426 



STRUCTURF. OF THE SKIN 



mic layers, as seen in fig. 113.* The nerves are here seen 

 passing up into the papillas through the dermis ; the vascular 

 branches which accompany them are not here represented. 

 The papilla first gets a neurilematic covering fi'om the upper 

 surface of the derm, and is there furnished with several layers 

 Fig. 113.f of the epidermic horny matter, which 



cover it like a hood. This horny cov- 

 ering is particularly thick at the heel, 

 and serves to protect the papillae by the 

 deadening of shocks, and resisting the 

 pressure of the weight of the body. 

 The papillae are most numerous on the 

 palms of the hands and soles of the 

 feet, but are also scattered over other 

 parts of the body .J 



Of the Sudoriferous or Diapnogenous 

 Apparatus. 



— This consists of a gland, see fig. 112, p. 423, placed in the 

 substance of the dermis, near its inner surface, into which a 

 great many capillary vessels run, and of a spiral duct which 

 runs up through the horny layers and opens obliquely through 

 the outer epidermic crust by a slight depression or pore, on the 



* According to these writers the nerves, as they pass up from the under sur- 

 face of the skin, becomes soft, flexuous, and capillary, and as they enter the 

 villi on the top of the papilli, lose their neurilema, and are expanded in the 

 form of pulp. They look upon the changes which the nerve undergoes, and 

 upon the derm, villi, and epidermic covering, as so many parts necessary to 

 constitute the perfect organ of touch : thereby assimilating it to the more com- 

 plicated organs of sight and hearing. — Loc. cit. p. 15, et seq. — 



f Fig. 113, represents the apparatus which constitutes the organ of touch in 

 man. a, Nerve entering into the dermis, where it becomes capillary, b, Its 

 entry into the papilla, c, Neurilema furnished by the dermis, d, Proper envel- 

 op of the nerve, e, Corneus layers more or less thick, which form the organ of 

 protection to the nerve. The capillary blood-vessels which pass up with the 

 nerves are not here shown. 



X From their observations upon the papillee of the whale, these anatomists 

 are disposed to believe that the nervous fibrils terminate at the top of the villi, 

 by loops with one another, as Prevost and Dumas have shown them to do in 

 other parts of the body. — 



