78 THE SKIN. 



supported by all recent experimenters, is, that substances dis- 

 solved in water are not absorbed through the skin. 



Fortunately the skin does not absorb animal poisons as a 

 rule, unless it is abraded. Some acrid matters destroy the 

 cuticle, and induce inflammation of the skin, but usually the 

 cuticle affords sufficient protection against the accidental in- 

 troduction of noxious principles into the blood by the skin. 



I have, in the next place, to consider the cutaneous appen- 

 dages, and the first to notice is 



HAIK. The hairy covering of animals is continuous with 

 the cuticle, and on the application of a blister, not only is 

 the cuticle raised, but the hairs are drawn out of their 

 follicles. 



Hair is composed of a softer, medullary portion or pith, 

 and a harder cortical layer. The medulla or pith is traced 

 from near the point to the deepest part of the hair-follicle, 

 where masses of spherical cells are seen to envelop a papilla 



Fig. 177. Fig. 178. Fig. 179. Fig. 180. 



linhi" Stte1h2rtoSSi~ A halr papilla ' showin S its relations with the hair bulb and 



J&lSz3*ZS*SsS. stem ot W001 from * sheep ' showin8 the ** 

 &SSs3SSSl3SSStt&&te hair In its fomcle; '' 



Fig. 180. (EEISSNEB.) Transverse section of the inner sheath of the hair in the pig. 



.or vascular projection of the skin, from which, indeed, the 

 hair is formed. The spherical cells, which constitute the root 

 of the hair, may be seen continuous with the cells of the 



