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+The Project Gutenberg EBook of Finger Prints, by Francis Galton
+
+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: Finger Prints
+
+Author: Francis Galton
+
+Release Date: August 5, 2011 [EBook #36979]
+
+Language: English
+
+Character set encoding: ASCII
+
+*** START OF THIS PROJECT GUTENBERG EBOOK FINGER PRINTS ***
+
+
+
+
+Produced by The Online Distributed Proofreading Team at
+https://www.pgdp.net (This file was produced from images
+generously made available by The Internet Archive.)
+
+
+
+
+
+
+
+
+
+FINGER PRINTS
+
+
+
+
+ FINGER PRINTS
+
+
+ [Illustration: FINGER PRINTS OF THE AUTHOR]
+
+
+ BY
+ FRANCIS GALTON, F.R.S., ETC.
+
+
+ London
+ MACMILLAN AND CO.
+ AND NEW YORK
+ 1892
+
+ _All rights reserved_
+
+
+
+
+CONTENTS
+
+
+ CHAPTER I
+
+ PAGE
+
+ INTRODUCTION 1
+
+ Distinction between creases and ridges 1
+
+ Origin of the inquiry 2
+
+ Summaries of the subsequent chapters 3-21
+
+ Viz. of ii., 3; iii., 4; iv., 5;
+ v., 5; vi., 8; vii., 10;
+ viii., 12; ix., 13; x., 14;
+ xi., 16; xii., 17; xiii., 19;
+
+
+ CHAPTER II
+
+ PREVIOUS USE OF FINGER PRINTS 22
+
+ Superstition of personal contact 22
+
+ Rude hand-prints 23
+
+ Seals to documents 23
+
+ Chinese finger marks 24
+
+ The _tipsahi_ of Bengal 24
+
+ Nail-marks on Assyrian bricks 25
+
+ Nail-mark on Chinese coins 25
+
+ Ridges and cheiromancy--China, Japan, and by negroes 26
+
+ Modern usage--Bewick, Fauld, Tabor, and G. Thompson 26
+
+ Their official use by Sir W. J. Herschel 27
+
+
+ CHAPTER III
+
+ METHODS OF PRINTING 30
+
+ Impression on polished glass or razor 30
+
+ The two contrasted methods of printing 31
+
+ General remarks on printing from reliefs--ink; low relief
+ of ridges; layer of ink; drying due to oxidisation 32-34
+
+ Apparatus at my own laboratory--slab; roller; benzole
+ (or equivalent); funnel; ink; cards 35-38
+
+ Method of its manipulation 38-40
+
+ Pocket apparatus 40
+
+ Rollers and their manufacture 40
+
+ Other parts of the apparatus 41
+
+ Folders--long serviceable if air be excluded 42
+
+ Lithography 43
+
+ Water colours and dyes 44
+
+ Sir W. Herschel's official instructions 45
+
+ Printing as from engraved plates--Prof. Ray Lankester;
+ Dr. L. Robinson 45
+
+ Methods of Dr. Forgeot 46
+
+ Smoke prints--mica; adhesive paper, by licking with tongue 47-48
+
+ Plumbago; whitening 49
+
+ Casts--sealing-wax; dentist's wax; gutta-percha; undried
+ varnish; collodion 49-51
+
+ Photographs 51
+
+ Prints on glass and mica for lantern 51
+
+ Enlargements--photographic, by camera lucida, pantagraph 52-53
+
+
+ CHAPTER IV
+
+ THE RIDGES AND THEIR USES 54
+
+ General character of the ridges 54
+
+ Systems on the palm--principal ones; small interpolated
+ systems 54-55
+
+ Cheiromantic creases--their directions; do not strictly
+ correspond with those of ridges 56-57
+
+ Ridges on the soles of the feet 57
+
+ Pores 57
+
+ Development:--embryology; subsequent growth; disintegration
+ by age, by injuries 58-59
+
+ Evolution 60
+
+ Apparent use as regards pressure--theoretic; experiment
+ with compass points 60-61
+
+ Apparent use as regards rubbing--thrill thereby occasioned 62-63
+
+
+ CHAPTER V
+
+ PATTERNS: THEIR OUTLINES AND CORES 64
+
+ My earlier failures in classifying prints; their causes 64-66
+
+ The triangular plots 67
+
+ Outlines of patterns--eight sets of ten digits given as
+ examples 69-70
+
+ Supplies of ridges to pattern 71
+
+ Letters that read alike when reversed 71
+
+ Magnifying glasses, spectacles, etc. 72
+
+ Rolled impressions, their importance 73
+
+ Standard patterns, cores, and their nomenclature 74-77
+
+ Direction of twist, nomenclature 78
+
+ Arches, loops, whorls 78
+
+ Transitional cases 79
+
+ The nine genera 80
+
+ Measurements--by ridge-intervals; by aid of bearings like
+ compass 82-84
+
+ Purkenje--his _Commentatio_ and a translation of it in part 84-88
+
+
+ CHAPTER VI
+
+ PERSISTENCE 89
+
+ Evidence available 89
+
+ About thirty-five points of reference in each print 90
+
+ Photo-enlargement; orientation; tracing axes of ridges 90-91
+
+ Ambiguities in minutiae 91
+
+ V. H. Hd. as child and boy, a solitary change in one of
+ the minutiae 92
+
+ Eight couplets from other persons 93
+
+ One from Sir W. G. 95
+
+ Summary of 389 comparisons 96
+
+ Ball of a thumb 96
+
+ Results as to persistence 97
+
+
+ CHAPTER VII
+
+ EVIDENTIAL VALUE 100
+
+ Method of rough comparison 100
+
+ Chance against guessing a pattern 101
+
+ Number of independent elements in a print--squares
+ respectively of one, six, and five ridge-intervals in
+ side 101-103
+
+ Interpolation, three methods of 103-105
+
+ Local accidents inside square 107
+
+ Uncertainties outside it 109
+
+ Compound results 110
+
+ Effect of failure in one, two, or more prints 111
+
+ Final conclusions--Jezebel 112-113
+
+
+ CHAPTER VIII
+
+ PECULIARITIES OF THE DIGITS 114
+
+ Frequency per cent of arches, loops, and whorls
+ generally, and on the several digits 114-115
+
+ Characteristic groups of digits 116-118
+
+ Relationships between the digits 119
+
+ Centesimal scale of relationship 124-126
+
+ Digits of same and of different names 130
+
+
+ CHAPTER IX
+
+ METHODS OF INDEXING 131
+
+ Use of an index 131
+
+ Method of few conspicuous differences in many fingers 131
+
+ Specimen index 133
+
+ Order in which the digits are noted 134
+
+ Examples of indexing 135
+
+ Effect of regarding slopes 135
+
+ Number of index-heads required for 100 sets in each of
+ twelve different methods 136-138
+
+ _i_ and _o_ in forefingers only 138
+
+ List of commonest index-headings 140
+
+ Number of headings to 100 sets, according to the digits
+ that are noted 142
+
+ Transitional cases; sub-classifications 143-144
+
+ Symbols for patterns 144
+
+ Storing cards 145
+
+ Number of entries under each head when only the first
+ three fingers are noted 146
+
+
+ CHAPTER X
+
+ PERSONAL IDENTIFICATION 147
+
+ Printers and photographers 147
+
+ Use of means of identification to honest persons; in
+ regard to criminals 148-149
+
+ Major Ferris, Mr. Tabor, N. Borneo 149-153
+
+ Best digits for registration purposes 153
+
+ Registration of criminals--M. Bertillon 154
+
+ Details of _Bertillonage_; success attributed to it; a
+ theoretic error 155-158
+
+ Verification on a small scale 158-162
+
+ Experiences in the United States 163
+
+ Body marks; teeth 165-166
+
+ Value of finger prints for search in a register 166
+
+ Identification by comparison 167
+
+ Remarks by M. Herbette 168
+
+
+ CHAPTER XI
+
+ HEREDITY 170
+
+ Different opinions 170
+
+ Larger meaning of heredity 170
+
+ Connection between filial and fraternal relationships 171
+
+ Fraternity, a faulty word but the best available 171
+
+ A and B brothers 172
+
+ Test case of calculated randoms 173
+
+ Fraternities by double A. L. W. events 175
+
+ The C. standard patterns 177
+
+ Limitation of couplets in large fraternities 178
+
+ Test of accurate classification 179
+
+ Fraternities by double C. events 181
+
+ Centesimal scale applied 184
+
+ Twins 185
+
+ Children of like-patterned parents 187
+
+ Simple filial relationship 190
+
+ Influences of father and mother 190
+
+
+ CHAPTER XII
+
+ RACES AND CLASSES 192
+
+ Data for races 192
+
+ Racial differences are statistical only 193
+
+ Calculations by Mr. F. H. Collins 193
+
+ Hebrew peculiarities 194
+
+ Negro peculiarities, questionable 196
+
+ Data for different classes in temperament, faculty, etc.,
+ and results 197
+
+ M. Fere 197
+
+
+ CHAPTER XIII
+
+ GENERA 198
+
+ Type, meaning of 198
+
+ Law of frequency of error 198
+
+ Discussion of three elements in the loops on either thumb 200-207
+
+ Proportions of typical loops 209
+
+ The patterns are transmitted under conditions of panmixia,
+ yet do not blend 209
+
+ Their genera are not due to selection; inference 210
+
+ Sports; variations 211
+
+
+
+
+DESCRIPTION OF THE TABLES
+
+
+ PAGE
+
+ Summary of evidence in favour of finger marks being persistent 96
+
+ Interpolation of ridges 104
+
+ I. Percentage frequency of Arches, Loops, and Whorls on the
+ different digits, as observed in the 5000 digits of 500
+ different persons 115
+
+ II. Distribution of the A. L. W. patterns on the corresponding
+ digits of the two hands 116
+
+ III. Percentage frequency of Arches on the digits of the two
+ hands 117
+
+ IV. Percentage frequency of Loops on the digits of the two hands 118
+
+ V. Percentage frequency of Whorls on the digits of the two hands 118
+
+ VI_a_. Percentage of cases in which the same class of pattern
+ occurs in the same digits of the two hands 120
+
+ VI_b_. Percentage of cases in which the same class of pattern
+ occurs in various couplets of different digits 120
+
+ VII. Couplets of fingers of different names in the same and in
+ the opposite hands 121
+
+ VIII. Measures of relationship between the digits on a
+ centesimal scale 129
+
+ IX. Index to 100 sets of finger prints 133
+
+ X. Number of different index-heads in 100 sets, according to
+ the number of digits noted 136
+
+ XI. Number of entries under the same heads in 100 sets 139
+
+ XII. Index-headings under which more than 1 per cent of the
+ sets were registered in 500 sets 140
+
+ XIII. Percentage of entries falling under a single head in 100,
+ 300, and 500 sets 141
+
+ XIV. Number of different index-headings in 100 sets, according
+ to the number of fingers in each set, and to the method of
+ indexing 142
+
+ XV. Number of entries in 500 sets, each of the fore, middle,
+ and ring-fingers only 146
+
+ XVI. Number of cases of various anthropometric data that
+ severally fell in the three classes of large, medium, and
+ small, when certain limiting values were adopted 159
+
+ XVII. Distribution of 500 sets of measures, each set consisting
+ of five elements, into classes 160
+
+ XVIII. Number of the above sets that fell under the same
+ headings 161
+
+ XIX. Further analysis of the two headings that contained the
+ most numerous entries 162
+
+ XX. Observed random couplets 174
+
+ XXI. Calculated random couplets 174
+
+ XXII. Observed fraternal couplets 175
+
+ XXIII. Fraternal couplets--random, observed, and utmost
+ feasible 176
+
+ XXIV. Three fingers of right hand in 150 fraternal couplets 181
+
+ XXV. Three fingers of right hand in 150 fraternal couplets--
+ random and observed 182
+
+ XXVI. Three fingers of right hand in 150 fraternal couplets--
+ resemblance measured on centesimal scale 182
+
+ XXVII. Twins 186
+
+ XXVIII. Children of like-patterned parents 188
+
+ XXIX. Paternal and maternal influence 190
+
+ XXX. Different races, percentage frequency of arches in
+ fore-finger 194
+
+ XXXI. Distribution of number of ridges in AH, and of other
+ measures in loops 203
+
+ XXXII. Ordinates to their schemes of distribution 204
+
+ XXXIII. Comparison of the above with calculated values 205
+
+ XXXIV. Proportions of a typical loop on the right and left
+ thumbs respectively 209
+
+
+
+
+DESCRIPTION OF THE PLATES
+
+
+ PAGE
+
+ I.--Fig. 1. Chinese coin with the symbol of the nail-mark of
+ the Empress Wen-teh 25
+
+ Fig. 2. Order on a camp sutler by Mr. Gilbert Thompson, who
+ used his finger print for the same purpose as the scroll-work
+ in cheques, viz. to ensure the detection of erasures 27
+
+ II.--Fig. 3. Form of card used at my anthropometric laboratory
+ for finger prints. It shows the places where they are severally
+ impressed, whether dabbed or rolled (p. 40), and the hole by
+ which they are secured in their box 145
+
+ Fig. 4. Small printing roller, used in the pocket apparatus,
+ actual size. It may be covered either with india-rubber tubing
+ or with roller composition 40
+
+ III.--Fig. 5. Diagram of the chief peculiarities of ridges,
+ called here _minutiae_ (the scale is about eight times the
+ natural size) 54
+
+ Fig. 6. The systems of ridges and the creases in the palm,
+ indicated respectively by continuous and by dotted lines. Nos.
+ 2, 3, 4, and 5 show variations in the boundaries of the systems
+ of ridges, and places where smaller systems are sometimes
+ interpolated 54
+
+ IV.--Fig. 7. The effects of scars and cuts on the ridges: _a_
+ is the result of a deep ulcer; _b_ the finger of a tailor
+ (temporarily) scarred by the needle; _c_ the result of a deep
+ cut 59
+
+ Fig. 8. Formation of the interspace: filled in (3) by a loop;
+ in (4) by a scroll. The triangular plot or plots are indicated.
+ In (1) there is no interspace, but a succession of arches are
+ formed, gradually flattening into straight lines 67
+
+ V.--Fig. 9. Specimens of rolled thumb prints, of the natural
+ size, in which the patterns have been outlined, p. 69, and on
+ which lines have been drawn for orientation and charting 68
+
+ VI.--Fig. 10. Specimens of the outlines of the patterns on the
+ ten digits of eight different persons, not selected but taken
+ as they came. Its object is to give a general idea of the degree
+ of their variety. The supply of ridges from the _inner_ (or
+ thumb side) are coloured blue, those from the _outer_ are red
+ (the scale is of the natural size) 70
+
+ VII.--Fig. 11. Standard patterns of Arches, together with some
+ transitional forms, all with their names below 75
+
+ Fig. 12. As above, with respect to Loops 75
+
+ VIII.--Fig. 13. As above, with respect to Whorls 75
+
+ Fig. 14. Cores to Loops, which may consist either of single
+ lines, here called _rods_, or of a recurved line or _staple_,
+ while the ridges that immediately envelops them is called an
+ _envelope_ 76
+
+ Fig. 15. Cores to Whorls 77
+
+ IX.--Fig. 15. Transitional patterns, enlarged three times,
+ between Arches and either Loops or Whorls 79
+
+ X.--Fig. 16. Transitional patterns, as above, but between Loops
+ and Whorls 79
+
+ XI.--Fig. 17. Diagram showing the nine genera formed by the
+ corresponding combinations of the two letters by which they are
+ expressed, each being _i_, _j_, or _o_ as the case may be. The
+ first two diagrams are Arches, and not strictly patterns at all,
+ but may with some justice be symbolised by _jj_ 80
+
+ Fig. 18. Ambiguities in minutiae, showing that certain details in
+ them are not to be trusted, while others are 92
+
+ XII.--Fig. 19. The illustrations to Purkenje's _Commentatio_.
+ They are photo-lithographed from the original, which is not
+ clearly printed 86
+
+ XIII.--Fig. 20. Enlarged impressions of the same two fingers
+ of V. H. Hd., first when a child of 2-1/2, and subsequently when
+ a boy of 15 years of age. The lower pair are interesting from
+ containing the unique case of failure of exact coincidence yet
+ observed. It is marked A. The numerals indicate the
+ correspondences 92
+
+ XIV.--Fig. 21. Contains portions on an enlarged scale of eight
+ couplets of finger prints, the first print in each couplet
+ having been taken many years before the second, as shown by the
+ attached dates. The points of correspondence in each couplet are
+ indicated by similar numerals 93
+
+ XV.--Fig. 22. The fore-finger of Sir W. J. Herschel as printed
+ on two occasions, many years apart (enlarged scale). The numerals
+ are here inserted on a plan that has the merit of clearness, but
+ some of the lineations are thereby sacrificed 95
+
+ Fig. 23. Shows the periods of life over which the evidence of
+ identity extends in Figs 20-22. [By an oversight, not perceived
+ until too late for remedy, the bottom line begins at aet. 62
+ instead of 67] 97
+
+
+
+
+CHAPTER I
+
+INTRODUCTION
+
+
+The palms of the hands and the soles of the feet are covered with two
+totally distinct classes of marks. The most conspicuous are the creases or
+folds of the skin which interest the followers of palmistry, but which are
+no more significant to others than the creases in old clothes; they show
+the lines of most frequent flexure, and nothing more. The least
+conspicuous marks, but the most numerous by far, are the so-called
+papillary ridges; they form the subject of the present book. If they had
+been only twice as large as they are, they would have attracted general
+attention and been commented on from the earliest times. Had Dean Swift
+known and thought of them, when writing about the Brobdingnags, whom he
+constructs on a scale twelve times as great as our own, he would certainly
+have made Gulliver express horror at the ribbed fingers of the giants who
+handled him. The ridges on their palms would have been as broad as the
+thongs of our coach-whips.
+
+Let no one despise the ridges on account of their smallness, for they are
+in some respects the most important of all anthropological data. We shall
+see that they form patterns, considerable in size and of a curious variety
+of shape, whose boundaries can be firmly outlined, and which are little
+worlds in themselves. They have the unique merit of retaining all their
+peculiarities unchanged throughout life, and afford in consequence an
+incomparably surer criterion of identity than any other bodily feature.
+They may be made to throw welcome light on some of the most interesting
+biological questions of the day, such as heredity, symmetry, correlation,
+and the nature of genera and species. A representation of their lineations
+is easily secured in a self-recorded form, by inking the fingers in the
+way that will be explained, and pressing them on paper. There is no
+prejudice to be overcome in procuring these most trustworthy sign-manuals,
+no vanity to be pacified, no untruths to be guarded against.
+
+My attention was first drawn to the ridges in 1888 when preparing a
+lecture on Personal Identification for the Royal Institution, which had
+for its principal object an account of the anthropometric method of
+Bertillon, then newly introduced into the prison administration of France.
+Wishing to treat the subject generally, and having a vague knowledge of
+the value sometimes assigned to finger marks, I made inquiries, and was
+surprised to find, both how much had been done, and how much there
+remained to do, before establishing their theoretical value and practical
+utility.
+
+Enough was then seen to show that the subject was of real importance, and
+I resolved to investigate it; all the more so, as the modern processes of
+photographic printing would enable the evidence of such results as might
+be arrived at, to be presented to the reader on an enlarged and easily
+legible form, and in a trustworthy shape. Those that are put forward in
+the following pages, admit of considerable extension and improvement, and
+it is only the fact that an account of them seems useful, which causes me
+to delay no further before submitting what has thus far been attained, to
+the criticism of others.
+
+I have already published the following memoirs upon this subject:
+
+ 1. "Personal Identification." _Journal Royal Inst._ 25th May 1888, and
+ _Nature_, 28th June 1888.
+
+ 2. "Patterns in Thumb and Finger Marks." _Phil. Trans. Royal Society_,
+ vol. clxxxii. (1891) b. pp. 1-23. [This almost wholly referred to
+ thumb marks.]
+
+ 3. "Method of Indexing Finger Marks." _Proc. Royal Society_, vol.
+ xlix. (1891).
+
+ 4. "Identification by Finger Tips." _Nineteenth Century_, August 1891.
+
+This first and introductory chapter contains a brief and orderly summary
+of the contents of those that follow.
+
+The second chapter treats of the previous employment of finger prints
+among various nations, which has been almost wholly confined to making
+daubs, without paying any regard to the delicate lineations with which
+this book is alone concerned. Their object was partly superstitious and
+partly ceremonial; superstitious, so far as a personal contact between
+the finger and the document was supposed to be of mysterious efficacy:
+ceremonial, as a formal act whose due performance in the presence of
+others could be attested. A few scattered instances are mentioned of
+persons who had made finger prints with enough care to show their
+lineations, and who had studied them; some few of these had used them as
+signatures. Attention is especially drawn to Sir William Herschel, who
+brought the method of finger prints into regular official employment when
+he was "Collector" or chief administrator of the Hooghly district in
+Bengal, and my large indebtedness to him is expressed in this chapter and
+in other places.
+
+In the third chapter various methods of making good prints from the
+fingers are described at length, and more especially that which I have now
+adopted on a somewhat large scale, at my anthropometric laboratory, which,
+through the kindness of the authorities of South Kensington, is at present
+lodged in the galleries of their Science Collections. There, the ten
+digits of both hands of all the persons who come to be measured, are
+impressed with clearness and rapidity, and a very large collection of
+prints is steadily accumulating, each set being, as we shall see, a
+sign-manual that differentiates the person who made it, throughout the
+whole of his life, from all the rest of mankind.
+
+Descriptions are also given of various methods of enlarging a finger print
+to a convenient size, when it is desired to examine it closely.
+Photography is the readiest of all; on the other hand the prism (as in a
+camera lucida) has merits of its own, and so has an enlarging pantagraph,
+when it is furnished with a small microscope and cross wires to serve as a
+pointer.
+
+In the fourth chapter the character and purpose of the ridges, whose
+lineations appear in the finger print, are discussed. They have been the
+topic of a considerable amount of careful physiological study in late
+years, by writers who have investigated their development in early periods
+of unborn life, as well as their evolutionary history. They are perfectly
+defined in the monkeys, but appear in a much less advanced stage in other
+mammalia. Their courses run somewhat independently of the lines of
+flexure. They are studded with pores, which are the open mouths of ducts
+proceeding from the somewhat deeply-seated glands which secrete
+perspiration, so one of their functions is to facilitate the riddance of
+that excretion. The ridges increase in height as the skin is thickened by
+hard usage, until callosities begin to be formed, which may altogether
+hide them. But the way in which they assist the touch and may tend to
+neutralise the dulling effect of a thick protective skin, is still
+somewhat obscure. They certainly seem to help in the discrimination of the
+character of surfaces that are variously rubbed between the fingers.
+
+These preliminary topics having been disposed of, we are free in the fifth
+chapter to enter upon the direct course of our inquiry, beginning with a
+discussion of the various patterns formed by the lineations. It will be
+shown how systems of parallel ridges sweep in bold curves across the
+palmar surface of the hand, and how, whenever the boundaries of two
+systems diverge, the interspace is filled up by a compact little system of
+its own, variously curved or whorled, having a fictitious resemblance to
+an eddy between two currents. An interspace of this kind is found in the
+bulb of each finger. The ridges run in parallel lines across the finger,
+up to its last joint, beyond which the insertion of the finger-nail causes
+a compression of the ridges on either side; their intermediate courses are
+in consequence so much broadened out that they commonly separate, and form
+two systems with an interspace between them. The independent patterns that
+appear in this interspace upon the bulbs of the fingers, are those with
+which this book is chiefly concerned.
+
+At first sight, the maze formed by the minute lineations is bewildering,
+but it is shown that every interspace can be surely outlined, and when
+this is done, the character of the pattern it encloses, starts
+conspicuously into view. Examples are given to show how the outlining is
+performed, and others in which the outlines alone are taken into
+consideration. The cores of the patterns are also characteristic, and are
+described separately. It is they alone that have attracted the notice of
+previous inquirers. The outlines fall for the most part into nine distinct
+genera, defined by the relative directions of the divergent ridges that
+enclose them. The upper pair (those that run towards the finger-tip) may
+unite, or one or other of them may surmount the other, thus making three
+possibilities. There are three similar possibilities in respect to the
+lower pair; so, as any one of the first group may be combined with any one
+of the second, there are 3 x 3, or nine possibilities in all. The practice
+of somewhat rolling the finger when printing from it, is necessary in
+order to impress enough of its surface to ensure that the points at which
+the boundaries of the pattern begin to diverge, shall be always included.
+
+Plates are given of the principal varieties of patterns, having regard
+only to their more fundamental differences, and names are attached for the
+convenience of description; specimens are also given of the outlines of
+the patterns in all the ten digits of eight different persons, taken at
+hazard, to afford a first idea of the character of the material to be
+dealt with. Another and less minute system of classification under three
+heads is then described, which is very useful for rough preliminary
+purposes, and of which frequent use is made further on. It is into Arches,
+Loops, and Whorls. In the Arches, there is no pattern strictly speaking,
+for there is no interspace; the need for it being avoided by a successive
+and regular broadening out of the ridges as they cross the bulb of the
+finger. In Loops, the interspace is filled with a system of ridges that
+bends back upon itself, and in which no one ridge turns through a complete
+circle. Whorls contain all cases in which at least one ridge turns through
+a complete circle, and they include certain double patterns which have a
+whorled appearance. The transitional cases are few; they are fully
+described, pictured, and classified. One great advantage of the rude A.
+L. W. system is that it can be applied, with little risk of error, to
+impressions that are smudged or imperfect; it is therefore very useful so
+far as it goes. Thus it can be easily applied to my own finger prints on
+the title-page, made as they are from digits that are creased and
+roughened by seventy years of life, and whose impressions have been
+closely clipped in order to fit them into a limited space.
+
+A third method of classification is determined by the origin of the ridges
+which supply the interspace, whether it be from the thumb side or the
+little-finger side; in other words, from the Inner or the Outer side.
+
+Lastly, a translation from the Latin is given of the famous Thesis or
+_Commentatio_ of Purkenje, delivered at the University of Breslau in 1823,
+together with his illustrations. It is a very rare pamphlet, and has the
+great merit of having first drawn attention to the patterns and attempted
+to classify them.
+
+In the sixth chapter we reach the question of Persistence: whether or no
+the patterns are so durable as to afford a sure basis for identification.
+The answer was different from what had been expected. So far as the
+proportions of the patterns go, they are _not_ absolutely fixed, even in
+the adult, inasmuch as they change with the shape of the finger. If the
+finger is plumped out or emaciated, or variously deformed by usage, gout,
+or age, the proportions of the pattern will vary also. Two prints of the
+same finger, one taken before and the other after an interval of many
+years, cannot be expected to be as closely alike as two prints similarly
+made from the same woodcut. They are far from satisfying the shrewd test
+of the stereoscope, which shows if there has been an alteration even of a
+letter in two otherwise duplicate pages of print. The measurements vary at
+different periods, even in the adult, just as much if not more than his
+height, span, and the lengths of his several limbs. On the other hand, the
+numerous bifurcations, origins, islands, and enclosures in the ridges that
+compose the pattern, are proved to be _almost beyond change_. A comparison
+is made between the pattern on a finger, and one on a piece of lace; the
+latter may be stretched or shrunk as a whole, but the threads of which it
+is made retain their respective peculiarities. The evidence on which these
+conclusions are founded is considerable, and almost wholly derived from
+the collections made by Sir W. Herschel, who most kindly placed them at my
+disposal. They refer to one or more fingers, and in a few instances to the
+whole hand, of fifteen different persons. The intervals before and after
+which the prints were taken, amount in some cases to thirty years. Some of
+them reach from babyhood to boyhood, some from childhood to youth, some
+from youth to advanced middle age, one from middle life to incipient old
+age. These four stages nearly include the whole of the ordinary life of
+man. I have compared altogether some 700 points of reference in these
+couplets of impressions, and only found a single instance of discordance,
+in which a ridge that was cleft in a child became united in later years.
+Photographic enlargements are given in illustration, which include between
+them a total of 157 pairs of points of reference, all bearing distinctive
+numerals to facilitate comparison and to prove their unchangeableness.
+Reference is made to another illustrated publication of mine, which raises
+the total number of points compared to 389, all of which were successful,
+with the single exception above mentioned. The fact of an almost complete
+persistence in the peculiarities of the ridges from birth to death, may
+now be considered as determined. They existed before birth, and they
+persist after death, until effaced by decomposition.
+
+In the seventh chapter an attempt is made to appraise the evidential value
+of finger prints by the common laws of Probability, paying great heed not
+to treat variations that are really correlated, as if they were
+independent. An artifice is used by which the number of portions is
+determined, into which a print may be divided, in each of which the purely
+local conditions introduce so much uncertainty, that a guess derived from
+a knowledge of the outside conditions is as likely as not to be wrong. A
+square of six ridge-intervals in the side was shown by three different
+sets of experiments to be larger than required; one of four
+ridge-intervals in the side was too small, but one of five ridge-intervals
+appeared to be closely correct. A six-ridge interval square was, however,
+at first adopted, in order to gain assurance that the error should be on
+the safe side. As an ordinary finger print contains about twenty-four of
+these squares, the uncertainty in respect to the entire contents of the
+pattern _due to this cause alone_, is expressed by a fraction of which the
+numerator is 1, and the denominator is 2 multiplied into itself
+twenty-four times, which amounts to a number so large that it requires
+eight figures to express it.
+
+A further attempt was made to roughly appraise the neglected uncertainties
+relating to the outside conditions, but large as they are, they seem much
+inferior in their joint effect to the magnitude of that just discussed.
+
+Next it was found possible, by the use of another artifice, to obtain some
+idea of the evidential value of identity when two prints agree in all but
+one, two, three, or any other number of particulars. This was done by
+using the five ridge-interval squares, of which thirty-five may be
+considered to go into a single finger print, being about the same as the
+number of the bifurcations, origins, and other points of comparison. The
+accidental similarity in their numbers enables us to treat them roughly as
+equivalent. On this basis the well-known method of binomial calculation is
+easily applied, with the general result that, notwithstanding a failure of
+evidence in a few points, as to the identity of two sets of prints, each,
+say, of three fingers, amply enough evidence would be supplied by the
+remainder to prevent any doubt that the two sets of prints were made by
+the same person. When a close correspondence exists in respect to all the
+ten digits, the thoroughness of the differentiation of each man from all
+the rest of the human species is multiplied to an extent far beyond the
+capacity of human imagination. There can be no doubt that the evidential
+value of identity afforded by prints of two or three of the fingers, is so
+great as to render it superfluous to seek confirmation from other sources.
+
+The eighth chapter deals with the frequency with which the several kinds
+of patterns appear on the different digits of the same person, severally
+and in connection. The subject is a curious one, and the inquiry
+establishes unexpected relationships and distinctions between different
+fingers and between the two hands, to whose origin there is at present no
+clue. The relationships are themselves connected in the following
+way;--calling any two digits on one of the hands by the letters A and B
+respectively, and the digit on the other hand, that corresponds to B, by
+the symbol B1, then the kinship between A and B1 is identical, in a
+statistical sense, with the kinship between A and B.
+
+The chief novelty in this chapter is an attempt to classify nearness of
+relationship upon a centesimal scale, in which the number of
+correspondences due to mere chance counts as 0 deg., and complete identity as
+100 deg. It seems reasonable to adopt the scale with only slight reservation,
+when the average numbers of the Arches, Loops, and Whorls are respectively
+the same in the two kinds of digit which are compared together; but when
+they differ greatly, there are no means free from objection, of
+determining the 100 deg. division of the scale; so the results, if noted at
+all, are subject to grave doubt.
+
+Applying this scale, it appears that digits on opposite hands, which bear
+the same name, are more nearly related together than digits bearing
+different names, in about the proportion of three to two. It seems also,
+that of all the digits, none are so nearly related as the middle finger to
+the two adjacent ones.
+
+In the ninth chapter, various methods of indexing are discussed and
+proposed, by which a set of finger prints may be so described by a few
+letters, that it can be easily searched for and found in any large
+collection, just as the name of a person is found in a directory. The
+procedure adopted, is to apply the Arch-Loop-Whorl classification to all
+ten digits, describing each digit in the order in which it is taken, by
+the letter _a_, _l_, or _w_, as the case may be, and arranging the results
+in alphabetical sequence. The downward direction of the slopes of loops on
+the fore-fingers is also taken into account, whether it be towards the
+Inner or the Outer side, thus replacing L on the fore-finger by either _i_
+or _o_.
+
+Many alternative methods are examined, including both the recognition and
+the non-recognition of all sloped patterns. Also the gain in
+differentiation, when all the ten digits are catalogued, instead of only a
+few of them. There is so much correlation between the different fingers,
+and so much peculiarity in each, that theoretical notions of the value of
+different methods of classification are of little worth; it is only by
+actual trial that the best can be determined. Whatever plan of index be
+adopted, many patterns must fall under some few headings and few or no
+patterns under others, the former class resembling in that respect the
+Smiths, Browns, and other common names that occur in directories. The
+general value of the index much depends on the facility with which these
+frequent forms can be broken up by sub-classification, the rarer forms
+being easily dealt with. This branch of the subject has, however, been but
+lightly touched, under the belief that experience with larger collections
+than my own, was necessary before it could be treated thoroughly; means
+are, however, indicated for breaking up the large battalions, which have
+answered well thus far, and seem to admit of considerable extension. Thus,
+the number of ridges in a loop (which is by far the commonest pattern) on
+any particular finger, at the part of the impression where the ridges are
+cut by the axis of the loop, is a fairly definite and effective datum as
+well as a simple one; so also is the character of its inmost lineation, or
+core.
+
+In the tenth chapter we come to a practical result of the inquiry, namely,
+its possible use as a means of differentiating a man from his fellows. In
+civil as well as in criminal cases, the need of some such system is shown
+to be greatly felt in many of our dependencies; where the features of
+natives are distinguished with difficulty; where there is but little
+variety of surnames; where there are strong motives for prevarication,
+especially connected with land-tenure and pensions, and a proverbial
+prevalence of unveracity.
+
+It is also shown that the value to honest men of sure means of
+identifying themselves is not so small among civilised nations even in
+peace time, as to be disregarded, certainly not in times of war and of
+strict passports. But the value to honest men is always great of being
+able to identify offenders, whether they be merely deserters or formerly
+convicted criminals, and the method of finger prints is shown to be
+applicable to that purpose. For aid in searching the registers of a
+criminal intelligence bureau, its proper rank is probably a secondary one;
+the primary being some form of the already established Bertillon
+anthropometric method. Whatever power the latter gives of successfully
+searching registers, that power would be multiplied many hundredfold by
+the inclusion of finger prints, because their peculiarities are entirely
+unconnected with other personal characteristics, as we shall see further
+on. A brief account is given in this chapter of the Bertillon system, and
+an attempt is made on a small scale to verify its performance, by
+analysing five hundred sets of measures made at my own laboratory. These,
+combined with the quoted experiences in attempting to identify deserters
+in the United States, allow a high value to this method, though not so
+high as has been claimed for it, and show the importance of supplementary
+means. But whenever two suspected duplicates of measurements, bodily
+marks, photographs and finger prints have to be compared, the lineations
+of the finger prints would give an incomparably more trustworthy answer to
+the question, whether or no the suspicion of their referring to the same
+person was justified, than all the rest put together. Besides this, while
+measurements and photographs are serviceable only for adults, and even
+then under restrictions, the finger prints are available throughout life.
+It seems difficult to believe, now that their variety and persistence have
+been proved, the means of classifying them worked out, and the method of
+rapidly obtaining clear finger prints largely practised at my laboratory
+and elsewhere, that our criminal administration can long neglect the use
+of such a powerful auxiliary. It requires no higher skill and judgment to
+make, register, and hunt out finger prints, than is to be found in
+abundance among ordinary clerks. Of course some practice is required
+before facility can be gained in reading and recognising them, but not a
+few persons of whom I have knowledge, have interested themselves in doing
+so, and found no difficulty.
+
+The eleventh chapter treats of Heredity, and affirmatively answers the
+question whether patterns are transmissible by descent. The inquiry proved
+more troublesome than was expected, on account of the great variety in
+patterns and the consequent rarity with which the same pattern, other than
+the common Loop, can be expected to appear in relatives. The available
+data having been attacked both by the Arch-Loop-Whorl method, and by a
+much more elaborate system of classification--described and figured as the
+C system, the resemblances between children of either sex, of the same
+parents (or more briefly "fraternal" resemblances, as they are here
+called, for want of a better term), have been tabulated and discussed. A
+batch of twins have also been analysed. Then cases have been treated in
+which both parents had the same pattern on corresponding fingers; this
+pattern was compared with the pattern on the corresponding finger of the
+child. In these and other ways, results were obtained, all testifying to
+the conspicuous effect of heredity, and giving results that can be
+measured on the centesimal scale already described. But though the
+qualitative results are clear, the quantitative are as yet not well
+defined, and that part of the inquiry must lie over until a future time,
+when I shall have more data and when certain foreseen improvements in the
+method of work may perhaps be carried out. There is a decided appearance,
+first observed by Mr. F. Howard Collins, of whom I shall again have to
+speak, of the influence of the mother being stronger than that of the
+father, in transmitting these patterns.
+
+In the twelfth chapter we come to a branch of the subject of which I had
+great expectations, that have been falsified, namely, their use in
+indicating Race and Temperament. I thought that any hereditary
+peculiarities would almost of necessity vary in different races, and that
+so fundamental and enduring a feature as the finger markings must in some
+way be correlated with temperament.
+
+The races I have chiefly examined are English, most of whom were of the
+upper and middle classes; the others chiefly from London board schools;
+Welsh, from the purest Welsh-speaking districts of South Wales; Jews from
+the large London schools, and Negroes from the territories of the Royal
+Niger Company. I have also a collection of Basque prints taken at Cambo,
+some twenty miles inland from Biarritz, which, although small, is large
+enough to warrant a provisional conclusion. As a first and only an
+approximately correct description, the English, Welsh, Jews, Negroes, and
+Basques, may all be spoken of as identical in the character of their
+finger prints; the same familiar patterns appearing in all of them with
+much the same degrees of frequency, the differences between groups of
+different races being not larger than those that occasionally occur
+between groups of the same race. The Jews have, however, a decidedly
+larger proportion of Whorled patterns than other races, and I should have
+been tempted to make an assertion about a peculiarity in the Negroes, had
+not one of their groups differed greatly from the rest. The task of
+examination has been laborious thus far, but it would be much more so to
+arrive with correctness at a second and closer approximation to the truth.
+It is doubtful at present whether it is worth while to pursue the subject,
+except in the case of the Hill tribes of India and a few other peculiarly
+diverse races, for the chance of discovering some characteristic and
+perhaps a more monkey-like pattern.
+
+Considerable collections of prints of persons belonging to different
+classes have been analysed, such as students in science, and students in
+arts; farm labourers; men of much culture; and the lowest idiots in the
+London district (who are all sent to Darenth Asylum), but I do not, still
+as a first approximation, find any decided difference between their finger
+prints. The ridges of artists are certainly not more delicate and close
+than those of men of quite another stamp.
+
+In Chapter XIII. the question is discussed and answered affirmatively, of
+the right of the nine fundamentally differing patterns to be considered as
+different genera; also of their more characteristic varieties to rank as
+different genera, or species, as the case may be. The chief test applied,
+respected the frequency with which the various Loops that occurred on the
+thumbs, were found to differ, in successive degrees of difference, from
+the central form of all of them; it was found to accord with the
+requirements of the well-known law of Frequency of Error, proving the
+existence of a central type, from which the departures were, in common
+phraseology, accidental. Now all the evidence in the last chapter concurs
+in showing that no sensible amount of correlation exists between any of
+the patterns on the one hand, and any of the bodily faculties or
+characteristics on the other. It would be absurd therefore to assert that
+in the struggle for existence, a person with, say, a loop on his right
+middle finger has a better chance of survival, or a better chance of early
+marriage, than one with an arch. Consequently genera and species are here
+seen to be formed without the slightest aid from either Natural or Sexual
+Selection, and these finger patterns are apparently the only peculiarity
+in which Panmixia, or the effect of promiscuous marriages, admits of being
+studied on a large scale. The result of Panmixia in finger markings,
+corroborates the arguments I have used in _Natural Inheritance_ and
+elsewhere, to show that "organic stability" is the primary factor by which
+the distinctions between genera are maintained; consequently, the progress
+of evolution is not a smooth and uniform progression, but one that
+proceeds by jerks, through successive "sports" (as they are called), some
+of them implying considerable organic changes, and each in its turn being
+favoured by Natural Selection.
+
+The same word "variation" has been indiscriminately applied to two very
+different conceptions, which ought to be clearly distinguished; the one is
+that of the "sports" just alluded to, which are changes in the position of
+organic stability, and may, through the aid of Natural Selection, become
+fresh steps in the onward course of evolution; the other is that of the
+Variations proper, which are merely strained conditions of a stable form
+of organisation, and not in any way an overthrow of them. Sports do not
+blend freely together; variations proper do so. Natural Selection acts
+upon variations proper, just as it does upon sports, by preserving the
+best to become parents, and eliminating the worst, but its action upon
+mere variations can, as I conceive, be of no permanent value to evolution,
+because there is a constant tendency in the offspring to "regress" towards
+the parental type. The amount and results of this tendency have been
+fully established in _Natural Inheritance_. It is there shown, that after
+a certain departure from the central typical form has been reached in any
+race, a further departure becomes impossible without the aid of these
+sports. In the successive generations of such a population, the average
+tendency of filial regression towards the racial centre must at length
+counterbalance the effects of filial dispersion; consequently the best of
+the produce cannot advance beyond the level already attained by the
+parents, the rest falling short of it in various degrees.
+
+ * * * * *
+
+In concluding these introductory remarks, I have to perform the grateful
+duty of acknowledging my indebtedness to Mr. F. Howard Collins, who
+materially helped me during the past year. He undertook the numerous and
+tedious tabulations upon which the chapters on Heredity, and on Races and
+Classes, are founded, and he thoroughly revised nearly the whole of my
+MS., to the great advantage of the reader of this book.
+
+
+
+
+CHAPTER II
+
+PREVIOUS USE OF FINGER PRINTS
+
+
+The employment of impressions of the hand or fingers to serve as
+sign-manuals will probably be found in every nation of importance, but the
+significance attached to them differs. It ranges from a mere superstition
+that personal contact is important, up to the conviction of which this
+book will furnish assurance, that when they are properly made, they are
+incomparably the most sure and unchanging of all forms of signature. The
+existence of the superstitious basis is easily noted in children and the
+uneducated; it occupies a prominent place in the witchcrafts of
+barbarians. The modern witness who swears on the Bible, is made to hold it
+and afterwards to kiss it; he who signs a document, touches a seal or
+wafer, and declares that "this is my act and deed." Students of the
+primitive customs of mankind find abundant instances of the belief, that
+personal contact communicates some mysterious essence from the thing
+touched to the person who touches it, and _vice versa_; but it is
+unnecessary here to enter further into these elementary human reasonings,
+which are fully described and discussed by various well-known writers.
+
+The next grade of significance attached to an impression resembles that
+which commends itself to the mind of a hunter who is practised in
+tracking. He notices whether a footprint he happens to light upon, is
+larger or smaller, broader or narrower, or otherwise differs from the
+average, in any special peculiarity; he thence draws his inferences as to
+the individual who made it. So, when a chief presses his hand smeared with
+blood or grime, upon a clean surface, a mark is left in some degree
+characteristic of him. It may be that of a broad stumpy hand, or of a long
+thin one; it may be large or small; it may even show lines corresponding
+to the principal creases of the palm. Such hand prints have been made and
+repeated in many semi-civilised nations, and have even been impressed in
+vermilion on their State documents, as formerly by the sovereign of Japan.
+Though mere smudges, they serve in a slight degree to individualise the
+signer, while they are more or less clothed with the superstitious
+attributes of personal contact. So far as I can learn, no higher form of
+finger printing than this has ever existed, in regular and well-understood
+use, in any barbarous or semi-civilised nation. The ridges dealt with in
+this book could not be seen at all in such rude prints, much less could
+they be utilised as strictly distinctive features. It is possible that
+when impressions of the fingers have been made in wax, and used as seals
+to documents, they may sometimes have been subjected to minute scrutiny;
+but no account has yet reached me of trials in any of their courts of law,
+about disputed signatures, in which the identity of the party who was said
+to have signed with his finger print, had been established or disproved by
+comparing it with a print made by him then and there. The reader need be
+troubled with only a few examples, taken out of a considerable collection
+of extracts from books and letters, in which prints, or rather daubs of
+the above kind, are mentioned.
+
+A good instance of their small real value may be seen in the _Trans. China
+Branch of the Royal Asiatic Society_, Part 1, 1847, published at
+Hong-Kong, which contains a paper on "Land Tenure in China," by T. Meadows
+Taylor, with a deed concerning a sale of land, in facsimile, and its
+translation: this ends, "The mother and the son, the sellers, have in the
+presence of all the parties, received the price of the land in full,
+amounting to sixty-four taels and five mace, in perfect dollars weighed in
+scales. _Impression of the finger of the mother, of the maiden name of
+Chin._" The impression, as it appears in the woodcut, is roundish in
+outline, and was therefore made by the tip and not the bulb of the finger.
+Its surface is somewhat mottled, but there is no trace of any ridges.
+
+The native clerks of Bengal give the name of _tipsahi_ to the mark
+impressed by illiterate persons who, refusing to make either a X or their
+caste-mark, dip their finger into the ink-pot and touch the document. The
+tipsahi is not supposed to individualise the signer, it is merely a
+personal ceremony performed in the presence of witnesses.
+
+
+[Illustration: PLATE 1.
+
+FIG. 1. Chinese Coin, Tang Dynasty, about 618 A.D., with nail mark of the
+Empress Wen-teh, figured in relief.
+
+FIG. 2. Order on a Camp Sutler, by the officer of a surveying party in New
+Mexico. 1882.]
+
+
+Many impressions of fingers are found on ancient pottery, as on Roman
+tiles; indeed the Latin word _palmatus_ is said to mean an impression in
+soft clay, such as a mark upon a wall, stamped by a blow with the palm.
+Nail-marks are used ornamentally by potters of various nations. They exist
+on Assyrian bricks as signatures; for instance, in the Assyrian room of
+the British Museum, on the west side of the case C 43, one of these bricks
+contains a notice of sale and is prefaced by words that were translated
+for me thus: "Nail-mark of Nabu-sum-usur, the seller of the field, (used)
+like his seal." A somewhat amusing incident affected the design of the
+Chinese money during the great Tang dynasty, about 618 A.D. A new and
+important issue of coinage was to be introduced, and the Secretary of the
+Censors himself moulded the design in wax, and humbly submitted it to the
+Empress Wen-teh for approval. She, through maladroitness, dug the end of
+her enormously long finger-nail into its face, marking it deeply as with a
+carpenter's gouge. The poor Secretary of the Censors, Ngeu-yang-siun, who
+deserves honour from professional courtiers, suppressing such sentiments
+as he must have felt when his work was mauled, accepted the nail-mark of
+the Empress as an interesting supplement to the design; he changed it into
+a crescent in relief, and the new coins were stamped accordingly. (See
+_Coins and Medals_, edited by Stanley Lane Poole, 1885, p. 221.) A
+drawing of one of these is given in Plate 1, Fig. 1.
+
+The European practitioners of palmistry and cheiromancy do not seem to
+have paid particular attention to the ridges with which we are concerned.
+A correspondent of the American Journal _Science_, viii. 166, states,
+however, that the Chinese class the striae at the ends of the fingers into
+"pots" when arranged in a coil, and into "hooks." They are also regarded
+by the cheiromantists in Japan. A curious account has reached me of
+negroes in the United States who, laying great stress on the possession of
+finger prints in wax or dough for witchcraft purposes, are also said to
+examine their striae.
+
+Leaving Purkenje to be spoken of in a later chapter, because he deals
+chiefly with classification, the first well-known person who appears to
+have studied the lineations of the ridges as a means of identification,
+was Bewick, who made an impression of his own thumb on a block of wood and
+engraved it, as well as an impression of a finger. They were used as
+fanciful designs for his illustrated books. Occasional instances of
+careful study may also be noted, such as that of Mr. Fauld (_Nature_,
+xxii. p. 605, Oct. 28, 1880), who seems to have taken much pains, and that
+of Mr. Tabor, the eminent photographer of San Francisco, who, noticing the
+lineations of a print that he had accidentally made with his own inked
+finger upon a blotting-paper, experimented further, and finally proposed
+the method of finger prints for the registration of Chinese, whose
+identification has always been a difficulty, and was giving a great deal
+of trouble at that particular time; but his proposal dropped through.
+Again Mr. Gilbert Thompson, an American geologist, when on Government duty
+in 1882 in the wild parts of New Mexico, paid the members of his party by
+order of the camp sutler. To guard against forgery he signed his name
+across the impression made by his finger upon the order, after first
+pressing it on his office pad. He was good enough to send me the duplicate
+of one of these cheques made out in favour of a man who bore the ominous
+name of "Lying Bob" (Plate 1, Fig. 2). The impression took the place of
+the scroll work on an ordinary cheque; it was in violet aniline ink, and
+looked decidedly pretty. From time to time sporadic instances like these
+are met with, but none are comparable in importance to the regular and
+official employment made of finger prints by Sir William Herschel, during
+more than a quarter of a century in Bengal. I was exceedingly obliged to
+him for much valuable information when first commencing this study, and
+have been almost wholly indebted to his kindness for the materials used in
+this book for proving the persistence of the lineations throughout life.
+
+Sir William Herschel has presented me with one of the two original
+"Contracts" in Bengali, dated 1858, which suggested to his mind the idea
+of using this method of identification. It was so difficult to obtain
+credence to the signatures of the natives, that he thought he would use
+the signature of the hand itself, chiefly with the intention of
+frightening the man who made it from afterwards denying his formal act;
+however, the impression proved so good that Sir W. Herschel became
+convinced that the same method might be further utilised. He finally
+introduced the use of finger prints in several departments at Hooghly in
+1877, after seventeen years' experience of the value of the evidence they
+afforded. A too brief account of his work was given by him in _Nature_,
+xxiii. p. 23 (Nov. 25, 1880). He mentions there that he had been taking
+finger marks as sign-manuals for more than twenty years, and had
+introduced them for practical purposes in several ways in India with
+marked benefit. They rendered attempts to repudiate signatures quite
+hopeless. Finger prints were taken of Pensioners to prevent their
+personation by others after their death; they were used in the office for
+Registration of Deeds, and at a gaol where each prisoner had to sign with
+his finger. By comparing the prints of persons then living, with their
+prints taken twenty years previously, he considered he had proved that the
+lapse of at least that period made no change sufficient to affect the
+utility of the plan. He informs me that he submitted, in 1877, a report in
+semi-official form to the Inspector-General of Gaols, asking to be allowed
+to extend the process; but no result followed. In 1881, at the request of
+the Governor of the gaol at Greenwich (Sydney), he sent a description of
+the method, but no further steps appear to have been taken there.
+
+If the use of finger prints ever becomes of general importance, Sir
+William Herschel must be regarded as the first who devised a feasible
+method for regular use, and afterwards officially adopted it. His method
+of printing for those purposes will be found in the next chapter.
+
+
+
+
+CHAPTER III
+
+METHODS OF PRINTING
+
+
+It will be the aim of this chapter to show how to make really good and
+permanent impressions of the fingers. It is very easy to do so when the
+principles of the art are understood and practised, but difficult
+otherwise.
+
+One example of the ease of making good, but not permanent impressions, is
+found, and should be tried, by pressing the bulb of a finger against
+well-polished glass, or against the highly-polished blade of a razor. The
+finger must be _very slightly_ oiled, as by passing it through the hair;
+if it be moist, dry it with a handkerchief before the oiling. Then press
+the bulb of the finger on the glass or razor, as the case may be, and a
+beautiful impression will be left. The hardness of the glass or steel
+prevents its surface from rising into the furrows under the pressure of
+the ridges, while the layer of oil which covers the bottom of the furrows
+is too thin to reach down to the glass or steel; consequently the ridges
+alone are printed. There is no capillary or other action to spread the
+oil, so the impression remains distinct. A merely moist and not oily
+finger leaves a similar mark, but it soon evaporates.
+
+This simple method is often convenient for quickly noting the character of
+a finger pattern. The impression may be made on a window-pane, a
+watch-glass, or even an eye-glass, if nothing better is at hand. The
+impression is not seen to its fullest advantage except by means of a
+single small source of bright light. The glass or steel has to be so
+inclined as just _not_ to reflect the light into the eye. That part of the
+light which falls on the oily impression is not so sharply reflected from
+it as from the surface of the glass or steel. Consequently some stray
+beams of the light which is scattered from the oil, reach the eye, while
+all of the light reflected from the highly-polished glass or steel passes
+in another direction and is unseen. The result is a brilliantly luminous
+impression on a dark background. The impression ceases to be visible when
+the glass or steel is not well polished, and itself scatters the light,
+like the oil.
+
+There are two diametrically opposed methods of printing, each being the
+complement of the other. The method used in ordinary printing, is to ink
+the projecting surfaces only, leaving the depressed parts clean. The other
+method, used in printing from engraved plates, is to ink the whole
+surface, and then to clean the ink from the projecting parts, leaving the
+depressions only filled with it. Either of these two courses can be
+adopted in taking finger prints, but not the two together, for when they
+are combined in equal degrees the result must be a plain black blot.
+
+The following explanations will be almost entirely confined to the first
+method, namely, that of ordinary printing, as the second method has so far
+not given equally good results.
+
+The ink used may be either printer's ink or water colour, but for
+producing the best work, rapidly and on a large scale, the method of
+printer's ink seems in every respect preferable. However, water colour
+suffices for some purposes, and as there is so much convenience in a pad,
+drenched with dye, such as is commonly used for hand stamps, and which is
+always ready for use, many may prefer it. The processes with printer's ink
+will be described first.
+
+The relief formed by the ridges is low. In the fingers of very young
+children, and of some ladies whose hands are rarely submitted to rough
+usage, the ridges are exceptionally faint; their crests hardly rise above
+the furrows, yet it is the crests only that are to be inked. Consequently
+the layer of ink on the slab or pad on which the finger is pressed for the
+purpose of blackening it, must be _very thin_. Its thickness must be less
+than half the elevation of the ridges, for when the finger is pressed
+down, the crests displace the ink immediately below them, and drives it
+upwards into the furrows which would otherwise be choked with it.
+
+It is no violent misuse of metaphor to compare the ridges to the crests of
+mountain ranges, and the depth of the blackening that they ought to
+receive, to that of the newly-fallen snow upon the mountaintops in the
+early autumn, when it powders them from above downwards to a
+sharply-defined level. The most desirable blackening of the fingers
+corresponds to a snowfall which covers all the higher passes, but descends
+no lower.
+
+With a finger so inked it is scarcely possible to fail in making a good
+imprint; the heaviest pressure cannot spoil it. The first desideratum is,
+then, to cover the slab by means of which the finger is to be blackened,
+with an extremely thin layer of ink.
+
+This cannot be accomplished with printer's ink unless the slab is very
+clean, the ink somewhat fluid, and the roller that is used to spread it,
+in good condition. When a plate of glass is used for the slab, it is easy,
+by holding the inked slab between the eye and the light, to judge of the
+correct amount of inking. It should appear by no means black, but of a
+somewhat light brown.
+
+The thickness of ink transferred by the finger to the paper is much less
+than that which lay upon the slab. The ink adheres to the slab as well as
+to the finger; when they are separated, only a portion of the ink is
+removed by the finger. Again, when the inked finger is pressed on the
+paper, only a portion of the ink that was on the finger is transferred to
+the paper. Owing to this double reduction, it seldom happens that a clear
+impression is at the same time black. An ideally perfect material for
+blackening would lie loosely on the slab like dust, it would cling very
+lightly to the finger, but adhere firmly to the paper.
+
+The last preliminary to be noticed is the slowness with which the
+printer's ink hardens on the slab, and the rapidity with which it dries on
+paper. While serviceable for hours in the former case, in the latter it
+will be dry in a very few seconds. The drying or hardening of this oily
+ink has nothing whatever to do with the loss of moisture in the ordinary
+sense of the word, that is to say, of the loss of the contained water: it
+is wholly due to oxidisation of the oil. An extremely thin oxidised film
+soon forms on the surface of the layer on the slab, and this shields the
+lower-lying portions of the layer from the air, and retards further
+oxidisation. But paper is very unlike a polished slab; it is a fine felt,
+full of minute interstices. When a printed period (.) is placed under the
+microscope it looks like a drop of tar in the middle of a clean
+bird's-nest. The ink is minutely divided among the interstices of the
+paper, and a large surface being thereby exposed to the air, it oxidises
+at once, while a print from the finger upon glass will not dry for two or
+three days. One effect of oxidisation is to give a granulated appearance
+to the ink on rollers which have been allowed to get dirty. This
+granulation leaves clots on the slab which are fatal to good work:
+whenever they are seen, the roller must be cleaned at once.
+
+The best ink for finger printing is not the best for ordinary printing. It
+is important to a commercial printer that his ink should dry rapidly on
+the paper, and he does not want a particularly thin layer of it;
+consequently, he prefers ink that contains various drying materials, such
+as litharge, which easily part with their oxygen. In finger prints this
+rapid drying is unnecessary, and the drying materials do harm by making
+the ink too stiff. The most serviceable ink for our purpose is made of any
+pure "drying" oil (or oil that oxidises rapidly), mixed with lampblack and
+very little else. I get mine in small collapsible tubes, each holding
+about a quarter of an ounce, from Messrs. Reeve & Sons, 113 Cheapside,
+London, W.C. Some thousands of fingers may be printed from the contents of
+one of these little tubes.
+
+Let us now pass on to descriptions of printing apparatus. First, of that
+in regular use at my anthropometric laboratory at South Kensington, which
+has acted perfectly for three years; then of a similar but small apparatus
+convenient to carry about or send abroad, and of temporary arrangements in
+case any part of it may fail. Then lithographic printing will be noticed.
+In all these cases some kind of printer's ink has to be used. Next, smoke
+prints will be described, which at times are very serviceable; after this
+the methods of water colours and aniline dyes; then casts of various
+kinds; last of all, enlargements.
+
+_Laboratory apparatus._--Mine consists of: 1, slab; 2, roller; 3, bottle
+of benzole (paraffin, turpentine, or solution of washing soda); 4, a
+funnel, with blotting-paper to act as a filter; 5, printer's ink; 6, rags
+and duster; 7, a small glass dish; 8, cards to print on.
+
+The _Slab_ is a sheet of polished copper, 10-1/2 inches by 7, and about
+1/16 inch thick, mounted on a solid board 3/4 inch thick, with projecting
+ears for ease of handling. The whole weighs 2-1/2 lbs. Each day it is
+cleaned with the benzole and left bright. [A slab of more than double the
+length and less than half the width might, as my assistant thinks, answer
+better.]
+
+The _Roller_ is an ordinary small-sized printer's roller, 6 inches long
+and 3 in diameter, obtained from Messrs. Harrild, 25 Farringdon Street,
+London. Mine remained in good condition for quite a year and a half. When
+it is worn the maker exchanges it for a new one at a trifling cost. A good
+roller is of the highest importance; it affords the only means of
+spreading ink evenly and thinly, and with quickness and precision, over a
+large surface. The ingenuity of printers during more than four centuries
+in all civilised nations, has been directed to invent the most suitable
+composition for rollers, with the result that particular mixtures of glue,
+treacle, etc., are now in general use, the proportions between the
+ingredients differing according to the temperature at which the roller is
+intended to be used. The roller, like the slab, is cleansed with benzole
+every day (a very rapid process) and then put out of the reach of dust.
+Its clean surface is smooth and shining.
+
+The _Benzole_ is kept in a pint bottle. Sometimes paraffin or turpentine
+has been used instead; washing soda does not smell, but it dissolves the
+ink more slowly. They are otherwise nearly equally effective in cleansing
+the rollers and fingers. When dirty, the benzole can be rudely filtered
+and used again.
+
+The _Funnel_ holds blotting-paper for filtering the benzole. Where much
+printing is going on, and consequent washing of hands, it is worth while
+to use a filter, as it saves a little daily expense, though benzole is
+very cheap, and a few drops of it will clean a large surface.
+
+The _Ink_ has already been spoken of. The more fluid it is the better, so
+long as it does not "run." A thick ink cannot be so thinned by adding
+turpentine, etc., as to make it equal to ink that was originally fluid.
+The variety of oils used in making ink, and of the added materials, is
+endless. For our purpose, any oil that dries and does not spread, such as
+boiled or burnt linseed oil, mixed with lampblack, is almost all that is
+wanted. The burnt oil is the thicker of the two, and dries the faster.
+Unfortunately the two terms, burnt and boiled linseed oil, have no
+definite meaning in the trade, boiling or burning not being the simple
+processes these words express, but including an admixture of drying
+materials, which differ with each manufacturer; moreover, there are two,
+if not three, fundamentally distinct qualities of linseed, in respect to
+the oil extracted from it. The ink used in the laboratory and described
+above, answers all requirements. Many other inks have suited less well;
+less even than that which can be made, in a very homely way, with a little
+soot off a plate that had been smoked over a candle, mixed with such
+boiled linseed oil as can be bought at unpretentious oil and colour shops,
+its only fault being a tendency to run.
+
+_Rags_, and a comparatively clean duster, are wanted for cleaning the slab
+and roller, without scratching them.
+
+The small _Glass Dish_ holds the benzole, into which the inked fingers are
+dipped before wiping them with the duster. Soap and water complete the
+preliminary cleansing.
+
+_Cards_, lying flat, and being more easily manipulated than paper, are now
+used at the laboratory for receiving the impressions. They are of rather
+large size, 11-1/2 x 5 inches, to enable the prints of the ten digits to
+be taken on the same card in two rather different ways (see Plate 2, Fig.
+3), and to afford space for writing notes. The cards must have a smooth
+and yet slightly absorbent surface. If too highly glazed they cease to
+absorb, and more ink will remain on the fingers and less be transferred
+from them to the paper. A little trial soon determines the best specimen
+from among a few likely alternatives. "Correspondence cards" are suitable
+for taking prints of not more than three fingers, and are occasionally
+employed in the laboratory. Paper books and pads were tried, but their
+surfaces are inferior to cards in flatness, and their use is now
+abandoned.
+
+The cards should be _very_ white, because, if a photographic enlargement
+should at any time be desired, a slight tint on the card will be an
+impediment to making a photograph that shall be as sharp in its lines as
+an engraving, it being recollected that the cleanest prints are brown, and
+therefore not many shades darker than the tints of ordinary cards.
+
+The method of printing at the laboratory is to squeeze a drop or so of ink
+on to the slab, and to work it thoroughly with the roller until a thin and
+even layer is spread, just as is done by printers, from one of whom a
+beginner might well purchase a lesson. The thickness of the layer of ink
+is tested from time to time by taking a print of a finger, and comparing
+its clearness and blackness with that of a standard print, hung up for the
+purpose close at hand. If too much ink has been put on the slab, some of
+it must be cleaned off, and the slab rolled afresh with what remains on it
+and on the roller. But this fault should seldom be committed; little ink
+should be put on at first, and more added little by little, until the
+required result is attained.
+
+The right hand of the subject, which should be quite passive, is taken by
+the operator, and the bulbs of his four fingers laid flat on the inked
+slab and pressed gently but firmly on it by the flattened hand of the
+operator. Then the inked fingers are laid flat upon the upper part of the
+right-hand side of the card (Plate 2, Fig. 3), and pressed down gently and
+firmly, just as before, by the flattened hand of the operator. This
+completes the process for one set of prints of the four fingers of the
+right hand. Then the bulb of the thumb is slightly _rolled_ on the inked
+slab, and again on the lower part of the card, which gives a more extended
+but not quite so sharp an impression. Each of the four fingers of the same
+hand, in succession, is similarly rolled and impressed. This completes the
+process for the second set of prints of the digits of the right hand. Then
+the left hand is treated in the same way.
+
+The result is indicated by the diagram, which shows on what parts of the
+card the impressions fall. Thus each of the four fingers is impressed
+twice, once above with a simple dab, and once below with a rolled
+impression, but each thumb is only impressed once; the thumbs being more
+troublesome to print from than fingers. Besides, the cards would have to
+be made even larger than they are, if two impressions of each thumb had to
+be included. It takes from two and a half to three minutes to obtain the
+eighteen impressions that are made on each card.
+
+The _pocket apparatus_ is similar to one originally made and used by Sir
+William J. Herschel (see Plate 3, Fig. 4, in which the roller and its
+bearings are drawn of the same size as those I use). A small cylinder of
+hard wood, or of brass tube, say 1-3/4 inch long, and 1/2 or 3/4 inch in
+diameter, has a pin firmly driven into each end to serve as an axle. A
+piece of tightly-fitting india-rubber tubing is drawn over the cylinder.
+The cylinder, thus coated with a soft smooth compressible material, turns
+on its axle in two brackets, each secured by screws, as shown in Plate 2,
+Fig. 4, to a board (say 6 x 2-1/2 x 1/4 inch) that serves as handle. This
+makes a very fair and durable roller; it can be used in the heat and damp
+of the tropics, and is none the worse for a wetting, but it is by no means
+so good for delicate work as a cylinder covered with roller composition.
+These are not at all difficult to make; I have cast them for myself. The
+mould is a piece of brass tube, polished inside. A thick disc, with a
+central hole for the lower pin of the cylinder, fits smoothly into the
+lower end of the mould, and a ring with a thin bar across it, fits over
+the other end, the upper pin of the cylinder entering a hole in the middle
+of the bar; thus the cylinder is firmly held in the right position. After
+slightly oiling the inside of the mould, warming it, inserting the disc
+and cylinder, and fitting on the ring, the melted composition is poured in
+on either side of the bar. As it contracts on cooling, rather more must be
+poured in than at first appears necessary. Finally the roller is pushed
+out of the mould by a wooden ramrod, applied to the bottom of the disc.
+The composition must be melted like glue, in a vessel surrounded by hot
+water, which should never be allowed to boil; otherwise it will be spoilt.
+Harrild's best composition is more than twice the cost of that ordinarily
+used, and is expensive for large rollers, but for these miniature ones the
+cost is unimportant. The mould with which my first roller was made, was an
+old pewter squirt with the nozzle cut off; its piston served the double
+purpose of disc and ramrod.
+
+The _Slab_ is a piece of thick plate glass, of the same length and width
+as the handle to the roller, so they pack up easily together; its edges
+are ground to save the fingers and roller alike from being cut. (Porcelain
+takes the ink better than glass, but is not to be commonly found in the
+shops, of a convenient shape and size; a glazed tile makes a capital
+slab.) A collapsible tube of printer's ink, a few rags, and a phial of
+washing soda, complete the equipment (benzole may spoil india-rubber).
+When using the apparatus, spread a newspaper on the table to prevent
+accident, have other pieces of newspaper ready to clean the roller, and to
+remove any surplus of ink from it by the simple process of rolling it on
+the paper. Take care that the washing soda is in such a position that it
+cannot be upset and ruin the polish of the table. With these precautions,
+the apparatus may be used with cleanliness even in a drawing-room. The
+roller is of course laid on its back when not in use.
+
+My assistant has taken good prints of the three first fingers of the right
+hands of more than 300 school children, say 1000 fingers, in a few hours
+during the same day, by this apparatus. Hawksley, 357 Oxford Street, W.,
+sells a neatly fitted-up box with all the necessary apparatus.
+
+_Rougher arrangements._--A small ball made by tying chamois leather round
+soft rags, may be used in the absence of a roller. The fingers are inked
+from the ball, over which the ink has been evenly distributed, by dabbing
+it many times against a slab or plate. This method gives good results, but
+is slow; it would be intolerably tedious to employ it on a large scale, on
+all ten digits of many persons.
+
+It is often desirable to obtain finger prints from persons at a distance,
+who could not be expected to trouble themselves to acquire the art of
+printing for the purpose of making a single finger print. On these
+occasions I send folding-cases to them, each consisting of two pieces of
+thin copper sheeting, fastened side by side to a slip of pasteboard, by
+bending the edges of the copper over it. The pasteboard is half cut
+through at the back, along the space between the copper sheets, so that
+it can be folded like a reply post-card, the copper sheets being thus
+brought face to face, but prevented from touching by the margin of an
+interposed card, out of which the middle has been cut away. The two pieces
+of copper being inked and folded up, may then be sent by post. On arrival
+the ink is fresh, and the folders can be used as ordinary inked slabs.
+(See also Smoke Printing, page 47.)
+
+The fluidity of even a very thin layer of ink seems to be retained for an
+indefinite time if the air is excluded to prevent oxidisation. I made
+experiments, and found that if pieces of glass (photographic quarter
+plates) be inked, and placed face to face, separated only by narrow paper
+margins, and then wrapped up without other precaution, they will remain
+good for a year and a half.
+
+A slight film of oxidisation on the surface of the ink is a merit, not a
+harm; it is cleaner to work with and gives a blacker print, because the
+ink clings less tenaciously to the finger, consequently more of it is
+transferred to the paper.
+
+If a blackened plate becomes dry, and is re-inked without first being
+cleaned, the new ink will rob the old of some of its oxygen and it will
+become dry in a day or even less.
+
+_Lithography._--Prints may be made on "transfer-paper," and thence
+transferred to stone. It is better not to impress the fingers directly
+upon the stone, as the print from the stone would be reversed as compared
+with the original impression, and mistakes are likely to arise in
+consequence. The print is re-reversed, or put right, by impressing the
+fingers on transfer-paper. It might sometimes be desirable to obtain
+rapidly a large number of impressions of the finger prints of a suspected
+person. In this case lithography would be easier, quicker, and cheaper
+than photography.
+
+_Water Colours and Dyes._--The pads most commonly used with office stamps
+are made of variously prepared gelatine, covered with fine silk to protect
+the surface, and saturated with an aniline dye. If the surface be touched,
+the finger is inked, and if the circumstances are all favourable, a good
+print may be made, but there is much liability to blot. The pad remains
+ready for use during many days without any attention, fresh ink being
+added at long intervals. The advantage of a dye over an ordinary water
+colour is, that it percolates the silk without any of its colour being
+kept back; while a solution of lampblack or Indian ink, consisting of
+particles of soot suspended in water, leaves all its black particles
+behind when it is carefully filtered; only clear water then passes
+through.
+
+A serviceable pad may be made out of a few thicknesses of cloth or felt
+with fine silk or cambric stretched over it. The ink should be of a slowly
+drying sort, made, possibly, of ordinary ink, with the admixture of brown
+sugar, honey, glycerine or the like, to bring it to a proper consistence.
+
+Mr. Gilbert Thompson's results by this process have already been
+mentioned. A similar process was employed for the Bengal finger prints by
+Sir W. Herschel, who sent me the following account: "As to the printing
+of the fingers themselves, no doubt practice makes perfect. But I took no
+pains with my native officials, some dozen or so of whom learnt to do it
+quite well enough for all practical purposes from Bengali written
+instructions, and using nothing but a kind of lampblack ink made by the
+native orderly for use with the office seal." A batch of these
+impressions, which he was so good as to send me, are all clear, and in
+most cases very good indeed. It would be easier to employ this method in a
+very damp climate than in England, where a very thin layer of lampblack is
+apt to dry too quickly on the fingers.
+
+_Printing as from Engraved Plates._--Professor Ray Lankester kindly sent
+me his method of taking prints with water colours. "You take a watery
+brushful or two of the paint and rub it over the hands, rubbing one hand
+against the other until they feel sticky. A _thin_ paper (tissue is best)
+placed on an oval cushion the shape of the hand, should be ready, and the
+hand pressed not too firmly on to it. I enclose a rough sample, done
+without a cushion. You require a cushion for the hollow of the hand, and
+the paint must be rubbed by the two hands until they feel sticky, not
+watery." This is the process of printing from engravings, the ink being
+removed from the ridges, and lying in the furrows. Blood can be used in
+the same way.
+
+The following is extracted from an article by Dr. Louis Robinson in the
+_Nineteenth Century_, May 1892, p. 303:--
+
+ "I found that direct prints of the infant's feet on paper would answer
+ much better [than photography]. After trying various methods I found
+ that the best results could be got by covering the foot by means of a
+ soft stencil brush with a composition of lampblack, soap, syrup, and
+ blue-black ink; wiping it gently from heel to toe with a
+ smoothly-folded silk handkerchief to remove the superfluous pigment,
+ and then applying a moderately flexible paper, supported on a soft
+ pad, direct to the foot."
+
+A curious method with paper and ordinary writing ink, lately contrived by
+Dr. Forgeot, is analogous to lithography. He has described in one of the
+many interesting pamphlets published by the "Laboratoire d'Anthropologie
+Criminelle" of Lyon (_Stenheil_, 2 Rue Casimir-Delavigne, Paris), his new
+process of rendering visible the previously invisible details of such
+faint finger prints as thieves may have left on anything they have
+handled, the object being to show how evidence may sometimes be obtained
+for their identification. It is well known that pressure of the hand on
+the polished surface of glass or metal leaves a latent image very
+difficult to destroy, and which may be rendered visible by suitable
+applications, but few probably have suspected that this may be the case,
+to a considerable degree, with ordinary paper. Dr. Forgeot has shown that
+if a slightly greasy hand, such for example as a hand that has just been
+passed through the hair, be pressed on clean paper, and if common ink be
+afterwards brushed lightly over the paper, it will refuse to lie thickly
+on the greasy parts, and that the result will be a very fair picture of
+the minute markings on the fingers. He has even used these productions as
+negatives, and printed good photographs from them. He has also sent me a
+photographic print made from a piece of glass which had been exposed to
+the vapour of hydrofluoric acid, after having been touched by a greasy
+hand. I have made many trials of his method with considerable success. It
+affords a way of obtaining serviceable impressions in the absence of
+better means. Dr. Forgeot's pamphlet describes other methods of a
+generally similar kind, which he has found to be less good than the above.
+
+_Smoke Printing._--When other apparatus is not at hand, a method of
+obtaining very clear impressions is to smoke a plate over a lighted
+candle, to press the finger on the blackened surface, and then on an
+adhesive one. The following details must, however, be borne in mind: the
+plate must not be smoked too much, for the same reason that a slab must
+not be inked too much; and the adhesive surface must be only slightly
+damped, not wetted, or the impression will be blurred. A crockery plate is
+better than glass or metal, as the soot does not adhere to it so tightly,
+and it is less liable to crack. Professor Bowditch finds mica (which is
+sold at photographic stores in small sheets) to be the best material.
+Certainly the smoke comes wholly off the mica on to the parts of the
+finger that touch it, and a beautiful negative is left behind, which can
+be utilised in the camera better than glass that has been similarly
+treated; but it does not serve so well for a plate that is intended to be
+kept ready for use in a pocket-book, its softness rendering it too liable
+to be scratched. I prefer to keep a slip of very thin copper sheeting in
+my pocket-book, with which, and with the gummed back of a postage stamp,
+or even the gummed fringe to a sheet of stamps, impressions can easily be
+taken. The thin copper quickly cools, and a wax match supplies enough
+smoke. The folders spoken of (p. 42) may be smoked instead of being inked,
+and are in some cases preferable to carry in the pocket or to send by
+post, being so easy to smoke afresh. Luggage labels that are thickly
+gummed at the back furnish a good adhesive surface. The fault of gummed
+paper lies in the difficulty of damping it without its curling up. The
+gummed paper sold by stationers is usually thinner than luggage labels,
+and still more difficult to keep flat. Paste rubbed in a very thin layer
+over a card makes a surface that holds soot firmly, and one that will not
+stick to other surfaces if accidentally moistened. Glue, isinglass, size,
+and mucilage, are all suitable. It was my fortune as a boy to receive
+rudimentary lessons in drawing from a humble and rather grotesque master.
+He confided to me the discovery, which he claimed as his own, that pencil
+drawings could be fixed by licking them; and as I write these words, the
+image of his broad swab-like tongue performing the operation, and of his
+proud eyes gleaming over the drawing he was operating on, come vividly to
+remembrance. This reminiscence led me to try whether licking a piece of
+paper would give it a sufficiently adhesive surface. It did so. Nay, it
+led me a step further, for I took two pieces of paper and licked both.
+The dry side of the one was held over the candle as an equivalent to a
+plate for collecting soot, being saved by the moisture at the back from
+igniting (it had to be licked two or three times during the process), and
+the impression was made on the other bit of paper. An ingenious person
+determined to succeed in obtaining the record of a finger impression, can
+hardly fail altogether under any ordinary circumstances.
+
+Physiologists who are familiar with the revolving cylinder covered with
+highly-glazed paper, which is smoked, and then used for the purpose of
+recording the delicate movements of a tracer, will have noticed the beauty
+of the impression sometimes left by a finger that had accidentally touched
+it. They are also well versed in the art of varnishing such impressions to
+preserve them in a durable form.
+
+A cake of blacklead (plumbago), such as is sold for blackening grates,
+when rubbed on paper leaves a powdery surface that readily blackens the
+fingers, and shows the ridges distinctly. A small part of the black comes
+off when the fingers are pressed on sticky paper, but I find it difficult
+to ensure good prints. The cakes are convenient to carry and cleanly to
+handle. Whitening, and still more, whitening mixed with size, may be used
+in the same way, but it gathers in the furrows, not on the ridges.
+
+_Casts_ give undoubtedly the most exact representation of the ridges, but
+they are difficult and unsatisfactory to examine, puzzling the eye by
+showing too conspicuously the variation of their heights, whereas we only
+want to know their courses. Again, as casts must be of a uniform colour,
+the finer lines are indistinctly seen except in a particular light.
+Lastly, they are both cumbrous to preserve and easily broken.
+
+A sealing-wax impression is the simplest and best kind of cast, and the
+finger need not be burnt in making it. The plan is to make a considerable
+pool of flaming sealing-wax, stirring it well with the still unmelted
+piece of the stick, while it is burning. Then blow out the flame and wait
+a little, until the upper layer has cooled. Sealing-wax that has been well
+aflame takes a long time to harden thoroughly after it has parted with
+nearly all its heat. By selecting the proper moment after blowing out the
+flame, the wax will be cool enough for the finger to press it without
+discomfort, and it will still be sufficiently soft to take a sharp
+impression. Dentist's wax, which is far less brittle, is easily worked,
+and takes impressions that are nearly as sharp as those of sealing-wax; it
+has to be well heated and kneaded, then plunged for a moment in cold water
+to chill the surface, and immediately impressed. Gutta-percha can also be
+used. The most delicate of all impressions is that left upon a thick clot
+of varnish, which has been exposed to the air long enough for a thin film
+to have formed over it. The impression is transient, but lingers
+sufficiently to be easily photographed. It happened, oddly enough, that a
+few days after I had noticed this effect, and had been experimenting upon
+it, I heard an interesting memoir "On the Minute Structure of Striped
+Muscle, with special allusion to a new method of investigation by means
+of 'Impressions' stamped in Collodion," submitted to the Royal Society by
+Dr. John Berry Haycraft, in which an analogous method was used to obtain
+impressions of delicate microscopic structures.
+
+_Photographs_ are valuable in themselves, and the negatives serve for
+subsequent _enlargements_. They are unquestionably accurate, and the
+labour of making them being mechanical, may be delegated. If the print be
+in printer's ink on white paper, the process is straightforward, first of
+obtaining a negative and afterwards photo-prints from it. The importance
+of the paper or card used to receive the finger print being quite white,
+has already been pointed out. An imprint on white crockery-ware is
+beautifully clear. Some of the photographs may be advantageously printed
+by the ferro-prussiate process. The paper used for it does not curl when
+dry, its texture is good for writing on, and the blue colour of the print
+makes handwriting clearly legible, whether it be in ink or in pencil.
+
+Prints on glass have great merits for use as lantern slides, but it must
+be recollected that they may take some days to dry, and that when dry the
+ink can be only too easily detached from them by water, which insinuates
+itself between the dry ink and the glass. Of course they could be
+varnished, if the trouble and cost were no objection, and so preserved.
+The negative print left on an inked slab, after the finger has touched it,
+is sometimes very clear, that on smoked glass better, and on smoked mica
+the clearest of all. These have merely to be placed in the enlarging
+camera, where the negative image thrown on argento-bromide paper will
+yield a positive print. (See p. 90.)
+
+I have made, by hand, many enlargements with a prism (camera lucida), but
+it is difficult to enlarge more than five times by means of it. So much
+shade is cast by the head that the prism can hardly be used at a less
+distance than 3 inches from the print, or one quarter the distance (12
+inches) at which a book is usually read, while the paper on which the
+drawing is made cannot well be more than 15 inches below the prism; so it
+makes an enlargement of (4 x 15)/12 or five-fold. This is a very
+convenient method of analysing a pattern, since the lines follow only the
+axes of the ridges, as in Plate 3, Fig. 5. The prism and attached
+apparatus may be kept permanently mounted, ready for use at any time,
+without the trouble of any adjustment.
+
+An enlarging pantagraph has also been of frequent use to me, in which the
+cross-wires of a low-power microscope took the place of the pointer. It
+has many merits, but its action was not equally free in all directions;
+the enlarged traces were consequently jagged, and required subsequent
+smoothing.
+
+All hand-made enlargements are tedious to produce, as the total length of
+lineations to be followed is considerable. In a single finger print made
+by dabbing down the finger, their actual length amounts to about 18
+inches; therefore in a five-fold enlargement of the entire print the
+pencil has to be carefully directed over five times that distance, or more
+than 7 feet.
+
+Large copies of tracings made on transparent paper, either by the Camera
+Lucida or by the Pantagraph, are easily printed by the ferro-prussiate
+photographic process mentioned above, in the same way that plans are
+copied by engineers.
+
+
+
+
+CHAPTER IV
+
+THE RIDGES AND THEIR USES
+
+
+The palmar surface of the hands and the soles of the feet, both in men and
+monkeys, are covered with minute ridges that bear a superficial
+resemblance to those made on sand by wind or flowing water. They form
+systems which run in bold sweeps, though the courses of the individual
+ridges are less regular. Each ridge (Plate 3, Fig. 5) is characterised by
+numerous minute peculiarities, called _Minutiae_ in this book, here
+dividing into two, and there uniting with another (_a_, _b_), or it may
+divide and almost immediately reunite, enclosing a small circular or
+elliptical space (_c_); at other times its beginning or end is markedly
+independent (_d_, _e_); lastly, the ridge may be so short as to form a
+small island (_f_).
+
+Whenever an interspace is left between the boundaries of different systems
+of ridges, it is filled by a small system of its own, which will have some
+characteristic shape, and be called a _pattern_ in this book.
+
+
+[Illustration: PLATE 3.
+
+FIG. 5. Characteristic peculiarities in Ridges (about 8 times the natural
+size).
+
+FIG. 6. Systems of Ridges, and the Creases in the Palm.]
+
+
+There are three particularly well-marked systems of ridges in the palm of
+the hand marked in Plate 3, Fig. 6, ~1~, as Th, AB, and BC. The system Th
+is that which runs over the ball of the thumb and adjacent parts of the
+palm. It is bounded by the line _a_ which starts from the middle of the
+palm close to the wrist, and sweeps thence round the ball of the thumb to
+the edge of the palm on the side of the thumb, which it reaches about half
+an inch, more or less, below the base of the fore-finger. The system AB is
+bounded towards the thumb by the above line _a_, and towards the little
+finger by the line _b_; the latter starts from about the middle of the
+little-finger side of the palm, and emerges on the opposite side just
+below the fore-finger. Consequently, every ridge that wholly crosses the
+palm is found in AB. The system BC is bounded thumbwards by the line _b_,
+until that line arrives at a point immediately below the axis of the
+fore-finger; there the boundary of BC leaves the line _b_, and skirts the
+base of the fore-finger until it reaches the interval which separates the
+fore and middle fingers. The upper boundary of BC is the line _c_, which
+leaves the little-finger side of the palm at a small distance below the
+base of the little finger, and terminates between the fore and middle
+fingers. Other systems are found between _c_ and the middle, ring, and
+little fingers; they are somewhat more variable than those just described,
+as will be seen by comparing the five different palms shown in Fig. 6.
+
+An interesting example of the interpolation of a small and independent
+system occurs frequently in the middle of one or other of the systems AB
+or BC, at the place where the space covered by the systems of ridges
+begins to broaden out very rapidly. There are two ways in which the
+necessary supply of ridges makes its appearance, the one is by a series of
+successive embranchments (Fig. 6, ~1~), the other is by the insertion of
+an independent system, as shown in ~4~, ~5~. Another example of an
+interpolated system, but of rarer occurrence, is found in the system Th,
+on the ball of the thumb, as seen in ~2~.
+
+Far more definite in position, and complex in lineation, are the small
+independent systems which appear on the bulbs of the thumb and fingers.
+They are more instructive to study, more easy to classify, and will alone
+be discussed in this book.
+
+In the diagram of the hand, Fig. 6, ~1~, the three chief cheiromantic
+creases are indicated by dots, but are not numbered. They are made (1) by
+the flexure of the thumb, (2) of the four fingers simultaneously, and (3)
+of the middle, ring, and little fingers simultaneously, while the
+fore-finger remains extended. There is no exact accordance between the
+courses of the creases and those of the adjacent ridges, less still do the
+former agree with the boundaries of the systems. The accordance is closest
+between the crease (1) and the ridges in Th; nevertheless that crease does
+not agree with the line _a_, but usually lies considerably within it. The
+crease (2) cuts the ridges on either side, at an angle of about 30
+degrees. The crease (3) is usually parallel to the ridges between which it
+runs, but is often far from accordant with the line _c_. The creases at
+the various joints of the thumb and fingers cut the ridges at small
+angles, say, very roughly, of 15 degrees.
+
+The supposition is therefore untenable that the courses of the ridges are
+wholly determined by the flexures. It appears, however, that the courses
+of the ridges and those of the lines of flexure may be in part, but in
+part only, due to the action of the same causes.
+
+The fact of the creases of the hand being strongly marked in the
+newly-born child, has been considered by some to testify to the archaic
+and therefore important character of their origin. The crumpled condition
+of the hand of the infant, during some months before its birth, seems to
+me, however, quite sufficient to account for the creases.
+
+I possess a few specimens of hand prints of persons taken when children,
+and again, after an interval of several years: they show a general
+accordance in respect to the creases, but not sufficiently close for
+identification.
+
+The ridges on the feet and toes are less complex than those on the hands
+and digits, and are less serviceable for present purposes, though equally
+interesting to physiologists. Having given but little attention to them
+myself, they will not be again referred to.
+
+ * * * * *
+
+The ridges are studded with minute pores which are the open mouths of the
+ducts of the somewhat deeply-seated glands, whose office is to secrete
+perspiration: Plate 10, _n_, is a good example of them. The distance
+between adjacent pores on the same ridge is, roughly speaking, about half
+that which separates the ridges. The lines of a pattern are such as an
+artist would draw, if dots had been made on a sheet of paper in positions
+corresponding to the several pores, and he endeavoured to connect them by
+evenly flowing curves; it would be difficult to draw a pattern under these
+conditions, and within definite boundaries, that cannot be matched in a
+living hand.
+
+The embryological development of the ridges has been studied by many, but
+more especially by Dr. A. Kollmann,[1] whose careful investigations and
+bibliography should be consulted by physiologists interested in the
+subject. He conceives the ridges to be formed through lateral pressures
+between nascent structures.
+
+
+[Illustration: PLATE 4.
+
+FIG. 7. SCARS AND CUTS, AND THEIR EFFECTS ON THE RIDGES.
+
+FIG. 8. FORMATION OF INTERSPACE AND EXAMPLES OF THE ENCLOSED PATTERNS.]
+
+
+The ridges are said to be first discernible in the fourth month of
+foetal life, and fully formed by the sixth. In babies and children the
+delicacy of the ridges is proportionate to the smallness of their stature.
+They grow simultaneously with the general growth of the body, and continue
+to be sharply defined until old age has set in, when an incipient
+disintegration of the texture of the skin spoils, and may largely
+obliterate them, as in the finger prints on the title-page. They develop
+most in hands that do a moderate amount of work, and they are strongly
+developed in the foot, which has the hard work of supporting the weight
+of the body. They are, as already mentioned, but faintly developed in the
+hands of ladies, rendered delicate by the continual use of gloves and lack
+of manual labour, and in idiots of the lowest type who are incapable of
+labouring at all. When the skin becomes thin, the ridges simultaneously
+subside in height. They are obliterated by the callosities formed on the
+hands of labourers and artisans in many trades, by the constant pressure
+of their peculiar tools. The ridges on the side of the left fore-finger of
+tailors and seamstresses are often temporarily destroyed by the needle; an
+instance of this is given in Plate 4, Fig. 7, _b_. Injuries, when they are
+sufficiently severe to leave permanent scars, destroy the ridges to that
+extent. If a piece of flesh is sliced off, or if an ulcer has eaten so
+deeply as to obliterate the perspiratory glands, a white cicatrix, without
+pores or ridges, is the result (Fig. 7, _a_). Lesser injuries are not
+permanent. My assistant happened to burn his finger rather sharply; the
+daily prints he took of it, illustrated the progress of healing in an
+interesting manner; finally the ridges were wholly restored. A deep clean
+cut leaves a permanent thin mark across the ridges (Fig. 7, _c_),
+sometimes without any accompanying puckering; but there is often a
+displacement of the ridges on both sides of it, exactly like a "fault" in
+stratified rocks. A cut, or other injury that is not a clean incision,
+leaves a scar with puckerings on all sides, as in Fig. 7, _a_, making the
+ridges at that part undecipherable, even if it does not wholly obliterate
+them.
+
+The latest and best investigations on the evolution of the ridges have
+been made by Dr. H. Klaatsch.[2] He shows that the earliest appearance in
+the Mammalia of structures analogous to ridges is one in which small
+eminences occur on the ball of the foot, through which the sweat glands
+issue in no particular order. The arrangement of the papillae into rows,
+and the accompanying orderly arrangement of the sweat glands, is a
+subsequent stage in evolution. The prehensile tail of the Howling Monkey
+serves as a fifth hand, and the naked concave part of the tail, with which
+it grasps and holds on to boughs, is furnished with ridges arranged
+transversely in beautiful order. The numerous drawings of the hands of
+monkeys by Allix[3] may be referred to with advantage.
+
+The uses of the ridges are primarily, as I suppose, to raise the mouths of
+the ducts, so that the excretions which they pour out may the more easily
+be got rid of; and secondarily, in some obscure way, to assist the sense
+of touch. They are said to be moulded upon the subcutaneous papillae in
+such a manner that the ultimate organs of touch, namely, the Pacinian
+bodies, etc.--into the variety of which it is unnecessary here to
+enter--are more closely congregated under the bases of the ridges than
+under the furrows, and it is easy, on those grounds, to make reasonable
+guesses how the ridges may assist the sense of touch. They must
+concentrate pressures, that would otherwise be spread over the surface
+generally, upon the parts which are most richly supplied with the
+terminations of nerves. By their means it would become possible to
+neutralise the otherwise dulling effect of a thick protective epidermis.
+Their existence in transverse ridges on the inner surface of the
+prehensile tails of monkeys admits of easy justification from this point
+of view. The ridges so disposed cannot prevent the tail from curling, and
+they must add materially to its sensitiveness. They seem to produce the
+latter effect on the hands of man, for, as the epidermis thickens under
+use within moderate limits, so the prominence of the ridges increases.
+
+Supposing the ultimate organs of the sense of touch to be really
+congregated more thickly under the ridges than under the furrows--on which
+there has been some question--the power of tactile discrimination would
+depend very much on the closeness of the ridges. The well-known experiment
+with the two points of a pair of compasses, is exactly suited to test the
+truth of this. It consists in determining the smallest distance apart, of
+the two points, at which their simultaneous pressure conveys the sensation
+of a double prick. Those persons in whom the ridge-interval was short
+might be expected to perceive the double sensation, while others whose
+ridge-interval was wide would only perceive a single one, the distance
+apart of the compass points, and the parts touched by them, being the same
+in both cases. I was very glad to avail myself of the kind offer of Mr.
+E. B. Titchener to make an adequate course of experiments at Professor
+Wundt's psycho-physical laboratory at Leipzig, to decide this question. He
+had the advantage there of being able to operate on fellow-students who
+were themselves skilled in such lines of investigation, so while his own
+experience was a considerable safeguard against errors of method, that
+safety was reinforced by the fact that his experiments were conducted
+under the watchful eyes of competent and critical friends. The result of
+the enquiry was decisive. It was proved to demonstration that the fineness
+or coarseness of the ridges in different persons had no effect whatever on
+the delicacy of their tactile discrimination. Moreover, it made no
+difference in the results, whether one or both points of the compass
+rested on the ridges or in the furrows.
+
+The width of the ridge-interval is certainly no test of the relative power
+of discrimination of the different parts of the same hand, because, while
+the ridge-interval is nearly uniform over the whole of the palmar surface,
+the least distance between the compass points that gives the sensation of
+doubleness is more than four times greater when they are applied to some
+parts of the palm than when they are applied to the bulbs of the fingers.
+
+The ridges may subserve another purpose in the act of touch, namely, that
+of enabling the character of surfaces to be perceived by the act of
+rubbing them with the fingers. We all of us perform this, as it were,
+intuitively. It is interesting to ask a person who is ignorant of the
+real intention, to shut his eyes and to ascertain as well as he can by the
+sense of touch alone, the material of which any object is made that is
+afterwards put into his hands. He will be observed to explore it very
+carefully by rubbing its surface in many directions, and with many degrees
+of pressure. The ridges engage themselves with the roughness of the
+surface, and greatly help in calling forth the required sensation, which
+is that of a thrill; usually faint, but always to be perceived when the
+sensation is analysed, and which becomes very distinct when the
+indentations are at equal distances apart, as in a file or in velvet. A
+thrill is analogous to a musical note, and the characteristics to the
+sense of touch, of different surfaces when they are rubbed by the fingers,
+may be compared to different qualities of sound or noise. There are,
+however, no pure over-tones in the case of touch, as there are in nearly
+all sounds.
+
+
+
+
+CHAPTER V
+
+PATTERNS: THEIR OUTLINES AND CORES
+
+
+The patterns on the thumb and fingers were first discussed at length by
+Purkenje in 1823, in a University Thesis or _Commentatio_. I have
+translated the part that chiefly concerns us, and appended it to this
+chapter together with his corresponding illustrations. Subsequent writers
+have adopted his standard types, diminishing or adding to their number as
+the case may be, and guided as he had been, by the superficial appearance
+of the lineations.
+
+In my earlier trials some three years ago, an attempt at classification
+was made upon that same principle, when the experience gained was
+instructive. It had seemed best to limit them to the prints of a single
+digit, and the thumb was selected. I collected enough specimens to fill
+fourteen sheets, containing in the aggregate 504 prints of right thumbs,
+arranged in six lines and six columns (6 x 6 x 14 = 504), and another set
+of fourteen sheets containing the corresponding left thumbs. Then, for the
+greater convenience of study these sheets were photographed, and
+enlargements upon paper to about two and a half times the natural size
+made from the negatives. The enlargements of the right thumb prints were
+reversed, in order to make them comparable on equal terms with those of
+the left. The sheets were then cut up into rectangles about the size of
+small playing-cards, each of which contained a single print, and the
+register number in my catalogue was entered on its back, together with the
+letters L. for left, or R.R. for reversed right, as the case might be.
+
+On trying to sort them according to Purkenje's standards, I failed
+completely, and many analogous plans were attempted without success. Next
+I endeavoured to sort the patterns into groups so that the central pattern
+of each group should differ by a unit of "equally discernible difference"
+from the central patterns of the adjacent groups, proposing to adopt those
+central patterns as standards of reference. After tedious re-sortings,
+some sixty standards were provisionally selected, and the whole laid by
+for a few days. On returning to the work with a fresh mind, it was painful
+to find how greatly my judgment had changed in the interim, and how faulty
+a classification that seemed tolerably good a week before, looked then.
+Moreover, I suffered the shame and humiliation of discovering that the
+identity of certain duplicates had been overlooked, and that one print had
+been mistaken for another. Repeated trials of the same kind made it
+certain that finality would never be reached by the path hitherto
+pursued.
+
+On considering the causes of these doubts and blunders, different
+influences were found to produce them, any one of which was sufficient by
+itself to give rise to serious uncertainty. A complex pattern is capable
+of suggesting various readings, as the figuring on a wall-paper may
+suggest a variety of forms and faces to those who have such fancies. The
+number of illusive renderings of prints taken from the same finger, is
+greatly increased by such trifles as the relative breadths of their
+respective lineations and the differences in their depths of tint. The
+ridges themselves are soft in substance, and of various heights, so that a
+small difference in the pressure applied, or in the quantity of ink used,
+may considerably affect the width of the lines and the darkness of
+portions of the print. Certain ridges may thereby catch the attention at
+one time, though not at others, and give a bias to some false conception
+of the pattern. Again, it seldom happens that different impressions of the
+same digit are printed from exactly the same part of it, consequently the
+portion of the pattern that supplies the dominant character will often be
+quite different in the two prints. Hence the eye is apt to be deceived
+when it is guided merely by the general appearance. A third cause of error
+is still more serious; it is that patterns, especially those of a spiral
+form, may be apparently similar, yet fundamentally unlike, the unaided eye
+being frequently unable to analyse them and to discern real differences.
+Besides all this, the judgment is distracted by the mere size of the
+pattern, which catches the attention at once, and by other secondary
+matters such as the number of turns in the whorled patterns, and the
+relative dimensions of their different parts. The first need to be
+satisfied, before it could become possible to base the classification upon
+a more sure foundation than that of general appearance, was to establish a
+well-defined point or points of reference in the patterns. This was done
+by utilising the centres of the one or two triangular plots (see Plate 4,
+Fig. 8, ~2~, ~3~, ~4~) which are found in the great majority of patterns,
+and whose existence was pointed out by Purkenje, but not their more remote
+cause, which is as follows:
+
+The ridges, as was shown in the diagram (Plate 3) of the palm of the hand,
+run athwart the fingers in rudely parallel lines up to the last joint, and
+if it were not for the finger-nail, would apparently continue parallel up
+to the extreme finger-tip. But the presence of the nail disturbs their
+parallelism and squeezes them downwards on both sides of the finger. (See
+Fig. 8, ~2~.) Consequently, the ridges that run close to the tip are
+greatly arched, those that successively follow are gradually less arched
+until, in some cases, all signs of the arch disappear at about the level
+of the first joint (Fig. 8, ~1~). Usually, however, this gradual
+transition from an arch to a straight line fails to be carried out,
+causing a break in the orderly sequence, and a consequent interspace (Fig.
+8, ~2~). The topmost boundary of the interspace is formed by the lowermost
+arch, and its lowermost boundary by the topmost straight ridge. But an
+equally large number of ducts exist within the interspace, as are to be
+found in adjacent areas of equal size, whose mouths require to be
+supported and connected. This is effected by the interpolation of an
+independent system of ridges arranged in loops (Fig. 8, ~3~; also Plate 5,
+Fig. 9, _a_, _f_), or in scrolls (Fig. 8, ~4~; also Fig. 9, _g_, _h_), and
+this interpolated system forms the "pattern." Now the existence of an
+interspace implies the divergence of two previously adjacent ridges (Fig.
+8, ~2~), in order to embrace it. Just in front of the place where the
+divergence begins, and before the sweep of the pattern is reached, there
+are usually one or more very short cross-ridges. Their effect is to
+complete the enclosure of the minute triangular plot in question. Where
+there is a plot on both sides of the finger, the line that connects them
+(Fig. 8, ~4~) serves as a base line whereby the pattern may be oriented,
+and the position of any point roughly charted. Where there is a plot on
+only one side of the finger (Fig. 8, ~3~), the pattern has almost
+necessarily an axis, which serves for orientation, and the pattern can
+still be charted, though on a different principle, by dropping a
+perpendicular from the plot on to the axis, in the way there shown.
+
+These plots form corner-stones to my system of outlining and subsequent
+classification; it is therefore extremely important that a sufficient area
+of the finger should be printed to include them. This can always be done
+by slightly _rolling_ the finger (p. 39), the result being, in the
+language of map-makers, a cylindrical projection of the finger (see Plate
+5, Fig. 9, _a-h_). Large as these impressions look, they are of the
+natural size, taken from ordinary thumbs.
+
+
+[Illustration: PLATE 5.
+
+FIG. 9. EXAMPLES OF OUTLINED PATTERNS (The Specimens are rolled
+impressions of natural size).]
+
+
+_The outlines._--The next step is to give a clear and definite shape to
+the pattern by drawing its outline (Fig. 9). Take a fine pen, pencil, or
+paint brush, and follow in succession each of the two diverging ridges
+that start from either plot. The course of each ridge must be followed
+with scrupulous conscientiousness, marking it with a clean line as far as
+it can be traced. If the ridge bifurcates, always follow the branch that
+trends towards the middle of the pattern. If it stops short, let the
+outline stop short also, and recommence on a fresh ridge, choosing that
+which to the best of the judgment prolongs the course of the one that
+stopped. These outlines have an extraordinary effect in making finger
+markings intelligible to an untrained eye. What seemed before to be a
+vague and bewildering maze of lineations over which the glance wandered
+distractedly, seeking in vain for a point on which to fix itself, now
+suddenly assumes the shape of a sharply-defined figure. Whatever
+difficulties may arise in classifying these figures, they are as nothing
+compared to those experienced in attempting to classify unoutlined
+patterns, the outlines giving a precision to their general features which
+was wanting before.
+
+After a pattern has been treated in this way, there is no further occasion
+to pore minutely into the finger print, in order to classify it correctly,
+for the bold firm curves of the outline are even more distinct than the
+largest capital letters in the title-page of a book.
+
+A fair idea of the way in which the patterns are distributed, is given by
+Plate 6. Eight persons were taken in the order in which they happened to
+present themselves, and Plate 6 shows the result. For greater clearness,
+colour has been employed to distinguish between the ridges that are
+supplied from the inner and outer sides of the hand respectively. The
+words right and left _must be avoided_ in speaking of patterns, for the
+two hands are symmetrically disposed, only in a reversed sense. The right
+hand does not look like a left hand, but like the reflection of a left
+hand in a looking-glass, and _vice versa_. The phrases we shall employ
+will be the _Inner_ and the _Outer_; or thumb-side and little-finger side
+(terms which were unfortunately misplaced in my memoir in the _Phil.
+Trans._ 1891).
+
+There need be no difficulty in remembering the meaning of these terms, if
+we bear in mind that the great toes are undoubtedly innermost; that if we
+walked on all fours as children do, and as our remote ancestors probably
+did, the thumbs also would be innermost, as is the case when the two hands
+are impressed side by side on paper. Inner and outer are better than
+thumb-side and little-finger side, because the latter cannot be applied to
+the thumbs and little fingers themselves. The anatomical words radial and
+ulnar referring to the two bones of the fore-arm, are not in popular use,
+and they might be similarly inappropriate, for it would sound oddly to
+speak of the radial side of the radius.
+
+
+[Illustration: PLATE 6.
+
+FIG. 10. OUTLINES OF THE PATTERNS OF THE DIGITS OF EIGHT PERSONS, TAKEN AT
+RANDOM.]
+
+
+The two plots just described will therefore be henceforth designated as
+the Inner and the Outer plots respectively, and symbolised by the letters
+I and O.
+
+The system of ridges in Fig. 10 that comes from the inner side "I" are
+coloured blue; those from the outer "O" are coloured red. The employment
+of colour instead of variously stippled surfaces is of conspicuous
+advantage to the great majority of persons, though unhappily nearly
+useless to about one man in every twenty-five, who is constitutionally
+colour-blind.
+
+It may be convenient when marking finger prints with letters for
+reference, to use those that look alike, both in a direct and in a
+reversed aspect, as they may require to be read either way. The print is a
+reversed picture of the pattern upon the digit that made it. The pattern
+on one hand is, as already said, a reversed picture of a similar pattern
+as it shows on the other. In the various processes by which prints are
+multiplied, the patterns may be reversed and re-reversed. Thus, if a
+finger is impressed on a lithographic stone, the impressions from that
+stone are reversals of the impression made by the same finger upon paper.
+If made on transfer paper and thence transferred to stone, there is a
+re-reversal. There are even more varied possibilities when photography is
+employed. It is worth recollecting that there are twelve capital letters
+in the English alphabet which, if printed in block type, are unaffected by
+being reversed. They are A.H.I.M.O.T.U.V.W.X.Y.Z. Some symbols do the
+same, such as, * + - = :. These and the letters H.O.I.X. have the
+further peculiarity of appearing unaltered when upside down.
+
+_Lenses._--As a rule, only a small magnifying power is needed for drawing
+outlines, sufficient to allow the eye to be brought within six inches of
+the paper, for it is only at that short distance that the _minutiae_ of a
+full-sized finger print begin to be clearly discerned. Persons with normal
+sight, during their childhood and boy- or girlhood, are able to read as
+closely as this without using a lens, the range in adjustment of the focus
+of the eye being then large. But as age advances the range contracts, and
+an elderly person with otherwise normal eyesight requires glasses to read
+a book even at twelve inches from his eye. I now require much optical aid;
+when reading a book, spectacles of 12-inch focus are necessary; and when
+studying a finger print, 12-inch eye-glasses in addition, the double power
+enabling me to see clearly at a distance of only six inches. Perhaps the
+most convenient focus for a lens in ordinary use is 3 inches. It should be
+mounted at the end of a long arm that can easily be pushed in any
+direction, sideways, backwards, forwards, and up or down. It is
+undesirable to use a higher power than this unless it is necessary,
+because the field of view becomes narrowed to an inconvenient degree, and
+the nearer the head is to the paper, the darker is the shadow that it
+casts; there is also insufficient room for the use of a pencil.
+
+Every now and then a closer inspection is wanted; for which purpose a
+doublet of 1/2-inch focus, standing on three slim legs, answers well.
+
+For studying the markings on the fingers themselves, a small folding lens,
+sold at opticians' shops under the name of a "linen tester," is very
+convenient. It is so called because it was originally constructed for the
+purpose of counting the number of threads in a given space, in a sample of
+linen. It is equally well adapted for counting the number of ridges in a
+given space.
+
+ * * * * *
+
+Whoever desires to occupy himself with finger prints, ought to give much
+time and practice to drawing outlines of different impressions of the same
+digits. His own ten fingers, and those of a few friends, will furnish the
+necessary variety of material on which to work. He should not rest
+satisfied until he has gained an assurance that all patterns possess
+definite figures, which may be latent but are potentially present, and
+that the ridges form something more than a nondescript congeries of
+ramifications and twists. He should continue to practise until he finds
+that the same ridges have been so nearly followed in duplicate
+impressions, that even in difficult cases his work will rarely vary more
+than a single ridge-interval.
+
+When the triangular plot happens not to be visible, owing to the print
+failing to include it, which is often the case when the finger is not
+rolled, as is well shown in the prints of my own ten digits on the
+title-page, the trend of the ridges so far as they are seen, usually
+enables a practised eye to roughly estimate its true position. By means of
+this guidance an approximate, but fairly correct, outline can be drawn.
+When the habit of judging patterns by their outlines has become familiar,
+the eye will trace them for itself without caring to draw them, and will
+prefer an unoutlined pattern to work upon, but even then it is essential
+now and then to follow the outline with a fine point, say that of a
+penknife or a dry pen.
+
+In selecting standard forms of patterns for the convenience of
+description, we must be content to disregard a great many of the more
+obvious characteristics. For instance, the size of generally similar
+patterns in Fig. 10 will be found to vary greatly, but the words large,
+medium, or small may be applied to any pattern, so there is no necessity
+to draw a standard outline for each size. Similarly as regards the inwards
+or outwards slope of patterns, it is needless to print here a separate
+standard outline for either slope, and equally unnecessary to print
+outlines in duplicate, with reversed titles, for the right and left hands
+respectively. The phrase "a simple spiral" conveys a well-defined general
+idea, but there are four concrete forms of it (see bottom row of Plate 11,
+Fig. 17, _oj_, _jo_, _ij_, _ji_) which admit of being verbally
+distinguished. Again the internal proportions of any pattern, say those of
+simple spirals, may vary greatly without affecting the fact of their being
+simple spirals. They may be wide or narrow at their mouths, they may be
+twisted up into a point (Plate 8, Fig. 14, ~52~), or they may run in broad
+curls of uniform width (Fig. 14, ~51~, ~54~). Perhaps the best general
+rule in selecting standard outlines, is to limit them to such as cannot be
+turned into any other by viewing them in an altered aspect, as upside down
+or from the back, or by magnifying or deforming them, whether it be
+through stretching, shrinking, or puckering any part of them. Subject to
+this general rule and to further and more particular descriptions, the
+sets (Plates 7 and 8, Figs. 11, 12, 13) will be found to give considerable
+help in naming the usual patterns.
+
+
+[Illustration: PLATE 7.
+
+FIG. 11. ARCHES.
+
+FIG. 12. LOOPS.]
+
+
+[Illustration: PLATE 8.
+
+FIG. 13. WHORLS. CORES TO LOOPS.
+
+FIG. 14. Rods:--their envelopes are indicated by dots. Staples:--their
+envelopes are indicated by dots. Envelopes whether to Rods or
+Staples:--here staples only are dotted.
+
+FIG. 15. CORES TO WHORLS.]
+
+
+It will be observed that they are grouped under the three principal heads
+of Arches, Loops, and Whorls, and that under each of these heads some
+analogous patterns as ~4~, ~5~, ~7~, ~8~, etc., are introduced and
+underlined with the word "see" so and so, and thus noted as really
+belonging to one of the other heads. This is done to indicate the
+character of the transitional cases that unite respectively the Arches
+with the Loops, the Arches with the Whorls, and the Loops with the Whorls.
+More will follow in respect to these. The "tented arch" (~3~) is extremely
+rare on the thumb; I do not remember ever to have seen it there,
+consequently it did not appear in the plate of patterns in the _Phil.
+Trans._ which referred to thumbs. On the other hand, the "banded duplex
+spiral" (~30~) is common in the thumb, but rare elsewhere. There are some
+compound patterns, especially the "spiral in loop" (~21~) and the "circlet
+in loop" (~22~), which are as much loops as whorls; but are reckoned as
+whorls. The "twinned loop" (~16~) is of more frequent occurrence than
+would be supposed from the examination of _dabbed_ impressions, as the
+only part of the outer loop then in view resembles outside arches; it is
+due to a double separation of the ridges (Plate 4, Fig. 8), and a
+consequent double interspace. The "crested loop" (~13~) may sometimes be
+regarded as an incipient form of a "duplex spiral" (~29~).
+
+The reader may also refer to Plate 16, which contains what is there called
+the C set of standard patterns. They were arranged and used for a special
+purpose, as described in Chapter XI. They refer to impressions of the
+right hand.
+
+As a variety of Cores, differing in shape and size, may be found within
+each of the outlines, it is advisable to describe them separately. Plate
+8, Fig. 14 shows a series of the cores of loops, in which the innermost
+lineations may be either straight or curved back; in the one case they are
+here called rods (~31~ to ~35~); in the other (~36~ to ~42~), staples. The
+first of the ridges that envelops the core, whether the core be a rod,
+many rods, or a staple, is also shown and named (~43~ to ~48~). None of
+the descriptions are intended to apply to more than the _very end_ of the
+core, say, from the tip downwards to a distance equal to two average
+ridge-intervals in length. If more of the core be taken into account, the
+many varieties in their lower parts begin to make description confusing.
+In respect to the "parted" staples and envelopes, and those that are
+single-eyed, the description may further mention the side on which the
+parting or the eye occurs, whether it be the Inner or the Outer.
+
+At the bottom of Fig. 14, ~49-54~, is given a series of rings, spirals,
+and plaits, in which nearly all the clearly distinguishable varieties are
+included, no regard being paid to the direction of the twist or to the
+number of turns. ~49~ is a set of concentric circles, ~50~ of ellipses:
+they are rarely so in a strict sense throughout the pattern, usually
+breaking away into a more or less spiriform arrangement as in ~51~. A
+curious optical effect is connected with the circular forms, which becomes
+almost annoying when many specimens are examined in succession. They seem
+to be cones standing bodily out from the paper. This singular appearance
+becomes still more marked when they are viewed with only one eye; no
+stereoscopic guidance then correcting the illusion of their being contour
+lines.
+
+Another curious effect is seen in ~53~, which has the appearance of a
+plait or overlap; two systems of ridges that roll together, end bluntly,
+the end of the one system running right into a hollow curve of the other,
+and there stopping short; it seems, at the first glance, to run beneath
+it, as if it were a plait. This mode of ending forms a singular contrast
+to that shown in ~51~ and ~52~, where the ridges twist themselves into a
+point. ~54~ is a deep spiral, sometimes having a large core filled with
+upright and nearly parallel lines; occasionally they are bulbous, and
+resemble the commoner "monkey" type, see ~35~.
+
+When the direction of twist is described, the language must be
+unambiguous: the following are the rules I adopt. The course of the ridge
+is always followed _towards_ the _centre_ of the pattern, and not away
+from it. Again, the direction of its course when so followed is specified
+at the place where it attains its _highest_ point, or that nearest to the
+finger-tip; its course at that point must needs be horizontal, and
+therefore directed either towards the inner or the outer side.
+
+The amount of twist has a strong tendency to coincide with either one,
+two, three, four, or more half-turns, and not to stop short in
+intermediate positions. Here are indications of some unknown fundamental
+law, analogous apparently to that which causes Loops to be by far the
+commonest pattern.
+
+ * * * * *
+
+The classification into Arches, Loops, and Whorls is based on the degree
+of curvature of the ridges, and enables almost any pattern to be sorted
+under one or other of those three heads. There are a few ambiguous
+patterns, and others which are nondescript, but the former are uncommon
+and the latter rare; as these exceptions give little real inconvenience,
+the classification works easily and well.
+
+Arches are formed when the ridges run from one side to the other of the
+bulb of the digit without making any backward turn or twist. Loops, when
+there is a single backward turn, but no twist. Whorls, when there is a
+turn through at least one complete circle; they are also considered to
+include all duplex spirals.
+
+
+[Illustration: PLATE 9.
+
+FIG. 15. TRANSITIONAL PATTERNS--ARCHES AND LOOPS (enlarged three times).]
+
+
+[Illustration: PLATE 10.
+
+FIG. 16. TRANSITIONAL PATTERNS--LOOPS AND WHORLS (enlarged three times).]
+
+
+The chief theoretical objection to this threefold system of classification
+lies in the existence of certain compound patterns, by far the most common
+of which are Whorls enclosed within Loops (Plates 7, 8, Fig. 12, ~15~,
+~18~, ~19~, and Fig. 13, ~20-23~). They are as much Loops as Whorls, and
+properly ought to be relegated to a fourth class. I have not done so, but
+called them Whorls, for a practical reason which is cogent. In an
+imperfect impression, such as is made by merely dabbing the inked finger
+upon paper, the enveloping loop is often too incompletely printed to
+enable its existence to be surely ascertained, especially when the
+enclosed whorl is so large (Fig. 13, ~23~) that there are only one or two
+enveloping ridges to represent the loop. On the other hand, the whorled
+character of the core can hardly fail to be recognised. The practical
+difficulties lie almost wholly in rightly classifying a few transitional
+forms, diagrammatically and roughly expressed in Fig. 11, ~4~, ~5~, and
+Fig. 12, ~8~, ~18~, ~19~, with the words "see" so and so written below,
+and of which actual examples are given on an enlarged scale in Plates 9
+and 10, Figs. 15 and 16. Here Fig. 15, _a_ is an undoubted arch, and _c_
+an undoubted nascent loop; but _b_ is transitional between them, though
+nearer to a loop than an arch, _d_ may be thought transitional in the same
+way, but it has an incipient curl which becomes marked in _e_, while it
+has grown into a decided whorl in _f_; _d_ should also be compared with
+_j_, which is in some sense a stage towards _k_. _g_ is a nascent
+tented-arch, fully developed in _i_, where the pattern as a whole has a
+slight slope, but is otherwise fairly symmetrical. In _h_ there is some
+want of symmetry, and a tendency to the formation of a loop on the right
+side (refer back to Plate 7, Fig. 11, ~4~, and Fig. 12, ~12~); it is a
+transitional case between a tented arch and a loop, with most resemblance
+to the latter. Plate 10, Fig. 16 illustrates eyed patterns; here _l_ and
+_m_ are parts of decided loops; _p_, _q_, and _r_ are decided whorls, but
+_n_ is transitional, inclining towards a loop, and _o_ is transitional,
+inclining towards a whorl. _s_ is a nascent form of an invaded loop, and
+is nearly related to _l_; _t_ and _u_ are decidedly invaded loops.
+
+The Arch-Loop-Whorl, or, more briefly, the A. L. W. system of
+classification, while in some degree artificial, is very serviceable for
+preliminary statistics, such as are needed to obtain a broad view of the
+distribution of the various patterns. A minute subdivision under numerous
+heads would necessitate a proportional and somewhat overwhelming amount of
+statistical labour. Fifty-four different standard varieties are by no
+means an extravagant number, but to treat fifty-four as thoroughly as
+three would require eighteen times as much material and labour. Effort is
+economised by obtaining broad results from a discussion of the A. L. W.
+classes, afterwards verifying or extending them by special inquiries into
+a few of the further subdivisions.
+
+
+[Illustration: PLATE 11.
+
+FIG. 17. ORIGIN OF SUPPLY OF RIDGES TO PATTERNS OF PRINTS OF RIGHT HAND.
+
+FIG. 18. Ambiguities in prints of the Minutiae.]
+
+
+The divergent ridges that bound any simple pattern admit of nine, and only
+nine, distinct variations in the first part of their course. The bounding
+ridge that has attained the summit of any such pattern must have arrived
+either from the Inner plot (I), the Outer plot (O), or from both.
+Similarly as regards the bounding ridge that lies at the lowest point of
+the pattern. Any one of the three former events may occur in connection
+with any of the three latter events, so they afford in all 3 x 3, or nine
+possible combinations. It is convenient to distinguish them by easily
+intelligible symbols. Thus, let _i_ signify a bounding line which starts
+from the point I, whether it proceeds to the summit or to the base of the
+pattern; let _o_ be a line that similarly proceeds from O, and let _u_ be
+a line that unites the two plots I and O, either by summit or by base.
+Again, let two symbols be used, of which the first shall always refer to
+the summit, and the second to the base of the pattern. Then the nine
+possible cases are--_uu_, _ui_, _uo_; _iu_, _ii_, _io_; _ou_, _oi_, _oo_.
+The case of the arches is peculiar, but they may be fairly classed under
+the symbol _uu_.
+
+This easy method of classification has much power. For example, the four
+possible kinds of simple spirals (see the 1st, 2nd, and the 5th and 6th
+diagrams in the lowest row of Plate 11, Fig. 17) are wholly determined by
+the letters _oj_, _jo_, _ij_, _ji_ respectively. The two forms of duplex
+spirals are similarly determined by _oi_ and _io_ (see 4th and 5th
+diagrams in the upper row of Fig. 17), the two slopes of loops by _oo_ and
+_ii_ (3rd and 4th in the lower row). It also shows very distinctly the
+sources whence the streams of ridges proceed that feed the pattern, which
+itself affords another basis for classification. The resource against
+uncertainty in respect to ambiguous or difficult patterns is to compile a
+dictionary of them, with the heads under which it is advisable that they
+should severally be classed. It would load these pages too heavily to give
+such a dictionary here. Moreover, it ought to be revised by many
+experienced eyes, and the time is hardly ripe for this; when it is, it
+would be no difficult task, out of the large number of prints of separate
+fingers which for instance I possess (some 15,000), to make an adequate
+selection, to enlarge them photographically, and finally to print the
+results in pairs, the one untouched, the other outlined and classified.
+
+It may be asked why ridges are followed and not furrows, the furrow being
+the real boundary between two systems. The reply is, that the ridges are
+the easiest to trace; and, as the error through following the ridges
+cannot exceed one-half of a ridge-interval, I have been content to
+disregard it. I began by tracing furrows, but preferred the ridges after
+trial.
+
+_Measurements._--It has been already shown that when both plots are
+present (Plate 4, Fig. 8, ~4~), they form the termini of a base line, from
+which any part of the pattern may be triangulated, as surveyors would say.
+Also, that when only one plot exists (~3~), and the pattern has an axis
+(which it necessarily has in all ordinary _ii_ and _oo_ cases), a
+perpendicular can be let fall upon that axis, whose intersection with it
+will serve as a second point of reference. But our methods must not be too
+refined. The centres of the plots are not determinable with real
+exactness, and repeated prints from so soft a substance as flesh are
+often somewhat dissimilar, the one being more or less broadened out than
+the other, owing to unequal pressure. It is therefore well to use such
+other more convenient points of reference as the particular pattern may
+present. In loops, the intersection of the axis with the summit of the
+innermost bend, whether it be a staple or the envelope to a rod (Fig. 14,
+second and third rows of diagrams), is a well-defined position. In
+spirals, the centre of the pattern is fairly well defined; also a
+perpendicular erected from the middle of the base to the outline above and
+below (Fig. 8, ~4~) is precise and convenient.
+
+In prints of adults, measurements may be made in absolute units of length,
+as in fractions of an inch, or else in millimetres. An average
+ridge-interval makes, however, a better unit, being independent of growth;
+it is strictly necessary to adopt it in prints made by children, if
+present measurements are hereafter to be compared with future ones. The
+simplest plan of determining and employing this unit is to count the
+number of ridges to the nearest half-ridge, within the space of one-tenth
+of an inch, measured along the axis of the finger at and about the point
+where it cuts the _summit_ of the outline; then, having already prepared
+scales suitable for the various likely numbers, to make the measurements
+with the appropriate scale. Thus, if five ridges were crossed by the axis
+at that part, in the space of one-tenth of an inch, each unit of the scale
+to be used would be one-fiftieth of an inch; if there were four ridges,
+each unit of the scale would be one-fortieth of an inch; if six ridges
+one-sixtieth, and so forth. There is no theoretical or practical
+difficulty, only rough indications being required.
+
+It is unnecessary to describe in detail how the bearings of any point may
+be expressed after the fashion of compass bearings, the direction I-O
+taking the place of East-West, the uppermost direction that of North, and
+the lowermost of South. Little more is practically wanted than to be able
+to describe roughly the position of some remarkable feature in the print,
+as of an island or an enclosure. A ridge that is characterised by these or
+any other marked peculiarity is easily identified by the above means, and
+it thereupon serves as an exact basis for the description of other
+features.
+
+
+_Purkenje's "Commentatio."_
+
+Reference has already been made to Purkenje, who has the honour of being
+the person who first described the inner scrolls (as distinguished from
+the outlines of the patterns) formed by the ridges. He did so in a
+University Thesis delivered at Breslau in 1823, entitled _Commentatio de
+examine physiologico organi visus et systematis cutanei_ (a physiological
+examination of the visual organ and of the cutaneous system). The thesis
+is an ill-printed small 8vo pamphlet of fifty-eight pages, written in a
+form of Latin that is difficult to translate accurately into free English.
+It is, however, of great historical interest and reputation, having been
+referred to by nearly all subsequent writers, some of whom there is
+reason to suspect never saw it, but contented themselves with quoting a
+very small portion at second-hand. No copy of the pamphlet existed in any
+public medical library in England, nor in any private one so far as I
+could learn; neither could I get a sight of it at some important
+continental libraries. One copy was known of it in America. The very
+zealous Librarian of the Royal College of Surgeons was so good as to take
+much pains at my instance, to procure one: his zeal was happily and
+unexpectedly rewarded by success, and the copy is now securely lodged in
+the library of the College.
+
+_The Title_
+
+Commentatio de Examine physiologico organi visus et systematis cutanei
+quam pro loco in gratioso medicorum ordine rite obtinendo die Dec. 22,
+1823. H.X.L.C. publice defendit Johannes Evangelista Purkenje, Med.
+doctor, Phys. et Path. Professor publicus ordinarius des. Assumto socio
+Guilielmo Kraus Medicinae studioso.
+
+_Translation_, p. 42.
+
+ "Our attention is next engaged by the wonderful arrangement and
+ curving of the minute furrows connected with the organ of touch[4] on
+ the inner surfaces of the hand and foot, especially on the last
+ phalanx of each finger. Some general account of them is always to be
+ found in every manual of physiology and anatomy, but in an organ of
+ such importance as the human hand, used as it is for very varied
+ movements, and especially serviceable to the sense of touch, no
+ research, however minute, can fail in yielding some gratifying
+ addition to our knowledge of that organ. After numberless
+ observations, I have thus far met with nine principal varieties of
+ curvature according to which the tactile furrows are disposed upon the
+ inner surface of the last phalanx of the fingers. I will describe them
+ concisely, and refer to the diagrams for further explanation (see
+ Plate 12, Fig. 19).
+
+ 1. _Transverse flexures._--The minute furrows starting from the bend
+ of the joint, run from one side of the phalanx to the other; at first
+ transversely in nearly straight lines, then by degrees they become
+ more and more curved towards the middle, until at last they are bent
+ into arches that are almost concentric with the circumference of the
+ finger.
+
+ 2. _Central Longitudinal Stria._--This configuration is nearly the
+ same as in 1, the only difference being that a perpendicular stria is
+ enclosed within the transverse furrows, as if it were a nucleus.
+
+ 3. _Oblique Stria._--A solitary line runs from one or other of the two
+ sides of the finger, passing obliquely between the transverse curves
+ in 1, and ending near the middle.
+
+ 4. _Oblique Sinus._--If this oblique line recurves towards the side
+ from which it started, and is accompanied by several others, all
+ recurved in the same way, the result is an oblique sinus, more or less
+ upright, or horizontal, as the case may be. A junction at its base, of
+ minute lines proceeding from either of its sides, forms a triangle.
+ This distribution of the furrows, in which an oblique sinus is found,
+ is by far the most common, and it may be considered as a special
+ characteristic of man; the furrows that are packed in longitudinal
+ rows are, on the other hand, peculiar to monkeys. The vertex of the
+ oblique sinus is generally inclined towards the radial side of the
+ hand, but it must be observed that the contrary is more frequently the
+ case in the fore-finger, the vertex there tending towards the ulnar
+ side. Scarcely any other configuration is to be found on the toes. The
+ ring finger, too, is often marked with one of the more intricate kinds
+ of pattern, while the remaining fingers have either the oblique sinus
+ or one of the other simpler forms.
+
+
+[Illustration: PLATE 12.
+
+FIG. 19. THE STANDARD PATTERNS OF PURKENJE.]
+
+
+ 5. _Almond._--Here the oblique sinus, as already described, encloses
+ an almond-shaped figure, blunt above, pointed below, and formed of
+ concentric furrows.
+
+ 6. _Spiral._--When the transverse flexures described in 1 do not pass
+ gradually from straight lines into curves, but assume that form
+ suddenly with a more rapid divergence, a semicircular space is
+ necessarily created, which stands upon the straight and horizontal
+ lines below, as it were upon a base. This space is filled by a spiral
+ either of a simple or composite form. The term 'simple' spiral is to
+ be understood in the usual geometric sense. I call the spiral
+ 'composite' when it is made up of several lines proceeding from the
+ same centre, or of lines branching at intervals and twisted upon
+ themselves. At either side, where the spiral is contiguous to the
+ place at which the straight and curved lines begin to diverge, in
+ order to enclose it, two triangles are formed, just like the single
+ one that is formed at the side of the oblique sinus.
+
+ 7. _Ellipse_, or _Elliptical Whorl_.--The semicircular space described
+ in 6 is here filled with concentric ellipses enclosing a short single
+ line in their middle.
+
+ 8. _Circle_, or _Circular Whorl_.--Here a single point takes the place
+ of the short line mentioned in 7. It is surrounded by a number of
+ concentric circles reaching to the ridges that bound the semicircular
+ space.
+
+ 9. _Double Whorl._--One portion of the transverse lines runs forward
+ with a bend and recurves upon itself with a half turn, and is embraced
+ by another portion which proceeds from the other side in the same way.
+ This produces a doubly twisted figure which is rarely met with except
+ on the thumb, fore, and ring fingers. The ends of the curved portions
+ may be variously inclined; they may be nearly perpendicular, of
+ various degrees of obliquity, or nearly horizontal.
+
+ In all of the forms 6, 7, 8, and 9, triangles may be seen at the
+ points where the divergence begins between the transverse and the
+ arched lines, and at both sides. On the remaining phalanges, the
+ transverse lines proceed diagonally, and are straight or only slightly
+ curved."
+
+(He then proceeds to speak of the palm of the hand in men and in
+monkeys.)
+
+
+
+
+CHAPTER VI
+
+PERSISTENCE
+
+
+The evidence that the minutiae persist throughout life is derived from the
+scrutiny and comparison of various duplicate impressions, one of each pair
+having been made many years ago, the other recently. Those which I have
+studied more or less exhaustively are derived from the digits of fifteen
+different persons. In some cases repeated impressions of one finger only
+were available; in most cases of two fingers; in some of an entire hand.
+Altogether the whole or part of repeated impressions of between twenty and
+thirty different digits have been studied. I am indebted to Sir W. J.
+Herschel for almost all these valuable data, without which it would have
+been impossible to carry on the inquiry. The only other prints are those
+of Sir W. G----, who, from curiosity, took impressions of his own fingers
+in sealing-wax in 1874, and fortunately happened to preserve them. He was
+good enough to make others for me last year, from which photographic
+prints were made. The following table gives an analysis of the above data.
+It would be well worth while to hunt up and take the present finger
+prints of such of the Hindoos as may now be alive, whose impressions were
+taken in India by Sir W. J. Herschel, and are still preserved. Many years
+must elapse before my own large collection of finger prints will be
+available for the purpose of testing persistence during long periods.
+
+The pattern in every distinct finger print, even though it be only a
+dabbed impression, contains on a rough average thirty-five different
+points of reference, in addition to its general peculiarities of outline
+and core. They consist of forkings, beginnings or ends of ridges, islands,
+and enclosures. These minute details are by no means peculiar to the
+pattern itself, but are distributed with almost equal abundance throughout
+the whole palmar surface. In order to make an exhaustive comparison of two
+impressions they ought to be photographically enlarged to a size not
+smaller than those shown in Plate 15. Two negatives of impressions can
+thus be taken side by side on an ordinary quarter-plate, and any number of
+photographic prints made from them; but, for still more comfortable
+working, a further enlargement is desirable, say by the prism, p. 52. Some
+of the prints may be made on ferro-prussiate paper, as already mentioned
+pp. 51, 53; they are more convenient by far than prints made by the silver
+or by the platinum process.
+
+Having placed the enlarged prints side by side, two or three conspicuous
+and convenient points of reference, whether islands, enclosures, or
+particularly distinct bifurcations, should be identified and marked. By
+their help, the position of the prints should be readjusted, so that they
+shall be oriented exactly alike. From each point of reference, in
+succession, the spines of the ridges are then to be followed with a fine
+pencil, in the two prints alternately, neatly marking each new point of
+comparison with a numeral in coloured ink (Plate 13). When both of the
+prints are good and clear, this is rapidly done; wherever the impressions
+are faulty, there may be many ambiguities requiring patience to unravel.
+At first I was timid, and proceeded too hesitatingly when one of the
+impressions was indistinct, making short alternate traces. Afterwards on
+gaining confidence, I traced boldly, starting from any well-defined point
+of reference and not stopping until there were reasonable grounds for
+hesitation, and found it easy in this way to trace the unions between
+opposite and incompletely printed ends of ridges, and to disentangle many
+bad impressions.
+
+An exact correspondence between the _details_ of two minutiae is of
+secondary importance. Thus, the commonest point of reference is a
+bifurcation; now the neck or point of divergence of a new ridge is apt to
+be a little low, and sometimes fails to take the ink; hence a new ridge
+may appear in one of the prints to have an independent origin, and in the
+other to be a branch. The _apparent_ origin is therefore of little
+importance, the main fact to be attended to is that a new ridge comes into
+existence at a particular point; _how_ it came into existence is a
+secondary matter. Similarly, an apparently broken ridge may in reality be
+due to an imperfectly printed enclosure; and an island in one print may
+appear as part of an enclosure in the other. Moreover, this variation in
+details may be the effect not only of imperfect inking or printing, but of
+disintegration due to old age, which renders the impressions of the ridges
+ragged and broken, as in my own finger prints on the title-page.
+
+Plate 11, Fig. 18 explains the nature of the apparent discrepancies better
+than a verbal description. In _a_ a new ridge appears to be suddenly
+intruded between two adjacent ones, which have separated to make room for
+it; but a second print, taken from the same finger, may have the
+appearance of either _b_ or _c_, showing that the new ridge is in reality
+a fork of one or other of them, the low connecting neck having failed to
+leave an impression. The second line of examples shows how an enclosure
+which is clearly defined in _d_ may give rise to the appearance of broken
+continuity shown in _e_, and how a distinct island _f_ in one of the
+prints may be the remnant of an enclosure which is shown in the other.
+These remarks are offered as a caution against attaching undue importance
+to disaccord in the details of the minutiae that are found in the same
+place in different prints. Usually, however, the distinction between a
+fork and the beginning of a new ridge is clear enough; the islands and
+enclosures are also mostly well marked.
+
+
+[Illustration: PLATE 13.
+
+FIG. 20. V. H. H-D aet. 2-1/2 in 1877, and again as a boy in Nov. 1890.]
+
+
+Plate 13 gives impressions taken from the fingers of a child of 2-1/2
+years in 1877, and again in 1890, when a boy of 15. They are enlarged
+photographically to the same size, and are therefore on different scales.
+The impressions from the baby-hand are not sharp, but sufficiently
+distinct for comparison. Every bifurcation, and beginning or ending of a
+ridge, common to the two impressions, is marked with a numeral in blue
+ink. There is only one island in the present instance, and that is in the
+upper pair of prints; it is clearly seen in the right hand print, lying to
+the left of the inscribed number 13, but the badness of the left hand
+print makes it hardly decipherable, so it is not numbered. There are a
+total of twenty-six good points of comparison common to the upper pair of
+prints; there are forty-three points in the lower pair, forty-two of which
+appear in both, leaving a single point of disagreement; it is marked A on
+the fifth ridge counting from the top. Here a bifurcated ridge in the baby
+is filled up in the boy. This one exception, small though it be, is in my
+experience unique. The total result of the two pairs of prints is to
+afford sixty-eight successes and one failure. The student will find it
+well worth his while to study these and the following prints step by step,
+to satisfy himself of the extraordinarily exact coincidences between the
+two members of either of the pairs. Of course the patterns generally must
+be the same, if the ridges composing them are exactly alike, and the most
+cursory glance shows them to be so.
+
+
+[Illustration: PLATE 14.
+
+FIG. 21.]
+
+
+Plate 14, Fig. 21 contains rather less than a quarter of each of eight
+pairs that were published in the _Phil. Trans._ memoir above alluded to.
+They were there enlarged photographically to twice their natural size,
+which was hardly enough, as it did not allow sufficient space for
+inserting the necessary reference numbers. Consequently they have been
+again considerably enlarged, so much so that it is impossible to put more
+than a portion of each on the page. However, what is given suffices. The
+omitted portions may be studied in the memoir. The cases of ~1~ and ~2~
+are prints of different fingers of the same individual, first as a child 8
+years old, and then as a boy of 17. They have been enlarged on the same
+scale but not to the same size; so the print of the child includes a
+larger proportion of the original impression than that of the boy. It is
+therefore only a part of the child's print which is comparable with that
+of the boy. The remaining six cases refer to four different men, belonging
+to three quite different families, although their surnames happen to have
+the same initial, H. They were adults when the first print was made, and
+from 26 to 31 years older on the second occasion. There is an exact
+agreement throughout between the two members of each of the eight several
+couplets.
+
+In the pair 2. A. E. H. Hl., there is an interesting dot at the point ~4~
+(being an island it deserved to have had two numbers, one for the
+beginning and one for the end). Small as it is, it persists; its growth in
+size corresponding to the growth of the child in stature.
+
+
+[Illustration: PLATE 15.
+
+FIG. 22. RIGHT FOREFINGER OF SIR W. J. H. in 1860 and in 1888.]
+
+
+FIG. 23. DISTRIBUTION OF THE PERIODS OF LIFE, to which the evidence of
+persistency refers.
+
+ +-----------------------------------------------------------------------+
+ | | Age | | Age | Ages, 0--80 years. |
+ |Persons. | at |Interval| at | |
+ | |first| in |second| |
+ | |print| years |print | 10 20 30 40 50 60 70 |
+ |------------------------------------|----|----|----|----|----|----|----|
+ | H. H--d| 2 | 13 | 15 |----+-- | | | | | | |
+ | | | | | | | | | | | | |
+ | A. H--l| 4 | 12 | 16 | ---+--- | | | | | | |
+ | | | | | | | | | | | | |
+ | J. H--l| 8 | 13 | 21 | --+----+ | | | | | |
+ | | | | | | | | | | | | |
+ | E. H--l| 10 | 13 | 23 | |----+-- | | | | | |
+ | | | | | | | | | | | | |
+ |W.J. H--l| 26 | 30 | 56 | | | --+----+----+-- | | |
+ | | | | | | | | | | | | |
+ |R.F. H--n| 26 | 31 | 57 | | | --+----+----+--- | | |
+ | | | | | | | | | | | | |
+ |N.H. T--n| 27 | 28 | 55 | | | -+----+----+-- | | |
+ | | | | | | | | | | | | |
+ |F.H. H--t| 27 | 26 | 53 | | | -+----+----+- | | |
+ | | | | | | | | | | | | |
+ | W. G--e| 62 | 17 | 79 | | | | | | |----+----|
+ +-----------------------------------------------------------------------+
+
+For the sake of those who are deficient in the colour sense and therefore
+hardly able, if at all, to distinguish even the blue numerals in Figs. 20,
+21, I give an eleventh example, Plate 15, Fig. 22, printed all in black.
+The numerals are here very legible, but space for their insertion had to
+be obtained by sacrificing some of the lineations. It is the right
+fore-finger of Sir W. Herschel and has been already published twice; first
+in the account of my lecture at the Royal Institution, and secondly, in
+its present conspicuous form, in my paper in the _Nineteenth Century_. The
+number of years that elapsed between the two impressions is thirty-one,
+and the prints contain twenty-four points of comparison, all of which will
+be seen to agree. I also possess a later print than this, taken in 1890
+from the same finger, which tells the same tale.
+
+The final result of the prints in these pages is that they give
+photographic enlargements of the whole or portions of eleven couplets
+belonging to six different persons, who are members of five unrelated
+families, and which contain between them 158 points of comparison, of
+which only one failed. Adding the portions of the prints that are omitted
+here, but which will be found in the _Phil. Trans._, the material that I
+have thus far published contains 389 points of comparison, of which one
+failed. The details are given in the annexed table:--
+
+ +-----------------------------------------------------------------------+
+ | Order | Initials. |Digit | Age |Dates of| Years | Total points |
+ | in | | of | at |the two |elapsed| of agreement in |
+ | the | |right | date |prints. |between|-------------------|
+ | Figs. | |hand. | of |--------|the two|Figs. 20|Figs. 20, |
+ | | | |first | |prints.|and 21. |22, and in|
+ | | | |print.|1st 2nd| | |Ph. Trans.|
+ |-------|------------|------|------|--------|-------|--------|----------|
+ |FIG. 20| | | | | | | |
+ | 1. |V. H. Hd. |Fore | 2-1/2| 1877-90| 13 | 26 | 26 |
+ | 2. |V. H. Hd. |Ring | 2-1/2| 1877-90| 13 | 42 | 42 |
+ | | | | | | | | |
+ |FIG. 21| | | | | | | |
+ | 1. |A. E. H. Hl.|Fore | 8 | 1881-90| 9 | 11 | 33 |
+ | 2. |A. E. H. Hl.|Ring | 8 | 1881-90| 9 | 5 | 36 |
+ | 3. |N. H. Tn. |Fore |28 | 1862-90| 28 | 6 | 27 |
+ | 4. |N. H. Tn. |Middle|28 | 1862-90| 28 | 10 | 36 |
+ | 5. |F. K. Ht. |Fore |28 | 1862-88| 26 | 12 | 55 |
+ | 6. |R. F. Hn. |Middle|31 | 1859-90| 31 | 6 | 27 |
+ | 7. |W. J. Hl. |Thumb |30 | 1860-90| 30 | 9 | 50 |
+ | 8. |W. J. Hl. |Ring |31 | 1859-90| 31 | 6 | 32 |
+ | | | | | | | | |
+ |FIG. 22| | | | | | | |
+ | 1. |W. J. Hl. |Fore |31 | 1859-90| 31 | 24 | 24 |
+ |---------------------------------------------------|--------|----------|
+ | Total points of agreement | 157 | 388 |
+ | Do. of disagreement | 1 | 1 |
+ +-----------------------------------------------------------------------+
+
+It is difficult to give a just estimate of the number of points of
+comparison that I have studied in other couplets of prints, because they
+were not examined as exhaustively as in these. There were no less than one
+hundred and eleven of them in the ball of the thumb of the child V. H.
+Hd., besides twenty-five in the imperfect prints of his middle and little
+fingers; these alone raise the total of 389 to 525. I must on the whole
+have looked for more than 700 points of comparison, and have found
+agreement in every single case that was examined, except the one already
+mentioned in Fig. 20, of a ridge that was split in the child, but had
+closed up some few years later.
+
+The prints in the two plates cover the intervals from childhood to
+boyhood, from boyhood to early manhood, from manhood to about the age of
+60, and another set--that of Sir W. G.--covers the interval from 67 to 80.
+This is clearly expressed by the diagram (Plate 15, Fig. 23). As there is
+no sign, except in one case, of change during any one of these four
+intervals, which together almost wholly cover the ordinary life of man, we
+are justified in inferring that between birth and death there is
+absolutely no change in, say, 699 out of 700 of the numerous
+characteristics in the markings of the fingers of the same person, such as
+can be impressed by them whenever it is desirable to do so. Neither can
+there be any change after death, up to the time when the skin perishes
+through decomposition; for example, the marks on the fingers of many
+Egyptian mummies, and on the paws of stuffed monkeys, still remain
+legible. Very good evidence and careful inquiry is thus seen to justify
+the popular idea of the persistence of finger markings, that has hitherto
+been too rashly jumped at, and which wrongly ascribed the persistence to
+the general appearance of the pattern, rather than to the minutiae it
+contains. There appear to be no external bodily characteristics, other
+than deep scars and tattoo marks, comparable in their persistence to these
+markings, whether they be on the finger, on other parts of the palmar
+surface of the hand, or on the sole of the foot. At the same time they are
+out of all proportion more numerous than any other measurable features;
+about thirty-five of them are situated on the bulb of each of the ten
+digits, in addition to more than 100 on the ball of the thumb, which has
+not one-fifth of the superficies of the rest of the palmar surface. The
+total number of points suitable for comparison on the two hands must
+therefore be not less than one thousand and nearer to two; an estimate
+which I verified by a rough count on my own hand; similarly in respect to
+the feet. The dimensions of the limbs and body alter in the course of
+growth and decay; the colour, quantity, and quality of the hair, the tint
+and quality of the skin, the number and set of the teeth, the expression
+of the features, the gestures, the handwriting, even the eye-colour,
+change after many years. There seems no persistence in the visible parts
+of the body, except in these minute and hitherto too much disregarded
+ridges.
+
+It must be emphasised that it is in the minutiae, and _not_ in the measured
+dimensions of any portion of the pattern, that this remarkable persistence
+is observed, not even if the measurements be made in units of a
+ridge-interval. The pattern grows simultaneously with the finger, and its
+proportions vary with its fatness, leanness, usage, gouty deformation, or
+age. But, though the pattern as a whole may become considerably altered in
+length or breadth, the number of ridges, their embranchments, and other
+minutiae remain unchanged. So it is with the pattern on a piece of lace.
+The piece as a whole may be stretched in this way, or shrunk in that, and
+its outline altogether altered; nevertheless every one of the component
+threads, and every knot in every thread, can easily be traced and
+identified in both. Therefore, in speaking of the persistence of the marks
+on the finger, the phrase must be taken to apply principally to the
+minutiae, and to the general character of the pattern; not to the measure
+of its length, breadth, or other diameter; these being no more constant
+than the stature, or any other of the ordinary anthropometric data.
+
+
+
+
+CHAPTER VII
+
+EVIDENTIAL VALUE
+
+
+The object of this chapter is to give an approximate numerical idea of the
+value of finger prints as a means of Personal Identification. Though the
+estimates that will be made are professedly and obviously far below the
+truth, they are amply sufficient to prove that the evidence afforded by
+finger prints may be trusted in a most remarkable degree.
+
+Our problem is this: given two finger prints, which are alike in their
+minutiae, what is the chance that they were made by different persons?
+
+The first attempt at comparing two finger prints would be directed to a
+rough general examination of their respective patterns. If they do not
+agree in being arches, loops, or whorls, there can be no doubt that the
+prints are those of different fingers, neither can there be doubt when
+they are distinct forms of the same general class. But to agree thus far
+goes only a short way towards establishing identity, for the number of
+patterns that are promptly distinguishable from one another is not large.
+My earlier inquiries showed this, when endeavouring to sort the prints of
+1000 thumbs into groups that differed each from the rest by an "equally
+discernible" interval. While the attempt, as already mentioned, was not
+successful in its main object, it showed that nearly all the collection
+could be sorted into 100 groups, in each of which the prints had a fairly
+near resemblance. Moreover, twelve or fifteen of the groups referred to
+different varieties of the loop; and as two-thirds of all the prints are
+loops, two-thirds of the 1000 specimens fell into twelve or fifteen
+groups. The chance that an unseen pattern is some particular variety of
+loop, is therefore compounded of 2 to 3 against its being a loop at all,
+and of 1 to 12 or 15, as the case may be, against its being the specified
+kind of loop. This makes an adverse chance of only 2 to 36, or to 45, say
+as 2 to 40, or as 1 to 20. This very rude calculation suffices to show
+that on the average, no great reliance can be placed on a general
+resemblance in the appearance of two finger prints, as a proof that they
+were made by the same finger, though the obvious disagreement of two
+prints is conclusive evidence that they were made by different fingers.
+
+When we proceed to a much more careful comparison, and collate
+successively the numerous minutiae, their coincidence throughout would be
+an evidence of identity, whose value we will now try to appraise.
+
+Let us first consider the question, how far may the minutiae, or groups of
+them, be treated as _independent_ variables?
+
+Suppose that a tiny square of paper of only one average ridge-interval in
+the side, be cut out and dropped at random on a finger print; it will
+mask from view a minute portion of one, or possibly of two ridges. There
+can be little doubt that what was hidden could be correctly interpolated
+by simply joining the ends of the ridge or ridges that were interrupted.
+It is true, the paper might possibly have fallen exactly upon, and hidden,
+a minute island or enclosure, and that our reconstruction would have
+failed in consequence, but such an accident is improbable in a high
+degree, and may be almost ignored.
+
+Repeating the process with a much larger square of paper, say of twelve
+ridge-intervals in the side, the improbability of correctly reconstructing
+the masked portion will have immensely increased. The number of ridges
+that enter the square on any one side will perhaps, as often as not,
+differ from the number which emerge from the opposite side; and when they
+are the same, it does not at all follow that they would be continuous each
+to each, for in so large a space forks and junctions are sure to occur
+between some, and it is impossible to know which, of the ridges.
+Consequently, there must exist a certain size of square with more than one
+and less than twelve ridge-intervals in the side, which will mask so much
+of the print, that it will be an even chance whether the hidden portion
+can, on the average, be rightly reconstructed or not. The size of that
+square must now be considered.
+
+If the reader will refer to Plate 14, in which there are eight much
+enlarged photographs of portions of different finger prints, he will
+observe that the length of each of the portions exceeds the breadth in
+the proportion of 3 to 2. Consequently, by drawing one line down the
+middle and two lines across, each portion may be divided into six squares.
+Moreover, it will be noticed that the side of each of these squares has a
+length of about six ridge-intervals. I cut out squares of paper of this
+size, and throwing one of them at random on any one of the eight portions,
+succeeded almost as frequently as not in drawing lines on its back which
+comparison afterwards showed to have followed the true course of the
+ridges. The provisional estimate that a length of six ridge-intervals
+approximated to but exceeded that of the side of the desired square,
+proved to be correct by the following more exact observations, and by
+three different methods.
+
+I. The first set of tests to verify this estimate were made upon
+photographic enlargements of various thumb prints, to double their natural
+size. A six-ridge-interval square of paper was damped and laid at random
+on the print, the core of the pattern, which was too complex in many cases
+to serve as an average test, being alone avoided. The prints being on
+ordinary albuminised paper, which is slightly adherent when moistened, the
+patch stuck temporarily wherever it was placed and pressed down. Next, a
+sheet of tracing-paper, which we will call No. 1, was laid over all, and
+the margin of the square patch was traced upon it, together with the
+course of the surrounding ridges up to that margin. Then I interpolated on
+the tracing-paper what seemed to be the most likely course of those ridges
+which were hidden by the square. No. 1 was then removed, and a second
+sheet, No. 2, was laid on, and the margin of the patch was outlined on it
+as before, together with the ridges leading up to it. Next, a corner only
+of No. 2 was raised, the square patch was whisked away from underneath,
+the corner was replaced, the sheet was flattened down, and the actual
+courses of the ridges within the already marked outline were traced in.
+Thus there were two tracings of the margin of the square, of which No. 1
+contained the ridges as I had interpolated them, No. 2 as they really
+were, and it was easy to compare the two. The results are given in the
+first column of the following table:--
+
+INTERPOLATION OF RIDGES IN A SIX-RIDGE-INTERVAL SQUARE.
+
+ +---------------------------------------------------------+
+ |Result.| Double |Six-fold scale| Twenty-fold |Total.|
+ | |Enlargements.| with prism. | scale with | |
+ | | | |chequer-work.| |
+ |-------|-------------|--------------|-------------|------|
+ |Right | 12 | 8 | 7 | 27 |
+ |Wrong | 20 | 12 | 16 | 48 |
+ |-------|-------------|--------------|-------------|------|
+ |Total | 32 | 20 | 23 | 75 |
+ +---------------------------------------------------------+
+
+II. In the second method the tracing-papers were discarded, and the prism
+of a camera lucida used. It threw an image three times the size of the
+photo-enlargement, upon a card, and there it was traced. The same general
+principle was adopted as in the first method, but the results being on a
+larger scale, and drawn on stout paper, were more satisfactory and
+convenient. They are given in the second column of the table. In this and
+the foregoing methods two different portions of the same print were
+sometimes dealt with, for it was a little more convenient and seemed as
+good a way of obtaining average results as that of always using portions
+of different finger prints. The total number of fifty-two trials, by one
+or other of the two methods, were made from about forty different prints.
+(I am not sure of the exact number.)
+
+The results in each of the two methods were sometimes quite right,
+sometimes quite wrong, sometimes neither one nor the other. The latter
+depended on the individual judgment as to which class it belonged, and
+might be battled over with more or less show of reason by advocates on
+opposite sides. Equally dividing these intermediate cases between "right"
+and "wrong," the results were obtained as shown. In one, and only one, of
+the cases, the most reasonable interpretation had not been given, and the
+result had been wrong when it ought to have been right. The purely
+personal error was therefore disregarded, and the result entered as
+"right."
+
+III. A third attempt was made by a different method, upon the lineations
+of a finger print drawn on about a twenty-fold scale. It had first been
+enlarged four times by photography, and from this enlargement the axes of
+the ridges had been drawn with a five-fold enlarging pantagraph. The aim
+now was to reconstruct the entire finger print by two successive and
+independent acts of interpolation. A sheet of transparent tracing-paper
+was ruled into six-ridge-interval squares, and every one of its alternate
+squares was rendered opaque by pasting white paper upon it, giving it the
+appearance of a chess-board. When this chequer-work was laid on the print,
+exactly one half of the six-ridge squares were masked by the opaque
+squares, while the ridges running up to them could be seen. They were not
+quite so visible as if each opaque square had been wholly detached from
+its neighbours, instead of touching them at the extreme corners, still the
+loss of information thereby occasioned was small, and not worth laying
+stress upon. It is easily understood that when the chequer-work was moved
+parallel to itself, through the space of one square, whether upwards or
+downwards, or to the right or left, the parts that were previously masked
+became visible, and those that were visible became masked. The object was
+to interpolate the ridges in every opaque square under one of these
+conditions, then to do the same for the remaining squares under the other
+condition, and finally, by combining the results, to obtain a complete
+scheme of the ridges wholly by interpolation. This was easily done by
+using two sheets of tracing-paper, laid in succession over the
+chequer-work, whose position on the print had been changed meanwhile, and
+afterwards tracing the lineations that were drawn on one of the two sheets
+upon the vacant squares of the other. The results are given in the third
+column of the table.
+
+The three methods give roughly similar results, and we may therefore
+accept the ratios of their totals, which is 27 to 75, or say 1 to 3, as
+representing the chance that the reconstruction of any six-ridge-interval
+square would be correct under the given conditions. On reckoning the
+chance as 1 to 2, which will be done at first, it is obvious that the
+error, whatever it may be, is on the safe side. A closer equality in the
+chance that the ridges in a square might run in the observed way or in
+some other way, would result from taking a square of five ridge-intervals
+in the side. I believe this to be very closely the right size. A
+four-ridge-interval square is certainly too small.
+
+When the reconstructed squares were wrong, they had none the less a
+natural appearance. This was especially seen, and on a large scale, in the
+result of the method by chequer-work, in which the lineations of an entire
+print were constructed by guess. Being so familiar with the run of these
+ridges in finger prints, I can speak with confidence on this. My
+assumption is, that any one of these reconstructions represents lineations
+that might have occurred in Nature, in association with the conditions
+outside the square, just as well as the lineations of the actual finger
+print. The courses of the ridges in each square are subject to
+uncertainties, due to petty _local_ incidents, to which the conditions
+outside the square give no sure indication. They appear to be in great
+part determined by the particular disposition of each one or more of the
+half hundred or so sweat-glands which the square contains. The ridges
+rarely run in evenly flowing lines, but may be compared to footways across
+a broken country, which, while they follow a general direction, are
+continually deflected by such trifles as a tuft of grass, a stone, or a
+puddle. Even if the number of ridges emerging from a six-ridge-interval
+square equals the number of those which enter, it does not follow that
+they run across in parallel lines, for there is plenty of room for any one
+of the ridges to end, and another to bifurcate. It is impossible,
+therefore, to know beforehand in which, if in any of the ridges, these
+peculiarities will be found. When the number of entering and issuing
+ridges is unequal, the difficulty is increased. There may, moreover, be
+islands or enclosures in any particular part of the square. It therefore
+seems right to look upon the squares as independent variables, in the
+sense that when the surrounding conditions are alone taken into account,
+the ridges within their limits may either run in the observed way or in a
+different way, the chance of these two contrasted events being taken (for
+safety's sake) as approximately equal.
+
+In comparing finger prints which are alike in their general pattern, it
+may well happen that the proportions of the patterns differ; one may be
+that of a slender boy, the other that of a man whose fingers have been
+broadened or deformed by ill-usage. It is therefore requisite to imagine
+that only one of the prints is divided into exact squares, and to suppose
+that a reticulation has been drawn over the other, in which each mesh
+included the corresponding parts of the former print. Frequent trials have
+shown that there is no practical difficulty in actually doing this, and
+it is the only way of making a fair comparison between the two.
+
+These six-ridge-interval squares may thus be regarded as independent
+units, each of which is equally liable to fall into one or other of two
+alternative classes, when the surrounding conditions are alone known. The
+inevitable consequence from this datum is that the chance of an exact
+correspondence between two different finger prints, in each of the
+six-ridge-interval squares into which they may be divided, and which are
+about 24 in number, is at least as 1 to 2 multiplied into itself 24 times
+(usually written 2{24}), that is as 1 to about ten thousand millions. But
+we must not forget that the six-ridge square was taken in order to ensure
+under-estimation, a five-ridge square would have been preferable, so the
+adverse chances would in reality be enormously greater still.
+
+It is hateful to blunder in calculations of adverse chances, by
+overlooking correlations between variables, and to falsely assume them
+independent, with the result that inflated estimates are made which
+require to be proportionately reduced. Here, however, there seems to be
+little room for such an error.
+
+We must next combine the above enormously unfavourable chance, which we
+will call _a_, with the other chances of not guessing correctly beforehand
+the surrounding conditions under which _a_ was calculated. These latter
+are divisible into _b_ and _c_; the chance _b_ is that of not guessing
+correctly the general course of the ridges adjacent to each square, and
+_c_ that of not guessing rightly the number of ridges that enter and
+issue from the square. The chance _b_ has already been discussed, with the
+result that it might be taken as 1 to 20 for two-thirds of all the
+patterns. It would be higher for the remainder, and very high indeed for
+some few of them, but as it is advisable always to underestimate, it may
+be taken as 1 to 20; or, to obtain the convenience of dealing only with
+values of 2 multiplied into itself, the still lower ratio of 1 to 2{4},
+that is as 1 to 16. As to the remaining chance _c_ with which _a_ and _b_
+have to be compounded, namely, that of guessing aright the number of
+ridges that enter and leave each side of a particular square, I can offer
+no careful observations. The number of the ridges would for the most part
+vary between five and seven, and those in the different squares are
+certainly not quite independent of one another. We have already arrived at
+such large figures that it is surplusage to heap up more of them,
+therefore, let us say, as a mere nominal sum much below the real figure,
+that the chance against guessing each and every one of these data
+correctly is as 1 to 250, or say 1 to 2{8} (= 256).
+
+The result is, that the chance of lineations, constructed by the
+imagination according to strictly natural forms, which shall be found to
+resemble those of a single finger print in all their minutiae, is less than
+1 to 2{24} x 2{4} x 2{8}, or 1 to 2{36}, or 1 to about sixty-four thousand
+millions. The inference is, that as the number of the human race is
+reckoned at about sixteen thousand millions, it is a smaller chance than 1
+to 4 that the print of a _single_ finger of any given person would be
+exactly like that of the same finger of any other member of the human
+race.
+
+When two fingers of each of the two persons are compared, and found to
+have the same minutiae, the improbability of 1 to 2{36} becomes squared,
+and reaches a figure altogether beyond the range of the imagination; when
+three fingers, it is cubed, and so on.
+
+A single instance has shown that the minutiae are _not_ invariably
+permanent throughout life, but that one or more of them may possibly
+change. They may also be destroyed by wounds, and more or less
+disintegrated by hard work, disease, or age. Ambiguities will thus arise
+in their interpretation, one person asserting a resemblance in respect to
+a particular feature, while another asserts dissimilarity. It is therefore
+of interest to know how far a conceded resemblance in the great majority
+of the minutiae combined with some doubt as to the remainder, will tell in
+favour of identity. It will now be convenient to change our datum from a
+six-ridge to a five-ridge square of which about thirty-five are contained
+in a single print, 35 x 5{2} or 35 x 25 being much the same as 24 x 6{2}
+or 24 x 36. The reason for the change is that this number of thirty-five
+happens to be the same as that of the minutiae. We shall therefore not be
+acting unfairly if, with reservation, and for the sake of obtaining some
+result, however rough, we consider the thirty-five minutiae themselves as
+so many independent variables, and accept the chance now as 1 to 2{35}.
+
+This has to be multiplied, as before, into the factor of 2{4} x 2{8}
+(which may still be considered appropriate, though it is too small),
+making the total of adverse chances 1 to 2{47}. Upon such a basis, the
+calculation is simple. There would on the average be 47 instances, out of
+the total 2{47} combinations, of similarity in all but one particular; (47
+x 46)/(1 x 2) in all but two; (47 x 46 x 45)/(1 x 2 x 3) in all but three,
+and so on according to the well-known binomial expansion. Taking for
+convenience the powers of 2 to which these values approximate, or rather
+with the view of not overestimating, let us take the power of 2 that falls
+short of each of them; these may be reckoned as respectively equal to
+2{6}, 2{10}, 2{14}, 2{18}, etc. Hence the roughly approximate chances of
+resemblance in all particulars are as 2{47} to 1; in all particulars but
+one, as 2{47-6}, or 2{41} to 1; in all but two, as 2{37} to 1; in all but
+three, as 2{33} to 1; in all but four, as 2{29} to 1. Even 2{29} is so
+large as to require a row of nine figures to express it. Hence a few
+instances of dissimilarity in the two prints of a single finger, still
+leave untouched an enormously large residue of evidence in favour of
+identity, and when two, three, or more fingers in the two persons agree to
+that extent, the strength of the evidence rises by squares, cubes, etc.,
+far above the level of that amount of probability which begins to rank as
+certainty.
+
+Whatever reductions a legitimate criticism may make in the numerical
+results arrived at in this chapter, bearing in mind the occasional
+ambiguities pictured in Fig. 18, the broad fact remains, that a complete
+or nearly complete accordance between two prints of a single finger, and
+vastly more so between the prints of two or more fingers, affords
+evidence requiring no corroboration, that the persons from whom they were
+made are the same. Let it also be remembered, that this evidence is
+applicable not only to adults, but can establish the identity of the same
+person at any stage of his life between babyhood and old age, and for some
+time after his death.
+
+ * * * * *
+
+We read of the dead body of Jezebel being devoured by the dogs of Jezreel,
+so that no man might say, "This is Jezebel," and that the dogs left only
+her skull, the palms of her hands, and the soles of her feet; but the
+palms of the hands and the soles of the feet are the very remains by which
+a corpse might be most surely identified, if impressions of them, made
+during life, were available.
+
+
+
+
+CHAPTER VIII
+
+PECULIARITIES OF THE DIGITS
+
+
+The data used in this chapter are the prints of 5000 different digits,
+namely, the ten digits of 500 different persons; each digit can thus be
+treated, both separately and in combination, in 500 cases. Five hundred
+cannot be called a large number, but it suffices for approximate results;
+the percentages that it yields may, for instance, be expected to be
+trustworthy, more often than not, within two units.
+
+When preparing the tables for this chapter, I gave a more liberal
+interpretation to the word "Arch" than subsequently. At first, every
+pattern between a Forked-Arch and a Nascent-Loop (Plate 7) was rated as an
+Arch; afterwards they were rated as Loops.
+
+The relative frequency of the three several classes in the 5000 digits was
+as follows:--
+
+ Arches 6.5 per cent.
+ Loops 67.5 "
+ Whorls 26.0 "
+ ------
+ Total 100.0
+
+From this it appears, that on the average out of every 15 or 16 digits,
+one has an arch; out of every 3 digits, two have loops; out of every 4
+digits, one has a whorl.
+
+This coarse statistical treatment leaves an inadequate impression, each
+digit and each hand having its own peculiarity, as we shall see in the
+following table:--
+
+TABLE I.
+
+_Percentage frequency of Arches, Loops, and Whorls on the different
+digits, from observations of the 5000 digits of 500 persons._
+
+ +-----------------------------------------------------------------+
+ | | RIGHT HAND. || LEFT HAND. |
+ | Digit. |-----------------------------------------------------|
+ | |Arch.|Loop.|Whorl.|Total.||Arch.|Loop.| Whorl.|Total.|
+ |-----------+-----------------------------------------------------|
+ |Thumb | 3 | 53 | 44 | 100 || 5 | 65 | 30 | 100 |
+ |Fore-finger| 17 | 53 | 30 | 100 || 17 | 55 | 28 | 100 |
+ |Middle do. | 7 | 78 | 15 | 100 || 8 | 76 | 16 | 100 |
+ |Ring do. | 2 | 53 | 45 | 100 || 3 | 66 | 31 | 100 |
+ |Little do. | 1 | 86 | 13 | 100 || 2 | 90 | 8 | 100 |
+ |-----------+-----+-----+------+------||-----+-----+-------+------|
+ | Total | 30 |323 | 147 | 500 || 35 |352 | 113 | 500 |
+ +-----------------------------------------------------------------+
+
+The percentage of arches on the various digits varies from 1 to 17; of
+loops, from 53 to 90; of whorls, from 13 to 45, consequently the
+statistics of the digits must be separated, and not massed
+indiscriminately.
+
+Are the A. L. W. patterns distributed in the same way upon the
+corresponding digits of the two hands? The answer from the last table is
+distinct and curious, and will be best appreciated on rearranging the
+entries as follows:--
+
+TABLE II.
+
+ +-----------------------------------------------------------------+
+ | | ARCHES. || LOOPS. || WHORLS. |
+ | Digit. |----------------||----------------||----------------|
+ | | Right. | Left. || Right. | Left. || Right. | Left. |
+ |------------|--------|-------||--------|-------||----------------|
+ | Fore-finger| 17 | 17 || 53 | 53 || 30 | 28 |
+ | Middle do. | 7 | 8 || 78 | 76 || 15 | 16 |
+ | Little do. | 1 | 2 || 86 | 90 || 13 | 8 |
+ | | | || | || | |
+ | Thumb | 3 | 5 || 53 | 65 || 44 | 30 |
+ | Ring do. | 2 | 3 || 53 | 66 || 45 | 31 |
+ |------------|--------|-------||--------|-------||----------------|
+ | Total 1000 | 30 | 35 || 323 | 350 || 147 | 113 |
+ +-----------------------------------------------------------------+
+
+The digits are seen to fall into two well-marked groups; the one including
+the fore, middle, and little fingers, the other including the thumb and
+ring-finger. As regards the first group, the frequency with which any
+pattern occurs in any named digit is statistically the same, whether that
+digit be on the right or on the left hand; as regards the second group,
+the frequency differs greatly in the two hands. But though in the first
+group the two fore-fingers, the two middle, and the two little fingers of
+the right hand are severally circumstanced alike in the frequency with
+which their various patterns occur, the difference between the frequency
+of the patterns on a fore, a middle, and a little finger, respectively, is
+very great.
+
+In the second group, though the thumbs on opposite hands do not resemble
+each other in the statistical frequency of the A. L. W. patterns, nor do
+the ring-fingers, there is a great resemblance between the respective
+frequencies in the thumbs and ring-fingers; for instance, the Whorls on
+either of these fingers on the left hand are only two-thirds as common as
+those on the right. The figures in each line and in each column are
+consistent throughout in expressing these curious differences, which must
+therefore be accepted as facts, and not as statistical accidents, whatever
+may be their explanation.
+
+One of the most noticeable peculiarities in Table I. is the much greater
+frequency of Arches on the fore-fingers than on any other of the four
+digits. It amounts to 17 per cent on the fore-fingers, while on the thumbs
+and on the remaining fingers the frequency diminishes (Table III.) in a
+ratio that roughly accords with the distance of each digit from the
+fore-finger.
+
+TABLE III.
+
+ +--------------------------------------------+
+ | _Percentage frequency of Arches._ |
+ |--------------------------------------------|
+ |Hand.|Thumb.| Fore- |Middle | Ring- |Little |
+ | | |finger.|finger.|finger.|finger.|
+ |-----|------|-------|-------|-------|-------|
+ |Right| 3 | 17 | 7 | 2 | 1 |
+ |Left | 5 | 17 | 8 | 3 | 4 |
+ |-----|------|-------|-------|-------|-------|
+ |Mean | 4 | 17 | 7.5 | 2.5 | 2.5 |
+ +--------------------------------------------+
+
+The frequency of Loops (Table IV.) has two maxima; the principal one is on
+the little finger, the secondary on the middle finger.
+
+TABLE IV.
+
+ +--------------------------------------------+
+ | _Percentage frequency of Loops._ |
+ |--------------------------------------------|
+ |Hand.|Thumb.|Fore- |Middle |Ring- |Little |
+ | | |finger.|finger.|finger.|finger.|
+ |-----|------|-------|-------|-------|-------|
+ |Right| 53 | 53 | 78 | 66 | 86 |
+ |Left | 65 | 55 | 76 | 53 | 90 |
+ |-----|------|-------|-------|-------|-------|
+ |Mean | 59 | 54 | 77 | 59.5 | 88 |
+ +--------------------------------------------+
+
+Whorls (Table V.) are most common on the thumb and the ring-finger, most
+rare on the middle and little fingers.
+
+TABLE V.
+
+ +--------------------------------------------+
+ | _Percentage frequency of Whorls._ |
+ |--------------------------------------------|
+ |Hand.|Thumb.|Fore- |Middle |Ring- |Little |
+ | | |finger.|finger.|finger.|finger.|
+ |-----|------|-------|-------|-------|-------|
+ |Right| 44 | 30 | 15 | 45 | 13 |
+ |Left | 30 | 28 | 16 | 31 | 8 |
+ |-----|------|-------|-------|-------|-------|
+ |Mean | 37 | 29 | 15.5 | 38 | 10.5 |
+ +--------------------------------------------+
+
+The fore-finger is peculiar in the frequency with which the direction of
+the slopes of its loops differs from that which is by far the most common
+in all other digits. A loop _must_ have a slope, being caused by the
+disposition of the ridges into the form of a pocket, opening downwards to
+one or other side of the finger. If it opens towards the inner or thumb
+side of the hand, it will be called an inner slope; if towards the outer
+or little-finger side, it will be called an outer slope. In all digits,
+except the fore-fingers, the inner slope is much the more rare of the two;
+but in the fore-fingers the inner slope appears two-thirds as frequently
+as the outer slope. Out of the percentage of 53 loops of the one or other
+kind on the right fore-finger, 21 of them have an inner and 32 an outer
+slope; out of the percentage of 55 loops on the left fore-finger, 21 have
+inner and 34 have outer slopes. These subdivisions 21-21 and 32-34
+corroborate the strong statistical similarity that was observed to exist
+between the frequency of the several patterns on the right and left
+fore-fingers; a condition which was also found to characterise the middle
+and little fingers.
+
+It is strange that Purkenje considers the "inner" slope on the fore-finger
+to be more frequent than the "outer" (p. 86, ~4~). My nomenclature differs
+from his, but there is no doubt as to the disagreement in meaning. The
+facts to be adduced hereafter make it most improbable that the persons
+observed were racially unlike in this particular.
+
+The tendencies of digits to resemble one another will now be considered in
+their various combinations. They will be taken two at a time, in order to
+learn the frequency with which both members of the various couplets are
+affected by the same A. L. W. class of pattern. Every combination will be
+discussed, except those into which the little finger enters. These are
+omitted, because the overwhelming frequency of loops in the little fingers
+would make the results of comparatively little interest, while their
+insertion would greatly increase the size of the table.
+
+TABLE VI_a_.
+
+_Percentage of cases in which the same class of pattern occurs in the_
+same digits _of the two hands_.
+
+(From observation of 5000 digits of 500 persons.)
+
+ +----------------------------------------------------+
+ | Couplets of Digits. |Arches.|Loops.|Whorls.|Total.|
+ |----------------------|-------|------|-------|------|
+ |The two thumbs | 2 | 48 | 24 | 74 |
+ | " fore-fingers | 9 | 38 | 20 | 67 |
+ | " middle fingers| 3 | 65 | 9 | 77 |
+ | " ring-fingers | 2 | 46 | 26 | 74 |
+ |----------------------------------------------------|
+ | Mean of the Totals 72 |
+ +----------------------------------------------------+
+
+TABLE VI_b_.
+
+_Percentage of cases in which the same class of pattern occurs in various
+couplets of_ different digits.
+
+(From 500 persons as above.)
+
+ +-----------------------------------------------------------------------+
+ | Couplets of | OF SAME HANDS. || OF OPPOSITE HANDS. |
+ | Digits. |---------------------------||---------------------------|
+ | |Arch.|Loops.|Whorls.|Total.||Arch.|Loops.|Whorls.|Total.|
+ |--------------|-----|------|-------|------||-----|------|-------|------|
+ |Thumb and | | | | || | | | |
+ | fore-finger | 2 | 35 | 16 | 53 || 2 | 33 | 15 | 50 |
+ |Thumb and | | | | || | | | |
+ | middle finger| 1 | 48 | 9 | 58 || 1 | 47 | 8 | 56 |
+ |Thumb and | | | | || | | | |
+ | ring-finger | 1 | 40 | 20 | 61 || 1 | 38 | 18 | 57 |
+ |Fore and | | | | || | | | |
+ | middle finger| 5 | 48 | 12 | 65 || 5 | 46 | 11 | 62 |
+ |Fore and | | | | || | | | |
+ | ring-finger | 2 | 35 | 17 | 54 || 2 | 35 | 17 | 54 |
+ |Middle and | | | | || | | | |
+ | ring-finger | 2 | 50 | 13 | 65 || 2 | 50 | 12 | 64 |
+ |-----------------------------------------------------------------------|
+ | Means of the Totals 59 || 57 |
+ +-----------------------------------------------------------------------+
+
+A striking feature in this last table is the close similarity between
+corresponding entries relating to the same and to the opposite hands.
+There are eighteen sets to be compared; namely, six couplets of different
+names, in each of which the frequency of three different classes of
+patterns is discussed. The eighteen pairs of corresponding couplets are
+closely alike in every instance. It is worth while to rearrange the
+figures as below, for the greater convenience of observing their
+resemblances.
+
+TABLE VII.
+
+ +---------------------------------------------------------------+
+ | | Arches in || Loops in || Whorls in |
+ | |--------------||--------------||--------------|
+ | Couplet. |Same |Opposite||Same |Opposite||Same |Opposite|
+ | |hand.| hand. ||hand.| hand. ||hand.| hand. |
+ |----------------|-----|--------||-----|--------||-----|--------|
+ |Thumb and | | || | || | |
+ | fore-finger | 2 | 2 || 35 | 33 || 16 | 15 |
+ |Thumb and | | || | || | |
+ | middle finger | 1 | 1 || 48 | 47 || 9 | 8 |
+ |Thumb and ring- | | || | || | |
+ | finger | 1 | 1 || 40 | 38 || 20 | 18 |
+ |Fore and middle | | || | || | |
+ | finger | 5 | 5 || 48 | 46 || 12 | 11 |
+ |Fore and ring- | | || | || | |
+ | finger | 2 | 2 || 35 | 35 || 17 | 17 |
+ |Middle and ring-| | || | || | |
+ | finger | 2 | 2 || 50 | 50 || 13 | 12 |
+ +---------------------------------------------------------------+
+
+The agreement in the above entries is so curiously close as to have
+excited grave suspicion that it was due to some absurd blunder, by which
+the same figures were made inadvertently to do duty twice over, but
+subsequent checking disclosed no error. Though the unanimity of the
+results is wonderful, they are fairly arrived at, and leave no doubt that
+the relationship of any one particular digit, whether thumb, fore, middle,
+ring or little finger, to any other particular digit, is the same, whether
+the two digits are on the same or on opposite hands. It would be a most
+interesting subject of statistical inquiry to ascertain whether the
+distribution of malformations, or of the various forms of skin disease
+among the digits, corroborates this unexpected and remarkable result. I am
+sorry to have no means of undertaking it, being assured on good authority
+that no adequate collection of the necessary data has yet been published.
+
+It might be hastily inferred from the statistical identity of the
+connection between, say, the right thumb and each of the two fore-fingers,
+that the patterns on the two fore-fingers ought always to be alike,
+whether arch, loop, or whorl. If X, it may be said, is identical both with
+Y and with Z, then Y and Z must be identical with one another. But the
+statement of the problem is wrong; X is not identical with Y and Z, but
+only bears an identical amount of statistical resemblance to each of them;
+so this reasoning is inadmissible. The character of the pattern on any
+digit is determined by causes of whose precise nature we are ignorant; but
+we may rest assured that they are numerous and variable, and that their
+variations are in large part independent of one another. We can in
+imagination divide them into groups, calling those that are common to the
+thumb and the fore-finger of either hand, and to those couplets
+exclusively, the A causes; those that are common to the two thumbs and to
+these exclusively, the B causes; and similarly those common to the two
+fore-fingers exclusively, the C causes.
+
+Then the sum of the variable causes determining the class of pattern in
+the four several digits now in question are these:--
+
+ Right thumb A + B + an unclassed residue called X(=1=)
+ Left thumb A + B + " " " X(=2=)
+ Right fore-finger A + C + " " " Z(=1=)
+ Left fore-finger A + C + " " " Z(=2=)
+
+The nearness of relationship between the two thumbs is sufficiently
+indicated by a fraction that expresses the proportion between all the
+causes common to the two thumbs exclusively, and the totality of the
+causes by which the A. L. W. class of the patterns of the thumbs is
+determined, that is to say, by
+
+ A + B
+ ----------------------- (1).
+ A + B + X(=1=) + X(=2=)
+
+Similarly, the nearness of the relationship between the two fore-fingers
+by
+
+ A + C
+ ----------------------- (2).
+ A + C + Z(=1=) + Z(=2=)
+
+And that between a thumb and a fore-finger by
+
+ A
+ --------------------------------------------------- (3).
+ A + B + C + X(=1=) (or X(=2=)) + Z(=1=) (or Z(=2=))
+
+The fractions (1) and (2) being both greater than (3), it follows that the
+relationships between the two thumbs, or between the two fore-fingers, are
+closer than that between the thumb and either fore-finger; at the same
+time it is clear that neither of the two former relationships is so close
+as to reach identity. Similarly as regards the other couplets of digits.
+The tabular entries fully confirm this deduction, for, without going now
+into further details, it will be seen from the "Mean of the Totals" at the
+bottom line of Table VI_b_ that the average percentage of cases in which
+two different digits have the same class of patterns, whether they be on
+the same or on opposite hands, is 59 or 57 (say 58), while the average
+percentage of cases in which right and left digits bearing the same name
+have the same class of pattern (Table VI_a_) is 72. This is barely
+two-thirds of the 100 which would imply identity. At the same time, the 72
+considerably exceeds the 58.
+
+Let us now endeavour to measure the relationships between the various
+couplets of digits on a well-defined centesimal scale, first recalling the
+fundamental principles of the connection that subsists between
+relationships of all kinds, whether between digits, or between kinsmen, or
+between any of those numerous varieties of related events with which
+statisticians deal.
+
+Relationships are all due to the joint action of two groups of variable
+causes, the one common to both of the related objects, the other special
+to each, as in the case just discussed. Using an analogous nomenclature to
+that already employed, the peculiarity of one of the two objects is due to
+an aggregate of variable causes that we may call C+X, and that of the
+other to C+Z, in which C are the causes common to both, and X and Z the
+special ones. In exact proportion as X and Z diminish, and C becomes of
+overpowering effect, so does the closeness of the relationship increase.
+When X and Z both disappear, the result is identity of character. On the
+other hand, when C disappears, all relationship ceases, and the variations
+of the two objects are strictly independent. The simplest case is that in
+which X and Z are equal, and _in this_, it becomes easy to devise a scale
+in which 0 deg. shall stand for no relationship, and 100 deg. for identity, and
+upon which the intermediate degrees of relationship may be marked at their
+proper value. Upon this assumption, but with some misgiving, I will
+attempt to subject the digits to this form of measurement. It will save
+time first to work out an example, and then, after gaining in that way, a
+clearer understanding of what the process is, to discuss its defects. Let
+us select for our example the case that brings out these defects in the
+most conspicuous manner, as follows:--
+
+Table V. tells us that the percentage of whorls in the right ring-finger
+is 45, and in the left ring-finger 31. Table VI_a_ tells us that the
+percentage of the double event of a whorl occurring on both the
+ring-fingers of the same person is 26. It is required to express the
+relationship between the right and left ring-fingers on a centesimal
+scale, in which 0 deg. shall stand for no relationship at all, and 100 deg. for
+the closest possible relationship.
+
+If no relationship should exist, there would nevertheless be a certain
+percentage of instances, due to pure chance, of the double event of whorls
+occurring in both ring-fingers, and it is easy to calculate their
+frequency from the above data. The number of possible combinations of 100
+right ring-fingers with 100 left ones is 100 x 100, and of these 45 x 31
+would be double events as above (call these for brevity "double whorls").
+Consequently the chance of a double whorl in any single couplet is
+(45x31)/(100x100), and their average frequency in 100 couplets,--in other
+words, their average percentage is (45x31)/100 = 13.95, say 14. If, then,
+the observed percentage of double whorls should be only 14, it would be a
+proof that the A. L. W. classes of patterns on the right and left
+ring-fingers were quite independent; so their relationship, as expressed
+on the centesimal scale, would be 0 deg. There could never be less than 14
+double whorls under the given conditions, except through some statistical
+irregularity.
+
+Now consider the opposite extreme of the closest possible relationship,
+subject however, and this is the weak point, to the paramount condition
+that the average frequencies of the A. L. W. classes may be taken as
+_pre-established_. As there are 45 per cent of whorls on the right
+ring-finger, and only 31 on the left, the tendency to form double whorls,
+however stringent it may be, can only be satisfied in 31 cases. There
+remains a superfluity of 14 per cent cases in the right ring-finger which
+perforce must have for their partners either arches or loops. Hence the
+percentage of frequency that indicates the closest feasible relationship
+under the pre-established conditions, would be 31.
+
+The range of all possible relationships in respect to whorls, would
+consequently lie between a percentage frequency of the minimum 14 and the
+maximum 31, while the observed frequency is of the intermediate value of
+26. Subtracting the 14 from these three values, we have the series of 0,
+12, 17. These terms can be converted into their equivalents in a
+centesimal scale that reaches from 0 deg. to 100 deg. instead of from 0 deg. to 17 deg.,
+by the ordinary rule of three, 12:_x_::17:100; _x_=70 or 71, whence the
+value _x_ of the observed relationship on the centesimal scale would be
+70 deg. or 71 deg., neglecting decimals.
+
+This method of obtaining the value of 100 deg. is open to grave objection in
+the present example. We have no right to consider that the 45 per cent of
+whorls on the right ring-finger, and the 31 on the left, can be due to
+pre-established conditions, which would exercise a paramount effect even
+though the whorls were due entirely to causes common to both fingers.
+There is some self-contradiction in such a supposition. Neither are we at
+liberty to assume that the respective effects of the special causes X and
+Z are equal in average amount; if they were, the percentage of whorls on
+the right and on the left finger would invariably be equal.
+
+In this particular example the difficulty of determining correctly the
+scale value of 100 deg. is exceptionally great; elsewhere, the percentages of
+frequency in the two members of each couplet are more alike. In the two
+fore-fingers, and again in the two middle fingers, they are closely alike.
+Therefore, in these latter cases, it is not unreasonable to pass over the
+objection that X and Z have not been proved to be equal, but we must
+accept the results in all other cases with great caution.
+
+When the digits are of different names,--as the thumb and the
+fore-finger,--whether the digits be on the same or on opposite hands,
+there are two cases to be worked out; namely, such as (1) right thumb and
+left fore-finger, and (2) left thumb and right fore-finger. Each accounts
+for 50 per cent of the observed cases; therefore the mean of the two
+percentages is the correct percentage. The relationships calculated in the
+following table do not include arches, except in two instances mentioned
+in a subsequent paragraph, as the arches are elsewhere too rare to furnish
+useful results.
+
+It did not seem necessary to repeat the calculation for couplets of digits
+of different names, situated on opposite hands, as those that were
+calculated on closely the same data for similar couplets situated on the
+same hands, suffice for both. It is evident from the irregularity in the
+run of the figures that the units in the several entries cannot be more
+than vaguely approximate. They have, however, been retained, as being
+possibly better than nothing at all.
+
+TABLE VIII.
+
+_Approximate Measures of Relationship between the various Digits, on a
+Centesimal Scale._
+
+(0 deg. = no relationship; 100 deg. = the utmost feasible likeness.)
+
+ +------------------------------------------------------------+
+ | Couplets. | Loops. | Whorls.| Means. |
+ |---------------------------------|--------|--------|--------|
+ | _Digits of the same name._ | | | |
+ | | | | |
+ | Right and left thumbs | 57 | 64 | 61 |
+ | " " fore-fingers | 37 | 59 | 48 |
+ | " " middle fingers | 34 | 52 | 43 |
+ | " " ring fingers | 61 | 70 | 65 |
+ |---------------------------------|--------|--------|--------|
+ | Means | 47 deg. | 61 deg. | 54 deg. |
+ |---------------------------------|--------|--------|--------|
+ | _Digits of different names on | | | |
+ | the same or on opposite hands._ | | | |
+ | | | | |
+ | Thumb and fore-finger | 19 | 29 | 24 |
+ | " middle finger | 19 | 34 | 27 |
+ | " ring-finger | 33 | 44 | 39 |
+ | Fore and middle finger | 52 | 68 | 60 |
+ | " ring finger | 13 | 34 | 23 |
+ | Middle and ring finger | 31 | 74 | 52 |
+ |---------------------------------|--------|--------|--------|
+ | Means | 28 deg. | 47 deg. | 37 deg. |
+ +------------------------------------------------------------+
+
+The arches were sufficiently numerous in the fore-fingers (17 per cent) to
+fully justify the application of this method of calculation. The result
+was 43 deg., which agrees fairly with 48 deg., the mean of the loops and the
+whorls. In the middle finger the frequency of the arches was only half the
+above amount and barely suffices for calculation. It gave the result of
+38 deg., which also agrees fairly with 43 deg., the mean of the loops and the
+whorls for that finger.
+
+Some definite results may be gathered from this table notwithstanding the
+irregularity with which the figures run. Its upper and lower halves
+clearly belong to different statistical groups, the entries in the former
+being almost uniformly larger than those in the latter, in the proportion
+of 54 deg. to 37 deg., say 3 to 2, which roughly represents in numerical terms the
+nearer relationship between digits of the same name, as compared to that
+between digits of different names. It seems also that of the 6 couplets of
+digits bearing different names, the relationship is closest between the
+middle finger and the two adjacent ones (60 deg. and 52 deg., as against 24 deg., 27 deg.,
+39 deg. and 23 deg.). It is further seen in every pair of entries that whorls are
+related together more closely than loops. I note this, but cannot explain
+it. So far as my statistical inquiries into heredity have hitherto gone,
+all peculiarities were found to follow the same law of transmission, none
+being more surely inherited than others. If there were a tendency in any
+one out of many alternative characters to be more heritable than the rest,
+that character would become universally prevalent, in the absence of
+restraining influences. But it does not follow that there are no peculiar
+restraining influences here, nor that what is true for heredity, should be
+true, in all its details, as regards the relationships between the
+different digits.
+
+
+
+
+CHAPTER IX
+
+METHODS OF INDEXING
+
+
+In this chapter the system of classification by Arches, Loops, and Whorls
+described in Chapter V. will be used for indexing two, three, six or ten
+digits, as the case may be.
+
+An index to each set of finger marks made by the same person, is needful
+in almost every kind of inquiry, whether it be for descriptive purposes,
+for investigations into race and heredity, or into questions of symmetry
+and correlation. It is essential to possess an index to the finger marks
+of known criminals before the method of finger prints can be utilised as
+an organised means of detection.
+
+The ideal index might be conceived to consist of a considerable number of
+compartments, or their equivalents, each bearing a different
+index-heading, into which the sets of finger prints of different persons
+may be severally sorted, so that all similar sets shall lie in the same
+compartment.
+
+The principle of the proposed method of index-headings is, that they
+should depend upon a few conspicuous differences of pattern in many
+fingers, and not upon many minute differences in a few fingers. It is
+carried into effect by distinguishing the A. L. W. class of pattern on
+each digit in succession, by a letter,--_a_ for Arch, _l_ for Loop, _w_
+for Whorl; or else, as an alternative method, to subdivide _l_ by using
+_i_ for a loop with an Inner slope, and _o_ for one with an Outer slope,
+as the case may be. In this way, the class of pattern in each set of ten
+digits is described by a sequence of ten letters, the various combinations
+of which are alphabetically arranged and form the different
+index-headings. Let us now discuss the best method of carrying out this
+principle, by collating the results of alternative methods of applying it.
+We have to consider the utility of the _i_ and _o_ as compared to the
+simple _l_, and the gain through taking all ten digits into account,
+instead of only some of them.
+
+It will be instructive to print here an actual index to the finger prints
+of 100 different persons, who were not in any way selected, but taken as
+they came, and to use it as the basis of a considerable portion of the
+following remarks, to be checked where necessary, by results derived from
+an index to 500 cases, in which these hundred are included.
+
+This index is compiled on the principle shortly to be explained, entitled
+the "_i_ and _o_ fore-finger" method.
+
+TABLE IX.--INDEX TO 100 SETS OF FINGER PRINTS.
+
+ +------------------------------------+
+ | | A B C D |
+ |Order | Right. Left. Rt. Lt. |
+ | of |-----------------------------|
+ |Entry.| F.M.R. F.M.R. T.L. T.L. |
+ |------|-----------------------------|
+ | 1 | _a a a a a a a a l a_ |
+ | 2 | _ " " a l a l_ |
+ | 3 | _ " " " " _ |
+ | 4 | _ " " w l l l_ |
+ | 5 | _a a l a a l a l a l_ |
+ | 6 | _ " " l l l l_ |
+ | 7 | _ " " " " _ |
+ | 8 | _ " a a w l l l l_ |
+ | 9 | _ " a l l l l l l_ |
+ | 10 | _ " " l w w l_ |
+ | 11 | _ " o l l l l l l_ |
+ | 12 | _a a w a a l l l l l_ |
+ | 13 | _ " a l l l l l l_ |
+ | 14 | _a l a a a a l a l a_ |
+ | 15 | _ " " l a l w_ |
+ | 16 | _ " o l l w l l l_ |
+ | 17 | _a l l a a l l l a l_ |
+ | 18 | _ " " l l l l_ |
+ | 19 | _ " " " " _ |
+ | 20 | _ " " " " _ |
+ | 21 | _ " " " " _ |
+ | 22 | _ " " " " _ |
+ | 23 | _ " a l w l l l l_ |
+ | 24 | _ " i l l l l l l_ |
+ | 25 | _ " " " " _ |
+ | 26 | _a l l i l l w l l l_ |
+ | 27 | _ " o a l w l l l_ |
+ | 28 | _ " o l l w l l l_ |
+ | 29 | _ " w w w w l l l_ |
+ | 30 | _a l w i l w l l l l_ |
+ | 31 | _ " o a l l l l l_ |
+ | 32 | _ " o l l l w l l_ |
+ | 33 | _ " " w l w l_ |
+ | 34 | _ " o l w a l a l_ |
+ | 35 | _i l l a l l w l l l_ |
+ | 36 | _ " " w l w l_ |
+ | 37 | _ " i l l l l l l_ |
+ | 38 | _ " " " " _ |
+ | 39 | _ " " " " _ |
+ | 40 | _ " " " " _ |
+ | 41 | _i l l i l l w l l l_ |
+ | 42 | _ " i w w w l w l_ |
+ | 43 | _i l w i l l l l w l_ |
+ | 44 | _ " " w w w l_ |
+ | 45 | _ " i l w w w w l_ |
+ | 46 | _ " i w l l l l l_ |
+ | 47 | _ " w l w w l w l_ |
+ | 48 | _ " w w l l l l l_ |
+ | 49 | _i w w a l l w l w l_ |
+ | 50 | _ " w w w w l w l_ |
+ | 51 | _ " " " " _ |
+ | 52 | _o a w o l l l l l l_ |
+ | 53 | _o l l o l l l l l l_ |
+ | 54 | _ " " " " _ |
+ | 55 | _ " " " " _ |
+ | 56 | _ " " w l w l_ |
+ | 57 | _ " i l l l l l l_ |
+ | 58 | _ " " " " _ |
+ | 59 | _ " " " " _ |
+ | 60 | _ " o l l l l l l_ |
+ | 61 | _ " " " " _ |
+ | 62 | _ " " " " _ |
+ | 63 | _ " " " " _ |
+ | 64 | _ " " " " _ |
+ | 65 | _ " " " " _ |
+ | 66 | _ " w a l l l w l_ |
+ | 67 | _ " w w w l l w l_ |
+ | 68 | _o l w a l l l l l l_ |
+ | 69 | _ " " w l w l_ |
+ | 70 | _ " i l l w l w l_ |
+ | 71 | _ " o l l l l l l_ |
+ | 72 | _ " " " " _ |
+ | 73 | _ " o l w l l l l_ |
+ | 74 | _ " " " " _ |
+ | 75 | _w l l i l l l l w l_ |
+ | 76 | _ " " " " _ |
+ | 77 | _w l l w l l l l l l_ |
+ | 78 | _ " " " " _ |
+ | 79 | _ " " w l w l_ |
+ | 80 | _ " w l w l l l l_ |
+ | 81 | _w l w o l w l l l l_ |
+ | 82 | _ " " l l a l_ |
+ | 83 | _ " " w l l l_ |
+ | 84 | _ " w w w w l w l_ |
+ | 85 | _ " " w w l l_ |
+ | 86 | _ " " w w l w_ |
+ | 87 | _ " " w w w w_ |
+ | 88 | _ " " " " _ |
+ | 89 | _w w l i l l l l l l_ |
+ | 90 | _ " w l l w l l l_ |
+ | 91 | _w w w o l w w l l l_ |
+ | 92 | _ " w l w w l w l_ |
+ | 93 | _ " " " " _ |
+ | 94 | _ " w w l l l l w_ |
+ | 95 | _ " w w w i l l l_ |
+ | 96 | _ " " w l l l_ |
+ | 97 | _ " " w l w l_ |
+ | 98 | _ " " w w w l_ |
+ | 99 | _ " " " " _ |
+ | 100 | _ " " w w w w_ |
+ +------------------------------------+
+
+The sequence in which the digits have been registered is not from the
+thumb outwards to the little finger, but, on account of various good
+reasons that will be appreciated as we proceed, in the following order.
+
+The ten digits are registered in four groups, which are distinguished in
+the Index by the letters A, B, C, D:--
+
+ A. _First._ The fore, middle, and ring-fingers of the _right_ hand
+ taken in that order.
+
+ B. _Second._ The fore, middle, and ring-fingers of the _left_ hand
+ taken in that order.
+
+ C. _Third._ The thumb and little finger of the _right_ hand.
+
+ D. _Fourth._ The thumb and little finger of the _left_ hand.
+
+Consequently an index-heading will be of the form--
+
+ First Second Third Fourth
+ group. group. group. group.
+
+ _a a l_ _a a w_ _l l_ _l l_
+
+These index-headings are catalogued in alphabetical order. The method used
+in the Index is that which takes note of no slopes, except those of loops
+in the fore-finger of either hand. Consequently the index-heading for my
+own digits, printed on the title-page, is _wlw oll wl wl_. Those of the
+eight sets in Plate VI. are as follows:--
+
+ _i l w i l l w w w l_
+ _o l w o l w w l l l_
+ _o l w o l w w l l l_
+ _o l w o l l l l l l_
+ _i l w i l w w l w l_
+ _i l w i w l l l l l_
+ _i l l w w l l l l l_
+ _o l l a a l l l a l_
+ _o a a a a a l a l a_
+
+For convenience of description and reference, the successive entries in
+the specimen index have been numbered from 1 to 100, but that is no part
+of the system: those figures would be replaced in a real index by names
+and addresses.
+
+A preliminary way of obtaining an idea of the differentiating power of an
+index is to count the number of the different headings that are required
+to classify a specified number of cases. A table is appended which shows
+the numbers of the headings in the three alternative methods (1) of noting
+slopes of all kinds in all digits, (2) of noting slopes of Loops only and
+in the fore-fingers only, and (3) of disregarding the slopes altogether.
+Also in each of these three cases taking account of--
+
+ (_a_) All the ten digits;
+
+ (_b_) the fore, middle, and ring-fingers of both hands;
+
+ (_c_) those same three fingers, but of the right hand only;
+
+ (_d_) the fore and middle fingers of the right hand.
+
+TABLE X.
+
+_No. of different index-heads in 100 sets of Finger Prints._
+
+ +---------------------------------------------------------------+
+ | | | Account taken of |
+ | No. of | |------------------------------|
+ | digits | Digits noted. | All |_i_ and _o_| No |
+ | regarded. | | slopes. | in fore- | slope. |
+ | | | | fingers. | |
+ |-----------|--------------------|---------|-----------|--------|
+ | 10 | All the 10 digits | 82 | 76 | 71 |
+ | | | | | |
+ | | Fore, middle, | | | |
+ | 6 | and ring-fingers | 65 | 50 | 43 |
+ | | of both hands | | | |
+ | | | | | |
+ | 3 | Of right hand only | 25 | 16 | 14 |
+ | | | | | |
+ | 2 | Fore and middle of | 12 | 8 | 7 |
+ | | right hand only | | | |
+ +---------------------------------------------------------------+
+
+The column headed "all slopes" refers to the method first used with
+success, and described in my Memoir, already alluded to (_Proc. Roy.
+Soc._, 1891), accompanied by a specimen index, from which the present one
+was derived. There the direction of the slope of every pattern that has
+one, is taken into account, and in order to give as much scope as
+possible to the method, the term Arch (I then called it a Primary) was
+construed somewhat over-liberally (see p. 114). It was made to include the
+forked-arch Fig. 12 (~2~), and even the nascent-loop (~9~), so long as not
+more than a single recurved ridge lay within the outline of the pattern;
+therefore many of the so-called arches had slopes. It is not necessary to
+trouble the reader with the numerical nomenclature that was then used, the
+method itself being now obsolete. Full particulars of it are, however,
+given in the Memoir.
+
+A somewhat large experience in sorting finger prints in various ways and
+repeatedly, made it only too evident that the mental strain and risk of
+error caused by taking all slopes into account was considerable. The
+judgment became fatigued and the eye puzzled by having to assign opposite
+meanings to the same actual direction of a slope in the right and left
+hands respectively. There was also a frequent doubt as to the existence of
+a slope in large whorls of the spiral- and circlet-in-loop patterns (Fig.
+13, ~21~, ~22~) when the impressions had not been rolled. A third
+objection is the rarity of the inner slopes in any other digit than the
+fore-finger. It acted like a soporific to the judgment not only of myself
+but of others, so that when an inner slope did occur it was apt to be
+overlooked. The first idea was to discard slopes altogether,
+notwithstanding the accompanying loss of index power, but this would be an
+unnecessarily trenchant measure. The slope of a loop, though it be on the
+fore-finger alone, decidedly merits recognition, for it differentiates
+such loops into two not very unequal classes. Again, there is little
+chance of mistake in noting it, the impression of the thumb on the one
+side and those of the remaining fingers on the other, affording easy
+guidance to the eye and judgment. These considerations determined the
+method I now use exclusively, by which Table IX. was compiled, and to
+which the second column of Table X., headed "_i_ and _o_ in fore-fingers,"
+refers.
+
+The heading of the third column, "no slope," explains itself, no account
+having been there taken of any slopes whatever, so _i_ and _o_ disappear,
+having become merged under _l_.
+
+The table gives a very favourable impression of the differentiating power
+of all these methods of indexing. By the "_i_ and _o_ fore-finger" method,
+it requires as many as 76 different index-headings to include the finger
+prints of 100 different persons, 195 of 300 persons, and 285 of 500.
+
+The number of entries under each index-heading varies greatly; reference
+to the index of 100 sets showing no less than six entries (Nos. 60-65)
+under one of them, and four entries (Nos. 18-21 and 37-40) under each of
+two others. Thus, although a large portion of the 100 sets are solitary
+entries under their several headings, and can be found by a single
+reference, the remainder are grouped together like the commoner surnames
+in a directory. They are troublesome to distinguish, and cannot be
+subdivided at all except by supplementary characteristics, such as the
+number of ridges in some specified part of the pattern, or the character
+of the cores.
+
+In other respects the difference of merit between the three methods is
+somewhat greater, as is succinctly indicated by the next table.
+
+TABLE XI.--_In 100 Sets._
+
+ +-----------------------------------------------------+
+ | |No. of different index-headings.|
+ | Number of Entries |--------------------------------|
+ |under the same head.| All | _i_ and _o_ | No |
+ | | slopes. | fore-fingers | slope.|
+ | | | only. | |
+ |--------------------|---------|--------------|-------|
+ | 1 | 71 | 63 | 58 |
+ | 2 | 10 | 8 | 9 |
+ | 3 | 1 | 3 | 1 |
+ | 4 | ... | 2 | 2 |
+ | 5 | ... | ... | ... |
+ | 6 | 1 | ... | ... |
+ | 13 | ... | ... | 1 |
+ |--------------------|---------|--------------|-------|
+ | Total | 83 | 76 | 71 |
+ +-----------------------------------------------------+
+
+Hence it is evident that the second method of "_i-o_ fore-finger" is
+capable of dealing rapidly with 100 cases, but that the method of "no
+slope" will give trouble in twelve out of the hundred cases.
+
+TABLE XII.
+
+_Index-headings under which more than 1 per cent of the sets of Finger
+Prints were registered._
+
+(500 sets observed.)
+
+ +----------------------------------------------------
+ | _i_ and _o_ in fore-fingers. ||
+ |----------------------------------------------------
+ | No. | |Frequency||
+ | for | Index-heading. | per ||
+ |Reference.| | cent. ||
+ |----------|-----------------------------|---------||
+ | 1 | _a l l a l l l l l l_ | 1.2 ||
+ | 2 | _a l l i l l " " _ | 1.6 ||
+ |----------|-----------------------------|---------||
+ | 3 | _i l l i l l " " _ | 2.8 ||
+ | 4 | _o l l i l l " " _ | 1.4 ||
+ | 5 | _o l l o l l " " _ | 4.0 ||
+ |----------|-----------------------------|---------||
+ | 6 | _i l l o l l w l l l_ | 1.2 ||
+ | 7 | _o l l o l l " " _ | 1.4 ||
+ |----------|-----------------------------|---------||
+ | 8 | _o l l a l l l l l l_ | 2.2 ||
+ | 9 | _o l w u l l " " _ | 2.0 ||
+ | 10 | _w l l w l l " " _ | 1.2 ||
+ | 11 | _w w w w w w w w w w_ | 1.4 ||
+ +----------------------------------------------------
+
+ --------------------------------------------------+
+ No slope. |
+ --------------------------------------------------|
+ No. | |Frequency|
+ for | Index-heading. | per |
+ Reference.| | cent. |
+ ----------|-----------------------------|---------|
+ I. | _a l l a l l l l l l_ | 1.2 |
+ II. | _a l l l l l " " _ | 2.2 |
+ ----------|-----------------------------|---------|
+ | | |
+ III. | _l l l l l l " " _ | 9.2 |
+ | | |
+ ----------|-----------------------------|---------|
+ IV. | _l l l l l l w l l l_ | 3.2 |
+ | | |
+ ----------|-----------------------------|---------|
+ V. | _l l l a l l l l l l_ | 3.0 |
+ VI. | _l l w l l l " " _ | 3.0 |
+ VII. | _w l l w l l " " _ | 1.2 |
+ VIII. | _w w w w w w w w w w_ | 1.4 |
+ --------------------------------------------------+
+
+ The headings in the right half of the table include more cases than
+ the left half, because a combination of two or more cases that
+ severally contain less than 1 per cent of the finger prints, and are
+ therefore ignored in the first half of the table, may exceed 1 per
+ cent and find a place in the second half.
+
+The entries in Table XII. are derived from a catalogue of 500 sets, and
+include all entries that appeared more than five times; in other words,
+whose frequency exceeded 1 per cent. These are the index-headings that
+give enough trouble to deserve notice in catalogues of, say, from 500 to
+1000 sets.
+
+In the left half of Table XII. all the index-headings are given, under
+each of which more than 1 per cent of the sets fell, when the method of
+"_i_ and _o_ in fore-fingers" was adopted; also the respective percentage
+of the cases that fell under them. In the right half of the table are the
+corresponding index-headings, together with the percentages of frequency,
+when the "no slope" method is employed. These are distinguished by Roman
+numerals. The great advantage of the "_i_ and _o_ fore-finger" method lies
+in its power of breaking up certain large groups which are very
+troublesome to deal with by the "no slope" method. According to the latter
+as many as 9.2 per cent of all the entries fall under the index-heading
+marked III., but according to the "_i-o_ fore-finger" method these are
+distributed among the headings 3, 4, and 5. The "all slopes" method has
+the peculiar merit of breaking up the large group Nos. 11 and VIII. of
+"all whorls," but its importance is not great on that account, as whorls
+are distinguishable by their cores, which are less troublesome to observe
+than their slopes.
+
+The percentage of all the entries that fall under a single index-heading,
+according to the "_i-o_ fore-finger" method, diminishes with the number of
+entries at the following rate:--
+
+TABLE XIII.
+
+ +----------------------------------------------------------+
+ | | Total number of entries. |
+ | |--------------------------|
+ | | 100 | 300 | 500 |
+ |-------------------------------|--------|--------|--------|
+ | Percentage of entries falling | | | |
+ | under a single head | 63 | 49.0 | 39.8 |
+ +----------------------------------------------------------+
+
+It may be that every one of the 4{2} x 3{8}, or one hundred and five
+thousand possible varieties of index-headings, according to the "_i-o_
+fore-finger" method, may occur in Nature, but there is much probability
+that some of them may be so rare that instances of no entry under certain
+heads would appear in the register, even of an enormous number of persons.
+
+ * * * * *
+
+Hitherto we have supposed that prints of the ten fingers have in each case
+been indexed. The question now to be considered is the gain through
+dealing in each case with all ten digits, instead of following the easier
+practice of regarding only a few of them. The following table, drawn up
+from the hundred cases by the "all slopes" method, will show its amount.
+
+TABLE XIV.--_From 100 Sets._
+
+ +----------------------------------------------------------------------+
+ | | | No. of different index-headings. |
+ | Digits. | No. of |------------------------------------|
+ | | digits. | All | _i_ and _o_ | No slope. |
+ | | | slopes. | fore-finger. | |
+ |-----------------------|---------|---------|--------------|-----------|
+ | Fore and middle of | | | | |
+ | right hand | 2 | 11 | 8 | 7 |
+ | | | | | |
+ | Fore, middle and ring | | | | |
+ | of right hand | 3 | 23 | 16 | 14 |
+ | | | | | |
+ | Fore, middle and ring | | | | |
+ | of both hands | 6 | 65 | 50 | 45 |
+ | | | | | |
+ | All ten digits | 10 | 83 | 76 | 73 |
+ +----------------------------------------------------------------------+
+
+The trouble of printing, reading off, and indexing the ten digits, is
+practically twice that of dealing with the six fingers; namely, three on
+each of the hands; the thumb being inconvenient to print from, and having
+to be printed separately, even for a dabbed impression, while the fingers
+of either hand can be dabbed down simultaneously.
+
+For a large collection the ten digit method is certainly the best, as it
+breaks up the big battalions; also in case of one or more fingers having
+been injured, it gives reserve material to work upon.
+
+ * * * * *
+
+We now come to the great difficulty in all classifications; that of
+transitional cases. What is to be done with those prints which cannot be
+certainly classed as Arches, Loops, or Whorls, but which lie between some
+two of them? These occur about once in every forty digits, or once in
+every four pairs of hands. The roughest way is to put a mark by the side
+of the entry to indicate doubt, a better one is to make a mark that shall
+express the nature of the peculiarity; thus a particular eyed pattern
+(Plate 10, Fig. 16, _n_) may be transitional between a loop and a whorl;
+under whichever of the two it is entered, the mark might be an _e_ to show
+that anyhow it is an eye. Then, when it is required to discover whether an
+index contains a duplicate of a given specimen in which a transitional
+pattern occurs, the two headings between which the doubt lies have to be
+searched, and the marked entries will limit the search. Many alternative
+ways of marking may be successfully used, but I am not yet prepared to
+propose one as being distinctly the best. When there are two of these
+marks in the same set, it seldom happens that more than two references
+have to be made, as it is usual for the ambiguity to be of the same kind
+in both of the doubtful fingers. If the ambiguities were quite
+independent, then two marks would require four references, and three marks
+would require nine. There are a few nondescript prints that would fall
+under a separate heading, such as Z. Similarly, as regards lost or injured
+fingers.
+
+I have tried various methods of sub-classification, and find no difficulty
+in any of them, but general rules seem inadvisable; it being best to treat
+each large group on its own merits.
+
+One method that I have adopted and described in the _Proc. Royal Soc._, is
+to sketch in a cursive and symbolic form the patterns of the several
+fingers in the order in which they appear in the print, confining myself
+to a limited number of symbols, such as might be used for printer's types.
+They sufficed fairly for some thousands of the finger marks upon which
+they were tried, but doubtless they could be improved. A little violence
+has of course to be used now and then, in fitting some unusual patterns to
+some one or other of these few symbols. But we are familiar with such
+processes in ordinary spelling, making the same letter do duty for
+different sounds, as _a_ in the words _as_, _ale_, _ask_, and _all_. The
+plan of using symbols has many secondary merits. It facilitates a
+leisurely revision of first determinations, it affords a pictorial record
+of the final judgment that is directly comparable with the print itself,
+and it almost wholly checks blunders between inner and outer slopes. A
+beginner in finger reading will educate his judgment by habitually using
+them at first.
+
+
+[Illustration: PLATE 2.
+
+FIG. 3. Form of card used for impressions of the ten digits. 11-1/2 x 5
+inches.
+
+FIG. 4. Roller and its bearings, of a pocket printing apparatus.]
+
+
+The cores give great assistance in breaking up the very large groups of
+all-loops (see Table XII., Nos. 11 and VIII.); so does an entry of the
+approximate number of ridges in some selected fingers, that lie between
+the core and the upper outline of the loop.
+
+ * * * * *
+
+The plan I am now using for keeping finger prints in regular order, is
+this:--In the principal collection, the prints of each person's ten digits
+are taken on the same large card; the four fingers of either hand being
+_dabbed_ down simultaneously above, and all the ten digits _rolled_
+separately below. (Plate 2, Fig. 3.) Each card has a hole three-eighths of
+an inch in diameter, punched in the middle near to the bottom edge, and
+the cards are kept in trays, which they loosely fit, like the card
+catalogues used in many libraries. Each tray holds easily 500 cards, which
+are secured by a long stout wire passing like a skewer through the ends of
+the box and the holes in the cards. The hinder end of the box is sloped,
+so the cards can be tilted back and easily examined; they can be inserted
+or removed after withdrawing the wire.
+
+It will be recollected that the leading and therefore the most conspicuous
+headings in the index refer to the fore, middle, and ring-fingers of the
+right hand, as entered in column A of the Specimen Register (Table IX.)
+The variety of these in the "_i_ and _o_ fore-finger" method, of which we
+are now speaking, cannot exceed thirty-six, there being only four
+varieties (_a_, _i_, _o_, _w_) in the fore-finger, and three varieties
+(_a_, _l_, _w_) in each of the other two; so their maximum number is 4 x 3
+x 3 = 36. The actual number of such index-headings in 500 cases, and the
+number of entries that fell under each, was found to be as follows:--
+
+TABLE XV.
+
+_No. of entries in 500 cases, under each of the thirty-six possible
+index-letters for the fore, middle, and ring-fingers of the right hand by
+the "i-o fore-finger" method._
+
+ +--------------------------------------------------------------+
+ | _a a a_ | 4 || _i a a_ | 1 || _o a a_ | 1 || _w a a_ | -- |
+ | _l_ | 17 || _l_ | 3 || _l_ | 2 || _l_ | -- |
+ | _w_ | 5 || _w_ | -- || _w_ | 1 || _w_ | 1 |
+ | | || | || | || | |
+ | _a l a_ | 3 || _i l a_ | -- || _o l a_ | 2 || _w l a_ | 1 |
+ | _l_ | 45 || _l_ | 54 || _l_ | 88 || _l_ | 40 |
+ | _w_ | 11 || _w_ | 33 || _w_ | 59 || _w_ | 52 |
+ | | || | || | || | |
+ | _a w a_ | -- || _i w a_ | -- || _o w a_ | -- || _w w a_ | -- |
+ | _l_ | -- || _l_ | 3 || _l_ | -- || _l_ | 10 |
+ | _w_ | -- || _w_ | 11 || _w_ | 6 || _w_ | 47 |
+ +--------------------------------------------------------------+
+
+ _a_ = Arch.
+
+ _i_ = Inward-sloped Loop on the fore-finger.
+
+ _o_ = Outward-sloped Loop on the fore-finger.
+
+ _l_ = Loop of either kind on the middle or ring finger.
+
+ _w_ = Whorl.
+
+These 500 cases supply no entries at all to eleven of the thirty-six
+index-headings, less than five entries (or under 1 per cent) to ten
+others, and the supply is distributed very unevenly among the remaining
+fifteen. This table makes it easy to calculate beforehand the spaces
+required for an index of any specified number of prints, whether they be
+on the pages of a Register, or in compartments, or in drawers of movable
+cards.
+
+
+
+
+CHAPTER X
+
+PERSONAL IDENTIFICATION
+
+
+We shall speak in this chapter of the aid that finger prints can give to
+personal identification, supposing throughout that facilities exist for
+taking them well and cheaply, and that more or less practice in reading
+them has been acquired by many persons. A few introductory words will show
+this supposition to be reasonable. At the present moment any printer, and
+there are many printers in every town, would, at a small charge, blacken a
+slab and take the prints effectively, after being warned to use very
+little ink, as described in Chapter III. The occupation of finger printing
+would, however, fall more naturally into the hands of photographers, who,
+in addition to being found everywhere, are peculiarly well suited to it,
+for, taken as a class, they are naturally gifted with manual dexterity and
+mechanical ingenuity. Having secured good impressions, they could multiply
+them when necessary, and enlarge when desired, while the ticketing and
+preservation of the negatives would fall into their usual business
+routine. As they already occupy themselves with one means of
+identification, a second means of obtaining the same result is allied to
+their present work.
+
+Were it the custom for persons about to travel to ask for prints of their
+fingers when they were photographed, a familiarity with the peculiarities
+of finger prints, and the methods of describing and classifying them,
+would become common. Wherever finger prints may be wanted for purposes of
+attestation and the like, the fact mentioned by Sir W. Herschel (p. 45) as
+to the readiness with which his native orderlies learnt to take them with
+the ink of his office stamp, must not be forgotten.
+
+The remarks about to be made refer to identification generally, and are
+not affected by the fact that the complete process may or may not include
+the preliminary search of a catalogue; the two stages of search and of
+comparison will be treated separately towards the close of the chapter.
+
+In civilised lands, honest citizens rarely need additional means of
+identification to their signatures, their photographs, and to personal
+introductions. The cases in which other evidence is wanted are chiefly
+connected with violent death through accident, murder, or suicide, which
+yield the constant and gruesome supply to the Morgue of Paris, and to
+corresponding institutions in other large towns, where the bodies of
+unknown persons are exposed for identification, often in vain. But when
+honest persons travel to distant countries where they have few or no
+friends, the need for a means of recognition is more frequently felt. The
+risk of death through accident or crime is increased, and the probability
+of subsequent identification diminished. There is a possibility not too
+remote to be disregarded, especially in times of war, of a harmless person
+being arrested by mistake for another man, and being in sore straits to
+give satisfactory proof of the error. A signature may be distrusted as a
+forgery. There is also some small chance, when he returns to his own
+country after a long absence, of finding difficulty in proving who he is.
+But in civilised lands and in peaceable times, the chief use of a sure
+means of identification is to benefit society by detecting rogues, rather
+than to establish the identity of men who are honest. Is this criminal an
+old offender? Is this new recruit a deserter? Is this professed pensioner
+personating a man who is dead? Is this upstart claimant to property the
+true heir, who was believed to have died in foreign lands?
+
+In India and in many of our Colonies the absence of satisfactory means for
+identifying persons of other races is seriously felt. The natives are
+mostly unable to sign; their features are not readily distinguished by
+Europeans; and in too many cases they are characterised by a strange
+amount of litigiousness, wiliness, and unveracity. The experience of Sir
+W. Herschel, and the way in which he met these unfavourable conditions by
+the method of finger prints, has been briefly described in p. 27. Lately
+Major Ferris, of the Indian Staff Corps, happening to visit my laboratory
+during my absence, and knowing but little of what Sir W. Herschel had
+done, was greatly impressed by the possibilities of finger prints. After
+acquainting himself with the process, we discussed the subject together,
+and he very kindly gave me his views for insertion here. They are as
+follow, with a few trifling changes of words:--
+
+ "During a period of twenty-three years, eighteen of which have been
+ passed in the Political Department of the Bombay Government, the great
+ need of an official system of identification has been constantly
+ forced on my mind.
+
+ "The uniformity in the colour of hair, eyes, and complexion of the
+ Indian races renders identification far from easy, and the difficulty
+ of recording the description of an individual, so that he may be
+ afterwards recognised, is very great. Again, their hand-writing,
+ whether it be in Persian or Devanagri letters, is devoid of character
+ and gives but little help towards identification.
+
+ "The tenacity with which a native of India cleaves to his ancestral
+ land, his innate desire to acquire more and more, and the obligation
+ that accrues to him at birth of safeguarding that which has already
+ been acquired, amounts to a religion, and passes the comprehension of
+ the ordinary Western mind. This passion, or religion, coupled with a
+ natural taste for litigation, brings annually into the Civil Courts an
+ enormous number of suits affecting land. In a native State at one time
+ under my political charge, the percentage of suits for the possession
+ of land in which the title was disputed amounted to no less than 92,
+ while in 83 per cent of these the writing by which the transfer of
+ title purported to have been made, was repudiated by the former
+ title-holder as fraudulent and not executed by him. When it is
+ remembered that an enormous majority of the landholders whose titles
+ come into court are absolutely illiterate, and that their execution of
+ the documents is attested by a mark made by a third party, frequently,
+ though not always apparently, interested in the transfer, it will be
+ seen that there is a wide door open to fraud, whether by false
+ repudiation or by criminal attempt at dispossession.
+
+ "It has frequently happened in my experience that a transfer of title
+ or possession was repudiated; the person purporting to have executed
+ the transfer asserting that he had no knowledge of it, and never
+ authorised any one to write, sign, or present it for registration.
+ This was met by a categorical statement on the part of the beneficiary
+ and of the attesting witnesses, concerning the time, date, and
+ circumstances of the execution and registration, that demolished the
+ simple denial of the man whom it was sought to dispossess. Without
+ going into the ethics of falsehood among Western and Eastern peoples,
+ it would be impossible to explain how what is repugnant to the one as
+ downright lying, is very frequently considered as no more than venial
+ prevarication by the other. This, however, is too large a subject for
+ present purposes, but the fact remains that perjury is perpetrated in
+ Indian Courts to an extent unknown in the United Kingdom.
+
+ "The interests of landholders are partially safeguarded by the Act
+ that requires all documents effecting the transfer of immovable
+ property to be registered, but it could be explained, though not in
+ the short space of this letter, how the provisions of the Act can be,
+ and frequently are, fulfilled in the absence of the principal person,
+ the executor.
+
+ "Enough has been said to show that if some simple but efficient means
+ could be contrived to identify the person who has executed a bond,
+ cases of fraud such as these would practically disappear from the
+ judicial registers. Were the legislature to amend the Registration Act
+ and require that the original document as well as the copy in the
+ Registration Book should bear the imprint of one or more fingers of
+ the parties to the deed, I have little hesitation in saying that not
+ only would fraud be detected, but that in a short time the facility of
+ that detection would act as a deterrent for the future. [This was
+ precisely the experience of Sir W. Herschel.--F.G.] In the majority of
+ cases, the mere question would be, Is the man A the same person as B,
+ or is he not? and of that question the finger marks would give
+ unerring proof. For example, to take the simplest case, A is sued for
+ possession of some land, the title of which he is stated to have
+ parted with to another for a consideration. The document and the
+ Registration Book both bear the imprint of the index finger of the
+ right hand of A. A repudiates, and a comparison shows that whereas
+ the finger pattern of A is a whorl, the imprint on the document is a
+ loop; consequently A did not execute it.
+
+ "In the identification of Government pensioners the finger print
+ method would be very valuable. At one period, I had the payment of
+ many hundreds of military pensioners. Personation was most difficult
+ to detect in persons coming from a distance, who had no local
+ acquaintances, and more especially where the claimants were women. The
+ marks of identification noted in the pension roll were usually
+ variations of:--"Hair black--Eyes brown--Complexion wheat
+ colour--Marks of tattooing on fore-arm"--terms which are equally
+ appropriate to a large number of the pensioners. The description was
+ supplemented in some instances, where the pensioner had some
+ distinguishing mark or scar, but such cases are considerably rarer
+ than might be supposed, and in women the marks are not infrequently in
+ such a position as to practically preclude comparison. Here also the
+ imprint of one or more finger prints on the pension certificate, would
+ be sufficient to settle any doubt as to identity.
+
+ "As a large number of persons pass through the Indian gaols not only
+ while undergoing terms of imprisonment, but in default of payment of a
+ fine, it could not but prove of value were the finger prints of one
+ and all secured. They might assist in identifying persons who have
+ formerly been convicted, of whom the local police have no knowledge,
+ and who bear a name that may be the common property of half a hundred
+ in any small town."
+
+Whatever difficulty may be felt in the identification of Hindoos, is
+experienced in at least an equal degree in that of the Chinese residents
+in our Colonies and Settlements, who to European eyes are still more alike
+than the Hindoos, and in whose names there is still less variety. I have
+already referred (p. 26) to Mr. Tabor, of San Francisco, and his proposal
+in respect to the registration of the Chinese. Remarks showing the need
+of some satisfactory method of identifying them, have reached me from
+various sources. The _British North Borneo Herald_, August 1, 1888, that
+lies before me as I write, alludes to the difficulty of identifying
+coolies, either by photographs or measurements, as likely to become
+important in the early future of that country.
+
+For purposes of registration, the method of printing to be employed, must
+be one that gives little trouble on the one hand, and yields the maximum
+of efficiency for that amount of trouble on the other. Sir W. Herschel
+impressed simultaneously the fore and middle fingers of the right hand. To
+impress simultaneously the fore, middle, and ring-fingers of the right
+hand ought, however, to be better, the trouble being no greater, while
+three prints are obviously more effective than two, especially for an
+off-hand comparison. Moreover, the patterns on the ring-finger are much
+more variable than those on the middle finger. Much as rolled impressions
+are to be preferred for minute and exhaustive comparisons, they would
+probably be inconvenient for purposes of registration or attestation. Each
+finger has to be rolled separately, and each separate rolling takes more
+time than a dab of all the fingers of one hand simultaneously. Now a
+dabbed impression of even two fingers is more useful for registration
+purposes than the rolled impression of one; much more is a dabbed
+impression of three, especially when the third is the variable
+ring-finger. Again, in a simultaneous impression, there is no doubt as to
+the sequence of the finger prints being correct, but there may be some
+occasional bungling when the fingers are printed separately.
+
+ * * * * *
+
+For most criminal investigations, and for some other purposes also, the
+question is not the simple one just considered, namely, "Is A the same
+person, or a different person from B?" but the much more difficult problem
+of "Who is this unknown person X? Is his name contained in such and such a
+register?" We will now consider how this question may be answered.
+
+Registers of criminals are kept in all civilised countries, but in France
+they are indexed according to the method of M. Alphonse Bertillon, which
+admits of an effective search being made through a large collection. We
+shall see how much the differentiating power of the French or of any other
+system of indexing might be increased by including finger prints in the
+register.
+
+M. Bertillon has described his system in three pamphlets:--
+
+ (1) _Une application pratique de l'anthropometrie_, Extrait des
+ Annales de Demographie Interne. Paris 1881. (2) _Les signalements
+ anthropometriques_, Conference faite au Congres Penitentiare
+ International de Rome, Nov. 22, 1885. (3) _Sur le fonctionnement du
+ service des signalements_. All the above are published by Masson, 120
+ Boulevard St. Germain, Paris. To these must be added a very
+ interesting but anonymous pamphlet, based on official documents, and
+ which I have reason to know is authorised by M. Bertillon, namely, (4)
+ _L'anthropometrie Judiciare en Paris, en 1889_: G. Stenheil, 2 Rue
+ Casimir-Delavigne, Paris.
+
+ Besides these a substantial volume is forthcoming, which may give a
+ satisfactory solution to some present uncertainties.
+
+The scale on which the service is carried on, is very large. It was begun
+in 1883, and by the end of 1887 no less than 60,000 sets of measures were
+in hand, but thus far only about one half of the persons arrested in Paris
+were measured, owing to the insufficiency of the staff. Arrangements were
+then made for its further extension. There are from 100 to 150 prisoners
+sentenced each day by the Courts of Law in Paris to more than a few days'
+imprisonment, and every one of these is sent to the Depot for twenty-four
+hours. While there, they are now submitted to _Bertillonage_, a newly
+coined word that has already come into use. This is done in the forenoon,
+by three operators and three clerks; six officials in all. About half of
+the prisoners are old offenders, of whom a considerable proportion give
+their names correctly, as is rapidly verified by an alphabetically
+arranged catalogue of cards, each of which contains front and profile
+photographs, and measurements. The remainder are examined strictly; their
+bodily marks are recorded according to a terse system of a few letters,
+and they are variously measured. Each person occupies seven or eight
+minutes. They are then photographed. From sixty to seventy-five prisoners
+go through this complete process every forenoon. In the afternoon the
+officials are engaged in making numerous copies of each set of records,
+one of which is sent to Lyon, and another to Marseille, where there are
+similar establishments. They also classify the copies of records that are
+received from those towns and elsewhere in France, of which from seventy
+to one hundred arrive daily. Lastly, they search the Registers for
+duplicate sets of measures of those, whether in Paris or in the provinces,
+who were suspected of having given false names. The entire staff consists
+of ten persons. It is difficult to rightly interpret the figures given in
+the pamphlet (4) at pp. 22-24, as they appear to disagree, but as I
+understand them, 562 prisoners who gave false names in the year 1890 were
+recognised by _Bertillonage_, and only four other persons were otherwise
+discovered to have been convicted previously, who had escaped recognition
+by its means.
+
+I had the pleasure of seeing the system in operation in Paris a few years
+ago, and was greatly impressed by the deftness of the measuring, and with
+the swiftness and success with which the assistants searched for the cards
+containing entries similar to the measures of the prisoner then under
+examination.
+
+It is stated in the _Signalements_ (p. 12) that the basis of the
+classification are the four measurements (1) Head-length, (2)
+Head-breadth, (3) Middle-finger-length, (4) Foot-length, their constancy
+during adult life nearly always [as stated] holding good. Each of these
+four elements severally is considered as belonging to one or other of
+three equally numerous classes--small, medium, and large; consequently
+there are 3{4} or 81 principal headings, under some one of which the card
+of each prisoner is in the first instance sorted. Each of these primary
+headings is successively subdivided, on the same general principle of a
+three-fold classification, according to other measures that are more or
+less subject to uncertainties, namely, the height, the span, the cubit,
+the length and breadth of the ear, and the height of the bust. The
+eye-colour alone is subjected to seven divisions. The general result is
+(pp. 19, 22) that a total of twelve measures are employed, of which eleven
+are classed on the three-fold principle, and one on the seven-fold, giving
+a final result of 3{11} x 7, or more than a million possible combinations.
+M. Bertillon considers it by no means necessary to stop here, but in his
+chapter (p. 22) on the "Infinite Extension of the Classification," claims
+that the method may be indefinitely extended.
+
+The success of the system is considered by many experts to be fully
+proved, notwithstanding many apparent objections, one of which is the
+difficulty due to transitional cases: a belief in its success has
+certainly obtained a firm hold upon the popular imagination in France. Its
+general acceptance elsewhere seems to have been delayed in part by a
+theoretical error in the published calculations of its efficiency: the
+measures of the limbs which are undoubtedly correlated being treated as
+independent, and in part by the absence of a sufficiently detailed account
+of the practical difficulties experienced in its employment. Thus in the
+_Application pratique_, p. 9: "We are embarrassed what to choose, the
+number of human measures which vary independently of each other being
+considerable." In the _Signalements_, p. 19: "It has been shown" (by
+assuming this independent variability) "that by seven measurements, 60,000
+photographs can be separated into batches of less than ten in each." (By
+the way, even on that assumption, the result is somewhat exaggerated, the
+figures having been arrived at by successively taking the higher of the
+two nearest round values.) In short, the general tone of these two memoirs
+is one of enthusiastic belief in the method, based almost wholly, so far
+as is there shown, on questionable _theoretic_ grounds of efficiency.
+
+To learn how far correlation interferes with the regularity of
+distribution, causing more entries to be made under some index-heads than
+others, as was the case with finger prints, I have classified on the
+Bertillon system, 500 sets of measures taken at my laboratory. It was not
+practicable to take more than three of the four primary measures, namely,
+the head-length, its breadth, and the middle-finger-length. The other
+measure, that of foot-length, is not made at my laboratory, as it would
+require the shoes to be taken off, which is inconvenient since persons of
+all ranks and both sexes are measured there; but this matters little for
+the purpose immediately in view. It should, however, be noted that the
+head-length and head-breadth have especial importance, being only slightly
+correlated, either together or with any other dimension of the body. Many
+a small man has a head that is large in one or both directions, while a
+small man rarely has a large foot, finger, or cubit, and conversely with
+respect to large men.
+
+The following set of five measures of each of the 500 persons were then
+tabulated: (1) head-length; (2) head-breadth; (3) span; (4) body-height,
+that is the height of the top of the head from the seat on which the
+person sits; (5) middle-finger-length. The measurements were to the
+nearest tenth of an inch, but in cases of doubt, half-tenths were recorded
+in (1), (2), and (5). With this moderate minuteness of measurement, it was
+impossible so to divide the measures as to give better results than the
+following, which show that the numbers in the three classes are not as
+equal as desirable. But they nevertheless enable us to arrive at an
+approximate idea of the irregular character of the distribution.
+
+TABLE XVI.
+
+ +-----------------------------------------------------------------------+
+ | | Medium |Nos. in the three classes respectively.|
+ | Dimensions | measures in |---------------------------------------|
+ | measured. | inches and | - | 0 | + | Total. |
+ | | tenths. | below. | medium. | above. | |
+ |----------------|--------------|--------|---------|---------|----------|
+ |1. Head-length | 7.5 to 7.7 | 101 | 191 | 208 | 500 |
+ |2. Head-breadth | 6.0 " 6.1 | 173 | 201 | 126 | 500 |
+ |3. Span | 68.0 " 70.5 | 137 | 165 | 198 | 500 |
+ |4. Body-height | 35.0 " 36.0 | 139 | 168 | 193 | 500 |
+ |5. Middle-finger| 4.5 " 4.6 | 180 | 176 | 144 | 500 |
+ +-----------------------------------------------------------------------+
+
+The distribution of the measures is shown in Table XVII.
+
+TABLE XVII.
+
+_Distribution of 500 sets of measures into classes. Each set consists of
+five elements; each element is classed as + or above medium class; M, or
+mediocre; -, or below medium class._
+
+(Total number of classes is 3{5} = 243.)
+
+ +----------------------------------------------------------------+
+ | +---- 3 Span. | |
+ | | | |
+ | | +--4 Body- | 1 Head-length, 2 Head-breadth. |
+ | | | height.| |
+ | | | | |
+ | | | 5 Middle-|-----------------------------------------------|
+ | | | | finger.| 1 2 1 2 1 2 | 1 2 1 2 1 2 | 1 2 1 2 1 2 |
+ | | | | |---------------|---------------|---------------|
+ | | | | | - - - M - + | M - M M M + | + - + M + + |
+ |----------------|---------------|---------------|---------------|
+ | - - - | 14 7 4 | 14 11 5 | 3 3 2 |
+ | M | - 2 - | 2 4 1 | - 2 4 |
+ | + | - - - | 1 - - | - - - |
+ | | | | |
+ | - M - | 5 2 2 | 7 4 2 | 1 4 3 |
+ | M | - 2 - | 3 1 3 | 2 3 - |
+ | + | - - - | - - - | - - 2 |
+ | | | | |
+ | - + - | 2 - - | 1 1 1 | - - 1 |
+ | M | - 2 - | - - - | - 1 1 |
+ | + | - - - | 1 - - | - 1 - |
+ |----------------|---------------|---------------|---------------|
+ | M - - | 4 - 1 | 3 4 3 | 1 2 2 |
+ | M | 3 2 - | 3 2 3 | 2 4 - |
+ | + | - - - | - 1 2 | - 1 - |
+ | | | | |
+ | M M - | 1 3 1 | 4 3 2 | 4 4 3 |
+ | M | 5 3 - | 7 5 2 | 2 6 5 |
+ | + | 2 1 1 | 1 1 - | 1 4 2 |
+ | | | | |
+ | M + - | 2 1 1 | 5 2 - | - 2 2 |
+ | M | 2 2 - | 3 3 1 | 1 6 7 |
+ | + | - - 1 | 2 - - | 3 2 2 |
+ |----------------|---------------|---------------|---------------|
+ | + - - | - - 1 | - 1 - | - - - |
+ | M | 1 - - | 1 2 - | 1 3 - |
+ | + | 1 2 - | 1 1 - | - - 2 |
+ | | | | |
+ | + M - | 1 - 1 | 3 2 - | - - 2 |
+ | M | 2 - 1 | 1 4 - | 3 2 4 |
+ | + | 2 1 - | 2 4 1 | 4 6 3 |
+ | | | | |
+ | + + - | 1 2 - | 1 - 1 | 1 2 2 |
+ | M | - 1 - | 5 10 3 | 3 8 9 |
+ | + | 2 2 2 | 11 10 3 | 9 24 19 |
+ +----------------------------------------------------------------+
+
+The frequency with which 1, 2, 3, 4, etc., sets were found to fall under
+the same index-heading, is shown in Table XVIII.
+
+TABLE XVIII.
+
+ +----------------------------------------------------+
+ | No. of sets | | |
+ | under same | Frequency of its | No. of entries. |
+ | index-heading.| occurrence. | |
+ |---------------|------------------|-----------------|
+ | 0 | 83 | 0 |
+ | 1 | 47 | 47 |
+ | 2 | 47 | 94 |
+ | 3 | 25 | 75 |
+ | 4 | 16 | 64 |
+ | 5 | 7 | 35 |
+ | 6 | 3 | 18 |
+ | 7 | 4 | 28 |
+ | 8 | 1 | 8 |
+ | 9 | 2 | 18 |
+ | 10 | 2 | 20 |
+ | 11 | 2 | 22 |
+ | 14 | 2 | 28 |
+ | 19 | 1 | 19 |
+ | 24 | 1 | 24 |
+ |----------------------------------------------------|
+ | Total entries 500 |
+ +----------------------------------------------------+
+
+No example was found of 83, say of one-third, of the 243 possible
+combinations. In one case no less than 24 sets fell under the same head;
+in another case 19 did so, and there were two cases in which 14, 11, and
+10 severally did the same. Thus, out of 500 sets (see the five bottom
+lines in the last column of the above table) no less than 113 sets fell
+into four classes, each of which included from 10 to 24 entries.
+
+The 24 sets whose Index-number is + M, + + + admit of being easily
+subdivided and rapidly sorted by an expert, into smaller groups, paying
+regard to considerable differences only, in the head-length and
+head-breadth. After doing this, two comparatively large groups remain,
+with five cases in each, which require further analysis. They are as
+follow, the height and eye-colour being added in each case, and brackets
+being so placed as to indicate measures that do not differ to a sufficient
+amount to be surely distinguished. No two sets are alike throughout, some
+difference of considerable magnitude always occurring to distinguish them.
+Nos. 2 and 3 come closest together, and are distinguished by eye-colour
+alone.
+
+TABLE XIX.
+
+ Five cases of Head-length 8.0, and Head-breadth 6.1.
+
+ Span. Body. Finger. Height. Eye-colour.
+
+ 1. { 72.4 38.0 4.8 { 71.2 { br. grey
+ 2. { 72.6 { 37.0 { 4.7 { 71.4 { br. grey
+ 3. { 72.7 { 36.7 { 4.7 { 71.4 blue
+ 4. 73.9 36.4 5.0 70.7 brown
+ 5. 75.3 37.9 4.8 73.4 blue
+
+ Five cases of Head-length 7.8, and Head-breadth 6.0.
+
+ 6. 70.8 37.8 { 4.7 { 70.0 brown
+ 7. { 71.9 36.2 { 4.7 { 69.3 blue
+ 8. { 72.4 { 37.2 { 4.7 { 68.4 brown
+ 9. 74.8 { 37.8 5.0 73.1 blue
+ 10. 79.9 { 37.3 5.3 75.6 blue grey
+
+This is satisfactory. It shows that each one of the 500 sets may be
+distinguished from all the others by means of only seven elements; for if
+it is possible so to subdivide twenty-four entries that come under one
+index-heading, we may assume that we could do so in the other cases where
+the entries were fewer. The other measures that I possess--strength of
+grasp and breathing capacity--are closely correlated with stature and
+bulk, while eyesight and reaction-time are uncorrelated, but the latter
+are hardly suited to test the further application of the Bertillon method.
+
+It would appear, from these and other data, that a purely anthropometric
+classification, irrespective of bodily marks and photographs, would enable
+an expert to deal with registers of considerable size.
+
+Bearing in mind that mediocrities differ less from one another than
+members of either of the extreme classes, and would therefore be more
+difficult to distinguish, it seems probable that with comparatively few
+exceptions, _at least_ two thousand adults of the same sex might be
+individualised, merely by means of twelve careful measures, on the
+Bertillon system, making reasonable allowances for that small change of
+proportions that occurs after the lapse of a few years, and for
+inaccuracies of measurement. This estimate may be far below the truth, but
+more cannot, I think, be safely inferred from the above very limited
+experiment.
+
+The system of registration adopted in the American army for tracing
+suspected deserters, was described in a memoir contributed to the
+"International Congress of Demography," held in London in 1891. The memoir
+has so far been only published in the _Abstracts of Papers_, p. 233 (Eyre
+and Spottiswoode). Its phraseology is unfortunately so curt as sometimes
+to be difficult to understand; it runs as follows:--
+
+ Personal identity as determined by scars and other body marks by
+ Colonel Charles R. Greenleaf and Major Charles Smart, Medical
+ Department, U.S. Army.
+
+ Desertions from United States army believed to greatly exceed
+ deserters, owing to repeaters.
+
+ Detection of repeaters possible if all body marks of all recruits
+ recorded, all deserters noted, and all recruits compared with previous
+ deserters.
+
+ In like manner men discharged for cause excluded from re-entry.
+
+ Bertillon's anthropometric method insufficient before courts-martial,
+ because possible inaccuracies in measurement, and because of allowable
+ errors.
+
+ But identity acknowledged following coincident indelible marks, when
+ height, age, and hair fairly correspond.
+
+ That is, Bertillon's collateral evidence is practically primary
+ evidence for such purposes.
+
+ There is used for each man an outline figure card giving anterior and
+ posterior surfaces, divided by dotted lines into regions.
+
+ These, showing each permanent mark, are filed alphabetically at the
+ Surgeon-General's office, War Department.
+
+ As a man goes out for cause, or deserts, his card is placed in a
+ separate file.
+
+ The cards of recruits are compared with the last-mentioned file.
+
+ To make this comparison, a register in two volumes is opened, one for
+ light-eyed and one for dark-eyed men. Each is subdivided into a fair
+ number of pages, according to height of entrants, and each page is
+ ruled in columns for body regions. Tattooed and non-tattooed men of
+ similar height and eyes are entered on opposite pages. Recruits
+ without tattoos are not compared with deserters with tattoos; but
+ recruits with tattoos are compared with both classes.
+
+ On the register S T B M, etc., are used as abbreviations for scar,
+ tattoo, birth-mark, mole, etc.
+
+ One inch each side of recorded height allowed for variation or
+ defective measurement.
+
+ When probability of identity appears, the original card is used for
+ comparison.
+
+ Owing to obstacles in inaugurating new system, its practical working
+ began with 1891, and, to include May 1891 [= 5 months, F.G.], out of
+ sixty-two cases of suspected fraud sixty-one proved real.
+
+There was some interesting discussion, both upon this memoir and on a
+verbal communication concerning the French method, that had been made by
+M. Jacques Bertillon the statistician, who is a brother of its originator.
+It appeared that there was room for doubt whether the anthropometric
+method had received a fair trial in America, the measurements being made
+by persons not specially trained, whereas in France the establishments,
+though small, are thoroughly efficient.
+
+There are almost always moles or birth-marks, serving for identification,
+on the body of every one, and a record of these is, as already noted, an
+important though subsidiary part of the Bertillon system. Body-marks are
+noted in the English registers of criminals, and it is curious how large a
+proportion of these men are tattooed and scarred. How far the body-marks
+admit of being usefully charted on the American plan, it is difficult to
+say, the success of the method being largely dependent on the care with
+which they are recorded. The number of persons hitherto dealt with on the
+American plan appears not to be very large. As observations of this class
+require the person to be undressed, they are unsuitable for popular
+purposes of identification, but the marks have the merit of serving to
+identify at all ages, which the measurements of the limbs have not.
+
+It seems strange that no register of this kind, so far as I know, takes
+account of the teeth. If a man, on being first registered, is deficient in
+certain teeth, they are sure to be absent when he is examined on a future
+occasion. He may, and probably will in the meantime, have lost others, but
+the fact of his being without specified teeth on the first occasion,
+excludes the possibility of his being afterwards mistaken for a man who
+still possesses them.
+
+We will now separately summarise the results arrived at, in respect to the
+two processes that may both be needed in order to effect an
+identification.
+
+First, as regards _search in an Index_.--Some sets of measures will give
+trouble, but the greater proportion can apparently be catalogued with so
+much certainty, that if a second set of measures of any individual be
+afterwards taken, no tedious search will be needed to hunt out the former
+set. Including the bodily marks and photographs, let us rate the Bertillon
+method as able to cope with a register of 20,000 adults of the same sex,
+with a small and definable, but as yet unknown, average dose of
+difficulty, which we will call _x_.
+
+A catalogue of 500 sets of finger prints easily fulfils the same
+conditions. I could lay a fair claim to much more, but am content with
+this. Now the finger patterns have been shown to be so independent of
+other conditions that they cannot be notably, if at all, correlated with
+the bodily measurements or with any other feature, not the slightest
+trace of any relation between them having yet been found, as will be shown
+at p. 186, and more fully in Chapter XII. For instance, it would be
+totally impossible to fail to distinguish between the finger prints of
+twins, who in other respects appeared exactly alike. Finger prints may
+therefore be treated without the fear of any sensible error, as varying
+quite independently of the measures and records in the Bertillon system.
+Their inclusion would consequently increase its power fully five-hundred
+fold. Suppose one moderate dose of difficulty, _x_, is enough for dealing
+with the measurements, etc., of 20,000 adult persons of the same sex by
+the Bertillon method, and a similar dose of difficulty with the finger
+prints of 500 persons, then two such doses could deal with a register of
+20,000 x 500, or 10,000,000.
+
+We now proceed to consider the second and final process, namely, that of
+identification by _Comparison_. When the data concerning a suspected
+person are discovered to bear a general likeness to one of those already
+on the register, and a minute comparison shows their finger prints to
+agree in all or nearly all particulars, the evidence thereby afforded that
+they were made by the same person, far transcends in trustworthiness any
+other evidence that can ordinarily be obtained, and vastly exceeds all
+that can be derived from any number of ordinary anthropometric data. _By
+itself it is amply sufficient to convict._ _Bertillonage_ can rarely
+supply more than grounds for very strong suspicion: the method of finger
+prints affords certainty. It is easy, however, to understand that so long
+as the peculiarities of finger prints are not generally understood, a
+juryman would be cautious in accepting their evidence, but it is to be
+hoped that attention will now gradually become drawn to their marvellous
+virtues, and that after their value shall have been established in a few
+conspicuous cases, it will come to be popularly recognised.
+
+Let us not forget two great and peculiar merits of finger prints; they are
+self-signatures, free from all possibility of faults in observation or of
+clerical error; and they apply throughout life.
+
+An abstract of the remarks made by M. Herbette, Director of the
+Penitentiary Department of the Ministere de l'Interieur, France, at the
+International Penitentiary Congress at Rome, after the communication by M.
+Alphonse Bertillon had been read, may fitly follow.
+
+ "Proceeding to a more extended view of the subject and praising the
+ successful efforts of M. Bertillon, M. Herbette pointed out how a
+ verification of the physical personality, and of the identity of
+ people of adult age, would fulfil requirements of modern society in an
+ indisputable manner under very varied conditions.
+
+ "If it were a question, for instance, of giving to the inhabitants of
+ a country, to the soldiers of an army, or to travellers proceeding to
+ distant lands, notices or personal cards as recognisable signs,
+ enabling them always to prove who they are; if it were a question of
+ completing the obligatory records of civil life by perfectly sure
+ indications, such as would prevent all error, or substitution of
+ persons; if it were a question of recording the distinctive marks of
+ an individual in documents, titles or contracts, where his identity
+ requires to be established for his own interest, for that of third
+ parties, or for that of the State,--there the anthropometric system
+ of identification would find place.
+
+ "Should it be a question of a life certificate, of a life assurance,
+ or of a proof of death, or should it be required to certify the
+ identity of a person who was insane, severely wounded, or of a dead
+ body that had been partly destroyed, or so disfigured as to be hardly
+ recognisable from a sudden or violent death due to crime, accident,
+ shipwreck, or battle--how great would be the advantage of being able
+ to trace these characters, unchangeable as they are in each
+ individual, infinitely variable as between one individual and another,
+ indelible, at least in part, even in death.
+
+ "There is still more cause to be interested in this subject when it is
+ a question of identifying persons who are living at a great distance,
+ and after the lapse of a considerable time, when the physiognomy, the
+ features, and the physical habits may have changed from natural or
+ artificial causes, and to be able to identify them without taking a
+ journey and without cost, by the simple exchange of a few lines or
+ figures that may be sent from one country or continent to another, so
+ as to give information in America as to who any particular man is, who
+ has just arrived from France, and to certify whether a certain
+ traveller found in Rome is the same person who was measured in
+ Stockholm ten years before.
+
+ "In one word, to fix the human personality, to give to each human
+ being an identity, an individuality that can be depended upon with
+ certainty, lasting, unchangeable, always recognisable and easily
+ adduced, this appears to be in the largest sense the aim of the new
+ method.
+
+ "Consequently, it may be said that the extent of the problem, as well
+ as the importance of its solution, far exceeds the limits of
+ penitentiary work and the interest, which is however by no means
+ inconsiderable, that penal action has excited amongst various nations.
+ These are the motives for giving to the labours of M. Bertillon and to
+ their practical utilisation the publicity they merit."
+
+These full and clear remarks seem even more applicable to the method of
+finger prints than to that of anthropometry.
+
+
+
+
+CHAPTER XI
+
+HEREDITY
+
+
+Some of those who have written on finger marks affirm that they are
+transmissible by descent, others assert the direct contrary, but no
+inquiry hitherto appears to justify a definite conclusion.
+
+Chapter VIII. shows a close correlation to exist between the patterns on
+the several fingers of the same person. Hence we are justified in assuming
+that the patterns are partly dependent on constitutional causes, in which
+case it would indeed be strange if the general law of heredity failed in
+this particular case.
+
+After examining many prints, the frequency with which some peculiar
+pattern was found to characterise members of the same family convinced me
+of the reality of an hereditary tendency. The question was how to submit
+the belief to numerical tests; particular kinships had to be selected, and
+methods of discussion devised.
+
+It must here be borne in mind that "Heredity" implies more than its
+original meaning of a relationship between parent and child. It includes
+that which connects children of the same parents, and which I have shown
+(_Natural Inheritance_) to be just twice as close in the case of stature
+as that which connects a child and either of its two parents. Moreover,
+the closeness of the fraternal and the filial relations are to a great
+extent interdependent, for in any population whose faculties remain
+_statistically_ the same during successive generations, it has been shown
+that a simple algebraical equation must exist, that connects together the
+three elements of Filial Relation, Fraternal Relation, and Regression, by
+which a knowledge of any two of them determines the value of the third. So
+far as Regression may be treated as being constant in value, the Filial
+and the Fraternal relations become reciprocally connected. It is not
+possible briefly to give an adequate explanation of all this now, or to
+show how strictly observations were found to confirm the theory; this has
+been fully done in _Natural Inheritance_, and the conclusions will here be
+assumed.
+
+The fraternal relation, besides disclosing more readily than other
+kinships the existence or non-existence of heredity, is at the same time
+more convenient, because it is easier to obtain examples of brothers and
+sisters alone, than with the addition of their father and mother. The
+resemblance between those who are twins is also an especially significant
+branch of the fraternal relationship. The word "fraternities" will be used
+to include the children of both sexes who are born of the same parents; it
+being impossible to name the familiar kinship in question either in
+English, French, Latin, or Greek, without circumlocution or using an
+incorrect word, thus affording a striking example of the way in which
+abstract thought outruns language, and its expression is hampered by the
+inadequacy of language. In this dilemma I prefer to fall upon the second
+horn, that of incorrectness of phraseology, subject to the foregoing
+explanation and definition.
+
+The first preliminary experiments were made with the help of the
+Arch-Loop-Whorl classification, on the same principle as that already
+described and utilised in Chapter VIII., with the following addition. Each
+of the two members of any couplet of fingers has a distinctive name--for
+instance, the couplet may consist of a finger and a thumb: or again, if it
+should consist of two fore-fingers, one will be a right fore-finger and
+the other a left one, but the two brothers in a couplet of brothers rank
+equally as such. The plan was therefore adopted of "ear-marking" the
+prints of the first of the two brothers that happened to come to hand,
+with an A, and that of the second brother with a B; and so reducing the
+questions to the shape:--How often does the pattern on the finger of a B
+brother agree with that on the corresponding finger of an A brother? How
+often would it occur between two persons who had no family likeness? How
+often would it correspond if the kinship between A and B were as close as
+it is possible to conceive? Or transposing the questions, and using the
+same words as in Chapter VIII., what is the relative frequency of (1)
+Random occurrences, (2) Observed occurrences, (3) Utmost possibilities?
+It was shown in that chapter how to find the value of (2) upon a
+centesimal scale in which "Randoms" ranked as 0 deg. and "Utmost
+possibilities" as 100 deg.
+
+The method there used of calculating the frequency of the "Random" events
+will be accepted without hesitation by all who are acquainted with the
+theory and the practice of problems of probability. Still, it is as well
+to occasionally submit calculation to test. The following example was sent
+to me for that purpose by a friend who, not being mathematically minded,
+had demurred somewhat to the possibility of utilising the calculated
+"Randoms."
+
+The prints of 101 (by mistake for 100) couplets of prints of the right
+fore-fingers of school children were taken by him from a large collection,
+the two members, A and B, being picked out at random and formed into a
+couplet. It was found that among the A children there were 22 arches, 50
+loops, and 29 whorls, and among the B children 25, 34, and 42
+respectively, as is shown by the _italic_ numerals in the last column, and
+again in the bottom row of Table XX. The remainder of the table shows the
+number of times in which an arch, loop, or whorl of an A child was
+associated with an arch, loop, or whorl of a B child.
+
+TABLE XX.
+
+_Observed Random Couplets._
+
+ +----------------------------------------------------+
+ | | A children. | Totals in |
+ | B children. |------------------------| B children. |
+ | | Arches.| Loops.|Whorls.| |
+ |-------------|--------|-------|-------|-------------|
+ | Arches | 5 | 12 | 8 | _25_ |
+ | Loops | 8 | 18 | 8 | _34_ |
+ | Whorls | 9 | 20 | 13 | _42_ |
+ |-------------|--------|-------|-------|-------------|
+ |Totals in A} | | | | |
+ | children } | _22_ | _50_ | _29_ | 101 |
+ +----------------------------------------------------+
+
+TABLE XXI.
+
+_Calculated Random Couplets._
+
+ +----------------------------------------------------+
+ | | A children. | Totals in |
+ | B children. |------------------------| B children. |
+ | | Arches.| Loops.|Whorls.| |
+ |-------------|--------|-------|-------|-------------|
+ | Arches | 5.00 | 12.50 | 7.25 | _25_ |
+ | Loops | 6.80 | 17.00 | 9.86 | _34_ |
+ | Whorls | 8.40 | 21.00 | 12.18 | _42_ |
+ |-------------|--------|-------|-------|-------------|
+ |Totals in A} | | | | |
+ | children } | _22_ | _50_ | _29_ | 101 |
+ +----------------------------------------------------+
+
+The question, then, was how far calculations from the above data would
+correspond with the contents of Table XX. The answer is that it does so
+admirably. Multiply each of the italicised A totals into each of the
+italicised B totals, and after dividing each result by 101, enter it in
+the square at which the column that has the A total at its base, is
+intersected by the row that has the B total at its side. We thus obtain
+Table XXI.
+
+We will now discuss in order the following relationships: the Fraternal,
+first in the ordinary sense, and then in the special case of twins of the
+same set; Filial, in the special case in which both parents have the same
+particular pattern on the same finger; lastly, the relative influence of
+the father and mother in transmitting their patterns.
+
+_Fraternal relationship._--In 105 fraternities the _observed_ figures were
+as in Table XXII.:--
+
+TABLE XXII.
+
+_Observed Fraternal Couplets._
+
+ +----------------------------------------------------+
+ | | A children. | Totals in |
+ | B children. |----------------------| B children. |
+ | |Arches.|Loops.|Whorls.| |
+ |--------------|-------|------|-------|--------------|
+ |Arches | 5 | 12 | 2 | _19_ |
+ | |-------+------| | |
+ |Loops | 4 | 42 | 15 | _61_ |
+ | |-------|------|-------| |
+ |Whorls | 1 | 14 | 10 | _25_ |
+ |--------------|-------+------+-------|--------------|
+ |Totals in A } | | | | |
+ | children } | _10_ | _68_ | _27_ | 105 |
+ +----------------------------------------------------+
+
+The squares that run diagonally from the top at the left, to the bottom at
+the right, contain the double events, and it is with these that we are
+now concerned. Are the entries in those squares larger or not than the
+randoms, calculated as above, viz. the values of 10 x 19, 68 x 61, 27 x
+25, all divided by 105? The calculated Randoms are shown in the first line
+of Table XXIII., the third line gives the greatest feasible number of
+correspondences which would occur if the kinship were as close as
+possible, subject to the reservation explained in p. 127. As there shown,
+the _lower_ of the A and B values is taken in each case, for Arches,
+Loops, and Whorls respectively.
+
+TABLE XXIII.
+
+ +----------------------------------------------+
+ | | A and B both being |
+ | |----------------------------|
+ | | Arches. | Loops. | Whorls. |
+ |-----------------|---------|--------|---------|
+ | Random | 1.7 | 37.6 | 6.2 |
+ | Observed | 5.0 | 42.0 | 10.0 |
+ | Utmost feasible | 10.0 | 61.0 | 25.0 |
+ +----------------------------------------------+
+
+In every instance, the Observed values are seen to exceed the Random.
+
+Many other cases of this description were calculated, all yielding the
+same general result, but these results are not as satisfactory as can be
+wished, owing to their dilution by inappropriate cases, the A. L. W.
+system being somewhat artificial.
+
+
+[Illustration: PLATE 16.
+
+FIG. 24. The "C" set of standard patterns, for prints of the Right Hand.]
+
+
+With the view of obtaining a more satisfactory result the patterns were
+subdivided under fifty-three heads, and an experiment was made with the
+fore, middle, and ring-fingers of 150 fraternal couplets (300
+individuals and 900 digits) by Mr. F. Howard Collins, who kindly undertook
+the considerable labour of indexing and tabulating them.
+
+The provisional list of standard patterns published in the _Phil. Trans._
+was not appropriate for this purpose. It related chiefly to thumbs, and
+consequently omitted the tented arch; it also referred to the left hand,
+but in the following tabulations the right hand has been used; and its
+numbering is rather inconvenient. The present set of fifty-three patterns
+has faults, and cannot be considered in any way as final, but it was
+suitable for our purposes and may be convenient to others; as Mr. Collins
+worked wholly by it, it may be distinguished as the "C. set." The banded
+patterns, 24-31, are very rarely found on the fingers, but being common on
+the thumb, were retained, on the chance of our requiring the introduction
+of thumb patterns into the tabulations. The numerals refer to the patterns
+as seen in impressions of the _right hand_ only. [They would be equally
+true for the patterns as seen on the _fingers themselves_ of the left
+hand.] For impressions of the left hand the numerals up to 7 inclusive
+would be the same, but those of all the rest would be changed. These are
+arranged in couplets, the one member of the couplet being a reversed
+picture of the other, those in each couplet being distinguished by
+severally bearing an odd and an even number. Therefore, in impressions of
+the left hand, 8 would have to be changed into 9, and 9 into 8; 10 into
+11, and 11 into 10; and so on, up to the end, viz. 52 and 53. The numeral
+54 was used to express nondescript patterns.
+
+The finger prints had to be gone through repeatedly, some weeks elapsing
+between the inspections, and under conditions which excluded the
+possibility of unconscious bias; a subject of frequent communication
+between Mr. Collins and myself. Living at a distance apart, it was not
+easy at the time they were made, to bring our respective interpretations
+of transitional and of some of the other patterns, especially the invaded
+loops, into strict accordance, so I prefer to keep his work, in which I
+have perfect confidence, independent from my own. Whenever a fraternity
+consisted of more than two members, they were divided, according to a
+prearranged system, into as many couplets as there were individuals. Thus,
+while a fraternity of three individuals furnished all of its three
+possible varieties of couplets, (1, 2), (1, 3), (2, 3), one of four
+individuals was not allowed to furnish more than four of its possible
+couplets, the two italicised ones being omitted, (1, 2), (1, 3), (_1, 4_),
+(_2, 3_), (2, 4), (3, 4), and so on. Without this precaution, a single
+very large family might exercise a disproportionate and even overwhelming
+statistical influence.
+
+It would be essential to exact working, that the mutual relations of the
+patterns should be taken into account; for example, suppose an arch to be
+found on the fore-finger of one brother and a nascent loop on that of the
+other; then, as these patterns are evidently related, their concurrence
+ought to be interpreted as showing some degree of resemblance. However,
+it was impossible to take cognizance of partial resemblances, the mutual
+relations of the patterns not having, as yet, been determined with
+adequate accuracy.
+
+The completed tabulations occupied three large sheets, one for each of the
+fingers, ruled crossways into fifty-three vertical columns for the A
+brothers, and fifty-three horizontal rows for the B brothers. Thus, if the
+register number of the pattern of A was 10, and that of B was 42, then a
+mark would be put in the square limited by the ninth and tenth horizontal
+lines, and by the forty-first and forty-second vertical ones. The marks
+were scattered sparsely over the sheet. Those in each square were then
+added up, and finally the numbers in each of the rows and in each of the
+columns were severally totalled.
+
+If the number of couplets had been much greater than they are, a test of
+the accuracy with which their patterns had been classed under the
+appropriate heads, would be found in the frequency with which the same
+patterns were registered in the corresponding finger of the A and B
+brothers. The A and B groups are strictly homogeneous, consequently the
+frequency of their patterns in corresponding fingers ought to be alike.
+The success with which this test has been fulfilled in the present case,
+is passably good, its exact degree being shown in the following
+paragraphs, where the numbers of entries under each head are arranged in
+as orderly a manner as the case admits, the smaller of the two numbers
+being the one that stands first, whether it was an A or a B. All instances
+in which there were at least five entries under either A or B, are
+included; the rest being disregarded. The result is as follows:--
+
+ I. Thirteen cases of more or less congruity between the number of A
+ and B entries under the same head:--5-7; 5-7; 5-8; 6-8; 7-10; 8-9;
+ 8-12; 9-12; 10-10; 11-13; 12-16; 14-18; 72-73. (This last refers to
+ loops on the middle finger.)
+
+ II. Six cases of more or less incongruity:--1-7; 6-12; 14-20; 14-22;
+ 22-35; 39-50.
+
+The three Tables, XXIV., XXV., XXVI., contain the results of the
+tabulations and the deductions from them.
+
+TABLE XXIV.
+
+_Comparison of three Fingers of the Right Hand in 150 Fraternal Couplets._
+
+ +------------------------------------------------------------------------+
+ | | Fore-fingers. || Middle fingers. || Ring-fingers. |
+ | |--------------------||--------------------||--------------------|
+ | Index | Down |Along|Double|| Down |Along|Double|| Down |Along|Double|
+ | No. of|columns|lines|events||columns|lines|events||columns|lines|events|
+ |Pattern|-------|-----|------||-------|-----|------||-------|-----|------|
+ | | | | A || | | A || | | A |
+ | | A | B | and || A | B | and || A | B | and |
+ | | | | B || | | B || | | B |
+ |-------|-------|-----|------||-------|-----|------||-------|-----|------|
+ | 1 | 15 | 12 | 4 || 8 | 5 | 2 || 7 | 5 | 1 |
+ | 2 | 3 | 2 | || 3 | 2 | || | | |
+ | 6 | 2 | 2 | 1 || | | || 2 | 4 | |
+ | 7 | | 2 | || 2 | 1 | || 7 | 5 | 1 |
+ | 8 | | | || | | || | 1 | |
+ | 9 | 1 | 7 | || 4 | 1 | 1 || 7 | 1 | |
+ | 12 | 1 | | || 2 | | || | | |
+ | 13 | | | || 2 | 1 | || | | |
+ | 14 | 4 | 3 | || 4 | 4 | 1 || 20 | 14 | 1 |
+ | 15 | 16 | 12 | 3 || 4 | 2 | || 3 | 4 | |
+ | 16 | 2 | 3 | || 2 | 3 | || 10 | 7 | 2 |
+ | 17 | 4 | 3 | || 3 | | || | | |
+ | 18 | | | || 4 | 1 | || 18 | 14 | 6 |
+ | 19 | 3 | 3 | || 2 | 5 | || 1 | | |
+ | 20 | | | || | | || 1 | 3 | 1 |
+ | 21 | | 1 | || | | || | | |
+ | 22 | | 4 | || 1 | 8 | || 1 | 2 | |
+ | 23 | 1 | | || 1 | | || 6 | | |
+ | 27 | 1 | | || | | || | | |
+ | 32 | 1 | | || 1 | 3 | || 4 | 4 | |
+ | 33 | 3 | 1 | 1 || 1 | | || 3 | 3 | 1 |
+ | 34 | 3 | 2 | || 4 | 1 | || | | |
+ | 35 | 2 | 3 | || | 5 | || 9 | 12 | 2 |
+ | 38 | 2 | 1 | || | | || | | |
+ | 39 | 4 | | || 3 | 1 | || | | |
+ | 40 | 13 | 11 | 1 || 14 | 22 | 6 || 9 | 8 | |
+ | 41 | 12 | 8 | || 1 | 3 | || | 1 | |
+ | 42 | 22 | 35 | 5 || 73 | 72 | 35 || 39 | 50 | 16 |
+ | 43 | 10 | 10 | 3 || 4 | 1 | || | 3 | |
+ | 44 | 2 | 1 | || | 2 | || | 2 | |
+ | 45 | 1 | 1 | || | | || | | |
+ | 46 | 8 | 6 | 1 || 3 | 1 | || | 1 | |
+ | 47 | 3 | 4 | || | | || | | |
+ | 48 | 6 | 12 | 1 || 4 | 6 | || 2 | 3 | |
+ | 49 | 1 | 1 | || | | || | | |
+ | 52 | | | || | | || 1 | | |
+ | 53 | | | || | | || | 1 | |
+ +------------------------------------------------------------------------+
+
+TABLE XXV.
+
+_Comparison between Random and Observed Events._
+
+ +-------------------------------------------------------------+
+ | Fore. || Middle. || Ring. |
+ |-------------------||-------------------||-------------------|
+ | Random.| Observed.|| Random.| Observed.|| Random.| Observed.|
+ |--------|----------||--------|----------||--------|----------|
+ | 1.20 | 4 || 0.26 | 2 || 0.23 | 1 |
+ | 0.08 | ... || 0.11 | 1 || 0.05 | ... |
+ | 1.28 | 3 || 0.05 | ... || 0.23 | ... |
+ | 0.08 | ... || 0.07 | ... || 1.87 | 1 |
+ | 0.06 | ... || 0.05 | ... || 0.08 | ... |
+ | 0.95 | 1 || 2.05 | 6 || 0.46 | 2 |
+ | 0.64 | ... || 34.08 | 35 || 1.68 | 6 |
+ | 5.18 | 5 || 0.16 | ... || 0.11 | ... |
+ | 0.67 | 3 || | || 0.06 | 1 |
+ | 0.32 | 1 || | || 0.72 | 2 |
+ | 0.08 | ... || | || 0.48 | ... |
+ | 0.48 | 1 || | || 13.00 | 16 |
+ |--------| || | || | |
+ | All | || | || | |
+ | others.| || | || | |
+ | 0.29 | 2 || 0.28 | 1 || 0.12 | 1 |
+ |--------|----------||--------|----------||--------|----------|
+ | 11.31 | 20 || 37.11 | 45 || 19.09 | 30 |
+ +-------------------------------------------------------------+
+
+TABLE XXVI.
+
+_Centesimal Scale (to nearest whole numbers)._
+
+ +-----------------------------------------------------------------------+
+ |150 fraternal|Random.|Observed.| Utmost |Reduced | Reduced to |
+ | couplets. | | |possibilities.|to lower | upper |
+ | | | | |limit=0. | limit=100. |
+ |-------------|-------|---------|--------------|---------|--------------|
+ | | | | | | Centesimal |
+ | | | | | | scale. |
+ | | | | | |--------------|
+ |Fore-finger | 11.31 | 20 | 115 |0 9 104 |0 deg. 9 deg. 100 deg.|
+ |Middle | 37.11 | 45 | 117 |0 10 80 |0 deg. 10 deg. 100 deg.|
+ |Ring | 19.09 | 31 | 118 |0 12 99 |0 deg. 12 deg. 100 deg.|
+ |-----------------------------------------------------------------------|
+ | Mean |0 deg. 10 deg. 100 deg.|
+ |-----------------------------------------------------------------------|
+ |50 additional| | | | | |
+ | couplets. | | | | | |
+ |-------------| | | | | |
+ |Middle finger| | | | | |
+ |only | 8.2 | 11 | 22 |0 3 14 |0 deg. 21 deg. 100 deg.|
+ |-------------|-------|---------|--------------|---------|--------------|
+ | Loops only, | | | | | |
+ |and on middle| | | | | |
+ | finger only.| | | | | |
+ |-------------| | | | | |
+ |150 couplets | 34.0 | 35 | 72 |0 1 72 |0 deg. 1-1/4 deg. 100 deg.|
+ |50 couplets | 6.4 | 7 | 14 |0 0.6 8 |0 deg. 8 deg. 100 deg.|
+ +-----------------------------------------------------------------------+
+
+Table XXIV. contains all the Observed events, and is to be read thus,
+beginning at the first entry. Pattern No. 1 occurs on the right
+fore-finger fifteen times among the A brothers, and twelve times among the
+B brothers; while in four of these cases both brothers have that same
+pattern.
+
+Table XXV. compares the Random events with the Observed ones. Every case
+in which the calculated expectation is equal to or exceeds 0.05, is
+inserted in detail; the remaining group of petty cases are summed together
+and their totals entered in the bottom line. For fear of misapprehension
+or forgetfulness, one other example of the way in which the Randoms are
+calculated will be given here, taking for the purpose the first entry in
+Table XXIV. Thus, the number of all the different combinations of the 150
+A with the 150 B individuals in the 150 couplets, is 150 x 150. Out of
+these, the number of double events in which pattern No. 1 would appear in
+the same combination, is 15 x 12 = 180. Therefore in 150 trials, the
+double event of pattern No. 1 would appear upon the average, on 180
+divided by 150, or on 1.20 occasions. As a matter of fact, it appeared
+four times. These figures will be found in the first line of Table XXV.;
+the rest of its contents have been calculated in the same way.
+
+Leaving aside the Randoms that exceed 0 but are less than 1, there are
+nineteen cases in which the Random may be compared with the Observed
+values; in all but two of these the Observed are the highest, and in these
+two the Random exceed the Observed by only trifling amounts, namely, 5.18
+Random against 5.00 Observed; 1.87 Random against 1.00 Observed. It is
+impossible, therefore, to doubt from the steady way in which the Observed
+values overtop the Randoms, that there is a greater average likeness in
+the finger marks of two brothers, than in those of two persons taken at
+hazard.
+
+Table XXVI. gives the results of applying the centesimal scale to the
+measurement of the average closeness of fraternal resemblance, in respect
+to finger prints, according to the method and under the reservations
+already explained in page 125. The average value thus assigned to it is a
+little more than 10 deg. The values obtained from the three fingers
+severally, from which that average was derived, are 9 deg., 10 deg., and 12 deg.; they
+agree together better than might have been expected. The value obtained
+from a set of fifty additional couplets of the middle fingers only, of
+fraternals, is wider, being 21 deg. Its inclusion with the rest raises the
+average of all to between 10 and 11.
+
+In the pre-eminently frequent event of loops with an outward slope on the
+middle finger, it is remarkable that the Random cases are nearly equal to
+the Observed ones; they are 34.08 to 35.00. It was to obtain some
+assurance that this equality was not due to statistical accident, that the
+additional set of fifty couplets were tabulated. They tell, however, the
+same tale, viz. 6.4 Randoms to 7.0 Observed. The loops on the fore-fingers
+confirm this, showing 5.18 Randoms to 5.00 Observed; those on the
+ring-finger have the same peculiarity, though in a slighter degree, 13 to
+16: the average of other patterns shows a much greater difference than
+that. I am unable to account for this curious behaviour of the loops,
+which can hardly be due to statistical accident, in the face of so much
+concurrent evidence.
+
+_Twins._--The signs of heredity between brothers and sisters ought to be
+especially apparent between twins of the same sex, who are physiologically
+related in a peculiar degree and are sometimes extraordinarily alike. More
+rarely, they are remarkably dissimilar. The instances of only a moderate
+family resemblance between twins of the same sex are much less frequent
+than between ordinary brothers and sisters, or between twins of opposite
+sex. All this has been discussed in my _Human Faculty_. In order to test
+the truth of the expectation, I procured prints of the fore, middle, and
+ring-fingers of seventeen sets of twins, and compared them, with the
+results shown in Table XXVII.
+
+TABLE XXVII.
+
+17 SETS OF TWINS (A and B).
+
+_Comparison between the patterns on the Fore, Middle, and Ring-fingers
+respectively of the Right hand._
+
+Agreement (=), 19 cases; partial (..), 13 cases; disagreement (x), 19
+cases.
+
+ +----------------------------------------------------------------+
+ | | A B | A B | A B | A B | A B |
+ |----------------------------------------------------------------|
+ |Fore | 42 = 42 | 21 = 21 | 40 = 40 | 6 = 6 | 1 = 1 |
+ |Middle| 42 = 42 | 8 = 8 | 32 x 42 | 15 .. 32 | 42 = 42 |
+ |Ring | 42 = 42 | 8 = 8 | 42 = 42 | 33 = 33 | 40 x 19 |
+ | | | | | | |
+ |Fore | 42 = 42 | 43 x 15 | 1 = 1 | 15 x 34 | 2 .. 42 |
+ |Middle| 42 = 42 | 42 .. 40 | 1 x 40 | 42 = 42 | 42 = 42 |
+ |Ring | 42 .. 46 | 35 = 35 | 40 .. 42 | 14 x 32 | 42 x 14 |
+ | | | | | | |
+ |Fore | 49 .. 14 | 15 x 49 | 15 .. 16 | 1 x 42 | 1 x 15 |
+ |Middle| 42 = 42 | 23 x 14 | 19 x 42 | 42 .. 48 | 32 x 22 |
+ |Ring | 9 .. 32 | 14 .. 16 | 6 .. 18 | 42 x 8 | 18 x 23 |
+ | | | | | | |
+ |Fore | 48 x 33 |(loop) x 9 | | | |
+ |Middle| 42 x 22 | 48 x 22 | | | |
+ |Ring | 14 .. 6 | 9 .. 35 | | | |
+ +----------------------------------------------------------------+
+
+The result is that out of the seventeen sets (=51 couplets), two sets
+agree in all their three couplets of fingers; four sets agree in two; five
+sets agree in one of the couplets. There are instances of partial
+agreement in five others, and a disagreement throughout in only one of the
+seventeen sets. In another collection of seventeen sets, made to compare
+with this, six agreed in two of their three couplets, and five agreed in
+one of them. There cannot then be the slightest doubt as to the strong
+tendency to resemblance in the finger patterns in twins.
+
+This remark must by no means be forced into the sense of meaning that the
+similarity is so great, that the finger print of one twin might
+occasionally be mistaken for that of the other. When patterns fall into
+the same class, their general forms may be conspicuously different (see p.
+74), while their smaller details, namely, the number of ridges and the
+minutiae, are practically independent of the pattern.
+
+It may be mentioned that I have an inquiry in view, which has not yet been
+fairly begun, owing to the want of sufficient data, namely to determine
+the minutest biological unit that may be hereditarily transmissible. The
+minutiae in the finger prints of twins seem suitable objects for this
+purpose.
+
+_Children of like-patterned Parents._--When two parents are alike, the
+average resemblance, in stature at all events, which their children bear
+to them, is as close as the fraternal resemblance between the children,
+and twice as close as that which the children bear to either parent
+separately, when the parents are unlike.
+
+The fifty-eight parentages affording fifty couplets of the fore, middle,
+and ring-fingers respectively give 58 x 3 = 174 parental couplets in all;
+of these, 27 or 14 per cent are alike in their pattern, as shown by Table
+XXVIII. The total number of children to these twenty-seven pairs is 109,
+of which 59 (or 54 per cent) have the same pattern as their parents. This
+fact requires analysis, as on account of the great frequency of loops, and
+especially of the pattern No. 42 on the middle finger, a large number of
+the cases of similarity of pattern between child and parents would be mere
+random coincidences.
+
+TABLE XXVIII.--_Children of like-patterned Parents._
+
+ +-------------------------------------------------------------------+
+ | The 27 | Patterns of-- F. M. | --of Sons. | Alike. | Total |
+ | cases. | | | | sons. |
+ |--------|-----------------------|-----------------|--------|-------|
+ | 1 | Fore 1 1 | 1 | 1 | 1 |
+ | 2 | 34 34 | 34 | 1 | 1 |
+ | 3 | 40 40 | 41 | ... | 1 |
+ | 4 | 42 42 | 48 | ... | 1 |
+ | | | | | |
+ | 5 | Middle 40 40 | 40 | 1 | 1 |
+ | 6 | 42 42 | 42 | 1 | 1 |
+ | 7 | 42 42 | 42 | 1 | 1 |
+ | 8 | 42 42 | 42, 38, 42, 42 | 3 | 4 |
+ | 9 | 42 42 | 42 | 1 | 1 |
+ | 10 | 42 42 | 48, 48, 14 | 1 | 4 |
+ | 11 | 42 42 | 42 | 1 | 1 |
+ | 12 | 42 42 | 40 | ... | 1 |
+ | 13 | 42 42 | 1 | ... | 1 |
+ | 14 | 42 42 | 42 | 1 | 1 |
+ | 15 | 42 42 | 42, 46, 42 | 2 | 3 |
+ | 16 | 42 42 | 34, 42 | 1 | 2 |
+ | 17 | 42 42 | 42 | 1 | 1 |
+ | 18 | 42 42 | ... | ... | ... |
+ | | | | | |
+ | 19 | Ring 14 14 | 33, 42, 14 | 1 | 3 |
+ | 20 | 14 14 | 42, 16 | ... | 2 |
+ | 21 | 14 14 | 6 | ... | 1 |
+ | 22 | 42 42 | 40 | ... | 1 |
+ | 23 | 42 42 | 42, 42, 42 | 3 | 3 |
+ | 24 | 42 42 | ... | ... | ... |
+ | 25 | 42 42 | 42, 42 | 2 | 2 |
+ | 26 | 42 42 | 49, 14 | ... | 2 |
+ | 27 | 46 46 | 48, 40, 16 | ... | 4 |
+ | | | |--------|-------|
+ | | | | 22 | 41 |
+ | | | | | |
+ | | | | | |
+ | | | | | |
+ +-------------------------------------------------------------------+
+
+ +--------------------------------------------------------------------+
+ | --of Daughters. | Alike. | Total || Total |Alike.|
+ | | | daughters. ||children.| |
+ |----------------------------|--------|------------||---------|------|
+ | 1, 1 | 2 | 2 || 3 | 3 |
+ | 42, 48 | ... | 2 || 3 | 1 |
+ | 2, 40 | 1 | 2 || 3 | 1 |
+ | 42 | 1 | 1 || 2 | 1 |
+ | | | || | |
+ | 40 | 1 | 1 || 2 | 2 |
+ | ... | ... | ... || 1 | 1 |
+ | 40 | ... | 1 || 2 | 1 |
+ | 40, 1 | ... | 2 || 6 | 3 |
+ | 40, 42 | 1 | 2 || 3 | 2 |
+ | 42, 42, 48, 42, 42 | 4 | 5 || 9 | 5 |
+ | 1, 40 | ... | 2 || 3 | 1 |
+ | 42, 42, 42, 42 | 4 | 4 || 5 | 4 |
+ | ... | ... | ... || 1 | ... |
+ | 42, 42, 42 | 3 | 3 || 4 | 4 |
+ | 42, 42, 42, 42, 42, 42, 42 | 3 | 3 || 4 | 4 |
+ | 33, 42 | 1 | 2 || 4 | 2 |
+ | 40, 42, 1 | 1 | 3 || 4 | 2 |
+ | 42, 42 (twins) | 2 | 2 || 2 | 2 |
+ | | | || | |
+ | 32, 40 | ... | 2 || 5 | 1 |
+ | 16, 14, 42, 42 | 1 | 4 || 6 | 1 |
+ | 9, 35, 48, 32, 14 | 1 | 5 || 6 | 1 |
+ | 40 | ... | 1 || 2 | ... |
+ | 40, 42 | 1 | 2 || 5 | 4 |
+ | 40, 42 | 1 | 2 || 2 | 1 |
+ | 42, 40, 42 | 2 | 3 || 5 | 4 |
+ | 42, 42, 42 | 3 | 3 || 5 | 3 |
+ | 16, 38 | ... | 2 || 6 | ... |
+ | |--------|------------||---------|------|
+ | Daughters | 37 | 65 || | |
+ | Sons | 22 | 44 || | |
+ | |--------|------------|| | |
+ | Total Children | 59 | 109 || 109 | 59 |
+ +--------------------------------------------------------------------+
+
+There are nineteen cases of both parents having the commonest of the loop
+patterns, No. 42, on a corresponding finger. They have between them
+seventy-five children, of whom forty-eight have the pattern No. 42, on the
+same finger as their parents, and eighteen others have loops of other
+kinds on that same finger, making a total of sixty-six coincidences out of
+the possible 75, or 88 per cent, which is a great increase upon the normal
+proportion of loops of the No. 42 pattern in the fore, middle, and
+ring-fingers collectively. Again, there are three cases of both parents
+having a tendrilled-loop No. 15, which ranks as a whorl. Out of their
+total number of seventeen children, eleven have whorls and only six have
+loops.
+
+Lastly, there is a single case of both parents having an arch, and all
+their three children have arches; whereas in the total of 109 children in
+the table, there are only four other cases of an arch.
+
+This partial analysis accounts for the whole of the like-patterned
+parents, except four couples, which are one of No. 34, two of No. 40, and
+one of No. 46. These concur in telling the same general tale, recollecting
+that No. 46 might almost be reckoned as a transitional case between a loop
+and a whorl.
+
+The decided tendency to hereditary transmission cannot be gainsaid in the
+face of these results, but the number of cases is too few to justify
+quantitative conclusions. It is not for the present worth while to extend
+them, for the reason already mentioned, namely, an ignorance of the
+allowance that ought to be made for related patterns. On this account it
+does not seem useful to print the results of a large amount of tabulation
+bearing on the simple filial relationship between the child and either
+parent separately, except so far as appears in the following paragraph.
+
+_Relative Influence of the Father and the Mother._--Through one of those
+statistical accidents which are equivalent to long runs of luck at a
+gaming table, a concurrence in the figures brought out by Mr. Collins
+suggested to him the existence of a decided preponderance of maternal
+influence in the hereditary transmission of finger patterns. His further
+inquiries have, however, cast some doubt on earlier and provisional
+conclusions, and the following epitomises all of value that can as yet be
+said in favour of the superiority of the maternal influence.
+
+The fore, middle, and ring-fingers of the right hands of the father,
+mother, and all their accessible children, in many families, were
+severally tabulated under the fifty-three heads already specified. The
+total number of children was 389, namely 136 sons and 219 daughters. The
+same pattern was found on the same finger, both of a child and of one or
+other of his parents, in the following number of cases:--
+
+TABLE XXIX.
+
+_Relative Influence of Father and Mother._
+
+ +----------------------------------------------------------------------+
+ | |Fore.|Middle.|Ring.|| Totals. | Corrected | |
+ | | | | || | Totals. | |
+ |---------------------|-----|-------|-----||---------|-----------|-----|
+ | Father and son | 17 | 35 | 28 || 80 | 80 |}149 |
+ | " " daughter | 29 | 52 | 30 || (111) | 69 |} |
+ | | | | || | | |
+ | Mother and son | 18 | 50 | 26 || 94 | 94 |}186 |
+ | " " daughter | 38 | 75 | 35 || (148) | 92 |} |
+ +----------------------------------------------------------------------+
+
+The entries in the first three columns are not comparable on equal terms,
+on account of the large difference between the numbers of the sons and
+daughters. This difference is easily remedied by multiplying the number of
+daughters by 136/219, that is by 0.621, as has been done in the fifth
+column headed Corrected Totals. It would appear from these figures, that
+the maternal influence is more powerful than the paternal in the
+proportion of 186 to 149, or as 5 to 4; but, as some of the details from
+which the totals are built up, vary rather widely, it is better for the
+present to reserve an opinion as to their trustworthiness.
+
+
+
+
+CHAPTER XII
+
+RACES AND CLASSES
+
+
+The races whose finger prints I have studied in considerable numbers are
+English, pure Welsh, Hebrew, and Negro; also some Basques from Cambo in
+the French Pyrenees, twenty miles south-east of Bayonne. For the Welsh
+prints I am primarily indebted to the very obliging help of Mr. R. W.
+Atkinson, of Cardiff, who interested the masters of schools in purely
+Welsh-speaking mountainous districts on my behalf; for the Hebrew prints
+to Mr. Isidore Spielman, who introduced me to the great Hebrew schools in
+London, whose head-masters gave cordial assistance; and for the Negro
+prints to Sir George Taubman Goldie, Dep. Governor of the Royal Niger Co.,
+who interested Dr Crosse on my behalf, from whom valuable sets of prints
+were received, together with particulars of the races of the men from whom
+they were made. As to the Basques, they were printed by myself.
+
+It requires considerable patience and caution to arrive at trustworthy
+conclusions, but it may emphatically be said that there is no _peculiar_
+pattern which characterises persons of any of the above races. There is
+no particular pattern that is special to any one of them, which when met
+with enables us to assert, or even to suspect, the nationality of the
+person on whom it appeared. The only differences so far observed, are
+statistical, and cannot be determined except through patience and caution,
+and by discussing large groups.
+
+I was misled at first by some accidental observations, and as it seemed
+reasonable to expect to find racial differences in finger marks, the
+inquiries were continued in varied ways until hard fact had made hope no
+longer justifiable.
+
+After preliminary study, I handed over the collection of racial finger
+prints to Mr F. Howard Collins, who kindly undertook the labour of
+tabulating them in many ways, of which it will be only necessary to give
+an example. Thus, at one time attention was concentrated on a single
+finger and a single pattern, the most instructive instance being that of
+arches on the right fore-finger. They admit of being defined with
+sufficient clearness, having only one doubtful frontier of much
+importance, namely that at which they begin to break away into
+nascent-loops, etc. They also occur with considerable frequency on the
+fore-finger, so the results from a few hundred specimens ought to be
+fairly trustworthy. It mattered little in the inquiry, at what level the
+limit was drawn to separate arches from nascent-loops, so long as the same
+limit was observed in all races alike. Much pains were taken to secure
+uniformity of treatment, and Mr. Collins selected two limits, the one
+based on a strict and the other on a somewhat less strict interpretation
+of the term "arches," but the latter was not so liberal as that which I
+had used myself in the earlier inquiries (see p. 114). His results showed
+no great difference in the proportionate frequency of arches in the
+different races, whichever limit was observed; the following table refers
+to the more liberal limit:--
+
+TABLE XXX.
+
+_Frequency of Arches in the Right Fore-Finger._
+
+ +--------------------------------------------------------------------+
+ | No. of | Race. | No. of | Per Cents. |
+ | Persons. | | Arches. | |
+ |----------|----------------------------------|---------|------------|
+ | 250 | English | 34 | 13.6 |
+ | 250 | Welsh | 26 | 10.8 |
+ | 1332 | Hebrew | 105 | 7.9 |
+ | 250 | Negro | 27 | 11.3 |
+ | | | | |
+ | | _Hebrews in detail_-- | | |
+ | 500 | Boys, Bell Lane School | 35 | 7.0 |
+ | 400 | Girls, Bell Lane School | 34 | 8.5 |
+ | 220 | Boys, Tavistock St. & Hanway St. | 18 | 8.2 |
+ | 212 | Girls, Hanway Street School | 18 | 8.5 |
+ +--------------------------------------------------------------------+
+
+The two contrasted values here are the English and the Hebrew. The 1332
+cases of the latter give a percentage result of 7.9, which differs as may
+be seen less than 1 per cent from that of any one of the four large groups
+upon which the average is based. The 250 cases of English are
+comparatively few, but the experience I have had of other English prints
+is so large as to enable me to say confidently that the percentage result
+of 13.6 is not too great. It follows, that the percentage of arches in the
+English and in the Hebrew differs in the ratio of 13.6 to 7.9, or nearly
+as 5 to 3. This is the largest statistical difference yet met with. The
+deficiency in arches among the Hebrews, and to some extent in loops also,
+is made up by a superiority in whorls, chiefly of the tendril or
+circlet-in-loop patterns.
+
+It would be very rash to suppose that this relative infrequency of arches
+among the Hebrews was of fundamental importance, considering that such
+totally distinct races as the Welsh and the Negro have them in an
+intermediate proportion. Still, why does it occur? The only answer I can
+suggest is that the patterns being in some degree hereditary, such
+accidental preponderances as may have existed among a not very numerous
+ancestry might be perpetuated. I have some reason to believe that local
+peculiarities of this sort exist in England, the children in schools of
+some localities seeming to be statistically more alike in their patterns
+than English children generally.
+
+Another of the many experiments was the tabulation separately by Mr.
+Collins of the fore, middle, and ring-fingers of the right hand of fifty
+persons of each of the five races above-mentioned: English, Welsh, Basque,
+Hebrew, and different groups of Negroes. The number of instances is of
+course too small for statistical deductions, but they served to make it
+clear that no very marked characteristic distinguished the races. The
+impressions from Negroes betray the general clumsiness of their fingers,
+but their patterns are not, so far as I can find, different from those of
+others, they are not simpler as judged either by their contours or by the
+number of origins, embranchments, islands, and enclosures contained in
+them. Still, whether it be from pure fancy on my part, or from the way in
+which they were printed, or from some real peculiarity, the general aspect
+of the Negro print strikes me as characteristic. The width of the ridges
+seems more uniform, their intervals more regular, and their courses more
+parallel than with us. In short, they give an idea of greater simplicity,
+due to causes that I have not yet succeeded in submitting to the test of
+measurement.
+
+The above are only a few examples of the laborious work so kindly
+undertaken for me by Mr. F. H. Collins, but it would serve no useful
+purpose to give more in this book, as no positive results have as yet been
+derived from it other than the little already mentioned.
+
+The most hopeful direction in which this inquiry admits of being pursued
+is among the Hill tribes of India, Australian blacks, and other diverse
+and so-called aboriginal races. The field of ethnology is large, and it
+would be unwise as yet to neglect the chance of somewhere finding
+characteristic patterns.
+
+ * * * * *
+
+Differences between finger prints of different classes might continue to
+exist although those of different races are inconspicuous, because every
+race contains men of various temperaments and faculties, and we cannot
+tell, except by observation, whether any of these are correlated with the
+finger marks. Several different classes have been examined both by Mr.
+Collins and myself. The ordinary laboratory work supplies finger prints of
+persons of much culture, and of many students both in the Art and in the
+Science schools. I took a large number of prints from the worst idiots in
+the London district, through the obliging assistance of Dr. Fletcher
+Beech, of the Darenth Asylum; my collections made at Board Schools are
+numerous, and I have one of field labourers in Dorsetshire and
+Somersetshire. But there is no notable difference in any of them. For
+example; the measurements of the ridge-interval gave the same results in
+the art-students and in the science-students, and I have prints of eminent
+thinkers and of eminent statesmen that can be matched by those of
+congenital idiots.[5] No indications of temperament, character, or ability
+are to be found in finger marks, so far as I have been able to discover.
+
+Of course these conclusions must not be applied to the general shape of
+the hand, which as yet I have not studied, but which seems to offer a very
+interesting field for exact inquiry.
+
+
+
+
+CHAPTER XIII
+
+GENERA
+
+
+The same familiar patterns recur in every large collection of finger
+prints, and the eye soon selects what appear to be typical forms; but are
+they truly "typical" or not? By a type I understand an ideal form around
+which the actual forms are grouped, very closely in its immediate
+neighbourhood, and becoming more rare with increasing rapidity at an
+increasing distance from it, just as is the case with shot marks to the
+right or left of a line drawn vertically through the bull's eye of a
+target. The analogy is exact; in both cases there is a well-defined point
+of departure; in both cases the departure of individual instances from
+that point is due to a multitude of independently variable causes. In
+short, both are realisations of the now well-known theoretical law of
+Frequency of Error. The problem then is this:--take some one of the
+well-marked patterns, such as it appears on a particular digit,--say a
+loop on the right thumb; find the average number of ridges that cross a
+specified portion of it; then this average value will determine an ideal
+centre from which individual departures may be measured; next, tabulate
+the frequency of the departures that attain to each of many successive
+specified distances from that ideal centre; then see whether their
+diminishing frequency as the distances increase, is or is not in
+accordance with the law of frequency of error. If it is, then the central
+form has the attributes of a true type, and such will be shown to be the
+case with the loops of either thumb. I shall only give the data and the
+results, not the precise way in which they are worked out, because an
+account of the method employed in similar cases will be found in _Natural
+Inheritance_, and again in the Memoir on Finger Prints in the _Phil.
+Trans._; it is too technical to be appropriate here, and would occupy too
+much space. The only point which need be briefly explained and of which
+non-mathematical readers might be ignorant, is how a single numerical
+table derived from abstract calculations can be made to apply to such
+minute objects as finger prints, as well as to the shot marks on a huge
+target; what is the common unit by which departures on such different
+scales are measured? The answer is that it is a self-contained unit
+appropriate to _each series severally_, and technically called the
+Probable Error, or more briefly, P.E., in the headings to the following
+tables. In order to determine it, the range of the central half of the
+series has to be measured, namely, of that part of the series which
+remains after its two extreme quarters have been cut off and removed. The
+series had no limitation before, its two ends tailing away indefinitely
+into nothingness, but, by the artifice of lopping off a definite fraction
+of the whole series from both ends of it, a sharply-defined length, call
+it PQ, is obtained. Such series as have usually to be dealt with are
+fairly symmetrical, so the position of the half-way point M, between P and
+Q, corresponds with rough accuracy to the average of the positions of all
+the members of the series, that is to the point whence departures have to
+be measured. MP, or MQ,--or still better, 1/2(MP + MQ) is the
+above-mentioned Probable Error. It is so called because the amount of
+Error, or Departure from M of any one observation, falls just as often
+within the distance PE as it falls without it. In the calculated tables of
+the Law of Frequency, PE (or a multiple of it) is taken as unity. In each
+observed series, the actual measures have to be converted into another
+scale, in which the PE of that series is taken as unity. Then observation
+and calculation may be compared on equal terms.
+
+
+[Illustration]
+
+
+Observations were made on the loops of the right and left thumbs
+respectively. AHB is taken as the primary line of reference in the loop;
+it is the line that, coinciding with the axis of the _uppermost portion_,
+and that only, of the core, cuts the summit of the core at H, the upper
+outline at A, and the lower outline, if it cuts it at all, as it nearly
+always does, at B. K is the centre of the single triangular plot that
+appears in the loop, which may be either I or O. KNL is a perpendicular
+from K to the axis, cutting it at N, and the outline beyond at L. In some
+loops N will lie above H, as in Plate 4, Fig. 8; in some it may coincide
+with H. (See Plate 6 for numerous varieties of loop.) These points were
+pricked in each print with a fine needle; the print was then turned face
+downwards and careful measurements made between the prick holes at the
+back. Also the number of ridges in AH were counted, the ridge at A being
+reckoned as 0, the next ridge as 1, and so on up to H. Whenever the line
+AH passed across the neck of a bifurcation, there was necessarily a single
+ridge on one side of the point of intersection and two ridges on the
+other, so there would clearly be doubt whether to reckon the neck as one
+or as two ridges. A compromise was made by counting it as 1-1/2. After the
+number of ridges in AH had been counted in each case, any residual
+fractions of 1/2 were alternately treated as 0 and as 1. Finally, six
+series were obtained; three for the right thumb, and three for the left.
+They referred respectively (1) to the Number of Ridges in AH; (2) to
+KL/NB; (3) to AN/AH, all the three being independent of stature. The
+number of measures in each of the six series varied from 140 to 176; they
+are reduced to percentages in Table XXXI.
+
+We see at a glance that the different numbers of ridges in AH do not occur
+with equal frequency, that a single ridge in the thumb is a rarity, and so
+are cases above fifteen in number, but those of seven, eight, and nine
+are frequent. There is clearly a rude order in their distribution, the
+number of cases tailing away into nothingness, at the top and bottom of
+the column. A vast amount of statistical analogy assures us that the
+orderliness of the distribution would be increased if many more cases had
+been observed, and later on, this inference will be confirmed. There is a
+sharp inferior limit to the numbers of ridges, because they cannot be less
+than 0, but independently of this, we notice the infrequency of small
+numbers as well as of large ones. There is no strict limit to the latter,
+but the trend of the entries shows that forty, say, or more ridges in AH
+are practically impossible. Therefore, in no individual case can the
+number of ridges in AH depart very widely from seven, eight, or nine,
+though the range of possible departures is not sharply defined, except at
+the lower limit of 0. The range of variation is _not_ "rounded off," to
+use a common but very inaccurate expression often applied to the way in
+which genera are isolated. The range of possible departures is not defined
+by any rigid boundary, but the rarity of the stragglers rapidly increases
+with the distance at which they are found, until no more of them are met
+with.
+
+The values of KL/NB and of AN/AH run in a less orderly sequence, but
+concur distinctly in telling a similar tale. Considering the paucity of
+the observations, there is nothing in these results to contradict the
+expectation of increased regularity, should a large addition be made to
+their number.
+
+TABLE XXXI.
+
+ +---------------------------------------------------------------------+
+ | | No. of cases || | No. of cases || | No. of cases |
+ | | reduced || | reduced || | reduced |
+ |No. of| to per cents.|| KL | to per cents.|| AN | to per cents.|
+ |ridges|--------------|| -- |--------------|| -- |--------------|
+ |in AH.| Right.| Left.|| NB | Right.| Left.|| AH | Right.| Left.|
+ | |-------|------|| |-------|------|| |-------|------|
+ | | 171 | 166 || | 149 | 140 || | 176 | 163 |
+ | | cases.| cases|| | cases.| cases|| | cases | cases|
+ |------|-------|------||-------|-------|------||-------|-------|------|
+ | 1 | 1 | ... ||0.3-0.4| 3 | 2 ||0.1-0.2| 2 | 1 |
+ | 2 | 2 | 1 ||0.5-0.6| 8 | 11 ||0.3-0.4| 7 | 3 |
+ | 3 | 2 | 3 ||0.7-0.8| 9 | 14 ||0.5-0.6| 11 | 3 |
+ | 4 | 2 | 5 ||0.9-1.0| 21 | 18 ||0.7-0.8| 9 | 9 |
+ | 5 | 3 | 5 ||1.1-1.2| 16 | 23 ||0.9-1.0| 22 | 15 |
+ | 6 | 4 | 18 ||1.3-1.4| 24 | 7 ||1.1-1.2| 15 | 13 |
+ | 7 | 8 | 14 ||1.5-1.6| 8 | 10 ||1.3-1.4| 12 | 12 |
+ | 8 | 8 | 16 ||1.7-1.8| 3 | 6 ||1.5-1.6| 11 | 14 |
+ | 9 | 11 | 10 ||1.9-2.0| 5 | 6 ||1.7-1.8| 8 | 10 |
+ | 10 | 9 | 8 ||2.1-2.2| 1 | 1 ||1.9-2.0| 1 | 5 |
+ | 11 | 14 | 10 || above | 2 | 2 ||2.1-2.2| ... | ... |
+ | 12 | 11 | 8 || ... | ... | ... ||2.3-2.4| 1 | 6 |
+ | 13 | 10 | 2 || ... | ... | ... ||2.5-2.6| ... | 4 |
+ | 14 | 7 | ... || ... | ... | ... ||2.7-2.8| ... | 3 |
+ | 15 | 6 | ... || ... | ... | ... ||2.9-3.0| ... | 1 |
+ |above | 2 | ... || ... | ... | ... || above | 1 | 1 |
+ | |-------|------|| |-------|------|| |-------|------|
+ | | 100 | 100 || | 100 | 100 || | 100 | 100 |
+ +---------------------------------------------------------------------+
+
+TABLE XXXII.
+
+ +---------------------------------------------+
+ | |Ordinates to the six schemes of |
+ | |Distribution, being the ordinates|
+ | |drawn from the base of each |
+ | |scheme at selected centesimal |
+ | |divisions of the base. |
+ | Abscissae |---------------------------------|
+ | reckoned | |
+ | in | No. of ridges in AH. |
+ | centesimal| |
+ | parts of |---------------------------------|
+ | the | Right. | Left. |
+ | interval |----------------|----------------|
+ | between | O |Calculated| O |Calculated|
+ | the limits| b |from | b |from |
+ | of the | s |M=10.4 | s |M=7.8 |
+ | scheme. | e |p.e.=2.3 | e |p.e.=1.9 |
+ | 0 deg. to | r | | r | |
+ | 100 deg. | v | | v | |
+ | | e | | e | |
+ | | d | | d | |
+ |-----------|-----|----------|-----|----------|
+ | 5 | 3.8 | 4.8 | 3.8 | 3.2 |
+ | 10 | 5.5 | 6.0 | 4.8 | 4.2 |
+ | 20 | 7.3 | 7.5 | 5.8 | 5.4 |
+ | 25 | 7.9 | 8.1 | 6.1 | 5.9 |
+ | 30 | 8.5 | 8.6 | 6.4 | 6.3 |
+ | 40 | 9.5 | 9.5 | 7.1 | 7.4 |
+ | 50 |10.5 | 10.4 | 7.8 | 7.8 |
+ | 60 |11.3 | 11.3 | 8.4 | 8.2 |
+ | 70 |12.1 | 12.2 | 9.3 | 9.3 |
+ | 75 |12.5 | 12.7 | 9.9 | 9.7 |
+ | 80 |13.0 | 13.3 |11.0 | 10.2 |
+ | 90 |14.3 | 14.8 |11.5 | 11.4 |
+ | 95 |15.0 | 16.0 |12.2 | 12.2 |
+ +---------------------------------------------+
+
+ +---------------------------------------------------------------------+
+ | KL || AN |
+ | Values of -- || Values of -- |
+ | NB || AH |
+ |---------------------------------||----------------------------------|
+ | Right. | Left. || Right. | Left. |
+ |----------------|----------------||----------------|-----------------|
+ | O |Calculated| O |Calculated|| O |Calculated| O |Calculated |
+ | b |from | b |from || b |from | b |from |
+ | s |M=1.15 | s |M=1.10 || s |M=1.08 | s |M=1.36 |
+ | e |p.e.=0.25 | e |p.e.=0.31 || e |p.e.=0.30 | e |p.e.=0.36 |
+ | r | | r | || r | | r | |
+ | v | | v | || v | | v | |
+ | e | | e | || e | | e | |
+ | d | | d | || d | | d | |
+ |-----|----------|-----|----------||-----|----------|-----|-----------|
+ |0.54 | 0.54 |0.49 | 0.35 ||0.36 | 0.32 |0.58 | 0.48 |
+ |0.64 | 0.67 |0.59 | 0.51 ||0.50 | 0.48 |0.74 | 0.68 |
+ |0.85 | 0.84 |0.78 | 0.71 ||0.66 | 0.67 |0.96 | 0.91 |
+ |0.91 | 0.90 |0.83 | 0.79 ||0.79 | 0.75 |1.00 | l.00 |
+ |0.99 | 0.95 |0.89 | 0.86 ||0.87 | 0.82 |1.04 | 1.08 |
+ |1.05 | 1.05 |1.00 | 0.98 ||0.98 | 0.93 |1.21 | 1.22 |
+ |1.15 | 1.15 |1.10 | 1.10 ||1.04 | 1.05 |1.37 | 1.36 |
+ |1.29 | 1.25 |1.18 | 1.22 ||1.18 | 1.17 |1.48 | 1.50 |
+ |1.33 | 1.35 |1.32 | 1.34 ||1.31 | 1.28 |1.66 | 1.64 |
+ |1.41 | 1.40 |1.46 | 1.41 ||1.39 | 1.35 |1.73 | 1.72 |
+ |1.45 | 1.46 |1.53 | 1.49 ||1.48 | 1.43 |1.90 | 2.81 |
+ |1.77 | 1.63 |1.73 | 1.69 ||1.69 | 1.62 |2.23 | 2.04 |
+ |2.00 | 1.76 |1.80 | 1.85 ||1.81 | 1.78 |2.48 | 2.24 |
+ +---------------------------------------------------------------------+
+
+TABLE XXXIII.
+
+ +-------------------------------------------------------
+ | | Ordinates to the six curves of |
+ | | distribution, drawn from the axis of |
+ | | each curve at selected centesimal |
+ | | divisions of it. |
+ | | |
+ | | They are here reduced to a common |
+ | | measure, by dividing the observed |
+ | | deviations in each series by the |
+ |Abscissae | probable error appropriate to the |
+ |reckoned in | series, and multiplying by 100. For the |
+ |centesimal | values of M, whence the deviations are |
+ |parts of the| measured, and for those of the |
+ |interval | corresponding probable error, see the |
+ |between the | headings to the columns in Table II. |
+ |limits of |-----------------------------------------|
+ |the curve. | No. of | KL | AN |
+ |0 deg.to100deg. | Ridges |Values of -- |Values of -- |
+ | | in AH. | NB | AH |
+ | |-------------|-------------|-------------|
+ | |Right.| Left.|Right.| Left.|Right.| Left.|
+ |------------|------|------|------|------|-------------|
+ | 5 | -291 | -211 | -244 | -196 | -230 | -217 |
+ | 10 | -213 | -158 | -204 | -164 | -183 | -172 |
+ | 20 | -135 | -105 | -120 | -103 | -130 | -111 |
+ |(P) 25 | -109 | - 84 | - 92 | - 87 | - 87 | -100 |
+ | 30 | - 83 | - 74 | - 64 | - 68 | - 60 | - 89 |
+ | 40 | - 44 | - 37 | - 44 | - 31 | - 23 | - 42 |
+ |(M) 50 | + 4 | 0 | 0 | 0 | 0 | 0 |
+ | 60 | + 39 | + 31 | + 56 | + 23 | + 43 | + 33 |
+ | 70 | + 74 | + 79 | + 72 | + 68 | + 87 | + 83 |
+ |(Q) 75 | + 91 | +116 | +104 | +116 | +113 | +103 |
+ | 80 | +113 | +168 | +120 | +138 | +143 | +150 |
+ | 90 | +170 | +200 | +248 | +203 | +213 | +242 |
+ | 95 | +200 | +231 | +340 | +225 | +253 | +311 |
+ +-------------------------------------------------------
+
+ -------------------------------------+
+ | | |
+ | Observed. | Calculated. |
+ |------------------|-----------------|
+ | Mean of the | |
+ | corresponding | |
+ | ordinates in | |
+ | the six curves | |
+ | after reduction | |
+ | to the common | Ordinates to |
+ | scale of | the normal curve|
+ | p.e. = 100. | of distribution,|
+ | 965 observations | probable error |
+ | in all. | = 100. |
+ |------------------|-----------------|
+ | -231 | -244 |
+ | -182 | -190 |
+ | -117 | -125 |
+ | - 93 | -100 |
+ | - 73 | - 78 |
+ | - 37 | - 38 |
+ | + 1 | 0 |
+ | + 38 | + 38 |
+ | + 77 | + 78 |
+ | +107 | +100 |
+ | +139 | +125 |
+ | +213 | +190 |
+ | +260 | +244 |
+ -------------------------------------+
+
+Table XXXII. is derived from Table XXXI. by a process described by myself
+in many publications, more especially in _Natural Inheritance_, and will
+now be assumed as understood. Each of the six pairs of columns contain,
+side by side, the Observed and Calculated values of one of the six series,
+the data on which the calculations were made being also entered at the
+top. The calculated figures agree with the observed ones very respectably
+throughout, as can be judged even by those who are ignorant of the
+principles of the method. Let us take the value that 10 per cent of each
+of the six series falls short of, and 90 per cent exceed; they are entered
+in the line opposite 10; we find for the six pairs successively,
+
+ _Obs._: 5.5 4.8 0.64 0.59 0.50 0.74
+
+ _Calc._: 6.0 4.2 0.67 0.51 0.48 0.68
+
+The correspondence between the more mediocre cases is much closer than
+these, and very much closer than between the extreme cases given in the
+table, namely, the values that 5 per cent fall short of, and 95 exceed.
+These are of course less regular, the observed instances being very few;
+but even here the observations are found to agree respectably well with
+the proportions given by calculation, which is necessarily based upon the
+supposition of an infinite number of cases having been included in the
+series.
+
+As the want of agreement between calculation and observation must be
+caused in part by the paucity of observations, it is worth while to make
+a larger group, by throwing the six series together, as in Table XXXIII.,
+making a grand total of 965 observations. Their value is not so great as
+if they were observations taken from that number of different persons,
+still they are equivalent to a large increase of those already discussed.
+The six series of observed values were made comparable on equal terms by
+first reducing them to a uniform PE and then by assigning to M, the point
+of departure, the value of 0. The results are given in the last column but
+one, where the orderly run of the observed data is much more conspicuous
+than it was before. Though there is an obvious want of exact symmetry in
+the observed values, their general accord with those of the calculated
+values is very fair. It is quite close enough to establish the general
+proposition, that we are justified in the conception of a typical form of
+loop, different for the two thumbs; the departure from the typical form
+being usually small, sometimes rather greater, and rarely greater still.
+
+I do not see my way to discuss the variations of the arches, because they
+possess no distinct points of reference. But their general appearance does
+not give the impression of clustering around a typical centre. They
+suggest the idea of a fountain-head, whose stream begins to broaden out
+from the first.
+
+As regards other patterns, I have made many measurements altogether, but
+the specimens of each sort were comparatively few, except in whorled
+patterns. In all cases where I was able to form a well-founded opinion,
+the existence of a typical centre was indicated.
+
+It would be tedious to enumerate the many different trials made for my own
+satisfaction, to gain assurance that the variability of the several
+patterns is really of the quasi-normal kind just described. In the first
+trial I measured in various ways the dimensions of about 500 enlarged
+photographs of loops, and about as many of other patterns, and found that
+the measurements in each and every case formed a quasi-normal series. I do
+not care to submit these results, because they necessitate more
+explanation and analysis than the interest of the corrected results would
+perhaps justify, to eliminate from them the effect of variety of size of
+thumb, and some other uncertainties. Those measurements referred to some
+children, a few women, many youths, and a fair number of adults; and
+allowance has to be made for variability in stature in each of these
+classes.
+
+The proportions of a typical loop on the thumb are easily ascertained if
+we may assume that the most frequent values of its variable elements,
+taken separately, are the same as those that enter into the most frequent
+combination of the elements taken collectively. This would necessarily be
+true if the variability of each element separately, and that of the sum of
+them in combination, were all strictly normal, but as they are only
+quasi-normal, the assumption must be tested. I have done so by making the
+comparisons (_A_) and (_B_) shown in Table XXXIV., which come out
+correctly to within the first decimal place.
+
+TABLE XXXIV.
+
+ +------------------------------------------------------+
+ | |Right | Left |
+ | |Thumb.|Thumb.|
+ |----------------------------------------|------|------|
+ |(_a_) Median of all the values of KL | 12.5 | 10.1 |
+ |(_b_) Median of all the values of NB | 10.1 | 8.9 |
+ | |------|------|
+ |(_A_) Value of _a/b_ | 1.24| 1.11|
+ |(_A_) Median of all the fractions KL/NB| 1.15| 1.10|
+ |========================================|======|======|
+ |(_c_) Median of all the values of AN | 4.6 | 4.6 |
+ |(_d_) Median of all the values of AH | 4.4 | 3.3 |
+ | |------|------|
+ |(_B_) Value of _c/d_ | 1.05| 1.40|
+ |(_B_) Median of all the fractions AN/AH| 1.08| 1.36|
+ +------------------------------------------------------+
+
+It has been shown that the patterns are hereditary, and we have seen that
+they are uncorrelated with race or temperament or any other noticeable
+peculiarity, inasmuch as groups of very different classes are alike in
+their finger marks. They cannot exercise the slightest influence on
+marriage selection, the very existence both of the ridges and of the
+patterns having been almost overlooked; they are too small to attract
+attention, or to be thought worthy of notice. We therefore possess a
+perfect instance of promiscuity in marriage, or, as it is now called,
+panmixia, in respect to these patterns. We might consequently have
+expected them to be hybridised. But that is not the case; they _refuse to
+blend_. Their classes are as clearly separated as those of any of the
+genera of plants and animals. They keep pure and distinct, as if they had
+severally descended from a thorough-bred ancestry, each in respect to its
+own peculiar character.
+
+As regards other forms of natural selection, we know that races are kept
+pure by the much more frequent destruction of those individuals who depart
+the more widely from the typical centre. But natural selection was shown
+to be inoperative in respect to individual varieties of patterns, and
+unable to exercise the slightest check upon their vagaries. Yet, for all
+that, the loops and other classes of patterns are isolated from one
+another just as thoroughly and just in the same way as are the genera or
+species of plants and animals. There is no statistical difference between
+the form of the law of distribution of individual Loops about their
+respective typical centres, and that of the law by which, say, the Shrimps
+described in Mr. Weldon's recent memoirs (_Proc. Roy. Soc._, 1891 and
+1892) are distributed about theirs. In both cases the distribution is in
+quasi-accordance with the theoretical law of Frequency of Error, this form
+of distribution being entirely caused in the patterns, by _internal_
+conditions, and in no way by natural selection in the ordinary sense of
+that term.
+
+It is impossible not to recognise the fact so clearly illustrated by these
+patterns in the thumbs, that natural selection has no monopoly of
+influence in the construction of genera, but that it could be wholly
+dispensed with, the internal conditions acting by themselves being
+sufficient. When the internal conditions are in harmony with the external
+ones, as they appear to be in all long-established races, their joint
+effects will curb individual variability more tightly than either could do
+by itself. The normal character of the distribution about the typical
+centre will not be thereby interfered with. The probable divergence (=
+probable error) of an individual taken at random, will be lessened, and
+that is all.
+
+Not only is it impossible to substantiate a claim for natural selection,
+that it is the sole agent in forming genera, but it seems, from the
+experience of artificial selection, that it is scarcely competent to do so
+by favouring mere _varieties_, in the sense in which I understand the
+term.
+
+My contention is that it acts by favouring small _sports_. Mere varieties
+from a common typical centre blend freely in the offspring, and the
+offspring of every race whose _statistical_ characters are constant,
+necessarily tend, as I have often shown, to regress towards their common
+typical centre. Sports, on the other hand, do not blend freely; they are
+fresh typical centres or sub-species, which suddenly arise we do not yet
+know precisely through what uncommon concurrence of circumstance, and
+which observations show to be strongly transmissible by inheritance.
+
+A mere variety can never establish a sticking-point in the forward course
+of evolution, but each new sport affords one. A substantial change of type
+is effected, as I conceive, by a succession of small changes of typical
+centre, each more or less stable, and each being in its turn favoured and
+established by natural selection, to the exclusion of its competitors. The
+distinction between a mere variety and a sport is real and fundamental. I
+argued this point in _Natural Inheritance_, but had then to draw my
+illustrations from non-physiological experiences, no appropriate
+physiological ones being then at hand: this want is now excellently
+supplied by observations of the patterns on the digits.
+
+
+
+
+INDEX
+
+
+ AH, number of ridges in, 200
+
+ Allix, 60
+
+ A. L. W. system, 80
+
+ Ambiguities in minutiae, 91, 111
+
+ America, 163
+
+ Anthropometric laboratory, 4, 35
+
+ Arches, 7, 75, 78;
+ interpretations of, 114, 193
+
+ Artisans, 59
+
+ Artists, 58
+
+ Assyrian bricks, 25
+
+ Atkinson, R. F., 192
+
+ Author, the, finger prints of, 8, 58, 73
+
+ Axis of pattern, 68
+
+
+ Ball for inking, 42
+
+ Ball of thumb, 96
+
+ Basques, 18, 192
+
+ Bearings as by compass, 84
+
+ Beech, Dr. Fletcher, 197
+
+ Benzole, 36, 41
+
+ Bertillon, 2, 15, 154, 169;
+ _Bertillonage_, 155, 164, 167
+
+ Bewick, 26
+
+ Bible, the, 22
+
+ Bifurcations, 91
+
+ Binomial law, 11, 112
+
+ Bird's nest, 34
+
+ Blacklead, 49
+
+ Blood as ink, 45
+
+ Bowditch, H. P., Professor, 47
+
+ British Museum, 25
+
+ Brobdingnags, 1
+
+ Brothers, 171
+
+ Burns of finger, 59
+
+
+ C. set of standard patterns, 177
+
+ Callosities, 59
+
+ Cambo, 18, 192
+
+ Camera lucida, 52, 104
+
+ Cards, 38;
+ keeping in order, 145
+
+ Casts, 49
+
+ Centesimal scale, 12, 17, 124, 129, 182
+
+ Cheiromancy, 1, 26;
+ creases, 56
+
+ Chequer-work, 106
+
+ Chess board, 106
+
+ Chinese deed, 24;
+ money, 25;
+ cheiromancy, 26;
+ registration of Chinese, 26, 152
+
+ Cicatrix, 59
+
+ Circular patterns, optical illusion, 77
+
+ Collins, F. H., 17, 21, 177, 190, 193
+
+ Collodion, 51
+
+ Colour-blindness, 71
+
+ Comparison of prints, 90, 167
+
+ Compass bearings, 84
+
+ Compasses, test by the points of, 61
+
+ Copper sheeting for inking, 42;
+ for smoking, 48
+
+ Cores, 6, 76, 145
+
+ Correlation, 158
+
+ Couplets of digits, 119;
+ of A and B brothers, 172
+
+ Creases, 1, 56;
+ in infant, 57
+
+ Criminals, 149
+
+ Crosse, Dr., 192
+
+ Cylinder, revolving, 49
+
+
+ Dabs by the finger, 40, 90, 153
+
+ Darenth Asylum, 19, 197
+
+ Demography, Congress of, 163
+
+ Deserters, 149, 164
+
+ Development, 58
+
+ Digits, peculiarities of, 114
+
+ Direction of twist, 78
+
+ Divergence of ridges, 68
+
+ Drawing master, 48
+
+ Ducts, 57
+
+ Dyes, 44
+
+
+ Ear-marking the A, B sets of brothers, 172
+
+ Embryology, 58
+
+ Enclosures within ridges, 92
+
+ English, the, 17, 192
+
+ Enlargements, 51
+
+ Envelopes to rods or staples, 76
+
+ Error, law of, 19, 198;
+ "probable," 199
+
+ EVIDENTIAL VALUE, Chap. VII., 100
+
+ Evolution, 20, 60
+
+ Eyes in patterns, 143
+
+
+ Fauld, Mr., 26
+
+ Feet, prints of, 45;
+ ridges on, 57, 58
+
+ Fere, M., 197
+
+ Ferris, Major, 149
+
+ Ferro-prussiate process, 51, 53, 90
+
+ File, 63
+
+ Flexure, lines of, in palm, 56
+
+ Focus of eye, range of, 72
+
+ Folders;--inked, 42;
+ smoked, 48
+
+ Foot-paths, 107
+
+ Forgeot, Dr., 46
+
+ Forks, 91
+
+ Fraternity, 16, 171
+
+ Frequency of error, law of, 19, 198
+
+ Funnel, 36
+
+ Furrows, not followed, 82
+
+
+ G----, Sir W., 89, 97
+
+ GENERA, Chap. XIII., 198;
+ the nine chief genera, 6, 80
+
+ Glass, temporary prints on, 30;
+ etched, 47;
+ for lantern, 51
+
+ Glue, 48
+
+ Goldie, Sir G. T., 192
+
+ Granulations on rollers, 34
+
+ Greenleaf, Col. C. R., 164
+
+ Gulliver, 1
+
+ Gum, 48
+
+ Gutta-percha, 50
+
+
+ Hand, 23, 45
+
+ Harrild, Messrs., 36, 41
+
+ Hawksley, 42
+
+ Haycraft, Dr. J. B., 51
+
+ Head-length and breadth, 158
+
+ Hebrews, 18, 192, 194
+
+ Herbette, M., 168
+
+ HEREDITY, Chap. XI., 170;
+ _see also_ 16
+
+ Herschel, Sir W. J., 4, 9, 27;
+ instructions for printing, 45;
+ data for persistence, 89;
+ right fore-finger of, 95;
+ official experience, 27, 149, 153
+
+ Hindoos, 152
+
+
+ I (or Inner side), 70
+
+ Identification, 147;
+ _see_ Jezebel, 113
+
+ Idiots, 8, 19, 59, 197
+
+ Illusion, 66, 77
+
+ Indexing, power of, 14, 139, 167;
+ methods of, 131;
+ specimen of, 133;
+ search in, 166
+
+ India-rubber for roller, 40
+
+ Ink, printer's, 37;
+ for stamp, 45
+
+ Inner side, 70
+
+ Interpolation of ridges, 102, 104
+
+ Interspace, 54, 67
+
+ Interval, equally discernible, 65, 101
+
+ Islands, 92
+
+
+ Japan, 23, 26
+
+ Jews, 18, 192, 194
+
+ Jezebel, 113
+
+
+ Kensington, S., my laboratory at, 4, 35
+
+ Klaatsch, Dr. H., 60
+
+ Kollmann, Dr. A., 58
+
+
+ Labels, gummed, as for luggage, 48
+
+ Laboratory, anthropometric, 4, 35
+
+ Labourers, 59, 197
+
+ Lace, 9, 98
+
+ Ladies' hands, ridges on, 32
+
+ Language, inadequacy of, 172
+
+ Lankester, Prof. Ray, 45
+
+ Left and right, 70
+
+ Lenses, 72
+
+ Letters, alike when reversed, 71
+
+ Licked paper, 48
+
+ Linen-tester (lens), 73
+
+ Linseed oil, 37
+
+ Litharge, 35
+
+ Lithography, 43
+
+ Loops, 7, 75, 78;
+ predominance of, 101;
+ relationships of, 184;
+ on thumbs, 200;
+ typical shape of, 207
+
+ Lying Bob, 27
+
+ Lyon, 155
+
+
+ Mammalia, 60
+
+ Marseille, 155
+
+ Measurement of patterns, 82
+
+ Memoirs by the author, 3
+
+ METHODS OF INDEXING, Chap. IX., 131
+
+ METHODS OF PRINTING, Chap. III., 30
+
+ Mica, 47, 51
+
+ Minutiae, 54;
+ ambiguities in, 91, 99
+
+ Monkey pattern, 18, 54, 77;
+ ridges on tail, 60;
+ Purkenje on, 86, 88;
+ stuffed, 97
+
+ Morgue, 148;
+ _see_ Jezebel, 113
+
+ Mould for casting rollers, 40
+
+ Mountain ranges, 32
+
+ Mucilage, 48
+
+ Mummies, ridges still visible, 97
+
+
+ Nail-marks, 25, 67
+
+ Natural selection, 20, 210
+
+ Negro, 18, 192, 195;
+ cheiromancy, 26
+
+ Ngeu-yang-siun, 25
+
+ Notes, musical, 63
+
+
+ Oil, oxidisation of, 34, 43;
+ for ink, 37
+
+ Orientation, 68
+
+ Outer side, 70
+
+ Outlines, 6, 69;
+ followed with a point, 74
+
+ Overtones, 63
+
+
+ Pacinian bodies, 60
+
+ Pad for stamp, 32, 44;
+ of paper, 38
+
+ Palm of the hand, 54, 88, 113
+
+ Palmistry, 1, 26;
+ _see_ Cheiromancy, 56
+
+ Panmixia, 20, 209
+
+ Pantagraph, 52
+
+ Paper in pads, 38;
+ _see_ Cards
+
+ Papillae, 60
+
+ Paraffin, 36
+
+ Paris, 155
+
+ Passports, 15, 149
+
+ Paste, 48
+
+ PATTERNS: THEIR OUTLINES AND CORES, Chap. V., 64;
+ _see also_ 2, 54, 170;
+ number of easily distinguishable patterns, 100;
+ standard, 74, 80;
+ ditto C. set, 177;
+ percentage frequency of, 115
+
+ PECULIARITIES OF THE DIGITS, Chap. VIII., 114
+
+ PERSISTENCE, Chap. VI., 89
+
+ PERSONAL IDENTIFICATION, Chap. X., 147;
+ _see also_ 16, 113;
+ lecture on, 2
+
+ Photographers, 147;
+ photographs, 3, 51
+
+ Plots, triangular, 67, 82
+
+ Plumbago, 49
+
+ Pocket printing apparatus, 40
+
+ Points of reference, 90
+
+ Poole, Mr. S. L., 25
+
+ Pores, 57
+
+ PREVIOUS USE OF FINGER PRINTS, Chap. II., 22
+
+ Printing, the methods of, 30;
+ printer's ink, 35
+
+ Prism, 52, 104
+
+ Purkenje's _Commentatio_, 84;
+ _see also_ 8, 64, 67;
+ on slope of loop, 119
+
+
+ RACES AND CLASSES, Chap. XII., 192;
+ _see also_ 17
+
+ Radial, 70
+
+ Random events, 172;
+ _see also_ 126
+
+ Razor, prints on, 30
+
+ Reconstruction of hidden ridges, 102
+
+ Reeves and Co., 35
+
+ Registration in India, 28, 151
+
+ Regression, 21, 171
+
+ Relationship in fingers, 12, 123;
+ fraternal, 171, 175;
+ in twins, 185;
+ filial, 190;
+ ditto of like-patterned parents, 187;
+ in patterns, 178;
+ paternal and maternal, 190
+
+ Reticulation, 108
+
+ Reversals, 43, 71
+
+ RIDGES AND THEIR USES, Chap. IV., 54;
+ _see also_ low relief of ridges, 32;
+ counting them, 73;
+ ridge-interval, 62:--measurement by, 83;
+ squares of one in the side, 102;
+ of six, 103;
+ of five, 107, 111
+
+ Right and left, 70
+
+ Robinson, Dr. Louis, 45
+
+ Rods, 76
+
+ Rolled prints, 7, 39, 68
+
+ Roller, 36;
+ small, 40
+
+ Royal Institution, 2
+
+
+ Sand, ridges on, 54
+
+ Scars, 59, 97
+
+ Seal, 22;
+ sealing-wax casts, 50
+
+ Seamstresses, 59
+
+ Selection, 20, 209
+
+ Shrimps, 210
+
+ _Signalements_, 156
+
+ Size (glue), 48, 49
+
+ Skin disease on fingers, 122
+
+ Slab, 4, 35, 41
+
+ Slopes, 136;
+ on fore-finger, 118
+
+ Smart, Major Charles, 164
+
+ Smoke-prints, 47
+
+ Snow on mountain ranges, 32
+
+ Soda (washing), 36, 41
+
+ Spielman, Isidore, Mr., 192
+
+ Spirals, 74
+
+ Sports, 20, 211
+
+ Squares (interpolations), 10, 101
+
+ Standard patterns, 74, 76;
+ the C. set, 177
+
+ Staples, 76, 83
+
+ Stereoscope, 9
+
+ Students, in Art and Science, 197
+
+ Surnames, Hindoo and Chinese, 14, 152
+
+ Swift, Dean, 1
+
+ Symbols for patterns, 144
+
+ Systems of ridges on palm, 54
+
+
+ Tables, _see_ list of, p. xiii.
+
+ Tabor, Mr., 26
+
+ Tabulations, 179
+
+ Tang dynasty, 25
+
+ Tattoo marks, 97
+
+ Taylor, T. Meadows, Mr., 24
+
+ Teeth, 166
+
+ Tests of calculated Randoms, 173;
+ of classification, 179
+
+ Thompson, Gilbert, Mr., 27, 44
+
+ Thrills, their relation to notes, 63
+
+ Thumb, loops on, 200;
+ ball of, 96, 98
+
+ _Tipsahi_, 24
+
+ Titchener, E. B., Mr., 62
+
+ Title-page, prints on, 8, 58, 73;
+ index-number to them, 135
+
+ Toes, 57
+
+ Tools, callosities caused by, 59
+
+ Transitional patterns, 79, 143, 178
+
+ Triangular plots, 67, 86, 87
+
+ Turpentine, 36
+
+ Twins, 17, 167, 185
+
+ Twist, direction of, 78
+
+ Type, 19, 198
+
+
+ Ulnar, 70
+
+ United States, system used in, 15, 164
+
+
+ Variation, 20, 211
+
+ Varnish, prints on when undried, 50
+
+ Velvet, 63
+
+
+ Wall-paper, 66
+
+ Water colours, 44
+
+ Wax;--sealing, 50;
+ dentist's, 50
+
+ Weldon, Prof., 210
+
+ Welsh, the, 17, 192
+
+ Wen-teh, the Empress, 25
+
+ Whitening, 49
+
+ Whorls, 7, 75, 78
+
+ Wundt, Professor, laboratory at Leipzig, 62
+
+
+THE END
+
+
+_Printed by_ R. & R. CLARK, _Edinburgh_.
+
+
+
+
+FOOTNOTES:
+
+[1] _Der Tastapparat der Hand der menschlichen Rassen und der Affen._ Dr.
+Arthur Kollmann. Leopold Voss, Leipzig, 1883. He has also published a more
+recent memoir.
+
+[2] "Morphologie der Tastballen der Saugethiere," _Jahrbuch_, xiv. p. 407.
+Leipzig, 1888.
+
+[3] _Ann. Sc. Nat._, 5th series, vol. ix. 1868.
+
+[4] The Latin is obscure. "Mira vallecularum tangentium in interna parte
+manus pedisque ... dispositio flexuraque attentionem ... in se trahit."
+There are three ways of translating "tangentium," and none of them makes
+good sense. In the index of prints he uses the phrase "vallecularum
+tactui." It would seem that he looked upon the furrows, and not the
+ridges, as the special seat of touch.
+
+[5] The results arrived at by M. Fere in a Memoir (_Comptes Rendus, Soc.
+Biologie_, July 2, 1891; Masson, 120 Boulevard St. Germain, Paris) may be
+collated with mine. The Memoir is partly a review of my paper in the
+_Phil. Trans._, and contains many observations of his own. His data are
+derived from epileptics and others mentally affected. He has, by the way,
+curiously misinterpreted my views about symmetry.
+
+
+
+
+Transcriber's Notes:
+
+Passages in italics are indicated by _italics_.
+
+Superscripted characters are indicated by {superscript}.
+
+Subscripted characters are indicated by =subscript=.
+
+Characters in smaller font are indicated by ~small~.
+
+Punctuation has been corrected without note.
+
+
+
+
+
+
+End of the Project Gutenberg EBook of Finger Prints, by Francis Galton
+
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