280 



THE SKIN 



latter, being identical with the deeper portion of the epidermis, must 

 possess a close structural resemblance to the rete mucosum, while its 

 inner portion, like the horny layer of the skin, is more or less cornified. 

 There is thus an outer and an inner epidermal root sheath corre- 



FIG. 272. FROM A SECTION OF THE SKIN OF AN INFANT'S ARM, SHOWING SMALL 

 IMMATURE HAIR FOLLICLES IN TR/JSTSECTION. 



a-a, epidermis; b-b, derma; c-c, subcutaneous connective tissue; d-d, muscle. 

 Hematein and eosin. Photo. X 95. 



spending respectively to the mucous and horny layers of the epidermis; 

 the cornified portion, inner root sheath, becomes progressively thinner 

 toward the hair bulb. The hair, on the other hand, represents an ex- 

 cessively developed horny layer whose rete mucosum is found in the 

 germinal layer of the hair bulb. 



The mature hair is divisible into a hair shaft or free portion, and a 

 hair root or concealed portion. The latter is inclosed within an epi- 



