218 



THE SKIN 



follicles. It rests upon a layer, several cells deep, of spheroidal 

 prickle cells. The outermost layer of the outer root sheath is 

 formed by a basal layer of cylindrical cells. 



Dermal Root Sheath. The dermal root sheath presents three 

 layers, an innermost basement membrane or glassy layer, a layer 



FIG. 189. FROM A SECTION OF THE HUMAN SCALP, SHOWING HAIRS IN LONGITUDINAL 



AND OBLIQUE SECTION. 



a, epidermis ; 6, derma ; c, subcutaneous adipose tissue ; e, sebaceous gland. A large 

 sweat gland is seen in the deeper edge of the derma near the middle of the figure. 

 Hematein and eosin. Photo, x 48. 



of circular connective tissue fibres and a similar layer of longitu- 

 dinal fibres. These layers are obviously homologous with the 

 basement membrane, the papillary layer, and the reticular layer 



