SOME ACCIDENTS OF PREGNANCY. 57 
In the sporadze 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 zzfectzous 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 sforadic 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 zfectzous form may be transmitted, 
either directly, or through the intervention of certain 
media, as infected feces, 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 introduction 
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 
