автордың кітабын онлайн тегін оқу  Finger Prints

Francis Galton

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.

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.

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.

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.

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.

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.

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 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°, and complete identity as 100°. 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° division of the scale; so the results, if noted at all, are subject to grave doubt.

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.

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.

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.

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.

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.

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.

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.

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.

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 1¾ inch long, and ½ or ¾ 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 × 2½ × ¼ 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.

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.)

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.

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.

“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.”

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.

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.

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 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 papillæ 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.

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 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.

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.

Every now and then a closer inspection is wanted; for which purpose a doublet of ½-inch focus, standing on three slim legs, answers well.

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 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 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 evidence that the minutiæ 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.

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 minutiæ 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 13 gives impressions taken from the fingers of a child of 2½ 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.

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 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 minutiæ 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.

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.

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.

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.

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 2⁴, 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 2⁸ (= 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 minutiæ, is less than 1 to 2²⁴ × 2⁴ × 2⁸, or 1 to 2³⁶, 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.

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.

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° to 37°, 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° and 52°, as against 24°, 27°, 39° and 23°). 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.

41

i l l

i l l

w l

l l

Consequently an index-heading will be of the form—

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.

It may be that every one of the 4² × 3⁸, 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.

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.

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.

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 × 3 × 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:—

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.

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.

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.

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 × 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.

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.he 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° and “Utmost possibilities” as 100°.

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.

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.

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.

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.

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.

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 minutiæ, are practically independent of the pattern.

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.

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.

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:—

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.

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.

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.

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.

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.

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:—

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.

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.

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.

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.

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—

In other respects the difference of merit between the three methods is somewhat greater, as is succinctly indicated by the next table.

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 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.

The frequency with which 1, 2, 3, 4, etc., sets were found to fall under the same index-heading, is shown in Table XVIII.

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.

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 × 19, 68 × 61, 27 × 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.

The ridges are said to be first discernible in the fourth month of fœtal 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 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.

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).

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).

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).

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.

“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).