POWER EXERTED IN THE FUNCTION OF PARTURITION. 651 



mum of the contractile power of the uterus ; for it is necessary to take into account 

 the accessory contingent furnished by the abdominal muscles, which in these 

 instances was awanting. But as this force has not a direct action, it is probable 

 that its actual product scarcely rises above a few kilogrammes." 



Having had extensive and varied experience in the use of the forceps in 

 difficult labours, and having also made some rough experiments with the 

 dynamometer, to ascertain the power I have applied by the instrument, I regard 

 M. Joulin's estimate of a hundredweight as the maximum force of the partu- 

 rient function as far too high. I do not deny that, in very rare cases, such a force 

 may possibly be produced ; but I am sure that it is nearer the truth to estimate 

 the maximum expulsive power of labour (including, with the uterine contrac- 

 tions, the assistant expulsive efforts) as not exceeding 80 lbs. 



At present, I can divine no method of arriving at an estimate of the expulsive 

 power of ordinary labours, except the following; and I must guard myself from 

 being supposed to recommend its use, in the meantime at least. A fine tube, 

 filled with water and of resisting material, may be introduced into the small pool 

 of liquor amnii which remains after the rupture of the membranes filling up the 

 spaces otherwise vacant on the anterior aspect of the foetus. This tube should 

 be provided with an aperture at its uterine end ; it should be curved, so that 

 when introduced it may lie easily in the pelvis, occupying the least possible space, 

 so that no unnecessary resistance be offered to the advance of the foetus ; its wall 

 should taper to either side, a. cross section of it having a long pointed fusiform 

 outline, in order that its presence may not produce on either side of it a channel 

 for the running off of the pool of liquor amnii ; lastly, its external end should be 

 in communication with a column of mercury in a vertical tube, enclosing a 

 column of air under only ordinary barometrical pressure. During the pains the 

 rise of the mercury in the tube may be measured, and calculations from these 

 measurements might be made identical with those already given in an earlier 

 part of this paper. By this means, if successfully applied, the force of any labour 

 may be exactly known. And it is scarcely necessary even to suggest how im- 

 measurably valuable to the accoucheur such an estimate would be, substituting, 

 as it would, an experimentally accurate statement of awful importance for the 

 vague notions at present relied on, even when the wisest and most experienced 

 practitioner lends his counsel. 



I have already expressed my opinion as to the great practical importance of 

 the inquiry entered upon in this paper. Although it is, as yet, far from com- 

 pleted, there is enough demonstrated to enable Dr Slop, if he have an opportu- 

 nity, to cast ridicule on the father of Tristram Shandy, who, founding on the 

 statements of Lithopcedus Senonensis, asserts, that the force of a woman's efforts 

 is, in strong labour-pains, equal, upon an average, to the weight of 470 lbs. avoir- 

 dupois, acting perpendicularly upon the head of the child ! ! 



VOL. XXIV. PART III. 8 U 



