380 



HISTOLOGY OF THE MORBID PROCESSES. 



the question of the existence of a tumor the normal variations in 

 that organ must be carefully considered. In the description of the 

 normal mammary gland it was stated that the microscopical struct- 

 ure differed greatly according to the functional activity of the 



Section from the mammary gland of a nullipara, aged eighteen ; more highly magnified. 



(Altmann.) 



organ. It is proper to recur to those differences in this connection 

 because of the importance of many of the mammary tumors, that 

 gland being one of the common sites of carcinoma and adenoma. 



FIG. 345. 



Section from the mammary gland of a nullipara, aged twenty-two ; slightly magnified. 



(Altmann.) 



In Figs. 343 to 350 sections of the gland in various stages of 

 development and involution are represented. Figs. 343 to 346 

 represent sections from the breasts of nulliparse, aged respectively 

 eighteen and twenty-two years. The parenchyma of the gland has 



