THE OVA AND OVARY IN MAN AND OTHER MAMMALIA. 197 



may be seen in the stroma of such a young ovary. The 

 change which the germ epithelial corpuscle undergoes 

 during its development is the following : 



As soon as the corpuscle is imbedded in the stroma, its 

 nucleus swells up into a round or spherical body, within 

 which generally appears a spot or nucleolus. The nucleus 

 presents a sharply defined limiting membranous wall, and 

 becomes the germinal vesicle of the future ovum. Im- 

 mediately around the nucleus is gradually produced that 

 protoplasm which afterwards constitutes the yelk of the 

 mature egg. In all parts of the oimry, wherever we examine 

 such young developing ova, toe find fusiform corpuscles, like 

 the fusiform corpuscles of lohich the stroma is composed, 

 lyitig in contact with the protoplasm which surrounds the 

 nucleus or germinal vesicle. 



The youngest egg clusters are immediately below the 

 germ epithelium, and many of them are in connection with 

 it. These latter have not as yet, been completely closed in 

 and separated from the -germ epithelial layer by the con- 

 nective tissue bundles of the stroma. 



The clusters of corpuscles in connection at their upper 

 parts with the germ epithelium difier considerably from each 

 other, both in size and form. Some are oval and elongated, 

 others are spherical. Many of them are larger at their 

 lower and middle parts than at the part in connection with 

 the germ epithelial corpuscles. If a vertical section passes 

 down through such clusters as these, such as are swollen 

 out at their lower and middle parts but narrow at their 

 upper parts, we have presented under the microscope the 

 appearance as if bottle-shaped tubes full of round corpuscles 

 extended from the germ epithelium downwards into the 

 stroma of the ovary. These appearances are often seen, and 

 it is important to study them well. It will be remembered 

 that Pfliiger^ described in the young kitten's ovary numerous 

 tubular processes passing downwards from the surface of 

 the ovary into the stroma, in which the germinal vesicles 

 originated, and by the successive divisions of which Graafian 

 follicles containing eggs were formed. I have very carefully 

 examined the ovaries of kittens and puppies, but have failed 

 to find any tubular processes of epithelium passing into the 

 stroma from which Graafian follicles are formed, and it 

 appears to me that Pfliiger is incorrect in stating that such 

 exist in the ovary of the kitten. 



In section, the ovary of a kitten at birth presents a 



' Pfliiger, ' Die Eierstocke der Saiigetliiere und des Menschen,' Leipzig, 

 1863, p. 4. 



