of Edinburgh , Session 1870-71. 
375 
exert a force in labour of 54 lbs., that this force is employed in 
dilating the cervix and rupturing the membranes, and that it can 
or does effect little more. 
Now, it appears to me that Haughton limits far too much the 
use of the power of the uterus. I have no doubt that the uterine 
efforts not only dilate the cervix and rupture the membranes in 
most cases, but also do, in most cases, perform the chief part of 
the work required to bring forth the child. Although I do not 
coincide with Haughton in his reflections on the economy of 
muscular power, I shall not discuss the point therein raised. Yet 
I cannot avoid saying that, in the present instance, his own state- 
ments invalidate his reflections, for he asserts that the uterine 
muscle has three times the amount of muscular power required to 
do the work demanded of it. In endowing the uterus with this 
great power, Haughton, in my opinion, furnishes conclusive evi- 
dence against his own view as to the use of the contractions of the 
uterus. For I am sure that the great mass of births, even in 
difficult labours, including only the most difficult, is effected by a 
force less than what Haughton ascribes to the uterine muscle 
alone. I am satisfied that the whole combined powers of labour 
seldom reach above 50 lbs., while Haughton gives the uterus alone 
a power of 54. 
I do not say Haughton is wrong in supposing that the uterus 
can exert a force of 54 lbs. On the contrary, I have no reason to 
doubt it. But I am sure that while easy labours require for their 
whole work a force scarcely exceeding the weight of the child, 
only a few difficult labours require for their whole work a force 
exceeding 50 lbs. 
Every accoucheur knows to some degree of exactness the force 
which is required to restrain the forward movement of the child 
when there is no special resistance to its advance. This power I 
have measured approximatively by dynamometrical experiments, 
and I find it to be at the most 50 lbs., — a power less than what 
is ascribed by Haughton to the unaided uterus. In other words, 
the uterus and voluntary muscles combined, stimulated to violent 
effort by insuperable temporary resistance, exert a force greater 
than is required to complete the labour; yet this force is generally 
much less than 50 lbs., and possibly never exceeds it. 
