TOUCH. 33.0 



acutely sensible in every point: hence, we may 

 infer that it contains the terminations of all the 

 nervous filaments distributed to this organ, which 

 are here found to be divided to an extreme degree 

 of minuteness. 



When examined with the microscope, this ex- 

 ternal surface presents a great number of minute 

 projecting filaments. Malpighi first discovered 

 this structure in the foot of a pig ; and he gave 

 these prominences the name of papillce. The ulti- 

 mate ramifications of the nerves of touch have 

 been distinctly traced by Breschet* into the sub- 

 stance of the papillae, where they terminate by 

 forming arches at the extremities of each of these 

 processes. We may therefore consider these papillae, 

 of which the assemblage has been termed the 

 corpus papillare, as the principal and immediate 

 organ of touch. This structure is particularly 

 conspicuous on those parts of the skin which are 

 more especially appropriated to this sense, such as 

 the tips of the fingers, the tongue, and the lips ; in 

 other parts of the surface, which are endowed with 

 less sensibility, the papillae are scarcely visible, 

 even with the aid of the microscope. 



The surface of the corium is exquisitely sensible 

 to all irritations, whether proceeding from the con- 

 tact of foreign bodies, or from the impression of 

 atmospheric air. This extreme sensibility of the 

 corium would be a source of constant torment, were 

 it not defended by the cuticle, which is unprovided 

 with either blood-vessels or nerves, and is, there- 

 fore, wholly insensible. For the same reason, also, 



* Recherches sur la structure de la peau. Paris, 183.5. 



