564 DISEASES OF THE HOESE. 



animal fails to pick up one of the hind feet as freely as the other, 

 or both may become affected at the same time, at which time knuck- 

 ling is a common symptom. Labored breathing is occasionally noted. 

 When the paralysis of the hind limbs starts to appear the disease 

 usually progresses rapidly. The horse goes down, is unable to rise, 

 and dies in a short time from nervous exhaustion. The appetite 

 usually remains good up to the last. 



Although a case of dourine may now and then recover, as a rule 

 the disease is present in the latent stage. Bad weather, exposure, 

 insufficient feed, and complicating diseases like influenza, distemper, 

 or in fact any condition which tends to lower the vitality of the ani- 

 mal, may hasten the termination of the disease. 



Diagnosis. — The complement-fixation test furnishes by far the 

 most reliable means of diagnosis and is especially valuable in a 

 chronic affection of this character, when the symptoms manifested 

 are variable and frequently so obscure as to escape observation. This 

 is a laboratory test requiring special facilities and the services of a 

 trained bacteriologist. 



Treatment. — Little benefit can be obtained from medicinal treat- 

 ment, nor is such treatment desirable in this country, where the 

 disease has existed only in restricted areas, and where sanitary con- 

 siderations demand its prompt eradication. 



INFECTIOUS ABORTION IN MARES. 



Infectious abortion (also known as contagious abortion, epizootic 

 abortion, enzootic abortion, slinking of colts) is a disease of mares 

 which from a specific cause results in the premature expulsion of 

 the fetus and its membranes from the uterus. It is characterized by 

 an inflammatory condition of the female reproductive organs. 



The contagious nature of the disease had not been recognized 

 until recently, the disease being principally attributed to various 

 conditions, such as traumatic influences, various infectious diseases, 

 spoiled feed, drugs, and other factors. Ostertag was the first to 

 study premature births in mares, attributing as the cause of the same 

 a streptococcus, which he was supposed to have been able to use 

 successfully in artificially producing abortion, either by inoculations 

 or feeding. His findings could not be substantiated by other inves- 

 tigators. 



The earliest appearance of the disease in this country was in 1886, 

 at which time it caused considerable damage to the horse-breeding 

 industry in the Mississippi Valley. Smith and Kilbourne investi- 

 gated an outbreak in Pennsylvania in 1893, at which time they 

 incriminated another germ belonging to the paratyphus B group 

 as the causative factor of the disease. These findings have been sub- 



