122 EDWARD B. POULTON. 



the layer was thickest here, and has consequently here remained 

 in greatest amount (fig. 6). In one case I observed one or two 

 layers of cells still surrounding an isolated ovum in an appa- 

 rently ripe follicle. While the changes in the granulosa have 

 thus progressed beyond any stage met with in higher mammals, 

 the central contents of the follicle have also undergone modifi- 

 cation. This is seen in the fact that the ovum, although in the 

 follicular contents, was always imbedded (in the cases that came 

 under my observation) on the side of the follicle that projected 

 from the surface of the ovary, and generally (but not invariably) 

 was placed near to the point of greatest projection (fig. 6). 

 Again, the position of the ovum always bore a definite relation 

 to the thickenings of the granulosa. But the ovum could not 

 have any such definite relations if it were floating freely in a 

 fluid such as the liquor foUiculi. Therefore, it seems clear 

 that the central contents of the follicle have become so gela- 

 tinous or viscous that the ovum can be imbedded without 

 change of position (unless, indeed, it is anchored to the side, 

 and of this I could find no proof). At the same time, the 

 microscopic appearance of the central substance has entirely 

 changed, assuming, finally, the appearance of a coarsely- 

 granular network, which does not stain (see figs. 6 and 7) 

 This network has not shrunk away from the granulosa during 

 hardening, but when any contraction takes place, this generally 

 produces a space between the granulosa and the follicular walls 

 (see fig. 1), and the former often becomes much folded. In 

 one instance only I found a considerable cavity between the 

 central contents and the granulosa. Of course it is impossible 

 to decide as to the condition of this remarkable structure 

 during life without the investigation of the fresh organ. It 

 may be that some of the appearances (e.g. granules) are due to 

 coagulation produced by the reagents, but it is certain, from 

 the above considerations, that a great change has taken place 

 in the contents, and that ultimately there appears a substance 

 very diflferent from the ordinary liquor folliculi. In fact, 

 nothing could be more different than the appearance of ordi- 

 nary liquor from that of the central contents in question, when 



