194 William Montagna 



chromophobic. The basophilic granules, as well as the nucleoli, 

 are no longer stainable with basic dyes after the sections have 

 been incubated in ribonuclease, and they must therefore con- 

 tain ribonucleic acids. The intensity of basophilic staining 

 in the cytoplasm of secretory cells is inversely proportional 

 to the number of recognizable secretion granules present. 

 Thus, nucleic acid may be involved in the synthesis of the 

 secretion granules, pigmented or chromophobic. 



Normal axillary apocrine glands contain no glycogen 

 (Montagna, Chase and Lobitz, 1953). However, Schiff- 

 reactive substances other than glycogen are numerous in the 

 apocrine cells and have already been described (Fig. 5). 



Spindle-shaped myoepithelial cells are couched between the 

 single layer of columnar or cuboidal cells and the basement 

 membrane. These cells are 5 to 10 (jl in the widest diameter and 

 50 to 100 (x in length. In transverse sections of tubules they 

 appear as triangular cells between the bases of the secretory 

 cells. The axes of the cells are oriented roughly parallel to that 

 of the tubule. Myoepithelial cells are best developed in those 

 tubules which are lined with the tallest epithelium. When 

 tubules are dilated and the epithelial cells are flat and elong- 

 ated, myoepithelial cells are very delicate or impossible to 

 demonstrate. 



The Ageing Glands 



In the glands of women around 30 years of age, a few seg- 

 ments of tubules become dilated and the secretory epithelium 

 is reduced to cuboidal or squamous cells (Fig. 2). This is 

 actually the onset of ageing changes. Between the ages of 34 

 and 44 there is a very gradual increase in the number of dilated 

 segments in the entire axilla, and in a group of women 40 to 

 44 years old, entire glandular units have a flattened epithelium 

 with or without an accompanying dilatation of the tubules 

 (Fig. 3). The dilated tubules are lined with squamous cells. 

 Although these atrophic changes can be found in nearly all 

 specimens from the late thirties to the late forties, or up to 



