2 82 ELEMENTS of HISTOLOGY. [Chap, xxxiv, 



sheath. The stratum granulosum of the stratum 

 Malpighii is not continued beyond the mouth of the 

 hair-follicle, but there it is generally very marked. 

 The outer root-sheath becomes greatly attenuated at 

 the papilla -in fact, is there continuous with the cells 

 constituting the hair-bulb. 



382. The centre of the hair-follicle is occupied by 

 the root of the hair, which terminates with an en- 

 larged extremity the hair-bulb; this grasps the 

 whole papilla. The hair-bulb is composed of poly- 

 hedral epithelial cells, separated from one another 

 by cement substance, and continuous with the cells 

 of the extremity of the outer root-sheath, from 

 which they originate in the first instance ; just over 

 the papilla there is a special row of short columnar 

 cells, which are in an active state of multiplication, 

 and by which continuously new cells are formed. 

 Thus a gradual shifting of the cells of the hair- 

 bulb upwards into the cavity of the hair-follicle 

 i.e., the hair takes place ; but at the same time 

 these progressing cells become elongated, spindle- 

 shaped, and constitute the cells of the hair substance, 

 except in the very centre, where they remain poly- 

 hedral, so as to represent the cells of the marrow of 

 tJie hair, and in the periphery, where they remain 

 more or less polyhedral, so as to form the inner root- 

 sheath. 



383. The root of the hair, except at the hair- 

 bulb, shows the following parts : The substance of the 

 hair, the cuticle, and the inner root-sheath. The 

 substance of the hair is composed of the Jiair fibres, 

 i.e., long thin fibres, or narrow long scales, each com- 

 posed of hyaline horny substance, and possessed of 

 a thin staff-shaped remnant of a nucleus. These 

 are held together by a certain amount of interstitial 

 cement substance. Towards the bulb they gradually 

 change into the spindle-shaped cells above men- 



