88 
OVARIAN PREGNANCY 
destructive activity of the trophoblast would obviously have brought about 
the same condition of things as in Thompson’s case. If the case 
had proceeded further without rupture of the ovary, the ultimate result 
would presumably have been destruction of the corpus luteum. The series 
of cases in which intra-follicular imbedding had occurred show that in 
these also the final result would be disappearance of the lutein tissue, so 
that in the final issue the initial differences due to variation in the site 
of implantation would disappear, after a few weeks or months. Variation 
in the site of implantation is due then only to differences in the degree 
to which the ovum burrows into the connective tissue of the ovary, and 
the cases readily arrange themselves in series on that basis. 
The case of Hewetson and Jordan-Lloyd forms the extreme term of a 
series of which the case of van Tussenbroek is the first term. It repre¬ 
sents a case in which, probably at a comparatively early stage, the gestation 
sac had ruptured and abortion had taken place into the pouch of Douglas. 
The present case is an instance of a chorionic vesicle caught in the 
course of such an ovarian abortion. While Hewetson and Jordan-Lloyd 
conclude that the case is one of primary implantation in the substance 
of the ovary, they are inclined to the view that the ovum, either fertilized 
or unfertilized, reached the surface of the ovary, but being prevented, 
possibly by adhesions from reaching the Fallopian tube, burrowed 
back, as it were, into the substance of the gland. While the possi¬ 
bility of such an occurrence cannot be excluded, the case fits in with 
the other recorded cases, and with the present specimen much better if 
considered as a further stage of burrowing from within. The conditions 
of imbedding revealed in the early ovum described in the first paper 
embodied in this publication—its complete inclusion, the excessively 
minute size of the sealed point of entrance, indicating the very early 
stage at which imbedding occurs—seem to remove the difficulties, which, 
on account of the continuity of the thin layer of stroma intervening 
between the gestation sac and the corpus luteum, impelled Hewetson 
and Jordan-Lloyd to interpret the appearances in their case as due to 
burrowing of the ovum into the ovary from without. 
The factors of ovarian pregnancy appear, in short, to be fertilization 
