THE OVA AND OVARY IN MAN AND OTHER MAMMALIA. 217 



time the imbedded corpuscles are developing into primordial 

 ova. This intercorpuscular growth of connective tissue 

 takes place in all parts of the ovary wherever groups of germ 

 epitlielial corpuscles become imbedded, and it continues 

 until the inclusion of germ epithelial corpuscles from the 

 surface of the ovary has ceased. It is in this way, and in 

 this way only, that we have Graafian follicles formed. As 

 already explained, the Graafian follicles are the ultimate 

 meshes of the stroma, formed by the growth of the con- 

 nective tissue around the developing primordial ova. As 

 these young ova become surrounded by the vascular tissue, 

 the connective tissue corpuscles in the wall of the follicles in 

 contact with their yelk develop into the corpuscles of the 

 membrana granulosa in the manner described. According 

 to my observations, tubular structures have no existence in 

 the ovary at any period of its development, and I have never 

 detected the formation of Graafian follicles and the cor- 

 puscles of the membrana granulosa in any other manner 

 than that I have indicated. 



By the continued free growth of the vascular stroma 

 throughout the whole organ, the walls of the Graafian 

 follicles become greatly thickened. The oldest and largest 

 Graafian follicles are situated in the deepest parts of the 

 stroma ; that is what we would naturally expect, for they 

 were the first formed, and lie surrounded by a great number 

 of blood-vessels which are branches of the large trunks 

 entering the ovary at the hilum. 



After birth the corpuscles of the germ epithelium gradually 

 become smaller in size, losing their columnar form, till at the 

 age of six years, in the case of the human ovary, they present 

 the appearance of small flattened corpuscles (fig. 23, h). 

 They are very small, measuring in their longest diameter not 

 more than the -roVoth part of an inch. The epithelial mem- 

 brane composed of such corpuscles can be stripped off the 

 surface of the ovary Avithout difficulty. In the human ovary 

 at twelve years of age, the epithelium has preserved an 

 almost identical appearance to that above described, the 

 epithelial corpuscles still remaining of very small size. In 

 the ovary of an adult, the epithelial corpuscles do not 

 measure more than the xoVo^h to the -2-^0 "oth part of an inch 

 in diameter. 



General Conclusions. 



The following general conclusions have been arrived at in 

 the course of my investigations : 



The corpuscles of the germ epithelium are derived by direct 



