74 
OVARIAN PREGNANCY 
relation to the rest of the ovary and the blood clot in which the vesicle 
lay. From a careful study of the sections from the first block, and adjust¬ 
ment to them of the sections from the second, an accurate picture was 
obtained of the relations of the corpus luteum, the unaltered part of the 
ovary, and the vesicle to one another in the longitudinal plane (Figure x). 
The gland was then cut at right angles to this plane, and two supple¬ 
mentary slices (one from the lateral and one from the mesial half) 
through corpus luteum and chorionic vesicle were removed and sectioned. 
By this means a complete picture of the relations of parts in the transverse 
plane was obtained (Figures xi and xn). 
DESCRIPTION OF THE SECTIONS. 
It has been noticed above that the embryonic vesicle appeared to 
occupy a small cavity of irregularly oval shape. The sections reveal that 
this is a space with walls largely composed of recent blood clot, but in 
part lined by a thin irregular layer of fibrin and ovarian tissue in a state 
of coagulation necrosis. To this the villi are attached by characteristic 
broad trophoblastic masses. The cavity represents the normal intervillous 
space, for the most part empty of blood. The chorionic vesicle occupies 
the centre of the implantation cavity. It is collapsed and much folded. 
Its longest measurement is T35 cm., but when rounded out its diameter 
could not have reached a centimetre The villi measure from 2 to 3 mm. 
in length, and are covered by the characteristic two-layered epithelium 
identical in all respects with that of a uterine ovum of corresponding age 
(Plate x, Figs. 13 and 14). They contain vessels filled with nucleated 
red-blood corpuscles. Numerous karyokinetic figures occur in the 
epithelium. 
Remains of an embryo were found within the collapsed chorion, but in 
so damaged a state that it was not considered worth while to give 
the time necessary for reconstruction. There is a thick abdominal stalk 
containing vessels full of nucleated red corpuscles, the yolk-sac is much 
folded, but shows the development of vessels in its walls. The germinal 
disc is cut very obliquely, and the presence of a primitive streak or 
