3878 DR FOULIS ON THE DEVELOPMENT OF THE OVA, ETC. 
tact with the yelk of each. In all parts of the ovary we find the nuclei of con- 
nective tissue corpuscles dividing. Sometimes these corpuscles are swollen 
out into round bodies containing three to four nuclei. In each egg cluster 
several of the included germ epithelial corpuscles are in a much farther 
advanced stage of development than their fellows. From the walls of the 
meshes inclosing the egg clusters, delicate processes of vascular connective 
tissue grow in, between, and around individual corpuscles in the egg clusters, 
and by a continued intergrowth of the young stroma in this manner each indi- 
vidual of the group becomes at last enclosed in a separate mesh or capsule. 
These last formed meshes are the Graafian follicles. 
As a rule, each Graafian follicle is occupied by one young ovum. The 
protoplasm or yelk of each ovum is in close contact with the wall of each 
Graafian follicle. In contact with the yelk of each young ovum, and indenting 
it, are connective tissue corpuscles, which form part of the wall of each Graafian 
follicle. In the formation of the membrana granulosa, these connective tissue 
corpuscles in the wall of the Graafian follicle, and in contact with the yelk of 
the contained ovum, increase in number by division, their nuclei swell out into 
little vesicles, and at last a perfect capsule of such corpuscles is produced round 
the ovum. This capsule is the membrana granulosa or follicular epithelium of _ 
the follicle. At first the membrana granulosa consists of a simple layer of cor- 
puscles lining the follicle. The individual corpuscles of the membrana granulosa 
in the human ovary measure about 3,/;5th inch. As the ovum becomes mature, — 
the corpuscles of the membrana granulosa proliferate, and then many layers of q 
small corpuscles are produced between the ovum and the follicular wall. Thecells 
of the membrana granulosa are thus derived from the corpuscles of the connec- _ 
tive tissue stroma, and not, as WALDEYER states, from the germ epithelial cor- 
puscles. The follicular space is formed by a breaking down and probable solution _ 
of certain of the corpuscles of the thickened follicular epithelium in the middle 
parts ofthe same. The discus proligerus consists of follicular epithelial corpuscles, 
which are in contact with the zona pellucida of the ovum. The zona pellucida 
or vitelline membrane is formed by a hardening of the outer part of the yelk or 
protoplasm of the ovum, and is not, as REICHERT, PFLUcEerR, and WALDEYER 
stated, a product of the follicular epithelium. At birth the human ovary con- 
tains not less than 35,000 ova, few of which reach maturity. 
In the human ovary at birth the germinal vesicles measure zs45th to zpoth 
of aninch. Most of them are about the same size, and present a sharply-defined 
membranous wall. In some germinal vesicles two or three germinal spots are 
seen. The tunica albuginea is the thickened stroma growing round the ovary. 
At the age of 24 years all formation of ova from the germ epithelium has 
ceased. 
Graafian follicles are not formed from tubular structures in the manner 


