Female Axillary Apocrine Sweat Glands 189 



abundance of apocrine glands; Europeans, having the fewest 

 apocrine glands, belong to the highest order, but the Australian 

 Negroes, with the most glands, belong to the lowest. Actually, 

 the frequency and the distribution of apocrine glands have 

 much the same variety in all races (Woollard, 1930). 



Apocrine axillary glands develop in the fifth foetal month 

 as adventitious buds from hair follicles. At the end of foetal 

 life they open into the funnel-shaped depression of the pilo- 

 sebaceous canal; they are incompletely formed at birth and 

 their characteristic properties develop slowly. Growth, final 

 development and activity are closely related to sexual develo- 

 ment and maturity. The glands attain full development at 

 puberty, and they are said to undergo involution in senescence 

 (Ito, Tsuchiya and Iwashige, 1951). 



Axillary apocrine glands are compactly coiled, tubular 

 glands (Horn, 1935; Sperling, 1935), with adjacent loops 

 joined by shunts or terminating in blind sacs. The deepest 

 portion of the secretory coils extends into the subcutaneous 

 fat. The single, or, rarely, doubled, duct of the axillary 

 gland, imbedded in the loose connective tissue around the 

 hair follicle, is perfectly straight. It runs near and parallel to 

 the hair follicle and opens inside the pilosebaceous orifice. 

 When ducts open directly onto the surface, the associated hair 

 follicle may have degenerated. 



The secretory epithelium is composed of irregularly colum- 

 nar cells (Fig. 1), with the terminal portion often elongated 

 and projecting into the lumen. The free border of these cells 

 terminates in very fine cytoplasmic processes which give the 

 surface of the cells the appearance of a cuticular or brush 

 border. Occasionally, segments of individual tubules, or 

 entire tubules, are lined by simple cuboidal epithelium. When 

 the tubules are excessively dilated, the epithelium is reduced 

 to cells so flat that they resemble endothelial cells. The 

 epithelial cells rest upon a mesh of myoepithelial cells aligned 

 roughly parallel to the axis of the tubule. Outside of the 

 myoepithelial cells is a thick, hyalin basement membrane. 



In order to understand senile changes it is necessary to 



