concerning Animal Impregnation 189 
discharged their contents before either of these periods. The 
examination of these at the usual time, proved that the actions 
of these parts suffer no interruption by a division of the tube 
made after the rudiments of the foetus have been conveyed 
into the uterus ; for there were corporea lutea in both ovaries, 
and foetuses in both cornua uteri. 
These experiments I think overturn (as far as experiment 
can) every argument which has hitherto been adduced to sup- 
port the hypothesis, that the affusion of the semen on the 
ovaries, either in a sensible form or in that of aura seminalis 
is essential to impregnation : for if the ovaries were suscep- 
tible of their proper excitement only by the contact of semen, 
by what accident has it happened that the effects of that ex- 
citement are not more obvious and further advanced in those 
experiments, where nothing was done to intercept its course 
for forty-eight hours, than in those where all. communication 
between the uterus and ovary had been cut off before the 
means for impregnation had been employed ? We should ex- 
pect in the one case to find the full effects of impregnation, and 
in the other no traces of it would be seen ; instead of which, 
the procreative actions are no further advanced where there 
has been an opportunity for the passage of the semen, than 
in those cases where the passage has been impossible. But if 
we defer the mutilation until the ovary has perfected its work, 
which it does in a rabbit in something more than fifty hours 
from the approach of the male, then the generative process is 
not disturbed, and the evolution of the foetus goes on in the 
usual manner ; for now all the different parts of the uterine 
system being in a condition to act, each performs its peculiar 
office. 
