THE PHYSIOLOGY OF THE SENSE OF TOUCH 153 



possibility, tend to prevent slipping in walking, and only very 

 rarely in prehension, when a spherical object is grasped. But 

 when this elHptical pattern is regarded as a means of presenting 

 as many as possible of these dehcate tactile structures to any 

 opposing surface which requires discrimination, it is seen that 

 there is a meaning in the arrangement. Again, in the hand 

 and foot of the Kmkajou, Figs. 9 and 10, the terminal phalanges 

 present concentric ridges under the cover of the long-pointed 

 nails, a position in which prevention of shpping is necessarily 

 excluded, but which affords a dchcately, sensitive area on that 

 part of the pulp which may often be called upon to discriminate 

 in a very important manner, as to different surfaces with which 

 this active arboreal animal is concerned. In Figs. 12, 13, the 

 Hedgehog shows a similar rudimentary arrangement of ridges 

 on three digits of the hand, and three (D. 2, 3, 4) of the foot in 

 situations where any connection with shpping is excluded. The 

 remarkably modified hand and foot of the Slow Loris {Nycticebus 

 tardi^radus), Figs. 17, 18, is not less opposed to the friction- 

 theory of Miss Whipple when the pads and their patterns are 

 considered. The extreme tips of the digits in hand and foot 

 are furnished with a radiating arrangement of ridges, such as 

 is illustrated on Fig. 19. The ridges of this area, of which a 

 small portion in the centre is bare, are well calculated to expose 

 a very sensitive surface to any object, but for preventing shpping 

 they would be obviously useless. The tip of the singular second 

 digit of the hind foot is covered with a highly developed whorl- 

 hke pattern under the cover of the long, curved nail, where 

 no opportunity of preventing shpping is possible. All the 

 palmar and plantar surface of this creature, when quite fresh, 

 is of a remarkable softness, and is very moist. The latter 

 quahty is of great use in assisting prehension in its deliberate 

 slow movements along the branches of trees, but the soft, moist 

 character of the skin is altogether opposed to the theory that 

 the ridges, by their comphcated patterns, can prevent slipping. 

 Of course if such a skin be examined only when hardened in 

 alcohol, this peculiar quahty of moisture and softness, which 

 it shares to some extent with galago lemur and certain Monkeys, 



