250 CHARLES li. STOC'KAKD AND G. N. PAPANICOLAOU 



blood supply be tied off follicles do not rupture. During this 

 time the nucleus of the egg is still in a resting condition. 



llie ripe follicles break at about the end of the second or the 

 beginning of the third stage. Figure 24 shows a follicle just 

 broken at the conunencement of the third stage. It will be re- 

 called that at this time the active leucocytosis begins in the 

 uterus and the vagina, compare figures 15, 16 and 17. The 

 ovaries are not omitted from this active migration of the leuco- 

 cytes. A number of leucocytes are to be seen in the corpus 

 luteum during its early development, but great numbers of 

 leucocytes are to be found mainly in the atretic follicles, which 

 are now becoming the seat of regressive and degenerative pro- 

 cesses (fig. 25). The eggs in these disorganizing follicles show a 

 peculiar activity expressed by the formation of the maturation 

 spindle. Most of the eggs begin to degenerate before the forma- 

 tion of a polar body, though some of them succeed in completing 

 their maturation divisions. Figure 25 shows an egg within a 

 disintegrating follicle, the follicle containing a great number of 

 leucocytes. This egg possesses a well formed polar body in the 

 process of division. Kirkham has reported similar conditions 

 in the ovary of the mouse, he notices that eggs degenerate after 

 forming the first polar body and the second polar spindle, a con- 

 dition closely similar to that shown in our figure 25. The 

 outline of the polar body is clearly shown in the specimen. 

 The photograph is not 'touched up.' 



The chromatin of the nucleus is to be seen in the center of the 

 egg in figure 25. In all the cases observed, the eggs of the 

 atretic follicles degenerated, the nucleus breaking up into irregu- 

 lar pieces very soon after ovulation had taken place from the 

 ruptured follicles. We failed to find anything to indicate a 

 tendency toward parthenogenetic divisions in the many speci- 

 mens which we have examined as Leo Loeb reported for these 

 animals. 



The ruptured follicles very quickly begin to undergo a reor- 

 ganization resulting in the formation of the corpora lutea. Even 

 during the third stage the corpus luteum is a well circumscribed 

 body beginning its differentiation by the ingrowth of the vascular 



