Dactylography

Kew Micrometer.

In making measurements of exhibits, the Kew micrometer devised by Sir Joseph Hooker is of much service. It is figured here, and has the useful quality of rendering measurements at the same time in both the English and decimal systems.

For the method of encircling suspect smudges, either before or after enlargement, and measuring from one fixed centre by the Kew micrometer or ordinary compasses, I have devised a disc of glass such as is used in microscope slides, and about the size of half-a-crown. In the centre is a conical pit into which one leg of the compass rests. Precise centring is thus obtained without the slightest risk of damaging the photographic or other exhibit by the sharp point of the compasses, which have, at the same time, free swing. These were prepared for me by Mr. Franks, optician, Stoke-on-Trent, and cost very little.

Glass Disc Centred (enlarged).

In all measurements close to a fork or junction, as in the crook of the letter Y, care must be taken in counting the lines below or above the fork. Ambiguity readily arises, with a train of resulting discrepancies. Other ambiguities also occur which require mention in a word or two. In deciphering an ancient manuscript blurred, mouldy, mayhap worm-eaten, doubts may arise as to which of two or three possible words or letters may have been intended. One looks for some rationality in the author’s writing, but in finger-prints there can be no such help. In manuscripts the problem may not directly be as to a word, but only as to a letter, but that single letter, read differently, may change the tenor of a passage. Is

to be read as C or as G or as O? Is

to be read as E or as B? So Fork is liable to be read as Pork.

Now, a very similar difficulty frequently occurs in reading a blurred finger-print, and such evidence should be scrutinized with the greatest vigilance, and all really doubtful cases should be discarded as useless in evidence. While the obscurity is sometimes merely due to defective printing, there are several patterns of frequent occurrence which are liable to be read variably. This was discussed at some length in chapter iii. of the Guide. There is a tendency so to view blots or blurs in such a case, that the cloudy spots become a weasel or even a whale. In Japan there are artists’ wine-parties, where a common game is to make an accidental splash of ink or colour, which is passed on to the next guest, who in turn converts it by one or more strokes of the brush into a figure of some character. Some years ago, I gave to a young men’s meeting a lecture on Ghosts, in which I showed a collection of ink-splashes produced without design, some of which were quite strikingly artistic in their suggestive impressionism. Hence the importance of clear printing, vigilant scrutiny of exhibits to be compared, and the attention of a well-informed judge and intelligent jury.

In certain circumstances, when a suspected person has been arrested abroad or at a distance, it may be desirable to compare his fresh finger-prints broadly with that of some well-known criminal whose register has been long in the hands of the police. This want led me to suggest, in 1905, that photo-telegraphy, in one of its forms, might be brought into use. Many improvements have been made since then, and it is now, I think, quite feasible to secure and transmit to a great distance outline lineations quite good enough for use at a preliminary enquiry, previous to a remand or committal.

CHAPTER VI

PERSISTENCE OF PATTERNS

A human finger, in ordinary circumstances, may preserve, unimpaired, not only its general pattern of lineations, sometimes very intricate, during its owner’s lifetime, but the minutest details also may be discerned after thirty or forty years, quite unchanged as elements of a pattern, and very likely for a longer period, though scientific observation has not extended much beyond that limit. Long immersion, after death, in water, till the skin is quite sodden, does not readily destroy, does not even greatly obscure, the lineations for the purpose of comparison with earlier printed records of them, and one can still read into finger-print type, so to speak, the lineations of an Egyptian mummy.

When first I ventured to call the attention of the scientific world to the patterns of finger-prints in 1879 or 1880, I suggested that the ancient mummies of Egypt might possibly be found to have retained those features sufficiently to be studied. I had no opportunity of obtaining access to such remains in order to test the point, but on returning to England I found that anticipation to be amply justified, as anyone may verify by a visit to the British Museum. The skin of a mummy is contracted, hard, and wrinkled, but one may trace the lineations through all their loops, joinings, ramifications and whorls, with great distinctness. So that it follows, did an Egyptian register of finger-prints exist, we might unearth the names and titles or deeds of some of those men who lived several thousands of years ago.

There is nothing, so far as has yet been observed, to mark their race out as essentially different from our own, nor do any ancient finger-prints look unlike those of present-day people’s.

The ridges on toes and fingers are visible in children born prematurely, even at a very early period, as I have observed in the practice of my profession, and as soon as the lineations are at all discernible they are of human type. So far as has yet been observed, we do not find that the growing human embryo repeats a history of finger-patterns, beginning at an earlier and lowlier biological stage, as is sometimes contended to be the case in regard to some other organic structures undergoing development.

The efforts I first made to investigate the problem of permanence were chiefly directed to the earlier periods of life, as presenting the greatest likelihood of variation in patterns during rapid growth. A large number of Japanese children, and also some thirty-five or more children of European parentage, in ages from five to ten, were minutely examined time after time during a period of two years – some of them again at longer intervals – without a single variation being detected. The lines and patterns in the fingers of growing children broaden out as the infant grows, but the ideal form – so to speak – of the pattern itself, retains full sway. To grasp this conception clearly is almost the whole science of finger-print identification.

During that period, some of those children suffered severely from scarlet fever, which, as a new disease, took a severe form in Japan, and the desquamation, or skin-peeling, was unusually severe, so that in those cases the test was a severe one. On several occasions I have called attention to the possibility of severe desquamation being followed by some change of patterns, and I still think this subject merits the attention of medical men, but no actual fact illustrating the apparent danger has yet been brought under notice. This may, however, be simply the result of a high degree of inattention to a subject which medical men do not seem to have interested themselves in until very recently. In acromegaly, a disease in which the fingers take on gigantic features, one might expect to find a very notable change of patterns, perhaps the addition of fresh lineations, but after some attempts to collect information not one single example of the kind has yet reached me.

Besides testing growing children in the manner I have stated, many Japanese medical students between the ages of twenty and thirty were made use of in this way. The ridges were carefully shaved by razors, or smoothed away by sand-paper, emery dust, or pumice stone, so that no distinct patterns could be traced. The same tests were applied to my own fingers and to those of one or two medical friends who were quite sceptical as to the continuity of the patterns. Many of the patients at the hospital, or out-door dispensary, were also induced to submit, but not a single instance of variation in the patterns was ever brought to light. My own fingerprints have not varied since that date, a period of fully thirty years. However smooth the surface had been made, the old design came up again with perfect fidelity, yielding exactly the same imprints as before, subject only to those very minor variations already described in a previous chapter, to which even engravings are subject. Up to the period of my final return to England in 1887, a period of nearly nine years, enthusiastic and vigilant observation of this point gave me complete confidence in the permanence of finger-print patterns as a basis of personal identification. With the exception of acromegaly and skin-peeling after acute fevers, I can conceive of no biological reason why changes might be anticipated in those patterns, and up to the present no evidence has reached me that even those conditions do effect pattern changes. In old age the ridges shrink somewhat, and wrinkles here and there betray the drying up of tissues, which facts are revealed in printed impressions by fine white lines, often cutting across the lineations, not unlike those which occur in box-wood engravings, where hair-like lines betray some cleavage of the wood. In such a case the value of the pattern is not affected as a proof of identity. One may go beyond that, and say that, if after a lapse of forty years or so the old pattern is now crossed by wrinkles which were not there in youth, the two prints are from the same individual.

Other observers – Sir Francis Galton, Sir William Herschel, and the police of this and other countries – have accumulated a vast store of conclusive evidence on this point.

We are now amply justified in assuming that, for all practical purposes of identification, the patterns on human fingers are, throughout life, persistent and unchangeable. Such slight and transient changes – not due to mere variations of pressure, inking, and the like, as they usually are – are no more likely to invalidate an identification than a new freckle or pimple on a man’s face would make him unrecognizable by his intimate friends.

Dr. J. G. Garson, in an article in the Daily Express of July 20th, 1905, writing on this subject, which he has carefully studied, said: —

“It is now a well ascertained fact that every person bears on his fingers as certain proof of his identity as he does on his face. The latter is, however, that part of his anatomy by which he is most readily identified by the world at large, though to his intimate friends other particulars about him may characterise him equally strongly. By means of the eye, the tout ensemble of the countenance is registered upon the mind, generally regardless of details respecting the actual form of each particular feature – in short, a person is recognized and identified by exactly the same psychological process as a printed or written word is read without first spelling it.”

It must be clear to any student of the subject that persistence of patterns must become the basis of identification in this way, and that persistence is now as firmly established as anything can be as to living creatures.

Sir Edward Henry, in his Finger-Prints, says (p. 17, 3rd edition): “Impressions being required for permanent record, their utility must, in great measure, be contingent upon the persistence through long periods of time, of the general form of the pattern and of the details of the ridges constituting it.” No such stability has yet been shown to exist in regard to any other part of the body. The bones change very greatly, not only in size, but in shape, texture, and mechanical conditions through life. Even the ordinary features and expression of a human being by no means can be said to remain uniform. One sees a friend during many short intervals, and is not finely observant of minute changes that in a decade or two amount collectively to an almost complete transformation of the man’s whole face and figure. The photographic system of identification, although serving a purpose now and then, was found, therefore, to be untrustworthy.

My revered teacher, Lord Lister, noted the slow migrations of the pigmentary particles that make the web-like patterns on a frog’s foot. I have observed similar but still slower changes in ordinary freckles on a human hand. The white spots of leucoderma – a skin-disease that used to be confused with leprosy, from which it entirely differs – are often bounded with dark borders, into which the pigment particles have migrated from the white spots. A negro’s skin sometimes becomes white where a fly-blister has been applied, as a fair-skinned person is often marked with a dark patch after a similar application. The pigment particles move to and fro like living things, though very slowly, and the marks they collectively make on a living body are not fixed and stable. Again, we have seen that the police used to record the position of wens, tumours, tattoo marks and the like. But tumours are now often removed through the line of natural creases, or wrinkles, leaving very faint traces, if any, behind.

An official in Japan had a large wen on his forehead, which disfigured him greatly. He was getting elderly, and told me, when friends brought him, that he would as soon have the wen as a scar. I got him to consent to have it removed through the natural wrinkle in the forehead, after which it left no visible trace at all.

A curious case was that of a man whose back and shoulders were adorned by a large collection of a certain kind of tumour varying from the size of a chestnut to that of a hen’s egg. They all disappeared, without the use of the knife, leaving no scar behind, and only a slight lowering and thinning of the skin.

Even scars, themselves, sometimes very unsightly ones, tone away to a large extent, till they cease to be at all conspicuous. The colour of the hair changes greatly in some people at the various stages of life. Certain diseases, too, such as malarious affections, the action of the sun, and certain employments, change the complexion in a very remarkable way.

What the pole-star used to be in navigation, fingerprint patterns are now become for all serious purposes of practical identification.

CHAPTER VII

THE SYLLABIC CLASSIFICATION OF FINGER-PRINTS

Having secured some technical knowledge of how to print, and how to read old finger-prints correctly and with confidence when they turn up again in experience, we are faced now with the problem of how to classify and arrange them for secure preservation and prompt and easy reference, whatever may be our object.

In natural history, in biological facts generally, it is not always easy to define the objects of study strictly, so as to classify them in a practical way. Dealing, however, with printed finger-patterns which are no longer living and changing things, we can hope to secure some of the advantages of a mechanical method. Verworn, in his General Physiology (p. 71) says, very justly: “The fixing of sharp limits and definitions must contain, finally, a more or less arbitrary element, [that], indeed, all limits and definitions are only psychological helps towards knowledge.” Bearing this principle in mind, then, what is the end or object we aim at in a system of finger-print classification?

The objects of identifying a person with some one who has had a name and left a history are of various kinds, as criminal, civil, military, naval, medical, legal, scientific, and insurance purposes. Now, in regard to the use of finger-prints for so many ends in view, a difficulty presents itself. It occurred to me at the outset of my studies, that if the system were to prove trustworthy and useful, even in a minor degree, immense numbers of people in civil life, in army, navy, and mercantile services, or under criminal conviction, would require to have their prints correctly classified, indexed, and arranged for easy reference. How could it be possible in so vast a collection or series of collections to find the one single record wanted? To ransack – unaided by a scientific method of classification – the register of an army containing some 500,000 soldiers would involve the search of a much larger number of cards or sheets than 500,000, according to the duration of regular service, and other possible conditions. To do this would obviously be quite as hopeless and futile a task as groping for a lost needle in a huge hay-field. The problem was to find a system which would facilitate the search in a high degree. Any mere slight assistance would still leave the essential problem unsolved. Now, we might have found in finger-prints mere variety without persistence, or mere persistence without initial variety, and in either case the study could yield little practical result. Again, mere diversity, however persistent, without some elements of underlying resemblance, would not have yielded a basis for such a methodic arrangement as was obviously required.

Much aid came to me from the first, as I have already hinted, from five years’ daily laborious experience in sorting and comparing analogous but artificial patterns in the now obsolete Paisley shawl trade, but in the case now in view colour did not come in as an aid to arrangement. This problem, moreover, was not one of those the poet derides as of mere “gold or clay,” but as I saw, it concerned itself with human lives, and was a task, indeed, that might awaken in the dullest mind a keen sense of moral responsibility in proposing its general use as a new and quite trustworthy method of criminal and other modes of identification. The expert in charge might suddenly be called upon after a little expansion of the system to prove the identity of some evil-doer out of many thousands of possible persons, or to subject a suspected person, on the evidence of a few smudgy streaks of ink or blood, to life-long servitude, or to the irremediable doom of a shameful death. In my own case, at this early stage, the mere possibility of a single serious false identification by a method as yet untried became really terrible to contemplate. After closer study, a clear path began to open through the tangled jungle.

Some familiarity with the equipment of a Far-Eastern printing-press had been afforded me while editing The Chrysanthemum, a monthly magazine published in Tokyo, and devoted to the discussion of Japanese topics of literary, scientific, or antiquarian interest. There were some hundreds of thousands of different forms of type, all classified in so convenient a way that any compositor, by running about a little more actively than would be quite compatible with the grave dignity of an English printing establishment, could soon find the character in whatever form of fount he desired. The idea suggested itself then, that analogous qualities as a basis for classification of the finger-patterns might be revealed by a closer study of Chinese. I do not know Chinese – some years’ close study has convinced me of that. However, each Chinese ideograph, for dictionary purposes, is supposed to be built up around an element called by western lexicographers its key or radical, and of these there are two hundred and twelve. You look for the radical in an unknown character, and then look for that radical in its serial place in the two hundred and twelve. It is a question then, as in finger-prints, of counting strokes, and if the strokes are alike in number in any two instances, of looking then as to how they are arranged. Two characters with the same number of pen-strokes under the same radical or key, may bear quite a different aspect.

A Chinese character is defined and limited, but a finger-print pattern often, or usually, trails off into indeterminate lineations of little value for classification purposes. Hence we seek in the latter to isolate for study the central part of the pattern, where the intricacy of the ramifications usually rises to a maximum. The space covered by the lineations that matter is not usually greater than, often not so wide as, the space occupied by the head of the Sovereign on an English postage stamp. Into this brief compass is compressed a world of significance. A courteous and intelligent young detective in Scotland Yard asked me (in 1886 or 1887, when I was advocating the adoption of finger-print identification), did I really propose to rest identification on features contained within so small a space? I answered him, in pointing to a railway map of London, to consider a net-work of junctions which I indicated, if he would not be justified in saying if that fragment, torn away from its context, were presented to him, that it was a portion of a map of London? After a little scrutiny, he admitted that was so. I had no difficulty in showing him then, that the condensed ramifications of a single finger-print within the very limited area proposed by me were much greater than that of the significant portion of the London map I had just pointed out to him.

In tracking a criminal by a single impression made by a finger, the lineations in so small a space would require to have been clearly imprinted, and to have what many finger-print patterns have not, some notable or significant characteristics about it. Then, when enlarged by photography into a picture of some thirty inches, the measurements from fixed points in the pattern should correspond with those of the person in custody, on suspicion, and the curves should be shown to concur in all their sinuosities. But, in comparing two official imprints of the ten fingers properly and clearly impressed, there should be no difficulty, the points of comparison being overwhelming.

In a possible collection of half-a-million or a million complete sets of finger-prints, can the one before me, of one Thomas Atkins, John Doe, or Richard Roe – under whatever alias – be promptly found if it is there, or, if not there, can its absence be conclusively determined? We have seen, I think, that if two such patterns are confronted, common-sense, and the use of fine measurements, will soon determine whether they be of the same original, or different. The problem, then, is to get this swift and sure confrontation effected.

This problem engaged my attention from the first, or at least not many months after I first began to attend to finger-patterns, and in 1880, when I proposed the printing and recording of the ten fingers of old criminals, I had thought out the same method now outlined in this chapter. It would be impossible to compress all the details necessary to work out the matter officially, without producing a work as large, and perhaps as expensive, as a Chinese dictionary, of which the probabilities are that one or perhaps two copies might be sold.

I laid this matter in outline before Inspector Tunbridge, in his official capacity, in 1888, and again before the War Office Committee, at which an Under-Secretary of the Home Office was present, taking diligent notes. The system now in official use – an improvement made by Sir Edward R. Henry upon Sir F. Galton’s very premature attempt (after a few years’ study in old age) seems to work practically, and therefore I have no criticism to offer, further than to suggest, that if in our system of mercantile book-keeping we had retained the use of Roman numerals, fortunes might continue to be made or lost. I cannot think, however, that our merchants would now give up the Arabic notation for the more complex and clumsy one of ancient Italy. Nor is nature likely to resume her interest in the kangaroo and its future.

Science seeks simplicity, and the Syllabic system, now familiar to every one who uses a telegraphic code, is what I proposed for finger-print registers. In this I simply followed the method of transliterating Japanese and Chinese words into syllables of the Roman alphabet, a condition originally imposed by the old Japanese language itself, in which consonants do not occur singly, but are followed by vowels. Purkinje’s first analysis of the finger-print patterns was not known to me, nor, I believe, to anyone in Europe or America, when I first wrote, although I often in those years suggested that he had probably written something on the subject. My first article in Nature, as sent up, contained a kind of analysis of patterns, with many types, named as whorls, ovals, deltas, loops, junctions, and the like. Some are referred to in the text, but the editor expressed his regret that he had not been able to insert the figures, and their lack made the references in my article obscure. We shall deal with a few of these elementary or typical figures presently. But, let us now come to the main aspect of the syllabic system, in contrast with that devised by Sir F. Galton, who looked upon it as merely ancillary to the anthropometric system of Mons. A. Bertillon, of the French police. Galton was supremely anxious to have his natural facts, his finger-print records, arranged precisely in similar parcels, so that one would not be excessively rich in records compared with its neighbour. Now, what does it matter to the keeper of records, or even to the tax-payer, whether one class of patterns is big or little? The whole absurd complexity arising now, and increasing from year to year, grows out of this essential misapprehension from the first of the vital problems of finger-print classification. Advancing a stage for the moment, let us suppose that a rich register exists, arranged on the syllabic system. A type-writer, not necessarily a very intellectual creature, or a boy-clerk, is in the room, and has the call to find A-bra-ca-da-bra. I use here for convenience only five syllables, representing one hand. The sheets or cards (sheets have been found best by experience) are not separated in bundles except as to a convenient size. It does not take long to look along the shelves till A-bra- etc., is reached, and then the cabalistic word itself. It may prove that there are some ten sheets on the register under this syllabic title. These are transmitted, all in a few moments, to the expert keeper of the records. At a glance an expert eye like his perceives that, perhaps, seven out of the ten can have no possible relation to the case now being enquired into. Of the three, one is perhaps now in prison and cannot be the suspect. Of the two remaining forms, the details of the first two fingers compared may diverge completely in many ways, as determined by counting lines, measuring curves, and so on. I am sure this would be no fancy description, from the many tests I have applied. The whole strain of the recognition lies on the expert, as the strain of the primary classification of records had lain upon him at the time they were being made. Of course, more than one expert might be needed.