196 DR. JAMES FOULIS, 



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 

 connective tissue forming the stroma of the organ, in which 

 are imbedded numerous primordial ova, some in a far ad- 

 vanced stage of' development. This stroma consists of 

 minute fusiform corpuscles and blood-vessels. As the 

 vascular bundles or strings of this tissue grow upwards be- 

 tween the egg clusters, delicate off'shoots of the same 

 insinuate themselves between the primordial ova and cor- 

 puscles 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 connective 

 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 egg 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 dia- 

 meters, 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 the stroma appears as large as a 

 florin or a half-crown piece, and tlie nucleus or germinal 

 vesicle as large as a threepenny or fourpenny piece. Between 

 these two extremes young ova in all stages of development 



