164 Veterinary Obstetrics 



whole, these are rare exceptions in other animals, while, in the calf, they 

 are extraordinarily common. 



It is readily understood that the prematurely appearing follicles do not 

 rupture, for there is wanting, at this time, the hyperaemia of estrum, 

 through which, after the advent of puberty, the intrafoUicular pressure in 

 adults becomes increased. 



Heitz could further determine that all follicles existing in calf ovaries had 

 emanated from simple primordial follicles and had no relation to sheath 

 follicles or ovarial adenoma. 



According to Simon ' the large, distended, degenerated granular cells 



appearing so numerously, lying in the inner zone against the inner walls of 



the cyst, play an important role in the genesis of these cystic follicles. 



y~ The most convincing argument of all would be the recognition of an ovum 



Xin such cysts. This evidence it has thus far been impossible for us to 



\ adduce, since the cysts, in the preparation of the material, were incised or 



J ruptured, permitting most of the contents to escape. Zschokke has searched 



) many cysts for ova but was unable, in a single case, to detect any. Accord- 



/ ing to this author, it is well nigh impossible to secure the entire follicular 



I contents and adequately search them microscopically. The exact contents 



of these follicles in the cow need be fully determined. 



I believe it is possible to explain the cause of the existence of cysts directly 

 by the structure of their walls, without taking into consideration the forma- 

 tion or nonformation of the corpora lutea, which view, however, as is made 

 clear by the preceding quotations, is by no means established in a manner 

 free from objection. 



If we study the delicate tissues which make up the Graafian follicles of 

 the ovary, we are at once impressed with the thought that the least general 

 or local pathologic changes must serve to interfere with the nutritive pro- 

 cesses in them. 



If the contents of such a follicle perish as a result of these changes, the 

 theca, which no longer receive adequate nutrition, cannot fill the cavity 

 and thus obliterate the existing defect. This may be seen in follicular 

 atresia, in which a fine-meshed connective tissue network grows out into 

 the follicular cavity from the theca interna. Through transudation from the 

 few existing vsesels, the liquor folliculi becomes increased and the follicular 

 capsule then surrounds a cavity filled with a fluid poor in cell contents. 



Contemporary with the destruction of the follicular contents, there occur 

 changes in the follicular wall. It becomes markedly poor in cells and ves- 

 sels. The previously round cells assume a polygonal form and show polar 

 ovitgrowths, which establish connections with neighboring cells. There are 

 now observed, in relatively large numbers, round cells appearing scatter- 

 ingly amongst the polygonal ones. The inter-cellular substance, at first 

 fibrous, becomes more homogeneous in the outermost zone, which is al- 

 most wholly devoid of cells, and stains intensively with eosin. The vessels 



'A. Simon, Anatomisch-histologische Untersuchungen der Ovarien von 95 

 Kastrirten Kiihen, Berner Inaugural-Dissertation, 1904. 



