IN MAN AND OTHER MAMMALIA. yell 
j,7) and blood-vessels. In a nearly ripe Graafian follicle, just before bursting 
to liberate the ovum, these minute corpuscles in the wall of the follicle outside 
the membrana granulosa swell up and enlarge, producing large fusiform cor- 
puscles (fig. 38, 7,7 ) very similar to the corpuscles of the membrana granulosa at a 
certain stage of development. This condition of the wall of the ripe follicle is 
also well seen in the human ovary. In the wall of the nearly ripe Graafian 
follicle of the rabbit’s ovary, we can trace these large fusiform corpuscles becom- 
ing more and more like the ordinary small corpuscles of the stroma, as we 
examine them in the more external parts of the follicular wall. I have ascer- 
tained by careful observation that from the very first appearance of the 
Graafian follicles to their bursting, no blood-vessels pass into the cavity of the 
follicle to reach the ovum, and yet this body increases enormously in size in a 
short space of time. This great increase in size is brought about by the pro- 
duction of protoplasm or yelk round the germinal vesicle, even after the latter 
has reached a definite size. 
The chief function of the membrana granulosa is to nourish the ovum during 
its development. From the first appearance of the ovum as an ordinary germ 
epithelial corpuscle, until the development of the embryo and its extrusion from 
the uterus, it exists as a parasite. On the surface of the ovary at first it is an 
ordinary germ epithelial corpuscle. In the ovary, during a certain stage of its 
development, it is simply surrounded by vascular nutritious tissue, of which, 
however, it forms no part, but is simply resting on it. Here it imbibes 
nourishment until it is thrown off from the ovary. It then passes into the 
uterus, where changes due to impregnation occur in it, and processes of its 
surface become imbedded in the vascular mucous membrane of the uterus, and 
by the agency of these nourishment is absorbed for the germ till it reaches a 
certain stage of development, when it is thrown off from the parent. In the 
uterus, as in the ovary, the ovum is simply surrounded by vascular nutritious 
tissue of which it forms no part, but simply rests on it, and absorbs nourish- 
ment from it for its own development. 
In the old follicles, some of the cells of the membrana granulosa show a 
distinct but fine cell-wall round the protoplasm which invests the nucleus. In 
some of my preparations of the rabbit’s ovary, the division of the nuclei of the 
corpuscles in the membrana granulosa is excellently seen (fig. 31, v.) In these 
older follicles the protoplasm round the nucleus of the membrana granulosa cor- 
puscle is sometimes very extensive, forming a thick layer which may be found 
drawn out in a fusiform manner (fig. 38, w) at one or more points. 
In certain parts of the adult cat’s and rabbit’s ovary, we find large patches of 
: granular cells, and running in between the cells are processes of connective tissue. 
| These large granular cells have nuclei, but they are indistinctly seen because of 
_\the granular nature of the substance which surrounds them. In most cases the 
