192 DR. JAMES FOULTS. 



existj that is, as far as I can find, from the ninth month till 

 a short time after birth, they present the structure ascribed 

 to them by Pfliiger, with the exception already mentioned, 

 that there is as little of membrana propria in them as there 

 is in the primary follicles. In the tubes, and mostly in the 

 middle of them, as Pfliiger described, we meet with egg cells 

 distinguished by their size and form, often immediately con- 

 catenated one behind the other. Whether in the tubes new 

 egg cells are formed, I cannot decide ; but I think it likely, 

 because here, as well as on the surface epithelium, some 

 epithelial cells may develop into egg cells. Division of the 

 egg cells in the tubes Pfluger seems to have observed, but I 

 have not seen it in fresh specimens. 



"Follicles are formed from the tubes as well as from the 

 egg compartments, directly through the growth of interstitial 

 issue. At the lower end of the tube, as may be well 

 explained from the want of a membrana propria, interstitial 

 tissue grows into the tubes and incloses the individual egg 

 cells along with a portion of the not fully developed 

 epithelial cells Avhich surround them, and in this way 

 primary follicles are produced. 



" The tubes of Valentin and Pfliiger can lay claim only to 

 a secondary importance, and are not essential for the egg 

 and follicle formation ; the greater part of the follicles have 

 undoubtedly an earlier existence, long before these tubes are 

 formed." 



My observations have been made on the ovaries of calves, 

 kittens, cats, puppies, rabbits, human foetus, &c., and in the 

 present paper I have described what I have seen in the 

 ovaries of young kittens and of the human foetus with the 

 object in particular of demonstrating that, whereas the eggs 

 are derived from the germ epithelium, the nutrient cells of 

 the ovum, or the follicular epithelial cells, are derived from 

 the cells of the stroma of the ovary. 



The Ovary of the Kitten. 

 I shall first describe the structure of the ovary and the 

 development of the ova in a kitten of two or three weeks ; 

 and I may here remark, that I know of no animal better 

 suited than the kitten to show the relation of the germ 

 epithelium to the stroma of the ovary. 



In a thin vertical transverse section of a two weeks' old 

 kitten's ovary we may distinguish 



1st, The germ epithelium. 

 2nd, The zone of egg clusters. 

 3rd, The fibrovascular stroma. 



