238 Mr. E. A. Schafer. On Immature Ovarian Ovum [Mar. 18, 



serves to connect the germinal spot with, the inner wall of the 

 germinal vesicle. The network is hardly at all stained by logwood, 

 thns presenting a marked contrast to the substance of the germinal 

 spot ; moreover the nodal points are not marked and the whole struc- 

 ture is comparatively indistinct. It is jnst such an appearance as 

 can be produced in an albuminous fluid by coagulating reagents, and 

 I am at present unable to decide clearly in my own mind, whether it 

 is natural or has thus been formed artificially. In other 07a, chiefly 

 those of smaller size (figs. 2, 3, 4, and 8), the germinal spot is 

 composed of two distinct substances, a homogeneous matrix (ma.) 

 staining but slightly, and a number of coarse granules which are 

 darkly stained by the logwood. The granules may be scattered 

 equally thickly over the whole matrix, or they may leave a peripheral 

 layer of the spot clear, or again there may be a clear part in the 

 centre (fig. 3, c) as well as at the periphery of the spot ( 1 ).* This last 

 condition I have especially noticed in some of the smallest ova. As a 

 rule the intra-nuclear network above described in the larger ova is 

 not to be seen in the smallest ones. This may be accounted for by 

 the assumption that the network is formed subsequently by a pro- 

 trusion of the homogeneous substance of the spot ; i.e., if we regard 

 the network as a natural formation. On the other hypothesis, namely, 

 that it is an artificial production, we must assume that there is less 

 albuminous matter in the fluid which fills the germinal vesicle of the 

 smaller ovum, to what there is precipitated around the spot, and does 

 not adhere together in the form of reticulating filaments. In 

 almost all these smaller ova the germinal spot lies near the wall of the 

 vesicle. 



Germinal Vesicle. — In all the ova the wall of the germinal vesicle 

 is a very distinct membrane which becomes, stained by logwood, but 

 not very darkly. When a portion of the membrane of the germinal 

 vesicle of one of the larger ova is separated and examined on the flat, 

 it has a finely punctated appearance, and in profile it can be seen 

 that this is d_ue to minute pits with intervening thickenings upon the 

 inner surface of the membrane (fig. 7, a and h). ( 2 ) The action of 

 the reagents employed generally produced a shrinking of the vesicle, 

 so that its outline in many cases became irregular (fig. 3), but where 

 this shrinking has not taken place, it is almost perfectly spherical 

 except in the largest ova. With the exception of the germinal spot 

 the contents of the germinal vesicle in the younger ova remain abso- 

 lutely clear and unstained,, so that we must either assume that there 

 is very little albuminous matter naturally present, or, as above 

 suggested, that this has been precipitated around the germinal spot 

 during the process of hardening the tissue. In one small ovum two 



* The small numbers above the line indicate references to the literature of the 

 subject. These will be found at the end of the paper. 



