
IN MAN AND OTHER MAMMALIA. 355 
In such a young kitten’s ovary many of the egg clusters are still in connection 
superiorly with the corpuscles of the germ epithelium, but in most cases, we find 
the bundles of young connective tissue which lie between the egg clusters have 
grown completely round them, separating them not only from each other, but 
also from the germ epithelium above. While the corpuscles of the germ epithe- 
lium are thus being enclosed in the meshes of young connective tissue, the 
nucleus of each swells out into a spherical body, around which is gradually pro- 
duced that protoplasm which later constitutes the yelk of the primordial ovum. 
When we trace the bundles of young connective tissue downwards, we find 
they are offshoots of similar tissue of which the central part of the ovary 
consists. In the deeper parts of the ovary we find a very vascular young con- 
nective tissue forming the stroma of the organ, in which are imbedded numerous 
primordial ova, some in a far advanced stage of development. This stroma 
consists of minute fusiform corpuscles and blood-vessels. As the vascular 
bundles or strings of this tissue grow upwards between the egg clusters, delicate 
offshoots of the same insinuate themselves between the primordial ova and 
corpuscles in the clusters, and in this manner nourishment is brought within 
reach of these developing bodies. This interstitial growth begins at the lower 
part of each egg cluster, and gradually the primordial ova become separated 
from each other as the connective tissue thickens in between and around them, 
and they become at last included in separate meshes or primordial follicles. 
Where the egg clusters have not been completely shut in by bundles of connec- 
tive tissue, the fusiform corpuscles of the latter may be distinctly followed up 
as far as the corpuscles of the germ epithelium, and, indeed, seem to disappear 
among them. 
By the growth of the vascular tissue of the stroma among the imbedded 
corpuscles, the egg clusters in all parts of the ovary are gradually subdivided 
or broken up into single egg-containing meshes or follicles; and while this 
process is going on, the primordial ova are rapidly advancing in development. 
In the more superficial parts of the stroma subjacent to the ege clusters, and in 
the fibro-vascular zone of the ovary, the above-described process has already 
taken place. The primordial ova in some of the follicles are of very large size, 
and in the ovary of a four weeks’ old kitten it is of great interest to compare 
the original germ epithelial corpuscles on the surface of the ovary with these 
large primordial ova now imbedded deep in the stroma, and we are thus able 
to observe what an extraordinary change has taken place in them during their 
development; and, what is of more importance, we recognise the nature of the 
change. Examined under a magnifying power of 1000 diameters, the ordinary 
germ epithelial corpuscle on the surface of the ovary appears as if it were of 
such a size that at least three of them would lie side by side on a threepenny piece 
without overlapping it; whereas the highly developed ovum imbedded deeply in 
