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.