DEVELOPMENT OF THE GKAAFIAN FOLLICLE 403 



the entire breadth of the ovarian cortex. It is now ready for 

 the final steps in the maturation of its ovum and for the rup- 

 ture of the follicle coincident with the approach of the menstrual 

 period. 



The forces which lead to the rupture of the follicle are not fully 

 determined. They are undoubtedly varied, and, in addition to the 

 gradual attenuation of the layer of cortical stroma which covers 

 the free surface of the follicle and is known as the stigma, they 



FlG. 326. A NEARLY MATURE GRAAFIAN FOLLICLE FROM THE OVARY OF A DOG. 



a, fibrous, and 6, cellular layer of the theca folliculi ; c, membrana propria ; d, mem- 

 brana gramilosa, which, as a result of contraction during hardening, has retracted from 

 the nicmbnina propria, leaving a broad artificial space; .E, liquor folliculi; /, discus 

 proligerus; f/, /ona pellucida; ft, vitelline membrane ; i, vitellus ; fc, the germinal spot, 

 lying within the germinal vesicle. Hematein and eosin. Photo, x 150. 



include the gradual accumulation of liquor folliculi under increas- 

 ing tension, the marked congestion of the ovary at the approach 

 of the menstrual period, which is accompanied by the determina- 

 tion of an undue proportion of blood to the theca of the ripe fol- 



