346 DR FOULIS ON THE DEVELOPMENT OF THE OVA, ETC. 
identical in structure. In 1671, De Graar introduced the word ovary, and 
described the Graafian vesicles as ova, which he said were produced in the 
ovary. The distinction between the true ovum and the Graafian vesicle was 
not made out till the year 1824, when Messrs Prevost and Dumas, by 
numerous observations, were led to the conclusion that the ova were con- 
tained in the Graafian vesicles before conception. The mammalian ovum itself 
was discovered by Von Barr in 1827, and in 1834 Coste and others dis- 
covered the germinal vesicle in the mammalian ovum. In 1835, WAGNER 
demonstrated the germinal spot and established the doctrine of a general 
uniformity in the structure and mode of origin of the ova of animals. 
The discussions in the numerous works which appeared between the years 
1835 and 1838 turned more or less on the question whether the germinal 
vesicle, or the ovum itself was first formed, or whether the Graafian vesicles 
were first produced, and the eggs subsequently developed in them. In MULLER’s 
“ Archiv. fiir Anatomie und Physiologie,” 1838, there is a paper by VALENTIN, 
on the development of the Graafian follicle in the ovary of mammals. He 
described the Graafian follicles as being formed within long tubes which origin- 
ally constituted the special structures of the ovary, as the seminiferous tubes 
do of the testicles, but which become obliterated by the increasing growth of 
the Graafian follicles. . 
Martin Barry, by his numerous observations, was led to the conclusion 
that the germinal vesicle is the part which first makes its appearance in the 
stroma of the ovary at the commencement of the formation of the ova. 
VALENTIN, BiscHoFF, and others, held the view that the Graafian follicles 
may be detected in the stroma of the ovary before any part of the ovum can he 
distinguished. 
It was with the appearance of Priiicer’s work that the views of the 
structure of the ovary and development of the ova took anewturn. VALENTIN, 
in 1838, as already observed, first demonstrated the branched and tubular 
glandular structure of the ovary; an observation which BiLLRoT#H corroborated. 
Little attention, however, was paid to this observation until it was rediscovered 
by Priiicer, who in a detailed monograph developed his views respecting the 
structure of the ovary. 
In the first place, Prtiiger showed that the Graafian follicles with the eggs 
do not appear individually and independently in the stroma of the ovary. He 
described tubes as passing from the surface of the ovary down into the stroma, 
composed of a structureless membrana propria, by the inflections of which the 
several Graafian follicles are successively divided off. 
Pricer, (as quoted by WaLpryver),* stated that the tubes lying close 
beneath the surface of the ovary terminate by ccecal extremities, and in these 
* Srricker’s “Handbuch der Gewebelehre,” article Ovary, by WaLpzyEr, translated by Mr Power. 


