PATHOLOGY OF PREGNANCY AND PARTURITION 435 



the human subject, have no greater effect on the course of 

 parturition when they are observed in animals. The length of 

 the cord is, however, in both cases of more importance. If it is 

 too short the entry of the head into the true pelvis will be de- 

 layed, and often there will be a separation of the placenta and 

 consequent haemorrhage. If it is too long it may, during the 

 period of gestation, become twisted round the neck or other 

 portion of the body of the foetus, and so delay parturition, or 

 in human beings it may become prolapsed ; if the cord cannot 

 be replaced, prolapse constitutes a serious complication, and may 

 lead to the death of the child during parturition. Lacerations 

 of the cord during labour are much more dangerous to the 

 human child than to young animals, unless they are at once 

 ligatured. This difference depends on the behaviour of the 

 umbilical vessels, which in the case of animals become sealed 

 immediately after a laceration, whereas in the case of human 

 beings, unless a ligature is applied, a dangerous haemorrhage 

 occurs. 



It is obvious that both in human beings and animals unusual 

 rigidity of the external os uteri, and superficial or still more 

 deep-seated strictures, will cause serious obstructions to the 

 course of parturition. In women, mares, cows and bitches a 

 narrowing of the vagina or vulva, due to antecedent wounds or 

 inflammation, may cause rupture of the uterus of the neighbour- 

 ing large blood vessels or the vagina, unless operative assistance 

 is promptly rendered. 



In women it may happen in the second or third stage of 

 labour that, if traction is made on the cord while the placenta 

 is still firmly attached, the placental site becomes inverted and 

 dragged through the os, until in the most extreme cases the 

 entire uterus is turned inside out and pulled out through the 

 vulva. In domestic animals similar causes lead to inversion 

 and finally to prolapse of the inverted uterus. In ruminants, 

 with their multiple placentas, the tendency to prolapse is much 

 greater than in animals with single or widely spread placentae ; 

 "especially as in the first -named animals the fusion of the 

 foetal and maternal portions of the placenta is much more in- 

 timate and the method of its detachment is quite different from 

 that which obtains in the others " (Franck). 



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