532 OBSTETRICAL OPERATIONS. 



equal to that of the pulleys, windlass, or capstan ; that its action is 

 based on mechanical laws ; that the traction it produces is so gentle, 

 slow, and regular, that it is without danger for the mother ; that its 

 employment altogether leaves behind all the other means used for the 

 production of the necessary counter-extension in fcetal extraction ; that 

 the collar transmits, in a regular manner, and to the whole of the 

 inferior and posterior parts of the maternal pelvis, the pressure it 

 receives from the female screw ; that this pressure, disseminated over 

 the entire hind-quarters of the female, is proportionately less severe and 

 painful during traction of a given intensity. ' 



Many more references could be given to other very competent 

 authorities in favour of mechanical over manual traction ; but the evi- 

 dence may be summed up by stating that mechanical traction is prefer- 

 able to that produced by manual power, inasmuch as it is slower, 

 more regular, its action is more sustained, and it is more powerful and 

 efficacious, without imposing increased strain on the parent or foetus. 

 Manual traction is unsteady and jerking, especially when several men 

 are pulling ; all the men do not pull alike, or at the same time ; there- 

 fore even during traction, however steady it may aim to be, the strain 

 varies, as men soon become fatigued; whereas the machine can maintain 

 the traction for any length of time without increasing or diminishing it. 



One of the objections urged against machine traction is that its direc- 

 tion cannot be so easily varied upwards, downwards, or to one side or 

 the other, as manual traction. But this is a very trifling objection, 

 and it may be nearly, if not altogether, overcome by making assistants 

 press against the cord or cords, so as to give these the necessary 

 direction. 



"When powerful traction is required, whether it be manual or 

 mechanical, great attention is necessary in guiding the foetus through 

 the genital canal, so as to prevent injury to the parent. The traction 

 should cease in the intervals between the labour-pains, and the efforts 

 ought not to be continuous ; the animal should be allowed intervals of 

 rest, and time be given for the genital canal to dilate and adapt itself 

 to the passage of the foetus. Severe and injudicious traction may be 

 productive of the n:iost serious results. Even when the operation is 

 nearly terminated, care will be requisite in order to prevent inversion of 

 the uterus. Tliis accident may be obviated by careful manipulation, 

 and abundant injection of emollient fluids. 



CHAPTEE V. 

 Embryotomy. 



Embryotomv, or emhri/ulcia, is the name given to every operation which 

 has for its object the reduction in volume of the foetus at parturition, by 

 mutilating or dividing it ; so as to allow it to be extracted by portions 

 when it cannot be delivered whole. It is a generic term for a number 

 of operations very different in their character, and performed on the 

 foetus either while it is wholly retained in the uterus, or more or less 

 engaged in the genital passage. 



The operations may be practised on various parts of the young 

 creature — head, limbs, or body — and they facilitate the removal of one 



