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.