136 BOVINE OBSTETRICS 



Definition. — By hydrallantois is understood an extraordin- 

 ary accumulation of fluid in the sac of the allantois, dilating 

 the latter greatly and increasing the dimensions of the uterus 

 to such an extent that disturbances may ensue. As much 

 as 170 1. have been found (Hess). 



JEtiology — Hydrallautois as a disease per se, depends on 

 disturbances of the foetus or its annexes without necessarily 

 involving any organ of the mother from an etiological point of 

 view. In many cases the only cause is found in the fcetal 

 envelopes. 



In hydrallautois, most authors — which is also my experi- 

 ence — have found normally developed calves, and no dropsical 

 ones (Hess, Kammermann, Kronburger, Tapken). 



Franck insists that hydrallautois and dropsy of the cavities 

 of the body of the mother are often associated. Kamm.ermau 

 also looks upon hydremia of the female as a cause of hydral- 

 lantois. This may have been observed in some instances, but 

 in the majority of cases the cause does not exist with the 

 mother. 



The increase of allantoic fluid may take place in two ways: 

 first, by increase of fcetal urine; and, secondly, by transuda- 

 tion. The former cannot be very great, on account of the 

 limited activity of the foetal kidneys. At the same time, but 

 little is known about foetal kidney diseases in animals. 



The second course is of greater importance — the transu- 

 dation, following circulatory disturbances of the placental 

 blood vessels. According to Kitt, hydropsioal changes of the 

 chorion depend mainly on a stasis hyperemia started by 

 torsion of one or more portions of the fcetal membrane, while 

 other parts still adhering to the placenta materna and in a 

 normal state supply the embryo with nourishment. 



Kitt states that in ruminants crowding of the foetal mem- 

 branes and torsions are very liable to occur, as the chorion 

 forms fold physiologically, since the embryo and its mem- 

 branes are too long for the uterine cavity during a certain 

 period of gestation (Bonnet). 



Hess observed, in a post mortem of a cow goffering with 



