210 



NORMAL HISTOLOGY. 



Sebaceous gland from the external auditory canal. (Benda and Guenther's Atlas.) a, epi- 

 thelium continuous with that lining the hair-follicle ; b, layer of proliferating epithelium 

 lining the sac of the gland ; c, enlarged cell beginning to undergo fatty metamorphosis 

 of the cytoplasm ; d, mass of sebum derived from a single epithelial cell. 



tion of the cells in the deeper layers of the rete mucosum and those 



Fig. 188. 



b : • ••-^. ; ^.. ;_.--•/-- •/•••s.„;C 





Section through the root of the nail of a sixth-months fcetus. (Ernst.) a, matrix of the nail 

 formed by an invagination of the rete mucosum. Near the point indicated by the letter 

 the epithelial cells have begun to change into keratoid material, b, loosened scales of the 

 surface of the nail; c, remains of the foetal cuticle which have not become keratoid. 

 The letter a and line proceeding from it both lie in the corium. 



composing the hair. The whiteness of the hair which comes with 

 years is due to little spaces which appear in unusual numbers 



