INFECTIOUS ABORTION. 199 



4 Also cases of sterility which are consecutive to abortion 

 can be explained by the acid reaction of the uterine mucus, in 

 which the microbes thrive, the spermatozoa not being able to 

 preserve their vital properties except in alkaline elements. 



5. Epizootic abortion seems indeed to be a microbic disease 

 of the foetus and its envelopes, but one which does not affect the 

 mother.— (Revbet, 1889.) 



This form of abortion, while prevalent in certain districts, is 

 unknown in others, but it may be conveyed from one district to 

 another by the introduction of cattle from an infected area. 

 Upon this point a mass of evidence is adduced by Sand,^ Eoyal 

 Veterinary College, Copenhagen, who hints at the conclusion 

 that abortion, independently of its isolated sporadic occurrence 

 in widely separated districts, occurs in an epizootic or enzootic 

 but non-contagious form from accidental causes, such as musty 

 food, bad or cold water, insanitary surroundings, stall feeding, 

 and in-and-in breeding. 



In addition to the evidence as to its spread by the intro- 

 duction of affected cows, proof is brought forward establishing 

 the fact that the disease is also introduced by using bulls from 

 an infected herd, and instances are recorded where bulls have 

 been known to suffer from severe preputial inflammation after 

 having served diseased cows. It is also stated that the vaginal 

 mucous membrane is reddened, permeated throughout with cord- 

 like swellings, and showing numerous small reddish-yellow or 

 reddish-brown nodules. There are also small eruptions about 

 the root of the tail, anus, and vulva. These symptoms, how- 

 ever, are not common, but there is often a chronic purulent 

 discharge from the vulva. 



As already stated, a first abortion occurs earlier than later 

 ones, often at the third or fourth month, whilst the period is 

 gradually extended in later ones, and the explanation seems to 

 be that the microbes gradually lose their virulence, until finally 

 the animal has immunity. This fact is very important, and 

 contradicts the generally adopted method of eradicating the 

 disease, namely, that of disposing of aborted cattle and replacing 

 them with fresh ones, which in their turn become affected and 

 maintain the continuance of the disease in a herd ; whereas, if 

 aborted cattle are kept, only those proving sterile being disposed 



^ See Infectious Abortion, by Jno. A. W. Dollar, — Veterinarian, June 1893. 



