The Patterns in Thumb and Finger Marks. [Nov. 27, 



The origin of the patterns was shown to be due to the existence of 

 the n,ul, which interfered with the horizontal course of the papillary 

 ridges, and caused those near the tip to run in arches, leaving an 

 interspace between them and the horizontal ridges below. This 

 interspace was tilled with various scrolls which formed the patterns. 

 The points or point at which the ridges diverged to enclose the inter- 

 space were cardinal points in the classification. It was shown that 

 there were in all only nine possible ways in which the main features 

 of the inclosure of the interspace could be effected. In addition to 

 the 9 classes there was a primary form, occurring in about 3 per cent, 

 of ail the cases, in which the interspace was not clearly marked, and 

 from this primary form all the other patterns were evolved. The 

 forms of the patterns were easily traced in individual cases by follow- 

 ing the two pair of divergent ridges, or the one pair if there was only 

 one pair, to their terminations, pursuing the innermost branch when- 

 ever the ridge bifurcated, and continuing on an adjacent ridge when- 

 ever the one that was being followed happened to come to an end. 

 25 of the principal patterns were submitted, and a few varieties 

 of some of them, making a total of 40. They are by no means equally 

 frequent. 



The data as to the permanence of the patterns and of the ridges 

 that compose them were supplie.d to the author by Sir W. J. Herschel, 

 who, when in the Indian Civil Service, introduced in his district the 

 practice of impressing finger marks as a check against personation. 

 Impressions made by one or two fingers of 4 adults about 30 years 

 ago, and of a boy 9 years ago, are compared with their present 

 impressions. There are eight pairs of impressions altogether, and it is 

 shown that out of a total of 296 definite points of comparison 

 which they afford, namely the places where ridges cease, not one failed 

 to exist in both impressions of the same set. In making this com- 

 parison, no regard was paid to the manner in which the several ridges 

 appear to come to an end, whether abruptly or by junction with 

 another ridge. The reas m was partly, because the neck where junc- 

 tion takes place is often low and may fail to leave a mark in one of 

 the impressions. 



Lastly, the various patterns were shown to be central typical forms 

 from which individual varieties departed to various degrees with a 

 diminishing frequency in each mere distant degree, whose rate was in 

 fair accordance with the theoretical law of frequency of error. Con- 

 sequently, wide departures were extremely rare, and the several 

 patterns corresponded to the centres of isolated groups, whose isola- 

 tion was not absolutely complete, nor was it due to any rounding off 

 by defined boundaries, but to the great rarity of transitional cases. 

 This condition was brought about by internal causes only, without 

 the least help from natural selection, whether sexual or other. The 



