PATHOLOGY OF PREGNANCY AND PARTURITION 431 



of the urachus causes the urine also to drain into the amniotic 

 cavity. Thus hydramnios is the only condition found in human 

 beings. In the domestic animals, however, dropsy both of the 

 amnion and of the persistent allantois may take place, and the 

 urine drain into the latter sac owing to the urachus remaining 

 open till birth. 



Development of the fertilised ovum outside the uterus, 

 either in the ovaries, Fallopian tubes, or in the peritoneal cavity, 

 occurs in animals as in man, though with important differences. 

 In the human subject extra uterine gestation, though rare, is 

 always a true primary condition ; in animals, such as rabbits, 

 hares, swine, dogs, sheep, cattle and horses, besides this there is 

 a false extra-uterine gestation constituting the majority of the 

 cases, due to rupture of the uterus and implantation of the foetus 

 in the peritoneal cavity, where it may, or may not, undergo 

 further development. 



CEdema of the legs and external genitals constitutes one of 

 the most frequent symptoms of pregnancy in the human female. 

 This oedema is often associated with varicose veins, which per- 

 sist in a slighter degree after parturition. A similar oedema of 

 the hind-legs and udder is common in pregnant mares and 

 cows, but varicose veins are not mentioned in works on veter- 

 inary obstetrics, either because they do not occur, or because 

 their presence is concealed by the animal's hair. 



Nervous complications of pregnancy peculiar to women are 

 fainting, hysterical convulsions, and eclampsia due to renal 

 disease. It cannot be decided whether pregnant animals, like 

 women, suffer from neuralgic pains of various kinds, as there 

 are no means of recognising such a condition. It is certain, 

 however, that mares and cows often experience false or prema- 

 ture pains while the os uteri is closed and the udders still 

 flaccid ; cows and goats suffer from cramp of the cervix uteri 

 without dilatation of the os, and also from premature pains and 

 distension of the udder as a result of old cicatrices and thicken- 

 ing of the walls of the cervix. As might be expected these 

 premature pains often result in abortion. 



In human beings the term abortion is used to mean expul- 

 sion of the foetus during the first three months ; this condition 

 is due either to extreme excitability on the part of the mother, 



