ORIGIN OF THE CORPUS LUTEUM 



169 



second month of pregnancy or may disappear long before (fig. 21). 

 In appearance the cells of these clumps resemble the theca cells 

 of the stage of invasion. In osmium-tetroxide preparations, 



5 ir>r~ 



\K. c. 



Fig. 21 Portion of corpus luteum from second month of pregnancy (foetuses 

 35 mm. long), showing a clump of theca interna cells still in their original posi- 

 tion. Formol fixation. Mallory's connective-tissue stain. X 450. 



some retain many lipoid globules, others have lost all of their 

 fatty inclusions; but many present the previously noted foamy 

 appearance of the cytoplasm, due to the presence of many 



