264 



THE SKIN 



Cylindrical Cell Layer (Stratum Cyllmlrlcum). The deepest cells 

 of the stratum mucosum are elongated in a direction nearly perpendicu- 



FIG. 261. SECTION OF THIN SKIN* FROM ABDOMEN OF XEGRO, SHOWING THE DISTRI- 

 BUTION OF THE PIGMENT GRANULES IN DERMAL AND EPIDERMAL CELLS. X 750. 



lar to the basement membrane upon which they rest; they are thus 

 irregularly cylindrical in shape. It is these cells which in the pig- 



mented portions of 

 the body, i.e., areo- 

 Ia3 of the nipples, 

 scrotum, circu- 

 manal region, etc., 

 and in the skin of 

 brunettes and the 

 colored races con- 

 tain the pigment 

 which gives rise to 

 the darkened color 

 of the skin. 



In the skin of 



FIG. 262. SECTION OF THIN SKIN FROM ABDOMEN OF the negro, the pig- 

 LIGHT BROWN MULATTO.* X 750. men t (m e 1 a 11 i c) 



granules, while 



most abundant in the basal cylindrical cells, are nevertheless present, but 

 in progressively smaller number, in all of the outer cell layers. In the 



