of Edinburgh, Session 1874-75. 
437 
3. The Development of the Ova, and the Structure of the 
Ovary, in Man and other Mammals. By James Foulis, 
M.D. (Edin.) Communicated by Prof. Turner. 
After an historical introduction, in the course of which the author 
gave an abstract of the important observations of Pfliiger and Wal- 
deyer, he proceeded to state his own observations on the develop- 
ment of the ova and structure of the ovary in calves, kittens, and 
the human female. The following general conclusions have been 
arrived at by the author in the course of his investigations : — 
The corpuscles of the germ epithelium are derived by direct pro- 
liferation from those columnar corpuscles which invest the median 
side or surface of the Wolffian body, and which are continuous with 
the layer of columnar corpuscles that lines the pleuro -peritoneal 
cavity of the embryo in the early stages of development. The 
stroma of the ovary in the early stages of development is pro- 
duced by a direct growth out from the interstitial tissue of the 
Wolffian body immediately beneath the germ epithelium on the 
median side of the Wolffian body. 
The germ epithelial corpuscles proliferate by fission. In the 
human foetal ovary of 7J months they measure 2"§V v ^ oVo °f an 
inch in their longest diameter, and about °f an inch in their 
shortest diameter. Each germ epithelial corpuscle is a nucleus 
surrounded by a thin film or investment of clear protoplasm. The 
nucleus of each germ epithelial corpuscle becomes the germinal 
vesicle of the mature ovum ; and every germ epithelial corpuscle is 
potentially an ovum. In the act of becoming primordial ova, the 
nucleus of each germ epithelial corpuscle swells up into a spherical 
corpuscle with dark granular contents, within which is generally 
seen a nucleolus, and around which is produced clear homogenous 
protoplasm which subsequently forms the yelk of the ovum. Germ 
epithelial corpuscles are seen in all stages of development into 
primordial ova. In each primordial ovum the spherical germinal 
vesicle presents a sharply defined limiting membranous wall. 
Within the germinal vesicle is the nucleolus or germinal spot. All 
the ova in the ovary are derived from germ epithelial corpuscles. 
In all parts of the ovary processes of vascular connective tissue 
stroma grow in, between and around certain of the germ epithelial 
