i52 THOMPSON YATES AND JOHNSTON LABORATORIES REPORT 
Quoting from Cullen's Cancer of the Uterus, we find that — 
One case followed a tubal pregnancy. 
One case followed a miscarriage at the sixth month. 
Twelve cases followed an abortion. 
Seventeen cases followed a labour at term. 
Twenty cases followed the discharge of a hydatidiform mole. 
' In those cases in which abortion had occurred, two of the women had 
previously expelled hydatidiform moles. Thus in twenty-two (43*3 per cent.) of 
the cases there was a history of the expulsion of a vesicular mole some time prior 
to the appearance of the disease.' 
Other writers give even a higher percentage than this, and, from my own 
observations, I believe it is probable that in all cases, whether preceded by a mole or 
not, changes take place in the epithelium of portions of retained placenta, which are 
the starting point of the disease, exactly similar to those which occur in vesicular 
mole. As previously mentioned, I have, in two or three cases, found evidences 
of such changes in pieces of retained placenta which have been removed by the 
curette. 
It has been objected by Eden that there is no evidence that pieces of 
placenta go on growing after the death of the foetus, but when it is remembered that 
the villi of the early ovum, and also in vesicular mole, are dependent for their 
nutrition on the maternal blood in which they lie, and not on the foetal supply, 
it is easy to understand how the chorionic tissue can go on growing long after 
the death and absorption of the foetus. 
As an important predisposing cause, the general condition of the patient 
must be considered. In a large number of the cases recorded there have been dis- 
turbances of the general health during the preceding period of pregnancy. One 
symptom has been specially noted, viz., pernicious vomiting. This, in many cases, 
has occurred in the early months and led to premature emptying of the uterus. 
Other cases have developed neurotic tendencies — apprehensions as to the result of 
the pregnancy, persistent headaches, perverted mental conditions, and in one case 
maniacal attacks are said to have occurred. 
In those cases where the disease is preceded by the expulsion of a vesicular 
mole, the patients are invariably anaemic and emaciated from frequent blood loss, and 
interference with the digestive functions. 
Symptoms 
These, stated briefly, are sudden and severe attacks of haemorrhage, occurring 
within a few days or weeks of the termination of the pregnancy, rapid emaciation, 
profound anaemia, an intermittently high temperature, and all the other accompani- 
ments of septic intoxication. 
