TACTILE CORPUSCLES 



465 



The situation of these corpuscles, beneath the true skin instead of 

 in its substance, shows that they can not properly be considered as 

 tactile corpuscles, a name which is applied to other structures found in 

 the papillae of the corium ; and it is impossible to assign to them any 

 special use connected with sensation, such as the 

 appreciation of temperature, pressure or weight. 

 All that can be said in regard to them is that they 

 constitute one of the several modes of termination 

 of sensory nerves. 



Tactile Corpuscles. The name tactile corpuscles 

 implies that these bodies are connected with the sense 

 of touch ; and this view is sustained by the fact that 

 they are found almost exclusively in parts endowed 

 in a marked degree with tactile 

 sensibility. They are sometimes 

 called the corpuscles of Meissner 

 and Wagner, after the anatomists 

 by whom they were first described. 

 The true tactile corpuscles are 

 Fig. ^.-Longitudi- found in greatest number on the 

 nai section of a corpuscle of pa lmar surfaces of the hands and 



Vater (Sappey). 



fingers and the plantar surfaces of 



I , base of the corpuscle ; 



2, apex; 3, 3, substance of the feet and toes. They exist, 



the corpuscle, in layers; j - th ^ th b fe f 



4, 4, nerve penetrating the 



corpuscle; 5, cavity of the the hands and feet, the nipples and 



nrw*wfaich' hasfTost its a ^ ew on tne anterior surface of the 

 medullary substance and forearm. The largest papillae of 



sheath ; 8, termination of , , . ,. , -111 



the nerve; 9, granular sub- the skin are found on the hands, 

 stance continuous with the f ee t an d nipples, where the tactile 



nerve 



corpuscles are most abundant, and Davidoff). 

 Corpuscles do not exist in all papillae, and they are , upper portion, in 



r . which only the epi- 



found chiefly in those called compound. In an area a theiiai ceils are repre- 



Fig. 104. Tactile 

 (Bohm 



little more than ^ of an inch square (2.2 millimeters 



square), on the third phalanx of the index-finger, the epithelial ceils; c, 



Meissner counted four hundred papillae, in one hundred 



and eight of which he found tactile corpuscles, or about one in four. 



In an equal area on the second phalanx, he found forty corpuscles ; on 



the first phalanx, fifteen ; eight on the skin of the hypothenar emi- 



nence ; thirty-four on the plantar surface of the ungual phalanx of the 



great toe ; and seven or eight in the skin on the middle of the sole of 



the foot. In the skin of the forearm the corpuscles are very rare. 



The tactile corpuscles usually occupy special papillae that are not 



2H 



