148 THE SENSE OF TOUCH IN ANIMALS 



arches, and the fourth and fifth digits have arches where the 

 second and third digits have whorls. The hand is much more 

 complex in pattern on the palmar portion than the plantar, 

 which is singularly simple in pattern. 



In the hand of man arches are found much less frequently 

 than loops and whorls. Dr. Galton examined five thousand 

 digits and found that 6-5 per cent, had arches, 67*5 loops, and 

 26*0 whorls, on the terminal phalanges. The palmar surface shows 

 three groups of arches at the bases of the digits, but these are 

 small and unimportant, and one or two small areas of loops, but 

 with these exceptions, it is extremely simple in pattern, showing 

 few departures from the transverse, longitudinal, and oblique 

 arrangements. The foot of man normally presents whorls and 

 loops on the terminal phalanges, but when these become distorted 

 by pressure, arches often take their place. The arched arrange- 

 ment of the ridges of the fifth digit, given in the drawing, agrees 

 with the hmited function of this digit. The hallux is far the 

 most important of the digits as to function and presents much 

 more comphcated patterns of whorls, loops, or arches in different 

 individuals. The plantar surface, except on the ball of the hallux, 

 is exceedingly simple, and more so than any other palm or sole 

 examined except the palm of the Gibbon and the sole of the 

 Chimpanzee. 



It would appear from the foregoing facts, that loops and whorls 

 are higher developments of arches, and this view of them throws 

 some Ught on the functions of the papillary ridges. If there be 

 any meaning in the patterns of which arches, loops, and whorls 

 are the highest forms, there must be more reason for the group- 

 ing of the ridges on the palm, sole, and digits, than would be 

 suppHed by the purely mechanical conditions involved in pre- 

 hension. The complexity of the patterns which marks this 

 series of hands and feet, shows that some other factor than 

 adaptation to prehension is concerned in the development of 

 the ridges. Dr. Hepburn says that " frictional sensibihty or 

 discriminating power do not account for the arrangement of the 

 papillary ridges and the patterns produced." But the arches, 

 loops, and whorls are clearly associated with an increasing acute- 



