SOME ACCIDENTS OF PREGNANCY. 57 



In the sporadic form, one pregnant animal gives- 

 birth to a foetus, some days, or perhaps months, before 

 the normal period, and there the disease stops. 



In the infectious form, one animal after another is- 

 affected, it may be for years, till it seems impossible to- 

 get any animal to carry her young the full period of 

 gestation. 



The disease is most common amongst cattle, much 

 less frequent in Mares. It has also been observed in^ 

 the Sheep and Goat. 



The causes of the sporadic form are : excitement,, 

 sudden fright, either at pasture or in the stable ;. 

 injuries by being thrown down, large doses of 

 medicine, especially purgatives ; injudicious feeding, as- 

 large quantities of cold food in cold weather; and 

 some varieties of pasture are believed to cause it. 



The disease may appear, or take place at any time 

 during pregnancy. 



It is now recognized by the most competent 

 authorities, that the infectious form may be transmitted, 

 either directly, or through the intervention of certain 

 media, as infected faeces, urine, or litter; by attendants 

 on the animals which have aborted ; by the veterinary 

 attendants, or even by the male animal in the act of 

 coition. Abortion has been induced by the introductiom 

 into the vagina of pregnant cows, mucus from that of 

 animals that had aborted accidently, also by inoculating- 

 the purulent vaginal discharge from a cow just aborted,, 

 and the matter obtained by scraping the surface of the- 

 chorion expelled by another animal which had likewise 

 "lost" her calf. Whether the infective material finds 



