INFECTIOUS ABOETION". 197 



The disease occurs at all periods of gestation after tlie third 

 month, and in the same animal at a later stage in each suc- 

 ceeding pregnancy, until at length the foetus is carried its full 

 term, if the mother has not become sterile. The calf is generally 

 dead at birth, but in some instances it is born alive ; it is, 

 however, generally in bad health, emits a peculiar lowing, and 

 after the third day is attacked with diarrhoea, which rapidly 

 terminates fatally. 



Abortion succeeding to fright or injury may become infectious ; 

 lience arose the supposition that it was due to sympathy, and 

 thus spread from cow to cow in a byre. It is true that there 

 is often great excitement amongst the cows in a byre during 

 and after abortion by one of them, and that there is also often a 

 peculiar odour emitted by both mother and offspring. It has 

 also been attributed to ergotism, mouldy food, cold, contusions, 

 unwholesome drinks, &c. All these may be predisposing 

 causes, but it is now fairly demonstrated by Nocard and others 

 that the virus exists in the discharge from the mother, and in 

 the uterine fluids, and that by the introduction of these fluids 

 from an aborted cow into the vagina of healthy ones abortion 

 will be induced in from nine to twenty days. — (Brauer.) Lehnert 

 thus produced it in twelve to twenty days, and Trincherra 

 obtained a purulent vaginal catarrh and abortion in from nine 

 to nineteen days. Inoculation matter obtained by scraping the 

 surface of the chorion of an aborted cow produced a like result. 

 The transmission from cow to cow is most probably by im- 

 mediate contact of the material with the genitals of cows in the 

 same byre, the discharges being conveyed by the groop or 

 drain which is immediately behind the cows in all byres. 



It can easily be understood how the virus thus conveyed 

 contaminates the tails and hind extremities of the cows when 

 recumbent, and how easily natural inoculation is thus effected 

 by the movements of the tainted tails, more especially if the 

 drain leads from the aborted to the healthy ones. 



Nocard states that abortion takes its origin in diverse germs 

 met with in the uterus of aborted cows, but which are never 

 found in healthy ones. These germs are also present in the 

 amniotic fluid in the alimentary canal of aborted calves, as well 

 as in the medulla oblongata of those which during life give 

 utterance to the peculiar lowing sound ah'eady referred to. 



