272 



ELEMENTS OF HISTOLOGY. [Chap, xxxni. 



In the active gland each epithelial cell is capable 

 of forming in its interior one or more smaller or larger 

 oil globules. These may, and generally do, become 

 confluent, and, pressing the nucleus towards one side 

 of the cell, give to the latter the resemblance of a fat- 

 cell. The oil globules are finally ejected by the cell- 

 protoplasm into the lumen of the alveolus, and repre- 



Fig. 144. From a Section throiuli the Mammai-y Gland of Cat iii a 

 late stage of Pregnancy. 



a, The epithelial cells lining the gland-alveoli, si-ou in profile ; 6, the same, seen 

 from tbe surface. Many epithelial cells contain an oil globule. In the cavity 

 of some of the alveoli are milk globules and granular matter. (.Atlas.) 



sent now the milk globules. The cell resumes its 

 former solid character, and commences again to form 

 oil globules in its protoplasm. The epithelial cells, 

 as long as the secretion of milk lasts, go on again 

 and again forming oil globules in the above manner 

 without being themselves destroyed (Langer). These 

 milk globules, when in the lumen of the alveoli, are 



