140 INTERNAL SECRETIONS OF THE OVARY 



represented merely by small cavities and remnants of zona 

 pellucida. In a few cases, larger follicles may become filled with 

 blood and form cysts, or the cells of the theca interna and the 

 membrana granulosa may grow and invade the antrum to form 

 a corpus luteum atreticum. These corpora lutea atretica appear 







Fig. 46. — Ovary of Mouse sterilized when three weeks 



OLD, SHOWING CaVITIES WITH REMAINS OF OVA. 



b.v. blood vessel; f.c. follicular cavity. 



to persist indefinitely, although no physiological function can 

 be attributed to them. Concurrently with these changes in the 

 follicles, the old interfollicular tissue atrophies and proliferation 

 takes place from the germinal epithelium. This proliferation, 

 forming a parenchymatous tissue, constitutes almost the whole 



