60 



KNOWLEDGE 



[Maech 1, 1901. 



FINGER-PRINTS AS EVIDENCES OF PERSONAL 

 IDENTITY. 



By E. Lydekker. 



In the gradual and imperceptible transition from child- 

 hood to old age almost all parts of the human frame 

 arc subject to a certain amount of alteration, either in 

 form or in structure, so tliat it is matter of extreme 

 difficulty to find any one feature by which an individual 

 may be distinguished with absolute certainty from 

 among all his fellow men. A remarkable exception to 

 this tendency to change is, however, exhibited by the 

 minute ridges and grooves on the balls of the fingers, 

 which, as explained in the article on " Monkey Hand- 

 Priuts," aic airanged in a number of minute concentric 

 lines forming characteristic patterns. In all monkeys, 

 with the excejjtion of some of the man-like apes, the 

 patterns formed by these papillary ridges, as they are 

 termed, are of a comparatively simple type. The 

 patterns of monkev finger-tips are indeed arranged in 

 simple flexures, which come under the denomination 

 either of " loops " or " arches," according to the classifi- 

 cation employed in the deciphering of human finger- 

 prints. Such a ''loop" is shown in Fig. 1, which 



FiG. 1. — Impression of Middle Huiiian Finger, ilisplaying tlie looped 

 arrangement of the iiapillary ridges. 



represents the impression of the middle finger of a 

 human hand. In an "arch " the flexure is still simpler, 

 and does not exhibit that marked inclination to one side 

 or the other which forms such a characteristic feature 

 in loops. 



In a large number of human fingers a still more 

 complex type of flexure is observable in the ridges, which 



Fig. 2. — Impression of Fore, Middle, and King Fingers of a Eiglit 

 Human Hand. 



assume a kind of vortex arrangement around a central 

 nucleus. This type is denominated a " whorl," and is 

 beautifully displayed in Fig. 2, which shows the prints 

 made by the fore, middle, and ring fingers of a right 

 human hand. Still more complicated patterns may be 

 produced by the mingling of two whorls, or of a whorl 

 and a loop, or a whoi'l and arch in the same finger; such 

 types being designated as " composites." Whorls and 



composites being obvioiisly more complex than loops and 

 arches, it is interesting to note that they are vmknown 

 in ordinary monkeys; and the gradual inogressiou in 

 complexity of pattern from these latter through the 

 man-like apes to man himself is just what would have 

 been expected to occur if the doctrine of evolution be 

 true. It has not yet been ascertained whether the 

 presence of arches and loops is more common in the 

 finger-tips of the lower races of mankind, while whorls 

 and composites are relatively more numerous among 

 nations of higher cultivation, but it is possible that this 

 may eventually prove to be the case. As the result of 

 the examination of the finger-tip impressions of a very 

 large number of Europeans and natives of India, it 

 appears that about five per cent, come under the denomi- 

 nation of arches, while sixty per cent, are loops, and 

 thirty-five per cent, whorls and composites; the pro- 

 portion of each varying considerably in the several digits. 

 For the purposes of forming a classification of finger- 

 prints, arches, being so few, may be reckoned as loops, 

 while composites may be included in whorls, thus giving 

 only two types to deal with. 



But before going further a few words are advisable 

 as to the manner in which finger-prints are taken. The 

 fingers are first pressed on a plate of tin which has been 

 evenly and thinly coated with printing ink, and may be 

 then pressed on suitable paper in such a manner as may 

 be thought desirable, when, if due precautions to avoid 

 smudging are taken, clear prints similar to the originals 

 from which the accompanying figures were reproduced 

 will be obtained. When the tips of the fingers are 

 merely pressed on the paper without any other move- 

 ment, the print is termed a plain one, as in Figs. 1 and 

 2 ; and it is manifest that when (as in the case of the 

 latter) the impression of three or more figures is taken 

 simultaneousl)^ it must be of this nature. But such a 

 print displays only the central portion of the pattern 

 of each finger ; and in order to obtain the pattern of a 

 laiger area of the finger-tip recourse is had to another 

 plan. To take a rolled impression, as it is called, one 

 finger only is inked at a time, and when coated with ink 

 is laid on the ))aper in such a position that the nail is in a 

 vertical plane, after which it is rolled on the paper across 

 the ball till the nail is again vertical. Two complete 

 series of such rolled impressions are exhibited in Figs. 

 A and B. It will be seen that they are taken in the 

 natural order, commencing with the right hand, and 

 passing from the thumb to the little finger ; and then 

 repeating the process with the left hand, the impressions 

 from which are placed below those of the corresponding 

 digits of the right hand. Of course such impressions 

 are always taken in the presence of a responsible 

 officer ; but to prevent the possibility of fraud, " plain " 

 impressions of the fore, middle, and ring fingers of each 

 hand are taken at the same time on the same sheet as 

 the " rolled " impression. As an additional precaution, 

 the three fingers in question are thrust through a frame 

 having three apertures before they are inked, and the 

 impression is taken while they are thus fixed. The three 

 plain impressions shown in Fig. 2 are those of the three 

 central fingers of the right hand of the individual marked 

 B (see figures), and they will be seen to correspond 

 exactly with the middle portions of the rolled impres- 

 sion. Such correspondence is quite sufficient to indicate 

 that the rolled impressions have been taken in their 

 proper sequence and belong to the same individual. 



For the purpose of identifying individuals by means of 

 their rolled finger-joints, arranged in the foregoing order, 



