434 MANIPULATION. 



other carnivora are organs of touch, and as such are endued 

 with both blood-vessels and nerves, which are distributed upon 

 a highly organized pulp, like that of the teeth. In some 

 animals, such as fish, the skin is not very vascular, whilst in 

 the mammalia, and, perhaps, in the human subject, it attains 

 the highest state of organization. The hairs which grow from 

 the skin are developed from the cuticular layer, and are 

 clothed with a horny epidermis; in those skins where the 

 sense of touch is very acute, the hairs are absent, their place 

 being supplied by highly vascular papillas, which, in some 

 instances, are covered with horny matter, in the shape of nails 

 and hoofs, or are merely invested with a delicate epithelial 

 layer, as in the case of the lips and mouth. The skin 

 performs a function in the animal economy second only in 

 importance to that of the lungs, and for the purpose is 

 suppHed with a very rich capillary net-work, and also provided 

 with two or more sets of glands, one for secreting the perspi- 

 ratory fluid, the other an unctuous or sebaceous matter, for 

 lubricating the skin itself, which last is poured out generally 

 at the roots of the hairs, hence the anatomy of the skin 

 presents to the microscopist an immense field for diligent 

 investigation. Taking the human skin as an example, we 

 should commence the study with vertical sections, made 

 through parts supplied both with hair and papillas ; the perspi- 

 ratory glands are best seen in that of the soles of the feet and 

 palms of the hand ; the sebaceous glands, on the contrary, 

 should be examined in parts about the face or chest, where 

 hairs are numerous ; these latter sections will also suflSce for 

 showing the roots of the hairs, and the hair follicles as well. 

 The capillary net-work of the true skin may be seen in 

 injected specimens when the cuticle has been removed, which 

 will often require the aid of maceration for the purpose ; if 

 the skin be that of a black man, care should be taken in the 

 removal of the cuticle, as in it may be examined the rete 

 mucosum, or last formed layer, which consists of a series of 

 minute hexagonal cells, containing pigment. The same 

 structure may be seen in the skins of animals whose hairs are 

 black; for this purpose the lips of a black kitten, when 



