INFECTIOUS DISEASES. 565 



sequently substantiated by many investigators abroad, as well as in 

 this country, notably so by De Jong, Dassonville, and Riviere, and by 

 Good and Meyer. More recently very valuable information was 

 contributed to our laiowledge on this disease by Schofield, of Canada, 

 especially with regard to the biological tests for diagnosis. Good 

 suggested "BacUlus dbortivus equinus" as the name for the specific 

 organism. 



The causative agent of this disease is not identical with the germ 

 causing abortion in cattle. It exerts its action, however, in a similar 

 manner, and appears to have, under certain conditions, a predilec- 

 tion for the genital organs of the mare, where it induces certain 

 morbid changes whereby a premature expulsion of the fetus is the 

 result. The germ is usually present in the fetal membranes and also 

 in the aborted fetus. Mares may harbor the infection without dis^ 

 closing any apparent ill eflfects. It appears to exert its influence 

 mainly upon the female genital organs, where it may induce an in- 

 flammatory condition of the uterus. 



The infected animals may carry the fetus through the normal 

 period of pregnancy, giving birth to either a normal or a weak colt, 

 or again abortion may take place at any time during pregnancy, 

 mostly, however, from the sixth to the ninth month. 



Symptoms. — ^The symptoms suggestive of abortion are frequently 

 entirely absent. At times the abortion may be ushered in by symp- 

 toms of colicky pains, restlessness, and periodical straining; these, 

 however, are by no means constant, especially if the abortion takes 

 place in the early months of pregnancy. The genital organs are 

 usually swollen, showing a mucous discharge. Immediately before 

 abortion the symptoms are more aggravated. Following abortion the 

 discharge is more characteristic, being of a dark-brown color, some- 

 times even bloody, and contains streaky or flalcy pus. The fetal mem- 

 branes in all cases are not expelled with the aborted fetus, but there 

 is a tendency toward retention of these membranes, which frequently 

 has serious consequences upon the health of the animal. At times 

 it becomes necessary to resort to manual removal of the afterbirth, 

 and the inflammation of the uterus and a chronic discharge usually 

 follow such conditions. The expelled fetuses, as a rule, die soon 

 after the abortion, and if the expulsion has taken place at a time close 

 to its full term the fetuses are usually poorly developed and subject 

 to various kinds of digestive and septic disorders. The fetuses do not 

 disclose any particular abnormal appearance on external examin- 

 ation; in many cases, however, the post-mortem examination reveals 

 inflammatory changes of various organs. 



The method of infection has not yet been satisfactorily established ; 

 nevertheless it is essential that we consider as the principal mode of 

 infection the ways which have been proved for the contagious abor- 



