380 Proceedings of the Payed Society 
with a view to the present question. They are explicable in more 
ways than one, and an illustrative statement is, for my present pur- 
pose, quite sufficient. Every experienced accoucheur has seen 
cases where voluntary increase of bearing down has sufficed to 
expedite labours, which, if the women had been left in a sleepy, 
lethargic condition, might have been protracted for an indefinite 
length of time. 
There can be no doubt that the uterus is a very powerful 
agent in expelling the foetus from its cavity into the world — 
that it is not the sole agent, and that it is assisted by the action 
of the voluntary muscles. Though I have not proved absolutely 
that the uterus is the chief agent in the performance of this func- 
tion, yet I have no doubt that it is so; and I think that the 
arguments I have adduced give this belief of the profession the 
highest degree of probability. This belief does not imply that 
the aid afforded by the voluntary muscles is inconsiderable or 
unimportant. It only renders it quite incredible that while the 
power of the uterus is 54 lbs. that of the voluntary muscles can 
be 523. 
III. Haughton’s conclusion, on which I wish last of all to 
comment, is, “ that, on an emergency, somewhat more than a 
quarter of a ton pressure can be brought to bear upon a refrac- 
tory child that refuses to come into the world in the usual manner.” 
In my work entitled “ Researches in Obstetrics,” to which Pro- 
fessor Haughton refers, I have discussed carefully, but briefly, 
this point, and announce the conclusion that the comparatively 
small figure of 80 lbs. gives the highest power of labour ; and I 
quote Joulin, who estimates it at somewhat above 100 lbs. I do 
not deny that in exceptional circumstances a few pounds above 80 
may be reached, but I feel pretty sure that seldom in the history 
of woman has the figure 80 been attained, whether on an emer- 
gency or not. This conclusion is arrived at by experiment and 
observation— experiments on the force required to pull a child 
through a contracted brim of pelvis, observations of the force used 
to complete a difficult labour, which nature, in its most violent 
throes, has failed to accomplish. 
Every accoucheur will, I suppose, readily admit that, in a case 
