the faster they crawl. When the book is vertical, the frog
+has reached the now horizontal back, and so on. Such being the facts,
+the question is--How can the complicated piece of machinery thus implied
+have been developed by natural selection? Obviously it cannot have been
+so by any of the parts concerned having been originally distributed
+among different individuals, and afterwards united in single individuals
+by survival (i.e. free intercrossing) of the fittest. In other words,
+the case is obviously one of co-adaptation, and not one of the blending
+of adaptations. Again, and no less obviously, it is impossible that the
+co-adaptation can have been _gradually developed_ by natural selection,
+because, in order to have been so, it must by hypothesis have been of
+some degree of use in every one of its stages; yet it plainly cannot
+have been until it had been fully perfected in all its astonishing
+complexity[44].
+
+    [44] Of course it will be observed that the question is not with
+         regard to the development of all the nerves and muscles
+         concerned in this particular process. It is as to the
+         development of the co-ordinating centres, which thus so
+         delicately respond to the special stimuli furnished by
+         variations of angle to the horizon. And it is as inconceivable
+         in this case of reflex action, as it is in almost every other
+         case of reflex action, that the highly specialized machinery
+         required for performing the adaptive function can ever have had
+         its origin in the performance of any other function. Indeed, a
+         noticeable peculiarity of reflex mechanisms as a class is the
+         highly specialized character of the functions which their
+         highly organized structures subserve.
+
+Lastly, not only does it thus appear impossible that during all stages
+of its development--or while as yet incapable of performing its
+intricate function--this nascent mechanism can have had any adaptive
+value; but even as now fully developed, who will venture to maintain
+that it presents any selective value? As long as the animal preserves
+its brain, it will likewise preserve its balance, by the exercise of its
+intelligent volition. And, if the brain were in some way destroyed, the
+animal would be unable to breed, or even to feed; so that natural
+selection can never have had any _opportunity_, so to speak, of
+developing this reflex mechanism in brainless frogs. On the other hand,
+as we have just seen, we cannot perceive how there can ever have been
+any _raison d'etre_ for its development in normal frogs--even if its
+development were conceivably possible by means of this agency. But if
+practice makes perfect in the race, as it does in the individual, we can
+immediately perceive that the constant habit of correctly adjusting its
+balance may have gradually developed, in the batrachian organization,
+this non-necessary reflex[45].
+
+    [45] We meet with a closely analogous reflex mechanism in brainless
+         vertebrata of other kinds; but these do not furnish such good
+         test cases, because the possibility of natural selection cannot
+         be so efficiently attenuated. The perching of brainless birds,
+         for instance, at once refers us to the roosting of sleeping
+         birds, where the reflex mechanism concerned is clearly of high
+         adaptive value. Therefore such a case is not available as a
+         test, although the probability is that birds have inherited
+         their balancing mechanisms from their sauropsidian ancestors,
+         where it would have been of no such adaptive importance.
+
+And, of course, this example--like that of withdrawing the feet from a
+source of stimulation, which a frog will do as well as a man--does not
+stand alone. Without going further a-field than this same animal, any
+one who reads, from our present point of view, Goltz's work on the
+reflex actions of the frog, will find that the great majority of
+them--complex and refined though most of them are--cannot conceivably
+have ever been of any use to any frog that was in undisturbed possession
+of its brain.
+
+Hence, not to occupy space with a reiteration of facts all more or less
+of the same general kind, and therefore all presenting identical
+difficulties to ultra-Darwinian theory, I shall proceed to give two
+others which appear to me of particular interest in the present
+connexion, because they furnish illustrations of reflex actions in a
+state of only partial development, and are therefore at the present
+moment demonstrably useless to the animal which displays them.
+
+Many of our domesticated dogs, when we gently scratch their sides and
+certain other parts of the body, will themselves perform scratching
+movements with the hind leg of the same side as that upon which the
+irritation is being supplied. According to Goltz[46], this action is a
+true reflex; for he found that it is performed equally well in a dog
+which has been deprived of its cerebral hemispheres, and therefore of
+its normal volition. Again, according to Haycraft[47], this reflex is
+congenital, or not acquired during the life-time of each individual dog.
+Now, although the action of scratching is doubtless adaptive, it appears
+to me incredible that it could ever have become organized into a
+congenital reflex by natural selection. For, in order that it should,
+the scratching away fleas would require to have been a function of
+selective value. Yet, even if the irritation caused by fleas were
+supposed to be so far fatal in the struggle for existence, it is certain
+that they would always be scratched away by the conscious intelligence
+of each individual dog; and, therefore, that no advantage could be
+gained by organizing the action into a reflex. On the other hand, if
+acquired characters are ever in any degree transmitted, it is easy to
+understand how so frequently repeated an action should have become, in
+numberless generations of dogs, congenitally automatic.
+
+    [46] _Pflueger's Archiv_, Bd. xx. s. 23 (1879).
+
+    [47] _Brain_, part xlviii, pp. 516-19 (1889).--There is still better
+         proof of this in the case of certain rodents. For instance,
+         observing that rats and mice are under the necessity of very
+         frequently scratching themselves with their hind-feet, I tried
+         the experiment of removing the latter from newly-born
+         individuals--i.e. before the animals were able to co-ordinate
+         their movements, and therefore before they had ever even
+         attempted to scratch themselves. Notwithstanding that they were
+         thus destitute of individual experience with regard to the
+         benefit of scratching, they began their scratching movements
+         with their stumps as soon as they were capable of executing
+         co-ordinated movements, and afterwards continued to do so till
+         the end of their lives with as much vigour and frequency as
+         unmutilated animals. Although the stumps could not reach the
+         seats of irritation which were bent towards them, they used to
+         move rapidly in the air for a time sufficient to have given the
+         itching part a good scratch, had the feet been present--after
+         which the animals would resume their sundry other avocations
+         with apparent satisfaction. These facts showed the hereditary
+         response to irritation by parasites to be so strong, that even
+         a whole life-time's experience of its futility made no
+         difference in the frequency or the vigour thereof.
+
+So much for the general principle of selective value as applied to this
+particular case. And similarly, of course, we might here repeat the
+application of all the other general principles, which have just been
+applied in the two preceding cases. But it is only one of these other
+general principles which I desire in the present case specially to
+consider, for the purpose of considering more closely than hitherto the
+difficulty which this principle presents to ultra-Darwinian theory.
+
+The difficulty to which I allude is that of understanding how all the
+stages in the _development_ of a reflex action can have been due to
+natural selection, seeing that, before the reflex mechanism has been
+sufficiently elaborated to perform its function, it cannot have
+presented any degree of utility. Now the particular force of the present
+example, the action of scratching--as also of the one to
+follow--consists in the fact that it is a case where a reflex action is
+not yet completely organized. It appears to be only in course of
+construction, so that it is neither invariably present, nor, when it is
+present, is it ever fully adapted to the performance of its function.
+
+That it is not invariably present (when the brain is so) may be proved
+by trying the simple experiment on a number of puppies--and also of
+full-grown dogs. Again, that even when it is present it is far from
+being fully adapted to the performance of its function, may be proved by
+observing that only in rare instances does the scratching leg succeed in
+scratching the place which is being irritated. The movements are made
+more or less at random, and as often as not the foot fails to touch the
+body at any place at all. Hence, although we have a "prophecy" of a
+reflex action well designed for the discharge of a particular function,
+at present the machinery is not sufficiently perfected for the adequate
+discharge of that function. In this important respect it differs from
+the otherwise closely analogous reflex action of the frog, whereby the
+foot of the hind leg is enabled to localize with precision a seat of
+irritation on the side of the body. But this beautiful mechanism in the
+frog cannot have sprung into existence ready formed at any historical
+moment in the past history of the phyla. It must have been the subject
+of a more or less prolonged evolution, in some stage of which it must
+presumably have resembled the now nascent scratching reflex of the dog,
+in making merely abortive attempts at localizing the seat of
+irritation--supposing, of course, that some physiologist had been there
+to try the experiment by first removing the brain. Now, even if one
+could imagine it to be, either in the frog or in the dog, a matter of
+selective importance that so exceedingly refined a mechanism should have
+been developed for the sole purpose of inhibiting the bites of
+parasites--which in every normal animal would certainly be discharged by
+an _intentional_ performance of the movements in question,--even if, in
+order to save an hypothesis at all costs, we make so violent a
+supposition as this, still we should do so in vain. For it would still
+remain undeniably certain that the reflex mechanism is _not_ of any
+selective value. Even now the mechanism in the dog is not sufficiently
+precise to subserve the only function which occasionally and abortively
+it attempts to perform. Thus it has all the appearance of being but an
+imitating shadow of certain neuro-muscular adjustments, which have been
+habitually performed in the canine phyla by a volitional response to
+cutaneous irritation. Were it necessary, this argument might be
+strengthened by observing that the reflex action is positively
+_improved_ by removal of the brain.
+
+The second example of a nascent reflex in dogs which I have to mention
+is as follows.
+
+Goltz found that his brainless dogs, when wetted with water, would shake
+themselves as dry as possible, in just the same way as normal dogs will
+do under similar circumstances. This, of course, proves that the shaking
+movements may be performed by a reflex mechanism, which can have no
+other function to perform in the organization of a dog, and which,
+besides being of a highly elaborate character, will respond only to a
+very special kind of stimulation. Now, here also I find that the
+mechanism is congenital, or not acquired by individual experience. For
+the puppies on which I experimented were kept indoors from the time of
+their birth--so as never to have had any experience of being wetted by
+rain, &c.--till they were old enough to run about with a full power of
+co-ordinating their general movements. If these young animals were
+suddenly plunged into water, the shock proved too great: they would
+merely lie and shiver. But if their feet alone were wetted, by being
+dipped in a basin of water, the puppies would soon afterwards shake
+their heads in the peculiar manner which is required for shaking water
+off the ears, and which in adult dogs constitutes the first phase of a
+general shaking of the whole body.
+
+Here, then, we seem to have good evidence of all the same facts which
+were presented in the case of the scratching reflex. In the first
+place, co-adaptation is present in a very high degree, because this
+shaking reflex in the dog, unlike the skin-twitching reflex in the
+horse, does not involve only a single muscle, or even a single group of
+muscles; it involves more or less the co-ordinated activity of many
+voluntary muscles all over the body. Such, at any rate, is the case when
+the action is performed by the intelligent volition of an adult dog; and
+if a brainless dog, or a young puppy, does not perform it so extensively
+or so vigorously, this only goes to prove that the reflex has not yet
+been sufficiently developed to serve as a substitute for intelligent
+volition--i.e. that it is _useless_, or a mere organic shadow of the
+really adaptive substance. Again, even if this nascent reflex had been
+so far developed as to have been capable of superseding voluntary
+action, still we may fairly doubt whether it could have proved of
+selective value. For it is questionable whether the immediate riddance
+of water after a wetting is a matter of life and death to dogs in a
+state of nature. Moreover, even if it were, every individual dog would
+always have got rid of the irritation, and so of the danger, by means of
+a _voluntary_ shake--with the double result that natural selection has
+never had any opportunity of gradually building up a special reflex
+mechanism for the purpose of securing a shake, and that the canine race
+have not had to wait for any such unnecessary process. Lastly, such a
+process, besides being unnecessary, must surely have been, under any
+circumstances, impossible. For even if we were to suppose--again for the
+sake of saving an hypothesis at any cost--that the presence of a
+fully-formed shaking reflex is of selective value in the struggle for
+existence, it is perfectly certain that all the stages through which the
+construction of so elaborate a mechanism must have passed could not have
+been, under any circumstances, of any such value.
+
+But, it is needless to repeat, according to the hypothesis of
+use-inheritance, there is no necessity to suppose that these incipient
+reflex mechanisms _are_ of any value. If function produces structure in
+the race as it does in the individual, the voluntary and frequently
+repeated actions of scratching and shaking may very well have led to an
+organic integration of the neuro-muscular mechanisms concerned. Their
+various parts having been always co-ordinated for the performance of
+these actions by the intelligence of innumerable dogs in the past, their
+co-adapted activity in their now automatic responses to appropriate
+stimuli presents no difficulty. And the consideration that neither in
+their prospectively more fully developed condition, nor, _a fortiori_,
+in their present and all previous stages of evolution, can these reflex
+mechanisms be regarded as presenting any selective--or even so much as
+any adaptive--value, is neither more nor less than the theory of
+use-inheritance would expect.
+
+Thus, with regard to the phenomena of reflex action in general, all the
+facts are such as this theory requires, while many of the facts are such
+as the theory of natural selection alone cannot conceivably explain.
+Indeed, it is scarcely too much to say, that most of the facts are such
+as directly contradict the latter theory in its application to them.
+But, be this as it may, at present there are only two hypotheses in the
+field whereby to account for the facts of adaptive evolution. One of
+these hypotheses is universally accepted, and the only question is
+whether we are to regard it as _alone_ sufficient to explain _all_ the
+facts. The other hypothesis having been questioned, we can test its
+validity only by finding cases which it is fully capable of explaining,
+and which do not admit of being explained by its companion hypothesis. I
+have endeavoured to show that we have a large class of such cases in the
+domain of reflex action, and shall next endeavour to show that there is
+another large class in the domain of instinct.
+
+       *       *       *       *       *
+
+If instinct be, as Professor Hering, Mr. Samuel Butler, and others have
+argued, "hereditary habit"--i. e. if it comprises an element of
+transmitted experience--we at once find a complete explanation of many
+cases of the display of instinct which otherwise remain inexplicable.
+For although a large number--or even, as I believe, a large majority--of
+instincts are explicable by the theory of natural selection alone, or by
+supposing that they were gradually developed by the survival of
+fortuitous variations in the way of advantageous psychological
+peculiarities, this only applies to comparatively simple instincts, such
+as that of a protectively coloured animal exhibiting a preference for
+the surroundings which it resembles, or even adopting attitudes in
+imitation of objects which occur in such surroundings. But in all cases
+where instincts become complex and refined, we seem almost compelled to
+accept Darwin's view that their origin is to be sought in consciously
+intelligent adjustments on the part of ancestors.
+
+Thus, to give only one example, a species of Sphex preys upon
+caterpillars, which it stings in their nerve-centres for the purpose of
+paralyzing, without killing them. The victims, when thus rendered
+motionless, are then buried with the eggs of the Sphex, in order to
+serve as food for her larvae which subsequently develop from these eggs.
+Now, in order thus to paralyze a caterpillar, the Sphex has to sting it
+successively in nine minute and particular points along the ventral
+surface of the animal--and this the Sphex unerringly does, to the
+exclusion of all other points of the caterpillar's anatomy. Well, such
+being the facts--according to M. Fabre, who appears to have observed
+them carefully--it is conceivable enough, as Darwin supposed[48], that
+the ancestors of the Sphex, being like many other hymenopterous insects
+highly intelligent, should have observed that on stinging caterpillars
+in these particular spots a greater amount of effect was produced than
+could be produced by stinging them anywhere else; and, therefore, that
+they habitually stung the caterpillars in these places only, till, in
+course of time, this originally intelligent habit became by heredity
+instinctive. But now, on the other hand, if we exclude the possibility
+of this explanation, it appears to me incredible that such an instinct
+should ever have been evolved at all; for it appears to me incredible
+that natural selection, unaided by originally intelligent action, could
+ever have developed such an instinct out of merely fortuitous
+variations--there being, by hypothesis, nothing to _determine_
+variations of an insect's mind in the direction of stinging caterpillars
+only in these nine intensely localized spots[49].
+
+    [48] For details of his explanation of this particular case, for
+         which I particularly inquired, see _Mental Evolution in
+         Animals_, pp. 301-2.
+
+    [49] Note B.
+
+Again, there are not a few instincts which appear to be wholly useless
+to their possessors, and others again which appear to be even
+deleterious. The dusting over of their excrement by certain
+freely-roaming carnivora; the choice by certain herbivora of particular
+places on which to void their urine, or in which to die; the howling of
+wolves at the moon; purring of cats, &c., under pleasurable emotion; and
+sundry other hereditary actions of the same apparently unmeaning kind,
+all admit of being readily accounted for as useless habits originally
+acquired in various ways, and afterwards perpetuated by heredity,
+because not sufficiently deleterious to have been stamped out by natural
+selection[50]. But it does not seem possible to explain them by survival
+of the fittest in the struggle for existence.
+
+    [50] For fuller treatment see _Mental Evolution in Animals_, pp.
+         274-285, 378-379, 381-383.
+
+Finally, in the case of our own species, it is self-evident that the
+aesthetic, moral, and religious instincts admit of a natural and easy
+explanation on the hypothesis of use-inheritance, while such is by no
+means the case if that hypothesis is rejected. Our emotions of the
+ludicrous, of the beautiful, and of the sublime, appear to be of the
+nature of hereditary instincts; and be this as it may, it would further
+appear that, whatever else they may be, they are certainly not of a
+life-preserving character. And although this cannot be said of the
+moral sense when the theory of natural selection is extended from the
+individual to the tribe, still, when we remember the extraordinary
+complexity and refinement to which they have attained in civilized man,
+we may well doubt whether they can have been due to natural selection
+alone. But space forbids discussion of this large and important question
+on the present occasion. Suffice it therefore to say, that I doubt not
+Weismann himself would be the first to allow that his theory of heredity
+encounters greater difficulties in the domain of ethics than in any
+other--unless, indeed, it be that of religion[51].
+
+    [51] For an excellent essay on the deleterious character of early
+         forms of religion from a biological point of view, see the Hon.
+         Lady Welby, _An Apparent Paradox in Mental Evolution_ (Journ.
+         Anthrop. Inst. May 1891).
+
+       *       *       *       *       *
+
+I have now given a brief sketch of the indirect evidence in favour of
+the so-called Lamarckian factors, in so far as this appears fairly
+deducible from the facts of reflex action and of instinct. It will now
+be my endeavour to present as briefly what has to be said against this
+evidence.
+
+As previously observed, the facts of reflex action have not been
+hitherto adduced in the present connexion. This has led me to occupy
+considerably more space in the treatment of them than those of instinct.
+On this account, also, there is here nothing to quote, or to consider,
+_per contra_. On the other hand, however, Weismann has himself dealt
+with the phenomena of instinct in animals, though not, I think, in
+man--if we except his brilliant essay on music. Therefore let us now
+begin this division of our subject by briefly stating, and considering,
+what he has said upon the subject.
+
+The answer of Weismann to difficulties which arise against the
+ultra-Darwinian theory in the domain of instinct, is as follows:--
+
+     "The necessity for extreme caution in appealing to the supposed
+     hereditary effects of use, is well shown in the case of those
+     numerous instincts which only come into play once in a life-time,
+     and which do not therefore admit of improvement by practice. The
+     queen-bee takes her nuptial flight only once, and yet how many and
+     complex are the instincts and the reflex mechanisms which come into
+     play on that occasion. Again, in many insects the deposition of
+     eggs occurs but once in a life-time, and yet such insects always
+     fulfil the necessary conditions with unfailing accuracy[52]."
+
+    [52] _Essays_, i. p. 93.
+
+But in this rejoinder the possibility is forgotten, that although such
+actions are _now_ performed only once in the individual life-time,
+_originally_--i.e. when the instincts were being developed in a remote
+ancestry--they may have been performed on many frequent and successive
+occasions during the individual life-time. In all the cases quoted by
+Weismann, instincts of the kind in question bear independent evidence of
+high antiquity, by occurring in whole genera (or even families), by
+being associated with peculiar and often highly evolved structures
+required for their performance, and so on. Consequently, in these cases
+ample time has been allowed for subsequent changes of habit, and of
+seasonal alterations with respect to propagation--both these things
+being of frequent and facile occurrence among animals of all kinds, even
+within periods which fall under actual observation. Nevertheless, I do
+not question that there are instinctive activities which, as far as we
+are able to see, can never have been performed more than once in each
+individual life-time[53]. The fact, however, only goes to show what is
+fully admitted--that some instincts (and even highly complex instincts)
+have apparently been developed by natural selection alone. Which, of
+course, is not equivalent to showing that all instincts must have been
+developed by natural selection alone. The issue is not to be debated on
+general grounds like this, but on those of particular cases. Even if it
+were satisfactorily proved that the instincts of a queen-bee have been
+developed by natural selection, it would not thereby be proved that such
+has been the case with the instincts of a Sphex wasp. One can very well
+understand how the nuptial flight of the former, with all its associated
+actions, may have been brought about by natural selection alone; but
+this does not help us to understand how the peculiar instincts of the
+latter can have been thus caused.
+
+    [53] See _Mental Evolution in Animals_, pp. 377-8.
+
+Strong evidence in favour of Weismann's views does, however, at first
+sight seem to be furnished by social hymenoptera in other respects. For
+not only does the queen present highly specialized and altogether
+remarkable instincts; but the neuters present totally different and even
+still more remarkable instincts--which, moreover, are often divided into
+two or more classes, corresponding with the different "castes." Yet the
+neuters, being barren females, never have an opportunity of bequeathing
+their instincts to progeny. Thus it appears necessary to suppose that
+the instincts of all the different castes of neuters are latent in the
+queen and drones, together with the other instincts which are patent in
+both. Lastly, it seems necessary to suppose that all this wonderful
+organization of complex and segregated instincts must have been built up
+by natural selection acting exclusively on the queens and drones--seeing
+that these exercise their own instincts only once in a life-time, while,
+as just observed, the neuters cannot possibly bequeath their individual
+experience to progeny. Obviously, however, natural selection must here
+be supposed to be operating at an immense disadvantage; for it must have
+built up the often diverse and always complex instincts of neuters, not
+directly, but indirectly through the queens and drones, which never
+manifest any of these instincts themselves.
+
+Now Darwin fully acknowledged the difficulty of attributing these
+results to the unaided influence of natural selection; but the fact of
+neuter insects being unable to propagate seemed to him to leave no
+alternative. And so it seems to Weismann, who accordingly quotes these
+instincts in support of his views. And so it seemed to me, until my work
+on _Animal Intelligence_ was translated into French, and an able Preface
+was supplied to that translation by M. Perrier. In this Preface it is
+argued that we are not necessarily obliged to exclude the possibility of
+Lamarckian principles having operated in the original formation of these
+instincts. On the contrary, if such principles ever operate at all,
+Perrier shows that here we have a case where it is virtually certain
+that they must have operated. For although neuter insects are now unable
+to propagate, their organization indicates--if it does not actually
+prove--that they are descended from working insects which were able to
+propagate. Thus, in all probability, what we now call a "hive" was
+originally a society of sexually mature insects, all presenting the same
+instincts, both as to propagation and to co-operation. When these
+instincts, thus common to all individuals composing the hive, had been
+highly perfected, it became of advantage in the struggle for existence
+(between different hives or communities) that the functions of
+reproduction should devolve more upon some individuals, while those of
+co-operation should devolve more upon others. Consequently, this
+division of labour began, and gradually became complete, as we now find
+it in bees and ants. Perrier sustains the hypothesis thus briefly
+sketched by pointing to certain species of social hymenoptera where we
+may actually observe different stages of the process--from cases where
+all the females of the hive are at the same time workers and breeders,
+up to the cases where the severance between these functions has become
+complete. Therefore, it seems to me, it is no longer necessary to
+suppose that in these latter cases all the instincts of the (now) barren
+females can only have been due to the unaided influence of natural
+selection.
+
+Nevertheless, although I think that Perrier has made good his position
+thus far, that his hypothesis fails to account for some of the instincts
+which are manifested by neuter insects, such as those which, so far as I
+can see, must necessarily be supposed to have originated after the
+breeding and working functions had become separated--seeing that they
+appear to have exclusive reference to this peculiar state of matters.
+Possibly, however, Perrier might be able to meet each of these
+particular instincts, by showing how they could have arisen out of
+simpler beginnings, prior to the separation of the two functions in
+question. There is no space to consider such possibilities in detail;
+but, until this shall have been done, I do not think we are entitled to
+conclude that the phenomena of instinct as presented by neuter insects
+are demonstrably incompatible with the doctrines of Lamarck--or, that
+these phenomena are available as a logical proof of the unassisted
+agency of natural selection in the case of instincts in general[54].
+
+    [54] [See H. Spencer, _The Inadequacy of Natural Selection, A
+         Rejoinder to Professor Weismann_, Contemp. Rev. 1893; and
+         _Weismannism once more_, Ibid. Oct. 1894; Weismann, _The
+         All-sufficiency of Natural Selection_, Ibid. 1893; and _The
+         Effect of External Influences upon Development_, "Romanes
+         Lecture" 1894: also _Neuter Insects and Lamarckism_, W. Platt
+         Ball, Natural Science, Feb. 1894, and _Neuter Insects and
+         Darwinism_, J. T. Cunningham, Ibid. April 1894. C. Ll. M.]
+
+
+(B.)
+_Inherited Effects of Use and of Disuse._
+
+There is no doubt that Darwin everywhere attaches great weight to this
+line of evidence. Nevertheless, in my opinion, there is equally little
+doubt that, taken by itself, it is of immeasurably less weight than
+Darwin supposed. Indeed, I quite agree with Weismann that the whole of
+this line of evidence is practically worthless; and for the following
+reasons.
+
+The evidence on which Darwin relied to prove the inherited effects of
+use and disuse was derived from his careful measurements of the increase
+or decrease which certain bones of our domesticated animals have
+undergone, as compared with the corresponding bones of ancestral stocks
+in a state of nature. He chose domesticated animals for these
+investigations, because, while yielding unquestionable cases of
+increased or diminished use of certain organs over a large number of
+sequent generations, the results were not complicated by the possible
+interference of natural selection on the one hand, or by that of the
+economy of nutrition on the other. For "with highly-fed domesticated
+animals there seems to be no economy of growth, or any tendency to the
+elimination of superfluous details[55];" seeing that, among other
+considerations pointing in the same direction, "structures which are
+rudimentary in the parent species, sometimes become partially
+re-developed in our domesticated productions[56]."
+
+    [55] _Variation of Plants and Animals_, vol. ii. p. 289.
+
+    [56] _Ibid._ p. 346.
+
+The method of Darwin's researches in this connexion was as follows.
+Taking, for example, the case of ducks, he carefully weighed and
+measured the wing-bones and leg-bones of wild and tame ducks; and he
+found that the wing-bones were smaller, while the leg-bones were larger,
+in the tame than in the wild specimens. These facts he attributed to
+many generations of tame ducks using their wings less, and their legs
+more, than was the case with their wild ancestry. Similarly he compared
+the leg-bones of wild rabbits with those of tame ones, and so forth--in
+all cases finding that where domestication had led to increased use of a
+part, that part was larger than in the wild parent stock; while the
+reverse was the case with parts less used. Now, although at first sight
+these facts certainly do seem to yield good evidence of the inherited
+effects of use and disuse, they are really open to the following very
+weighty objections.
+
+First of all, there is no means of knowing how far the observed effects
+may have been due to increased or diminished use during only the
+individual life-time of each domesticated animal. Again, and this is a
+more important point, in all Darwin's investigations the increase or
+decrease of a part was estimated, not by directly comparing, say the
+wing-bones of a domesticated duck with the wing-bones of a wild duck,
+but by comparing the _ratio_ between the wing and leg bones of a tame
+duck with the _ratio_ between the wing and leg bones of a wild duck.
+Consequently, if there be any reason to doubt the supposition that a
+really inherited decrease in the size of a part thus estimated is due to
+the inherited effects of disuse, such a doubt will also extend to the
+evidence of increased size being due to the inherited effects of use.
+Now there is the gravest possible doubt lying against the supposition
+that any really inherited decrease in the size of a part is due to the
+inherited effects of disuse. For it may be--and, at any rate to some
+extent, must be--due to another principle, which it is strange that
+Darwin should have overlooked. This is the principle which Weismann has
+called Panmixia, and which cannot be better expressed than in his own
+words:--
+
+     "A goose or a duck must possess strong powers of flight in the
+     natural state, but such powers are no longer necessary for
+     obtaining food when it is brought into the poultry-yard; so that a
+     rigid selection of individuals with well-developed wings at once
+     ceases among its descendants. Hence, in the course of generations,
+     a deterioration of the organs of flight must necessarily
+     ensue[57]."
+
+    [57] _Essays_, i. p. 90.
+
+Or, to state the case in another way: if any structure which was
+originally built up by natural selection on account of its use, ceases
+any longer to be of so much use, in whatever degree it ceases to be of
+use, in that degree will the premium before set upon it by natural
+selection be withdrawn. And the consequence of this withdrawal of
+selection as regards that particular part will be to allow the part to
+degenerate in successive generations. Such is the principle which
+Weismann calls Panmixia, because, by the withdrawal of selection from
+any particular part, promiscuous breeding ensues with regard to that
+part. And it is easy to see that this principle must be one of very
+great importance in nature; because it must necessarily come into
+operation in all cases where any structure or any instinct has, through
+any change in the environment or in the habits of a species, ceased to
+be useful. It is likewise easy to see that its effect must be the same
+as that which was attributed by Darwin to the inherited effect of
+disuse; and, therefore, that the evidence on which he relied in proof of
+the inherited effects both of use and of disuse is vitiated by the fact
+that the idea of Panmixia did not occur to him.
+
+Here, however, it may be said that the idea first occurred to me[58]
+just after the publication of the last edition of the _Origin of
+Species_. I called the principle the Cessation of Selection--which I
+still think a better, because a more descriptive, term than Panmixia;
+and at that time it appeared to me, as it now appears to Weismann,
+entirely to supersede the necessity of supposing that the effect of
+disuse is ever inherited in any degree at all. Thus it raised the whole
+question as to the admissibility of Lamarckian principles in general; or
+the question on which we are now engaged touching the possible
+inheritance of acquired, as distinguished from congenital, characters.
+But on discussing the matter with Mr. Darwin, he satisfied me that the
+larger question was not to be so easily closed. That is to say, although
+he fully accepted the principle of the Cessation of Selection, and as
+fully acknowledged its obvious importance, he convinced me that there
+was independent evidence for the transmission of acquired characters,
+sufficient in amount to leave the general structure of his previous
+theory unaffected by what he nevertheless recognized as a factor which
+must necessarily be added. All this I now mention in order to show that
+the issue which Weismann has raised since Darwin's death was expressly
+contemplated during the later years of Darwin's life. For if the idea of
+Panmixia--in the absence of which Weismann's entire system would be
+impossible--had never been present to Darwin's mind, we should have been
+left in uncertainty how he would have regarded this subsequent revolt
+against what are generally called the Lamarckian principles[59].
+
+    [58] _Nature_, vol. ix. pp. 361-2, 440-1; and vol. x. p. 164.
+
+    [59] Appendix I.
+
+Moreover, in this connexion we must take particular notice that the
+year after I had published these articles on the Cessation of Selection,
+and discussed with Mr. Darwin the bearing of this principle on the
+question of the transmission of acquired characters, Mr. Galton followed
+with his highly important essay on Heredity. For in this essay Mr.
+Galton fully adopted the principle of the Cessation of Selection, and
+was in consequence the first publicly to challenge the Lamarckian
+principles--pointing out that, if it were thus possible to deny the
+transmission of acquired characters _in toto_, "we should be relieved
+from all further trouble"; but that, if such characters are transmitted
+"in however faint a degree, a complete theory of heredity must account
+for them." Thus the question which, in its revived condition, is now
+attracting so much attention, was propounded in all its parts some
+fifteen or sixteen years ago; and no additional facts or new
+considerations of any great importance bearing upon the subject have
+been adduced since that time. In other words, about a year after my own
+conversations with Mr. Darwin, the whole matter was still more
+effectively brought before his notice by his own cousin. And the result
+was that he still retained his belief in the Lamarckian factors of
+organic evolution, even more strongly than it was retained either by Mr.
+Galton or myself[60].
+
+    [60] For a fuller statement of Mr. Galton's theory of Heredity, and
+         its relation to Weismann's, see _An Examination of
+         Weismannism_.
+
+We have now considered the line of evidence on which Darwin chiefly
+relied in proof of the transmissibility of acquired characters; and it
+must be allowed that this line of evidence is practically worthless.
+What he regarded as the inherited effects of use and of disuse may be
+entirely due to the cessation of selection in the case of our
+domesticated animals, combined with an active _reversal_ of selection in
+the case of natural species. And in accordance with this view is the
+fact that the degeneration of disused parts proceeds much further in the
+case of wild species than it does in that of domesticated varieties. For
+although it may be said that in the case of wild species more time has
+been allowed for a greater accumulation of the inherited effects of
+disuse than can have been the case with domesticated varieties, the
+alternative explanation is at least as probable--that in the case of
+wild species the merely negative, or passive, influence of the
+_cessation_ of selection has been continuously and powerfully assisted
+by the positive, or active, influence of the _reversal_ of selection,
+through economy of growth and the general advantage to be derived from
+the abolition of useless parts[61].
+
+    [61] For a fuller explanation of the important difference between
+         the mere cessation and the actual reversal of selection, see
+         Appendix I.
+
+The absence of any good evidence of this direct kind in favour of
+use-inheritance will be rendered strikingly apparent to any one who
+reads a learned and interesting work by Professor Semper[62]. His object
+was to show the large part which he believed to have been played by
+external conditions of life in directly modifying organic types--or, in
+other words, of proving that side of Lamarckianism which refers to the
+immediate action of the environment, whether with or without the
+co-operation of use-inheritance and natural selection. Although Semper
+gathered together a great array of facts, the more carefully one reads
+his book the more apparent does it become that no single one of the
+facts is in itself conclusive evidence of the transmission to progeny of
+characters which are acquired through use-inheritance or through direct
+action of the environment. Every one of the facts is susceptible of
+explanation on the hypothesis that the principle of natural selection
+has been the only principle concerned. This, however, it must be
+observed, is by no means equivalent to proving that characters thus
+acquired are not transmitted. As already pointed out, it is
+impracticable with species in a state of nature to dissociate the
+distinctively Darwinian from the possibly Lamarckian factors; so that
+even if the latter are largely operative, we can only hope for direct
+evidence of the fact from direct experiments on varieties in a state of
+domestication. To this branch of our subject, therefore, we will now
+proceed.
+
+    [62] _Animal Life_, International Scientific Series, vol. xxxi.
+
+
+
+
+CHAPTER IV.
+
+CHARACTERS AS HEREDITARY AND ACQUIRED
+(_continued_).
+
+
+(C.)
+_Experimental Evidence in favour of the Inheritance of Acquired
+Characters._
+
+
+Notwithstanding the fact already noticed, that no experiments have
+hitherto been published with reference to the question of the
+transmission of acquired characters[63], there are several researches
+which, with other objects in view, have incidentally yielded seemingly
+good evidence of such transmission. The best-known of these
+researches--and therefore the one with which I shall begin--is that of
+Brown-Sequard touching the effects of certain injuries of the nervous
+system in guinea-pigs.
+
+    [63] The experiments of Galton and Weismann upon this subject are
+         nugatory, as will be shown later on. But since the above was
+         written an important research has been published by Mr.
+         Cunningham, of the Marine Biological Association. For a full
+         account I must refer the reader to his forthcoming paper in the
+         _Philosophical Transactions_. The following is his own
+         statement of the principal results:--
+
+         "A case which I have myself recently investigated
+         experimentally seems to me to support very strongly the theory
+         of the inheritance of acquired characters, I have shown that in
+         normal flat-fishes, if the lower side be artificially exposed
+         to light for a long time, pigmentation is developed on that
+         side; but when the exposure is commenced while the specimens
+         are still in process of metamorphosis, when pigment-cells are
+         still present on the lower side, the action of light does not
+         prevent the disappearance of these pigment-cells. They
+         disappear as in individuals living under normal conditions, but
+         after prolonged exposure pigment-cells reappear. The first fact
+         proves that the disappearance of the pigment-cells from the
+         lower side in the metamorphosis is an hereditary character, and
+         not a change produced in each individual by the withdrawal of
+         the lower side from the action of light. On the other hand, the
+         experiments show that the absence of pigment-cells from the
+         lower side throughout life is due to the fact that light does
+         not act upon that side, for, when it is allowed to act,
+         pigment-cells appear. It seems to me the only reasonable
+         conclusion from these facts is, that the disappearance of
+         pigment-cells was originally due to the absence of light, and
+         that this change has now become hereditary. The pigment-cells
+         produced by the action of light on the lower side are in all
+         respects similar to those normally present on the upper side of
+         the fish. If the disappearance of the pigment-cells were due
+         entirely to a variation of the germ-plasm, no external
+         influence could cause them to reappear, and, on the other hand,
+         if there were no hereditary tendency, the colouration of the
+         lower side of the flat-fish when exposed would be rapid and
+         complete."--_Natural Science_, Oct. 1893.
+
+During a period of thirty years Brown-Sequard bred many thousands of
+guinea-pigs as material for his various researches; and in those whose
+parents had not been operated upon in the ways to be immediately
+mentioned, he never saw any of the peculiarities which are about to be
+described. Therefore the hypothesis of coincidence, at all events, must
+be excluded. The following is his own summary of the results with which
+we are concerned:--
+
+     1st. Appearance of epilepsy in animals born of parents which had
+     been rendered epileptic by an injury to the spinal cord.
+
+     2nd. Appearance of epilepsy also in animals born of parents which
+     had been rendered epileptic by section of the sciatic nerve.
+
+     3rd. A change in the shape of the ear in animals born of parents in
+     which such a change was the effect of a division of the cervical
+     sympathetic nerve.
+
+     4th. Partial closure of the eyelids in animals born of parents in
+     which that state of the eyelids had been caused either by section
+     of the cervical sympathetic nerve, or the removal of the superior
+     cervical ganglion.
+
+     5th. Exophthalmia in animals born of parents in which an injury to
+     the restiform body had produced that protrusion of the eyeball.
+     This interesting fact I have witnessed a good many times, and seen
+     the transmission of the morbid state of the eye continue through
+     four generations. In these animals, modified by heredity, the two
+     eyes generally protruded, although in the parents usually only one
+     showed exophthalmia, the lesion having been made in most cases only
+     on one of the corpora restiformia.
+
+     6th. Haematoma and dry gangrene of the ears in animals born of
+     parents in which these ear-alterations had been caused by an injury
+     to the restiform body near the nib of the calamus.
+
+     7th. Absence of two toes out of the three of the hind leg, and
+     sometimes of the three, in animals whose parents had eaten up their
+     hind-leg toes which had become anaesthetic from a section of the
+     sciatic nerve alone, or of that nerve and also of the crural.
+     Sometimes, instead of complete absence of the toes, only a part of
+     one or two or three was missing in the young, although in the
+     parent not only the toes but the whole foot were absent (partly
+     eaten off, partly destroyed by inflammation, ulceration, or
+     gangrene.)
+
+     8th. Appearance of various morbid states of the skin and hair of
+     the neck and face in animals born of parents having had similar
+     alterations in the same parts, as effects of an injury to the
+     sciatic nerve.
+
+These results[64] have been independently vouched for by two of
+Brown-Sequard's former assistants--Dr. Dupuy, and the late Professor
+Westphal. Moreover, his results with regard to epilepsy have been
+corroborated also by Obersteiner[65]. I may observe, in passing, that
+this labour of testing Brown-Sequard's statements is one which, in my
+opinion, ought rather to have been undertaken, if not by Weismann
+himself, at all events by some of his followers. Both he and they are
+incessant in their demand for evidence of the transmission of acquired
+characters; yet they have virtually ignored the foregoing very
+remarkable statements. However, be this as it may, all that we have now
+to do is to consider what the school of Weismann has had to say with
+regard to these experiments on the grounds of general reasoning which
+they have thus far been satisfied to occupy.
+
+    [64] For Professor Weismann's statement of and discussion of these
+         results see _Essays_, vol. i. p. 313.
+
+    [65] _Oesterreichische medicinische Jahrbuecher_, 1875, 179.
+
+In view of Obersteiner's corroboration of Brown-Sequard's results
+touching the artificial production and subsequent transmission of
+epilepsy, Weismann accepts the facts, but, in order to save his theory
+of heredity, he argues that the transmission may be due to a traumatic
+introduction of "some unknown microbe" which causes the epilepsy in the
+parent, and, by invading the ova or spermatozoa as the case may be, also
+produces epilepsy in the offspring. Here, of course, there would be
+transmission of epilepsy, but it would not be, technically speaking, an
+hereditary transmission. The case would resemble that of syphilis, where
+the sexual elements remain unaffected as to their congenital endowments,
+although they have been made the vehicles for conveying an organic
+poison to the next generation.
+
+Now it would seem that this suggestion is not, on the face of it, a
+probable one. For "some unknown microbe" it indeed must be, which is
+always on hand to enter a guinea-pig when certain operations are being
+performed on certain parts of the nervous system, but yet will never
+enter when operations of any kind are being effected elsewhere.
+Moreover, Westphal has produced the epilepsy _without any incision_, by
+striking the heads of the animals with a hammer[66]. This latter fact,
+it appears to me, entirely abolishes the intrinsically improbable
+suggestion touching an unknown--and strangely eclectic--microbe.
+However, it is but fair to state what Weismann himself has made of this
+fact. The following is what he says:--
+
+    [66] _Loc. cit._
+
+     "It is obvious that the presence of microbes can have nothing to do
+     with such an attack, but the shock alone must have caused
+     morphological and functional changes in the centre of the pons and
+     medulla oblongata, identical with those produced by microbes in the
+     other cases.... Various stimuli might cause the nervous centres
+     concerned to develop the convulsive attack which, together with its
+     after-effects, we call epilepsy. In Westphal's case, such a
+     stimulus would be given by a powerful mechanical shock (viz. blows
+     on the head with a hammer); in Brown-Sequard's experiments, by the
+     penetration of microbes[67]."
+
+    [67] _Essays_, vol. i. p. 315.
+
+But from this passage it would seem that Weismann has failed to notice
+that in "Westphal's case," as in "Brown-Sequard's experiments," the
+epilepsy was _transmitted to progeny_. That epilepsy may be produced in
+guinea-pigs by a method which does not involve any cutting (i.e.
+possibility of inoculation) would no doubt tend to corroborate the
+suggestion of microbes being concerned in its transmission when it is
+produced by cutting, _if in the former case there were no such
+transmission_. But as there _is_ transmission in _both_ cases, the
+facts, so far as I can see, entirely abolish the suggestion. For they
+prove that even when epilepsy is produced in the parents under
+circumstances which render "it obvious that the presence of microbes can
+have nothing to do with such an attack," the epileptiform condition is
+notwithstanding transmitted to the progeny. What, then, is gained by
+retaining the intrinsically improbable hypothesis of microbes to explain
+the fact of transmission "in Brown-Sequard's experiments," when this
+very same fact is proved to occur without the possibility of microbes
+"in Westphal's case"?
+
+The only other objection with regard to the seeming transmission of
+traumatic epilepsy which Weismann has advanced is, that such epilepsy
+may be produced by two or three very different operations--viz. division
+of the sciatic nerves (one or both), an injury to the spinal cord, and a
+stroke on the head. Does not this show, it is asked, that the epileptic
+condition of guinea-pigs is due to a generally unstable condition of the
+whole nervous system and is not associated with any particular part
+thereof? Well, supposing that such is the case, what would it amount to?
+I cannot see that it would in any way affect the only question in
+debate--viz. What is the significance of the fact that epilepsy is
+_transmitted_? Even if it be but "a tendency," "a disposition," or "a
+diathesis" that is transmitted, it is none the less a case of
+transmission, in fact quite as much so as if the pathological state were
+dependent on the impaired condition of any particular nerve-centre. For,
+it must be observed, there can be no question that it is always produced
+by an operation of _some_ kind. If it were ever to originate in
+guinea-pigs spontaneously, there might be some room for supposing that
+its transmission is due to a congenital tendency running through the
+whole species--although even then it would remain unaccountable, on the
+ultra-Darwinian view, why this tendency should be congenitally
+_increased_ by means of an operation. But epilepsy does not originate
+spontaneously in guinea-pigs; and therefore the criticism in question
+appears to me irrelevant.
+
+Again, it may be worth while to remark that Brown-Sequard's experiments
+do not disprove the possibility of its being some one nerve-centre which
+is concerned in all cases of traumatic epilepsy. And this possibility
+becomes, I think, a probability in view of Luciani's recent experiments
+on the dog. These show that the epileptic condition can be produced in
+this animal by injury to the cortical substance of the hemispheres, and
+is then transmitted to progeny[68]. These experiments, therefore, are of
+great interest--first, as showing that traumatic and transmissible
+epilepsy is not confined to guinea-pigs; and next, as indicating that
+the pathological state in question is associated with the highest
+nerve-centres, which may therefore well be affected by injury to the
+lower centres, or even by section of a large nerve trunk.
+
+    [68] _Les fonctions du Cerveau_, p. 102.
+
+So much, then, with regard to the case of transmitted epilepsy. But now
+it must be noted that, even if Weismann's suggestion touching microbes
+were fully adequate to meet this case, it would still leave unaffected
+those of transmitted protrusion of the eye, drooping of the eyelid,
+gangrene of the ear, absence of toes, &c. In all these cases the facts,
+as stated by Brown-Sequard, are plainly unamenable to any explanation
+which would suppose them due to microbes, or even to any general
+neurotic condition induced by the operation. They are much too definite,
+peculiar, and localized. Doubtless it is on this account that the school
+of Weismann has not seriously attempted to deal with them, but merely
+recommends their repetition by other physiologists[69]. Certain
+criticisms, however, have been urged by Weismann against the
+_interpretation_ of Brown-Sequard's facts as evidence in favour of the
+transmission of acquired characters. It does not appear to me that these
+criticisms present much weight; but it is only fair that we should here
+briefly consider them[70].
+
+    [69] _Essays_, vol. i. p. 82.
+
+    [70] As Weismann gives an excellent abstract of all the alleged
+         facts up to date (_Essays_, vol. i. pp. 319-324), it is
+         needless for me to supply another, further than that which I
+         have already made from Brown-Sequard.
+
+First, with regard to Brown-Sequard's results other than the production
+of transmitted epilepsy, Weismann allows that the hypothesis of microbes
+can scarcely apply. In order to meet these results, therefore, he
+furnishes another suggestion--viz. that where the nervous system has
+sustained "a great shock," the animals are very likely to bear "weak
+descendants, and such as are readily affected by disease." Then, in
+answer to the obvious consideration, "that this does not explain why the
+offspring should suffer from the same disease" as that which has been
+produced in the parents, he adds--"But this does not appear to have been
+by any means invariably the case. For 'Brown-Sequard himself says, the
+changes in the eye of the offspring were of a very variable nature, and
+were only occasionally exactly similar to those observed in the
+parents.'"
+
+Now, this does not appear to me a good commentary. In the first place,
+it does not apply to the other cases (such as the ears and the toes),
+where the changes in the offspring, when they occurred at all, _were_
+exactly similar to those observed in the parents, save that some of them
+occasionally occurred on the _opposite_ side, and frequently also on
+_both_ sides of the offspring. These subordinate facts, however, will
+not be regarded by any physiologist as making against the more ready
+interpretation of the results as due to heredity. For a physiologist
+well knows that homologous parts are apt to exhibit correlated
+variability--and this especially where variations of a congenital kind
+are concerned, and also where there is any reason to suppose that the
+nervous system is involved. Moreover, even in the case of the eye, it
+was always protrusion that was caused in the parent and transmitted to
+the offspring as a result of injuring the restiform bodies of the
+former; while it was always partial closure of the eyelids that was
+caused and transmitted by section of the sympathetic nerve, or removal
+of the cervical ganglia. Therefore, if we call such effects "diseases,"
+surely it _was_ "the same disease" which in each case appeared in the
+parents and reappeared in their offspring. Again, the "diseases" were so
+peculiar, definite, and localized, that I cannot see how they can be
+reasonably ascribed to a general nervous "shock." Why, for instance, if
+this were the case, should a protruding eye never result from removal
+of the cervical ganglia, a drooping eyelid from a puncture of the
+restiform body, a toeless foot from either or both of these operations,
+and so on? In view of such considerations I cannot deem these
+suggestions touching "microbes" and "diseases" as worthy of the
+distinguished biologist from whom they emanate.
+
+Secondly, Weismann asks--How can we suppose these results to be
+instances of the transmission of acquired characters, when from
+Brown-Sequard's own statement of them it appears that the mutilation
+itself was not inherited, but only its effects? Neither in the case of
+the sciatic nerve, the sympathetic nerve, the cervical ganglion, nor the
+restiform bodies, was there ever any trace of transmitted injury in the
+corresponding parts of the offspring; so that, if the "diseases" from
+which they suffered be regarded as hereditary, we have to suppose that a
+consequence was in each case transmitted without the transmission of its
+cause, which is absurd. But I do not think that this criticism can be
+deemed of much weight by a physiologist as distinguished from a
+naturalist. For nothing is more certain to a student of physiology, in
+any of its branches, than that negative evidence, if yielded by the
+microscope alone, is most precarious. Therefore it does not need a
+_visible_ change in the nervous system to be present, in order that the
+part affected should be functionally weak or incapable: pathology can
+show numberless cases of nerve-disorder the "structural" causes of which
+neither the scalpel nor the microscope can detect. So that, if any
+peculiar form of nerve-disorder is transmitted to progeny, and if it be
+certain that it has been caused by injury to some particular part of
+the nervous system, I cannot see that there is any reason to doubt the
+transmission of a nervous lesion merely on the ground that it is not
+visibly discernible. Of course there may be other grounds for doubting
+it; but I am satisfied that this ground is untenable. Besides, it must
+be remembered, as regards the particular cases in question, that no one
+has thus far investigated the histology of the matter by the greatly
+improved methods which are now at our disposal.
+
+       *       *       *       *       *
+
+I have now considered all the criticisms which have been advanced
+against what may be called the Lamarckian interpretation of
+Brown-Sequard's results; and I think it will be seen that they present
+very little force--even if it can be seen that they present any force at
+all. But it must be remembered that this is a different thing from
+saying that the Lamarckian interpretation is the true one. The facts
+alleged are, without question, highly peculiar; and, on this account
+alone, Brown-Sequard's interpretation of them ought to be deemed
+provisional. Hence, although as yet they have not encountered any valid
+criticism from the side of ultra-Darwinian theory, I do not agree with
+Darwin that, on the supposition of their truth as facts, they furnish
+positive proof of the transmission of acquired characters. Rather do I
+agree with Weismann that further investigation is needed in order to
+establish such an important conclusion on the basis of so unusual a
+class of facts. This further investigation, therefore, I have
+undertaken, and will now state the results.
+
+Although this work was begun over twenty years ago, and then yielded
+negative results, it was only within the last decade that I resumed it
+more systematically, and under the tutelage of Brown-Sequard himself.
+During the last two years, however, the experiments have been so much
+interrupted by illness that even now the research is far from complete.
+Therefore I will here confine myself to a tabular statement of the
+results as far as they have hitherto gone, on the understanding that, in
+so far as they are negative or doubtful, I am not yet prepared to
+announce them as final.
+
+We may take Brown-Sequard's propositions in his own order, as already
+given on page 104.
+
+     1st. Appearance of epilepsy in animals born of parents which had
+     been rendered epileptic by an injury to the spinal cord.
+
+     2nd. Appearance of epilepsy also in animals born of parents which
+     had been rendered epileptic by section of the sciatic nerve.
+
+I did not repeat these experiments with a view to producing epilepsy,
+because, as above stated, they had been already and sufficiently
+corroborated in this respect. But I repeated many times the experiments
+of dividing the sciatic nerve for the purpose of testing the statements
+made later on in paragraphs 7 and 8, and observed that it almost always
+had the effect of producing epilepsy in the animal thus operated
+upon--and this of a peculiar kind, the chief characteristics of which
+may here be summarized. The epileptiform habit does not supervene until
+some considerable time after the operation; it is then transitory,
+lasting only for some weeks or months. While the habit endures the fits
+never occur spontaneously, but only as a result of irritating a small
+area of skin behind the ear on the same side of the body as that on
+which the sciatic nerve had been divided. Effectual irritation may be
+either mechanical (such as gentle pinching), electrical, or, though less
+certainly, thermal. The area of skin in question, soon after the
+epileptiform habit supervenes, and during all the time that it lasts,
+swarms with lice of the kind which infest guinea-pigs--i.e. the lice
+congregate in this area, on account, I think, of the animal being there
+insensitive, and therefore not disturbing its parasites in that
+particular spot; otherwise it would presumably throw itself into fits by
+scratching that spot. On removing the skin from the area in question, no
+kind or degree of irritation supplied to the subjacent tissue has any
+effect in producing a fit. A fit never lasts for more than a very few
+minutes, during which the animal is unconscious and convulsed, though
+not with any great violence. The epileptiform habit is but rarely
+transmitted to progeny. Most of these observations are in accordance
+with those previously made by Brown-Sequard, and also by others who have
+repeated his experiments under this heading. I can have no doubt that
+the injury of the sciatic nerve or spinal cord produces a change in some
+of the cerebral centres, and that it is this change--whatever it is and
+in whatever part of the brain it takes place--which causes the
+remarkable phenomena in question.
+
+     3rd. A change in the shape of the ear in animals born of parents in
+     which such a change was the effect of a division of the cervical
+     sympathetic nerve.
+
+     4th. Partial closure of the eyelids in animals born of parents in
+     which that state of the eyelids had been caused either by section
+     of the cervical sympathetic nerve, or the removal of the superior
+     cervical ganglion.
+
+I have not succeeded in corroborating these results. It must be added,
+however, that up to the time of going to press my experiments on this,
+the easiest branch of the research, have been too few fairly to prove a
+negative.
+
+     5th. Exophthalmia in animals born of parents in which an injury to
+     the restiform body had produced that protrusion of the eyeball....
+     In these animals, modified by heredity, the two eyes generally
+     protruded, although in the parents usually only one showed
+     exophthalmia, the lesion having been made in most cases only on one
+     of the corpora restiformia.
+
+I have fully corroborated the statement that injury to a particular spot
+of the restiform body is quickly followed by a marked protrusion of the
+eyeball on the same side. I have also had many cases in which some of
+the progeny of parents thus affected have shown considerable protrusion
+of the eyeballs on both sides, and this seemingly abnormal protrusion
+has been occasionally transmitted to the next generation. Nevertheless,
+I am far from satisfied that this latter fact is anything more than an
+accidental coincidence. For I have never seen the so-called exophthalmia
+of progeny exhibited in so high a degree as it occurs in the parents as
+an immediate result of the operation, while, on examining any large
+stock of normal guinea-pigs, there is found a considerable amount of
+individual variation in regard to prominence of eyeballs. Therefore,
+while not denying that the obviously abnormal amount of protrusion due
+to the operation may be inherited in lesser degrees, and thus may be the
+cause of the unusual degree of prominence which is sometimes seen in the
+eyeballs of progeny born of exophthalmic parents, I am unable to affirm
+so important a conclusion on the basis supplied by these experiments.
+
+     6th. Haematoma and dry gangrene of the ears in animals born of
+     parents in which these ear-alterations had been caused by an injury
+     to the restiform body.
+
+As regards the animals operated upon (i. e. the parents), I find that
+the haematoma and dry gangrene may supervene either several weeks after
+the operation, or at any subsequent time up to many months. When it does
+supervene it usually affects the upper parts of both ears, and may then
+eat its way down until, in extreme cases, it has entirely consumed
+two-thirds of the tissue of both ears. As regards the progeny of animals
+thus affected, in some cases, but by no means in all, a similarly morbid
+state of the ears may arise apparently at any time in the life-history
+of the individual. But I have observed that in cases where two or more
+individuals _of the same litter_ develop this diseased condition, they
+usually do so at about the same time--even though this be many months
+after birth, and therefore after the animals are fully grown. But in
+progeny the morbid process never goes so far as in the parents which
+have been operated upon, and it almost always affects the _middle_
+thirds of the ears. In order to illustrate these points, reproductions
+of two of my photographs are appended. They represent the consequences
+of the operation on a male and a female guinea-pig. Among the progeny of
+both these animals there were several in which a portion of each ear was
+consumed by apparently the same process, where, of course, there had
+been no operation.
+
+[Illustration: FIG. 1.--Reproduction of photographs from life of a male
+and female guinea-pig, whose left restiform bodies had been injured by a
+scalpel six months previously. The loss of tissue in both ears was due
+to haematoma and dry gangrene, which, however, had ceased when the
+photograph was taken.]
+
+It should be observed that not only is a different _part_ of the ear
+affected in the progeny, but also a very much less _quantity_ thereof.
+Naturally, therefore, the hypothesis of heredity seems less probable
+than that of mere coincidence on the one hand, or of transmitted
+microbes on the other. But I hope to have fairly excluded both these
+alternative explanations. For, as regards merely accidental coincidence,
+I have never seen this very peculiar morbid process in the ears, or in
+any other parts, of guinea-pigs which have neither themselves had their
+restiform bodies injured, nor been born of parents thus mutilated. As
+regards the hypothesis of microbes, I have tried to inoculate the
+corresponding parts of the ears of normal guinea-pigs, by first
+scarifying those parts and then rubbing them with the diseased surfaces
+of the ears of mutilated guinea-pigs; but have not been able in this way
+to communicate the disease.
+
+It will be seen that the above results in large measure corroborate the
+statements of Brown-Sequard; and it is only fair to add that he told me
+they are the results which he had himself obtained most frequently, but
+that he had also met with many cases where the diseased condition of the
+ears in parents affected the same parts in their progeny, and also
+occurred in more equal degrees. Lastly, I should like to remark, with
+regard to these experiments on restiform bodies, and for the benefit of
+any one else who may hereafter repeat them, that it will be necessary
+for him to obtain precise information touching the _modus operandi_. For
+it is only one very localized spot in each restiform body which has to
+be injured in order to produce any of the results in question. I myself
+lost two years of work on account of not knowing this exact spot before
+going to Paris for the purpose of seeing Brown-Sequard himself perform
+the operation. I had in the preceding year seen one of his assistants do
+so, but this gentleman had a much more careless method, and one which in
+my hands yielded uniformly negative results. The exact spot in question
+in the restiform body is as far forwards as it is possible to reach, and
+as far down in depth as is compatible with not producing rotatory
+movements.
+
+     7th. Absence of two toes out of the three of the hind leg, and
+     sometimes of the three, in animals whose parents had eaten up their
+     hind-leg toes which had become anaesthetic from a section of the
+     sciatic nerve alone, or of that nerve and also of the crural.
+     Sometimes, instead of complete absence of the toes, only a part of
+     one or two or three was missing in the young, although in the
+     parent not only the toes but the whole foot were absent.
+
+As I found that the results here described were usually given by
+division of the sciatic nerve alone--or, more correctly, by excision of
+a considerable portion of the nerve, in order to prevent regeneration--I
+did not also divide the crural. But, although I have bred numerous
+litters from parents thus injured, there has been no case of any
+inherited deficiency of toes. My experiments in this connexion were
+carried on through a series of six successive generations, so as to
+produce, if possible, a cumulative effect. Nevertheless, no effect of
+any kind was produced. On the other hand, Brown-Sequard informed me that
+he had observed this inherited absence of toes only in about one or two
+per cent. of cases. Hence it is possible enough, that my experiments
+have not been sufficiently numerous to furnish a case. It may be added
+that there is here no measurable possibility of accidental coincidence
+(seeing that normal guinea-pigs do not seem ever to produce young with
+any deficiency of toes), while the only possibility of mal-observation
+consists in some error with regard to the isolation (or the tabulation)
+of parents and progeny. Such an error, however, may easily arise. For
+gangrene of the toes does not set in till some considerable time after
+division of the sciatic nerve. Hence, if the wound be healed before the
+gangrene begins, and if any mistake has been made with regard to the
+isolation (or tabulation) of the animal, it becomes possible that the
+latter should be recorded as an uninjured, instead of an injured,
+individual. On this account one would like to be assured that
+Brown-Sequard took the precaution of examining the state of the sciatic
+nerve in those comparatively few specimens which he alleges to have
+displayed such exceedingly definite proof of the inheritance of a
+mutilation. For it is needless to remark, after what has been said in
+the preceding chapter on the analogous case of epilepsy, that the proof
+would not be regarded by any physiologist as displaced by the fact that
+there is no observable deficiency in the sciatic nerve of the toeless
+young.
+
+     8th. Appearance of various morbid states of the skin and hair of
+     the neck and face in animals born of parents having had similar
+     alterations in the same parts, as effects of an injury to the
+     sciatic nerve.
+
+I have not paid any attention to this paragraph, because the facts which
+it alleges did not seem of a sufficiently definite character to serve as
+a guide to further experiment.
+
+On the whole, then, as regards Brown-Sequard's experiments, it will be
+seen that I have not been able to furnish any approach to a full
+corroboration. But I must repeat that my own experiments have not as yet
+been sufficiently numerous to justify me in repudiating those of his
+statements which I have not been able to verify.
+
+The only other experimental results, where animals are concerned, which
+seemed to tell on the side of Lamarckianism, are those of Mr.
+Cunningham, already alluded to. But, as the research is still in
+progress, the school of Weismann may fairly say that it would be
+premature to discuss its theoretical bearings.
+
+       *       *       *       *       *
+
+Passing now from experiments on animals to experiments on plants, I must
+again ask it to be borne in mind, that here also no researches have been
+published, which have had for their object the testing of the question
+on which we are engaged. As in the case of animals, therefore, so in
+that of plants, we are dependent for any experimental results bearing
+upon the subject to such as have been gained incidentally during the
+course of investigations in quite other directions.
+
+Allusion has already been made, in my previous essay, to De Vries'
+observations on the chromatophores of algae passing from the ovum of the
+mother to the daughter organism; and we have seen that even Weismann
+admits, "It appears possible that a transmission of somatogenetic
+variation has here occurred[71]." It will now be my object to show that
+such variations appear to be sometimes transmitted in the case of
+higher plants, and this under circumstances which carry much less
+equivocal evidence of the inheritance of acquired characters, than can
+be rendered by the much more simple organization of an alga.
+
+    [71] _Examination of Weismannism_, p. 83.
+
+I have previously mentioned Hoffmann's experiments on transplantation,
+the result of which was to show that variations, directly induced by
+changed conditions of life, were reproduced by seed[72]. Weismann,
+however, as we have seen, questions the _somatogenetic_ origin of these
+variations--attributing the facts to a _blastogenetic_ change produced
+in the plants by a direct action of the changed conditions upon the
+germ-plasm itself[73]. And he points out that whether he is right or
+wrong in this interpretation can only be settled by ascertaining whether
+the observable somatic changes occur in the generation which is first
+exposed to the changed conditions of life. If they do occur in the first
+generation, they are somatogenetic changes, which afterwards react on
+the substance of heredity, so as to transmit the acquired peculiarities
+to progeny. But if they do not occur till the second (or any later)
+generation, they are presumably blastogenetic. Unfortunately Hoffmann
+does not appear to have attended to this point with sufficient care, but
+there are other experiments of the same kind where the point has been
+specially observed.
+
+    [72] _Examination of Wiesmannism_, p. 93.
+
+    [73] _Ibid._ p. 153.
+
+For instance, M. L. A. Carriere[74] gathered seed from the wild radish
+(_Raphanus Raphanistrum_) in France, and sowed one lot in the light dry
+soil near the Museum of Natural History in Paris, while another lot was
+sown by him at the same time in heavy soil elsewhere. His object was to
+ascertain whether he could produce a good cultivated radish by
+methodical selection; and this he did; in a wonderfully rapid manner,
+during the course of a very few generations. But the point for us is,
+that _from the first_ the plants grown in the light soil of Paris
+presented sundry marked differences from those grown in the heavy soil
+of the country; and that these points of difference had nothing to do
+with the variations on which his artificial selection was brought to
+bear. For while his artificial selection was directed to increasing the
+_size_ of the "root," the differences in question had reference to its
+_form_ and _colour_. In Paris an elongated form prevailed, which
+presented either a white or a rose colour: in the country the form was
+more rounded, and the colour violet, dark brown, or "almost black." Now,
+as these differences were strongly apparent in the first generation, and
+were not afterwards made the subject of selection, both in origin and
+development they must have been due to "climatic" influences acting on
+the somatic tissues. And although the author does not appear to have
+tested their hereditary characters by afterwards sowing the seed from
+the Paris variety in the country, or _vice versa_, we may fairly
+conclude that these changes must have been hereditary--1st, from the
+fact of their intensification in the course of the five sequent
+generations over which the experiment extended, and, 2nd, from the very
+analogous results which were similarly obtained in the following case
+with another genus, where both the somatogenetic and the hereditary
+characters of the change were carefully and specially observed. This
+case is as follows.
+
+    [74] _Origine des Plantes Domestiques, demontree par la culture du
+         Radis Sauvage_ (Paris, 1869).
+
+The late Professor James Buckman, F.R.S., saved some seed from wild
+parsnips (_P. sativa_) in the summer of 1847, and sowed under changed
+conditions of life in the spring of 1848. The plants grown from these
+wild seeds were for the most part like wild plants; but some of them had
+"already (i.e. in the autumn of 1848) the light green and smooth aspect
+devoid of hairs which is peculiar to the cultivated plant; and among the
+latter there were a few with longer leaves and broader divisions of
+leaf-lobes than the rest--the leaves, too, all growing systematically
+round one central bud. The roots of the plant when taken up were
+observed to be for the most part more fleshy than those of wild
+examples[75]."
+
+    [75] _Journl. Agric. Soc._ 1848.
+
+Professor Buckman then proceeds to describe how he selected the best
+samples for cultivation in succeeding generations, till eventually the
+variety which he called "The Student" was produced, and which Messrs.
+Sutton still regard as the best variety in their catalogue. That is to
+say, it has come true to seed for the last forty years; and although
+such great excellence and stability are doubtless in chief part due to
+the subsequent process of selection by Professor Buckman in the years
+1848-1850, this does not affect the point with which we are here
+concerned--namely, that the somatogenetic changes of the plants in the
+first generation were transmitted by seed to the second generation, and
+thus furnished Professor Buckman with the material for his subsequent
+process of selection. And the changes in question were not merely of a
+very definite character, but also of what may be termed a very _local_
+character--affecting only particular tissues of the soma, and therefore
+expressive of a high degree of _representation_ on the part of the
+subsequently developed seed, by which they were faithfully reproduced in
+the next generation.
+
+Here is another case. M. Lesage examined the tissues of a large number
+of plants growing both near to, and remote from, the sea. He suspected
+that the characteristic fleshiness, &c. of seaside plants was due to the
+influence of sea-salt; and proved that such was the case by causing the
+characters to occur in inland plants as a result of watering them with
+salt-water. Then he adds:--
+
+     "J'ai reussi surtout pour le _Lepidium sativum_ cultive en 1888;
+     j'ai obtenu pour la meme plante des resultats plus nets encore dans
+     la culture de 1889, entreprise en semant les graines recoltees avec
+     soin des pots de l'annee precedente et traitees exactement de la
+     meme facon[76]."
+
+    [76] _Rev. Gen. de Bot._ tom. ii. p. 64.
+
+Here, it will be observed, there was no selection; and therefore the
+increased hereditary effect in the second generation must apparently be
+ascribed to a continuance of influence exercised by somatic tissues on
+germinal elements; for at the time when the changes were produced no
+seed had been formed. In other words, the accumulated change, like the
+initial change, would seem to have been exclusively of somatogenetic
+origin; and yet it so influenced the qualities of the seed (as this was
+afterwards formed), that the augmented changes were transmitted to the
+next generation, part for part, as the lesser changes had occurred in
+the preceding generation. "This experiment, therefore, like Professor
+Buckman's, shows that the alteration of the tissues was carried on in
+the second generation from the point gained in the first. In both cases
+no germ-plasm (in the germ-cells) existed at the time during which the
+alterations arose, as they were confined to the vegetative system; and
+in the case of the parsnips and carrots, being biennials no germ-cells
+are produced till the second year has arrived[77]."
+
+    [77] I am indebted to the Rev. G. Henslow for the references to
+         these cases. This and the passages which follow are quoted from
+         his letters to me.
+
+Once more, Professor Bailey remarks:--
+
+     "Squashes often show remarkable differences when grown upon
+     different soils; and these differences can sometimes be perpetuated
+     for a time by seeds. The writer has produced, from the same parent,
+     squashes so dissimilar, through the simple agency of a change of
+     soil in one season, that they might readily be taken for distinct
+     varieties. Peas are known to vary in the same manner. The seeds of
+     a row of peas of the same kind, last year gave the writer marked
+     variations due to differences of soil.... Pea-growers characterize
+     soils as 'good' and 'viney.' Upon the latter sort the plants run to
+     vine at the expense of the fruit, and their offspring for two or
+     three generations have the same tendency[78]."
+
+    [78] _Gardener's Chronicle_, May 31, 1890, p. 677.
+
+I think these several cases are enough to show that, while the
+Weismannian assumption as to the seeming transmission of somatogenetic
+characters being restricted to the lowest kinds of plants is purely
+gratuitous, there is no small amount of evidence to the contrary--or
+evidence which seems to prove that a similar transmission occurs
+likewise in the higher plants. And no doubt many additional cases might
+be advanced by any one who is well read in the literature of economic
+botany.
+
+It appears to me that the only answer to such cases would be furnished
+by supposing that the hereditary changes are due to an alteration of the
+residual "germ-plasm" in the wild seed, when this is first exposed to
+the changed conditions of life, due to its growth in a strange kind of
+soil--e.g. while germinating in an unusual kind of earth for producing
+the first generation. But this would be going a long way to save an
+hypothesis. In case, however, it should now be suggested, I may remark
+that it would be negatived by the following facts.[79]
+
+    [79] Since the above was written Professor Weismann has advanced, in
+         _The Germ-plasm_, a suggestion very similar to this. It is
+         sufficient here to remark, that nearly all the facts and
+         considerations which ensue in the present chapter are
+         applicable to his suggestion, the essence of which is
+         anticipated in the above paragraph.
+
+In the first place, an endless number of cases might be quoted where
+somatogenetic changes thus produced by changed conditions of life are
+not hereditary. Therefore, in all these cases it is certainly not the
+"germ-plasm" that is affected. In other words, there can be no question
+that somatogenetic changes of the kinds above mentioned do very readily
+admit of being produced in the first generation by changes of soil,
+altitude, &c. And that somatogenetic changes thus produced should not
+always--or even generally--prove themselves to be hereditary from the
+first moment of their occurrence, is no more than any theory of
+heredity would expect. Indeed, looking to the known potency of
+reversion, the wonder is that in any case such changes should become
+hereditary in a single generation. On the other hand, there is no reason
+to imagine that the hypothetical germ-plasm--howsoever _unstable_ we may
+suppose it to be--can admit of being directly affected by a change of
+soil in a single generation. For, on this view, it must presumably be
+chiefly affected during the short time that the seed is germinating; and
+during that time the changed conditions can scarcely be conceived as
+having any points of attack, so to speak, upon the residual germ-plasm.
+There are no roots on which the change of _soil_ can make itself
+perceptible, nor any stem and leaves on which the change of _atmosphere_
+can operate. Yet the changed condition's may produce hereditary
+modifications in any parts of the plant, which are not only precisely
+analogous to non-hereditary changes similarly produced in the somatic
+tissues of innumerable other plants, but are always of precisely the
+same kind in the same lot of plants that are affected. When all the
+radishes grown from wild seed in Paris, for instance, varied in the
+direction of rotundity and dark colour, while those grown in the country
+presented the opposite characters, we can well understand the facts as
+due to an entire season's action upon the whole of the growing plant,
+with the result that all the changes produced in each set of plants were
+similar--just as in the cases where similarly "climatic" modifications
+are not hereditary, and therefore unquestionably due to changed
+conditions acting on roots, stems, leaves, or flowers, as the case may
+be. On the other hand, it is not thus intelligible that during the
+short time of germination the changed conditions should effect a
+re-shuffling (or any other modification) of the "germ-plasm" in the
+seeds--and this in such a manner that the effect on the residual
+germ-plasm reserved for future generations is precisely similar to that
+produced on the somatic tissues of the developing embryo.
+
+In the second place, as we have seen, in some of the foregoing cases the
+changes were produced months--and even years--before the seeds of the
+first germination were formed. Therefore the hereditary effect, if
+subsequent to the period of embryonic germination, must have been
+produced on germ-plasm as this occurs diffused through the somatic
+tissues. But, if so, we shall have to suppose that such germ-plasm is
+afterwards gathered in the seeds when these are subsequently formed.
+This supposition, however, would be radically opposed to Weismann's
+theory of heredity: nor do I know of any other theory with which it
+would be reconcilable, save such as entertain the possibility of the
+Lamarckian factors.
+
+Lastly, in the third place, I deem the following considerations of the
+highest importance:--
+
+     "As other instances in which peculiar structures are now hereditary
+     may be mentioned aquatic plants and those producing subterraneous
+     stems. Whether they be dicotyledons or monocotyledons, there is a
+     fundamental agreement in the anatomy of the roots and stem of
+     aquatic plants, and, in many cases, of the leaves as well. Such has
+     hitherto been attributed to the aquatic habit. The inference or
+     deduction was, of course, based upon innumerable coincidences; the
+     water being supposed to be the direct cause of the degenerate
+     structures, which are hereditary and characteristic of such plants
+     in the wild state. M. Costantin has, however, verified this
+     deduction, by making terrestrial and aerial stems to grow
+     underground and in water: the structures _at once_ began to assume
+     the subterranean or aquatic type, as the case might be; and,
+     conversely, aquatic plants made to grow upon land _at once_ began
+     to assume the terrestrial type of structure, while analogous
+     results followed changes from a subterranean to an aerial position,
+     and _vice versa_."
+
+This is also quoted from the Rev. Prof. Henslow's letters to me, and the
+important point in it is, that the great changes in question are proved
+to be of a purely "somatogenetic" kind; for they occurred "at once" _in
+the ready-grown plant_, when the organs concerned were exposed to the
+change from aquatic to terrestrial life, or _vice versa_--and also from
+a subterranean to an aerial position, or _vice versa_. Consequently,
+even the abstract possibility of the changed conditions of life having
+operated on the _seed_ is here excluded. Yet the changes are of
+precisely the same kind as are now _hereditary_ in the wild species. It
+thus appears undeniable that all these remarkable and uniform changes
+must originally have been somatogenetic changes; yet they have now
+become blastogenetic. This much, I say, seems undeniable; and therefore
+it goes a long way to prove that the non-blastogenetic character of the
+changes has been due to their originally somatogenetic character. For,
+if not, how did natural selection ever get an opportunity of making any
+of them blastogenetic, when every individual plant has always presented
+them as already given somatogenetically? This last consideration appears
+in no small measure to justify the opinion of Mr. Henslow, who
+concludes--"These experiments prove, not only that the influence of the
+environment is _at once_ felt by the organ; but that it is indubitably
+the _cause_ of the now specific and hereditary traits peculiar to
+normally aquatic, subterranean, and aerial stems, or roots[80]."
+
+    [80] It also serves to show that Weismann's newer doctrine of
+         similar "determinants" occurring both in the germ and in the
+         somatic tissues is a doctrine which cannot be applied to rebut
+         this evidence of the transmission of acquired characters in
+         plants. Therefore even its hypothetical validity as applied by
+         him to explain the seasonal variation of butterflies is
+         rendered in a high degree dubious.
+
+He continues to furnish other instances in the same line of proof--such
+as the distinctive "habits" of insectivorous, parasitic, and climbing
+plants; the difference in structure between the upper and under sides of
+horizontal leaves, &c. "For here, as in all organs, we discover by
+experiment how easily the anatomy of plants can be affected by their
+environment; and that, as long as the latter is constant, so are the
+characters of the plants constant and hereditary."
+
+     [The following letter, contributed by Dr. Hill to _Nature_, vol. I.
+     p. 617, may here be quoted. C. Ll. M.
+
+     "It may be of interest to your readers to know that two guinea-pigs
+     were born at Oxford a day or two before the death Dr. Romanes, both
+     of which exhibited a well-marked droop of the left upper eyelid.
+     These guinea-pigs were the offspring of a male and a female
+     guinea-pig in both of which I had produced for Dr. Romanes, some
+     months earlier, a droop of the left upper eyelid by division of the
+     left cervical sympathetic nerve. This result is a corroboration of
+     the series of Brown-Sequard's experiments on the inheritance of
+     acquired characteristics. A very large series of such experiments
+     are of course needed to eliminate all sources of error, but this I
+     unfortunately cannot carry out at present, owing to the need of a
+     special farm in the country, for the proper care and breeding of
+     the animals.--LEONARD HILL.
+
+     "Physiological Laboratory, Univ. Coll. London, Oct. 18, 1894."]
+
+
+
+
+CHAPTER V.
+
+CHARACTERS AS HEREDITARY AND ACQUIRED
+(_continued_).
+
+
+(A. and B.)
+
+
+_Direct and Indirect Evidence in favour of the Non-inheritance of
+Acquired Characters_[81].
+
+    [81] [_See_ note appended to Preface. C. LI. M.]
+
+The strongest argument in favour of "continuity" is that based upon the
+immense difference between congenital and acquired characters in respect
+of heritability. For that there is a great difference in this respect is
+a matter of undeniable fact. And it is obvious that this difference, the
+importance of which must be allowed its full weight, is just what we
+should expect on the theory of the continuity of the germ-plasm, as
+opposed to that of pangenesis. Indeed it may be said that the difference
+in question, while it constitutes important _evidence_ in favour of the
+former theory, is a _difficulty_ in the way of the latter. But here two
+or three considerations must be borne in mind.
+
+In the first place, this fact has long been one which has met with wide
+recognition and now constitutes the main ground on which the theory of
+continuity stands. That is to say, it was the previous knowledge of
+this contrast between congenital and acquired characters which led to
+the formulation of a theory of continuity by Mr. Galton, and to its
+subsequent development by Prof Weismann.
+
+But, in the second place, there is a wide difference between the
+certainty of this fact and that of the theory based upon it. The certain
+fact is, that a great distinction in respect of heritability is
+observable between congenital and acquired characters. The theory, as
+formulated by Weismann, is that the distinction is not only great but
+absolute, or, in other words, that in no case and in no degree can any
+acquired character be ever inherited. This hypothesis, it will be
+observed, goes far beyond the observed fact, for it is obviously
+possible that, notwithstanding this great difference in regard to
+heritability between congenital and acquired characters, the latter may
+nevertheless, sometimes and in some degree, be inherited, however much
+difficulty we may experience in observing these lesser phenomena in
+presence of the greater. The Weismannian hypothesis of _absolute_
+continuity is one thing, while the observed fact of at least a _high
+relative degree_ of continuity is quite another thing. And it is
+necessary to be emphatic on this point, since some of the reviewers of
+my _Examination of Weismannism_ confound these two things. Being
+apparently under the impression that it was reserved for Weismann to
+perceive the fact of there being a great difference between the
+heritability of congenital and acquired characters, they deem it
+inconsistent in me to acknowledge this fact while at the same time
+questioning the hypothetical basis of his fundamental postulate touching
+the absolute continuity of germ-plasm. It is one merit of Galton's
+theory, as against Weismann's, that it does not dogmatically exclude the
+possible interruption of continuity on some occasions and in some
+degree. Herein, indeed, would seem to lie the central core of the whole
+question in dispute. For it is certain and has long been known that
+individually acquired characters are at all events much less heritable
+than are long-inherited or congenital ones. But Lamarckian theory
+supposes that congenital characters were in some cases originally
+acquired, and that what are now blastogenetic characters were in some
+cases at first somatogenetic and have become blastogenetic only in
+virtue of sufficiently long inheritance. Since Darwin's time, however,
+evolutionists (even of the so-called Lamarckian type) have supposed that
+natural selection greatly assists this process of determining which
+somatogenetic characters shall become congenital or blastogenetic. Hence
+all schools of evolutionists are, and have long been, agreed in
+regarding the continuity principle as true in the main. No evolutionist
+would at any time have propounded the view that one generation depends
+for _all_ its characters on those acquired by its _immediate_ ancestors,
+for this would merely be to unsay the theory of Evolution itself, as
+well as to deny the patent facts of heredity as shown, for example, in
+atavism. At most only some fraction of a _per cent._ could be supposed
+to do so. But Weismann's contention is that this principle is not only
+true in the main, but _absolutely_ true; so that natural selection
+becomes all in all or not at all. Unless Weismannism be regarded as
+this doctrine of absolutism it permits no basis for his attempted theory
+of evolution.
+
+And, whatever may be said to the contrary by the more enthusiastic
+followers of Prof. Weismann, I must insist that there is the widest
+possible difference between the truly scientific question of fact which
+is assumed by Weismann as answered (the base-line of the diagram on p.
+43), and the elaborate structure of deductive reasoning which he has
+reared on this assumption (the Y-like structure). Even if the assumption
+should ever admit of inductive proof, the almost bewildering edifice of
+deductive reasoning which he has built upon it would still appear to me
+to present extremely little value of a scientific kind. Interesting
+though it may be as a monument of ingenious speculation hitherto unique
+in the history of science, the mere flimsiness of its material must
+always prevent its far-reaching conclusions from being worthy of serious
+attention from a biological point of view. But having already attempted
+to show fully in my _Examination_ this great distinction between the
+scientific importance of the question which lies at the base of
+"Weismannism," and that of the system which he has constructed on his
+assumed answer thereto, I need not now say anything further with regard
+to it.
+
+Again, on the present occasion and in this connexion I should like to
+dissipate a misunderstanding into which some of the reviewers of the
+work just mentioned have fallen. They appear to have concluded that
+because I have criticized unfavourably a considerable number of
+Weismann's theories, I have shown myself hostile to his entire system.
+Such, however, is by no means the case; and the misunderstanding can
+only be accounted for by supposing that the strongly partisan spirit
+which these critics display on the side of neo-Darwinism has rendered
+them incapable of appreciating any attempt at impartial--or even so much
+as independent--criticism. At all events, it is a matter of fact that
+throughout the work in question I have been particularly careful to
+avoid this misunderstanding as to my own position. Over and over again
+it is there stated that, far from having any objection to the principle
+of "Continuity" as represented in the base-line of the above diagram, I
+have been convinced of its truth ever since reading Mr. Galton's _Theory
+of Heredity_ in 1875. All the "hard words" which I have written against
+Weismann's system of theories have reference to those parts of it which
+go to constitute the Y-like structure of the diagram.
+
+It is, however, desirable to recur to another point, and one which I
+hope will be borne in mind throughout the following discussion. It has
+already been stated, a few pages back, that the doctrine of continuity
+admits of being held in two very different significations. It may be
+held as absolute, or as relative. In the former case we have the
+Weismannian doctrine of germ-plasm: the substance of heredity is taken
+to be a substance _per se_, which has always occupied a separate
+"sphere" of its own, without any contact with that of somatoplasm
+further than is required for its lodgement and nutrition; hence it can
+never have been in any degree modified as to its hereditary qualities by
+use-inheritance or any other kind of somatogenetic change; it has been
+_absolutely_ continuous "since the first origin of life." On the other
+hand, the doctrine of continuity may be held in the widely different
+sense in which it has been presented by Galton's theory of Stirp. Here
+the doctrine is, that while for the most part the phenomena of heredity
+are due to the continuity of the substance of heredity through
+numberless generations, this substance ("Stirp") is nevertheless not
+absolutely continuous, but may admit, in small though cumulative
+degrees, of modification by use-inheritance and other factors of the
+Lamarckian kind. Now this all-important distinction between these two
+theories of continuity has been fully explained and thoroughly discussed
+in my _Examination_; therefore I will not here repeat myself further
+than to make the following remarks.
+
+The Weismannian doctrine of continuity as absolute (base-line of the
+diagram) is necessary for the vast edifice of theories which he has
+raised upon it (the Y), first as to the minute nature and exact
+composition of the substance of heredity itself ("Germ-plasm"), next as
+to the precise mechanism of its action in producing the visible
+phenomena of heredity, variation, and all allied phenomena, and, lastly,
+the elaborate and ever-changing theory of organic evolution which is
+either founded on or interwoven with this vast system of hypothetic
+speculation. Galton's doctrine of continuity, on the other hand, is a
+"Theory of Heredity," and a theory of heredity alone. It does not meddle
+with any other matters whatsoever, and rigidly avoids all speculation
+further than is necessary for the bare statement and inductive support
+of the doctrine in question. Hence, it would appear that this, the only
+important respect wherein the doctrine of continuity as held by Galton
+differs from the doctrine as held by Weismann, arisen from the necessity
+under which the latter finds himself of postulating _absolute_
+continuity as a logical basis for his deductive theory of the precise
+mechanism of heredity on the one hand, and of his similarly deductive
+theory of evolution on the other. So far as the doctrine of continuity
+is itself concerned (i.e. the question of the inheritance of acquired
+characters), there is certainly no more inductive reason for supposing
+the continuity absolute "since the first origin of life," than there is
+for supposing it to be more or less susceptible of interruption by the
+Lamarckian factors. In other words, but for the sake of constructing a
+speculative foundation for the support of his further theories as to
+"the architecture of germ-plasm" and the factors of organic evolution,
+there is no reason why Weismann should maintain the absolute separation
+of the "sphere" of germ-plasm from that of somatoplasm. On the contrary,
+he has no reason for concluding against even a considerable and a
+frequent amount of cutting, or overlapping, on the part of these two
+spheres.
+
+But although this seems to me sufficiently obvious, as I have shown at
+greater length in the _Examination of Weismannism_, it must not be
+understood that I hold that there is room for any large amount of such
+overlapping. On the contrary, it appears to me as certain as anything
+can well be that the amount of such overlapping from one generation to
+another, if it ever occur at all, must be exceedingly small, so that,
+if we have regard to only a few sequent generations, the effects of
+use-inheritance, and Lamarckian factors are, at all events as a rule,
+demonstrably imperceptible. But this fact does not constitute any
+evidence--as Weismann and his followers seem to suppose--against a
+possibly important influence being exercised by the Lamarckian factors,
+in the way of gradual increments through a long series of generations.
+It has long been well known that acquired characters are at best far
+less fully and far less certainly inherited than are congenital ones.
+And this fact is of itself sufficient to prove the doctrine of
+continuity to the extent that even the Lamarckian is rationally bound to
+concede. But the fact yields no proof--scarcely indeed so much as a
+presumption--in favour of the doctrine of continuity as absolute. For it
+is sufficiently obvious that the adaptive work of heredity could not be
+carried on at all if there had to be a discontinuity in the substance of
+heredity at every generation, or even after any very large number of
+generations.
+
+Little more need be said concerning the arguments which fall under the
+headings A and B. The Indirect evidence is considered in Appendix I of
+the _Examination of Weismannism_; while the Direct evidence is
+considered in the text of that work in treating of Professor Weismann's
+researches on the _Hydromedusae_ (pp. 71-76).
+
+The facts of karyokinesis are generally claimed by the school of
+Weismann as making exclusively in favour of continuity as absolute. But
+this is a partisan view to take. In any impartial survey it should be
+seen that while the facts are fairly interpretable on Weismann's theory,
+they are by no means proof thereof. For any other theory of Heredity
+must suppose the material of heredity to be of a kind more or less
+specialized, and the mechanism of heredity extremely precise and well
+ordered. And this is all that the facts of karyokinesis prove. Granting
+that they prove continuity, they cannot be held to prove that continuity
+to be absolute. In other words, the facts are by no means incompatible
+with even a large amount of commerce between germ-plasm and
+somato-plasm, or a frequent transmission of acquired characters.
+
+Again, Weismann's theory, that the somatic and the germ-plasm
+determinants may be similarly and simultaneously modified by external
+conditions may be extended much further than he has used it himself, so
+as to exclude, or at any rate invalidate, _all_ evidence in favour of
+Lamarckianism, other than the inheritance of the effects of use and
+disuse. All evidence from apparently inherited effects produced by
+change of external conditions is thus virtually put out of court,
+leaving only evidence from the apparently inherited effects of
+functionally produced modifications. And this line of evidence is
+invalidated by Panmixia. Hence there remain only the arguments from
+selective value and co-adaptation. Weismann meets these by adducing the
+case of neuter insects, which have been already considered at sufficient
+length.
+
+
+(C.)
+_Experimental Evidence as to the Non-inheritance of Acquired
+Characters._
+
+
+Let us now proceed to the experimental evidence which has been adduced
+on the side of Weismannism.
+
+Taking this evidence in order of date, we have first to mention that on
+which the school of Weismann has hitherto been satisfied almost
+exclusively to rely. This is the line of negative evidence, or the
+seeming absence of any experimental demonstration of the inheritance of
+acquired characters. This kind of evidence, however, presents much less
+cogency than is usually supposed. And it has been shown in the last
+chapter that the amount of experimental evidence in favour of the
+transmission of acquired characters is more considerable than the school
+of Weismann seems to be aware--especially in the vegetable kingdom. I do
+not think that this negative line of evidence presents much weight; and,
+to show that I am not biassed in forming this judgement, I may here
+state that few have more reason than myself for appreciating the weight
+of such evidence. For, as already stated, when first led to doubt the
+Lamarckian factors, now more than twenty years ago, I undertook a
+research upon the whole question--only a part of which was devoted to
+testing the particular case of Brown-Sequard's statements, with the
+result recorded in the preceding chapter. As this research yielded
+negative results in all its divisions--and, not only in the matter of
+Brown-Sequard's statements--I have not hitherto published a word upon
+the subject. But it now seems worth while to do so, and for the
+following reasons.
+
+First, as just observed, a brief account of my old experiences in this
+field will serve to show what good reason I have for feeling the weight
+of such negative evidence in favour of Continuity as arises from failure
+to produce any good experimental evidence to the contrary. In the second
+place, now that the question has become one of world-wide interest, it
+would seem that even negative results deserve to be published for
+whatever they may be worth on the side of Neo-Darwinism. Lastly, in the
+third place, although the research yielded negative results in my hands,
+it is perhaps not undesirable to state the nature of it, if only to
+furnish suggestions to other physiologists, in whose hands the
+experiments--especially in these days of antiseptics--may lead to a
+different termination. Altogether I made thousands of experiments in
+graft-hydridization (comprising bines, bulbs of various kinds, buds, and
+tubers); but with uniformly negative results. With animals I tried a
+number of experiments in grafting characteristic congenital tissues from
+one variety on another--such as the combs of Spanish cocks upon the
+heads of Hamburgs; also, in mice and rats, the grafting together of
+different varieties; and, in rabbits and bitches, the transplantation of
+ovaries of newly-born individuals belonging to different well-marked
+breeds. This latter experiment seems to be one which, if successfully
+performed (so that the transplanted ovaries would form their attachment
+in a young bitch puppy and subsequently yield progeny to a dog of the
+same breed as herself) would furnish a crucial test as to the
+inheritance or non-inheritance of acquired characters. Therefore I
+devoted to it a large share of my attention, and tried the experiment in
+several different ways. But I was never able to get the foreign
+ovary--or even any portion thereof--to graft. Eventually the passing of
+the Vivisection Act caused me to abandon the whole research as far as
+animals were concerned--a research, indeed, of which I had become
+heartily tired, since in no one instance did I obtain any adhesion.
+During the last few years, however, I have returned to these experiments
+under a licence, and with antiseptic precautions, but with a similar
+want of success. Perhaps this prolonged and uniformly fruitless
+experience may now have the effect of saving the time of other
+physiologists, by warning them off the roads where there seems to be no
+thoroughfare. On the other hand, it may possibly lead some one else to
+try some variation in the method, or in the material, which has not
+occurred to me. In particular, I am not without hope that the
+transplantation of ovaries in very young animals may eventually prove to
+be physiologically possible; and, if so, that the whole issue as between
+the rival theories of heredity will be settled by the result of a single
+experiment. Possibly some of the invertebrata will be found to furnish
+the suitable material, although I have been unable to think of any of
+these which present sufficiently well-marked varieties for the purpose.
+But, pending the successful accomplishment of this particular experiment
+in the grafting of any animal tissue, I think it would be clearly
+unjustifiable to conclude against the Lamarckian factors on the ground
+of any other experiments yielding negative results in but one generation
+or even in a large number of sequent generations.
+
+For instance, the latter consideration applies to the negative results
+of Mr. Francis Galton's celebrated _Experiments in Pangenesis_.[82].
+These consisted in transfusing the blood of one variety of rabbit into
+the veins of both sexes of another, and then allowing the latter to
+breed together: in no case was there any appearance in the progeny of
+characters distinctive of the variety from which the transfused blood
+was derived. But, as Mr. Galton himself subsequently allowed, this
+negative result constitutes no disproof of pangenesis, seeing that only
+a portion of the parents' blood was replaced; that this portion, even if
+charged with "gemmules," would contain but a very small number of these
+hypothetical bodies, compared with those contained in all the tissues of
+the parents; and that even this small proportional number would
+presumably be soon overwhelmed by those contained in blood newly-made by
+the parents. Nevertheless the experiment was unquestionably worth
+trying, on the chance of its yielding a positive result; for, in this
+event, the question at issue would have been closed. Accordingly I
+repeated these experiments (with the kind help of Professor Schaefer),
+but with slight differences in the method, designed to give pangenesis a
+better chance, so to speak.
+
+    [82] _Proc. R. S. 1871._
+
+Thus I chose wild rabbits to supply the blood, and Himalayan to receive
+it--the former being the ancestral type (and therefore giving reversion
+an opportunity of coming into play), while the latter, although a
+product of domestication, is a remarkably constant variety, and one
+which differs very much in size and colour from the parent species.
+Again, instead of a single transfusion, there were several transfusions
+performed at different times. Moreover, we did not merely allow the
+blood of one rabbit to flow into the veins of the other (whereby little
+more than half the blood could be substituted); but sacrificed three
+wild rabbits for refilling the vascular system of each tame one on each
+occasion. Even as thus improved, however, the experiment yielded only
+negative results, which, therefore, we never published.
+
+Subsequently I found that all this labour, both on Mr. Galton's part and
+our own, was simply thrown away--not because it yielded only negative
+results, but because it did not serve as a crucial experiment at all.
+The material chosen was unserviceable for the purpose, inasmuch as
+rabbits, even when crossed in the ordinary way, never throw intermediate
+characters. Needless to say, had I been aware of this fact before, I
+should never have repeated Mr. Galton's experiments--nor, indeed, would
+he have originally performed them had he been aware of it. So all this
+work goes for nothing. The research must begin all over again with some
+other animals, the varieties of which when crossed do throw intermediate
+characters.
+
+Therefore I have this year made arrangements for again repeating the
+experiments in question--only, instead of rabbits, using well-marked
+varieties of dogs. A renewed attack of illness, however, has
+necessitated the surrender of this research to other hands, with a
+consequent delay in its commencement.
+
+My ignorance of the unfortunate peculiarity displayed by rabbits in not
+throwing intermediate characters has led to a further waste of time in
+another line of experiment. On finding that mammalian ovaries did not
+admit of being grafted, it seemed to me that the next best thing to try
+would be the transplantation of fertilized ova from one variety to
+another, for the purpose of ascertaining whether, if a parturition
+should take place under such circumstances, gestation by the uterine
+mother would affect the characters of the ovum derived from the ovarian
+mother--she, of course, having been fertilized by a male of her own
+variety. Of course it was necessary that both the mothers should be in
+season at about the same time, and therefore I again chose rabbits,
+seeing that in the breeding season they are virtually in a chronic state
+of "heat." I selected Himalayans and Belgian hares, because they are
+well-marked varieties, breed true, and in respect of colour are very
+different from one another. It so happened that while I was at work upon
+this experiment, it was also being tried, unknown to me, by Messrs.
+Heape and Buckley who, curiously enough, employed exactly the same
+material. They were the first to obtain a successful result. Two
+fertilized ova of the Angora breed having been introduced into the
+fallopian tube of a Belgian hare, developed there in due course, and
+gave rise to two Angora rabbits in no way modified by their Belgian hare
+gestation[83].
+
+    [83] _Proc. R. S. 1890_, vol. xlviii. p. 457. It should be stated
+         that the authors do not here concern themselves with any theory
+         of heredity.
+
+But, interesting and suggestive as this experiment is in other
+connexions, it is clearly without significance in the present one, for
+the reason already stated. It will have to be tried on well-marked
+varieties of other species of animals, which are known to throw
+intermediate characters. Even, however, if it should then yield a
+similarly negative result, the fact would not tell against the
+inheritance of acquired characters; seeing that an ovum by the time it
+is ripe is a finished product, and therefore not to be expected, on any
+theory of heredity, to be influenced as to its hereditary potentialities
+by the mere process of gestation. On the other hand, if it should prove
+that it does admit of being thus affected, so that against all
+reasonable expectation the young animal presents any of the hereditary
+characters of its uterine mother, the fact would terminate the question
+of the transmission of acquired characters--and this quite as
+effectually as would a similarly positive result in the case of progeny
+from an ingrafted ovary of a different variety. In point of fact, the
+only difference between the two cases would be, that in the former it
+_might_ prove possible to close the question on the side of
+Lamarckianism, in the latter it would _certainly_ close the question,
+either on this side or on the opposite as the event would determine.
+
+The only additional fact that has hitherto been published by the school
+of Weismann is the result of Weismann's own experiment in cutting off
+the tails of mice through successive generations. But this experiment
+does not bear upon any question that is in debate; for no one who is
+acquainted with the literature of the subject would have expected any
+positive result to follow from such a line of inquiry. As shown further
+back in the text, Darwin had carefully considered the case of
+mutilations, and explained that their non-transmissibility constitutes
+no valid objection to his theory of pangenesis. Furthermore, it may now
+be added, he expressly alluded in this connexion to the cutting off of
+tails, as practised by horse-breeders and dog-fanciers, "through a
+number of generations, without any inherited effect." He also alluded to
+the still better evidence which is furnished by the practice of
+circumcision. Therefore it is difficult to understand the object of
+Weismann's experiment. Yet, other than the result of this experiment, no
+new fact bearing on the question at issue has been even so much as
+alleged.
+
+
+
+
+CHAPTER VI.
+
+CHARACTERS AS HEREDITARY AND ACQUIRED
+(_conclusion_[84]).
+
+    [84] _See_ note appended to Preface. C. Ll. M.
+
+In the foregoing chapters I have endeavoured to be, before all things,
+impartial; and if it seems that I have been arguing chiefly in favour of
+the Lamarckian principles, this has been because the only way of
+examining the question is to consider what has to be said on the
+affirmative side, and then to see what the negative side can say in
+reply. Before we are entitled to discard the Lamarckian factors _in
+toto_, we must be able to destroy all evidence of their action. This,
+indeed, is what the ultra-Darwinians profess to have done. But is not
+their profession premature? Is it not evident that they have not
+sufficiently considered certain general facts of nature, or certain
+particular results of experiment, which at all events appear
+inexplicable by the theory of natural selection alone? In any case the
+present discussion has been devoted mainly to indicating such general
+facts and particular results. If I have fallen into errors, either of
+statement or of reasoning, it is for the ultra-Darwinians to correct
+them; but it may be well to remark beforehand, that any criticism of a
+merely general kind touching the comparative paucity of the facts thus
+adduced in favour of Lamarckian doctrine, will not stand as a valid
+criticism. For, as we have seen in the opening part of the discussion,
+even if use-inheritance and direct action of the environment have been
+of high importance as factors of organic evolution, it must be in almost
+all cases impossible to dissociate their influence from that of natural
+selection--at any rate where plants and animals in a state of nature are
+concerned. On the other hand, experiments expressly devised to test the
+question have not hitherto been carried out. Besides, the facts and
+arguments here adduced are but _comparatively_ few. For, unless it can
+be shown that what has been said of reflex action, instinct, so-called
+"self-adaptation" in plants, &c., is wrong in principle, the facts which
+tell in favour of Lamarckian theory are _absolutely_ very numerous. Only
+when considered in relation to cases where we are unable to exclude the
+conceivable possibility of natural selection having been at work, can it
+be said that the facts in question are not numerous.
+
+Comparatively few, then, though the facts may be of which I have given
+some examples, in my opinion they are amply sufficient for the purpose
+in hand. This purpose is to show that the question which we are now
+considering is very far from being a closed question; and, therefore,
+that the school of Weismann is much too precipitate in alleging that
+there is neither any necessity for, nor evidence of, the so-called
+Lamarckian factors[85]. And this opinion, whatever it may be worth, is
+at all events both deliberate and impartial. As one of the first to
+doubt the transmission of acquired characters, and as one who has spent
+many years in experimental inquiries upon the subject, any bias that I
+may have is assuredly against the Lamarckian principles--seeing that
+nearly all my experiments have yielded negative results. It was Darwin
+himself who checked this bias. But if the ultra-Darwinians of the last
+ten years had succeeded in showing that Darwin was mistaken, I should be
+extremely glad to fall into line with them. As already shown, however,
+they have in no way affected this question as it was left by Galton in
+1875. And if it be supposed a matter of but little importance whether we
+agree with Galton in largely diminishing the comparative potency of the
+Lamarckian principles, or whether we agree with Weismann in abolishing
+them together, it cannot be too often repeated that such is an entirely
+erroneous view. No matter how faintly or how fitfully acquired
+characters may be transmitted, in so far as they are likewise adaptive
+characters, their transmission (and therefore their development) must be
+cumulative. Hence, the only effect of attenuating our estimate of their
+_intensity_, is that of increasing our estimate of their
+_duration_--i.e. of the time over which they have to operate in order to
+produce important results. And, even so, it is to be remembered that
+the importance of such results is not to be estimated by the magnitude
+of modification. Far more is it to be estimated by the character of
+modification as adaptive. For if functionally produced changes, and
+changes produced in adaptive response to the environment, are ever
+transmitted in a cumulative manner, a time must sooner or later arrive
+when they will reach a selective value in the struggle for
+existence--when, of course, they will be rapidly augmented by natural
+selection. Thus, if in any degree operative at all, the great function
+of these principles must be that of supplying to natural selection those
+incipient stages of adaptive modifications in all cases where, but for
+their agency, there would have been nothing of the kind to select.
+Themselves in no way dependent on adaptive modifications having already
+attained a selective value, these Lamarckian principles are (under the
+Darwinian theory) direct causes of determinate variation in adaptive
+lines; and variation in those lines being cumulative, the result is that
+natural selection is in large part presented with the raw material of
+its manufacture--special material of the particular kinds required, as
+distinguished from promiscuous material of all kinds. And the more
+complex the manufacture the more important will be the work of this
+subordinate factory. We can well imagine how the shell of a nut, for
+instance, or even the protective colouring of an insect, may have been
+gradually built up by natural selection alone. But just in proportion as
+structures or organs are not merely thus of passive _use_ (where, of
+course, the Lamarckian principles cannot obtain), but require to be
+actively _used_, in that proportion does it become difficult to
+understand the _incipient_ construction of them by natural selection
+alone. Therefore, in many such cases, if the incipient construction is
+not to be explained by the Lamarckian principles, it is difficult to see
+how it is to be explained at all.
+
+    [85] E.g. "The supposed transmission of this artificially produced
+         disease (epilepsy) is the only definite instance which has been
+         brought forward in support of the transmission of acquired
+         characters."--_Essays_, p. 328.
+
+Furthermore, since the question as to the transmission of acquired
+characters stands now exactly as it did after the publication of Mr.
+Galton's _Theory of Heredity_ twenty years ago, it would seem that our
+judgement with regard to it should remain exactly what it was then.
+Although we must "out-Darwin Darwin" to the extent of holding that he
+assigned too large a measure of intensity to the Lamarckian factors, no
+sufficient reason has been shown for denying the existence of these
+factors _in toto_; while, on the other hand, there are certain general
+considerations, and certain particular facts, which appear to render it
+probable that they have played a highly important part in the process of
+organic evolution as a whole. At the same time, and in the present state
+of our information, this judgement must be deemed provisional, or liable
+eventually to be overturned by experimental proof of the non-inheritance
+of acquired characters. But, even if this should ever be finally
+accomplished, the question would still remain whether the principle of
+natural selection alone is capable of explaining all the facts of
+adaptation; and, for my own part, I should then be disposed to believe
+that there must be some other, though hitherto undiscovered, principle
+at work, which co-operates with natural selection, by playing the
+subordinate role which was assigned by Darwin to the principles of
+Lamarck.
+
+Finally, let it be noted that no part of the foregoing argument is to be
+regarded as directed against the _principle_ of what Professor Weismann
+calls "continuity." On the contrary, it appears to be self-evident that
+this principle must be accepted in some degree or another by every one,
+whether Darwinians, Neo-Darwinians, Lamarckians, Neo-Lamarckians, or
+even the advocates of special creation. Yet, to hear or to read some of
+the followers of Weismann, one can only conclude that, prior to his
+publications on the subject, they had never thought about it at all.
+These naturalists appear to suppose that until then the belief of
+Darwinians was, that there could be no hereditary "continuity" between
+any one organic type and another (such, for instance, as between Ape and
+Man), but that the whole structure of any given generation must be due
+to "gemmules" or "somato-plasm," derived exclusively from the preceding
+generation. Nothing can show more ignorance, or more thoughtlessness,
+with regard to the whole subject. The very basis of the general theory
+of evolution is that there must always have been a continuity in the
+material substance of heredity since the time when the process of
+evolution began; and it was not reserved for our generation, or even for
+our century, to perceive the special nature of this material substance
+in the case of sexual organisms. No, the real and the sole question,
+where Weismann's theory of heredity is concerned, is simply this--Are we
+to hold that this material substance has been _absolutely_ continuous
+"since the first origin of sexual propagation," always occupying a
+separate "sphere" of its own, at all events to the extent of never
+having been modified by the body substance in which it resides
+(Lamarckian factors); _or_, are we to hold that this "germ-plasm,"
+"stirp," or "formative-material," has been but _relatively_ continuous,
+so as to admit of some amount of commerce with body-substance, and
+therefore to admit of acquired characters, when sufficiently long
+continued as such, eventually becoming congenital? If this question be
+answered in the latter sense, of course the further question arises as
+to the _degree_ of such commerce, or the _time_ during which acquired
+characters must continue to be acquired in successive generations before
+they can sufficiently impress themselves on the substance of heredity to
+become congenital. But this is a subordinate question, and one which, in
+the present state of our information, it seems to me almost useless to
+speculate upon. My own opinion has always been the same as that of Mr.
+Galton; and my belief is that eventually both Weismann and his followers
+will gravitate into it. It was in order to precipitate this result as
+far as possible that I wrote the _Examination_. If it ever should be
+accomplished, Professor Weismann's elaborate theory of evolution will
+have had its bases removed.
+
+
+
+
+SECTION II
+
+_UTILITY_
+
+
+
+
+CHAPTER VII.
+
+CHARACTERS AS ADAPTIVE AND SPECIFIC.
+
+
+One of the great changes which has been wrought in biological science by
+the Darwinian theory of natural selection, consists in its having
+furnished an intelligible explanation of the phenomena of _adaptation_.
+Indeed, in my opinion, this is the most important function which this
+theory has had to perform; and although we still find systematic
+zoologists and systematic botanists who hold that the chief merit of
+Darwin's work consists in its having furnished an explanation of the
+origin of _species_, a very little consideration is enough to show that
+such an idea is but a survival, or a vestige, of an archaic system of
+thought. So long as species were regarded as due to separate acts of
+creation, any theory which could explain their production by a process
+of natural evolution became of such commanding importance in this
+respect, that we cannot wonder if in those days the principal function
+of Darwin's work was held to be what the title of that work--_The Origin
+of Species by means of Natural Selection_--itself serves to convey. And,
+indeed, in those days this actually was the principal function of
+Darwin's work, seeing that in those days the _fact_ of evolution
+itself, as distinguished from its _method_, had to be proved; and that
+the whole proof had to stand or fall with the evidence which could be
+adduced touching the mutability of species. Therefore, without question,
+Darwin was right in placing this issue as to the stability or
+instability of species in the forefront of his generalizations, and
+hence in constituting it the title of his epoch-making book. But
+nowadays, when the fact of evolution has been sufficiently established,
+one would suppose it self-evident that the theory of natural selection
+should be recognized as covering a very much larger field than that of
+explaining the origin of _species_--that it should be recognized as
+embracing the whole area of organic nature in respect of _adaptations_,
+whether these happen to be distinctive of species only, or of genera,
+families, orders, classes, and sub-kingdoms. For it follows from the
+general fact of evolution that species are merely arbitrary divisions,
+which present no deeper significance from a philosophical point of view
+than is presented by well-marked varieties, out of which they are in all
+cases believed to have arisen, and from which it is often a matter of
+mere individual taste whether they shall be separated by receiving the
+baptism of a specific name. Yet, although naturalists are now
+unanimously agreed that what they classify as species are nothing
+more than pronounced--and in some greater or less degree
+permanent--varieties, so forcible is the influence of traditional modes
+of thought, that many zoologists and botanists still continue to regard
+the origin of species as a matter of more importance than the origin of
+adaptations. Consequently, they continue to represent the theory of
+natural selection as concerned, primarily, with explaining the origin of
+species, and denounce as a "heretic" any one who regards the theory as
+primarily a theory of the origin and cumulative development of
+adaptations--whether structural or instinctive, and whether the
+adaptations are severally characteristic of species only or of any of
+the higher taxonomic divisions. Indeed, these naturalists appear to deem
+it in some way a disparagement of the theory to state that it is,
+primarily, a theory of adaptations, and only becomes secondarily a
+theory of species in those comparatively insignificant cases where the
+adaptations happen to be distinctive of the lowest order of taxonomic
+division--a view of the matter which may fitly be compared to that of an
+astronomer who should define the nebular hypothesis as a theory of the
+origin of Saturn's rings. It is indeed a theory of the origin of
+Saturn's rings; but only because it is a theory of the origin of the
+entire solar system, of which Saturn's rings form a part. Similarly, the
+theory of natural selection is a theory of the entire system of organic
+nature in respect of adaptations, whether these happen to be distinctive
+of particular species only, or are common to any number of species.
+
+Now the outcry which has been raised over this definition of the theory
+of natural selection is a curious proof of the opposition which may be
+furnished by habitual modes of thought to an exceedingly plain matter of
+definition. For, I submit, that no one can deny any of the following
+propositions; nor can it be denied that from these propositions the
+foregoing definition of the theory in question follows by way of
+necessity. The propositions are, first, that natural selection is taken
+to be the agency which is mainly, if not exclusively, concerned in the
+evolution of adaptive characters: secondly, that these characters, when
+evolved, are in some cases peculiar to single species only, while in
+other cases, and in process of time, they become the common property of
+many species: thirdly, that in cases where they are peculiar to single
+species only, they constitute at all events one of the reasons (or even,
+as the ultra-Darwinians believe, the only reason) why the particular
+species presenting them have come to be species at all. Now, these being
+the propositions on which we are all agreed, it obviously follows, of
+logical necessity, that the theory in question is primarily one which
+explains the existence of adaptive characters wherever these occur; and,
+therefore, whether they happen to be restricted to single species, or
+are common to a whole group of species. Of course in cases where they
+are restricted to single species, the theory which explains the origin
+of these particular adaptations becomes also a theory which explains the
+origin of these particular species; seeing that, as we are all agreed,
+it is in virtue of such particular adaptations that such particular
+species exist. Yet even in these cases the theory is, primarily, a
+theory of the adaptations in virtue of which the particular species
+exists; for, _ex hypothesi_, it is the adaptations which condition the
+species, not the species the adaptations. But, as just observed,
+adaptations may be the common property of whole groups of species; and
+thus the theory of natural selection becomes a theory of the origin of
+genera, of families, of orders, and of classes, quite as much as it is a
+theory of the origin of species. In other words, it is everywhere a
+theory of adaptations; and it is only where the adaptations happen to be
+restricted to single species that the theory therefore and incidentally
+becomes also a theory of the particular species which presents them.
+Hence it is by no means the same proposition to affirm that the theory
+of natural selection is a theory of the origin of species, and that it
+is a theory of the origin of adaptations, as some of my critics have
+represented it to be; for these two things are by no means conterminous.
+And in as far as the two propositions differ, it is perfectly obvious
+that the latter is the true one.
+
+Possibly, however, it may be said--Assuredly natural selection is a
+theory of the origin (i.e. cumulative development) of adaptations; and,
+no less assuredly, although species owe their origin to such
+adaptations, there is now no common measure between these two things,
+seeing that in numberless cases the same adaptations are the common
+property of numberless species. But, allowing all this, we must still
+remember that in their _first beginnings_ all these adaptations must
+have been distinctive of, or peculiar to, some one particular species,
+which afterwards gave rise to a whole genus, family, order, or class of
+species, all of which inherited the particular adaptations derived from
+this common ancestor, while progressively gaining additional adaptive
+characters severally distinctive of their subsequently diverging lines
+of descent. So that really all adaptive characters must originally have
+been specific characters; and therefore there is no real distinction to
+draw between natural selection as a theory of species and as a theory of
+adaptations.
+
+Well, if this objection were to be advanced, the answer would be
+obvious. Although it is true that every adaptive character which is now
+common to a group of species must originally have been distinctive of a
+single parent species, it by no means follows that in its first
+beginning as a specific character it appeared in the fully developed
+form which it now presents as a generic, family, ordinal, or yet higher
+character. On the contrary, it is perfectly certain that in the great
+majority of instances such cannot possibly have been the case; and the
+larger the group of species over which any particular adaptive character
+now extends, the more evidently do we perceive that this character must
+itself have been the product of a gradual evolution by natural selection
+through an innumerable succession of species in branching lines. The
+wing of a bird, for example, is an adaptive structure which cannot
+possibly have ever appeared suddenly as a merely specific character: it
+must have been slowly elaborated through an incalculable number of
+successive species, as these branched into genera, families, and orders
+of the existing class. So it is with other class distinctions of an
+adaptive kind; and so, in progressively lessening degrees, is it with
+adaptive characters of an ordinal, a family, or a generic value. That is
+to say, in _all_ cases where an adaptive structure is common to any
+considerable group of species, we meet with clear evidence that the
+structure has been the product of evolution through the ancestry of
+those species; and this evidence becomes increasingly cogent the higher
+the taxonomic value of the structure. Indeed, it may be laid down as a
+general rule, that the greater the _degree_ of adaptation the greater is
+its _diffusion_--both as regards the number of species which present it
+now, and the number of extinct species through which it has been handed
+down, in an ever ramifying extension and in an ever improving form.
+Species, therefore, may be likened to leaves: successive and transient
+crops are necessary for the gradual building up of adaptations, which,
+like the woody and permanent branches, grow continuously in importance
+and efficiency through all the tree of life. Now, in my view, it is the
+great office of natural selection to see to the growth of these
+permanent branches; and although natural selection has likewise had an
+enormously large share in the origination of each successive crop of
+leaves--nay, let it be granted to the ultra-Darwinians for the sake of
+argument, an exclusive prerogative in this respect--still, in my view,
+this is really the least important part of its work. Not as an
+explanation of those merely permanent varieties which we call species,
+but as an explanation of the adaptive machinery of organic nature, which
+has led to the construction both of the animal and vegetable kingdoms in
+all their divisions do I regard the Darwinian theory as one of the
+greatest generalizations in the history of science.
+
+       *       *       *       *       *
+
+I have dwelt thus at some length upon a mere matter of definition
+because, as we shall now find, although it is but a matter of
+definition, it is fraught with consequences of no small importance to
+the general theory of descent. Starting from an erroneous definition of
+the theory of natural selection as primarily a theory of the origin of
+species, both friends and foes of the theory have concluded that the
+principle of utility must by hypothesis be of universal occurrence so
+far as species are concerned; whereas, if once these naturalists were to
+perceive that their definition of the theory is erroneous, they would
+likewise perceive that their conclusion cannot follow deductively from
+the theory itself. If such a conclusion is to be established at all, it
+can only be by other and independent evidence of the inductive kind--to
+wit, by actual observation.
+
+Hence we see the importance of starting with an accurate definition of
+the theory before proceeding to examine the doctrine of utility as of
+universal application to species--a doctrine which, as just stated, has
+been habitually and expressly deduced from the theory. This doctrine
+occurs in two forms; or, more correctly, there are with reference to
+this subject two distinct doctrines, which partly coincide and partly
+exclude one another. First, it is held by some naturalists that all
+species must necessarily owe their origin to natural selection. And
+secondly, it is held by other naturalists, that not only all species,
+but likewise all specific characters must necessarily do the same. Let
+us consider these two doctrines separately.
+
+The first, and less extensive doctrine, rests on the deduction that
+every species must owe its differentiation as a species to the evolution
+of at least one adaptive character, which is peculiar to that species.
+Although, when thus originated, a species may come to present any
+number of other peculiar characters of a non-adaptive kind, these merely
+indifferent peculiarities are supposed to hang, as it were, on the peg
+supplied by the one adaptive peculiarity; it is the latter which
+conditions the species, and so furnishes an opportunity for any number
+of the former to supervene. But without the evolution of at least one
+adaptive character there could have been no distinct species, and
+therefore no merely adventitious characters as belonging to that
+species. I will call this the Huxleyan doctrine, because Professor
+Huxley is its most express and most authoritative supporter.
+
+The second and more extensive doctrine I will call, for the same reason,
+the Wallacean doctrine. This is, as already stated, that it follows
+deductively from the theory of natural selection, that not only all
+species, but even all the distinctive characters of every species, must
+necessarily be due to natural selection; and, therefore, can never be
+other than themselves useful, or, at the least, correlated with some
+other distinctive characters which are so.
+
+Here, however, I should like to remark parenthetically, that in choosing
+Professor Huxley and Mr. Wallace as severally representative of the
+doctrines in question, I earnestly desire to avoid any appearance of
+discourtesy towards such high authorities.
+
+I am persuaded--as I shall hereafter seek to show Darwin was
+persuaded--that the doctrine of utility as universal where species are
+concerned, is, in both the above forms, unsound. But it is less
+detrimental in its Huxleyan than in its Wallacean form, because it does
+not carry the erroneous deduction to so extreme a point. Therefore let
+us first consider the doctrine in its more restricted form, and then
+proceed, at considerably greater length, to deal with it in its more
+extended form.
+
+       *       *       *       *       *
+
+The doctrine that all _species_ must necessarily be due to natural
+selection, and therefore must severally present at least one adaptive
+character, appears to me doubly erroneous.
+
+In the first place, it is drawn from what I have just shown to be a
+false premiss; and, in the second place, the conclusion does not follow
+even from this premiss. That the premiss--or definition of the theory as
+primarily a theory of the origin of species--is false, I need not wait
+again to argue. That the conclusion does not follow even from this
+erroneous premiss, a very few words will suffice to prove. For, even if
+it were true that natural selection is primarily a theory of the origin
+of species, it would not follow that it must therefore be a theory of
+the origin of _all_ species. This would only follow if it were first
+shown that the theory is not merely _a_ theory of the origin of species,
+but _the_ theory of the origin of species--i.e. that there can be no
+further theory upon this subject, or any cause other than natural
+selection which is capable of transforming any single specific type.
+
+Needless to say, this cannot be shown by way of deduction from the
+theory of natural selection itself--which, nevertheless, is the only way
+whereby it is alleged that the doctrine is arrived at[86].
+
+    [86] For a full treatment of Professor Huxley's views upon this
+         subject, see Appendix II.
+
+       *       *       *       *       *
+
+From the doctrine of utility as advocated by Professor Huxley, we may
+now pass on to consider it in the much more comprehensive form advocated
+by Mr. Wallace. Of course it is obvious that if the doctrine is
+erroneous in its Huxleyan form, much more must it be so in its
+Wallacean; and, therefore, that having shown its erroneousness in its
+less extended application, there is little need to consider it further
+in its more extended form. Looking, however, to its importance in this
+more extended application, I think we ought to examine it independently
+as thus presented by Mr. Wallace and his school. Let us therefore
+consider, on its own merits, the following statement:--It follows
+directly from the theory of natural selection that not only all species,
+but likewise all specific characters, must be due to natural selection,
+and, therefore, must all be of use to the species which present them, or
+else correlated with other characters which are so.
+
+It seems worth while to observe, _in limine_, that this doctrine is
+contradicted by that of Professor Huxley. For supposing natural
+selection to be the only principle concerned in the origin of all
+species, it by no means follows that it is the sole agency concerned in
+the origin of all specific characters. It is enough for the former
+proposition if only some of the characters distinctive of any given
+species--nay, as he very properly expresses it, if only one such
+character--has been due to natural selection; for it is clear that, as
+he adds, "any number of indifferent [specific] characters" may thus have
+been furnished with an opportunity, so to speak, of being produced by
+causes other than natural selection. Hence, as previously remarked, the
+Huxleyan doctrine, although coinciding with the Wallacean up to the
+point of maintaining utility as the only principle which can be
+concerned in the origin of species, designedly excludes the Wallacean
+doctrine where this proceeds to extend any similar deduction to the case
+of specific characters[87].
+
+    [87] Professor Huxley's views upon this matter are quoted _in
+         extenso_ in Appendix II.
+
+In the next place, and with special reference to the Wallacean doctrine,
+it is of importance to observe that, up to a certain point there is
+complete agreement between Darwinists of all schools. We all accept
+natural selection as a true cause of the origin of species (though we
+may not all subscribe to the Huxleyan deduction that it is necessarily a
+cause of the origin of _all_ species). Moreover, we agree that specific
+characters are often what is called rudimentary or vestigial; and, once
+more, that our inability to detect the use of any given structure or
+instinct is no proof that such a structure or instinct is actually
+useless, seeing that it may very probably possess some function hitherto
+undetected, or possibly undetectable. Lastly, we all agree that a
+structure which is of use may incidentally entail the existence of some
+other structure which is not of use; for, in virtue of the so-called
+principle of correlation, the useless structure may be an indirect
+consequence of natural selection, since its development may be due to
+that of the useful structure, with the growth of which the useless one
+is correlated.
+
+Nevertheless, while fully conceding all these facts and principles to
+the Wallacean party, those who think with Professor Huxley--and still
+more, of course, those few naturalists who think as I do--are unable
+to perceive that they constitute any grounds for holding the doctrine
+that all specific _characters_ are, or formerly have been, directly or
+indirectly due to natural selection. My own reasons for dissenting from
+this Wallacean doctrine are as follows.
+
+       *       *       *       *       *
+
+From what has just been said, it will be apparent that the question in
+debate is not merely a question of fact which can be settled by a direct
+appeal to observation. If this were the case, systematic naturalists
+could soon settle the question by their detailed knowledge of the
+structures which are severally distinctive of any given group of
+species. But so far is this from being the case, that systematic
+naturalists are really no better qualified to adjudicate upon the matter
+than are naturalists who have not devoted so much of their time to
+purely diagnostic work. The question is one of general principles, and
+as such cannot be settled by appeals to special cases. For example,
+suppose that the rest of this chapter were devoted to a mere enumeration
+of cases where it appears impossible to suggest the utility of certain
+specific characters, although such cases could be adduced by the
+thousand, how should I be met at the end of it all? Not by any one
+attempting to suggest the utility, past or present, of the characters
+named; but by being told that they must all present some _hidden_ use,
+must be _vestigial_, or else must be due to _correlation_. By appealing
+to one or other of these assumptions, our opponents are always able to
+escape the necessity of justifying their doctrine in the presence of
+otherwise inexplicable facts. No matter how many seemingly "indifferent
+characters" we may thus accumulate, Mr. Wallace and his followers will
+always throw upon us the impossible burden of proving the negative, that
+these apparently useless characters do _not_ present some hidden or
+former use, are _not_ due to correlation, and therefore have _not_ been
+produced by natural selection. It is in vain to retort that the burden
+of proof really lies the other way, or on the side of those who affirm
+that there is utility where no man can see it, or that there is
+correlation where no one can detect it. Thus, so far as any appeal to
+particular facts is concerned, it does not appear that there is any
+_modus vivendi_. Our opinions upon the question are really determined by
+the views which we severally take on matters of general principle. The
+issue, though it has a biological bearing, is a logical issue, not a
+biological one: it turns exclusively on those questions of definition
+and deduction with which we have just been dealing.
+
+But although it thus follows that we cannot determine in fact what
+proportion of apparently useless characters are or are not really
+useful, we may very easily determine in fact what proportion of specific
+characters _fail to present any observable evidences of utility_. Yet,
+even upon this question of observable fact, it is surprising to note the
+divergent statements which have of late years been made by competent
+writers; statements in fact so divergent that they can only be explained
+by some want of sufficient thought on the part of those naturalists who
+are antecedently persuaded that all specific characters must be either
+directly or indirectly due to natural selection. Hence they fail to give
+to apparently useless specific characters the attention which, apart
+from any such antecedent persuasion, they deserve. For example, a few
+years ago I incidentally stated in a paper before the Linnaean Society,
+that "a large proportional number of specific characters" are of a
+trivial and apparently unmeaning kind, to which no function admits of
+being assigned, and also stated that Darwin himself had expressly given
+utterance to the same opinion. When these statements were made, I did
+not anticipate that they would be challenged by anybody, except perhaps,
+by Mr. Wallace. And, in order now to show that my innocence at that time
+was not due to ignorance of contemporary thought on such matters, a
+sentence may here be quoted from a paper which was read at the meeting
+of the British Association of the same year, by a highly competent
+systematic naturalist, Mr. Henry Seebohm, and soon afterwards
+extensively republished. Criticizing adversely my then recently
+published paper, he said:--
+
+     "I fully admit the truth of this statement; and I presume that few
+     naturalists would be prepared to deny that 'distinctions of
+     specific value frequently have reference to structures which are
+     without any utilitarian significance[88].'"
+
+    [88] _Geographical Distribution of the Family Charadriidae_, p. 19.
+
+But since that time the course of Darwinian speculation has been greatly
+influenced by the writings of Weismann, who, among other respects in
+which he out-darwins Darwin, maintains the doctrine of utility as
+universal. In consequence of the influence which these writings have
+exercised, I have been more recently and extensively accused of "heresy"
+to Darwinian principles, for having stated that "a large proportional
+number of specific characters" do not admit of being proved useful, or
+correlated with other characters that are useful. Now, observe, we have
+here a simple question of fact. We are not at present concerned with the
+question how far the argument from ignorance may be held to apply in
+mitigation of such cases; but we are concerned only with the question of
+fact, as to what proportional number of cases actually occur where we
+are _unable to suggest_ the use of specific characters, or the useful
+characters with which these apparently useless ones are correlated. I
+maintain, as a matter of fact, that the cases in question embrace "a
+large proportional number of specific characters." On the other hand, I
+am accused of betraying ignorance of species, and of the work of
+"species-makers," in advancing this statement; and have been told by Mr.
+Wallace, and others of his school, that there is absolutely no evidence
+to be derived from nature in support of my views. Well, in the first
+place, if this be the case, it is somewhat remarkable that a large body
+of competent naturalists, such as Bronn, Broca, Naegeli, Kerner, Sachs,
+De Vries, Focke, Henslow, Haeckel, Koelliker, Eimer, Giard, Pascoe,
+Mivart, Seebohm, Lloyd Morgan, Dixon, Beddard, Geddes Gulick, and also,
+as we shall presently see, Darwin himself, should have fallen into the
+same error. And it is further remarkable that the more a man devotes
+himself to systematic work in any particular department--whether as an
+ornithologist, a conchologist, an entomologist, and so forth--the less
+is he disposed to accept the dogma of specific characters as universally
+adaptive characters. But, in the second place, and quitting
+considerations of mere authority, I appeal to the facts of nature
+themselves; and will now proceed, as briefly as possible, to indicate
+the result of such an appeal.
+
+For the following reasons, that birds and mammals seem to furnish the
+best field for testing the question by direct observation. First, these
+classes present many genera which have been more carefully worked out
+than is usually the case with genera of invertebrates, or even of
+cold-blooded vertebrates. Secondly, they comprise many genera each
+including a large number of species, whose habits and conditions of life
+are better known than is the case with species belonging to large genera
+of other classes. Thirdly, as birds and mammals represent the highest
+products of evolution in respect of organization, a more severe test is
+imposed than could be imposed elsewhere, when the question is as to the
+utility of specific characters; for if these highest products of
+organization fail to reveal, in a large proportional number of cases,
+the utility of their specific characters, much more is this likely to be
+the case among organic beings which stand lower in the scale of
+organization, and therefore, _ex hypothesi_, are less elaborate products
+of natural selection. Fourthly, and lastly, birds and mammals are the
+classes which Mr. Wallace has expressly chosen to constitute his ground
+of argument with regard to the issue on which we are now engaged.
+
+It would take far too long to show, even in epitome, the results of this
+inquiry. Therefore I will only state the general upshot. Choosing genera
+of birds and mammals which contain a large number of species whose
+diagnostic characters have been worked out with most completeness, I
+restricted the inquiry to specific distinctions of colour, not only for
+the sake of having a uniform basis for comparisons, but still more
+because it seemed that the argument from our ignorance of possibly
+unknown uses could be more successfully met in the case of slight
+differences of colour or of shading, than in that of any differences of
+structure or of form. Finally, after tabulating all the differences of
+colour which are given as diagnostic of each species in a genus, and
+placing in one column those which may conceivably be useful, while
+placing in another column those of which it appeared inconceivable that
+any use could be suggested, I added up the figures in the two columns,
+and thus obtained a grand total of all the specific characters of the
+genus in respect of colours, separated into the two classes of
+conceivably useful and apparently useless. Now, in all cases the
+apparently useless characters largely preponderated over the conceivably
+useful ones; and therefore I abundantly satisfied myself regarding the
+accuracy of my previous statement, that a large proportional number--if
+not an actual majority--of specific characters belong to the latter
+category.
+
+The following is a brief abstract of these results.
+
+With respect to Birds, a large number of cases were collected wherein
+the characters of allied species differ from one another in such minute
+respects of colour or shading, that it seemed unreasonable to suppose
+them due to any selective value to the birds in question. It is
+needless--even if it were practicable on the present occasion--to
+adduce this evidence in detail, since an exceedingly good sample of it
+may be found in a small book which is specially devoted to considering
+the question in its relation to birds. I allude to an essay by Mr.
+Charles Dixon, entitled _Evolution without Natural Selection_ (1885). In
+this work Mr. Dixon embodies the results of five years' "careful working
+at the geographical distribution and variations of plumage of
+Palaearctic birds and their allies in various other parts of the world";
+and shows, by a large accumulation of facts, not only that there is no
+utility to be suggested in reference to the minute or trivial
+differences of colouration which he describes; but also that these
+differences are usually correlated with isolation on the one hand, or
+with slight differences of climate on the other. Now it will be shown
+later on that both these agents can be proved, by independent evidence,
+capable of inducing changes of specific type without reference to
+utility: therefore the correlation which Mr. Dixon unquestionably
+establishes between apparently useless (because utterly trivial)
+specific distinctions on the one hand, and isolation or climatic change
+on the other, constitutes additional evidence to show that the
+uselessness is not only apparent, but real. Moreover I have collected a
+number of cases where such minute differences of colour between allied
+species of birds happen to affect parts of the plumage which are
+_concealed_--as for instance, the breast and abdomen of creepers. In
+such cases it seems impossible to suggest how natural selection can have
+operated, seeing that the parts affected are not exposed to the view
+either of enemies or of prey.
+
+Analogous illustrations to any amount may be drawn from Mammals. For
+instance, I have worked through the Marsupials with the aid of Mr.
+Oldfield Thomas' diagnostic description of their numerous species. Now,
+let us take any one of the genera, such as the kangaroos. This comprises
+23 species living on an island continent of high antiquity, and not
+exposed to the depredations of any existing carnivorous enemies; so that
+there is here no present need to vary colour for purposes of protection.
+Moreover, in all cases the diagnostic distinctions of colour are so
+exceedingly trivial, that even if large carnivora were recently abundant
+in Australia, no one could reasonably suggest that the differences in
+question would then have been protective. On an average, each of the 23
+species presents rather more than 20 peculiarities of shading, which are
+quoted as specifically diagnostic. Altogether there are 474 of these
+peculiarities distributed pretty evenly among the 23 species; and in no
+case can I conceive that utility can be suggested.
+
+       *       *       *       *       *
+
+Hitherto we have been considering the question of fact, as to whether "a
+large proportional number of specific characters" do or do not admit of
+having their utility demonstrated, or even so much as plausibly
+suggested. In the result, I can only conclude that this question of fact
+is really not an open one, seeing that it admits of an abundantly
+conclusive answer by any naturalist who will take the trouble to work
+through the species of any considerable number of genera in the way
+above indicated. But although the question of fact is thus really
+closed, there remains a more ultimate question as to its theoretical
+interpretation. For, as already pointed out, no matter how great an
+accumulation of such facts may be collected, our opponents are always
+able to brush them aside by their _a priori_ appeal to the argument from
+ignorance. In effect they say--We do not care for any number of
+thousands of such facts; it makes no difference to us what "proportional
+number" of specific characters fail to show evidence of utility; you are
+merely beating the air by adducing them, for we are already persuaded,
+on antecedent grounds, that _all_ specific characters _must_ be either
+themselves useful, or correlated with others that are, whether or not we
+can perceive the utility, or suggest the correlation.
+
+To this question of theoretical interpretation, therefore, we must next
+address ourselves. And here, first of all, I should like to point out
+how sturdy must be the antecedent conviction of our opponents, if they
+are to maintain it in the face of such facts as have just been adduced.
+It must be remembered that this antecedent conviction is of a most
+uncompromising kind. By its own premisses it is committed to the
+doctrine that _all_ specific characters, without a single exception,
+_must_ be either useful, vestigial, or correlated. Well, if such be the
+case, is it not somewhat astonishing that out of 474 differences of
+colour which are distinctive of the 23 species of the genus Macropus, no
+single one appears capable of having any utility demonstrated, or indeed
+so much as suggested? For even the recent theory that slight differences
+of colour, which cannot be conceived as serving any other purpose, may
+enable the sexes of the same species quickly to recognize each other, is
+not here available. The species of the genus Macropus are more
+conspicuously distinguished by differences of size and form than by
+these minute differences of colour; and therefore no such use can be
+attributed to the latter. And, as previously stated, even within the
+order Marsupialia the genus Macropus is not at all exceptional in this
+respect; so that by including other genera of the order it would be easy
+to gather such apparently indifferent specific characters by the
+hundred, without any one of them presenting evidence--or even
+suggestion--of utility. How robust therefore is the faith of an _a
+priori_ conviction which can stand against such facts as these! What,
+then, are the _a priori_ grounds on which it stands? Mr. Wallace, the
+great leader of this school of thought, says:--
+
+     "It is a necessary deduction from the theory of natural selection,
+     that none of the definite facts of organic nature, no special
+     organ, no characteristic form or marking, no peculiarities of
+     instinct or of habit, no relations between species or between
+     groups of species, can exist, but which must now be, or once have
+     been, _useful_ to the individuals or the races which possess
+     them[89]."
+
+    [89] _Contributions to the Theory of Natural Selection_, p. 47
+         (1870); republished in 1892.
+
+Here, then, we have in brief compass the whole essence of our opponents'
+argument. It is confessedly an argument _a priori_, a deduction from the
+theory of natural selection, a supposed consequence of that theory which
+is alleged to be so necessary that to dispute the consequence is
+tantamount to denying the theory from which it is derived. In short, as
+before stated, it is a question of theory, not a question of fact: our
+difference of opinion is logical, not biological: it depends on our
+interpretation of principles, not on our observation of species. It will
+therefore be my endeavour to show that the reasoning in question is
+fallacious: that it is _not_ a necessary deduction from the theory of
+natural selection that no characteristic form or marking, no
+peculiarities of instinct or of habit, can exist, but which must now be,
+or once have been, useful, or correlated with some other peculiarity
+that is useful.
+
+"The tuft of hair on the breast of a wild turkey-cock _cannot be of any
+use_, and it is doubtful whether it can be ornamental in the eyes of the
+female bird;--indeed, had the tuft appeared under domestication, it
+would have been called a monstrosity[90]."
+
+    [90] _Origin of Species_, p. 70: italics mine.
+
+As a matter of common sense, unprejudiced by dogma, this appears to be a
+perfectly sound judgement; but if Wallace had asked Darwin to prove such
+a negative, Darwin could only have replied that it was for Wallace to
+prove the affirmative--and thus the issue would have been thrown back
+upon a discussion of general principles. Then Wallace would have
+said--"The assertion of inutility in the case of any organ or
+peculiarity which is not a rudiment or a correlation _is not, and can
+never be_, the statement of a fact, but _merely an expression of our
+ignorance of its purpose or origin_[91]." Darwin, however, would have
+replied:--"Our ignorance of the laws of variation is profound"; and
+while, on this account, we ought "to be extremely cautious in
+_pretending to decide what structures are now, or have formerly been, of
+use to each species_," in point of fact "there can be little doubt that
+the tendency to vary in the same manner has _often_ been so strong, that
+_all_ individuals of the same _species_ have been similarly modified
+_without the aid of any form of selection_[92]."
+
+    [91] _Darwinism_, p. 137: italics mine.
+
+    [92] _Origin of Species_, p. 72: Mr. Wallace himself quotes this
+         passage (_Darwinism_, p. 141); but says with regard to it "the
+         important word 'all' is probably an oversight." In the Appendix
+         (II), on Darwin's views touching the doctrine of utility I
+         adduce a number of precisely equivalent passages, derived from
+         all his different works on evolution, and _every one of them_
+         presenting "the important word 'all.'"
+
+It will be my endeavour in the following discussion to show that Darwin
+would have had an immeasurable advantage in this imaginary debate.
+
+To begin with, Wallace's deductive argument is a clear case of circular
+reasoning. We set out by inferring that natural selection is a cause
+from numberless cases of observed utility as an effect: yet, when "in a
+large proportional number" of cases we fail to perceive any imaginable
+utility, it is argued that nevertheless utility must be there, since
+otherwise natural selection could not have been the cause.
+
+Be it observed, in any given case we may properly anticipate utility as
+_probable_, even where it is not perceived; because there are already so
+enormous a number of cases where it is perceived, that, if the principle
+of natural selection be accepted at all, we must conclude with Darwin
+that it is "the _main_ means of modification." Therefore, in particular
+cases of unperceived utility we may take this antecedent probability as
+a guide in our biological researches--as has been done with such
+brilliant success both by Darwin and Wallace, as well as by many of
+their followers. But this is a very different thing from laying down the
+universal maxim, that in _all_ cases utility _must_ be present, whether
+or not we shall ever be able to detect it[93]. For this universal maxim
+amounts to an assumption that natural selection has been the
+"_exclusive_ means of modification." That it has been "the main means of
+modification" is proved by the generality of the observed facts of
+adaptation. That it has been "the exclusive means of modification," with
+the result that these facts are universal, cannot be thus proved by
+observation. Why, then, is it alleged? Confessedly it is alleged by way
+of deduction from the theory of natural selection itself. Or, as above
+stated, after having deduced the theory from the facts, it is sought to
+deduce the facts from the theory.
+
+    [93] See Introductory Chapter, p. 20.
+
+Thus far I have been endeavouring to show that the universality of
+adaptation cannot be inferred from its generality, or from the theory of
+natural selection itself. But, of course, the case would be quite
+different if there were any independent evidence--or rather, let us say,
+any logical argument--to show that natural selection is "the exclusive
+means of modification." For in this event it would no longer involve
+circular reasoning to maintain that all specific characters are likewise
+adaptive characters. It might indeed appear antecedently improbable that
+no other principle than natural selection can possibly have been
+concerned in the differentiation of those relatively permanent varieties
+which we call species--that in all the realm of organic nature, and in
+all the complexities of living processes, there is no room for any
+other influence in the production of change, even of the most trivial
+and apparently unmeaning kind. But if there were any good evidence or
+logical argument to the contrary, this antecedent presumption would have
+to give way; and the certainty that all specific characters are likewise
+adaptive characters would be determined by the cogency of such evidence
+or argument as could be adduced. In short, we are not entitled to
+conclude--and still less does it follow "as a necessary deduction from
+the theory of natural selection"--that all the details of specific
+differentiation must in every case be either useful, vestigial, or
+correlated, _unless it has been previously shown, by independent
+evidence, or accurate reasoning, that there is no room for any other
+principle of specific change_.
+
+This, apparently, is the central core of the question. Therefore I will
+now proceed to consider such arguments as have been adduced to prove
+that, other than natural selection, there _can_ have been no "means of
+modification." And, after having exhibited the worthlessness of these
+arguments, I will devote the next chapter to showing that, as a matter
+of observable fact, there _are_ a considerable number of other
+principles, which can be proved to be capable of producing such minute
+differences of form and colour as "in a large proportional number" of
+cases constitute diagnostic distinctions between species and species.
+
+First, then, for the reasons _a priori_--and they are confessedly _a
+priori_--which have been adduced to prove that natural selection has
+been what in Darwin's opinion it has not been,--"the _exclusive_ means
+of modification." Disregarding the Lamarckian factors--which, even if
+valid, have but little relation to the present question, seeing that
+they are concerned, almost exclusively, with the evolution of _adaptive_
+characters--it is alleged that natural selection must occupy the whole
+field, because no other principle of change can be allowed to operate in
+the presence of natural selection. Now, I fully agree that this
+statement may hold as regards any principle of change which is
+deleterious; but clearly it does not hold as regards any principle which
+is merely neutral. If any one were to allege that specific characters
+are frequently detrimental to the species presenting them, he would no
+doubt lay himself open to the retort that natural selection could not
+allow such characters to persist; or, which amounts to the same thing,
+that it _does_ "necessarily follow from the theory of natural selection"
+that specific characters can never be in any large number, or in any
+large measure, _harmful_ to the species presenting them. But where
+the statement is that specific characters are frequently
+_indifferent_--again to use Professor Huxley's term--the retort loses
+all its relevancy. No reason has ever been shown why natural selection
+should interfere with merely indifferent characters, supposing such to
+have been produced by any of the agencies which we shall presently have
+to consider. Therefore this argument--or rather assertion--goes for
+nothing.
+
+The only other argument I have met with on this side of the question is
+one that has recently been adduced by Mr. Wallace. He says:--
+
+     "One very weighty objection to the theory that _specific_
+     characters can ever be wholly useless appears to have been
+     overlooked by those who have maintained the frequency of such
+     characters, and that is, their almost necessary instability[94]."
+
+    [94] _Darwinism_, p. 138.
+
+This argument he proceeds to elaborate at considerable length, but fails
+to perceive what appears to me the obvious answer. Provided that the
+cause of the useless character is constant, there is no difficulty in
+understanding why the character is stable. Utility is not the only
+principle that can lead to stability: any other principle must do the
+same, provided that it acts for a sufficient length of time, and with a
+sufficient degree of uniformity, on all the individuals of a species.
+This is a consideration the cogency of which was clearly recognized by
+Darwin, as the following quotations will show. Speaking of unadaptive
+characters, he says they may arise as merely
+
+     "fluctuating variations, which sooner or later become _constant_
+     through the nature of the organism and of surrounding conditions,
+     _but not through natural selection_[95]."
+
+    [95] _Origin of Species_, p. 176: italics mine, as also in the
+         following.
+
+Elsewhere we read:--
+
+     "Each of the endless variations which we see in the plumage of our
+     fowls must have had some efficient cause; and if the _same_ cause
+     were to act _uniformly_ during a long series of generations on
+     _many_ individuals, _all_ probably would be modified in the same
+     manner."
+
+As special illustrations of this fact I may quote the following cases
+from Darwin's works.
+
+     "Dr. Bachman states that he has seen turkeys raised from the eggs
+     of wild species, lose their metallic tints, and become spotted in
+     the third generation. Mr. Yarrell many years ago informed me that
+     the wild ducks bred in St James' Park lost their true plumage
+     after a few generations. An excellent observer (Mr. Hewitt) ...
+     found that he could not breed wild ducks true for more than five or
+     six generations, as they proved so much less beautiful. The white
+     collar round the neck of the mallard became broader and more
+     irregular, and white feathers appeared in the duckling's wings
+     &c.[96]"
+
+    [96] _Var._ vol. ii. p. 250.
+
+Now, such cases--to which numberless others might be added--prove that
+even the subtle and inconspicuous causes incidental to domestication are
+capable of inducing changes of specific character quite as great, and
+quite as "stable," as any that in a state of nature are taken to
+constitute specific distinctions. Yet there can here be no suggestion of
+utility, inasmuch as the change takes place in the course of a few
+generations, and therefore without leaving time for natural selection to
+come into play--even if it ever could come into play among the sundry
+domesticated birds in question.
+
+But the facts of domestication also make for the same conclusion in
+another way--namely, by proving that when time enough _has_ been allowed
+for the production of useless changes of greater magnitude, such changes
+are not infrequently produced. And the value of this line of evidence is
+that, great as are the changes, it is impossible that either natural or
+artificial selection can have been concerned in their production. It
+will be sufficient to give two examples--both with regard to structure.
+
+The first I will render in the words whereby it has already been stated
+in my own paper on _Physiological Selection_, because I should like to
+take this opportunity of answering Mr. Wallace's objection to it.
+
+     "Elsewhere (_Origin of Species_, p. 158) Mr. Darwin points out that
+     modifications which appear to present obvious utility are often
+     found on further examination to be really useless. This latter
+     consideration, therefore, may be said to act as a foil to the one
+     against which I am arguing, namely, that modifications which appear
+     to be useless may nevertheless be useful. But here is a still more
+     suggestive consideration, also derived from Mr. Darwin's writings.
+     Among our domesticated productions changes of structure--or even
+     structures wholly new--not unfrequently arise, which are in every
+     way analogous to the apparently useless distinctions between wild
+     species. Take, for example, the following most instructive case:--
+
+     [Illustration: Fig. 2.--Old Irish Pig, showing jaw-appendages
+     (after Richardson).]
+
+     "'Another curious anomaly is offered by the appendages described by
+     M. Eudes-Deslongchamps as often characterizing the Normandy pigs.
+     These appendages are always attached to the same spot, to the
+     corners of the jaws; they are cylindrical, about three inches in
+     length, covered with bristles, and with a pencil of bristles rising
+     out of a sinus on one side; they have a cartilaginous centre with
+     two small longitudinal muscles; they occur either symmetrically on
+     both sides of the face, or on one side alone. Richardson figures
+     them on the gaunt old Irish Greyhound pig; and Nathusius states
+     that they occasionally appear in all the long-eared races, but are
+     not strictly inherited, for they occur or fail in the animals of
+     the same litter. As no wild pigs are known to have analogous
+     appendages, we have at present no reason to suppose that their
+     appearance is due to reversion; and if this be so, we are forced to
+     admit that a somewhat complex, though apparently useless, structure
+     may be suddenly developed without the aid of selection[97].'"
+
+    [97] _Variation_, &c. vol. i. pp. 78-79.
+
+To this case Mr. Wallace objects:--
+
+     "But it is expressly stated that they are not constant; they appear
+     'frequently' or 'occasionally,' they are 'not strictly inherited,
+     for they occur or fail in animals of the same litter'; and they are
+     not always symmetrical, sometimes appearing on one side of the face
+     alone. Now, whatever may be the cause or explanation of these
+     anomalous appendages, they cannot be classed with 'specific
+     characters,' the most essential features of which are, that they
+     _are_ symmetrical, that they _are_ inherited, and that they _are_
+     constant[98]."
+
+    [98] _Darwinism_, pp. 139-40.
+
+But, to begin with, I have not classed these appendages with "specific
+characters," nor maintained that Normandy pigs ought to be regarded as
+specifically distinct on account of them. What I said was:--
+
+     "Now, if any such structure as this occurred in a wild species, and
+     if any one were to ask what is the use of it, those who rely on the
+     argument from ignorance would have a much stronger case than they
+     usually have; for they might point to the cartilage supplied with
+     muscles, and supporting a curious arrangement of bristles, as much
+     too specialized a structure to be wholly meaningless. Yet we happen
+     to know that this particular structure is wholly meaningless[99]."
+
+    [99] Mr. Wallace deems the concluding words "rather confident." I
+         was not, however, before aware that he extended his _a priori_
+         views on utility to domesticated varieties which are bred for
+         the slaughter-house. If he now means to indicate that these
+         appendages are possibly due to natural selection, he is surely
+         going very far to save his _a priori_ dogma; and in the case
+         next adduced will have to go further still.
+
+In the next place, is it either fair or reasonable to expect that a
+varietal character of presumably very recent origin should be as
+strongly inherited--and therefore as constant both in occurrence and
+symmetry--as a true specific character, say, of a thousand times its
+age? Even characters of so-called "constant varieties" in a state of
+nature are usually less constant than specific characters; while, again,
+as Darwin says, "it is notorious that specific characters are more
+variable than generic,"--the reason in both cases being, as he proceeds
+to show, that the less constant characters are characters of more recent
+origin, and therefore less firmly fixed by heredity[100]. Hence I do not
+understand how Mr. Wallace can conclude, as he does, "that, admitting
+that this peculiar appendage is wholly useless and meaningless, the fact
+would be rather an argument against specific characters being also
+meaningless, because the latter never have the characteristics [i.e.
+inconstancy of occurrence, form, and transmission] which this particular
+variation possesses[101]." Mr. Wallace can scarcely suppose that when
+specific characters first arise, they present the three-fold kind of
+constancy to which he here alludes. But, if not, can it be denied that
+these peculiar appendages appear to be passing through a phase of
+development which all "specific characters" must have passed through,
+before they have had time enough to be firmly fixed by heredity[102]?
+
+    [100] _Origin of Species_, pp. 122-3.
+
+    [101] _Darwinism_, p. 140.
+
+    [102] In the next paragraph Mr. Wallace says that the appendages in
+          question "are apparently of the same nature as the 'sports'
+          that arise in our domesticated productions, but which, as Mr.
+          Darwin says, without the aid of selection would soon
+          disappear." But I cannot find that Mr. Darwin has made any
+          such statement: what he does say is, that whether or not a
+          useless peculiarity will soon disappear without the aid of
+          selection depends upon the nature of the causes which produce
+          it. If these causes are of a merely transitory nature, the
+          peculiarity will also be transitory; but if the causes be
+          constant, so will be the result. Again, the point to be
+          noticed about this "sport" is, that, unlike what is usually
+          understood by a "sport," it affects a whole race or breed, is
+          transmitted by sexual propagation, and has already attained so
+          definite a size and structure, that it can only be reasonably
+          accounted for by supposing the continued operation of _some
+          constant_ cause. This cause can scarcely be correlation of
+          growth, since closely similar appendages are often seen in so
+          different an animal as a goat. Here, also, they run in breeds
+          or strains, are strongly inherited, and more "constant," as
+          well as more "symmetrical" than they are in pigs. This, at all
+          events, is the account I have received of them from
+          goat-breeders in Switzerland.
+
+If, however, even this should be denied, what will be said of the second
+case, that of the niata cattle?
+
+     "I saw two herds on the northern bank of the Plata.... The forehead
+     is very short and broad, with the nasal end of the skull, together
+     with the whole plane of the upper molar-teeth, curved upwards. The
+     lower jaw projects beyond the upper, and has a corresponding upward
+     curvature.... The skull which I presented to the College of
+     Surgeons has been thus described by Professor Owen. 'It is
+     remarkable from the stunted development of the nasals,
+     premaxillaries, and fore part of the lower jaw, which is unusually
+     curved upwards to come into contact with the premaxillaries. The
+     nasal bones are about one-third the ordinary length, but retain
+     almost their normal breadth. The triangular vacuity is left between
+     them and the frontal and lachrymal, which latter bone articulates
+     with the premaxillary, and thus excludes the maxillary from any
+     junction with the nasal.' So that even the connexion of some of
+     the bones is changed. Other differences might be added: thus the
+     plane of the condyles is somewhat modified, and the terminal edge
+     of the premaxillaries forms an arch. In fact, on comparison with
+     the skull of a common ox, scarcely a single bone presents the same
+     exact shape, and the whole skull has a wonderfully different
+     appearance[103]."
+
+    [103] Darwin, _Variation_, &c., vol. i. pp. 92-4.
+
+[Illustration: Fig. 3.--Drawn from nature. R. Coll. Surg. Mus.]
+
+As I cannot find that this remarkable skull has been figured before, I
+have had the accompanying woodcut made in order to compare it with the
+skull of a Charsley Forest ox; and a glance is sufficient to show what
+"a wonderfully different appearance" it presents.
+
+       *       *       *       *       *
+
+Now the important points in the present connexion with regard to this
+peculiar race of cattle are the following.
+
+Their origin is not known; but it must have been subsequent to the year
+1552, when cattle were first introduced to America from Europe, and it
+is known that such cattle have been in existence for at least a century.
+The breed is very true, and a niata bull and cow invariably produce
+niata calves. A niata bull crossed with a common cow, and the reverse
+cross, yield offspring having an intermediate character, but with the
+niata peculiarities highly conspicuous[104].
+
+    [104] _Ibid._ p. 94.
+
+Here, then, we have unquestionable evidence of a whole congeries of very
+distinctive characters, so unlike anything that occurs in any other
+cattle, that, had they been found in a state of nature, they would have
+been regarded as a distinct species. And the highly peculiar characters
+which they present conform to all "the most essential features of
+specific characters," as these are stated by Mr. Wallace in his
+objection to the case of the pig's appendages. That is to say, "they
+_are_ symmetrical, they _are_ inherited, and they _are_ constant." In
+point of fact, they are _always_ "constant," both as to occurrence and
+symmetry, while they are so completely "inherited" that not only does "a
+niata bull and cow _invariably_ produce niata calves"; but even when
+crossed with other cattle the result is a _hybrid_, "with the niata
+character _strongly_ displayed."
+
+Hence, if we were to follow Mr. Wallace's criteria of specific
+characters, which show that the pig's appendages "cannot be classed with
+specific characters" (or with anything of the nature of specific
+characters), it would follow that the niata peculiarities _can_ be so
+classed. This, therefore, is a case where he will find all the reasons
+which in other cases he takes to justify him in falling back upon the
+argument from ignorance. The cattle are half wild, he may urge; and so
+the three-fold constancy of their peculiar characters may very well be
+due, either directly or indirectly, to natural selection--i.e. they may
+either be of some hidden use themselves, or correlated with some other
+modifications that are of use: it is, he may say, as in such cases he
+often does say, for us to disprove both these possibilities.
+
+Well, here we have one of those rare cases where historical information,
+or other accidents, admit of our discharging this burden of proving a
+negative. Darwin's further description shows that this customary refuge
+in the argument from ignorance is most effectually closed. For--
+
+     "When the pasture is tolerably long, these cattle feed as well as
+     common cattle with their tongue and palate; but during the great
+     droughts, when so many animals perish on the Pampas, the niata
+     breed lies under a great disadvantage, and would, if not attended
+     to, become extinct; for the common cattle, like horses, are able to
+     keep alive by browsing with their lips on the twigs of trees and on
+     reeds; this the niatas cannot so well do, as their lips do not
+     join, and hence they are found to perish before the common cattle.
+     This strikes me as a good illustration of how little we are able to
+     judge from the ordinary habits of an animal, on what circumstances,
+     occurring only at long intervals of time, its rarity or extinction
+     may depend. It shows us, also, how natural selection would have
+     determined the rejection of the niata modification, had it arisen
+     in a state of nature[105]."
+
+    [105] Darwin, _Variation_, &c. vol. i. p. 94.
+
+Hence, it is plainly _impossible_ to attribute this modification to
+natural selection, either as acting directly on the modified parts
+themselves, or indirectly through correlation of growth. And as the
+modification is of specific magnitude on the one hand, while it presents
+all "the most essential features of specific characters" on the other, I
+do not see any means whereby Mr. Wallace can meet it on his _a priori_
+principles. It would be useless to answer that these characters,
+although conforming to all his tests of specific characters, differ in
+respect of being deleterious, and would therefore lead to extermination
+were the animals in a wholly wild state; because, considered as an
+argument, this would involve the assumption that, apart from natural
+selection, only deleterious characters can arise under nature--i. e.
+that merely "indifferent" characters can never do so, which would be
+absurd. Indeed, I have chosen this case of the niata cattle expressly
+because their strongly marked peculiarities _are_ deleterious, and
+therefore exclude Mr. Wallace's appeal to the argument from ignorance of
+a possible utility. But if even these pronounced and deleterious
+peculiarities can arise and be perpetuated with such constancy and
+fidelity, much more is this likely to be the case with less pronounced
+and merely neutral peculiarities.
+
+It may, however, be further objected that these cattle are not
+improbably the result of _artificial_ selection. It may be suggested
+that the semi-monstrous breed originated in a single congenital
+variation, or "sport," which was isolated and multiplied as a curiosity
+by the early settlers. But even if such be the explanation of this
+particular case, the fact would not weaken our illustration. On the
+contrary, it would strengthen our general argument, by showing an
+additional means whereby indifferent specific characters can arise and
+become fixed in a state of nature. As it seems to me extremely probable
+that the niata cattle did originate in a congenital monstrosity, which
+was then isolated and multiplied by human agency (as is known to have
+been the case with the "ancon sheep"), I will explain why this tends to
+strengthen our general argument.
+
+It is certain that if these animals were ever subject to artificial
+isolation for the purpose of establishing their breed, the process must
+have ceased a long time ago, seeing that there is no memory or tradition
+of its occurrence. Now this proves that, however the breed may have
+originated, it has been able to maintain its many and highly peculiar
+characters for a number of generations without the help of selection,
+either natural or artificial. This is the first point to be clear upon.
+Be its origin what it may, we know that this breed has proved capable of
+perpetuating itself with uniform "constancy" for a number of generations
+after the artificial selection has ceased--supposing such a process ever
+to have occurred. And this certain fact that artificial selection, even
+if it was originally needed to establish the type, has not been needed
+to perpetuate the type, is a full answer to the supposed objection. For,
+in view of this fact, it is immaterial what the origin of the niata
+breed may have been. In the present connexion, the importance of this
+breed consists in its proving the subsequent "stability" of an almost
+monstrous form, continued through a long series of generations by the
+force of heredity alone, without the aid of any form of selection.
+
+The next point is, that not only is a seeming objection to the
+illustration thus removed, but that, if we do entertain the question of
+origin, and if we do suppose the origin of these cattle to have been in
+a congenital "sport," afterwards multiplied by artificial isolation, we
+actually strengthen our general argument by increasing the importance of
+this particular illustration. For the illustration then becomes
+available to show how indifferent specific characters may sometimes
+originate in merely individual sports, which, if not immediately
+extinguished by free intercrossing, will perpetuate themselves by the
+unaided force of heredity. But this is a point to which we shall recur
+in the ensuing chapter.
+
+In conclusion, it is worth while to remark, with regard to Mr. Wallace's
+argument from constancy, that, as a matter of fact, utility does not
+seem to present any greater power in securing "stability of characters"
+than any other cause of like constancy. Thus, for instance, whatever the
+causes may have been which have produced and perpetuated the niata breed
+of cattle, they have certainly produced a wonderful "stability" of a
+great modification in a wonderfully short time. And the same has to be
+said of the ducks in St. James' Park, as well as sundry other cases. On
+the other hand, when, as in the case of numberless natural species,
+modification has been undoubtedly produced by natural selection,
+although the modification must have had a very much longer time in which
+to have been fixed by heredity, it is often far from being
+stable--notwithstanding that Mr. Wallace regards stability as a
+criterion of specific characters. Indeed--and this is more suggestive
+still--there even seems to be a kind of _inverse_ proportion between the
+utility and the stability of a specific character. The explanation
+appears to be (_Origin of Species_, pp. 120-2), that the more a specific
+character has been forced on by natural selection on account of its
+utility, the less time will it have had to become well fixed by heredity
+before attaining a full development. Moreover, as Darwin adds, in cases
+where the modification has not only been thus "comparatively recent,"
+but also "extraordinarily great," the probability is that the parts so
+modified must have been very variable in the first instance, and so are
+all the more difficult to render constant by heredity. Thus we see that
+utility is no better--even if it be so good--a cause of stability in
+specific characters, as are the unknown causes of stability in many
+varietal characters[106].
+
+    [106] Should it be objected that useless characters, according to my
+          own view of the Cessation of Selection, ought to disappear,
+          and therefore cannot be constant, the answer is evident. For,
+          by hypothesis, it is only those useless characters which were
+          at one time useful that disappear under this principle.
+          Selection cannot cease unless it was previously present--i.e.
+          save in cases where the now useless character was originally
+          due to selection. Hence, in all cases where it was due to any
+          other cause, the useless character will persist at least as
+          long as its originating cause continues to operate. And even
+          after the latter (whatever it may be) has ceased to operate,
+          the useless character will but slowly degenerate, until the
+          eventual failure of heredity causes it to disappear _in
+          toto_--long before which time it may very well have become a
+          genetic, or some higher, character.
+
+
+
+
+CHAPTER VIII.
+
+CHARACTERS AS ADAPTIVE AND SPECIFIC
+(_continued_).
+
+
+Let us now proceed to indicate some of the causes, other than natural
+selection, which may be regarded as adequate to induce such changes in
+organic types as are taken by systematists to constitute diagnostic
+distinctions between species and species. We will first consider causes
+external to organisms, and will then go on to consider those which occur
+within the organisms themselves: following, in fact, the classification
+which Darwin has himself laid down. For he constantly speaks of such
+causes as arising on the one hand, from "changed conditions of life"
+and, on the other hand, from "the nature of the organism"--that is, from
+internal processes leading to "variations which seem to us in our
+ignorance to arise spontaneously."
+
+In neither case will it be practicable to give more than a brief
+_resume_ of all that might be said on these interesting topics.
+
+
+I. _Climate._
+
+There is an overwhelming mass of evidence to prove that the assemblage
+of external conditions of life conveniently summarized in the word
+Climate, exercise a potent, an uniform, and a permanent influence on
+specific characters.
+
+With regard to plants, Darwin adduces a number of facts to show the
+effects of climate on wheat, cabbages, and other vegetables. Here, for
+example, is what he says with regard to maize imported from America to
+Germany:--
+
+     "During the first year the plants were twelve feet high, and a few
+     seeds were perfected; the lower seeds in the ear kept true to their
+     proper form, but the upper seeds became slightly changed. In the
+     second generation the plants were from nine to ten feet high, and
+     ripened their seed better; the depression on the outer side of the
+     seed had almost disappeared, and the original beautiful white
+     colour had become duskier. Some of the seeds had even become
+     yellow, and in their now rounded form they approached the common
+     European maize. In the third generation nearly all resemblance to
+     the original and very distinct American parent-form was lost[107]."
+
+    [107] _Variation_, &c. vol. i. p. 340.
+
+As these "highly remarkable" changes were effected in but three
+generations, it is obvious that they cannot have been dependent on
+selection of any kind. The same remark applies to trees. Thus,--
+
+     "Mr. Meehan has compared twenty-nine kinds of American trees with
+     their nearest European allies, all grown in close proximity and
+     under as nearly as possible the same conditions. In the American
+     species he finds, with the rarest exceptions, that the leaves fall
+     earlier in the season, and assume before their fall a brighter
+     tint; that they are less deeply toothed or serrated; that the buds
+     are smaller; that the trees are more diffuse in growth and have
+     fewer branchlets; and, lastly, that the seeds are smaller--all in
+     comparison with the corresponding European species. Now,
+     considering that these corresponding trees belong to several
+     distinct orders, and that they are adapted to widely different
+     stations, it can hardly be supposed that their differences are of
+     any special service to them in the New and Old worlds; and, if so,
+     such differences cannot have been gained through natural selection,
+     and must be attributed to the long continued action of a different
+     climate[108]."
+
+    [108] _Variation_, &c. vol. ii. p. 271.
+
+These cases, however, I quote mainly in order to show Darwin's opinion
+upon the matter, with reference to the absence of natural selection.
+For, where the vegetable kingdom is concerned, the fact of climatic
+variation is so general, and in its relation to diagnostic work so
+important, that it constitutes one of the chief difficulties against
+which species-makers have to contend. And the more carefully the subject
+is examined the greater does the difficulty become. But, as to this and
+other general facts, it will be best to allow a recognized authority to
+speak; and therefore I will give a few extracts from Kerner's work on
+_Gute und schlechte Arten_.
+
+He begins by showing that geographical (or it may be topographical)
+varieties of species are often so divergent, that without a knowledge of
+intermediate forms there could be no question as to their being good
+species. As a result of his own researches on the subject, he can
+scarcely find language strong enough to express his estimate of the
+extent and the generality of this source of error. In different parts of
+Europe, or even in different parts of the Alps, he has found these
+climatic varieties in such multitudes and in such high degrees both of
+constancy and divergence, that, after detailing his results, he
+finishes his essay with the following remarkable conclusions:--
+
+     "Die Wissenchaft geht aber ihren Entwicklungsgang im grossen Ganzen
+     gerade so, wie die Erkenntniss bei jedem einzelnen Naturforscher.
+     Fast jeder Botaniker muss seinen Entwicklungsgang durchmachen und
+     gelangt endlich mehr oder weniger nahe zu demselben Ziele. Die
+     Ungleichheit besteht nur darin, dass der eine langsamer, der andere
+     aber rascher bei dem Ziele ankommt. Anfaenglich mueht sich jeder ab,
+     die Formen in hergebrachter Weise zu gliedern und die 'guten Arten'
+     herauszulesen. Mit der Erweiterung des Gesichtskreises und mit der
+     Vermehrung der Anschauungen aber schwindet auch immer mehr der
+     Boden unter den Fuessen, die bisher fuer unverrueckbar gehaltenen
+     Grenzen der gut geglaubten Arten stellen sich als eine der Natur
+     angelegte Zwangsjacke heraus, die Uebcrzeugung, dass die Grenzen,
+     welche wir ziehen, eben nur kuenstliche sind, gewinnt immer mehr und
+     mehr die Oberhand, und wer nicht gerade zu den hartgesottenen
+     Eigensinnigen gehoert, und wer die Wahrheit hoeher stellt als das
+     starre Festhalten an seinen frueheren Ansichten, geht schliesslich
+     bewusst oder unbewusst in das Lager derjenigen ueber, in welchem
+     auch ich mir ein bescheidenes Plaetzchen aufgesucht habe."
+
+By these "hard-boiled" botanists he means those who entertain the
+traditional notion of a species as an assemblage of definite
+characters, always and everywhere associated together. This notion
+(Artsbestaendigkeit) must be entirely abandoned. Summarizing Kerner's
+facts for their general results we find that his extensive
+investigations have proved that in his numberless kinds of European
+plants the following relations frequently obtain. Supposing that there
+are two or more allied species, A and B, then A' and B' may be taken to
+represent their respective types as found in some particular area. It
+does not signify whether A' and B' are geographically remote from, or
+close to, A and B; the point is that, whether in respect of temperature,
+altitude, moisture, character of soil, &c., there is some difference in
+the conditions of life experienced by the plants growing at the
+different places. Now, in numberless plants it is found that the typical
+or constant peculiarities of A' differ more from those of A than they do
+from those of B; while, conversely, the characters of A' may bear more
+resemblance to those of B' than they do to those of A--on account of
+such characters being due to the same external causes in both cases. The
+consequence is that A' might more correctly be classified with B', or
+_vice versa_. Another consequence is that whether A and B, or A' and B',
+be recorded as the "good species" usually depends upon which has
+happened to have been first described.
+
+Such a mere abstract of Kerner's general results, however, can give no
+adequate idea of their cogency: for this arises from the number of
+species in which specific characters are thus found to change, and even
+to _interchange_, with different conditions of life. Thus he gives an
+amusing parable of an ardent young botanist, Simplicius, who starts on a
+tour in the Tyrol with the works of the most authoritative systematists
+to assist him in his study of the flora. The result is that Simplicius
+becomes so hopelessly bewildered in his attempts at squaring their
+diagnostic descriptions with the facts of nature, that he can only
+exclaim in despair--"Sonderbare Flora, diese tirolische, in welcher so
+viele characteristische Pflanzen nur schlechte Arten, oder gar noch
+schlechter als schlechte Arten, sind." Now, in giving illustrations of
+this young man's troubles, Kerner fills five or six pages with little
+else than rows of specific names.
+
+Upon the whole, Kerner concludes that the more the subject is studied,
+the more convinced must the student become that all distinction between
+species as "good" and "bad" vanishes. In other words, the more that our
+knowledge of species and of their diagnostic characters increases, the
+more do we find that "bad species" multiply at the expense of "good
+species"; so that eventually we must relinquish the idea of "good
+species" altogether. Or, conversely stated, we must agree to regard as
+equally "good species" any and every assemblage of individuals which
+present the same peculiarities: provided that these peculiarities do not
+rise to a generic value, they equally deserve to be regarded as
+"specific characters," no matter how trivial, or how local, they may be.
+In fact, he goes so far as to say that when, as a result of experiments
+in transplantation from one set of physical conditions to another,
+seedlings are found to present any considerable and constant change in
+their specific characters, these seedlings are no less entitled to be
+regarded as a "good species" than are the plants from which they have
+been derived. Probably few systematists will consent to go quite so far
+as this; but the fact that Kerner has been led deliberately to propound
+such a statement as a result of his wide observations and experiments is
+about as good evidence as possible on the points with which we are here
+concerned. For even Simplicius would hardly be quite so simple as to
+suppose that each one of all the characters which he observes in his
+"remarkable flora," so largely composed of "bad or even worse than bad
+species," is of utilitarian significance.
+
+Be it noted, however, that I am not now expressing my own opinion. There
+are weighty reasons against thus identifying climatic variations with
+good species--reasons which will be dealt with in the next chapter.
+Kerner does not seem to appreciate the weight of these reasons, and
+therefore I do not call him as a witness to the subject as a whole; but
+only to that part of it which has to do with the great and general
+importance of climatic variability in relation to diagnostic work. And
+thus far his testimony is fully corroborated by every other botanist who
+has ever attended to the subject. Therefore it does not seem worth while
+to quote further authorities in substantiation of this point, such as
+Gaertner, De Candolle, Naegeli, Peter, Jordan, &c. For nowadays no one
+will dispute the high generality and the frequently great extent of
+climatic variation where the vegetable kingdom is concerned. Indeed, it
+may fairly be doubted whether there is any one species of plant, whose
+distribution exposes it to any considerable differences in its external
+conditions of life, which does not present more or less considerable
+differences as to its characters in different parts of its range. The
+principal causes of such climatic variation appear to be the chemical,
+and, still more, the mechanical nature of soil; temperature; intensity
+and diurnal duration of light in spring and summer; moisture; presence
+of certain salts in the air and soil of marine plants, or of plants
+growing near mineral springs; and sundry other circumstances of a more
+or less unknown character.
+
+Before closing these remarks on climatic variation in the vegetable
+kingdom, prominent attention must be directed to a fact of broad
+generality and, in relation to our present subject, of considerable
+importance. This is that the same external causes very frequently
+produce the same effects in the way of specific change throughout large
+numbers of _unrelated_ species--i.e. species belonging to different
+genera, families, and orders. Moreover, throughout all these unrelated
+species, we can frequently trace a uniform correlation between the
+degrees of change and the degrees to which they have been subjected to
+the causes in question.
+
+As examples, all botanists who have attended to the subject are struck
+by the similarity of variation presented by different species growing on
+the same soils, altitudes, latitudes, longitudes, and so forth. Plants
+growing on chalky soils, when compared with those growing on richer
+soils, are often more thickly covered with down, which is usually of a
+white or grey colour. Their leaves are frequently of a bluish-green
+tint, more deeply cut, and less veined, while their flowers tend to be
+larger and of a lighter tint. There are similarly constant differences
+in other respects in varieties growing on sundry other kinds of soils.
+Sea-salt has the general effect, on many different kinds of plants, of
+producing moist fleshy leaves, and red tints. Experiments in
+transplantation have shown that these changes may be induced
+artificially; so there can be no doubt as to its being this that and the
+other set of external conditions which produces them in nature. Again,
+dampness causes leaves to become smoother, greener, less cut, and the
+flowers to become darker; while dryness tends to produce opposite
+effects. I need not go on to specify the particular results on all kinds
+of plants of altitude, latitude, longitude, and so forth. For we are
+concerned only with the fact that these two correlations may be regarded
+as general laws appertaining to the vegetable kingdom--namely, (A) that
+the same external causes produce similar varietal effects in numerous
+unallied species of plants; and, (B) that the more these species are
+exposed to such causes the greater is the amount of varietal effect
+produced--so that, for instance, on travelling from latitude to
+latitude, longitude to longitude, altitude to altitude, &c., we may see
+greater and greater degrees of such definite and more or less common
+varietal changes affecting the unallied species in question. Now these
+general laws are of importance for us, because they prove unequivocally
+that it is the direct action of external conditions of life which
+produce climatic variations of specific types. And, taken in connexion
+with the results of experiments in transplantation (which in a single
+generation may yield variations similar to those found in nature under
+similar circumstances), these general laws still further indicate that
+climatic variations are "indifferent" variations. In other words, we
+find that changes of specific characters are of widespread occurrence in
+the vegetable kingdom, that they are constantly and even proportionally
+related to definite external circumstances, but yet that, in as far as
+they are climatic, they cannot be attributed to the agency of natural
+selection[109].
+
+    [109] Since the above paragraphs have been in type, the Rev. G.
+          Henslow has published his Linnaean Society papers which are
+          mentioned in the introductory chapter, and which deal in more
+          detail with this subject, especially as regards the facies of
+          desert floras.
+
+Turning next to animals, it may first be observed that climatic
+conditions do not appear to exercise an influence either so general or
+so considerable as in the case of plants. Nevertheless, although these
+influences are relatively more effective in the vegetable kingdom than
+they are in the animal, absolutely considered they are of high
+generality and great importance even in the latter. But as this fact is
+so well recognized by all zoologists, it will be needless to give more
+than a very few illustrations. Indeed, throughout this discussion on
+climatic influences my aim is merely to give the general reader some
+idea of their importance in regard to systematic natural history; and,
+therefore, such particular cases as are mentioned are selected only as
+samples of whole groups of cases more or less similar.
+
+With regard to animals, then, we may best begin by noticing that, just
+as in the case of plants, there is good evidence of the same external
+causes producing the same effects in multitudes of species belonging to
+different genera, families, orders, and even classes. Moreover, we are
+not without similarly good evidence of _degrees_ of specific change
+taking place in correlation with _degrees_ of climatic change, so that
+we may frequently trace a gradual progress of the former as we advance,
+say, from one part of a large continent to another. Instances of these
+correlations are not indeed so numerous in the animal kingdom as they
+are in the vegetable. Nevertheless they are amply sufficient for our
+present purposes.
+
+For example, Mr. Allen has studied in detail changes of size and colour
+among birds and mammals on the American continent; and he finds a
+wonderfully close sliding scale of both, corresponding stage by stage
+with gradual changes of climate. Very reasonably he attributes this to
+the direct influence of climatic conditions, without reference to
+natural selection--as does also Mr. Gould with reference to similar
+facts which he has observed among the birds of Australia. Against this
+view Mr. Wallace urges, "that the effects are due to the greater or less
+need of protection." But it is difficult to believe that such can be the
+case where so innumerable a multitude of widely different species are
+concerned--presenting so many diverse habits, as well as so many
+distinct habitats. Moreover, the explanation seems incompatible with the
+_graduated_ nature of the change, and also with the fact that not only
+colouration but size, is implicated.
+
+We meet with analogous facts in butterflies. Thus _Lycaena agestis_ not
+only presents seasonal variations, (A) and (B); but while (A) and (B)
+are respectively the winter and summer forms in Germany, (B) and (C) are
+the corresponding forms in Italy. Therefore, (B) is in Germany the
+summer form, and in Italy the winter form--the German winter form (A)
+being absent in Italy, while the Italian summer form (C) is absent in
+Germany. Probably these facts are due to differences of temperature in
+the two countries, for experiments have shown that when pupae of sundry
+species of moths and butterflies are exposed to different degrees of
+temperature, the most wonderful changes of colour may result in the
+insects which emerge. The remarkable experiments of Dorfmeister and
+Weismann in relation to this subject are well known. More recently Mr.
+Merrifield has added to their facts, and concludes that the action of
+cold upon the pupae--and also, apparently, upon the larvae--has a
+tendency to produce dark hues in the perfect insect[110].
+
+    [110] _Trans. Entom. Soc._ 1889, part i. p. 79 _et seq._
+
+But, passing now from such facts of climatic variations over wide areas
+to similar facts within small areas, in an important _Memoir on the Cave
+Fauna of North America_, published a few years ago by the American
+Academy of Sciences, it is stated:--
+
+     "As regards change of colour, we do not recall an exception to the
+     general rule that all cave animals are either colourless or nearly
+     white, or, as in the case of Arachnida and Insects, much paler than
+     their out-of-door relatives."
+
+Now, when we remember that these cave faunas comprise representatives of
+nearly all classes of the animal kingdom, it becomes difficult, if not
+impossible, to imagine that so universal a discharge of colouring can be
+due to natural selection. It must be admitted that the only way in which
+natural selection could act in this case would be indirectly through the
+principle of correlation. There being no light in the caves, it can be
+of no advantage to the animals concerned that they should lose their
+colour for the sake of protection, or for any other reason of a
+similarly direct kind. Therefore, if the loss of colour is to be
+ascribed to natural selection, this can only be done by supposing that
+natural selection has here acted indirectly through the principle of
+correlation. There is evidence to show that elsewhere modification or
+loss of colour is in some cases brought about by natural selection, on
+account of the original colour being correlated with certain
+physiological characters (such as liability to particular diseases,
+&c.); so that when natural selection operates directly upon these
+physiological characters, it thereby also operates indirectly upon the
+correlated colours. But to suppose that this can be the explanation of
+the uniform diminution of colour in all inhabitants of dark caves would
+be manifestly absurd. If there were only one class of animals in these
+caves, such as Insects, it might be possible to surmise that their
+change of colour is due to natural selection acting directly upon their
+physiological constitutions, and so indirectly upon their colours. But
+it would be absurd to suppose that such can be the explanation of the
+facts, when these extend in so similar a manner over so many scores of
+species belonging to such different types of animal life.
+
+With more plausibility it might be held that the universal discharge of
+colour in these cave-faunas is due, not to the presence, but to the
+absence of selection--i. e. to the cessation of selection, or panmixia.
+But against this--at all events as a full or general explanation--lie
+the following facts. First, in the case of Proteus--which has often been
+kept for the purposes of exhibition &c., in tanks--the skin becomes dark
+when the animal is removed from the cave and kept in the light.
+Secondly, deep-sea faunas, though as much exposed as the cave-faunas, to
+the condition of darkness, are not by any means invariably colourless.
+On the contrary, they frequently present brilliant colouration. Thus it
+is evident that if panmixia be suggested in explanation of the
+discharge of colouring in cave-faunas, the continuance of colour in
+deep-sea faunas appears to show the explanation insufficient. Thirdly,
+according to my view of the action of panmixia as previously explained,
+no _total_ discharge of colouration is likely to be caused by such
+action alone. At most the bleaching as a result of the mere withdrawal
+of selection would proceed only to some comparatively small extent.
+Fourthly, Mr. Packard in the elaborate _Memoir on Cave Fauna_, already
+alluded to, states that in some of the cases the phenomena of bleaching
+appear to have been induced within very recent times--if not, indeed,
+within the limits of a single generation. Should the evidence in support
+of this opinion prove trustworthy, of course in itself it disposes of
+any suggestion either of the presence or the absence of natural
+selection as concerned in the process.
+
+Nevertheless, I myself think it inevitable that to some extent the
+cessation of selection must have helped in discharging the colour of
+cave faunas; although for the reasons now given it appears to me that
+the main causes of change must have been of that direct order which we
+understand by the term climatic.
+
+As regards dogs, the Rev. E. Everest found it impossible to breed Scotch
+setters in India true to their type. Even in the second generation no
+single young dog resembled its parents either in form or shape. "Their
+nostrils were more contracted, their noses more pointed, their size
+inferior, and their limbs more slender[111]." Similarly on the coast of
+New Guinea, Bosman says that imported breeds of dogs "alter strangely;
+their ears grow long and stiff like those of foxes, to which colour they
+also incline ... and in three or four broods their barking turns into a
+howl[112]."
+
+    [111] _Variation_, &c. vol. i. p. 40.
+
+    [112] _Variation_, &c. vol. i. p. 40.
+
+Darwin gives numerous facts showing the effects of climate on horses,
+cattle, and sheep, in altering, more or less considerably, the
+characters of their ancestral stocks. He also gives the following
+remarkable case with regard to the rabbit. Early in the fifteenth
+century a common rabbit and her young ones were turned out on the island
+of Porto Santo, near Madeira. The feral progeny now differ in many
+respects from their parent stock. They are only about one-third of the
+weight, present many differences in the relative sizes of different
+parts, and have greatly changed in colour. In particular, the black on
+the upper surface of the tail and tips of the ears, which is so constant
+in all other wild rabbits of the world as to be given in most works as a
+specific character, has entirely disappeared. Again, "the throat and
+certain parts of the under surface, instead of being pure white, are
+generally grey or leaden colour," while the upper surface of the whole
+body is redder than in the common rabbit. Now, what answer have our
+opponents to make to such a case as this? Presumably they will answer
+that the case simply proves the action of natural selection during the
+best part of 400 years on an isolated section of a species. Although we
+cannot say of what use all these changes have been to the rabbits
+presenting them, nevertheless we _must_ believe that they have been
+produced by natural selection, and therefore _must_ present some hidden
+use to the isolated colony of rabbits thus peculiarly situated. Four
+centuries is long enough to admit of natural selection effecting all
+these changes in the case of so rapidly breeding an animal as the
+rabbit, and therefore it is needless to look further for any explanation
+of the facts. Such, I say, is presumably the answer that would be given
+by the upholders of natural selection as the only possible cause of
+specific change. But now, in this particular case it so happens that the
+answer admits of being conclusively negatived, by showing that the great
+assumption on which it reposes is demonstrably false. For Darwin
+examined two living specimens of these rabbits which had recently been
+sent from Porto Santo to the Zoological Gardens, and found them coloured
+as just described. Four years afterwards the dead body of one of them
+was sent to him, and then he found that the following changes had taken
+place. "The ears were plainly edged, and the upper surface of the tail
+was covered with blackish-grey fur, and the whole body was much less
+red; so that under the English climate this individual rabbit has
+recovered the proper colour of its fur in rather less than four years!"
+
+Mr. Darwin adds:--
+
+     "If the history of these Porto Santo rabbits had not been known,
+     most naturalists, on observing their much reduced size, their
+     colour, reddish above and grey beneath, their tails and ears not
+     tipped with black, would have ranked them as a distinct species.
+     They would have been strongly confirmed in this view by seeing them
+     alive in the Zoological Gardens, and hearing that they refused to
+     couple with other rabbits. Yet this rabbit, which there can be
+     little doubt would thus have been ranked as a distinct species, as
+     certainly originated since the year 1420[113]."
+
+    [113] _Variation_, &c. vol. i. p. 120.
+
+Moreover, it certainly originated as a direct result of climatic
+influences, independent of natural selection; seeing that, as soon as
+individual members of this apparently new species were restored to their
+original climate, they recovered their original colouration.
+
+As previously remarked, it is, from the nature of the case, an
+exceedingly difficult thing to prove in any given instance that natural
+selection has not been the cause of specific change, and so finally to
+disprove the assumption that it must have been. Here, however, on
+account of historical information, we have a crucial test of the
+validity of this assumption, just as we had in the case of the niata
+cattle; and, just as in their case, the result is definitely and
+conclusively to overturn the assumption. If these changes in the Porto
+Santo rabbits had been due to the gradual influence of natural selection
+guided by inscrutable utility, it is simply impossible that the same
+individual animals, in the course of their own individual life-times,
+should revert to the specific characters of their ancestral stock on
+being returned to the conditions of their ancestral climate. Therefore,
+unless any naturalist is prepared to contradict Darwin's statement that
+the changes in question amount to changes of specific magnitude, he can
+find no escape from the conclusion that distinctions of specific
+importance may be brought about by changes of habitat alone, without
+reference to utility, and therefore independently of natural selection.
+
+
+II. _Food._
+
+Although, as yet, little is definitely known on the subject, there can
+be no doubt that in the case of many animals differences of food induce
+differences of colour within the life-time of individuals, and therefore
+independently of natural selection.
+
+Thus, sundry definite varieties of the butterfly _Euprepia caja_ can be
+reared according to the different nourishment which is supplied to the
+caterpillar; and other butterflies are also known on whose colouring and
+markings the food of the caterpillar has great influence[114].
+
+    [114] See especially, Koch, _Die Raupen und Schmetterling der
+          Wetterau_, and _Die Schmetterling des Suedwestlichen
+          Deutschlands_, whose very remarkable results of numerous and
+          varied experiments are epitomized by Eimer, _Organic
+          Evolution_, Eng. Trans. pp. 147-153; also Poulton, _Trans.
+          Entom. Soc._ 1893.
+
+Again, I may mention the remarkable case communicated to Darwin by
+Moritz Wagner, of a species of _Saturnia_, some pupae of which were
+transported from Texas to Switzerland in 1870. The moths which emerged
+in the following year were like the normal type in Texas. Their young
+were supplied with leaves of _Juglans regia_, instead of their natural
+food, _J. nigra_; and the moths into which these caterpillars changed
+were so different from their parents, both in form and colour, "that
+they were reckoned by entomologists as a distinct species[115]."
+
+    [115] Mivart, _On Truth_, p. 378.
+
+With regard to mollusks, M. Costa tells us that English oysters, when
+turned down in the Mediterranean, "_rapidly_ became like the true
+Mediterranean oyster, altered their manner of growth, and formed
+prominent diverging rays." This is most probably due to some change of
+food. So likewise may be the even more remarkable case of _Helix
+nemoralis_, which was introduced from Europe to Virginia a few years
+ago. Under the new conditions it varied to such an extent that up to
+last year no less than 125 varieties had been discovered. Of these 67,
+or more than half, are new--that is, unknown in the native continent of
+the species[116].
+
+    [116] Cockerell, _Nature_, vol. xli. p. 393.
+
+In the case of Birds, the Brazilian parrot _Chrysotis festiva_ changes
+the green in its feathers to red or yellow, if fed on the fat of certain
+fishes; and the Indian Lori has its splendid colouring preserved by a
+peculiar kind of food (Wallace). The Bullfinch is well known to turn
+black when fed on hemp seeds, and the Canary to become red when fed on
+cayenne pepper (Darwin). Starting from these facts, Dr. Sauermann has
+recently investigated the subject experimentally; and finds that not
+only finches, but likewise other birds, such as fowls, and pigeons, are
+subject to similar variations of colour when fed on cayenne pepper; but
+in all cases the effect is produced only if the pepper is given to the
+young birds before their first moult. Moreover, he finds that a moist
+atmosphere facilitates the change of colour, and that the ruddy hue is
+discharged under the influence either of sunlight or of cold. Lastly, he
+has observed that sundry other materials such as glycerine and aniline
+dyes, produce the same results; so there can be no doubt that organic
+compounds probably occur in nature which are capable of directly
+affecting the colours of plumage when eaten by birds. Therefore the
+presence of such materials in the food-stuffs of birds occupying
+different areas may very well in many cases determine differences of
+colouration, which are constant or stable so long as the conditions of
+their production are maintained.
+
+
+III. _Sexual Selection._
+
+Passing on now to causes of specific change which are internal, or
+comprised within the organisms themselves, we may first consider the
+case of Sexual Selection.
+
+Mr. Wallace rejects the theory of sexual selection _in toto_, and
+therefore nothing that can be said under this head would be held by him
+to be relevant. Many naturalists, however, believe that Darwin was right
+in the large generalization which he published under this title; and in
+so far as any one holds that sexual selection is a true cause of
+specific modification, he is obliged to believe that innumerable
+specific characters--especially in birds and mammals--have been produced
+without reference to utility (other, of course, than utility for sexual
+purposes), and therefore without reference to natural selection. This is
+so obvious that I need not pause to dilate upon it. One remark, however,
+may be useful. Mr. Wallace is able to make a much more effective use of
+his argument from "necessary instability" when he brings it against the
+Darwinian doctrine of sexual selection, than he does when he brings it
+against the equally Darwinian doctrine of specific characters in general
+not being all necessarily due to natural selection. In the latter case,
+it will be remembered, he is easily met by showing that the causes of
+specific change other than natural selection, such as food, climate,
+&c., may be quite as general, persistent, and uniform, as natural
+selection itself; and therefore in this connexion Mr. Wallace's argument
+falls to the ground. But the argument is much more formidable as he
+brings it to bear against the theory of sexual selection. Here he asks,
+What is there to guarantee the uniformity and the constancy of feminine
+taste with regard to small matters of embellishment through thousands of
+generations, and among animals living on extensive areas? And, as we
+have seen in Part 1, it is not easy to supply an answer. Therefore this
+argument from the "necessary instability of character" is of
+immeasurably greater force as thus applied against Darwin's doctrine of
+sexual selection, than it is when brought against his doctrine that all
+specific characters need not necessarily be due to natural selection.
+Therefore, also, if any one feels disposed to attach the smallest degree
+of value to this argument in the latter case, consistency will require
+him to allow that in the former case it is simply overwhelming, or in
+itself destructive of the whole theory of sexual selection. And,
+conversely, if his belief in the theory of sexual selection can survive
+collision with this objection from instability, he ought not to feel any
+tremor of contact when the objection is brought to bear against his
+scepticism regarding the alleged utility of all specific characters. For
+assuredly no specific character which is apparent to our eyes can be
+supposed to be so refined and complex (and therefore so presumably
+inconstant and unstable), as are those minute changes of cerebral
+structure on which a psychological preference for all the refined
+shadings and many pigments of a complicated pattern must be held
+ultimately to depend. For this reason, then, as well as for those
+previously adduced, if any one agrees with Darwin in holding to the
+theory of sexual selection notwithstanding this objection from the
+necessary instability of unuseful embellishments, _a fortiori_ he ought
+to disregard the objection altogether in its relation to useless
+specific characters of other kinds.
+
+But quite apart from this consideration, which Mr. Wallace and his
+followers may very properly say does not apply to them, let us see what
+they themselves have made of the facts of secondary sexual
+characters--which, of course, are for the most part specific
+characters--in relation to the doctrine of utility.
+
+Mr. Wallace himself, in his last work, quotes approvingly a letter which
+he received in 1869 from the Rev. O Pickard-Cambridge, as follows:--
+
+     "I myself doubt that particular application of the Darwinian theory
+     which attributes male peculiarities of form, structure, colour, and
+     ornament to female appetency or predilection. There is, it seems to
+     me, undoubtedly something in the male organization of a special and
+     sexual nature, which, of its own vital force, develops the
+     remarkable male peculiarities so commonly seen, _and of no
+     imaginable use to that sex_. In as far as these peculiarities show
+     a great vital power, they point out to us the finest and strongest
+     individuals of the sex, and show us which of them would most
+     certainly appropriate to themselves the best and greatest number of
+     females, and leave behind them the strongest and greatest number of
+     progeny. And here would come in, as it appears to me, the proper
+     application of Darwin's theory of Natural Selection; _for the
+     possessors of greatest vital power being those most frequently
+     produced and reproduced, the external signs of it would go on
+     developing in an ever increasing exaggeration_, only to be checked
+     where it became really detrimental in some respect or other to the
+     individual[117]."
+
+    [117] _Darwinism_, pp.[typo: period missing in scan] 296-7: italics
+          mine.
+
+Here then the idea is, as more fully expressed by Mr. Wallace in the
+context, that all the innumerable, frequently considerable, and
+generally elaborate "peculiarities of form, structure, colour, and
+ornament," which Darwin attributed to sexual selection, are really due
+to "the laws of growth." Diverse, definite, and constant though these
+specific peculiarities be, they are all but the accidental or
+adventitious accompaniments of "vigour," or "vital power," due to
+natural selection. Now, without waiting to dispute this view, which has
+already been dealt with in the chapter on Sexual Selection in Part I, it
+necessarily follows that "a large proportional number of specific
+characters," which, while presenting "no imaginable use," are very much
+less remarkable, less considerable, less elaborate, &c., must likewise
+be due to this "correlation with vital power." But if the principle of
+correlation is to be extended in this vague and general manner, it
+appears to me that the difference between Mr. Wallace and myself, with
+respect to the principle of utility, is abolished. For of course no one
+will dispute that the prime condition to the occurrence of "specific
+characters," whether useful or useless, is the existence of some form
+which has been denominated a "species" to present them; and this is
+merely another way of saying that such characters cannot arise except in
+correlation with a general fitness due to natural selection. Or, to put
+the case in Mr. Wallace's own words--"This development [of useless
+specific characters] will necessarily proceed by the agency of natural
+selection [as a necessary condition] _and the general laws which
+determine the production of colour and of ornamental appendages_." The
+case, therefore, is just the same as if one were to say, for example,
+that all the ailments of animals and plants proceed from correlation
+with life (as a necessary condition), "and the general laws which
+determine the production" of ill-health, or of specific disease. In
+short, the word "correlation" is here used in a totally different sense
+from that in which it is used by Darwin, and in which it is elsewhere
+used by Wallace for the purpose of sustaining his doctrine of specific
+characters as necessarily useful. To say that a useless character A is
+correlated with a useful one B, is a very different thing from saying
+that A is "correlated with vital power," or with the general conditions
+to the existence of the species to which it belongs. So far as the
+present discussion is concerned, no exception need be taken to the
+latter statement. For it simply surrenders the doctrine against which I
+am contending.
+
+
+IV. _Isolation._
+
+It is the opinion of many naturalists who are well entitled to have an
+opinion upon the subject, that, in the words of Mr. Dixon, "Isolation
+can preserve a non-beneficial as effectually as natural selection can
+preserve a beneficial variation[118]." The ground on which this doctrine
+rests is thus clearly set forth by Mr. Gulick:--"The fundamental cause
+of this seems to lie in the fact that no two portions of a species
+possess exactly the same average characters; and, therefore, that the
+initial differences are for ever reacting on the environment and on each
+other in such a way as to ensure increasing divergence in each
+generation, as long as the individuals of the two groups are kept from
+intergenerating[119]." In other words, as soon as a portion of a species
+is separated from the rest of that species, so that breeding between the
+two portions is no longer possible, the general average of characters in
+the separated portion not being in all respects precisely the same as it
+is in the other portion, the result of in-breeding among all individuals
+of the separated portion will eventually be different from that which
+obtains in the other portion; so that, after a number of generations,
+the separated portion may become a distinct species from the effect of
+isolation alone. Even without the aid of isolation, any original
+difference of average characters may become, as it were, magnified in
+successive generations, provided that the divergence is not harmful to
+the individuals presenting it, and that it occurs in a sufficient
+proportional number of individuals not to be immediately swamped by
+intercrossing. For, as Mr. Murphy has pointed out, in accordance with
+Delboeuf's law, "if, in any species, a number of individuals, bearing a
+ratio not infinitely small to the entire number of births, are in every
+generation born with a particular variation which is neither beneficial
+nor injurious, and if it be not counteracted by reversion, then the
+proportion of the new variety to the original form will increase till it
+approaches indefinitely near to equality[120]." Now even Mr. Wallace
+himself allows that this must be the case; and thinks that in these
+considerations we may find an explanation of the existence of certain
+definite varieties, such as the melanic form of the jaguar, the brindled
+or ring-eyed guillemot, &c. But, on the other hand, he thinks that such
+varieties must always be unstable, and continually produced in varying
+proportions from the parent forms. We need not, however, wait to dispute
+this arbitrary assumption, because we can see that it fails, even as an
+assumption, in all cases where the superadded influence of isolation is
+concerned. Here there is nothing to intercept the original tendency to
+divergent evolution, which arises directly out of the initially
+different average of qualities presented by the isolated section of the
+species, as compared with the rest of that species[121].
+
+    [118] _Nature_, vol. xxxiii. p. 100.
+
+    [119] _Divergent Evolution through Cumulative Segregation_, Linn.
+          Journ. Zoology, vol. xx. p. 215.
+
+    [120] _Habit and Intelligence_, p. 241.
+
+    [121] Allusion may here again be made to the case of the niata
+          cattle. For here is a case where a very extreme variety is
+          certainly not unstable, nor produced in varying proportions
+          from the parent form. Moreover, as we have seen in the
+          preceding chapter, this almost monstrous variety most probably
+          originated as an individual sport--being afterwards maintained
+          and multiplied for a time by artificial selection. Now,
+          whether or not this was the case, we can very well see that it
+          may have been. Hence it will serve to illustrate another
+          possibility touching the origin and maintenance of useless
+          specific characters. For what is to prevent an individual
+          congenital variation of any kind (provided it be not harmful)
+          from perpetuating itself as a "varietal," and eventually,
+          should offspring become sufficiently numerous, a "specific
+          character"? There is nothing to prevent this, save panmixia,
+          or the presence of free intercrossing. But, as we shall see in
+          the next division of this treatise, there are in nature many
+          forms of isolation. Hence, as often as a small number of
+          individuals may have experienced isolation in any of its
+          forms, opportunity for perpetuation will have been given to
+          any congenital variations which may happen to arise. Should
+          any of these be pronounced variations, it would afterwards be
+          ranked as a specific character. I do not myself think that
+          this is the way in which indifferent specific characters
+          _usually_ originate. On the contrary, I believe that their
+          origin is most frequently due to the influence of isolation on
+          the average characters of the whole population, as briefly
+          stated in the text. But here it seems worth while to notice
+          this possibility of their occasionally arising as merely
+          individual variations, afterwards perpetuated by any of the
+          numerous isolating conditions which occur in nature. For, if
+          this can be the case with a varietal form so extreme as to
+          border on the monstrous, much more can it be so with such
+          minute differences as frequently go to constitute specific
+          distinctions. It is the business of species-makers to search
+          out such distinctions, no matter how trivial, and to record
+          them as "specific characters." Consequently, wherever in
+          nature a congenital variation happens to arise, and to be
+          perpetuated by the force of heredity alone under any of the
+          numerous forms of isolation which occur in nature, there will
+          be a case analogous to that of the niata cattle.
+
+As we shall have to consider the important principle of isolation more
+fully on a subsequent occasion, I need not deal with it in the present
+connexion, further than to remark that in this principle we have what
+appears to me a full and adequate condition to the rise and continuance
+of specific characters which need not necessarily be adaptive
+characters. And, when we come to consider the facts of isolation more
+closely, we shall find superabundant evidence of this having actually
+been the case.
+
+
+V. _Laws of Growth._
+
+Under this general term Darwin included the operation of all unknown
+causes internal to organisms leading to modifications of form or
+structure--such modifications, therefore, appearing to arise, as he says
+"spontaneously," or without reference to utility. That he attributed no
+small importance to the operation of these principles is evident from
+the last edition of the _Origin of Species_. But as these "laws of
+growth" refer to causes confessedly unknown, I will not occupy space by
+discussing this division of our subject--further than to observe that,
+as we shall subsequently see, many of the facts which fall under it are
+so irreconcilably adverse to the Wallacean doctrine of specific
+characters as universally adaptive, that in the face of them Mr. Wallace
+himself appears at times to abandon his doctrine _in toto_.
+
+
+
+
+CHAPTER IX.
+
+CHARACTERS AS ADAPTIVE AND SPECIFIC
+(_continued_).
+
+
+It must have appeared strange that hitherto I should have failed to
+distinguish between "true species" and merely "climatic varieties." But
+it will conduce to clearness of discussion if we consider our subject
+point by point. Therefore, having now given a fair statement of the
+facts of climatic variation, I propose to deal with their theoretical
+implications--especially as regards the distinction which naturalists
+are in the habit of drawing between them and so-called true species.
+
+First of all, then, what is this distinction? Take, for example, the
+case of the Porto Santo rabbits. To almost every naturalist who reads
+what has been said touching these animals, it will have appeared that
+the connexion in which they are adduced is wholly irrelevant to the
+question in debate. For, it will be said that the very fact of the
+seemingly specific differentiation of these animals having proved to be
+illusory when some of them were restored to their ancestral conditions,
+is proof that their peculiar characters are not specific characters; but
+only what Mr. Wallace would term "individual characters," or variations
+that are not _inherited_. And the same remark applies to all the other
+cases which have been adduced to show the generality and extent of
+climatic variation, both in other animals and also in plants. Why, then,
+it will be asked, commit the absurdity of adducing such cases in the
+present discussion? Is it not self-evident that however general, or
+however considerable, such merely individual, or non-heritable,
+variations may be, they cannot possibly have ever had anything to do
+with the origin of _species_? Therefore, is it not simply preposterous
+to so much as mention them in relation to the question touching the
+utility of specific characters?
+
+Well, whether or not it is absurd and preposterous to consider climatic
+variations in connexion with the origin of species, will depend, and
+depend exclusively, on what it is that we are to understand by a
+species. Hitherto I have assumed, for the sake of argument, that we all
+know what is meant by a species. But the time has now come for showing
+that such is far from being the case. And as it would be clearly absurd
+and preposterous to conclude anything with regard to specific characters
+before agreeing upon what we mean by a character as specific, I will
+begin by giving all the logically possible definitions of a species.
+
+1. _A group of individuals descended by way of natural generation from
+an originally and specially created type._
+
+This definition may be taken as virtually obsolete.
+
+2. _A group of individuals which, while fully fertile_ inter se, _are
+sterile with all other individuals--or, at any rate, do not generate
+fully fertile hybrids._
+
+This purely physiological definition is not nowadays entertained by any
+naturalist. Even though the physiological distinction be allowed to
+count for something in otherwise doubtful cases, no systematist would
+constitute a species on such grounds alone. Therefore we need not
+concern ourselves with this definition, further than to observe that it
+is often taken as more or less supplementary to each of the following
+definitions.
+
+3. _A group of individuals which, however many characters they share
+with other individuals, agree in presenting one or more characters of a
+peculiar kind, with some certain degree of distinctness._
+
+In this we have the definition which is practically followed by all
+naturalists at the present time. But, as we shall presently see more
+fully, it is an extremely lax definition. For it is impossible to
+determine, by any fixed and general rule, what degree of distinctness on
+the part of peculiar characters is to be taken as a uniform standard of
+specific separation. So long as naturalists believed in special
+creation, they could feel that by following this definition (3) they
+were at any rate doing their best to tabulate very real distinctions in
+nature--viz. between types as originally produced by a supernatural
+cause, and as subsequently more or less modified (i.e. within the limits
+imposed by the test of cross-fertility) by natural causes. But
+evolutionists are unable to hold any belief in such real distinctions,
+being confessedly aware that all distinctions between species and
+varieties are purely artificial. So to speak, they well know that it is
+they themselves who create species, by determining round what degrees of
+differentiation their diagnostic boundaries shall be drawn. And, seeing
+that these degrees of differentiation so frequently shade into one
+another by indistinguishable stages (or, rather, that they _always_ do
+so, unless intermediate varieties have perished), modern naturalists are
+well awake to the impossibility of securing any approach to a uniform
+standard of specific distinction. On this account many of them feel a
+pressing need for some firmer definition of a species than this
+one--which, in point of fact, scarcely deserves to be regarded as a
+definition at all, seeing that it does not formulate any definite
+criterion of specific distinctness, but leaves every man to follow his
+own standards of discrimination. Now, as far as I can see, there are
+only two definitions of a species which will yield to evolutionists the
+steady and uniform criterion required. These two definitions are as
+follows.
+
+4. _A group of individuals which, however many characters they share
+with other individuals, agree in presenting one or more characters of a
+peculiar and hereditary kind, with some certain degree of distinctness._
+
+It will be observed that this definition is exactly the same as the last
+one, save in the addition of the words "and hereditary." But, it is
+needless to say, the addition of these words is of the highest
+importance, inasmuch as it supplies exactly that objective and rigid
+criterion of specific distinctness which the preceding definition lacks.
+It immediately gets rid of the otherwise hopeless wrangling over species
+as "good" and "bad," or "true" and "climatic," of which (as we have
+seen) Kerner's essay is such a remarkable outcome. Therefore
+evolutionists have more and more grown to lay stress on the hereditary
+character of such peculiarities as they select for diagnostic features
+of specific distinctness. Indeed it is not too much to say that, at the
+present time, evolutionists in general recognize this character as,
+theoretically, indispensable to the constitution of a species. But it is
+likewise not too much to say that, practically, no one of our systematic
+naturalists has hitherto concerned himself with this matter. At all
+events, I do not know of any who has ever taken the trouble to ascertain
+by experiment, with regard to any of the species which he has
+constituted, whether the peculiar characters on which his diagnoses have
+been founded are, or are not, hereditary. Doubtless the labour of
+constituting (or, still more, of _re_-constituting) species on such a
+basis of experimental inquiry would be insuperable; while, even if it
+could be accomplished, would prove undesirable, on account of the chaos
+it would produce in our specific nomenclature. But, all the same, we
+must remember that this nomenclature as we now have it--and, therefore,
+the partitioning of species as we have now made them--has no reference
+to the criterion of heredity. Our system of distinguishing between
+species and varieties is not based upon the definition which we are now
+considering, but upon that which we last considered--frequently coupled,
+to some undefinable extent, with No. 2.
+
+5. There is, however, yet another and closer definition, which may be
+suggested by the ultra-Darwinian school, who maintain the doctrine of
+natural selection as the only possible cause of the origin of species,
+namely:--
+
+_A group of individuals which, however many characters they share with
+other individuals, agree in presenting one or more characters of a
+peculiar, hereditary, and adaptive kind, with some certain degree of
+distinctness._
+
+Of course this definition rests upon the dogma of utility as a necessary
+attribute of characters _qua_ specific--i.e. the dogma against which the
+whole of the present discussion is directed. Therefore all I need say
+with reference to it is, that at any rate it cannot be adduced in any
+argument where the validity of its basal dogma is in question. For it
+would be a mere begging of this question to argue that every species
+must present at least one peculiar and adaptive character, because,
+according to definition, unless an organic type does present at least
+one such character, it is not a specific type. Moreover, and quite apart
+from this, it is to be hoped that naturalists as a body will never
+consent to base their diagnostic work on what at best must always be a
+highly speculative extension of the Darwinian theory. While, lastly, if
+they were to do so with any sort of consistency, the precise adaptation
+which each peculiar character subserves, and which because of this
+adaptation is constituted a character of specific distinction, would
+have to be determined by actual observation. For no criterion of
+specific distinction could be more vague and mischievous than this one,
+if it were to be applied on grounds of mere inference that such and such
+a character, because seemingly constant, must "necessarily" be either
+useful, vestigial, or correlated.
+
+Such then, as far as I can see, are all the definitions of a species
+that are logically possible[122]. Which of them is chosen by those who
+maintain the necessary usefulness of all specific characters? Observe,
+it is for those who maintain this doctrine to choose their definition:
+it is not for me to do so. My contention is, that the term does not
+admit of any definition sufficiently close and constant to serve as a
+basis for the doctrine in question--and this for the simple reason that
+species-makers have never agreed among themselves upon any criterion of
+specific distinction. My opponents, on the other hand, are clearly bound
+to take an opposite view, because, unless they suppose that there is
+some such definition of a species, they would be self-convicted of the
+absurdity of maintaining a great generalization on a confessedly
+untenable basis. For example, a few years ago I was allowed to raise a
+debate in the Biological Section of the British Association on the
+question to which the present chapters are devoted. But the debate ended
+as I had anticipated that it must end. No one of the naturalists present
+could give even the vaguest definition of what was meant by a
+species--or, consequently, of a character as specific. On this account
+the debate ended in as complete a destruction as was possible of the
+doctrine that all the distinctive characters of every species must
+necessarily be useful, vestigial, or correlated. For it became
+unquestionable that the same generalization admitted of being made, with
+the same degree of effect, touching all the distinctive characters of
+every "snark."
+
+    [122] It is almost needless to say that by a definition as "logical"
+          is meant one which, while including all the differentiae of
+          the thing defined, excludes any qualities which that thing may
+          share in common with any other thing. But by definitions as
+          "logically possible" I mean the number of separate definitions
+          which admit of being correctly given of the same thing from
+          different points of view. Thus, for instance, in the present
+          case, since the above has been in type the late M.
+          Quatrefages' posthumous work on _Darwin et ses Precurseurs
+          Francais_ has been published, and gives a long list of
+          definitions of the term "species" which from time to time have
+          been enunciated by as many naturalists of the highest standing
+          as such (pp. 186-187). But while none of these twenty or more
+          definitions is logical in the sense just defined, they all
+          present one or other of the differentiae given by those in the
+          text.
+
+Probably, however, it will be thought unfair to have thus sprung a
+difficult question of definition in oral debate. Therefore I allude to
+this fiasco at the British Association, merely for the purpose of
+emphasizing the necessity of agreeing upon some definition of a species,
+before we can conclude anything with regard to the generalization of
+specific characters as necessarily due to natural selection. But when a
+naturalist has had full time to consider this fundamental matter of
+definition, and to decide on what his own shall be, he cannot complain
+of unfairness on the part of any one else who holds him to what he thus
+says he means by a species. Now Mr. Wallace, in his last work, has given
+a matured statement of what it is that he means by a species. This,
+therefore, I will take as the avowed basis of his doctrine touching the
+necessary origin and maintenance of all specific characters by natural
+selection. His definition is as follows:--
+
+     "An assemblage of individuals which have become somewhat modified
+     in structure, form, and constitution, _so as to adapt them to
+     slightly different conditions of life_; which can be differentiated
+     from allied assemblages; which reproduce their like; which usually
+     breed together; and, perhaps, when crossed with their near allies,
+     always produce offspring which are more or less sterile _inter
+     se_[123]."
+
+    [123] Darwinism, p. 167.
+
+From this definition the portion which I have italicized must be omitted
+in the present discussion, for the reasons already given while
+considering definition No. 5. What remains is a combination of Nos. 2
+and 4. According to Mr. Wallace, therefore, our criterion of a species
+is to be the heredity of peculiar characters, combined, perhaps, with a
+more or less exclusive fertility of the component individuals _inter
+se_. This is the basis on which his generalization of the utility of
+specific characters as necessary and universal is reared. Here, then, we
+have something definite to go upon, at all events as far as Mr. Wallace
+is concerned. Let us see how far such a basis of definition is competent
+to sustain his generalization.
+
+First of all it must be remarked that, as species have actually been
+constituted by systematists, the test of exclusive fertility does not
+apply. For my own part I think this is to be regretted, because I
+believe that such is the only natural--and therefore the only
+firm--basis on which specific distinctions can be reared. But, as
+previously observed, this is not the view which has been taken by our
+species-makers. At most they regard the physiological criterion as but
+lending some additional weight to their judgement upon morphological
+features, in cases where it is doubtful whether the latter alone are of
+sufficient distinctness to justify a recognition of specific value. Or,
+conversely, if the morphological features are clearly sufficient to
+justify such a recognition, yet if it happens to be known that there is
+full fertility between the form presenting them and other forms which do
+not, then the latter fact will usually prevent naturalists from
+constituting the well differentiated form a species on grounds of its
+morphological features alone--as, for instance, in the case of our
+domesticated varieties. In short, the physiological criterion has not
+been employed with sufficient closeness to admit of its being now
+comprised within any practical definition of the term "species"--if by
+this term we are to understand, not what any one may think species
+_ought to be_, but what species actually _are_, as they have been
+constituted for us by their makers.
+
+From all this it follows that the definition of the term "species" on
+which Mr. Wallace relies for his deduction with respect to specific
+characters, is the definition No. 4. In other words, omitting his
+_petitio principii_ and his allusion to the test of fertility, the great
+criterion in his view is the criterion of Heredity. And in this all
+other evolutionists, of whatever school, will doubtless agree with him.
+They will recognize that it is really the distinguishing test between
+"climatic varieties" and "true species," so that however widely or
+however constantly the former may diverge from one another in regard to
+their peculiar characters, they are not to be classed among the latter
+unless their peculiar characters are likewise hereditary characters.
+
+Now, if we are all agreed so far, the only question that remains is
+whether or not this criterion of Heredity is capable of supplying a
+basis for the generalization, that all characters which have been ranked
+as of specific value must necessarily be regarded as presenting also an
+adaptive, or life-serving, value? I will now endeavour to show that
+there are certain very good reasons for answering this question in the
+negative.
+
+
+(A.)
+
+In the first place, even if the modifications induced by the direct
+action of a changed environment are not hereditary, who is to know that
+they are not? Assuredly not the botanist or zoologist who in a
+particular area finds what he is fully entitled to regard as a
+well-marked specific type. Only by experiments in transposition could it
+be proved that the modifications have been produced by local conditions;
+and although the researches of many experimentalists have shown how
+considerable and how constant such modifications may be, where is the
+systematic botanist who would ever think of transplanting an apparently
+new species from one distant area to another before he concludes that it
+is a new species? Or where is the systematic zoologist who would take
+the trouble to transport what appears to be an obviously endemic species
+of animal from one country to another before venturing to give it a new
+specific name? No doubt, both in the case of plants and animals, it is
+tacitly assumed that constant differences, if sufficient in amount to be
+regarded as specific differences are hereditary; but there is not one
+case in a hundred where the validity of this assumption has ever been
+tested by experiments in transposition. Therefore naturalists are apt to
+regard it as remarkable when the few experiments which have been made in
+this direction are found to negative their assumption--for example,
+that a diagnostic character in species of the genus _Hieratium_ is found
+by transplantation not to be hereditary, or that the several named
+species of British trout are similarly proved to be all "local
+varieties" of one another. But, in point of fact, there ought to be
+nothing to surprise us in such results--unless, indeed, it is the
+unwarrantable nature of the assumption that any given differences of
+size, form, colour, &c., which naturalists may have regarded as of
+specific value, are, on this account, hereditary. Indeed, so surprising
+is this assumption in the face of what we know touching both the extent
+and the constancy of climatic variation, that it seems to me such a
+naturalist as Kerner, who never considers the criterion of heredity at
+all, is less assailable than those who profess to constitute this their
+chief criterion of specific distinction. For it is certain that whatever
+their professions may have nowadays become, systematic naturalists have
+never been in the habit of really following this criterion. In theory
+they have of late years attached more and more weight to definition No.
+4; but in practice they have always adopted definition No. 3. The
+consequence is, that in literally numberless cases (particularly in the
+vegetable kingdom) "specific characters" are assumed to be hereditary
+characters merely because systematic naturalists have bestowed a
+specific name on the form which presents them. Nor is this all. For,
+conversely, even when it is known that constant morphological characters
+are unquestionably hereditary characters, if they happen to present but
+small degrees of divergence from those of allied forms, then the form
+which presents them is not ranked as a species, but as a constant
+variety. In other words, when definitions 3 and 4 are found to clash, it
+is not 4, but 3, that is followed. In short, even up to the present
+time, systematic naturalists play fast and loose with the criterion of
+Heredity to such an extent, that, as above observed, it has been
+rendered wellnigh worthless in fact, whatever may be thought of it in
+theory.
+
+Now, unless all this can be denied, what is the use of representing that
+a species is distinguished from a variety--"climatic" or otherwise--by
+the fact that its constituent individuals "reproduce their like"? We are
+not here engaged on any abstract question of what might have been the
+best principles of specific distinction for naturalists to have adopted.
+We are engaged on the practical question of the principles which they
+actually have adopted. And of these principles the reproduction of like
+by like, under all circumstances of environment, has been virtually
+ignored.
+
+
+(B.)
+
+In the second place, supposing that the criterion of Heredity had been
+as universally and as rigidly employed by our systematists in their work
+of constructing species as it has been but occasionally and loosely
+employed, could it be said that even then a basis would have been
+furnished for the doctrine that all specific characters must necessarily
+be useful characters? Obviously not, and for the following reasons.
+
+It is admitted that climatic characters are not necessarily--or even
+generally--useful characters. Consequently, if there be any reason for
+believing that climatic characters may become in time hereditary
+characters, the doctrine in question would collapse, even supposing that
+all specific types were to be re-constituted on a basis of experimental
+inquiry, for the purpose of ascertaining which of them conform to the
+test of Heredity. Now there are very good reasons for believing that
+climatic characters not unfrequently do become hereditary characters;
+and it was mainly in view of those reasons that I deemed it worth while
+to devote so much space in the preceding chapter to the facts of
+climatic variation. I will now state the reasons in question under two
+different lines of argument.
+
+We are not as yet entitled to conclude definitely against the possible
+inheritance of acquired characters. Consequently, we are not as yet
+entitled to assume that climatic characters--i. e. characters acquired
+by converse with a new environment, continued, say, since the last
+glacial period--can never have become congenital characters. But, if
+they ever have become congenital characters, they will have become, at
+all events as a general rule, congenital characters that are useless;
+for it is conceded that, _qua_ climatic characters, they have not been
+due to natural selection.
+
+Doubtless the followers of Weismann will repudiate this line of
+argument, if not as entirely worthless, at all events as too
+questionable to be of much practical worth. But even to the followers of
+Weismann it may be pointed out, that the Wallacean doctrine of the
+origin of all specific characters by means of natural selection was
+propounded many years before either Galton or Weismann had questioned
+the transmission of acquired characters. However. I allow that this line
+of argument has now become--for the time being at all events--a dubious
+line, and will therefore at once pass on to the second line, which is
+not open to doubt from any quarter.
+
+Whether or not we accept Weismann's views, it will here be convenient to
+employ his terminology, since this will serve to convey the somewhat
+important distinctions which it is now my object to express.
+
+In the foregoing paragraphs, under heading (A), we have seen that there
+must be "literally numberless forms" which have been ranked as true
+species, whose diagnostic characters are nevertheless not congenital. In
+the case of plants especially, we know that there must be large numbers
+of named species which do not conform to the criterion of Heredity,
+although we do not know which species they are. For present purposes,
+however, it is enough for us to know that there are many such named
+species, where some change of environment has acted directly and
+similarly on all the individual "somas" exposed to it, without affecting
+their "germ-plasms," or the material bases of their hereditary
+qualities. For named species of this kind we may employ the term
+_somatogenetic species_.
+
+But now, if there are any cases where a change of environment does act
+on the germ-plasms exposed to it, the result would be what we may call
+_blastogenetic species_--i.e. species which conform to the criterion of
+Heredity, and would therefore be ranked by all naturalists as "true
+species." It would not signify in such a case whether the changed
+conditions of life first affected the soma, and then, through changed
+nutrition, the germ-plasm; or whether from the first it directly
+affected the germ-plasm itself. For in either case the result would be a
+"species," which would continue to reproduce its peculiar features by
+heredity.
+
+Now, the supposition that changed conditions of life may thus affect the
+congenital endowments of germ-plasm is not a gratuitous one. The sundry
+facts already given in previous chapters are enough to show that the
+origin of a blastogenetic species by the direct action on germ-plasm of
+changed conditions of life is, at all events, a possibility. And a
+little further thought is enough to show that this possibility becomes a
+probability--if not a virtual certainty. Even Weismann--notwithstanding
+his desire to maintain, as far as he possibly can, the "stability" of
+germ-plasm--is obliged to allow that external conditions acting on the
+organism may in some cases modify the hereditary qualities of its
+germ-plasm, and so, as he says, "determine the phyletic development of
+its descendants." Again, we have seen that he is compelled to interpret
+the results of his own experiments on the climatic varieties of certain
+butterflies by saying, "I cannot explain the facts otherwise than by
+supposing the passive acquisition of characters produced by direct
+influences of climate"; by which he means that in this case the
+influence of climate acts directly on the hereditary qualities of
+germ-plasm. Lastly, and more generally, he says:--
+
+     "But although I hold it improbable that individual variability can
+     depend on a direct action of external influences upon the
+     germ-cells and their contained germ-plasm, because--as follows from
+     sundry facts--the molecular structure of the germ-plasm must be
+     very difficult to change, yet it is by no means to be implied that
+     this structure may not possibly be altered by influences of the
+     same kind continuing for a very long time. Thus it seems to me the
+     possibility is not to be rejected, that influences continued for a
+     long time, that is, for generations, such as temperature, kind of
+     nourishment, &c., which may affect the germ-cells as well as any
+     other part of the organism, may produce a change in the
+     constitution of the germ-plasm. But such influences would not then
+     produce individual variation, but would necessarily modify in the
+     same way all the individuals of a species living in a certain
+     district. It is possible, though it cannot be proved, that many
+     climatic varieties have arisen in this manner."
+
+So far, then, we have testimony to this point, as it were, from a
+reluctant witness. But if we have no theory involving the "stability of
+germ-plasm" to maintain, we can scarcely fail to see how susceptible the
+germ-plasm is likely to prove to changed conditions of life. For we know
+how eminently susceptible it is in this respect when gauged by the
+practical test of fertility; and as this is but an expression of its
+extraordinarily complex character, it would indeed be surprising if it
+were to enjoy any immunity against modification by changed conditions of
+life. We have seen in the foregoing chapter how frequently and how
+considerably somatogenetic changes are thus caused, so as to produce
+"somatogenetic species"--or, where we happen to know that the changes
+are not hereditary, "climatic varieties." But the constitution of
+germ-plasm is much more complex than that of any of the structures which
+are developed therefrom. Consequently, the only wonder is that hitherto
+experimentalists have not been more successful in producing
+"blastogenetic species" by artificial changes of environment. Or, as Ray
+Lankester has well stated this consideration, "It is not difficult to
+suggest possible ways in which the changed conditions, shown to be
+important by Darwin, could act through the parental body upon the
+nuclear matter of the egg-cell and sperm-cell, with its immensely
+complex and therefore unstable constitution.... The wonder is, not that
+[blastogenetic] variation occurs, but that it is not excessive and
+monstrous in every product of fertilization[124]."
+
+    [124] _Nature_, Dec. 12, 1889, p. 129.
+
+If to this it should be objected that, as a matter of fact,
+experimentalists have not been nearly so successful in producing
+congenital modifications of type by changed conditions of life as they
+have been in thus producing merely somatic modifications; or if it
+should be further objected that we have no evidence at all in nature of
+a "blastogenetic species" having been formed by means of climatic
+influences alone,--if these objections were to be raised, they would
+admit of the following answer.
+
+With regard to experiments, so few have thus far been made upon the
+subject, that objections founded on their negative results do not carry
+much weight--especially when we remember that these results have not
+been uniformly negative, but sometimes positive, as shown in Chapter VI.
+With regard to plants and animals in a state of nature, the objection is
+wholly futile, for the simple reason that in as many cases as changed
+conditions of life may have caused an hereditary change of specific
+type, there is now no means of obtaining "evidence" upon the subject.
+But we are not on this account entitled to conclude against the
+probability of such changes of specific type having been more or less
+frequently thus produced. And still less can we be on this account
+entitled to conclude against the _possibility_ of such a change having
+ever occurred in any single instance. Yet this is what must be concluded
+by any one who maintains that the origin of all species--and, _a
+fortiori_, of all specific characters--must _necessarily_ have been due
+to natural selection.
+
+Now, if all this be admitted--and I do not see how it can be reasonably
+questioned--consider how important its bearing becomes on the issue
+before us. If germ-plasm (using this term for whatever it is that
+constitutes the material basis of heredity) is ever capable of having
+its congenital endowments altered by the direct action of external
+conditions, the resulting change of hereditary characters, whatever else
+it may be, need not be an adaptive change. Indeed, according to
+Weismann's theory of germ-plasm, the chances must be infinitely against
+the change being an adaptive one. On the theory of pangenesis--that is
+to say, on the so-called Lamarckian principles--there would be much more
+reason for entertaining the possibly adaptive character of hereditary
+change due to the direct action of the environment. Therefore we arrive
+at this curious result. The more that we are disposed to accept
+Weismann's theory of heredity, and with it the corollary that natural
+selection is the sole cause of adaptive modification in species the less
+are we entitled to assume that all specific characters must necessarily
+be adaptive. Seeing that in nature there are presumably many cases like
+those of Hoffmann's plants, Weismann's butterflies, &c., where the
+hereditary qualities of germ-plasm have (on his hypothesis) been
+modified by changed conditions of life, we are bound to believe that, in
+all cases where such changes do not happen to be actively deleterious,
+they will persist. And inasmuch as characters which are only of
+"specific" value must be the characters most easily--and therefore most
+frequently--induced by any slight changes in the constitution of
+germ-plasm, while, for the same reason (namely, that of their trivial
+nature) they are least likely to prove injurious, it follows that the
+less we believe in the functionally-produced adaptations of Lamarck, the
+more ought we to resist the assumption that all specific characters must
+necessarily be adaptive characters.
+
+       *       *       *       *       *
+
+Upon the whole, then, and with regard to the direct action of external
+conditions, I conclude--not only from general considerations, but also
+from special facts or instances quite sufficient for the purpose--that
+these must certainly give rise to immense numbers of somatogenetic
+species on the one hand, and probably to considerable numbers of
+blastogenetic species on the other; that in neither case is there any
+reason for supposing the distinctively "specific characters" to be other
+than "neutral" or "indifferent"; while there are the best of reasons for
+concluding the contrary. So that, under this division of our subject
+alone (B), there appears to be ample justification for the statement
+that "a large proportional number of specific characters" are in
+reality, as they are in appearance, destitute of significance from a
+utilitarian point of view.
+
+
+(C.)
+
+Thus far in the present chapter we have been dealing exclusively with
+the case of "climatic variation," or change of specific type due to
+changes in the external conditions of life. But it will be remembered
+that, in the preceding chapter, allusion was likewise made to changes of
+specific type due to internal causes, or to what Darwin has called "the
+nature of the organism." Under this division of our subject I mentioned
+especially Sexual Selection, which is supposed to arise in the aesthetic
+taste of animals themselves; Isolation, which is supposed to originate
+new types by allowing the average characters of an isolated section of
+an old type to develop a new history of varietal change, as we shall see
+more fully in the ensuing part of this treatise; and the Laws of Growth,
+which is a general term for the operation of unknown causes of change
+incidental to the living processes of organisms which present the
+change.
+
+Now, under none of these divisions of our subject can there be any
+question touching the criterion of Heredity. For if new species--or even
+single specific characters of new species--are ever produced by any of
+these causes, they must certainly all "reproduce their like." Therefore
+the only question which can here obtain is as to whether or not such
+causes ever do originate new species, or even so much as new specific
+characters. Mr. Wallace, though not always consistently, answers this
+question in the negative; but the great majority of naturalists follow
+Darwin by answering it in the affirmative. And this is enough to show
+the only point which we need at present concern ourselves with
+showing--viz. that the question is, at the least, an open one. For as
+long as this question is an open one among believers in the theory of
+natural selection, it must clearly be an unwarrantable deduction from
+that theory, that all species, and _a fortiori_ all specific characters,
+are necessarily due to natural selection. The deduction cannot be
+legitimately drawn until the possibility of any other cause of specific
+modification has been excluded. But the bare fact of the question as
+just stated being still and at the least an open question, is enough to
+prove that this possibility has not been excluded. Therefore the
+deduction must be, again on this ground alone (C), unwarrantable.
+
+       *       *       *       *       *
+
+Such are my several reasons--and it is to be observed that they are all
+_independent_ reasons--for concluding that it makes no practical
+difference to the present discussion whether or not we entertain
+Heredity as a criterion of specific distinction. Seeing that our
+species-makers have paid so little regard to this criterion, it is
+neither absurd nor preposterous to have adduced, in the preceding
+chapter, the facts of climatic variation. On the contrary, as the
+definition of "species" which has been practically followed by our
+species-makers in No. 3, and not No. 4, these facts form part and parcel
+of our subject. It is perfectly certain that, in the vegetable kingdom
+at all events, "a large proportional number" of specifically diagnostic
+characters would be proved by experiment to be "somatogenetic"; while
+there are numerous constant characters classed as varietal, although it
+is well known that they are "blastogenetic." Moreover, we can scarcely
+doubt that many specific characters which are also hereditary characters
+owe their existence, not to natural selection, but to the direct action
+of external causes on the hereditary structure of "germ-plasm"; while,
+even apart from this consideration, there are at least three distinct
+and highly general principles of specific change, which are accepted by
+the great majority of Darwinists, and the only common peculiarity of
+which is that they produce hereditary changes of specific types without
+any reference to the principle of utility.
+
+
+
+
+CHAPTER X.
+
+CHARACTERS AS ADAPTIVE AND SPECIFIC
+(_concluded_).
+
+
+Our subject is not yet exhausted. For it remains to observe the
+consequences which arise from the dogma of utility as the only _raison
+d'etre_ of species, or of specific characters, when this dogma is
+applied in practice by its own promoters.
+
+       *       *       *       *       *
+
+Any definition of "species"--excepting Nos. 1, 2, and 5, which may here
+be disregarded--must needs contain some such phrase as the one with
+which Nos. 3 and 4 conclude. This is, that peculiar characters, in order
+to be recognized as of specific value, must present neither more nor
+less than "some certain degree of distinctness." If they present more
+than this degree of distinctness, the form, or forms, in question must
+be ranked as generic; while if they present less than this degree of
+distinctness, they must be regarded as varietal--and this even if they
+are known to be mutually sterile. What, then, is this certain degree of
+distinctness? What are its upper and lower limits? This question is one
+that cannot be answered. From the very nature of the case it is
+impossible to find a uniform standard of distinction whereby to draw
+our boundary lines between varieties and species on the one hand, or
+between species and genera on the other. One or two quotations will be
+sufficient to satisfy the general reader upon this point.
+
+Mr. Wallace himself alludes to "the great difficulty that is felt by
+botanists in determining the limits of species in many large genera,"
+and gives as examples well-known instances where systematic botanists of
+the highest eminence differ hopelessly in their respective estimates of
+"specific characters." Thus:--
+
+     "Mr. Baker includes under a single species, Rosa canina, no less
+     than twenty-eight named varieties distinguished by more or less
+     constant characters, and often confined to special localities, and
+     to these are referred about seventy of the species of British and
+     continental botanists. Of the genus Rubus or bramble, five British
+     species are given in Bentham's _Handbook of British Flora_, while
+     in the fifth edition of Babington's _Manual of British Botany_,
+     published about the same time, no less than forty-five species are
+     described. Of willows (Salix) the same two works enumerate fifteen
+     and thirty-one species respectively. The hawkweeds (Hieracium) are
+     equally puzzling, for while Mr. Bentham admits only seven British
+     species, Professor Babington describes no less than seventy-two,
+     besides several named varieties[125]."
+
+    [125] _Darwinism_, p. 77.
+
+Mr. Wallace goes on to quote further instances, such as that of Draba
+verna, which Jordan has found to present, in the south of France alone,
+no less than fifty-two permanent varieties, which all "come true from
+seed, and thus present all the characteristics of a true species"; so
+that, "as the plant is very common almost all over Europe, and ranges
+from North America to the Himalayas, the number of similar forms over
+this wide area would probably have to be reckoned by hundreds, if not by
+thousands[126]."
+
+    [126] _Darwinism_, p. 77.
+
+One or two further quotations may be given to the same general effect,
+selected from the writings of specialists in their several departments.
+
+     "There is nothing that divides systematists more than what
+     constitutes a genus. Species that resemble each other more than
+     other species, is perhaps the best definition that can be given.
+     This is obviously an uncertain test, much depending on individual
+     judgement and experience; but that, in the evolution of forms, such
+     difficulties should arise in the limitation of genera and species
+     was inevitable. What is a generic character in one may be only a
+     specific character in another. As an illustration of the uncertain
+     importance of characters, I may mention the weevil genus
+     _Centrinus_ in which the leading characters in the classification
+     of the family to which it belongs are so mixed that systematists
+     have been content to keep the species together in a group that
+     cannot be defined.... No advantage or disadvantage is attached,
+     apparently, to any of the characters. There are about 200 species,
+     all American.
+
+     The venation of the wings of insects is another example of
+     modifications without serving any special purpose. There is no vein
+     in certain Thripidae, and only a rudiment or a single vein in
+     Chalcididae. There are thousands of variations more or less marked,
+     some of the same type with comparatively trivial variation, others
+     presenting distinct types, even in the same family, such genera,
+     for example, as _Polyneura_, _Tettigetra_, _Huechys_, &c. in the
+     Cicadidae.
+
+     Individual differences have often been regarded as distinctive of
+     species; varieties also are very deceptive, and races come very
+     near to species. A South-American beetle, _Arescus histrio_, has
+     varieties of yellow, red, and black, or these colours variously
+     intermixed, and, what is very unusual, longitudinal stripes in some
+     and transverse bars in others, and all taken in the same locality.
+     Mr. A. G. Butler, of the British Museum, is of opinion that 'what
+     is generally understood by the term species (that is to say, a
+     well-defined, distinct, and constant type, having no near allies)
+     is non-existent in the Lepidoptera, and that the nearest approach
+     to it in this order is a constant, though but slightly differing,
+     rare or local form--that genera, in fact, consist wholly of a
+     gradational series of such forms (Ann. Mag. Nat. Hist. 5, xix.
+     103)[127].'"
+
+    [127] Pascoe, _The Darwinian Theory of the Origin of Species_, 1891,
+          pp. 31-33, and 46.
+
+So much as regards entomology, and still living forms. In illustration
+of the same principles in connexion with palaeontological series, I may
+quote Wuertenberger, who says:--
+
+     "With respect to these fossil forms [i.e. multitudinous forms of
+     fossil Ammonites], it is quite immaterial whether a very short or a
+     somewhat longer part of any branch be dignified with a separate
+     name, and regarded as a species. The prickly Ammonites, classed
+     under the designation of Armata, are so intimately connected that
+     it becomes impossible to separate the accepted species sharply from
+     one another. The same remark applies to the group of which the
+     manifold forms are distinguished by their ribbed shells, and are
+     called Planulata[128]."
+
+    [128] _Neuer Beitrag zum geologischen Beweis der Darwinischen
+          Theorie_, 1873.
+
+I had here supplied a number of similar quotations from writers in
+various other departments of systematic work, but afterwards struck them
+out as superfluous. For it is not to be anticipated that any competent
+naturalist will nowadays dispute that the terms "variety," "species,"
+and "genus" stand for merely conventional divisions, and that whether a
+given form shall be ranked under one or the other of them is often no
+more than a matter of individual taste. From the nature of the case
+there can be no objective, and therefore no common, standards of
+delimitation. This is true even as regards any one given department of
+systematic work; but when we compare the standards of delimitation which
+prevail in one department with those which prevail in another, it
+becomes evident that there is not so much as any attempt at agreeing
+upon a common measure of specific distinction.
+
+But what, it may well be asked, is the use of thus insisting upon
+well-known facts, which nobody will dispute? Well, in the first place,
+we have already seen, in the last chapter, that it is incumbent on those
+who maintain that all species, or even all specific characters, must be
+due to natural selection, to tell us what they mean by a species, or by
+characters as specific. If I am told to believe that the definite
+quality A is a necessary attribute of B, and yet that B is "not a
+distinct entity," but an undefinable abstraction, I can only marvel that
+any one should expect me to be so simple. But, without recurring to this
+point, the use of insisting on the facts above stated is, in the second
+place, that otherwise I cannot suppose any general reader could believe
+them in view of what is to follow. For he cannot but feel that the cost
+of believing them is to render inexplicable the mental processes of
+those naturalists who, in the face of such facts, have deduced the
+following conclusions.
+
+The school of naturalists against which I am contending maintains, as a
+generalization deduced from the theory of natural selection, that all
+species, or even all specific characters, must necessarily owe their
+origin to the principle of utility. Yet this same school does not
+maintain any such generalization, either with regard to varietal
+characters on the one hand, or to generic characters on the other. On
+the contrary, Professor Huxley, Mr. Wallace, and all other naturalists
+who agree with them in refusing to entertain so much as the abstract
+possibility of any cause other than natural selection having been
+productive of species, fully accept the fact of other causes having been
+largely concerned in the production of varieties, genera, families, and
+all higher groups, or of the characters severally distinctive of each.
+Indeed, Mr. Wallace does not question what appears to me the extravagant
+estimate of Professor Cope, that the non-adaptive characters distinctive
+of those higher groups are fully equal, in point of numbers, to the
+adaptive. But, surely, if the theory of evolution by natural selection
+is, as we all agree, a true theory of the origin of species, it must
+likewise be a true theory of the origin of genera; and if it be supposed
+essential to the integrity of the theory in its former aspect that all
+specific characters should be held to be useful, I fail to see how, in
+regard to its latter aspect, we are so readily to surrender the
+necessary usefulness of all generic characters. And exactly the same
+remark applies to the case of constant "varieties," where again the
+doctrine of utility as universal is not maintained. Yet, according to
+the general theory of evolution, constant varieties are what Darwin
+termed "incipient species," while species are what may be termed
+"incipient genera." Therefore, if the doctrine of utility as universal
+be conceded to fail in the case of varieties on the one hand and of
+genera on the other, where is the consistency in maintaining that it
+must "necessarily" hold as regards the intermediate division, species?
+Truly the shade of Darwin may exclaim, "Save me from my friends." And
+truly against logic of this description a follower of Darwin must find
+it difficult to argue. If one's opponents were believers in special
+creation, and therefore stood upon some definite ground while
+maintaining this difference between species and all other taxonomic
+divisions, there would at least be some issue to argue about. But when
+on the one hand it is conceded that species are merely arbitrary
+divisions, which differ in no respect as to the process of their
+evolution from either varieties or genera, while on the other hand it is
+affirmed that there is thus so great a difference in the result, all we
+can say is that our opponents are entangling themselves in the meshes of
+a sheer contradiction.
+
+Or, otherwise stated, specific characters differ from varietal
+characters in being, as a rule, more pronounced and more constant: on
+this account advocates of utility as universal apply the doctrine to
+species, while they do not feel the "necessity" of applying it to
+varieties. But now, generic and all higher characters are even more
+constant and more pronounced than specific characters--not to say, in
+many cases, more generally diffused over a larger number of organisms
+usually occupying larger areas. Therefore, _a fortiori_, if for the
+reasons above stated evolutionists regard it as a necessary deduction
+from the theory of natural selection that all specific characters must
+be useful, much more ought it to be a necessary deduction from this
+theory that all generic, and still more all higher, characters must be
+useful. But, as we have seen, this is not maintained by our opponents.
+On the contrary, they draw the sharpest distinction between specific and
+all other characters in this respect, freely conceding that both those
+below and those above them need not--and very often do not--present any
+utilitarian significance.
+
+Although it appears to me that this doctrine is self-contradictory, and
+on this ground alone might be summarily dismissed, as it is now held in
+one or other of its forms by many naturalists, I will give it a more
+detailed consideration in both its parts--namely, first with respect to
+the distinction between varieties and species, and next with respect to
+the distinction between species and genera.
+
+       *       *       *       *       *
+
+Until it can be shown that species are something more than merely
+arbitrary divisions, due to the disappearance of intermediate varietal
+links; that in some way or another they _are_ "definite entities," which
+admit of being delineated by the application of some uniform or general
+principles of definition; that, in short, species have only then been
+classified as such when it has been shown that the origin of each has
+been due to the operation of causes which have not been concerned in the
+production of varieties;--until these things are shown, it clearly
+remains a gratuitous dogma to maintain that forms which have been called
+species differ from forms which have been called varieties in the
+important respect, that they (let alone each of all their distinctive
+characters) must necessarily have been due to the principle of utility.
+Yet, as we have seen, even Mr. Wallace allows that a species is "not a
+distinct entity," but "an assemblage of individuals which have become
+somewhat modified in structure, form, and constitution"; while estimates
+of the kinds and degrees of modification which are to be taken as of
+specific value are conceded to be undefinable, fluctuating, and in not a
+few cases almost ludicrously divergent.
+
+Perhaps one cannot more forcibly present the rational value of this
+position than by noting the following consequences of it. Mr. Gulick
+writes me that while studying the land-shells of the Sandwich Islands,
+and finding there a rich profusion of unique varieties, in cases where
+the intermediate varieties were rare he could himself have created a
+number of species by simply throwing these intermediate varieties into
+his fire. Now it follows from the dogma which we are considering, that,
+by so doing, not only would he have created new species, but at the same
+time he would have proved them due to natural selection, and endowed the
+diagnostic characters of each with a "necessarily" adaptive meaning,
+which previously it was not necessary that they should present. Before
+his destruction of these intermediate varieties, he need have felt
+himself under no obligation to assume that any given character at either
+end of the series was of utilitarian significance: but, after his
+destruction of the intermediate forms, he could no longer entertain any
+question upon the matter, under pain of being denounced as a Darwinian
+heretic.
+
+Now the application is self-evident. It is a general fact, which admits
+of no denial, that the more our knowledge of any flora or fauna
+increases, the greater is the number of intermediate forms which are
+brought to light, either as still existing or as having once existed.
+Consequently, the more that such knowledge increases, the more does our
+catalogue of "species" diminish. As Kerner says, "bad species" are
+always multiplying at the expense of "good species"; or, as Oscar
+Schmidt (following Haeckel) similarly remarks, if we could know as much
+about the latter as we do about the former, "all species, without any
+exception, would become what species-makers understand by 'bad
+species'[129]." Hence we see that, just as Mr. Gulick could have created
+good species by secretly destroying his intermediate varieties, so has
+Nature produced her "good species" for the delectation of systematists.
+And just as Mr. Gulick, by first hiding and afterwards revealing his
+intermediate forms, could have made the self-same characters in the
+first instance necessarily useful, but ever afterwards presumably
+useless, so has Nature caused the utility of diagnostic characters to
+vary with our knowledge of her intermediate forms. It belongs to the
+essence of our theory of descent, that in _all_ cases these intermediate
+forms must either be now existing or have once existed; and, therefore,
+that the work of species-makers consists in nothing more than marking
+out the _lacunae_ in our knowledge of them. Yet we are bound to believe
+that wherever these _lacunae_ in our knowledge occur, there occurs also
+the objective necessity of causation as utilitarian--a necessity,
+however, which vanishes so soon as our advancing information supplies
+the intermediate forms in question. It may indeed appear strange that
+the utility or non-utility of organic structures should thus depend on
+the accidents of human knowledge; but this is the Darwinian faith, and
+he who doubts the dogma is to be anathema.
+
+    [129] _The Doctrine of Descent and Darwinism_, Eng. Trans. p. 102.
+
+Turning next to the similar distinction which it is sought to draw
+between species and genera, here it will probably be urged, as I
+understand it to be urged by Mr. Wallace, that generic characters (and
+still more characters of families, orders, &c.) refer back to so remote
+a state of things that utility may have been present at their birth
+which has disappeared in their maturity. In other words, it is held that
+all generic characters were originally specific characters; that as such
+they were all originally of use; but that, after having been rendered
+stable by heredity, many of them may have ceased to be of service to the
+descendants of those species in which they originated, and whose
+extinction has now made it impossible to divine what that service may
+have been.
+
+Now, in the first place; this is not the interpretation adopted by
+Darwin. For instance, he expressly contrasts such cases with those of
+vestigial or "rudimentary" structures, pointing out that they differ
+from vestigial structures in respect of their permanence. One quotation
+will be sufficient to establish the present point.
+
+     "A structure which has been developed through long-continued
+     selection, when it ceases to be of service to a species, generally
+     becomes variable, as we see with rudimentary organs, for it will no
+     longer be regulated by this same power of selection. But when, from
+     the nature of the organism and of the conditions, modifications
+     have been induced which are unimportant for the welfare of the
+     species, they may be, and apparently often have been, transmitted
+     in nearly the same state to numerous, otherwise modified,
+     descendants[130]."
+
+    [130] _Origin of Species_, p. 175.
+
+Here, and in the context, we have a sufficiently clear statement of
+Darwin's view--first, that unadaptive characters may arise in _species_
+as "fluctuating variations, which sooner or later become _constant_
+through the nature of the organism and of surrounding conditions, as
+well as through the intercrossing of distinct individuals, but _not_
+through natural selection"[131]; second, that such unadaptive characters
+may then be transmitted in this their stable condition to
+species-progeny, so as to become distinctive of genera, families, &c.;
+third, that, on account of such characters not being afterwards liable
+to diverse adaptive modifications in different branches of the
+species-progeny, they are of more value as indicating lines of pedigree
+than are characters which from the first have been useful; and, lastly,
+they are therefore now empirically recognized by systematists as of most
+value in guiding the work of classification. To me it appears that this
+view is not only perfectly rational in itself, but likewise fully
+compatible with the theory of natural selection--which, as I have
+previously shown, is _primarily_ a theory of adaptive characters, and
+therefore not necessarily a theory of _all_ specific characters. But to
+those who think otherwise, it must appear--and does appear--that there
+is something wrong about such a view of the case--that it was not
+consistent in the author of the _Origin of Species_ thus to refer
+non-adaptive generic characters to a parentage of non-adaptive specific
+characters. Nevertheless, as a matter of fact, Darwin was perfectly
+consistent in putting forth this view, because, unlike Wallace, he was
+not under the sway of any antecedent dogma erroneously deduced from the
+theory of natural selection.
+
+    [131] _Ibid._ p. 176: italics mine.
+
+Next without reference to Darwin's authority, let us see for ourselves
+where the inconsistency really lies. To allow that generic characters
+may be useless, while denying that specific characters can ever be so
+(unless correlated with others that are useful), involves an appeal to
+the argument from ignorance touching the ancestral habits,
+life-conditions, &c., of a parent species now extinct. Well, even upon
+this assumption of utility as obsolete, there remains to be explained
+the "stability" of useless characters now distinctive of genera,
+families, orders, and the rest. We know that specific characters which
+have owed their origin to utility and have afterwards ceased to present
+utility, degenerate, become variable, inconstant, "rudimentary," and
+finally disappear. Why, then, should these things not happen with regard
+to useless generic distinctions? Still more, why should they not happen
+with regard to family, ordinal, and class distinctions? On the lines
+against which I am arguing it would appear impossible that any answer to
+this question can be suggested. For what explanation can be given of the
+contrast thus presented between the obsolescence of specific characters
+where previous utility is demonstrable, and the permanence of higher
+characters whose previous utility is assumed? As we have already seen,
+Mr. Wallace himself employs this consideration of permanence and
+constancy against the view that any cause other than natural selection
+can have been concerned in the origin and maintenance of _specific_
+characters. But he does not seem to see that the consideration cuts two
+ways--and much more forcibly against his views than in favour of them.
+For while, as already shown in the chapter before last, it is
+sufficiently easy to dispose of the consideration as Wallace uses it (by
+simply pointing out with Darwin that any causes other than natural
+selection which may have been concerned in the genesis of _specific_
+characters, must, if equally uniform in their operation, equally give
+rise to permanence and constancy in their results); on the other hand,
+it becomes impossible to explain the stability of useless _generic_
+characters, if, as Wallace's use of the argument requires, natural
+selection is the only possible cause of stability. The argument is one
+that cannot be played with fast and loose. Either utility is the sole
+condition to the stability of _any_ diagnostic character (in which case
+it is not open to Mr. Wallace to assume that all _generic_ or higher
+characters which are now useless have owed their origin to a past
+utility); or else utility is not the sole condition to stability (in
+which case his use of the present argument in relation to _specific_
+characters collapses). We have seen, indeed, in the chapter before last,
+that his use of the argument collapses anyhow, or quite irrespective of
+his inconsistent attitude towards generic characters, with which we were
+not then concerned. But the point now is that, as a mere matter of
+logic, the argument from stability as Wallace applies it to the case of
+specific characters, is incompatible with his argument that useless
+generic characters may originally have been useful specific characters.
+It can scarcely be questioned that the transmutation of a species into a
+genus must, as a rule, have allowed time enough for a newly
+acquired--i.e. peculiar specific-character--to show some signs of
+undergoing degeneration, if, as supposed, the original cause of its
+development and maintenance was withdrawn when the parent species began
+to ramify into its species-progeny. Yet, as Darwin says, "it is
+notorious that specific characters are more variable than generic[132]."
+So that, upon the whole, I do not see how on grounds of general
+reasoning it is logically possible to maintain Mr. Wallace's distinction
+between specific and generic characters in respect of necessary utility.
+
+    [132] _Origin of Species_, p. 122.
+
+But now, and lastly, we shall reach the same conclusion if, discarding
+all consideration of general principles and formal reasoning, we fasten
+attention upon certain particular cases, or concrete facts. Thus, to
+select only two illustrations within the limits of genera, it is a
+diagnostic feature of the genus _Equus_ that small warty callosities
+occur on the legs. It is impossible to suggest any useful function that
+is now discharged by these callosities in any of the existing species of
+the genus. If it be assumed that they must have been of some use to the
+species from which the genus originally sprang, the assumption, it seems
+to me, can only be saved by further assuming that in existing species of
+the genus these callosities are in a vestigial condition--i. e. that in
+the original or parent species they performed some function which is
+now obsolete. But against these assumptions there lies the following
+fact. The callosities in question are not similarly distributed through
+all existing species of the genus. The horse has them upon all his four
+legs, while other species have them only upon two. Therefore, if all
+specific characters are necessarily due to natural selection, it is
+manifest that these callosities are _not_ now vestigial: on the
+contrary, they _must_ still be--or, at best, have recently been--of so
+much importance to all existing species of the genus, that not only is
+it a matter of selection-value to all these species that they should
+possess these callosities; but it is even a matter of selection-value to
+a horse that he should possess four of them, while it is equally a
+matter of selection-value to the ass that he should possess only two.
+Here, it seems to me, we have once more the doctrine of the necessary
+utility of specific characters reduced to an absurdity; while at the
+same time we display the incoherency of the distinction between specific
+characters and generic characters in respect of this doctrine. For the
+distinction in such a case amounts to saying that a generic character,
+if evenly distributed among all the species, need not be an adaptive
+character; whereas, if any one of the species presents it in a slightly
+different form, the character must be, on this account, necessarily
+adaptive. In other words, the uniformity with which a generic character
+occurs among the species of the genus is taken to remove that character
+from the necessarily useful class, while the absence of such uniformity
+is taken as proof that the character must be placed within the
+necessarily useful class. Which is surely no less a _reductio ad
+absurdum_ with regard to the generic character than the one just
+presented with regard to its variants as specific characters. And, of
+course, this twofold absurdity is presented in all cases where a generic
+character is unequally distributed among the constituent species of a
+genus.
+
+[Illustration: Fig. 4.--Lower Teeth of Orang (after Tomes).]
+
+But here is an illustration of another class of cases. Mr. Tomes has
+shown that the molar teeth of the Orang present an extraordinary and
+altogether superfluous amount of attachment in their sockets--the fangs
+being not only exceedingly long, and therefore deeply buried in the
+jaw-bone, but also curving round one another, so as still further to
+strengthen the whole[133]. In the allied genera of anthropoid apes there
+is no such abnormal amount of attachment. Now, the question is, of what
+conceivable use can it _ever_ have been, either to the existing genus,
+or to its parent species, that such an abnormal amount of attachment
+should obtain? It certainly is not required to prevent dislocation of
+the teeth, seeing that in all allied genera, and even in man himself,
+the amount of attachment is already so great that teeth will break
+before they can be drawn by anything short of a dentist's forceps.
+Therefore I conclude that this peculiarity in the dentition of the genus
+must have arisen in its parent species by way of what Darwin calls a
+"fluctuating variation," without utilitarian significance. And I adduce
+it in the present connexion because the peculiarity is one which is
+equally unamenable to a utilitarian explanation, whether it happens to
+occur as a generic or a specific character.
+
+    [133] _A Manual of Dental Anatomy_, p. 455.
+
+Numberless similar cases might be quoted; but probably enough has now
+been said to prove the inconsistency of the distinction which our
+opponents draw between specific and all higher characters in respect of
+utility. In point of fact, a very little thought is enough to show that
+no such distinction admits of being drawn; and, therefore, that any one
+who maintains the doctrine of utility as universal in the case of
+specific characters, must in consistency hold to the same doctrine in
+the case of generic and all higher characters. And the fact that our
+opponents are unable to do this becomes a virtual confession on their
+part of the futility of the generalization which they have
+propounded[134].
+
+    [134] It may be observed that this distinction was not propounded by
+          Mr. Wallace--nor, so far as I am aware, by anybody else--until
+          he joined issue with me on the subject of specific characters.
+          Whether he has always held this important distinction between
+          specific and generic characters, I know not; but, as
+          originally enunciated, his doctrine of utility as universal
+          was subject to no such limitation: it was stated
+          unconditionally, as applying to all taxonomic divisions
+          indifferently. The words have already been quoted on page 180;
+          and, if the reader will turn to them, he may further observe
+          that, prior to our discussion, Mr. Wallace made no allowance
+          for the principle of correlation, which, as we have seen,
+          furnishes so convenient a loop-hole of escape in cases where
+          even the argument from our ignorance of possible utility
+          appears absurd. In his latest work, however, he is much less
+          sweeping in his statements. He limits his doctrine to the case
+          of "specific characters" alone, and even with regard to them
+          makes unlimited drafts upon the principle of correlation.
+
+On what then do Mr. Wallace and his followers rely for their great
+distinction between specific and all other characters in respect of
+utility? This is the final and fundamental question which I must leave
+these naturalists themselves to answer; for my whole contention is, that
+it is unanswerable. But although I am satisfied that they have nothing
+on which to base their generalization, it seems worth while to conclude
+by showing yet one further point. And this is, that these naturalists
+themselves, as soon as they quit merely abstract assertions and come to
+deal with actual facts, contradict their own generalization. It is worth
+while to show this by means of a few quotations, that we may perceive
+how impossible it is for them to sustain their generalization in the
+domain of fact.
+
+As it is desirable to be brief, I will confine myself to quoting from
+Mr. Wallace.
+
+     "Colour may be looked upon as a necessary result of the highly
+     complex chemical constitution of animal tissues and fluids. The
+     blood, the bile, the bones, the fat, and other tissues have
+     characteristic, and often brilliant colours, which we cannot
+     suppose to have been determined for any special purpose as colours,
+     since they are usually concealed. The external organs and
+     integuments, would, by the same general laws, naturally give rise
+     to a greater variety of colour[135]."
+
+    [135] _Darwinism_, p. 297.
+
+Surely comment is needless. Have the colour of external organs and
+integuments nothing to do with the determining of specific distinctions
+by systematists? Or, may we not rather ask, are there any other
+"characters" which have had more to do with their delineation of animal
+species? Therefore, if "the external organs and integuments naturally
+give rise to a greater variety of colours," for non-utilitarian reasons,
+than is the case with internal organs and tissues; while even the latter
+present, for similarly non-utilitarian reasons, such variety and
+intensity of colours as they do; must it not follow that, on the ground
+of the "Laws of Growth" alone, Mr. Wallace has conceded the entire case
+as regards "a large proportional number of specific characters" being
+non-adaptive--"spontaneous" in their occurrence, and "meaningless" in
+their persistence?
+
+Once more:--
+
+     "The enormously lengthened plumes of the bird of paradise and of
+     the peacock, can, however, have no such use [i.e. for purposes of
+     defence], but must be rather injurious than beneficial in the
+     birds' ordinary life. The fact that they have been developed to so
+     great an extent in a few species is an indication of such perfect
+     adaptation to the conditions of existence, such complete success in
+     the battle for life, that there is, in the adult male at all
+     events, a surplus of strength, vitality, and growth-power, which is
+     able to expend itself in this way without injury. That such is the
+     case is shown by the great abundance of most of the species which
+     possess these wonderful superfluities of plumage.... Why, in allied
+     species, the development of accessory plumes has taken different
+     forms, we are unable to say, except that it may be due to that
+     individual variability which has served as a starting-point for so
+     much of what seems to us strange in form, or fantastic in colour,
+     both in the animal and vegetable world[136]."
+
+    [136] _Darwinism_, pp. 292-3.
+
+Here, again, one need only ask, How can such statements be reconciled
+with the great dogma, "which is indeed a necessary deduction from the
+theory of Natural Selection, namely, that none of the definite facts of
+organic nature, no special organ, no characteristic form or marking can
+exist, but which must now be, or once have been, _useful_"? Can it be
+said that the plumes of a bird of paradise present "no characteristic
+form," or the tail of a peacock "no characteristic marking"? Can it be
+held that all the "fantastic colours," which Darwin attributes to sexual
+selection, and all the "strange forms" in the vegetable world which
+present no conceivable reference to adaptation, are to be ascribed to
+"individual variability" without reference to utility, while at the same
+time it is held, "as a necessary deduction from the theory of Natural
+Selection," that _all_ specific characters must be "_useful_"? Or must
+we not conclude that we have here a contradiction as direct as a
+contradiction can well be[137]?
+
+    [137] Since the above was written both Mr. Gulick and Professor
+          Lloyd Morgan have independently noticed the contradiction.
+
+Nor is it any more possible to reconcile these contradictory statements
+by an indefinite extension of the term "correlation," than we found it
+to be in the cases previously quoted. It might indeed be logically
+possible, howsoever biologically absurd, to attribute the tail of a
+peacock--with all its elaboration of structure and pattern of colour,
+with all the drain that its large size and weight makes upon the vital
+resources of the bird, with all the increased danger to which it exposes
+the bird by rendering it more conspicuous, more easy of capture, &c.--to
+correlation with some useful character peculiar to peacocks. But to say
+that it is due to correlation with general "vitality," is merely to
+discharge the doctrine of correlation of any assignable meaning.
+Vitality, or "perfect adaptation to the conditions of existence," is
+obviously a prime condition to the occurrence of a peacock's tail, as it
+is to the occurrence of a peacock itself; but this is quite a different
+thing from saying that the specific characters which are presented by a
+peacock's tail, although useless in themselves, are correlated with some
+other and useful specific characters of the same bird--as we saw in a
+previous chapter with reference to secondary sexual characters in
+general. Therefore, when Mr. Wallace comes to the obvious question why
+it is that even in "allied species," which must be in equally "perfect
+adaptation to the conditions of existence," there are no such "wonderful
+superfluities of plumage," he falls back--as he previously fell back--on
+whatever unknown _causes_ it may have been which produced the peacock's
+tail, when the primary _condition_ to their operation has been furnished
+by "complete success in the battle for life."
+
+I have quoted the above passages, not so much for the sake of exposing
+fundamental inconsistencies on the part of an adversary, as for the sake
+of observing that they constitute a much truer exposition of "Darwinism"
+than do the contradictory views expressed in some other parts of the
+work bearing that title. For even if characters of so much size and
+elaboration as the tail of a peacock, the plumes of a bird of paradise
+&c., are admitted to be due to non-utilitarian causes, much more must
+innumerable other characters of incomparably less size and elaboration
+be mere "superfluities." Without being actually deleterious, "a large
+proportional number of specific characters," whose utility is not
+apparent, must _a fortiori_ have been due to "individual variation," to
+"general laws which determine the production" of such characters--or, in
+short, to some causes other than natural selection. And this, I say, is
+a doctrine much more in harmony with "Darwinism" than is the
+contradictory doctrine which I am endeavouring to resist.
+
+But once again, and still more generally, after saying of "the delicate
+tints of spring foliage, and the intense hues of autumn," that "as
+colours they are unadaptive, and appear to have no more relation to the
+well-being of plants themselves than do the colours of gems and
+minerals," Mr. Wallace proceeds thus:--
+
+     "We may also include in the same category those algae and fungi
+     which have bright colours--the red snow of the Arctic regions, the
+     red, green, or purple seaweeds, the brilliant scarlet, yellow,
+     white or black agarics, and other fungi. All these colours are
+     probably the direct results of chemical composition or molecular
+     structure, and being thus normal products of the vegetable
+     organism, need no special explanation from our present point of
+     view; and the same remark will apply to the varied tints of the
+     bark of trunks, branches and twigs, which are often of various
+     shades of brown and green, or even vivid reds and yellows[138]."
+
+    [138] _Darwinism_, p. 302.
+
+Here, as Mr. Gulick has already observed, "Mr. Wallace seems to admit
+that instead of useless specific characters being unknown, they are so
+common and so easily explained by 'the chemical constitution of the
+organism' that they claim no special attention[139]." And whatever
+answer Mr. Wallace may make to this criticism, I do not see how he is to
+meet the point at present before us--namely, that, upon his own showing,
+there are in nature numberless instances of "characters which are
+useless without being hurtful," and which nevertheless present absolute
+"constancy." If, in order to explain the contradiction, he should fall
+back upon the principle of correlation, the case would not be in any way
+improved. For, here again, if the term correlation were extended so as
+to include "the chemical constitution or the molecular structure of the
+organism," it would thereby be extended so as to discharge all Darwinian
+significance from the term.
+
+    [139] _American Journal of Science_, Vol. XL. art. I. on _The
+          Inconsistencies of Utilitarianism as the Exclusive Theory of
+          Organic Evolution_.
+
+
+_Summary._
+
+I will conclude this discussion of the Utility question by
+recapitulating the main points in an order somewhat different from that
+in which they have been presented in the foregoing chapters. Such a
+variation may render their mutual connexions more apparent. But it is
+only to the main points that allusion will here be made, and, in order
+the better to show their independent character, I will separately number
+them.
+
+       *       *       *       *       *
+
+1. The doctrine of utility as universal, whether with respect to species
+only or likewise with respect to specific characters, is confessedly an
+_a priori_ doctrine, deduced by way of general reasoning from the theory
+of natural selection.
+
+2. Being thus founded exclusively on grounds of deduction, the doctrine
+cannot be combated by any appeal to facts. For this question is not one
+of fact: it is a question of reasoning. The treatment of our subject
+matter is logical: not biological.
+
+3. The doctrine is both universal and absolute. According to one form of
+it _all_ species, and according to another form of it _all_ specific
+characters, must _necessarily_ be due to the principle of utility.
+
+4. The doctrine in both its forms is deduced from a definition of the
+theory of natural selection as a theory, and the sole theory, of the
+origin of _species_; but, as Professor Huxley has already shown, it does
+not really follow, even from this definition, that all specific
+_characters_ must be "necessarily useful." Hence the two forms of the
+doctrine, although coincident with regard to species, are at variance
+with one another in respect of specific characters. Thus far, of course,
+I agree with Professor Huxley; but if I have been successful in showing
+that the above definition of the theory of natural selection is
+logically fallacious, it follows that the doctrine in both its forms is
+radically erroneous. The theory of natural selection is not, accurately
+speaking, a theory of the origin of species: it is a theory of the
+origin and cumulative development of adaptations, to whatever order of
+taxonomic division these may happen to belong. Thus the premisses of the
+deduction which we are considering collapse: the principle of utility is
+shown not to have any other or further reference to species, or to
+specific characters, than it has to fixed varieties, genera, families,
+&c., or to the characters severally distinctive of each.
+
+5. But, quitting all such antecedent considerations, we next proceeded
+to examine the doctrine _a posteriori_, taking the arguments which have
+been advanced in favour of the doctrine, other than those which rest
+upon the fallacious definition. These arguments, as presented by Mr.
+Wallace, are two in number.
+
+First, it is represented that natural selection must occupy the whole
+field, because no other principle of change can be allowed to operate in
+the presence of natural selection. Now I fully agree that this statement
+holds as regards any principle of change which is deleterious, but I
+cannot agree that it does so as regards any such principle which is
+merely neutral. No reason has ever been shown why natural selection
+should interfere with "indifferent" characters--to adopt Professor
+Huxley's term--supposing such to have been produced by any of the
+agencies which we shall presently have to name. Therefore this
+argument--or rather assertion--goes for nothing.
+
+Mr. Wallace's second argument is, that utility is the only principle
+which can endow specific characters with their characteristic stability.
+But this again is mere assertion. Moreover, it is assertion opposed
+alike to common sense and to observable fact. It is opposed to common
+sense, because it is obvious that any other principle would equally
+confer stability on characters due to it, provided that its action is
+constant, as Darwin expressly held. Again, this argument is opposed to
+fact, because we know of thousands of cases where peculiar characters
+are stable, which, nevertheless, cannot possibly be due to natural
+selection. Of such are the Porto Santo rabbits, the niata cattle, the
+ducks in St. James' Park, turkeys, dogs, horses, &c., and, in the case
+of plants, wheat, cabbage, maize, &c., as well as all the hosts of
+climatic varieties, both of animals and plants, in a state of nature.
+Indeed, on taking a wide survey of the facts, we do not find that the
+principle of utility is any better able to confer stability of character
+than are many other principles, both known and unknown. Nay, it is
+positively less able to do so than are some of these other principles.
+Darwin gives two very probable reasons for this fact; but I need not
+quote them a second time. It is enough to have seen that this argument
+from stability or constancy is no less worthless than the previous one.
+Yet these are the only two arguments of a corroborative kind which Mr.
+Wallace adduces whereby to sustain his "necessary deduction."
+
+6. At this point, therefore, it may well seem that we need not have
+troubled ourselves any further with a generalization which does not
+appear to have anything to support it. And to this view of the case I
+should myself agree, were it not that many naturalists now entertain the
+doctrine as an essential article of their Darwinian creed. Hence, I
+proceeded to adduce considerations _per contra_.
+
+Seeing that the doctrine in question can only rest on the assumption
+that there is no cause other than natural selection which is capable of
+originating any single species--if not even so much as any single
+specific character--I began by examining this assumption. It was shown
+first that, on merely antecedent grounds, the assumption is "infinitely
+precarious." There is absolutely no justification for the statement that
+in all the varied and complex processes of organic nature natural
+selection is the only possible cause of specific change. But, apart
+altogether from this _a priori_ refutation of the dogma, our analysis
+went on to show that, in point of actual fact, there are not a few
+well-known causes of high generality, which, while having no connexion
+with the principle of utility, are demonstrably capable of originating
+species and specific characters--if by "species" and "specific
+characters" we are to understand organic types which are ranked as
+species, and characters which are described as diagnostic of species.
+Such causes I grouped under five different headings, viz. Climate, Food,
+Sexual Selection, Isolation, and Laws of Growth. Sexual Selection and
+Isolation are, indeed, repudiated by Mr. Wallace; but, in common I
+believe with all biologists, he accepts the other three groups of causes
+as fully adequate to produce such kinds and degrees of modification as
+are taken to constitute specific distinction. And this is amply
+sufficient for our present purposes. Besides, under the head of Sexual
+Selection, it does not signify in the present connexion whether or not
+we accept Darwin's theory on this subject. For, in any case, the facts
+of secondary sexual characters are indisputable: these characters are,
+for the most part, specific characters: and they cannot be explained by
+the principle of utility. Even Mr. Wallace does not attempt to do so;
+and the explanation which he does give is clearly incompatible with his
+doctrine touching the necessarily life-serving value of all specific
+characters. Lastly, the same has to be said of the Laws of Growth. For
+we have just seen that on the grounds of this principle likewise Mr.
+Wallace abandons the doctrine in question. As regards Isolation, much
+more remains to be said in the ensuing portion of this work, while, as
+regards Climatic Variation, there are literally innumerable cases where
+changes of specific type are known to have been caused by this means.
+
+7. To the latter class of cases, however, it will be objected that these
+changes of specific type, although no doubt sufficiently "stable" so
+long as the changed conditions remain constant, are found by experiment
+not to be hereditary; and this clearly makes all the difference between
+a true specific change and a merely fictitious appearance of it.
+
+Well, in the first place, this objection can have reference only to the
+first two of the five principles above stated. It can have no reference
+to the last three, because of these heredity constitutes the very
+foundation. This consideration ought to be borne in mind throughout. But
+now, in the second place, even as regards changes produced by climate
+and food, the reply is nugatory. And this for three reasons, as follows.
+
+(_a_) No one is thus far entitled to conclude against the possible
+transmission of acquired characters; and, so long as there is even so
+much as a possibility of climatic (or any other admittedly
+non-utilitarian) variations becoming in this way hereditary, the reply
+before us merely begs the question.
+
+(_b_) Even supposing, for the sake of argument, that acquired characters
+can never in any case become congenital, there remains the strong
+probability--sanctioned as such even by Weismann--that changed
+conditions of life may not unfrequently act upon the material of
+heredity itself, thus giving rise to specific changes which are from
+the first congenital, though not utilitarian. Indeed, there are not a
+few facts (Hoffmann's plants, Weismann's butterflies, &c.), which can
+only be explained either in this way, or as above (_a_). And in the
+present connexion it is immaterial which of these alternative
+explanations we choose to adopt, seeing that they equally refute our
+opponents' objection. And not only do these considerations--(_a_) and
+(_b_)--refute this particular objection; they overturn on new and
+independent grounds the whole of our opponents' generalization. For the
+generalization is, that the principle of utility, acting through natural
+selection, is "necessarily" the sole principle which can be concerned in
+hereditary changes of specific type. But here we perceive both a
+possibility (_a_) and a probability (_b_), if not indeed a certainty,
+that quite other principles have been largely concerned in the
+production of such changes.
+
+(_c_) Altogether apart from these considerations, there remains a much
+more important one. For the objection that fixed--or "stable"--climatic
+varieties differ from true species in not being subject to heredity,
+raises the question--What are we to understand by a "species"? This
+question, which was thus far purposely left in abeyance, had now to be
+dealt with seriously. For it would clearly be irrational in our
+opponents to make this highly important generalization with regard to
+species and specific characters, unless they are prepared to tell us
+what they mean by species, and therefore by characters as specific. In
+as far as there is any ambiguity on this point it makes entirely for
+our side in the debate, because even any small degree of uncertainty
+with regard to it would render the generalization in question
+proportionally unsound. Yet it is notorious that no word in existence is
+more vague, or more impossible to define, than the word "species." The
+very same men who at one time pronounce their great generalization with
+regard to species, at another time asseverate that "a species is not a
+definite entity," but a merely abstract term, serving to denote this
+that and the other organic type, which this that and the other
+systematist regards as deserving such a title. Moreover it is
+acknowledged that systematists differ among themselves to a wide extent
+as to the kinds and degrees of peculiarity which entitle a given form to
+a specific rank. Even in the same department of systematic work much
+depends on merely individual taste, while in different departments
+widely different standards of delimination are in vogue. Hence, our
+_reductio ad absurdum_ consists in this--that whether a given form is to
+be regarded as necessarily due to natural selection, and whether all its
+distinctive characters are to be regarded as necessarily utilitarian
+characters, will often depend on whether it has been described by
+naturalist A or by naturalist B. There is no one criterion--there is not
+even any one set of criteria--agreed upon by naturalists for the
+construction of specific types. In particular, as regards the principle
+of heredity, it is not known of one named species in twenty--probably
+not in a hundred--whether its diagnostic characters are hereditary
+characters; while, on the other hand, even in cases where experiment has
+proved "constant varieties" to be hereditary--and even also
+cross-sterile with allied varieties--it is only some three or four
+living botanists who for these reasons advocate the elevation of such
+varieties to the rank of species. In short, as we are not engaged on any
+abstract question touching the principles on which species ought to have
+been constituted by their makers, but upon the actual manner in which
+they have been, the criterion of heredity must needs be disregarded in
+the present discussion, as it has been in the work of systematists. And
+the result of this is, that any objection to our introducing the facts
+of climatic variation in the present discussion is excluded. In
+particular, so far as any question of heredity is concerned, all these
+facts are as assuredly as they are cogently relevant. It is perfectly
+certain that there is "a large proportional number" of named
+species--particularly of plants--which further investigation would
+resolve into climatic varieties. With the advance of knowledge, "bad
+species" are always increasing at the expense of "good species," so that
+we are now justified in concluding with Kerner, Haeckel, and other
+naturalists best qualified to speak on this subject, that if we could
+know as much about the past history and present relations of the
+remaining good species as we do about the bad, all the former, without
+exception, would become resolved into the latter. In point of fact, and
+apart altogether from the inductive experience on which this conclusion
+is based, the conclusion follows "as a necessary deduction" from the
+general theory of descent. For this theory essentially consists in
+supposing either the past or the present existence of intermediate
+varietal forms in all cases, with the consequence that "good species"
+serve merely to mark _lacunae_ in our knowledge of what is everywhere a
+finely graduated process of transmutation. Hence, if we place this
+unquestionably "necessary deduction" from the general theory of descent
+side by side with the alleged "necessary deduction" from the theory of
+natural selection, we cannot avoid the following absurdity--Whether or
+not a given form is to be regarded as necessarily due to natural
+selection, and all its characters necessarily utilitarian, is to be
+determined, and determined solely, by the mere accident of our having
+found, or not having found, either in a living or in a fossil state, its
+varietal ancestry.
+
+8. But this leads us to consider the final and crowning incongruities
+which have been dealt with in the present chapter. For here we have
+seen, not only that our opponents thus draw a hard and fast line between
+"varieties" and "species" in regard to "necessary origin" and "necessary
+utility," but that they further draw a similar line between "species"
+and "genera" in the same respects. Yet, in accordance with the general
+theory of evolution, it is plainly as impossible to draw any such line
+in the one case as it is to do so in the other. Just as fixed varieties
+are what Darwin called "incipient species," so are species incipient
+genera, genera incipient families, and so on. Evolutionists must believe
+that the process of evolution is everywhere the same. Nevertheless,
+while admitting all this, the school of Huxley contradicts itself by
+alleging some unintelligible exception in the case of "species," while
+the school of Wallace presses this exception so as to embrace "specific
+characters." Indeed Mr. Wallace, while maintaining that all specific
+characters must necessarily be useful, maintains at the same time that
+any number of varietal characters on the one hand, and a good half of
+generic characters on the other, are probably useless. Thus he
+contradicts his argument from the "constancy of specific characters"
+(seeing that generic characters are still more constant), as later on we
+saw that he contradicts his deductive generalization touching their
+necessary utility, by giving a non-utilitarian explanation of whole
+multitudes of specific characters. I need not, however, again go over
+the ground so recently traversed; but will conclude by once more
+recurring to the only explanation which I have been able to devise of
+the otherwise inexplicable fact, that in regard to this subject so many
+naturalists still continue to entangle themselves in the meshes of
+absurdity and contradiction.
+
+       *       *       *       *       *
+
+The only conceivable explanation is, that these naturalists have not yet
+wholly divested themselves of the special creation theory. Although
+professing to have discarded the belief that "species" are "definite
+entities," differing in kind from "varieties" on the one hand and from
+"genera" on the other, these writers are still imbued with a vague
+survival of that belief. They well know it to belong to the very essence
+of their new theory that "species" are but "pronounced varieties," or,
+should we prefer it, "incipient genera"; but still they cannot
+altogether escape the pre-Darwinian conception of species as organic
+units, whose single mode of origin need not extend to other taxonomic
+groups, and whose characters therefore present some exceptional
+significance to the scientific naturalist. So to speak, such divinity
+doth still hedge a species, that even in the very act of declaring it
+but an idol of their own creation, these naturalists bow before their
+fetish as something that is unique--differing alike in its origin and in
+its characters from the varieties beneath and the genera above. The
+consequence is that they have endeavoured to reconcile these
+incompatible ideas by substituting the principle of natural selection
+for that of super-natural creation, where the particular case of
+"species" is concerned. In this way, it vaguely seems to them, they are
+able to save the doctrine of some one mode of origin as appertaining to
+species, which need not "necessarily" appertain to any other taxonomic
+division. All other such divisions they regard, with their pre-Darwinian
+forefathers, as merely artificial constructions; but, likewise with
+these forefathers, they look upon species as natural divisions, proved
+to be such by a single and necessary mode of origin. Hence, Mr. Wallace
+expressly defines a species with reference to this single and necessary
+mode of origin (_see_ above, p. 235), although he must be well aware
+that there is no better, or more frequent, proof of it in the case of
+species, than there is in that of somewhat less pronounced types on the
+one hand (fixed varieties), or of more pronounced types on the other
+(genera, families, &c.). Hence, also, the theory of natural selection is
+defined as _par excellence_ a theory of the origin of species; it is
+taken as applying to the particular case of the origin of species in a
+peculiarly stringent manner, or in a manner which does not apply to the
+origin of any other groups. And I believe that an important accessory
+reason of the continuance of this view for more than thirty years after
+the publication of the _Origin of Species by means of Natural
+Selection_, is to be found in the title of that work. "Natural
+Selection" has thus become verbally associated with "Origin of Species,"
+till it is thoughtlessly felt that, in some way or another, natural
+selection must have a peculiar reference to those artificially
+delineated forms which stand anywhere between a fixed variety and a
+so-called genus. This verbal association has no doubt had the effect of
+still further preserving the traditional halo of mystery which clings to
+the idea of a "species." Hence it comes that the title which Darwin
+chose--and, looking to the circumstances of the time, wisely chose--for
+his great work, has subsequently had the effect of fostering the very
+idea which it was the object of that work to dissipate, namely, that
+species are peculiar entities, which differ more or less in origin or
+kind from all other taxonomic groups. The full title of this work
+is--_The Origin of Species by means of Natural Selection: or the
+Preservation of Favoured Races in the Struggle for Life_. Now, supposing
+that instead of this its author had chosen some such title as the
+following:--_The Origin of Organic Types by means of Adaptive Evolution:
+or Survival of the Fittest Forms in the Struggle for Life_. Of course
+this would have been a bad substitute from various points of view; but
+could any objection have been urged against it from our present point of
+view? I do not see that there could. Yet, if such had been the title, I
+have little doubt that we should never have heard of those great
+generalizations with regard to species and specific characters, the
+futility of which it has been the object of these chapters to expose.
+
+       *       *       *       *       *
+
+In conclusion, it only remains to reiterate that in thus combating what
+appears to me plainly erroneous deductions from the theory of natural
+selection, I am in no wise combating that theory itself. On the
+contrary, I hope that I am rendering it no unimportant service by
+endeavouring to relieve it of a parasitic growth--an accretion of false
+logic. Regarding as I do the theory of natural selection as, primarily,
+a theory of the origin (or cumulative development) of adaptations, I see
+in merely non-adaptive characters--be they "specific" or other--a
+comparatively insignificant class of phenomena, which may be due to a
+great variety of incidental causes, without any further reference to the
+master-principle of natural selection than that in the presence of this
+principle none of these non-adaptive characters can be actively
+deleterious. But that there may be "any number of indifferent
+characters" it is no part of the theory of natural selection to deny;
+and all attempts to foist upon it _a priori_ "deductions" opposed alike
+to the facts of nature and to the logic of the case, can only act to the
+detriment of the great generalization which was expressly guarded from
+such fallacies by the ever-careful judgement of Darwin.
+
+
+
+
+APPENDICES AND NOTES
+
+
+
+
+APPENDIX I.
+
+ON PANMIXIA.
+
+
+There are several points of considerable theoretical importance
+connected with Panmixia, which were omitted from the text, in order to
+avoid distracting attention from the main issue which is there under
+consideration. These side issues may now be appropriately presented in
+the form in which they were published in _Nature_, March 13, 1890[140].
+After stating, in almost the same words, what has already been said in
+Chapter X, this paper proceeds, with the exception of a few verbal
+alterations, as follows.
+
+    [140] Vol. xli. p. 438.
+
+     "There is, however, one respect in which Professor Weismann's
+     statement of the principle of panmixia differs from that which was
+     considered by Mr. Darwin; and it is this difference of
+     statement--which amounts to an important difference of theory--that
+     I now wish to discuss.
+
+     "The difference in question is, that while Professor Weismann
+     believes the cessation of selection to be capable of inducing
+     degeneration down to the almost complete disappearance of a
+     rudimentary organ, I have argued that, _unless assisted by some
+     other principle_, it can at most only reduce the degenerating organ
+     to considerably above one-half its original size--or probably not
+     through so much as one-quarter. The ground of this argument (which
+     is given in detail in the _Nature_ articles of 1873-1874) is, that
+     panmixia depends for its action upon fortuitous variations round an
+     ever-diminishing average--the average thus diminishing because it
+     is no longer _sustained_ by natural selection. But although no
+     longer sustained by _natural selection_, it does continue to be
+     sustained by _heredity_; and therefore, as long as the force of
+     heredity persists unimpaired, fortuitous variations alone--or
+     variation which is no longer controlled by natural
+     selection--cannot reduce the dwindling organ to so much as one-half
+     of its original size; indeed, as above foreshadowed, the balance
+     between the positive force of heredity and the negative effects of
+     promiscuous variability will most likely be arrived at above the
+     middle line thus indicated. Only if for any reason the force of
+     heredity begins to fail can the average round which the cessation
+     of selection works become a progressively diminishing average. In
+     other words, so long as the original force of heredity as regards
+     the useless organ remains unimpaired, the mere withdrawal of
+     selection cannot reduce the organ much below the level of
+     efficiency above which it was previously _maintained_ by the
+     _presence_ of selection. If we take this level to be 80 or 90 per
+     cent. of the original size, cessation of selection will reduce the
+     organ through the 10 or 20 per cent., and there leave it
+     fluctuating about this average, unless for any reason the force of
+     heredity begins to fail--in which case, of course, the average will
+     progressively fall in proportion to the progressive weakening of
+     this force.
+
+     "Now, according to my views, the force of heredity under such
+     circumstances is always bound to fail, and this for two reasons. In
+     the first place, it must usually happen that when an organ becomes
+     useless, natural selection as regards that organ will not only
+     _cease_, but become _reversed_. For the organ is now absorbing
+     nutriment, causing weight, occupying space, and so on, _uselessly_.
+     Hence, even if it be not also a source of actual danger, 'economy
+     of growth' will determine a reversal of selection against an organ
+     which is now not merely useless, but deleterious. And this
+     degenerating influence of the reversal of selection will throughout
+     be assisted by the cessation of selection, which will now be always
+     acting round a continuously sinking average. Nevertheless, a point
+     of balance will eventually be reached in this case, just as it was
+     in the previous case where the cessation of selection was supposed
+     to be working alone. For, where the reversal of selection has
+     reduced the diminishing organ to so minute a size that its presence
+     is no longer a source of detriment to the organism, the cessation
+     of selection will carry the reduction a small degree further; and
+     then the organ will remain as a 'rudiment.' And so it will remain
+     permanently, unless there be some further reason why the still
+     remaining force of heredity should be abolished. This further (or
+     second) reason I found in the consideration that, however enduring
+     we may suppose the force of heredity to be, we cannot suppose that
+     it is actually everlasting; and, therefore, that we may reasonably
+     attribute the eventual disappearance of rudimentary organs to the
+     eventual failure of heredity itself. In support of this view there
+     is the fact that rudimentary organs, although very persistent, are
+     not everlasting. That they should be very persistent is what we
+     should expect, if the hold which heredity has upon them is great in
+     proportion to the time during which they were originally useful,
+     and thus firmly stamped upon the organization by natural selection
+     causing them to be strongly inherited in the first instance. For
+     example, we might expect that it would be more difficult finally to
+     eradicate the rudiment of a wing than the rudiment of a feather;
+     and accordingly we find it a general rule that long-enduring
+     rudiments are rudiments of organs distinctive of the higher
+     taxonomic divisions--i.e. of organs which were longest in building
+     up, and therefore longest sustained in a state of working
+     efficiency.
+
+     "Thus, upon the whole, my view of the facts of degeneration remains
+     the same as it was when first published in these columns seventeen
+     years ago, and may be summarized as follows.
+
+     "The cessation of selection when working alone (as it probably does
+     during the first centuries of its action upon structures or colours
+     which do not entail any danger to, or perceptible drain upon, the
+     nutritive resources of the organism) cannot cause degeneration
+     below, probably, some 10 to 20 per cent. But if from the first the
+     cessation of selection has been assisted by the _reversal_ of
+     selection (on account of the degenerating structure having
+     originally been of a size sufficient to entail a perceptible drain
+     on the nutritive resources of the organism, having now become a
+     source of danger, and so forth), the two principles acting together
+     will continue to reduce the ever-diminishing structure down to the
+     point at which its presence is no longer a perceptible disadvantage
+     to the species. When that point is reached, the reversal of
+     selection will terminate, and the cessation of selection will not
+     then be able of itself to reduce the organ through more than at
+     most a very few further percentages of its original size. But,
+     after this point has been reached, the now total absence of
+     selection, either for or against the organ, will sooner or later
+     entail this further and most important consequence, a failure of
+     heredity as regards the organ. So long as the organ was of use, its
+     efficiency was constantly _maintained_ by the _presence_ of
+     selection--which is merely another way of saying that selection was
+     constantly maintaining the force of heredity as regards that organ.
+     But as soon as the organ ceased to be of use, selection ceased to
+     maintain the force of heredity; and thus, sooner or later, that
+     force began to waver or fade. Now it is this wavering or fading of
+     the force of heredity, thus originally due to the cessation of
+     selection, that in turn co-operates with the still continued
+     cessation of selection in reducing the structure below the level
+     where its reduction was left by the actual reversal of selection.
+     So that from that level downwards the cessation of selection, and
+     the consequent failing of heredity, act and react in their common
+     work of causing obsolescence. In the case of newly added
+     characters, the force of heredity will be less than in that of more
+     anciently added characters; and thus we can understand the long
+     endurance of 'vestiges' characteristic of the higher taxonomic
+     divisions, as compared with those characteristic of the lower. But
+     in all cases, if time enough be allowed under the cessation of
+     selection, the force of heredity will eventually fall to zero, when
+     the hitherto obsolescent structure will finally become obsolete. In
+     cases of newly added and comparatively trivial characters, with
+     regard to which reversal of selection is not likely to take place
+     (e.g. slight differences of colour between allied species),
+     cessation of selection is likely to be very soon assisted by a
+     failure in the force of heredity; seeing that such newly added
+     characters will not be so strongly inherited as are the more
+     ancient characters distinctive of higher taxonomic groups.
+
+     "Let us now turn to Weismann's view of degeneration. First of all,
+     he has omitted to perceive that 'panmixia' alone (if unassisted
+     either by reversed selection or an inherent diminishing of the
+     force of heredity) cannot reduce a functionless organ to the
+     condition of a _rudiment_. Therefore he everywhere represents
+     panmixia (or the mere _cessation_ of selection) as of itself
+     sufficient to cause degeneration, say from 100 to 5, instead of
+     from 100 to 90 or 80, which, for the reasons above given, appeared
+     (and still appears) to me about the most that this principle can
+     accomplish, so long as the original force of heredity continues
+     unimpaired. No doubt we have here what must be regarded as a mere
+     oversight on the part of Professor Weismann; but the oversight is
+     rendered remarkable by the fact that he _does_ invoke the aid of
+     reversed selection _in order to explain the final disappearance of
+     a rudiment_. Yet it is self-evident that the reversal of selection
+     must be much more active during the initial than during the final
+     stages of degeneration, seeing that, _ex hypothesi_, the greater
+     the degree of reduction which has been attained the less must be
+     the detriment arising from any useless expenditure of nutrition,
+     &c.
+
+     "And this leads me to a second oversight in Professor Weismann's
+     statement, which is of more importance than the first. For the
+     place at which he does invoke the assistance of reversed selection
+     is exactly the place at which reversed selection must necessarily
+     have ceased to act. This place, as already explained, is where an
+     obsolescent organ has become rudimentary, or, as above supposed,
+     reduced to 5 per cent. of its original size; and the reason why he
+     invokes the aid of reversed selection at this place is in order to
+     save his doctrine of 'the stability of germ-plasm.' That the force
+     of heredity should finally become exhausted if no longer
+     _maintained_ by the _presence_ of selection, is what Darwin's
+     theory of perishable gemmules would lead us to expect, while such a
+     fact would be fatal to Weismann's theory of an imperishable
+     germ-plasm. Therefore he seeks to explain the eventual failure of
+     heredity (which is certainly a fact) by supposing that after the
+     point at which the cessation of selection alone can no longer act
+     (and which his first oversight has placed some 80 per cent. too
+     low), the reversal of selection will begin to act directly against
+     the force of heredity as regards the diminishing organ, until such
+     direct action of reversed selection will have removed the organ
+     altogether. Or, in his own words, 'The complete disappearance of a
+     rudimentary organ can only take place by the operation of natural
+     selection; this principle will lead to its diminution, inasmuch as
+     the disappearing structure takes the place and the nutriment of
+     other useful and important organs.' That is to say, the
+     rudimentary organ finally disappears, not because the force of
+     heredity is finally exhausted, but because natural selection has
+     begun to utilize this force against the continuance of the
+     organ--always picking out those congenital variations of the organ
+     which are of smallest size, and thus, by its now _reversed_ action,
+     _reversing_ the force of heredity as regards the organ.
+
+     "Now the oversight here is in not perceiving that the smaller the
+     disappearing structure becomes, the less hold must 'this principle'
+     of reversed selection retain upon it. As above observed, during the
+     earlier stages of reduction (or while co-operating with the
+     cessation of selection) the reversal of selection will be at its
+     _maximum_ of efficiency; and, as the process of diminution
+     continues, a point must eventually be reached at which the reversal
+     of selection can no longer act. Take the original mass of a now
+     obsolescent organ in relation to that of the entire organism of
+     which it then formed a part to be represented by the ratio 1:100.
+     For the sake of argument we may assume that the mass of the
+     organism has throughout remained constant, and that by 'mass' in
+     both cases is meant capacity for absorbing nutriment, causing
+     weight, occupying space, and so forth. Now, we may further assume
+     that when the mass of the organ stood to that of its organism in
+     the ratio of 1:100, natural selection was strongly reversed with
+     respect to the organ. But when this ratio fell to 1:1000, the
+     activity of such reversal must have become enormously diminished,
+     even if it still continued to exercise any influence at all. For we
+     must remember, on the one hand, that the reversal of selection can
+     only act as long as the presence of a diminishing organ continues
+     to be so injurious that variations in its size are matters of life
+     and death in the struggle for existence; and, on the other hand,
+     that natural selection in the case of the diminishing organ does
+     not have reference to the presence and the absence of the organ,
+     but only to such variations in its mass as any given generation may
+     supply. Now, the process of reduction does not end even at 1:1000.
+     It goes on to 1:10,000, and eventually 1:[infinity]. Consequently,
+     however great our faith in natural selection may be, a point must
+     eventually come for all of us at which we can no longer believe
+     that the reduction of an obsolescent organ is due to reversed
+     selection. And I cannot doubt that if Professor Weismann had
+     sufficiently considered the matter, he would not have committed
+     himself to the statement that 'the complete disappearance of a
+     rudimentary organ can only take place by the operation of natural
+     selection.'
+
+     "According to my view, the complete disappearance of a rudimentary
+     organ can only take place by the _cessation_ of natural selection,
+     which permits the eventual exhaustion of heredity, when heredity is
+     thus simply left to itself. During all the earlier stages of
+     reduction, the cessation of selection was assisted in its work by
+     the reversal of selection; but when the rudiment became too small
+     for such assistance any longer to be supplied, the rudiment
+     persisted in that greatly reduced condition until the force of
+     heredity with regard to it was eventually worn out. This appears to
+     me, as it appeared in 1873, the only reasonable conclusion that can
+     be drawn from the facts. And it is because this conclusion is fatal
+     to Professor Weismann's doctrine of the permanent 'stability' of
+     germ-plasm, while quite in accordance with all theories which
+     belong to the family of pangenesis, that I deem the facts of
+     degeneration of great importance as tests between these rival
+     interpretations of the facts of heredity. It is on this account
+     that I have occupied so much space with the foregoing discussion;
+     and I shall be glad to ascertain whether any of the followers of
+     Professor Weismann are able to controvert these views.
+
+                                                "GEORGE J. ROMANES."
+
+     "P.S.--Since the above article was sent in, Professor Weismann has
+     published in these columns (February 6) his reply to a criticism by
+     Professor Vines (October 24, 1889). In this reply he appears to
+     have considerably modified his views on the theory of degeneration;
+     for while in his Essays he says (as in the passage above quoted)
+     that 'the complete disappearance of a rudimentary organ can only
+     take place by the operation of natural selection'--i.e. only by the
+     _reversal_ of selection,--in his reply to Professor Vines he says,
+     'I believe that I have proved that organs no longer in use become
+     rudimentary, and must finally disappear, solely by 'panmixia'; not
+     through the direct action of disuse, but because natural selection
+     no longer sustains their standard structure'--i.e. solely by the
+     _cessation_ of selection. Obviously, there is here a flat
+     contradiction. If Professor Weismann now believes that a
+     rudimentary organ 'must finally disappear _solely_' through the
+     _withdrawal_ of selection, he has abandoned his previous belief
+     that 'the complete disappearance of a rudimentary organ can _only_
+     take place by the _operation_ of selection.' And this change of
+     belief on his part is a matter of the highest importance to his
+     system of theories as a whole, since it betokens a surrender of his
+     doctrine of the 'stability' of germ-plasm--or of the virtually
+     everlasting persistence of the force of heredity, and the
+     consequent necessity for a reversal of this force itself (by
+     natural selection placing its premium on _minus_ instead of on
+     _plus_ variations), in order that a rudimentary organ should
+     finally disappear. In other words, it now seems he no longer
+     believes that the force of heredity in one direction (that of
+     sustaining a rudimentary organ) can only be abolished by the active
+     influence of natural selection determining this force in the
+     opposite direction (that of removing a rudimentary organ). It seems
+     he now believes that the force of heredity, if merely left to
+     itself by the withdrawal of natural selection altogether, will
+     sooner or later become exhausted through the mere lapse of time.
+     This, of course, is my own theory of the matter as originally
+     published in these columns; but I do not see how it is to be
+     reconciled with Professor Weismann's doctrine of so high a degree
+     of stability on the part of germ-plasm, that we must look to the
+     Protozoa and the Protophyta for the original source of congenital
+     variations as now exhibited by the Metazoa and Metaphyta.
+     Nevertheless, and so far as the philosophy of degeneration is
+     concerned, I shall be very glad if (as it now appears) Professor
+     Weismann's more recent contemplation has brought his principle of
+     panmixia into exact coincidence with that of my cessation of
+     selection."
+
+Before passing on it may here be noted that, to any one who believes in
+the inheritance of acquired characters, there is open yet another
+hypothetical cause of degeneration, and one to which the final
+disappearance of vestigial organs may be attributed. Roux has shown in
+his work on _The Struggle for Existence between Parts of an Organism_
+that the principle of selection must operate in every constituent
+tissue, and as between every constituent cell of which an organism is
+composed. Now, if an organ falls into disuse, its constituent cells
+become worsted in their struggles with other cells in the organism.
+Hence, degeneration of the disused organ may progressively increase,
+quite independently of any struggle for existence on the part of the
+organism as a whole. Consequently, degeneration may proceed without any
+reference to the principle of "economized nutrition"; and, if it does
+so, and if the effects of its doing so are transmitted from generation
+to generation, the disused organ will finally disappear by means of
+Roux's principle.
+
+The long communication above quoted led to a still longer correspondence
+in the pages of _Nature_. For Professor Ray Lankester wrote[141] to
+impugn the doctrine of panmixia, or cessation of selection, _in toto_,
+arguing with much insistence that "cessation of selection must be
+supplemented by economy of growth in order to produce the results
+attributed to panmixia." In other words, he denied that panmixia alone
+can cause degeneration in any degree at all; at most, he said, it can be
+but "a condition," or "a state," which occurs when an organ or part
+ceases to be useful, and therefore falls under the degenerating
+influence of active causes, such as economy of nutrition. Or, in yet
+other words, he refused to recognize that any degenerative process can
+be due to natural selection as merely withdrawn: only when, besides
+being _withdrawn_, natural selection is _reversed_, did he regard a
+degenerative process as possible. As a result of the correspondence,
+however, he eventually[142] agreed that, if the "birth-mean" of an
+organ, in respect either of size or complexity of structure, be lower
+than the "selection-mean" while the organ is useful (a fact which he
+does not dispute); then, if the organ ceases to be useful, it will
+degenerate by the withdrawal of selection alone. Which, of course, is
+merely a re-statement of the doctrine of panmixia, or cessation of
+selection, in somewhat varied terminology--provided that the birth-mean
+be taken over a number of generations, or not only over a few following
+the selection-mean of the structure while still in its highest state of
+efficiency. For the sake of brevity I will hereafter speak of these "few
+following" generations by the term of "first generations."
+
+    [141] _Nature_, vol. xli. p. 486.
+
+    [142] _Ibid._ vol. xlii. p. 52.
+
+It remains to consider the views of Professor Lloyd Morgan upon the
+subject. In my opinion he is the shrewdest, as well as the most logical
+critic that we have in the field of Darwinian speculation; therefore, if
+possible, I should like to arrive at a full agreement with him upon this
+matter. His latest utterance with regard to it is as follows:--
+
+     "To account for the diminution of organs or structures no longer of
+     use, apart from any inherited effects of disuse, Mr. Romanes has
+     invoked the Cessation of Selection; and Mr. Francis Galton has, in
+     another connexion, summarized the effects of this cessation of
+     selection in the convenient phrase 'Regression to Mediocrity.' This
+     is the Panmixia of Professor Weismann and his followers; but the
+     phrase regression to mediocrity through the cessation of selection
+     appears to me preferable. It is clear that so long as any organ or
+     structure is subject to natural selection through elimination, it
+     is, if not actually undergoing improvement, kept at a high standard
+     of efficiency through the elimination of all those individuals in
+     which the organ in question falls below the required standard. But
+     if, from change in the environment or any other cause, the
+     character in question ceases to be subject to selection,
+     elimination no longer takes place, and the high standard will no
+     longer be maintained. There will be reversion to mediocrity. The
+     probable amount of this reversion is at present a matter under
+     discussion[143]."
+
+    [143] _Presidential Address to the Bristol Naturalists' Society_,
+          1891.
+
+So far, then, Professor Lloyd Morgan is in complete agreement with
+previous writers upon the subject. He does not doubt that the cessation
+of selection must always be a cause of degeneration: the only question
+is as to the _potency_ of this cause, or the _amount_ of degeneration
+which it is capable of effecting.
+
+Taking, first, the case of bulk or size of an organ, as distinguished
+from its organization or complexity, we have seen that Weismann
+represents the cessation of selection--even if working quite alone, or
+without any assistance from the reversal of selection--to be capable of
+reducing a fully developed organ to the state of a rudiment, or even, if
+we take his most recent view, of abolishing the organ _in toto_.
+
+Professor Lloyd Morgan, on the other hand, does not think that the
+cessation of selection alone can cause reduction further than the level
+of "mediocrity" in the first generations--or, which is much the same
+thing, further than the difference between the "birth-mean" and the
+"selection-mean" of the first generations. This amount of reduction he
+puts at 5 per cent., as "a very liberal estimate."
+
+Here, then, we have three estimates of the amount of degeneration which
+can be produced by panmixia alone, where mere size or bulk of an organ
+is concerned--say, 3 to 5 per cent., 10 to 20 per cent., and 95 per
+cent. to 0. At first sight, these differences appear simply ludicrous;
+but on seeking for the reasons of them, we find that they are due to
+different views touching the manner in which panmixia operates. The
+oversights which have led to Weismann's extremely high estimate have
+already been stated. The reason of the difference between the extremely
+low estimate of Professor Lloyd Morgan, as compared with my own
+intermediate one, is, that he supposes the power of panmixia to become
+exhausted as soon as the level of mediocrity of the first generations
+has become the general level in succeeding generations. In my view,
+however, the level of mediocrity is itself a sinking level in
+successive generations, with the result that there is no reason why the
+reducing power of panmixia should ever become exhausted, save that the
+more reduction it effects the greater is the force of heredity which
+remains to be overcome, as previously explained. Thus the only question
+between Professor Lloyd Morgan and myself is--Does the level of
+mediocrity fall in successive generations under the cessation of
+selection, or does it remain permanently where it used to be under the
+presence of selection? Does the "birth-mean" remain constant throughout
+any number of generations, notwithstanding that the sustaining influence
+of selection has been withdrawn; or does it progressively sink as a
+consequence of such withdrawal?
+
+In order to answer this question we had better begin by considering now
+the case of organization of structure, as distinguished from mere size
+of structure. Take any case where a complex organ--such as a compound
+eye--has been slowly elaborated by natural selection, and is it not
+self-evident that, when natural selection is withdrawn, the complex
+structure will deteriorate? In other words, the level of mediocrity, say
+in the hundred thousandth generation after the sustaining influence of
+natural selection has been withdrawn, will not be so high as it was in
+the first generations. For, by hypothesis, there is now no longer any
+elimination of unfavourable variations, which may therefore perpetuate
+themselves as regards any of the parts of this highly complex mechanism;
+so that it is only a matter of time when the mechanism must become
+disintegrated. I can scarcely suppose that any one who considers the
+subject will question this statement, and therefore I will not say
+anything that might be said in the way of substantiating it. But, if the
+statement be assented to, it follows that there is no need to look for
+any cause of deterioration, further than the withdrawal of selection--or
+cessation of the principle which (as we are supposing) had hitherto
+been the sole means of maintaining efficient harmony among all the
+independently variable parts of the highly complex structure.
+
+Now, I hold that the same thing is true, though in a lesser degree, as
+regards degeneration of size. That there is no difference _in kind_
+between the two cases, Professor Lloyd Morgan implicitly allows; for
+what he says is--
+
+     "In any long-established character, such as wing-power in birds,
+     brain-development, the eyes of crustacea, &c., no shortcomer in
+     these respects would have been permitted by natural selection to
+     transmit his shortcomings for hundreds of generations. All tendency
+     to such shortcomings would, one would suppose, have been bred out
+     of the race. If after this long process of selection there still
+     remains a strong tendency to deterioration, this tendency demands
+     an explanation[144]."
+
+    [144] _Presidential Address to the Bristol Naturalists' Society_,
+          1891.
+
+Here, then, deterioration as to size of structure (wings of birds), and
+deterioration as to complexity of structure (brain and eyes) are
+expressly put upon the same footing. Therefore, if in the latter case
+the "tendency to deterioration" does not "demand an explanation," beyond
+the fact that the hitherto maintaining influence has been withdrawn,
+neither is any such further explanation demanded in the former case.
+Which is exactly my own view of the matter. It is also Mr. Galton's
+view. For although, in the passage formerly quoted, Professor Lloyd
+Morgan appears to think that by the phrase "Regression to Mediocrity"
+Mr. Galton means to indicate that panmixia can cause degeneration only
+as far as the mediocrity level of the first generations, this, in point
+of fact, is not what Galton means, nor is it what he says. The phrase in
+question occurs "in another connexion," and, indeed, in a different
+publication. But where he expressly alludes to the cessation of
+selection, this is what he says. The italics are mine.
+
+     "A special cause may be assigned for the effects of use in causing
+     hereditary _atrophy_ of disused parts. It has already been shown
+     that all exceptionally developed organs tend to deteriorate:
+     consequently, those that are not _protected_ by selection will
+     _dwindle_. The level of muscular efficiency in the wing of a
+     strongly flying bird [curiously enough, the same case that is
+     chosen by Professor Lloyd Morgan to illustrate his opposite view],
+     is like the level of water in the leaky vessel of a Danaid, only
+     secured to the race by _constant effort_, so to speak. _Let the
+     effort be relaxed ever so little, and the level immediately
+     falls[145]._"
+
+    [145] _A Theory of Heredity_, Journal of Anthropological Institute,
+          1875. Vol. v. p. 345.
+
+I take it, then, that the burden of proof lies with Professor Lloyd
+Morgan to show why the withdrawal of selection is _not_ sufficient to
+account for degeneration any further than the mediocrity-level in the
+former presence of selection. Why does "the strong tendency[146] to
+deterioration demand an explanation," further than the fact that when
+all variations below the average in every generation are allowed to
+survive, they must gradually lower the average itself through a series
+of generations? To answer that any such tendency "would have been bred
+out of the race" by the previous action of selection, is to suppose that
+the function of selection is at an end when once it has built up a
+structure to the highest point of working efficiency,--that the presence
+of selection is no longer required to _maintain_ the structure at that
+point. But it is enough to ask in reply--Why, under the cessation of
+selection, does _complexity_ of structure degenerate so much more
+rapidly than _size_ of structure? Why is it, for instance, that "the
+eyes of crustacea" in dark caves have entirely disappeared, while their
+foot-stalks (when originally present) still remain? Can it be maintained
+that "for hundreds of generations" natural selection was more intent on
+developing the foot-stalks than the eyes which were mounted upon
+them--so that while the latter were left by selection with "a strong
+tendency to deterioration," the former have had this tendency "bred out
+in the race"[147]?
+
+    [146] No one has supposed that the tendency need be "strong": it has
+          only to be persistent.
+
+    [147] Of course it must be observed that degeneration of complexity
+          involves also degeneration of size, so that a more correct
+          statement of the case would be--Why, under the cessation of
+          selection, does an organ of extreme complexity degenerate much
+          more rapidly than one of much less complexity? For example,
+          under domestication the brains of rabbits and ducks appear to
+          have been reduced in some cases by as much as 50 per cent.
+          (Darwin, and Sir J. Crichton Browne.) But if it is possible to
+          attribute this effect--or part of it--to an artificial
+          selection of stupid animals, I give in the text an example
+          occurring under nature. Many other cases, however, might be
+          given to show the general rule, that under cessation of
+          selection complexity of structure degenerates more
+          rapidly--and also more thoroughly--than size of it. This, of
+          course, is what Mr. Galton and I should expect, seeing that
+          the more complex a structure the greater are the number of
+          points for deterioration to invade when the structure is no
+          longer "protected by selection." (On the other hand, of
+          course, this fact is opposed to the view that degeneration of
+          useless structures below the "birth-mean" of the first
+          generations, is exclusively due to the reversal of selection;
+          for economy of growth, deleterious effect of weight, and so
+          forth, ought to affect size of structure _much more_ than
+          complexity of it.) But I choose the above case, partly because
+          Professor Lloyd Morgan has himself alluded to "the eyes of
+          crustacea," and partly because Professor Ray Lankester has
+          maintained that the loss of these eyes in dark caves is due to
+          the reversal of selection, as distinguished from the cessation
+          of it. In view of the above parenthesis it will be seen that
+          the point is not of much importance in the present connexion;
+          but it appears to me that cessation of selection must here
+          have had at least the larger share in the process of atrophy.
+          For while the economy of nutrition ought to have removed the
+          relatively large _foot-stalks_ as rapidly as the _eyes_, I
+          cannot see that there is any advantage, other than the economy
+          of nutrition, to be gained by the rapid loss of hard-coated
+          _eyes_, even though they have ceased to be of use.
+
+To sum up. There is now no question in any quarter touching the fact
+that panmixia, or the cessation of selection, is a true cause of
+degeneration. The only question is as to the amount of degeneration
+which it is able to effect when not assisted by the reversal of
+selection, or any other cause of degeneration. Moreover, even with
+regard to this question of amount, there is no doubt on any side that
+panmixia alone causes degeneration _more rapidly_ where it has to do
+with complexity of organization, than it does where it is concerned with
+a mere reduction of mass.
+
+The question as to the amount of degeneration that is caused by the
+cessation of selection alone is without any practical importance where
+species in a state of nature are concerned, because here the cessation
+of selection is probably always associated more or less with the
+reversal of it; and it is as impossible as it is immaterial to determine
+the relative shares which these two co-operating principles take in
+bringing about the observed results. But where organisms in a state of
+domestication are concerned, the importance of the question before us is
+very great. For if the cessation of selection alone is capable of
+reducing an organ through 10 or 12 per cent. of its original size,
+nearly all the direct evidence on which Darwin relied in favour of
+use-inheritance is destroyed. On the other hand, if reduction through 5
+per cent. be deemed a "very liberal estimate" of what this principle can
+accomplish, the whole body of Darwin's direct evidence remains as he
+left it. I have now given my reasons for rejecting this lower estimate
+on the one band, and what seems to me the extravagant estimate of
+Weismann on the other. But my own intermediate estimate is enough to
+destroy the apparent proof of use-inheritance that was given by Darwin.
+Therefore it remains for those who deny Lamarckian principles, either to
+accept some such estimate, or else to acknowledge the incompatibility of
+any lower one with the opinion that there is no evidence in favour of
+these principles.
+
+
+
+
+APPENDIX II.
+
+ON CHARACTERS AS ADAPTIVE AND SPECIFIC.
+
+
+It is the object of this Appendix to state, more fully than in the text,
+the opinions with regard to this subject which have been published by
+the two highest authorities on the theory of natural selection--Darwin
+and Professor Huxley. I will take first the opinion of Professor Huxley,
+quoted _in extenso_, and then consider it somewhat more carefully than
+seemed necessary in the text.
+
+As far as I am aware, the only occasion on which Professor Huxley has
+alluded to the subject in question, is in his obituary notice of Darwin
+in the _Proceedings of the Royal Society_, Vol. XLIV, No. 269, p. xviii.
+The allusion is to my paper on _Physiological Selection_, in the
+_Journal of the Linnaean Society_, Zool. Vol. XIX, pp. 337-411. But it
+will be observed that the criticism has no reference to the theory which
+it is the object of that paper to set forth. It refers only to my
+definition of the theory of natural selection as primarily a theory of
+the origin, or cumulative development, of adaptations. This criticism,
+together with my answer thereto at the time, is conveyed in the
+following words.
+
+     "Every variety which is selected into a species is favoured and
+     preserved in consequence of being, in some one or more respects,
+     better adapted to its surroundings than its rivals. In other words,
+     every species which exists, exists in virtue of adaptation, and
+     whatever accounts for that adaptation accounts for the existence of
+     the species. To say that Darwin has put forward a theory of the
+     adaptation of species, but not of their origin, is therefore to
+     misunderstand the first principles of the theory. For, as has been
+     pointed out, it is a necessary consequence of the theory of
+     selection that every species must have some one or more structural
+     or functional peculiarities, in virtue of the advantage conferred
+     by which it has fought through the crowd of its competitors, and
+     achieved a certain duration. In this sense, it is true that every
+     species has been 'originated' by selection."
+
+     Now, in the first place, I have nowhere said that "Darwin has put
+     forward a theory of the adaptation of species, but not of their
+     origin." I said, and continue to say, that he has put forward a
+     theory of _adaptations in general_, and that where such adaptations
+     appertain to species only (i.e. are peculiar to particular
+     species), the theory becomes "_also_ a theory of the origin of the
+     species which present them." The only possible misunderstanding,
+     therefore, which can here be alleged against me is, that I fail to
+     perceive it as a "necessary consequence of the theory of selection
+     that _every_ species _must_ have some one or more structural or
+     functional _peculiarities_" of an adaptive or utilitarian kind.
+     Now, if this is a misunderstanding, I must confess to not having
+     had it removed by Mr. Huxley's exposition.
+
+     The whole criticism is tersely conveyed in the form of two sequent
+     propositions--namely, "Every species which exists, exists in virtue
+     of adaptation; and whatever accounts for that adaptation accounts
+     for the existence of the species." My answer is likewise two-fold.
+     First, I do not accept the premiss; and next, even if I did, I can
+     show that the resulting conclusion would not overturn my
+     definition. Let us consider these two points separately, beginning
+     with the latter, as the one which may be most briefly disposed of.
+
+     I. Provisionally conceding that "every species which exists, exists
+     in virtue of adaptation," I maintain that my definition of the
+     theory of natural selection still holds good. For even on the basis
+     of this concession, or on the ground of this assumption, the theory
+     of natural selection is not shown to be "_primarily_" a theory of
+     the origin of species. It follows, indeed, from the assumption--is,
+     in fact, part and parcel of the assumption--that all species have
+     been originated by natural selection; but why? _Only because
+     natural selection has originated those particular adaptive features
+     in virtue of which (by the hypothesis) species exist as species._
+     It is only in virtue of having created these features that natural
+     selection has created the species presenting them--just as it has
+     created genera, families, orders, &c., in virtue of _other_
+     adaptive features extending through progressively wider areas of
+     taxonomic division. Everywhere and equally this principle has been
+     "primarily" engaged in the evolution of adaptations, and if one
+     result of its work has been that of enabling the systematist to
+     trace lines of genetic descent under his divisions of species,
+     genera, and the rest, such a result is but "secondary" or
+     "incidental."
+
+     In short, it is "_primarily_" a theory of adaptations _wherever
+     these occur_, and only becomes "_also_" or "_incidentally_" a
+     theory of species in cases where adaptations happen to be
+     restricted in their occurrence to organic types of a certain order
+     of taxonomic division.
+
+     II. Hitherto, for the sake of argument, I have conceded that, in
+     the words of my critic, "it is a necessary consequence of the
+     theory of selection that every species must have some one or more
+     structural or functional peculiarities" of an adaptive kind. But
+     now I will endeavour to show that this statement does not "follow
+     as a necessary consequence" from "the theory of selection."
+
+     Most obviously "it follows" from the theory of selection that
+     "every variety which is selected into a species is favoured and
+     preserved in consequence of being, in some one or more respects,
+     better adapted to its surroundings than its rivals." This, in fact,
+     is no more than a re-statement of the theory itself. But it does
+     _not_ follow that "every species which exists, exists in virtue of
+     adaptation" _peculiar to that species_; i.e. that every species
+     which exists, exists _in virtue of having been "selected_." This
+     may or may not be true as a matter of fact: as a matter of logic,
+     the inference is not deducible from the selection theory. Every
+     variety which is "_selected into_" a species must, indeed, present
+     some such peculiar advantage; but this is by no means equivalent to
+     saying, "in other words," that every variety which _becomes_ a
+     species must do so. For the latter statement imports a completely
+     new assumption--namely, that every variety which _becomes_ a
+     species must do so because it has been "_selected into_" a species.
+     In short, what we are here told is, that if we believe the
+     selection principle to have given origin to some species, we must
+     further believe, "as a necessary consequence," that it has given
+     origin to all species.
+
+The above reply, which is here quoted _verbatim_ from _Nature_, Vol. 38,
+p. 616-18, proceeded to show that it does not belong to "the first
+principles of the theory of natural selection" to deny that no other
+cause than natural selection can possibly be concerned in the origin of
+species; and facts were given to prove that such unquestionably has been
+the case as regards the origin of "local" or "permanent" _varieties_.
+Yet such varieties are what Darwin correctly terms "incipient" species,
+or species in process of taking _origin_. Therefore, if Professor
+Huxley's criticism is to stand at all, we must accept it "as a necessary
+consequence of the theory of selection," that every such _variety_
+"which exists, exists in virtue of adaptation"--a statement which is
+_proved_ to be untrue by the particular cases forthwith cited. But as
+this point has been dealt with much more fully in the text of the
+present treatise, I shall sum up the main points in a few words.
+
+The criticism is all embodied in two propositions--namely, (_a_) that
+the theory of natural selection carries with it, as a "necessary
+consequence," the doctrine that survival of the fittest has been the
+cause of the origin of _all_ species; and (_b_) that therefore it
+amounts to one and the same thing whether we define the theory as a
+theory of species or as a theory of adaptations. Now, as a mere matter
+of logical statement, it appears to me that both these propositions are
+unsound. As regards the first, if we hold with Darwin that other causes
+have co-operated with natural selection in the origination of some (i.
+e. many) species, it is clearly no part of the theory of natural
+selection to assume that none of these causes can ever have acted
+independently. In point of fact, as we have seen in the foregoing
+chapters, such has probably and frequently been the case under the
+influences of isolation, climate, food, sexual selection, and laws of
+growth; but I may here adduce some further remarks with regard to yet
+another possible cause. If the Lamarckian principles are valid at all,
+no reason can be shown why in some cases they may not have been
+competent _of themselves_ to induce morphological changes of type by
+successive increments, until a transmutation of species is effected by
+their action alone--as, indeed, Weismann believes to have been the case
+with all the species of Protozoa[148]. That such actually has often been
+the case also with numberless species of Metozoa, is the belief of the
+neo-Lamarckians; and whether they are right or wrong in holding this
+belief, it is equally certain that, _as a matter of logical reasoning_,
+they are not compelled by it to profess any _disbelief_ in the agency of
+natural selection. They may be mistaken as to the facts, as Darwin in a
+lesser degree may have been similarly mistaken; but just as Darwin has
+nowhere committed himself to the statement that _all_ species must
+_necessarily_ have been originated by natural selection, so these
+neo-Lamarckians are perfectly logical in holding that _some_ species may
+have been wholly caused by the inheritance of acquired characters, as
+_other_ species may have been wholly caused by the natural selection of
+congenital characters. In short, unless we begin by assuming (with
+Wallace and against Darwin) that there _can be no other cause_ of the
+origin of species than that which is furnished by natural selection, we
+have no basis for Professor Huxley's statement "that every species has
+been originated by selection"; while, if we do set out with this
+assumption, we end in a mere tautology. What ought to be done is to
+prove the validity of this assumption; but, as Professor Huxley makes
+no attempt to do this, his criticism amounts to mere begging of the
+question.
+
+    [148] Since the above was written Professor Weismann has transferred
+          this doctrine from the Protozoa to their ancestors.
+
+And now, as regards the second point (_b_), even if we grant the
+assumption that natural selection is the only possible cause of the
+origin of species--or, which is the same thing, that every species has
+been originated by natural selection,--is it likewise the same thing
+whether we define the theory of natural selection as a theory of species
+or as a theory of adaptations? Professor Huxley's criticism endeavours
+to show that it is; but a little consideration is enough to show that it
+is not. What does follow from the assumption is, that, _so far as
+specific characters are concerned_, it is one and the same thing to say
+that the theory is a theory of species, and to say that it is a theory
+of adaptations. But specific characters are not conterminous with
+adaptive characters; for innumerable adaptive characters are not
+distinctive of species, but of genera, families, orders, classes, and
+sub-kingdoms. Therefore, if it is believed (as, of course, Professor
+Huxley believes) that the theory in question explains the evolution of
+all adaptive characters, obviously it is not one and the same thing to
+define it indifferently as a theory of species or as a theory of
+adaptations.
+
+Now, all this is not merely a matter of logic chopping. On the contrary,
+the question whether we are to accept or to reject the deduction that
+all species must necessarily have owed their origin to natural
+selection, is a question of no small importance to the general theory of
+evolution. And our answer to this question must be determined by that
+which we give to the ulterior question--Is the theory of natural
+selection to be defined as a theory of species, or as a theory of
+adaptations?
+
+       *       *       *       *       *
+
+We now pass on to our consideration of Darwin's opinion touching the
+question, as stated by himself,--"The doctrine of utility, how far
+true?" As I cannot ascertain that Darwin has anywhere expressed an
+opinion as to whether natural selection has been necessarily concerned
+in the origin of all _species_, the issue here is as to whether he held
+this with regard to all _specific characters_. It will be remembered
+that while opposing this doctrine as erroneous both in logic and in
+fact, I have represented that it is not a doctrine which Darwin
+sanctioned; but, on the contrary, that it is one which he expressly
+failed to sanction, by recognizing the frequent inutility of specific
+characters. Mr. Wallace, on the other hand, alleges that Darwin did
+believe in the universal--as distinguished from the general--utility of
+such characters. And he adds that he has "looked in vain in Mr. Darwin's
+works" for any justification of my statements to the contrary[149].
+Therefore I will endeavour to show that Mr. Wallace's search has not
+been a very careful one.
+
+    [149] _Darwinism_, p. 131. He says:--"I have looked in vain in Mr.
+          Darwin's works for any such acknowledgement" (i.e. "that a
+          large proportion of specific distinctions must be conceded
+          useless to the species presenting them").
+
+We must remember, however, that it was not until the appearance of my
+paper on _Physiological Selection_, four years after Darwin's death,
+that the question now in debate was raised. Consequently, he never had
+occasion to deal expressly with this particular question--viz. whether
+"the doctrine of utility" has any _peculiar_ reference to _specific_
+characters--as he surely would have done had he entertained the
+important distinction between specific and all other characters which
+Mr. Wallace now alleges that he did entertain. But, be this as it may,
+we cannot expect to find in Darwin's writings any express allusion to a
+question which had not been raised until 1886. The most we can expect to
+find are scattered sentences which prove that the distinction in
+question was never so much as present to his mind,--i. e. never occurred
+to him as even a possible distinction.
+
+I will first take the passages which Mr. Wallace himself supplies from
+among those which I had previously indicated.
+
+     "But when, from the nature of the organism and of the conditions,
+     modifications have been induced which are unimportant for the
+     welfare of the _species_, they may be, and apparently often have
+     been, transmitted in nearly the same state to numerous, otherwise
+     modified, descendants[150]."
+
+    [150] _Origin of Species_, p. 175. Italics mine.
+
+On this passage Mr. Wallace remarks that the last five words "clearly
+show that such characters are usually not 'specific,' in the sense that
+they are such as distinguish species from one another, but are found in
+numerous allied species." But I cannot see that the passage shows
+anything of the sort. What to my mind it does show is, (_a_) that Mr.
+Darwin repudiated Mr. Wallace's doctrine touching the _necessary_
+utility of _all_ specific characters: (_b_) that he takes for granted
+the contrary doctrine touching the inutility of _some_ specific
+characters: (_c_) that without in this place alluding to the
+proportional number of useless specific characters, he refers their
+origin in some cases to "the nature of the organism" (i.e. "spontaneous
+variability" due to internal causes), and in other cases to "the
+conditions" (i.e. variability induced by external causes): (_d_) that
+when established as a specific character by heredity, such a useless
+character was held by him not to tend to become obsolete by the
+influence of natural selection or any other cause; but, on the contrary,
+to be "transmitted in nearly the same state to numerous, otherwise
+modified, descendants"--or progeny of the species in genera, families,
+&c.: (_e_) and, therefore, that useless characters which are now
+distinctive of genera, families, &c., were held by him frequently, if
+not usually, to point to uselessness of origin, when first they arose as
+merely specific characters. Even the meaning which Mr. Wallace reads
+into this passage must imply every one of these points; and therefore I
+do not see that he gains much by apparently seeking to add this further
+meaning--viz. that in Darwin's opinion there must have been some
+unassignable reason preventing the occurrence of useless specific
+characters in cases where species are _not_ destined to become the
+parents of genera.
+
+Moreover, any such meaning is out of accordance with the context from
+which the passage is taken. For, after a long consideration of the
+question of utility, Darwin sums up,--"We thus see that with plants many
+morphological changes may be attributed to the laws of growth and the
+interaction of parts, _independently of natural selection_." And then he
+adds,--"From the fact of the above characters being _unimportant for the
+welfare of the species_, any slight variations which occurred in them
+_would not have been augmented through natural selection_." Again, still
+within the same passage, he says, while alluding to the causes other
+than natural selection which lead to changes of specific
+characters,--"If the _unknown cause_ were to act almost uniformly for a
+length of time, we may infer that the result would be almost uniform;
+and in this case _all_ the individuals of the _species_ would be
+modified in the same manner." For my own part I do not understand how
+Mr. Wallace can have overlooked these various references to _species_,
+all of which occur on the very page from which he is quoting. The whole
+argument is to show that "many morphological changes may be attributed
+to the laws of growth and the inter-action of parts [_plus_ external
+conditions of life], independently of natural selection"; that such
+non-adaptive changes, when they occur as "specific characters," may, if
+the species should afterwards give rise to genera, families, &c., become
+distinctive of these higher divisions. But there is nothing here, or in
+any other part of Darwin's writings, to countenance the inconsistent
+notion which Mr. Wallace appears to entertain,--viz. that species which
+present useless characters are more apt to give rise to genera,
+families, &c., than are species which do not present such characters.
+
+The next passage which Mr. Wallace quotes, with his comments thereon, is
+as follows. The italics are his.
+
+     "'Thus a large yet undefined extension may safely be given to the
+     direct and indirect results of natural selection; but I now admit,
+     after reading the essay of Naegeli on plants, and the remarks by
+     various authors with respect to animals, more especially those
+     recently made by Professor Broca, that in the earlier editions of
+     my Origin of Species I perhaps attributed too much to the action of
+     natural selection, or the survival of the fittest. I have altered
+     the fifth edition of the Origin so as to confine my remarks to
+     adaptive changes of structure; _but I am convinced, from the light
+     gained during even the last few years, that very many structures
+     which now appear to be useless, will hereafter be proved to be
+     useful, and will therefore come within the range of natural
+     selection_. Nevertheless I did not formerly consider sufficiently
+     the existence of structures which, as far as we can at present
+     judge, are neither beneficial nor injurious; and this I believe to
+     be one of the greatest oversights as yet detected in my work.'
+
+     Now it is to be remarked that neither in these passages nor in any
+     of the other less distinct expressions of opinion on this question,
+     does Darwin ever admit that "specific characters"--that is, the
+     particular characters which serve to distinguish one species from
+     another--are ever useless, much less that "a large proportion of
+     them" are so, as Mr. Romanes makes him "freely acknowledge." On the
+     other hand, in the passage which I have italicised he strongly
+     expresses his view that much of what we suppose to be useless is
+     due to our ignorance; and as I hold myself that, as regards many of
+     the supposed useless characters, this is the true explanation, it
+     may be well to give a brief sketch of the progress of knowledge in
+     transferring characters from the one category to the other[151]."
+
+    [151] _Darwinism_, p. 132.
+
+It is needless to continue this quotation, because of course no one is
+disputing that an enormous number of specific characters whose utility
+is unknown are nevertheless useful, and therefore due to natural
+selection. In other words, the question is not--Are there not many
+useful specific characters whose utility is unknown? but--Does it follow
+from the theory of natural selection that all specific characters must
+necessarily be useful? Well, it appears to me that without going further
+than the above passage, which Mr. Wallace has quoted, we can see clearly
+enough what was Darwin's opinion upon the subject. He did not believe
+that it followed _deductively_ from his theory that all specific
+characters must necessarily be useful; and therefore he regarded it as a
+question of _fact_--to be determined by induction as distinguished from
+deduction--in what proportional number of cases they are so. Moreover he
+gives it as his more matured opinion, that, "as far as we can at present
+judge" (i.e. from the present state of observation upon the subject: if,
+with Mr. Wallace, his judgement were _a priori_, why this
+qualification?), he had not previously sufficiently considered the
+existence of non-adaptive characters--and this he ended by believing was
+one of the greatest oversights as yet detected in his work. To me it has
+always seemed that this passage is one of the greatest exhibitions of
+candour, combined with solidity of judgement, that is to be met with
+even in the writings of Darwin. There is no talk about any deductive
+"necessity"; but a perfect readiness to allow that causes other than
+natural selection may have been at work in evoking non-adaptive
+characters, so that the fifth edition of the _Origin of Species_ was
+altered in order to confine the theory of natural selection to "adaptive
+changes"--i.e. to constitute it, as I have said in other words, "a
+theory of the origin, or cumulative development, of _adaptations_."
+
+If to this it be said that in the above passage there is no special
+mention of _species_, the quibble would admit of a three-fold reply. In
+the first place, the quibble in question had never been raised. As
+already stated, it is only since the appearance of my own paper on
+_Physiological Selection_ that anybody ever thought of drawing a
+distinction between species and genera, such that while all specific
+characters must be held necessarily useful, no such necessity extends to
+generic characters. In the second place, that Darwin must have had
+specific characters (as well as generic) in his mind when writing the
+above passage, is rendered unquestionable by the fact that many of the
+instances of inutility adduced by Naegeli and Broca have reference to
+specific characters. Lastly, as shown in the passages previously quoted
+from the sixth edition of the _Origin of Species_, Darwin attributed the
+origin of useless generic characters to useless specific characters; so
+that Mr. Wallace really gains nothing by his remark that specific
+characters are not specially mentioned in the present passage.
+
+Once more:--
+
+     "Darwin's latest expression of opinion on this question is
+     interesting, since it shows he was inclined to return to his
+     earlier view of the general, or universal, utility of specific
+     characters[152]."
+
+    [152] _Darwinism_, p. 142.
+
+This "latest expression of opinion," as I shall immediately prove, shows
+nothing of the kind--being, in fact, a mere re-statement of the opinion
+everywhere and at all times expressed by Darwin, touching the caution
+that must be observed in deciding, _with respect to individual cases_,
+whether an apparently useless specific character is to be regarded as
+really useless. Moreover, at no time and in no place did Darwin
+entertain any "view of the general, or universal, utility of specific
+characters." But the point now is, that if (as was the case) Darwin
+"inclined" to depart more and more from his earlier view of the highly
+_general_ utility of specific characters; and if (as was not the case)
+he ended by showing an inclination "_to return_" to this earlier view;
+what becomes of the whole of Mr. Wallace's contention against which
+this Appendix is directed, namely, _that Darwin never entertained any
+other view than that of the "general, or universal, utility of specific
+characters_"?
+
+The "latest expression of opinion" which Mr. Wallace quotes, occurs in a
+letter written to Professor Semper in 1878. It is as follows:--
+
+     "As our knowledge advances, very slight differences, considered by
+     systematists as of no importance in structure, are continually
+     found to be functionally important; and I have been especially
+     struck with this fact in the case of plants, to which my
+     observations have of late years been confined. Therefore it seems
+     to me rather rash to consider the slight differences between
+     representative species, for instance those inhabiting the different
+     islands of the same archipelago, as of no functional importance,
+     and as not in any way due to natural selection[153]."
+
+    [153] _Life and Letters_, vol. iii. p. 161.
+
+Now, with regard to this passage it is to be observed, as already
+remarked, that it refers to the formation of final judgements touching
+_particular cases_: there is nothing to show that the writer is
+contemplating _general principles_, or advocating on deductive grounds
+the dogma that specific characters must be necessarily and universally
+adaptive characters. Therefore, what he here says is neither more nor
+less than I have said. For I have always held that it would be "rather
+rash" to conclude that any given cases of apparent inutility are
+certainly cases of real inutility, _merely on the ground that utility is
+not perceived_. But this is clearly quite a distinct matter from
+resisting the _a priori_ generalization that all cases of apparent
+inutility must certainly be cases of real utility. And, I maintain, in
+every part of his writings, without any exception, where Darwin alludes
+to this matter of general principle, it is in terms which directly
+contradict the deduction in question. As the whole of this Appendix has
+been directed to proving that such is the case, it will now, I think, be
+sufficient to supply but one further quotation, in order to show that
+the above "latest expression of opinion," far from indicating that in
+his later years Darwin "inclined" to Mr. Wallace's views upon this
+matter, is quite compatible with a distinct "expression of opinion" to
+the contrary, in a letter written less than six years before his death.
+
+     "In my opinion _the greatest error which I have committed_, has
+     been not allowing sufficient weight to the direct action of the
+     environment, i.e. food, climate, &c., _independently of natural
+     selection_. Modifications thus caused, _which are neither of
+     advantage nor disadvantage to the modified organisms_, would be
+     especially favoured, as I can now see chiefly through your
+     observations, _by isolation in a small area, where only a few
+     individuals lived under nearly uniform conditions_[154]."
+
+    [154] _Life and Letters_, vol. iii. p. 158.
+
+I will now proceed to quote further passages from Darwin's works, which
+appear to have escaped the notice of Mr. Wallace, inasmuch as they admit
+of no doubt regarding the allusions being to _specific_ characters.
+
+     "_We may easily err in attributing importance to characters, and in
+     believing that they have been developed through natural selection._
+     We must by no means overlook the effects of the definite action of
+     changed conditions of life,--of so-called spontaneous variations,
+     which seem to depend in a quite subordinate degree on the nature of
+     the conditions,--of the tendency to reversion to long-lost
+     characters,--of the complex laws of growth, such as of
+     correlation[155], compensation, of pressure of one part on another,
+     &c., and finally of sexual selection, by which characters of use to
+     one sex are often gained and then transmitted more or less
+     perfectly to the other sex, though of no use to this sex. But
+     structures thus indirectly gained, _although at first of no
+     advantage to a species_, may subsequently have been taken advantage
+     of by its modified descendants, under new conditions of life and
+     newly acquired habits[156]."
+
+    [155] It must be observed that Darwin uses this word, not as Mr.
+          Wallace always uses it (viz. as if correlation can only be
+          with regard to adaptive characters), but in the wider sense
+          that any change in one part of an organism--whether or not it
+          happens to be an adaptive change--is apt to induce changes in
+          other parts.
+
+    [156] _Origin of Species_, pp. 157-8.
+
+It appeared--and still appears--to me, that where so many causes are
+expressly assigned as producing useless _specific_ characters, and that
+some of them (such as climatic influences and independent variability)
+must be highly general in their action, I was justified in representing
+it as Darwin's opinion that "a large proportional number of specific
+characters" are useless to the _species_ presenting them, although
+afterwards they may sometimes become of use to genera, families, &c.
+Moreover, this passage goes on to point out that specific characters
+which at first sight appear to be obviously useful, are sometimes found
+by fuller knowledge to be really useless--a consideration which is the
+exact inverse of the argument from ignorance as used by Mr. Wallace, and
+serves still further to show that in Darwin's opinion utility is by no
+means an invariable, still less a "necessary," mark of specific
+character. The following are some of the instances which he gives.
+
+     "The sutures in the skulls of young mammals have been advanced as a
+     beautiful adaptation for aiding parturition, and no doubt they may
+     facilitate, or be indispensable for this act; but as sutures occur
+     in the skulls of young birds and reptiles, which have only to
+     escape from a broken egg, we may infer that this structure has
+     _arisen from the laws of growth_, and has been taken advantage of
+     in the parturition of the higher animals[157]."
+
+     "The naked skin on the head of a vulture is generally considered as
+     a direct adaptation for wallowing in putridity; and so it may be,
+     _or it may possibly be due to the direct action of the putrid
+     matter_; but we should be very cautious in drawing any such
+     inference [i.e. as to utility] when we see the skin on the head of
+     the clean-feeding male Turkey is likewise naked[158]."
+
+    [157] _Ibid._
+
+    [158] _Origin of Species_, pp. 157-8.
+
+Similarly, in the _Descent of Man_ it is said:--
+
+     "Variations of the same _general_ nature have _often been taken
+     advantage of_ and accumulated through sexual selection in relation
+     to the propagation of the species, and through natural selection in
+     relation to the general purposes of life. Hence, _secondary sexual
+     characters, when equally transmitted to both sexes, can be
+     distinguished from ordinary specific characters, only by the light
+     of analogy_. The modifications acquired through sexual selection
+     are often so strongly pronounced that the two sexes have frequently
+     been ranked as distinct species, or even as distinct genera[159]."
+
+    [159] _Descent of Man_, p. 615.
+
+As Mr. Wallace does not recognize sexual selection, he incurs the burden
+of proving utility (in the life-preserving sense) in all these
+"frequently" occurring cases where there are such "strongly pronounced
+modifications," and we have already seen in the text his manner of
+dealing with this burden. But the point here is, that whether or not we
+accept the theory of sexual selection, we must accept it as Darwin's
+opinion--first, that in their beginnings, as _specific_ characters,
+these sexual modifications were often of a merely "_general nature_" (or
+without reference to utility even in the life-embellishing sense), and
+only _afterwards_ "have often been taken advantage of and accumulated
+through _sexual_ selection": and, secondly, that "we know they have been
+acquired in some instances _at the cost not only of inconvenience, but
+of exposure to actual dangers_[160]."
+
+    [160] _Ibid._
+
+We may now pass on to some further, and even stronger, expressions of
+opinion with regard to the frequent inutility of _specific_ characters.
+
+     "I have made these remarks only to show that, if we are unable to
+     account for the characteristic differences of our several domestic
+     breeds, which nevertheless are generally admitted to have arisen
+     through ordinary generation from one or a few parent stocks, we
+     ought not to lay too much stress on our ignorance of the precise
+     cause [i.e. whether natural selection or some other cause] of the
+     slight analogous differences between true _species_.... I fully
+     admit that _many_ structures are now of no use to their possessors,
+     and may never have been of any use to their progenitors; but this
+     does not prove that they were formed solely for beauty or variety.
+     No doubt the definite action of changed conditions, and the various
+     causes of modification, lately specified, have all produced an
+     effect, _probably a great effect, independently of any advantage
+     thus gained_.... It is scarcely possible to decide how much
+     allowance ought to be made for such causes of change, as the
+     definite action of external conditions, so-called spontaneous
+     variations, and the complex laws of growth; but, _with these
+     important exceptions_, we may conclude that the structure of every
+     living creature either now is, or formerly was, of some direct or
+     indirect use to its possessor[161]."
+
+    [161] _Descent of Man_, pp. 159-60.
+
+Here again, if we remember how "important" these "exceptions" are, I
+cannot understand any one doubting Darwin's opinion to have been that a
+large proportional number of specific characters are useless. For that
+it is "species" which he here has mainly in his mind is evident from
+what he says when again alluding to the subject in his "Summary of the
+Chapter"--namely, "In _many_ other cases [i.e. in cases where natural
+selection has not been concerned] modifications are probably the direct
+result of the laws of variation or of growth, independently of any good
+having been thus gained." Now, not only do these "laws" apply as much to
+species as they do to genera; "but," the passage goes on to say, "even
+such structures have often, we may feel assured, been subsequently
+taken advantage of, and still further modified, for the good of
+_species_ under new conditions of life." Obviously, therefore, the
+inutility in such cases is taken to have been prior to any utility
+subsequently acquired; and genera are not historically prior to the
+species in which they originate.
+
+Here is another quotation:--
+
+     "Thus, as I am inclined to believe, morphological differences,
+     which we consider as important--such as the arrangement of the
+     leaves, the divisions of the flower or of the ovarium, the position
+     of the ovules, &c.--_first_ appeared in _many_ cases as
+     _fluctuating variations_, which sooner or later became constant
+     through the nature of the organism and of the surrounding
+     conditions, as well as through the intercrossing of distinct
+     individuals, _but not through natural selection_; for as these
+     morphological characters do not affect the welfare of the
+     _species_, any slight deviations in them could not have been
+     governed or accumulated through this latter agency. It is a strange
+     result which we thus arrive at, namely, that characters of slight
+     vital importance to the _species_, are the most important to the
+     systematist; but, as we shall hereafter see when we treat of the
+     genetic principle of classification, this is by no means so
+     paradoxical as it may at first appear[162]."
+
+    [162] _Descent of Man_, p. 176.
+
+Clearly the view here expressed is that characters which are now
+distinctive of higher taxonomic divisions "first appeared" in the parent
+species of such divisions; for not only would it be unreasonable to
+attribute the rise and preservation of useless characters to
+"fluctuating variations" affecting a number of species or genera
+similarly and simultaneously; but it would be impossible that, if such
+were the case, they could be rendered "constant through the nature of
+the organism and of the surrounding conditions, as well as through the
+intercrossing of distinct individuals[163]."
+
+    [163] The passage to which these remarks apply is likewise quoted,
+          in the same connexion as above, in my paper on _Physiological
+          Selection_. In criticising that paper in _Nature_ (vol. xxxix.
+          p. 127), Mr. Thiselton Dyer says of my interpretation of this
+          passage, "the obvious drift of this does not relate to
+          specific differences, but to those which are characteristic of
+          family." But in making this remark Mr. Dyer could not have
+          read the passage with sufficient care to note the points which
+          I have now explained.
+
+Here is another passage to the same general effect. In alluding to the
+objection from inutility as advanced by Bronn, Broca, and Naegeli, Mr.
+Darwin says:--"There is much force in the above objection"; and, after
+again pointing out the important possibility in any particular cases of
+hidden or former use, and the action of the laws of growth, he goes on
+to say,--"In the third place, we have to allow for the direct and
+definite action of changed conditions of life, and for so-called
+spontaneous variations, in which the nature of the conditions plays
+quite a subordinate part[164]." Elsewhere he says,--"It appears that I
+formerly underrated the frequency and value of these latter forms of
+variation as leading to permanent modifications of structure
+_independently of natural selection_[165]." The "forms of variation" to
+which he here alludes are "variations which seem to us in our ignorance
+to arise spontaneously"; and it is evident that such variations cannot
+well "arise" in two or more species of a genus similarly and
+simultaneously, so as independently to lead "to permanent modifications
+of structure" in two or more parallel lines. It is further evident that
+by "spontaneous variations" Darwin alludes to extreme cases of
+spontaneous departure from the general average of specific characters;
+and therefore that lesser or more ordinary departures must be of still
+greater "frequency."
+
+    [164] _Origin of Species_, p. 171.
+
+    [165] _Ibid._ p. 421.
+
+Again, speaking of the principles of classification, Darwin writes:--
+
+     "We care not how trifling a character may be--let it be the mere
+     inflection of the angle of the jaw, the manner in which an
+     insect's wing is folded, whether the skin be covered by hair or
+     feathers--if it prevail throughout many and different species,
+     especially those having very different habits of life, it assumes
+     high value [i.e. for purposes of classification]; for we can
+     account for its presence in so many forms with such _different
+     habits_, only by inheritance from a common parent. We may err in
+     this respect in regard to single points of structure, but when
+     several characters, let them be ever so trifling, concur throughout
+     a large group of beings _having different habits_, we may feel
+     almost sure, on the theory of descent, that these characters have
+     been inherited from a common ancestor; and we know that such
+     aggregated characters have especial value in classification[166]."
+
+    [166] _Origin of Species_, pp. 372-373.
+
+Now it is evident that this argument for the general theory of evolution
+would be destroyed, if Wallace's assumption of utility of specific
+characters as universal were to be entertained. And the fact of
+apparently "trifling" characters occurring throughout a large group of
+beings "having different habits" is proof that they are really trifling,
+or without utilitarian significance.
+
+It is needless to multiply these quotations, for it appears to me that
+the above are amply sufficient to establish the only point with which we
+are here concerned, namely, that Darwin's opinion on the subject of
+utility in relation to specific characters was substantially identical
+with my own. And this is established, not merely by the literal meaning
+of the sundry passages here gathered together from different parts of
+his writings; but likewise, and perhaps still more, from the tone of
+thought which pervades these writings as a whole. It requires no words
+of mine to show that the literal meaning of the above quotations is
+entirely opposed to Mr. Wallace's view touching the _necessary_ utility
+of _all_ specific characters; but upon the other point--or the general
+tone of Mr. Darwin's thought regarding such topics--it may be well to
+add two remarks.
+
+In the first place, it must be evident that so soon as we cease to be
+bound by any _a priori_ deduction as to natural selection being "the
+exclusive means of modifications," it ceases to be a matter of much
+concern to the theory of natural selection in what proportion other
+means of modification have been at work--especially when non-adaptive
+modifications are concerned, and where these have reference to merely
+"specific characters," or modifications of the most incipient kind,
+least generally diffused among organic types, and representing the
+incidence of causes of less importance than any others in the process of
+organic evolution considered as a whole. Consequently, in the second
+place, we find that Darwin nowhere displays any solicitude touching the
+proportional number of specific characters that may eventually prove to
+be due to causes other than natural selection. He takes a much wider and
+deeper view of organic evolution, and, having entirely emancipated
+himself from the former conception of species as the organic units, sees
+virtually no significance in specific characters, except in so far as
+they are also adaptive characters.
+
+Such, at all events, appears to me the obvious interpretation of his
+writings when these are carefully read with a view to ascertaining his
+ideas upon "Utilitarian doctrine: how far true." And I make these
+remarks because it has been laid to my charge, that in quoting such
+passages as the above I have been putting "a strained interpretation"
+upon Darwin's utterances: "such admissions," it is said, "Mr. Romanes
+appears to me to treat as if wrung from a hostile witness[167]." But,
+from what has gone before, it ought to be apparent that I take precisely
+the opposite view to that here imputed. Far from deeming these and
+similar passages as "admissions wrung from a hostile witness," and far
+from seeking to put any "strained interpretation" upon them, I believe
+that they are but the plain and unequivocal expressions of an opinion
+which I have always understood that Darwin held. And if any one has been
+led to think otherwise, I throw back this charge of "strained
+interpretation," by challenging such a person to adduce a single
+quotation from any part of Darwin's works, which can possibly be held to
+indicate that he regarded passages like those above quoted as in any way
+out of conformity with his theory of natural selection--or as put
+forward merely to "admit the possibility of explanations, to which
+really, however, he did not attach much importance." To the best of my
+judgement it is only some bias in favour of Mr. Wallace's views that can
+lead a naturalist to view in this way the clear and consistent
+expression of Darwin's.
+
+    [167] Mr. Thiselton Dyer in _Nature_, _loc. cit._
+
+That Mr. Wallace himself should be biassed in this matter might,
+perhaps, be expected. After rendering the following very unequivocal
+passage from the _Origin of Species_ (p. 72)--"There can be little doubt
+that the tendency to vary in the same manner has often been so strong,
+_that all individuals of the same species have been similarly modified
+without the aid of any form of selection_"--Mr. Wallace says, "But no
+proof whatever is offered of this statement, and it is so entirely
+opposed to all we know of the facts of variation as given by Darwin
+himself, that the important word 'all' is probably an oversight." But,
+if Mr. Wallace had read the very next sentence he would have seen that
+here the important word "all" could not _possibly_ have been "an
+oversight." For the passage continues,--"Or only a third, fifth, or
+tenth part of the individuals may have been thus affected, of which fact
+several instances could be given. Thus Graba estimates that about
+one-fifth of the guillemots in the Faroe Islands consist of a variety so
+well marked, that it was formerly ranked as a distinct species under the
+name of Uria lacrymans." And even if this passage had not been thus
+specially concerned with the question of the _proportion_ in which
+"_individuals of the same species have been similarly modified without
+the aid of any form of selection_" the oversight with respect to "the
+important word 'all'" would still have remained an oversight of a
+recurrent character, as the following additional quotations from other
+parts of Darwin's writings may perhaps render apparent.
+
+     "There must be some efficient cause for each slight individual
+     difference, as well as for more strongly marked variations which
+     occasionally arise; and if the unknown cause were to act
+     persistently, it is almost certain that _all_ the individuals of
+     the _species_ would be similarly modified[168]."
+
+     "The acquisition of a useless part can hardly be said to raise an
+     organism in the natural scale.... We are so ignorant of the
+     exciting cause of the above specified modifications; but if the
+     unknown cause were to act almost uniformly for a length of time, we
+     may infer that the result would be almost uniform; and in this case
+     _all_ the individuals of the _species_ would be modified in the
+     same manner[169]."
+
+    [168] _Origin of Species_, p. 171.
+
+    [169] _Ibid._ p. 175.
+
+Moreover, when dealing even with such comparatively slight changes as
+occur between our domesticated varieties--and which, _a fortiori_, are
+less likely to become "stable" through the uniform operation of causes
+other than selection, seeing that they are not only smaller in amount
+than occurs among natural species, but also have had but a comparatively
+short time in which to accumulate--Darwin is emphatic in his assertion
+of the same principles. For instance, in the twenty-third chapter of the
+_Variation of Plants and Animals under Domestication_, he repeatedly
+uses the term "definite action of external conditions," and begins the
+chapter by explaining his use of the term thus:--
+
+     "By the term definite action, as used in this chapter, I mean an
+     action of such a nature that, when many individuals of the same
+     variety are exposed during several generations to any change in
+     their physical conditions of life, _all_, or _nearly all_, the
+     individuals are modified in the same manner. A new _sub-variety_
+     would thus be produced _without the aid of selection_[170]."
+
+    [170] _Variation_, &c., vol. ii. p. 260.
+
+As an example of the special instances that he gives, I may quote the
+following from the same work:--
+
+     "Each of the endless variations which we see in the plumage of our
+     fowls must have had some efficient cause; and if the same cause
+     were to act uniformly during a long series of generations on many
+     individuals, _all_ probably would be modified in the same manner."
+
+And, as instances of his more general statements in Chapter XXIII, these
+may suffice:--
+
+     "The direct action of the conditions of life, whether leading to
+     definite or indefinite results, _is a totally distinct
+     consideration from the effects of natural selection_.... The direct
+     and definite action of changed conditions, in contradistinction to
+     the accumulation of indefinite variations, _seems to me so
+     important_ that I will give a large additional body of
+     miscellaneous facts[171]."
+
+    [171] _Ibid._ vol. ii. p. 261.
+
+Then, after giving these facts, and showing how in the case of species
+in a state of nature it is often impossible to decide how much we are to
+attribute to natural selection and how much to the definite action of
+changed conditions, he begins his general summary of the chapter thus:--
+
+     "There can be no doubt, from the facts given in the early part of
+     this chapter, that extremely slight changes in the conditions of
+     life sometimes act in a definite manner on our already variable
+     domesticated productions [productions, therefore, with regard to
+     which uniformity and 'stability' of modification are least likely
+     to arise]; and, as the action Of changed conditions in causing
+     general or indefinite variability is accumulative, so it may be
+     with their definite action. Hence it is possible that _great_ and
+     _definite_ modifications of structure may result from altered
+     conditions acting during a long series of generations. In some few
+     instances a marked effect has been produced quickly on _all_, or
+     _nearly all_, the individuals which have been exposed to some
+     considerable change of climate, food, or other circumstance[172]."
+
+    [172] _Variation_, &c., vol. ii. p. 280.
+
+Once more, in order to show that he retained these views to the end of
+his life, I may quote a passage from the second edition of the _Descent
+of Man_, which is the latest expression of his opinion upon these
+points:--
+
+     "Each of the endless diversities in plumage, which we see in our
+     domesticated birds, is, of course, the result of some definite
+     cause; and under natural and more uniform conditions, some one
+     tint, _assuming that it was in no way injurious, would almost
+     certainly sooner or later prevail_. The free-intercrossing of the
+     many individuals belonging to the same species would ultimately
+     tend to make any change of colour thus induced _uniform in
+     character_.... Can we believe that the very slight differences in
+     tints and markings between, for instance, the female black-grouse
+     and red-grouse serve as a protection? Are partridges as they are
+     now coloured, better protected than if they had resembled quails?
+     Do the slight differences between the females of the common
+     pheasant, the Japan and golden pheasants, serve as a protection, or
+     might not their plumage have been interchanged with impunity? From
+     what Mr. Wallace has observed of the habits of certain gallinaceous
+     birds in the East, he thinks that such slight differences are
+     beneficial. For myself, I will only say, I am not convinced[173]."
+
+    [173] _Descent of Man_, pp. 473-4.
+
+Yet "convinced" he certainly must have been on merely _a priori_
+grounds, had he countenanced Mr. Wallace's reasoning from the general
+theory of natural selection; and the fact that he here fails to be
+convinced even by "what Mr. Wallace has observed of the habits of
+certain gallinaceous birds," appears to indicate that he had considered
+the question of utility with special reference to Mr. Wallace's opinion.
+That opinion was then, as now, the avowed result of a theoretical
+prepossession; and this prepossession, as the above quotations
+sufficiently show, was expressly repudiated by Darwin.
+
+Lastly, this is not the only occasion on which Darwin expressly
+repudiates Mr. Wallace's opinion on the point in question. For it is
+notorious that these co-authors of the theory of natural selection have
+expressed divergent opinions concerning the origin by natural selection
+of the most general of all specific characters--cross-sterility.
+Although allowing that cross-sterility between allied species may be of
+adaptive value in "keeping incipient species from blending," Darwin
+persistently refused to be influenced by Wallace's belief that it is due
+to natural selection; i.e. the belief on which alone can be founded the
+"necessary deduction" with which we have been throughout concerned.
+
+
+
+
+NOTE A TO PAGE 57.
+
+
+I think it is desirable here to adduce one or two concrete illustrations
+of these abstract principles, in order to show how, as a matter of fact,
+the structure of Weismann's theory is such as to preclude the
+possibility of its assumptions being disproved--and this even supposing
+that the theory is false.
+
+At first sight nothing could seem more conclusive on the side of
+Darwinian or Lamarckian principles than are the facts of hereditary
+disease, in cases where the disease has unquestionably been acquired by
+the parents. Take, for example, the case of gout. Here there is no
+suspicion of any microbe being concerned, nor is there any question
+about the fact of the disease being one which is frequently acquired by
+certain habits of life. Now, suppose the case of a man who in middle age
+acquires the gout by these habits of life--such as insufficient
+exercise, over-sufficient food, and free indulgence in wine. His son
+inherits the gouty diathesis, and even though the boy may have the fear
+of gout before his eyes, and consequently avoid over-eating and
+alcoholic drinking, &c., the disease may overtake him also. Well, the
+natural explanation of all this is, that the sins of the fathers descend
+upon the children; that gout acquired may become in the next generation
+gout transmitted. But, on the other hand, the school of Weismann will
+maintain that the reason why the parent contracted the gout was because
+he had a congenital, or "blastogenetic," tendency towards that
+disease--a tendency which may, indeed, have been intensified by his
+habits of life, but which, in so far as thus intensified, was not
+transmitted to his offspring. All that was so transmitted was the
+congenital tendency; and all that is proved by such cases as those above
+supposed, where the offspring of gouty parents become gouty
+notwithstanding their abstemious habits, is that in such offspring the
+congenital tendency is even more pronounced than it was in their
+parents, and therefore did not require so much inducement in the way of
+unguarded living to bring it out. Now, here again, without waiting to
+consider the relative probabilities of these two opposing explanations,
+it is enough for the purposes of the illustration to remark that it is
+obviously impossible to disprove either by means of the other, or by any
+class of facts to which they may severally appeal.
+
+I will give only one further example to show the elusiveness of
+Weismann's theory, and the consequent impossibility of finding any cases
+in nature which will satisfy the conditions of proof which the theory
+imposes. In one of his papers Weismann says that if there be any truth
+in the Lamarckian doctrine of the transmission of acquired characters,
+it ought to follow that the human infant should speak by instinct. For,
+ever since man became human he has presumably been a talking animal: at
+any rate it is certain that he has been so for an innumerable number of
+generations. Therefore, by this time the faculty of language ought to
+have been so deeply impressed upon the psychology of the species, that
+there ought to be no need to teach the young child its use of language;
+and the fact that there is such need is taken by Weismann to constitute
+good evidence in proof of the non-transmissibility of individually
+acquired characters. Or, to quote his own words, "it has never yet been
+found that a child could read of itself, although its parents had
+throughout their whole lives practised this art. Not even are our
+children able to talk of their own accord; yet not only have their
+parents, but, more than that, an infinitely long line of ancestors have
+never ceased to drill their brains and to perfect their organs of
+speech.... From this alone we may be disposed to doubt whether acquired
+capabilities in the true sense can ever be transmitted." Well, in answer
+to this particular case, we have first of all to remark that the
+construction of even the simplest language is, psychologically
+considered, a matter of such enormous complexity, that there is no real
+analogy between it and the phenomena of instinct: therefore the fact
+that Lamarckian principles cannot be applied to the case of language is
+no evidence that they do not hold good as regards instinct. Secondly,
+not only the construction, but still more the use of language is quite
+out of analogy with all the phenomena of instinct; for, in order to use,
+or speak, a language, the mind must already be that of a thinking agent;
+and therefore to expect that language should be instinctive is
+tantamount to expecting that the thought of which it is the vehicle
+should be instinctive--i.e. that human parents should transmit the whole
+organization of their own intellectual experiences to their unborn
+children. Thirdly, even neglecting these considerations, we have to
+remember that language has been itself the product of an immensely long
+course of evolution; so that even if it were reasonable to expect that a
+child should speak by instinct without instruction, it would be
+necessary further to expect that the child should begin by speaking in
+some score or two of unknown tongues before it arrived at the one which
+alone its parents could understand. Probably these considerations are
+enough to show how absurd is the suggestion that Darwinians ought to
+expect children to speak by instinct. But, now, although it is for these
+reasons preposterous under any theory of evolution to expect that
+children should be able to use a fully developed language without
+instruction, it is by no means so preposterous to expect that, if all
+languages present any one simple set of features in common, these
+features might by this time have grown to be instinctive; for these
+simple features, being common to all languages, must have been
+constantly and forcibly impressed upon the structure of human psychology
+throughout an innumerable number of sequent generations. Now, there is
+only one set of features common to all languages; and this comprises the
+combinations of vowel and consonantal sounds, which go to constitute
+what we know as articulate syllables. And, is it not the case that these
+particular features, thus common to all languages, as a matter of fact
+actually _are_ instinctive? Long before a young child is able to
+understand the meanings of any words, it begins to babble articulate
+syllables; and I do not know that a more striking fact can be adduced at
+the present stage of the Weismann controversy than is this fact which he
+has thus himself unconsciously suggested, namely, that the young of the
+only talking animal should be alone in presenting--and in unmistakably
+presenting--the instinct of articulation. Well, such being the state of
+matters as regards this particular case, in the course of a debate which
+was held at the Newcastle meeting of the British Association upon the
+heredity question, I presented this case as I present it now. And
+subsequently I was met, as I expected to be met, by its being said that
+after all the faculty of making articulate sounds might have been of
+congenital origin. Seeing of how much importance this faculty must
+always have been to the human species, it may very well have been a
+faculty which early fell under the sway of natural selection, and so it
+may have become congenital. Now, be it remembered, I am only adducing
+this case in illustration of the elusiveness of Weismann's theory. First
+of all he selects the faculty of articulate speech to argue that it is a
+faculty which ought to be instinctive if acquired characters ever do
+become instinctive; and so good does he deem it as a test case between
+the two theories, that he says _from it alone_ we should be prepared to
+accept the doctrine that acquired characters can never become
+congenital. Then, when it is shown that the only element in articulate
+speech which possibly could have become congenital, actually has become
+congenital, the answer we receive is a direct contradiction of the
+previous argument: the faculty originally selected as representative of
+an acquired character is now taken as representative of a congenital
+one. By thus playing fast and loose with whatever facts the followers of
+Darwin may adduce, the followers of Weismann bring their own position
+simply to this:--All characters which can be shown to be inherited we
+assume to be congenital, or as we term it, "blastogenetic," while all
+characters which can be shown not to be inherited, we assume to be
+acquired, or as we term it, "somatogenetic"--and this merely on the
+ground that they have been shown to be inherited or not inherited as the
+case may be. Now, there need be no objection to such assumptions,
+provided they are recognized as assumptions; but so long as the very
+question in debate has reference to their validity as assumptions, it is
+closely illogical to adduce them as arguments. And this is the only
+point with which we are at present concerned.
+
+
+
+
+NOTE B TO PAGE 89.
+
+
+In answer to this illustration as previously adduced by me, Mr. Poulton
+has objected that the benefit arising from the peculiar mode of stinging
+in question is a benefit conferred, not on the insect which stings, but
+upon its progeny. The point of the illustration however has no reference
+to the maternal instinct (which here, as elsewhere, I doubt not is due
+to natural selection); it has reference only to the particular instinct
+of selective stinging, which here ministers to the purposes of the other
+and more general instinct of rearing progeny. Given then the maternal
+instinct of stinging prey for the use of progeny, the question is--What
+first determined the ancestors of the Sphex to sting their prey only in
+nine particular points? Darwin's answer to this question is as
+follows:--
+
+     "I have been thinking about Pompilius and its allies. Please take
+     the trouble to read on perforation of the corolla by Bees, p. 425
+     of my 'Cross-fertilization,' to end of chapter. Bees show so much
+     intelligence in their acts, that it seems not improbable to me that
+     the progenitors of Pompilius originally stung caterpillars and
+     spiders, &c., in any part of their bodies, and then observed by
+     their intelligence that if they stung them in one particular place,
+     as between certain segments on the lower side, their prey was at
+     once paralyzed. It does, not seem to me at all incredible that this
+     action should then become instinctive, i.e. memory transmitted from
+     one generation to another. It does not seem necessary to suppose
+     that when Pompilius stung its prey in the ganglion it intended or
+     knew that their prey would keep long alive. The development of the
+     larvae may have been subsequently modified in relation to their
+     half-dead, instead of wholly dead prey; supposing that the prey was
+     at first quite killed, which would have required much stinging.
+     Turn this over in your mind," &c.
+
+Weismann, on the other hand, can only suppose that this intensely
+specialized instinct had its origin in fortuitous variations in the
+psychology of the species. But, neglecting the consideration that, in
+order to become fixed as an instinct by natural selection, the
+particular variation required must have occurred in many different
+individuals, not only in the first, but also in the sequent generations,
+the chances against its occurring only once, or in but one single
+individual case, are many thousands if not millions to one.
+
+
+
+
+INDEX
+
+
+A.
+
+Acceleration and retardation, 16.
+
+Acquired characters, heredity of, 39, 103, 133.
+
+Adaptation, 7, 13, 55, 62, 67, 71, 159, 165;
+  of species and of specific characters, 166.
+
+ALLEN, Mr., referred to, 209.
+
+_All-sufficiency of Natural Selection_, referred to, 65, 95.
+
+_Alone with the Hairy Ainu_, referred to, 26.
+
+American and European trees compared, 201.
+
+_American Journal of Science_, referred to, 273.
+
+_American Naturalist_, referred to, 35, 58.
+
+Ammonites, species of, 254.
+
+_Animal Intelligence_, referred to, 93.
+
+_Animal Life_, referred to, 101.
+
+_Animal Life and Intelligence_, referred to, 33, 36.
+
+_Apparent Paradox in Mental Evolution_, referred to, 90.
+
+Appendages of Normandy and Irish pigs, 188.
+
+Articulation and inheritance, 335.
+
+Artistic faculties of man, 27.
+
+
+B.
+
+BABINGTON, Prof., referred to, 252.
+
+BACHMAN, Dr., referred to, 186.
+
+BAILEY, Prof., referred to, 127.
+
+BAKER, Mr., referred to, 252.
+
+Balancing of brainless frog, 78.
+
+BALL, Mr. Platt, referred to, 3, 95; quoted, 50.
+
+BATESON, Mr. W., referred to, 36.
+
+BEDDARD, Mr. F., referred to, 174.
+
+BENTHAM, Mr., referred to, 252.
+
+Birds, diagnostic characters of, 176;
+  of Australia, effect of climate on, 210;
+  influence of food on, 218.
+
+Blastogenetic, 123, 242, 245, 250.
+
+Blending of adaptations, 67.
+
+_Brain_, referred to, 80.
+
+BROCA, Prof., referred to, 64, 67, 174, 318.
+
+BRONN, Prof., referred to, 174.
+
+BROOKS, Prof., referred to, 14.
+
+BROWN-SEQUARD, referred to, 104, 122, 142; quoted, 104.
+
+BUCKLEY, Mr., referred to, 147.
+
+BUCKMAN, Prof. James, referred to, 125.
+
+BUCKMAN, Prof. S.S., referred to, 24.
+
+BUTLER, Mr. A. G., referred to, 254.
+
+BUTLER, Mr. Samuel, referred to, 87.
+
+Butterfly, seasonal changes of, 210;
+  influence of food on, 217.
+
+
+C.
+
+Carnivora, instincts of, 89.
+
+CARRIERE, M. L. A., referred to, 123.
+
+Cave animals, colour-changes in, 211.
+
+_Cave Fauna of North America_, quoted, 211.
+
+Cessation of Selection, 99, 199, 212, 292.
+
+Characters, adaptive and specific, 159, 307;
+  specific, due to Natural Selection, 171.
+
+_Charadriidae, Geographical Distribution of the Family_, quoted, 173.
+
+Chimpanzee, counting of, 31.
+
+Climate, influence of, on plants, 200;
+  on animals, 209.
+
+Co-adaptation, 64.
+
+COCKERELL, Prof., referred to, 218.
+
+Colour, 269.
+
+Colour-changes in butterflies, 210.
+  in cave animals, 211.
+
+_Colours of Animals_, referred to, 36.
+
+Congenital, as opposed to acquired characters, 134.
+
+Constancy of characters not necessarily due to Natural Selection, 186.
+
+_Contemporary Review_, referred to, 60, 65, 95
+
+Continuity of germ-plasm, 44, 61, 133;
+  absolute and relative, 134, 155.
+
+_Contributions to the Theory of Natural Selection_, referred to, 2;
+quoted, 180.
+
+COPE, Prof., referred to, 14, 15, 20, 63, 256; quoted, 16.
+
+Correlation, 171, 184, 211, 222, 268.
+
+COSTA, M., quoted, 217.
+
+CUNNINGHAM, Mr. J. T., quoted, 103; referred to, 95, 122.
+
+
+D.
+
+DALL, Prof., referred to, 14.
+
+DARWIN, Charles, referred to, 1-13, 20-22, 25, 44, 45, 51-53, 56, 66,
+67, 74, 87, 88, 93, 95, 96-100, 149, 159, 160, 167, 173, 174, 181-183,
+187-191, 193, 195, 198, 200-202, 213-216, 218, 219, 226, 256, 261-265,
+268, 271, 277, 283, 287, 291, 305-307, 313-332, 337; quoted, 11, 53, 66,
+96, 181, 182, 186-191, 193, 195, 201, 202, 213-215, 261, 262, 265,
+313-316, 319-322, 324-326, 328-331, 337.
+
+_Darwin et ses Precurseurs Francais_, referred to, 234.
+
+_Darwinian Theory of the Origin of Species_, quoted, 254.
+
+_Darwinism_, quoted, 22, 27, 67, 181, 182, 186, 189-191, 221, 222, 235,
+236, 252, 253, 269, 270, 273, 313, 316; referred to, 7, 12, 15, 20, 70.
+
+DE CANDOLLE, Prof., referred to, 206.
+
+Deep-sea faunas, 212.
+
+DELB[OE]UF, referred to, 224.
+
+_Descent of Man_, quoted, 25, 322-324, 331.
+
+_Development of the Hard Parts of the Mammalia_, referred to, 14.
+
+DE VRIES, Prof., referred to, 122, 174.
+
+Diagnostic characters of birds, 176;
+  Marsupials, 178.
+
+Divergent Evolution through Cumulative Segregation, quoted, 224.
+
+DIXON, Mr. Charles, referred to, 174; quoted, 177, 223.
+
+_Doctrine of Descent and Darwinism_, quoted, 260.
+
+Dogs, scratching, reflex of, 80;
+  shaking off water, 84;
+  transplantation of ovaries, 143.
+
+DORFMEISTER, Dr., referred to, 211.
+
+Ducks, use-inheritance in, 96;
+  losing true plumage, 187.
+
+DUPUY, Dr., referred to, 105.
+
+DYER, Mr. Thistleton, quoted, 325, 327.
+
+
+E.
+
+_Effect of External Influences upon Development_, referred to, 66, 95.
+
+_Effects of Use and Disuse_, quoted, 50.
+
+EIMER, Prof., referred to, 14, 174, 217.
+
+_Entomological Society, Trans. of_, quoted, 211; referred to, 217.
+
+Epilepsy of guinea-pigs, 104.
+
+_Essays on Heredity_, quoted, 56, 91, 97, 107, 152; referred to, 12, 36,
+65, 105, 110.
+
+EUDES-DESLONGCHAMPS, M., referred to, 188.
+
+European and American trees, compared, 201.
+
+EVEREST, Rev. E., quoted, 213.
+
+_Evolution without Natural Selection_, quoted, 177.
+
+_Examination of Weismannism_, referred to, 39-42, 44, 100, 122, 123,
+134, 136, 138-140, 156.
+
+_Experiments in Pangenesis_, referred to, 145.
+
+
+F.
+
+FABRE, M., referred to, 88.
+
+Factors of organic evolution:
+  Natural Selection, 2, 5, 6;
+  use-inheritance, 3, 11.
+
+_Factors of Organic Evolution_, referred to, 8.
+
+Faculties and organs, 29.
+
+Fertility, 229.
+
+Flat-fish, Mr. Cunningham on, 103.
+
+_Floral Structures_, referred to, 19.
+
+FOCKE, Dr., referred to, 174.
+
+_Fonctions du Cerveau_, referred to, 109.
+
+Food, influence of, 217.
+
+Foot, of man, 23.
+
+Frog, brainless, balancing of, 78.
+
+
+G.
+
+GALTON, Mr. Francis, referred to, 40-48, 100, 103, 134-139, 145, 146,
+152, 154, 156, 300, 303-305; quoted, 46, 100.
+
+Gangrene, effects of, 54, 105.
+
+_Gardener's Chronicle_, quoted, 127.
+
+GAERTNER, Dr., referred to, 206.
+
+GEDDES, Prof., referred to, 15, 20,174.
+
+Gemmules, 47, 145, 155.
+
+Genera and species, 261.
+
+Germ-plasm and Stirp, 40;
+  and pangenesis, 42;
+  isolation of, 137;
+  stability of, 243.
+
+_Germ-plasm_, referred to, 128.
+
+GIARD, Prof., referred to, 14, 174.
+
+Giraffe, co-adaptation in, 64.
+
+GOLTZ, Prof., referred to, 80, 84.
+
+GOULD, Mr., referred to, 210.
+
+Graft-hybridization, 143.
+
+Growth, laws of, 222, 226, 248, 270, 321.
+
+Guinea-pigs, epilepsy of, 104.
+
+GULICK, Mr., referred to, 174, 259, 260, 271; quoted, 224, 273.
+
+_Gute und schlechte Arten_, quoted, 203.
+
+
+H.
+
+Habit, hereditary, 87.
+
+_Habit and Intelligence_, quoted, 225.
+
+Hand, of man, 24.
+
+_Handbook of British Flora_, referred to, 252.
+
+HAYCRAFT, Prof., referred to, 80.
+
+HEAPE, Mr. Walter, referred to, 147.
+
+HENSLOW, Prof. George, referred to, 18-20, 127-132, 174, 208; quoted,
+19, 130, 131.
+
+Heredity, problems of, 39.
+
+HERING, Prof., referred to, 87.
+
+HEWITT, Mr., referred to, 187.
+
+HILL, Prof. Leonard, quoted, 132.
+
+HAECKEL, Prof., referred to, 174, 260, 282.
+
+HOFFMANN, Dr., referred to, 123, 280.
+
+Horse, callosities of, 265.
+
+HUXLEY, Prof. T. H., referred to, 167-170, 185, 256, 275, 283, 307-312;
+quoted, 307-309.
+
+Huxleyan doctrine of species, 167.
+
+_Hyatt_, Prof., referred to, 14, 15.
+
+Hymenoptera, social, 92.
+
+
+I.
+
+_Inadequacy of Natural Selection_, referred to, 65, 95.
+
+_Inconsistencies of Utilitarianism as the Exclusive Theory of Organic
+Evolution_, quoted, 273.
+
+Indifferent characters, 171, 185, 208, 247.
+
+Insects, instincts of, 91.
+
+Instability of useless characters, 186.
+
+Instinct and hereditary habit, 87;
+  of Sphex, 88;
+  of carnivora, 89;
+  of man, 89;
+  Prof. Weismann's views on, 90;
+  of insects, 91.
+
+Intercrossing, 67-71.
+
+Isolation, 223 _et seq._
+
+
+J.
+
+JORDAN, Dr., referred to, 206, 252.
+
+
+K.
+
+Karyokinesis, 140.
+
+KERNER, Prof., referred to, 174, 202-206, 231, 239, 260, 282; quoted,
+203.
+
+KOCH, Dr., referred to, 217.
+
+KOELLIKER, Prof., referred to, 174.
+
+
+L.
+
+Lamarck, referred to, 9-15.
+
+Lamarckism, 9, 61, 113.
+
+LANDOR, A. H. Savage, referred to, 26.
+
+Language and Weismannism, 334.
+
+LANKESTER, Prof. Ray, quoted, 245, 299; referred to, 305.
+
+LESAGE, M., referred to, 126.
+
+_Life and Letters of Charles Darwin_, quoted, 319, 320; referred to, 11.
+
+LUCIANI, referred to, 109.
+
+
+M.
+
+_Making of Flowers_, referred to, 19.
+
+_Manual of British Botany_, referred to, 252.
+
+_Manual of Dental Anatomy_, figure from, 267.
+
+Marsupials, diagnostic characters of, 178.
+
+_Materials for the Study of Variation_, referred to, 36.
+
+MEEHAN, Mr., referred to, 201.
+
+MELDOLA, Prof., referred to, 68.
+
+_Mental Evolution in Animals_, referred to, 25, 88, 89, 92.
+
+_Mental Evolution in Man_, referred to, 31.
+
+MERRIFIELD, Mr., referred to, 211.
+
+Mice, mutilation of tails of, 148.
+
+MIVART, Prof. St. George, referred to, 4, 174, 217.
+
+Monstrosity, in turkeys, 181;
+  in cattle, 196.
+
+MORGAN, Prof. Lloyd, referred to, 33, 36, 174, 271, 300-305; quoted,
+300, 303.
+
+MOSELEY, Prof., referred to, 26.
+
+MURPHY, Mr. J. J., referred to, 224.
+
+Mutilations, inheritance of, 53, 148.
+
+
+N.
+
+NAEGELI, Prof., referred to, 174, 206, 318.
+
+Naked skin of man, 25.
+
+NATHUSIUS, referred to, 188.
+
+Natural Selection, range of, 2, 5, 51, 62, 92;
+  a theory of species, 161, 169;
+  and cave animals, 211;
+  and Porto Santo rabbits, 214.
+
+_Natural Selection and Tropical Nature_, quoted, 23.
+
+_Natural Science_, quoted, 104.
+
+_Nature_, quoted, 132, 223, 245, 299, 325; referred to, 68, 98, 218.
+
+Neo-Darwinian school, 10, 61.
+
+Neo-Lamarckian school, 13, 62, 63.
+
+_Neuer Beitrag zum geologischen Beweis der Darwin'schen Theorie_,
+quoted, 254.
+
+_Neuter Insects and Darwinism_, referred to, 95.
+
+_Neuter Insects and Lamarckism_, referred to, 95.
+
+Neuters of hymenopterous insects, 92.
+
+NEWMAN, Cardinal, referred to, 20.
+
+Niata cattle, 191.
+
+
+O.
+
+OBERSTEINER, Dr., referred to, 105, 106.
+
+_Oesterreichische medicinische Jahrbuecher_, referred to, 105.
+
+_On Truth_, referred to, 217.
+
+Orang-utan, teeth of, 267.
+
+_Organic Evolution_, referred to, 217.
+
+_Origin of the Fittest_, quoted, 16; referred to, 14.
+
+_Origine des Plantes Domestiques, demontree par la culture du Radis
+sauvage_, referred to, 123.
+
+_Origin of Sex_, referred to, 17.
+
+_Origin of Species_, quoted, 3, 4, 181, 182, 186, 188, 190, 261, 262,
+265, 321, 322, 325, 326, 329; referred to, 67, 159, 227, 286.
+
+OSBORN, Prof., referred to, 14, 58, 63.
+
+OWEN, Sir Richard, referred to, 191.
+
+Oxen, skulls of, compared, 192.
+
+Oysters, change of, 217.
+
+
+P.
+
+PACKARD, Prof., referred to, 14, 213.
+
+Pangenesis, 11, 42.
+
+Panmixia, 97, 212, 291.
+
+Parsimony, law of, 51.
+
+Parsnips, variation of, 125.
+
+PASCOE, Mr., referred to, 174; quoted, 254.
+
+PERRIER, Prof., referred to, 14, 93, 95.
+
+PETER, Dr., referred to, 206.
+
+PFEFFER, Herr, referred to, 15.
+
+_Pflueger's Archiv_, referred to, 80.
+
+_Philosophical Transactions_, referred 10, 103.
+
+_Physiological Selection_, referred to, 187, 307, 313, 324; quoted, 188,
+308.
+
+_Pickard-Cambridge_, Rev. O., quoted, 221.
+
+Pig, old Irish, 188.
+
+Plants, influence of climate on, 122-207.
+
+Porto Santo rabbits, 214.
+
+POULTON, E. B., referred to, 36, 217, 337.
+
+_Presidential Address to the Bristol Naturalists Society_, 1891; quoted,
+300, 303.
+
+_Proceedings of the Royal Society_, referred to, 145, 147; quoted, 307.
+
+Protective resemblance, 72.
+
+Protrusion of eyeball, in epileptic guinea-pigs, 111.
+
+
+Q.
+
+QUATREFAGES, M., referred to, 234.
+
+
+R.
+
+Rabbits, and use-inheritance, 96;
+  transplantation of ovaries, 143;
+  Porto Santo, 214.
+
+Radish, variation of, 123.
+
+Rats, scratching, reflex of, 81.
+
+_Raupen und Schmetterlinge der Wetterau_, referred to, 217.
+
+Reflex action and use-inheritance, 64-87.
+
+_Rejoinder to Prof. Weismann_, referred to, 95.
+
+Reversal of selection, 101, 292.
+
+_Revue Generale de Botanie_, referred to, 126.
+
+RICHARDSON, referred to, 188.
+
+ROUX, Prof., referred to, 298.
+
+Rudiments, 294.
+
+RYDER, Prof., referred to, 14.
+
+
+S.
+
+SACHS, Prof., referred to, 15, 174.
+
+"Sally," counting of, 31.
+
+SAUERMANN, Dr., referred to, 218.
+
+SCHAEFER, Prof., referred to, 145.
+
+_Schmetterlinge des Suedwestlichen Deutschlands_, referred to, 217.
+
+SCHMIDT, Dr. Oscar, quoted, 260.
+
+Schools of Evolutionists, 12-20.
+
+SCOTT, Prof., referred to, 63.
+
+Scratching, reflex, in dogs, 80;
+  in rats, 81.
+
+Seasonal changes of butterflies, 210.
+
+SEEBOHM, Mr. Henry, quoted, 173; referred to, 174.
+
+Selection, cessation of, 99, 292;
+  reversal of, 101, 292.
+
+Selection, sexual, 219 _et seq._
+
+Selective value, 73.
+
+Self-adaptation, 18.
+
+SEMPER, Prof. Karl, referred to, 101.
+
+Sexual selection, 219 _et seq._
+
+Sole, pigment of, 104.
+
+Somatogenetic and somatoplasm, 123, 137, 155, 242-249.
+
+_Some Laws of Heredity_, referred to, 24.
+
+Species, stress laid on origin of, 159;
+  necessarily due to natural selection, 168.
+
+---- definitions of, 229.
+
+SPENCER, Herbert, referred to, 8, 64-68, 95.
+
+Sphex, instincts of, 88, 337.
+
+STEBBING, Rev. T. R., quoted, 25.
+
+Sterility, 8.
+
+Stirp and germ-plasm, 40, 47, 138.
+
+_Struggle for Existence between the parts of an Organism_, referred to,
+299.
+
+
+T.
+
+Theory of Heredity, referred to, 40, 47, 137, 154; quoted, 46, 47.
+
+THOMAS, Mr. Oldfield, referred to, 178.
+
+THOMSON, J. A., referred to, 15.
+
+TODD, J. E., referred to, 35.
+
+TOMES, Mr., referred to, 267.
+
+Transfusion of blood in rabbits, 145.
+
+Transplantation of ovaries in rabbits, 143, 147.
+
+Trees, comparison of European and American, 201.
+
+Turkey, tuft of hair of, 181;
+  losing metallic tints, 186.
+
+
+U.
+
+Use-inheritance, 3, 49, 77, 95, 151.
+
+Utility, law of, 8, 20, 159;
+  universality of, 166;
+  of specific characters, 172;
+  of specific characters in birds, 176;
+  of specific characters in Mammals, 178.
+
+
+V.
+
+_Variation of Animals and Plants under Domestication_, quoted, 3, 4, 53,
+66, 96, 187, 189, 191, 193, 195, 213-216, 330, 331.
+
+Varieties, climatic, 228.
+
+Vestigial characters, 171, 184, 261, 294.
+
+VINES, Prof., referred to, 297.
+
+Vitality, plumes of birds due to surplus, 270, 25.
+
+Voice, of man, 25.
+
+
+W.
+
+WAGNER, Moritz, referred to, 217.
+
+WALLACE, Mr. A. R., referred to, 2, 6, 9, 11, 15, 20-35, 50, 66-70, 167,
+169, 172-175, 180-198, 210, 218-227, 235-237, 252, 256, 258, 263-278,
+285, 313-322, 328, 331, 332; quoted, 22-24, 27, 67, 180-182, 185, 186,
+190, 191, 221-223, 235, 236, 269, 273, 313.
+
+Wallacean doctrine of species, 167, 169.
+
+WEISMANN, Prof., referred to, 2, 7, 9, 12, 13, 39-60, 65, 66, 90-105,
+112, 128, 134-142, 148, 149, 151, 152, 155, 156, 173, 241, 243, 244,
+246, 279, 280, 291, 294, 297, 298, 300, 311, 338; quoted, 56, 91, 97,
+152, 243, 244, 297.
+
+Weismannism, diagram of constituent theories, 43, 136;
+  elusiveness of, 334.
+
+_Weismannism once more_, referred to, 66, 95.
+
+WELBY, Hon. Lady, referred to, 90.
+
+WESTPHAL, Prof., referred to, 105, 107.
+
+Withdrawal of foot by reflex action, 75.
+
+WUERTENBERGER, Dr., referred to, 254.
+
+
+Y.
+
+YARRELL, Mr., referred to, 186.
+
+
+
+
+LIST OF OPEN COURT PUBLICATIONS ON SCIENCE
+
+
+The Primary Factors of Organic Evolution. By E. D. Cope. Second
+edition. Pages, 550; illustrations, 121; tables, bibliography, and
+index. Cloth, $2.00 net.
+
+     A comprehensive handbook of the Neo-Lamarckian theory of Evolution.
+
+
+A Mechanico-Physiological Theory of Organic Evolution. By Carl von
+Naegeli. Translated by V. A. Clark and F. A. Waugh. Price, cloth, 60c;
+paper, 30c net.
+
+     A synopsis of his great work on evolution.
+
+
+Darwin and After Darwin. An exposition of the Darwinian Theory and a
+Discussion of Post-Darwinian Questions. By George J. Romanes. 3 vols.
+Price, $4.00 net.
+
+Part I. The Darwinian Theory. Price, cloth, $2.00 net.
+
+Part II. Post-Darwinian Questions: Heredity and Utility. Price, cloth,
+$1.50 net.
+
+Part III. Post-Darwinian Questions. Isolation and Physiological
+Selection. Price, cloth, $1.00 net.
+
+
+An Examination of Weismannism. By George J. Romanes. Price, cloth,
+$1.00 net; paper, 40c net.
+
+     "The best criticism of the subject in our language."--_The
+     Outlook._
+
+
+On Germinal Selection. By August Weismann. Translated by T. J.
+McCormack. Price, paper, 30c net.
+
+
+The Rise of Man. A Sketch of the Origin of the Human Race. By Paul
+Carus. Pages, 97; illustrated. Boards, cloth back, 75c net.
+
+
+The Scope and Content of the Science of Anthropology. By Juul
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+
+     "The science of Anthropology," according to Topinard, "is that
+     branch of natural history which treats of man, and the races of
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+
+
+Experiments on the Generation of Insects. By Francesco Redi.
+Translated from the Italian edition of 1688, by Mab Bigelow.
+Illustrated. Cloth, $2.00 net.
+
+     This book may be counted as one of the classics of the theory of
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+
+
+Ants and Some Other Insects. An Inquiry into the Psychic Powers of
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+Sense. By August Forel. Translated by William M. Wheeler. Price,
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+
+
+Plant Breeding. Comments on the Experiments of Nilsson and Burbank. By
+Hugo de Vries. Pages, xv, 360. Illustrated with 114 half-tone plates
+from nature. Printed on fine paper, in large type. Cloth, gilt top.
+Price, $1.50 net.
+
+     A scientific book in simple language. Intensely interesting as well
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+
+
+Species and Varieties, Their Origin by Mutation. Lectures delivered at
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+the University of Amsterdam. Pages, xviii, 847. Cloth, gilt top, $5.00
+net.
+
+
+The Mutation Theory. Experiments and Observations on the Origin of
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+and A. D. Darbishire. Cloth, per volume, $4.00.
+
+     This is de Vries' great book on a new explanation of the evolution
+     theory, accounting for the formation of species not by the struggle
+     for existence but by mutation.
+
+
+Intracellular Pangenesis. Including a paper on Fertilization and
+Hybridization. By Hugo de Vries. Translated from the German by C.
+Stuart Gager. Cloth, $3.00 net.
+
+     This is de Vries' first important book. It is not very large, but
+     ought to be read by all students of botany, and also by those who
+     are interested in the theory of evolution.
+
+
+On Orthogenesis and the Impotence of Natural Selection in
+Species-Formation. By Th. Eimer. Translated by T. J. McCormack.
+Price, paper, 30c net.
+
+     Another critic of Darwin who claims that organisms develop through
+     transmission of acquired characters.
+
+
+On the Inheritance of Acquired Characters. By Eugenio Rignano.
+Translated by Basil C. H. Harvey. With an Appendix "On the Mnemonic
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+
+     Rignano calls his theory "centro-epigenesis" and is greatly
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+
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+On Double Consciousness. Studies in Experimental Psychology. By
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+net.
+
+     "A most valuable contribution to this important subject which none
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+
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+
+     "He fortifies his theory by such a wealth of exact observation and
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+
+
+The Psychology of Reasoning. By Alfred Binet. Translated from the
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+75c net; paper, 30c net.
+
+     "Like everything that Dr. Binet writes, the subject is stated and
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+
+
+The Diseases of Personality. By Theodule Ribot. Authorized
+translation. Fourth edition. Pages, 157. Cloth, 75c net; paper, 30c.
+
+     Contents: Introduction, Consciousness; Organic Disorders; Affective
+     Disorders; Diseases of the Intellect; Dissolution of Personality.
+
+
+The Diseases of the Will. By Theodule Ribot. Authorized translation.
+Third edition. Pages, vi, 121. Cloth, 75c net; paper, 30c net.
+
+     Contains chapters on impairments of the will and of voluntary
+     attention, the realm of caprices, and extinction of the will.
+
+
+Essay on the Creative Imagination. By Theodule Ribot. Translated
+from the French by A. H. N. Baron, Fellow in Clark University. Cloth,
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+
+     The motor nature of the constructive imagination.
+
+
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+paper, 30c net.
+
+     Contents: Spontaneous or Natural Attention; Voluntary or Artificial
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+
+
+The Diseases of Memory. By Theodule Ribot. Cloth, $1.50 net.
+
+
+Memory. Lectures on the Specific Energies of the Nervous System. By
+Ewald Hering. Fourth edition, containing an additional chapter on the
+Theory of Nerve Activity. Cloth, $1.00 net.
+
+
+The Analysis of Sensations and the Relation of the Physical to the
+Psychical. By Ernst Mach, Emeritus Professor in the University of
+Vienna. Translated by C. M. Williams. Third edition revised and
+supplemented from the fifth German edition by Sydney Waterlow, M.A.
+Pages, xvi, 380. Cuts, 37. Cloth, $1.50 net.
+
+
+Popular Science Lectures. By Ernst Mach, Professor in the University
+of Vienna. Translated from the German by T. J. McCormack. Third
+edition. Pages, 415. Cloth, gilt top, $1.50 net; paper, 60c net.
+
+     A portrayal of the methods and spirit of science, in lectures on
+     mechanics, sound, light, electricity, the conservation of energy,
+     philosophy and education.
+
+
+Man a Machine. By Julien Offray De La Mettrie. Including Frederick
+the Great's Eulogy on La Mettrie and Extracts from La Mettrie's "Natural
+History of the Soul." Translated, with notes, by Gertrude Carman
+Bussey. French-English edition. With a portrait of La Mettrie. Pages,
+226. Cloth, $2.00 net.
+
+     La Mettrie was the most extreme writer among the earliest French
+     materialists. His doctrine is an extension to man of Descartes'
+     doctrine that animals are automata.
+
+
+
+
+PORTRAITS
+
+Philosophical and Psychological Portrait Series
+
+
+Printed on large paper (11 x 14) with tint and platemark. Many of them
+are reproduced from rare paintings, engravings, or original photographs.
+They are suitable for framing and hanging in public and private
+libraries, laboratories, seminaries, recitation and lecture rooms, and
+will be of interest to all concerned in education and general culture.
+
+
+PHILOSOPHICAL
+
+Pythagoras
+Socrates
+Plato
+Aristotle
+Epictetus
+Thomas Aquinas
+St. Augustine
+Averrhoes
+Duns Scotus
+Giordano Bruno
+Bacon
+Hobbes
+Descartes
+Malebranche
+Herbert Spencer
+Schelling
+Spinoza
+Locke
+Berkeley
+Hume
+Montesquieu
+Voltaire
+D'Alembert
+Condillac
+Diderot
+Rousseau
+Leibniz
+Wolff
+Kant
+Fichte
+Hegel
+Schleiermacher
+Schopenhauer
+Herbart
+Feuerbach
+Lotze
+Reid
+Dugald Stewart
+Sir W. Hamilton
+Cousin
+Comte
+Rosmini
+J. Stuart Mill
+
+
+PSYCHOLOGICAL
+
+Cabanis
+Maine de Biran
+Beneke
+E. H. Weber
+Fechner
+Helmholtz
+Wundt
+Hering
+G. T. Ladd
+Aubert
+Mach
+Stumpf
+Exner
+Steinthal
+Bain
+Sully
+Ward
+C. L. Morgan
+Romanes
+Paul Janet
+Ribot
+Taine
+Fouillee
+Binet
+G. Stanley Hall
+
+
+PRICES:
+
+Philosophical and Psychological Portrait Series.
+
+    68 portraits on plate paper, $7.50 per set net. On Japanese vellum,
+        $12.50 per set net.
+
+Philosophical Portrait Series.
+
+    No. 100. 43 portraits on plate paper, $6.25 per set net.
+
+    No. 100a. 43 portraits on Japanese vellum, $8.75 per set net.
+
+    Single portraits on American plate, 25c net.
+
+    Single portraits on Japanese vellum, 35c net.
+
+
+Psychological Portrait Series.
+
+    No. 101. 25 portraits on plate paper, $3.75 net.
+
+    No. 101a. 25 portraits on Japanese vellum, $5.00 net.
+
+    Single portraits on American plate, 25c net.
+
+    Single portraits on Japanese vellum, 35c net.
+
+
+Framing Portrait of Hugo de Vries.
+
+    Platino finish. 10" x 12", unmounted, $1.00 net.
+
+
+Framing Portrait of William James.
+
+    Printed on Japan paper. 11" x 14", $1.00.
+
+
+Portraits of Eminent Mathematicians
+
+Three portfolios edited by David Eugene Smith, Professor of Mathematics
+in Teachers' College, Columbia University, New York.
+
+In response to a widespread demand from those interested in mathematics
+and the history of education, Professor Smith has edited three
+portfolios of the portraits of some of the most eminent of the world's
+contributors to the mathematical sciences. Accompanying each portrait is
+a brief biographical sketch, with occasional notes of interest
+concerning the artist represented. The pictures are of a size that
+allows for framing (11" x 14"), it being the hope that a new interest in
+mathematics may be aroused through the decoration of classrooms by the
+portraits of those who helped to create the science.
+
+Portfolio No. 1.--Twelve great mathematicians down to 1700 A.D.: Thales,
+Pythagorus, Euclid, Archimedes, Leonardo of Pisa, Cardan, Vieta, Napier,
+Descartes, Fermat, Newton, Leibniz.
+
+Portfolio No. 2.--The most eminent founders and promotors of the
+infinitesimal calculus: Cavallieri, Johann and Jakob Bernoulli, Pascal,
+L'Hopital, Barrow, Laplace, Lagrange, Euler, Gauss, Monge, and Niccolo
+Tartaglia.
+
+Portfolio No. 3--Eight portraits selected from the two former
+portfolios, especially adapted for high schools and academies,
+comprising portraits of
+
+    Thales--with whom began the study of scientific geometry;
+
+    Pythagoras--who proved the proposition of the square on the
+        hypotenuse;
+
+    Euclid--whose Elements of Geometry form the basis of all modern
+        text-books;
+
+    Archimedes--whose treatment of the circle, cone, cylinder and sphere
+        influences our work today;
+
+    Descartes--to whom we are indebted for the graphic algebra in our
+        high schools;
+
+    Newton--who generalized the binomial theorem and invented the
+        calculus;
+
+    Napier--who invented logarithms and contributed to trigonometry;
+
+    Pascal--who discovered the "Mystic Hexagram" at the age of sixteen.
+
+
+Portraits of Mathematicians, Part I.
+
+    No. 102. 12 portraits on American plate paper, $3.00 net.
+
+    No. 102a. 12 portraits on Japanese vellum, $5.00 net.
+
+    Single portraits, American plate, 35c net.
+
+    Single portraits, Japanese vellum, 50c net.
+
+
+Portraits of Mathematicians, Part II.
+
+    No. 103. 12 portraits on American plate paper, $3.00 net.
+
+    No. 103a. 12 portraits on Japanese vellum, $5.00 net.
+
+    Single portraits, American plate paper, 35c net.
+
+    Single portraits, Japanese vellum, 50c net.
+
+
+Portraits of Mathematicians, High School Portfolio.
+
+    Eight portraits selected from the two preceding portfolios.
+
+    No. 104. 8 portraits on American plate paper, $2.00 net.
+
+    No. 104a. 8 portraits on Japanese vellum, $3.50 net.
+
+    Single portraits, American plate paper, 35c net.
+
+    Single portraits, Japanese vellum, 50c net.
+
+
+_For Purchasers who may prefer not to frame the Portraits, a neat
+Portfolio can be supplied at an extra cost of $1.00._
+
+
+
+
+       *       *       *       *       *
+
+
+
+
+Transcriber's note:
+
+
+The following typographical errors were correctred.
+
+    |Page |Error         |Correction    |
+    |10   |dicussion     |discussion    |
+    |45   |thoughout     |throughout    |
+    |229  |pyschological |psychological |
+
+The following inconsistent hyphenations were changed.
+
+    |Page |Original       |Changed to    |
+    |34   |inter-crossing |intercrossing |
+    |46   |re-appear      |reappear      |
+    |123  |re-act         |react         |
+    |132  |eye-lid        |eyelid        |
+    |216  |lifetimes      |life-times    |
+    |217  |lifetime       |life-time     |
+    |317  |threefold      |three-fold    |
+
+The following inconsistent hyphenations were not changed.
+
+    "somatoplasm" (3 instances) and "somato-plasm" (2 instances)
+    "twofold" (2) and "two-fold" (1)
+    "interaction" (1) and "inter-action" (1)
+    "supernatural" (1) and "super-natural" (1)
+
+Other changes:
+
+    Page 16 Footnote 10 - double quotes around "acceleration" and
+    "retardation" changed to single quotes. A double quote inserted at
+    the end.
+
+    In the Index - Entries "On Truth" and "Orang-utan, teeth of" moved
+    from under "M" to under "O".
+
+
+
+***END OF THE PROJECT GUTENBERG EBOOK DARWIN, AND AFTER DARWIN, VOLUME II
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