OF THE SKIN IN GENERAL. 217 



that the epidermis prevents, or greatly moderates evaporation 

 in the dead body, and that those places which are deprived of 

 it, as well as the subjacent parts, become dry with great ra- 

 pidity. The epidermis, however, permits those matters to pass 

 which the skin absorbs during life, and certainly those it ex- 

 cretes. But what is more astonishing, is, that in the observa- 

 tions of which we have just spoken, no one has been able to 

 perceive even the openings of the epidermis, through which 

 the hairs pass, those which correspond to the sebaceous folli- 

 cles, nor even those which had been made in it with a fine 

 needle. The same thing, it is well known, happens in caout- 

 chouc. Filtering paper presents no visible pores to the mi- 

 croscope while it is wet, but when dry they are very per- 

 ceptible. 



308. It being impossible then, for cutaneous absorption 

 and perspiration, to depend on the physical properties of the 

 epidermis, an explanation has been sought for in its chemical 

 properties. The dried epidermis diminishes in volume, be- 

 comes firmer, more elastic, and slightly yellowish. Macerated 

 in cold water, on the contrary, it swells a little, becomes soft, 

 less elastic, whiter and more opaque. It imbibes this fluid, 

 however, very slowly, and it requires along submersion of the 

 hands and feet in water, for the epidermis to absorb a suffi- 

 ciency of the liquid, to become white and opaque, and yet the 

 epidermis of these regions appears to imbibe it more readily 

 than that of the other parts of the body. It is to this difficulty 

 of the permeability in the epidermis, that we are to attribute 

 the difficulty with which the fluid of ampullae escapes during 

 life, and the slowness with which the skin of dead bodies dry 

 even in the most arid atmosphere, provided the epidermis re- 

 mains entire. It resists putrefaction for a long time; it has 

 been found entire in tombs at the expiration of more than fifty 

 years. Boiling water renders the epidermis white, opaque, 

 and deprives it of its elasticity much quicker than cold water. 

 Continued ebullition extracts a little gelatine from it, which 

 appears to proceed from its adhering face; the residuum does 

 not appear to differ from the entire epidermis. Exposed to 

 fire it burns like horn, and gives out a similar odour. Pure 



