THE OVA AND OVARY IN MAN AND OTHER MAMMALIA. 205 



human foetal ovary in section, I stated that the germ epi- 

 thelium passed round the ovary from one lateral border to 

 the other, dipping into and lining certain tube-like struc- 

 tures and tubiform depressions which appear to pass from the 

 surface downwards into the organ. Now, if vertical sections 

 are made through a young ovary such as above described, 

 whose surface presents numerous irregularities, we have the 

 appearance presented as if tube-like structures (fig. 4, p,p) 

 pasjed down from the surface of the ovary into the substance 

 of the organ, and these are all lined by germ epithelium. 

 Similar tube-like structures are produced when sections are 

 made through the convoluted surface of a brain, and the grey 

 matter might even be compared to the germ epithelium, inas- 

 much as it lines these sulci. But such structures are not tubes, 

 nor are the similar appearances seen between the irregu- 

 larities of the surface of a young fcetal ovary. 



An examination of the young ovary, looking down on its 

 surface from above, soon convinces us that there are no real 

 tubular structures passing from the epithelium into the 

 organ. On bringing the germ epithelium into view, and 

 then slightly depressing the tube of the microscope, one sees 

 large and small round groups of spherical corpuscles separated 

 from each other by the connective tissue of the stroma, as was 

 described by Waldeyer. Some of these gi'oups are still in 

 communication with the germ epithelial corpuscles, as may 

 be seen in vertical sections where the knife has passed 

 through a group of corpuscles not yet completely included in 

 a mesh of the upward growing stroma. 



In the germ epithelial layer which dips down into and 

 lines the depressions of the surface of the ovary (fig. 4, p, p), 

 we find the corpuscles undergoing changes during their de- 

 velopment similar to the changes which the corpuscles of the 

 germ epithelium in other situations undergo. At the bottom 

 and sides of the sulci, among the corpuscles of the germ 

 epithelium, we find large spherical nuclei with a thin invest- 

 ment of protoplasm, and large primordial ova, such as may 

 be found in all parts of the germ epithelial layer, whether it 

 lines depressions or passes over prominences of the surface of 

 the ovary. 



Frequently large egg clusters are formed under the germ 

 epithelium which lines the furrows or sulci, and it often 

 happens that the walls of these furrows come in contact; 

 pushed together, as it were, by laterally situated expanding 

 egg clusters. At the bottom of the furrows, where the 

 epithelial walls come in contact, connective tissue passes 

 tlirough among the corpuscles, and in this way large egg 



