ORIGIN OF THE CORPUS LUTEUM 



159 



losa cells (fig. 15 b). Their cytoplasm increases in volume so 

 that the cells are now much larger in size, varying from 9.5 x 11/x 

 to 14 x 21 \i in diameter in sections, or half again as large in 

 diameter as before rupture. The nuclei become rather more 

 vesicular. Most important is the fact that many of the larger 



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Fig. 15 a, Part of wall of developing corpus luteum in stage of spindle-cell 

 invasion (ova in tubes). Formol fixation, Mallory's connective-tissue stain. 

 X 110. X, area of active invasion by spindle-cells (at apex of fold in wall). 



cells now have in their cytoplasm large spaces containing rounded 

 bodies resembling rings in section, which we have already seen 

 (pp. 137, 139) to be characteristic of the so-called 'lutein cells' 

 of the young corpus luteum in swine and to be due to the pres- 

 ence in the cytoplasm of an oily lipoid substance. 



THE AMERICAN JOURNAL OF ANATOMY, VOL. 26, NO. 1 



