184 THE CREAMERY PATRON'S HANDBOOK. 



not thrive well after aborting, some continue to discharge a fetid substance 

 from the genitals for a considerable length of time, and others will not breed, 

 no matter how often they are served in their regular periods of heat. 



Can I do anything to stop the cows from aborting, or to prevent the 

 disease from going through my entire herd? These complaints have be- 

 come quite general in dairy districts. 



Epizootic abortion has been known to exist permanently on some 

 farms, and to cause for many years serious pecuniary loss. 



This enzootic or epizootic character of an accident which is usually 

 produced by trivial causes, such as contusions, acute febrile diseases, cold, 

 poisoning, ingestion of tainted or mouldy food, and unwholesome drinks, 

 indicates that it is sometimes of an infectious nature. 



As long as its pathologic agent is not known, epizootic abortion must 

 be classified in the group of specific diseases. 



The infection seems to be produced by a "stable miasma." It has 

 been demonstrated that the virulent agent exists in the discharge of the 

 genital canals and in the foetal fluid; by the intermediation of these liquids 

 healthy animals may be affected. By introducing into the vagina of healthy 

 cows the vaginal mucus of a cow which had just aborted, abortion has been 

 produced in from nine to twenty-one days after inoculation. 



Experience has sufficiently demonstrated that the disease is eminently 

 contagious, and that it may be transmitted directly or by certain inter- 

 mediaries through the vaginal discharge, litter, by persons who are charged 

 with the care of the patient, by owners or veterinarians (after the extrac- 

 tion of the placenta from an animal which has aborted) and even by breed- 

 r ing males. 



The transmission of the disease from a cow which has aborted to its 

 immediate neighbors is the rule, and it is much favored by the existence, 

 behind the animals, of a trench where the vaginal discharge and excrementi- 

 tious matters accumulate. 



The causes to which the disease was formerly ascribed tainted food, 

 rainy years, bad quality of food, permanent stabling, close breeding, etc, 

 are but predisposing conditions. By weakening the organism they facilitate 

 the introduction and pullulation of the infectious matter. 



Epizootic abortion may establish itself in the best kept stables a fact 

 which proves that uncleanliness plays but a secondary etiological role. 



Nothing positive is as yet known as to its pathology. It is very probable 

 that the infectious agents penetrate into the womb through the vagina and 

 as, like specific agents in other diseases, their pullulation in the foetal en- 

 velopes determines sufficient alterations to lead to abortion. The process 

 is, no doubt, propagated from the covering to the foetus, as the death of 

 the latter seems to demonstrate antepartum in most cases of epizootic 

 abortion. 



At the present time it is not known whether the virus may penetrate 

 into the blood through the respiratory or intestinal tracts. Some authorities 



