DESCRIPTION OF SECTIONS 
79 
stitutes the most important point in the specimen. This body presents 
the usual characters of a corpus luteum of the 2nd month of pregnancy. 
Although it approaches quite closely to the surface of the ovary at the 
lower end, it has clearly not ruptured upon this aspect of the gland, for 
its walls are here quite intact. The only break in its contour is 
directed towards the mass of blood clot enclosing; the vesicle. Figure x 
shows the margin of the opening in longitudinal sections, while 
Figure xi shows a portion of it cut transversely. The corpus luteum 
is approximately globular, but somewhat flattened in the transverse 
plane of the ovary. The circumference can be seen rounding in on all 
sides towards the opening. The centre of the body is occupied by the 
usual irregular mass of young connective tissue and partly organised blood 
clot. This is continued outwards as a hyaline fibrinous band, through the 
break in the capsule into the necrotic stroma and blood clot surrounding 
the chorion, while the normal stroma investing the corpus luteum passes 
inwards between it and the blood clot, as far as the margins of the 
fibrin mass protruding through the gap. The apparent width of the gap 
is considerably diminished if allowance be made for the darker masses 
represented as occupying its lips in the figures; these are necrosed portions 
♦ 
of the corpus luteum. 
It is quite evident from this description that the chorionic vesicle is 
situated opposite the break in the capsule of the corpus luteum, and that it 
lies entirely outside it. The vesicle obviously lies in an implantation cavity 
excavated in the ovary and now greatly distended by recent haemorrhage. 
It may be taken for granted that the spermatozoon which effected 
fertilization obtained access to the Graafian follicle through the opening on 
the surface formed by the rupture of the follicle. The only other alternative 
is that the fertilized ovum adhered to the ovary and implanted itself 
therein from without. The appearances do not at all suggest such an occur¬ 
rence ; it is, moreover, highly improbable. On the other hand, from what we 
know of the powers of movement of the spermatozoon, the first alternative is 
by no means far-fetched. We assume therefore that after fertilization the 
ovum was retained within the follicle by the closure of the rent in its wall. 
During the early stages in the formation of the corpus luteum, the ovum 
