Hepburn — The Papillary Ridges on the Hands and Feet of Monl'eys and Men. 527 



Galton, in his work on " Finger-Prints," already referred to, suggests that tlie 

 papillary ridges may be of use in raising the mouths of sweat-ducts, and in 

 assisting the sense of touch. Even if both of these suggestions be accepted, it is 

 not clear why, in certain places, the ridges should assume the form of definite 

 designs. It is true that the touch-bodies which are located in the papillary ridges 

 are very numerous, both in the palm of the hand and sole of the foot ; neverthe- 

 less, touch-bodies are fairly plentiful in many other regions of the skin which are 

 not associated with papillary ridges, arranged in patterns. Indeed, if we compare 

 the sole of man's foot with the palm of his hand as regards sensibility, we shall 

 find* that the sole is much less sensitive than the palm, although in both the 

 papillary ridges are equally numerous and distinct. Again, such regions as the 

 tip of the nose, the red part of the lips, and the dorsum of the third phalanges, 

 are from two to three times as sensitive as the plantar surface of the great toe, and 

 yet the former regions are not distinguished by papillary ridges, whereas the 

 latter is so characterized. Further, as regards the palm itself, Kollmannf states 

 that touch-bodies are most numerous on the tips of the fingers ; somewhat 

 diminished in numbers on the three eminences on the palm which lie above the 

 clefts between the fingers ; then still more reduced in numbers on the ball of the 

 thumb and ball of the little finger; and, finally, much less numerous on other 

 parts of the palm. Now, it is necessary to note two points in connexion with this 

 statement — First, that the papillary ridges do not dwindle either in numbers or in 

 distinctness, although the touch-bodies become reduced in numbers ; and second, in 

 each of the areas to which Kollmann directs special attention, viz. the tips of the 

 digits and the various palmar eminences, the papillary ridges are so arranged as 

 to form patterns or designs. It seems to me, therefore, that in certain regions 

 great sensibility may be associated with the presence of papillary ridges, but that 

 we cannot assume that the presence of papillary ridges is synonymous with 

 increased sensibility. Of course I fully recognize the fact that the greater 

 sensibility of such an area as the tip of the nose may be accounted for by a 

 thinner cuticular covering ; but this only shows that acute sensibility is not 

 dependent on papillary ridges. Again, Professor Cunningham has reminded me 

 that papillary ridges, like any papillary surface, have "a kind of frictional 

 sensibility — a discriminating power — a capability of distinguishing the texture 

 and quality of another surface over which they may be rubbed." But while 

 granting this discriminating sensibility, and recognizing its value to an ape 

 swinging from branch to branch, as well as the perfection to which it may attain 

 by training, as in the hand of a blind man, yet I do not think that it accounts for 

 the arrangement of the papillary ridges and the production of definite patterns. 



* Textbook of Human Physiology. Landois and Stirling, 1886, vol. 2. 

 t Kollmann, quoted by Landois and Stirling. Ibid., p. 1153. 



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