72 B. F, KINGSBURY 



Saimont ('05). As has been indicated the conditions within the 

 ovary during growth might well be considered to support this 

 interpretation. The morphological relations during growth are 

 of considerable complexity whereas during the adolescent and 

 adult period (Saimont's 3rd period), the genetic relations of 

 these cells are of the clearest, and show conclusively that these 

 cells arise from the theca interna during the degeneration of 

 Graafian follicles as atresia folliculi. During the growth of a 

 follicle from the primary resting follicle to the appearance of 

 the antrum, the cells of the theca, which becomes progressively 

 more distinct, retain their spindle shape and the general histo- 

 logical appearance of stroma cells. They are almost or quite 

 free from demonstrable lipoid. Next the follicular epithelium 

 the cells are more densely arranged and larger (theca interna). 

 In Graafian follicles of different sizes and degrees of develop- 

 ment, the theca interna cells are largely free from demonstrable 

 lipoid. Frequently, lipoid granules occur and in some cases, 

 particularly in the larger follicles that are evidently nearing ma- 

 turity, the amount of lipoid granules within the cells of the in- 

 ternal theca is quite marked. The cells, while somewhat larger, 

 still retain their spindle shape which is doubtless largely an ex- 

 pression of the mechanical conditions under which they exist. 

 Such follicles showing lipoid content in the theca cells are appar- 

 ently normal. It is this, I believe, that led Saimont to ascribe 

 to the interstitial cells a 'trophic function.' The amount of 

 free lipoid in such cells is small and they do not correspond to 

 his figures of -'adult' cells. 



With the onset of atresia, a succession of changes occurs that 

 markedly increases the fat content in the theca cells and de- 

 termines their transformation to the so-called interstitial cells. 

 From a series of nine photographs showing successive steps I 

 select four stages to illustrate atresia folliculi (figs. 5-8). So 

 well have the salient histological features of atresia folliculi been 

 described, for the cat particularly by H. Rabl, that any extensive 

 description is unnecessary. One of the earliest indications of 

 the onset of degeneration is an alteration in the liquor folliculi. 

 Instead of coagulating on fixation as a loose flocculant mass, it 



