HAIR. 



3 2 3 



A B 



Sebaceous glands. 



increase of undifferentiated cells in the outer sheath and matrix forces 

 the degenerating hair with its inner sheath outward (Fig. 376). The 

 cornified bulb remains near the 

 sebaceous gland at the outer 

 limit of the matrix; after a 

 variable time the hair falls 



OUt. The deep portion Of the Inner sheath. 



outer sheath, emptied of its 

 hair, collapses and shortens, 

 drawing the atrophic papilla 

 upward. The matrix cells pro- 

 liferate causing the epithelial 



rnrrl to return to ite former FlG - 374. FOUR STAGES IN THE SHEDDING o? A HAIR, 



FROM A SECTION OF THE NASAL SKIN OF 7 i MONTHS' 



depth and a new hair develops EMBRYO, x so. 



X, beginning of the new hair. 



in the old sheath. This hair 



in growing toward the surface may complete the expulsion of 



its predecessor. 



Remains of inner 

 sheath. 



Matrix. 



Remains of inner 

 sheath. 



Cornified 

 bulb. 



Matrix. 





Matrix. 



Thin hyaline 

 membrane. 



Epithelial cord. 



/* ' 





". 



Atrophic papilla. - 



Connective tissue. 







FIG. 375. LOWER PART OF FIG. 374. A. 

 X 230. 



FIG. 376. LOWER PART OF FIG. 374, B 

 X 230. 



