XAIL3 AXD HAIR. 



125 



FIG. 5. 



Summary. The essential points in the anatomy of the 

 hair-follicles and the connections of the hairs with the skin 

 may be summed up in a few words : 



The hair-follicle consists of an 

 inversion of the true skin, with 

 some modifications in the arrange- 

 ment of its anatomical elements, 

 and presents at the bottom an 

 ovate papilla, upon which the bulb 

 of the hair rests and to which it 

 is closely attached. The root of 

 the hair is invested with two mem- 

 branes; the outer sheath corre- 

 sponding to the Malpighian layer 

 'of the epidermis, and the inner 

 sheath corresponding to the horny 

 layer. These membranes, with the 

 membranes that form the wall of 

 the follicle, extend to the junction 

 of the lower two-thirds with the 

 upper third of the follicle, or the 

 openings of the sebaceous glands, 

 with which all the hairs are pro- 

 vided. If continued upon the skin, 

 of course the layers would be re- 

 versed, the inner root-sheath be- 



o-ni 

 epi- 



rrvmincr flip nntpr lavpr nf flip *vm Hair and hair-follicle of medium PIZP. 



in g IJ - lajei me epi- nia?nifi e d flfty diameters-a, shaft 



flpvinii; flip nnfpr rrnt dlipntTi T^oir>ry of thehair; 6, root; c. bulb, rf. epi- 



"Sj" >Ot-sneatn Deing dermis of the hair; V. internal root- 



pnntinnrmj; \vitli tViP "\ralrirrliiQn sheath;/, external sheath; </, 



^lt me Jlialplgnian amorphous membrane of the folli- 



layer. The hair itself is an ap- fon^^ai^fes^^pma-f 



pendage of the epidermis, and is " etory ducts of ' th ' e sebace ' cu ^ 



glands ; /, derma at the point of 

 opening of the follicle ; m, mucous 

 layer of the epidermis ; n, horny 

 layer of the epidermis ; o. termi- 



continuous with the inner root- 

 sheath, Which Corresponds to the nation of the internal sheath of the 

 -Hi- i -i i T, root of the hair. (KQLLIKER. Ele- 

 JMalplghian layer. it rests Upon ments <?hi*tologie humaine, Paris, 



and is produced by the papilla, 



as the nail rests upon the papillae of its matrix. The root of 



