THE PERIODICITY OF (ESTRUS 



139 



rabbit. Bergonie and his co-workers (61-3) showed that while 

 the Graafian fohicles were caused to undergo complete atrophy, 

 existing corpora lutea were not affected. Bouin, Ancel, and 

 Villemin (78) found that the interstitial tissue remained intact, 

 and according to Steinach and Holznecht (595) the interstitial 







'^^iib 



Fig. 45. — Ovary of Mouse sterilized by Exposure to 



X-RAYS when three WEEKS OLD. 



The ovary is largely composed of new tissue derived from the 

 germinal epithelium. 



f.y. follicular remains; ;/./. new tissue. 



tissue is actually augmented from the degenerated follicles. 

 Increase in the interstitial tissue w^as likewise found by Hiissy 

 and Wallart (309) in the human ovary after irradiation. The 

 effects of X-rays on the ovary have also been described in detail 

 by Reifferscheid (529-531). 



In the mouse the changes following X-rays have been des- 

 cribed in detail by Brambell, Fielding, and Parkes (83-6). In 

 the young animal irradiated before puberty the Graafian 

 follicles undergo complete atrophy and are entirely reabsorbed. 

 This atrophy, which includes both the ovum and the membrana 

 granulosa, eventually involves the theca interna in follicles 

 where it is differentiated. Finally, the degenerated follicles are 



