33' 



HISTOLOGY. 



At the end of lactation the connective tissue increases and the leuco- 

 cytes reappear; as during pregnancy, they form colostrum corpuscles. 

 The lobules become smaller and the alveoli begin to disappear. In old 

 persons all the end pieces and lobules have gone and only the ducts remain. 



The ducts are lined with simple columnar 

 epithelium, surrounded by a basement mem- 

 brane and generally by circular connective tis- 

 sue bundles. Toward the nipple each duct 

 forms a considerable spindle shaped dilatation, 

 the sinus lactiferus. The epithelium of the 

 outer part of the ducts is stratified and squa- 

 mous. 



The skin of the nipple and of the areola 

 at its base contains pigment in the deepest 

 layers of its epidermis. The corium forms tall 



papillae and contains smooth muscle fibers, some of which extend vertically 

 through the nipple and others are circularly arranged around the ducts. 

 There are tactile corpuscles in the nipple, which becomes rapidly elevated 

 upon irritation, due to muscular rather than to vascular action. There are 

 many sweat and sebaceous glands in the areola and occasional rudimen- 



Gland cell. Membrana Oil drops, 

 propria. 



FIG. 383. FROM A SECTION OF THE 

 MAMMARY GLAND or A NURS- 

 ING WOMAN. X 250. 



o.' 



FIG. 384. A., MILK GLOBULES PROM 

 HUMAN MILK. X 560. B., ELE- 

 MENTS OP THE COLOSTRUM OP A 

 PREGNANT WOMAN. X 560. 



i , Cell containing uncolored fat globules ; 

 2, cell containing minute colored 

 fat globules; 3, leucocyte; 4, milk 

 globules. 



FIG. 385. FROM A THICK SECTION OP THE MAM- 

 MARY GLAND OP A WOMAN LAST PREGNANT Two 

 YEARS BEFORE. X 50. 



i, Large excretory duct; 2, small excretory duct; 3, 

 gland lobules, separated from one another by 

 connective tissue. 



tary hairs. The areolar glands [of Montgomery] are branched tubular 

 glands having a lactiferous sinus and otherwise resembling the constit- 

 uent mammary glands. Their funnel shaped outlets are surrounded by 

 large sebaceous glands. The areolar glands are regarded as transitions 

 between sweat glands and mammary glands. 



