J 33 
THE RELATION OF VESICULAR MOLE TO 
CHORION CARCINOMA 
By J. EFFIE PROWSE, M.D., ChB., Glas. 
ETHEL BOYCE FELLOW IN GYNECOLOGICAL PATHOLOGY, UNIVERSITY COLLEGE, LIVERPOOL 
BEFORE entering upon a discussion of the pathology of vesicular mole and its 
frequent sequaela, chorion carcinoma, it is necessary to review, somewhat in 
detail, the opinions at present held concerning the development and structure 
of the chorionic vesicle. 
Much light has of recent years been thrown on this difficult subject by the 
discovery of several observers of certain very early ova. 
Foremost among these is Peters, of Vienna, who, in 1899, secured a human 
ovum of only two or three days' growth, measuring i - 6 by - 8 and "9 millimetres in 
diameter ; so far as is known the youngest ovum on record. The description of this 
and of the way in which it was embedded in utero has, to a great extent, revolutionized 
the hitherto widely accepted views of human placentation. 
Of the many theories held concerning the mode of attachment of the fertilized 
ovum to the uterus, the following may be mentioned : — 
1. That the ovum, having passed through the first stages of segmentation 
immediately following fertilization, becomes speedily embedded in the soft and thick- 
ened mucous membrane, which is soon reflected completely over it, the ovum coming 
to lie in a cavity shut off from the general cavity of the uterus. 
2. That some abrasion of the uterine mucosa was essential to the formation 
of a suitable resting-place for the ovum. 
3. The opinion expressed by Berry Hart that possibly the ovum grafted 
itself on the connective tissue of the uterus which had been exposed by the removal 
of the mucous membrane during menstruation. ' Pfluger first suggested that the 
human ovum can only be implanted on connective tissue, and thus cannot develop in 
the healthy tube or cervix, and the view has been strongly upheld by Lawson Tait. 
This theory accounts for the frequency of conception just after menstruation, and for 
the fact that tubal pregnancy is usually preceded by disease destructive of the tubal 
epithelium, but it does not account for those cases of tubal gestation with no previous 
tubal disease, nor for the occurrence of uterine gestation remote from menstruation, 
as during lactation and pathological amenorrhoea.' (Fothergill). 
