Chap. XXXIV.] 



THE SKIN. 



281 



I'. 



fibrous layer of the hair-sac a single continuous 

 layer of transversely or circularly-arranged spindle- 

 shaped cells, each with an oval flattened or staff- 

 shaped nucleus, completely resembling, and generally 

 considered to be, 

 non-striped mus- 

 cle cells. Inside 

 of this layer of 

 the hair-sac is 

 a glassy-looking, /,j 

 hyaline,basement 

 membrane, which 

 is not very dis- 

 tinct in minute 

 hairs, but is suffi- 

 ciently conspicu- 

 ous in large adult 

 hair - follicles. 

 This glassy mem- 

 brane, as it is 

 called, is a direct 

 continuation of 



,i -i sheath ; g, glassy membrane ; h, fibrous coat of hair 



tne Oasement sac ; i, lymph spaces in the same. 



membrane of the 



surface of the corium, and it can be traced as a delicate 



membrane also over the surface of the hair-papilla. 



381. Next to the glassy membrane is the outer 

 root-sheath, the most conspicuous part of the hair-fol- 

 licle. It consists of a thick stratified epithelium of 

 exactly the same nature as the stratum Malpighii of 

 the epidermis, with which it is directly continuous, 

 and from which it is developed. In the outer root- 

 sheath the layer of cells next to the glassy membrane 

 is columnar, just like the deepest layer of cells in the 

 stratum Malpighii ; then follow inwards several layers 

 of polyhedral cells ; and, finally, flattened nucleated 

 scales form the innermost boundary of the outer root- 



Fig. 148. Cross Section through a Human Hair 

 and Hair Follicle. 



a. Marrow of hair ; 6, cortex of hair ; c, cuticle of 

 hair; d, Huxley's layer of inner root -sheath; 

 e, Hcnle's layer of inner root-sheath ; /, outer root- 



