192 William Montagna 



traces or none at all. Iron is said to be normally more abun- 

 dant in specimens from middle-aged subjects. The distribu- 

 tion of iron is erratic; adjacent tubules in the same specimen 

 or separate coils of the same glandular unit may show dif- 

 ferent amounts of iron. Some cells may abound in iron whereas 

 morphologically identical cells may possess none. The pres- 

 ence or absence of iron is an individual characteristic. Iron is 

 nearly always in the form of small granules ; large iron granules 

 are very rare (Bunting, Wislocki and Dempsey, 1948; Homma, 

 1925; Homma, 1926). Iron may be present in the tall, 

 apparently secretory cells, as well as in the low cuboidal ones. 

 Regardless of the amount of iron in the epithelium, the residual 

 secretion in the lumen of the tubules contains none (Montagna, 

 Chase and Lobitz, 1953; Zorzoli, 1950), unless the epithelium 

 is collapsing and undergoing obvious degenerative changes. 

 Iron is found as a part of, or together with, the small yellow 

 pigment granules; the large dark-brown granules rarely 

 contain it. When they do, only a thin film at the periphery 

 is reactive to the iron tests, and the brown pigment shows 

 through unchanged. The amount of pigment in the cells is no 

 indication of the presence of iron, but iron is found only in the 

 small yellow granules and only if the large brown ones are 

 also present in the same cells. This has led Manca (1934) to 

 call the pigment which contains iron, haemosiderin, the one 

 which does not, wear-and-tear pigment. However, the yellow 

 pigment cannot be called haemosiderin since it may or may not 

 contain iron. Perhaps an iron-containing substance may or 

 may not be associated with the yellow pigment (Zorzoli, 1950). 

 It is possible that whether or not iron is present, the yellow 



PLATE I 



Fig. 1. Segments of a normal apocrine sweat gland from the axilla of a 33- 

 year-old woman. The height of the epithelium varies from one segment to 

 another. On the extreme right are the coils of an eccrine gland. Stained with 



Heidenhain's haematoxylin. 



Fig. 2. Dilated segments of an apocrine gland from the axilla of a 41 -year-old 



woman. The epithelium is reduced to long squamous cells. Most of the 



colloid in the lumen has fallen ; bits which cling to the slick are stained meta- 



chromatically. Stained with toluidine blue. 



