Infectious Abortion of the Cow 503 



more or less fetid. Large quantities of this discharge may ac- 

 cumulate in the uterus and later be expelled at intervals, or the 

 flow may be virtually continuous. 



Generally the aborted fetus is dead, but not greatly, if at all, 

 decomposed when expelled. Rarely the fetus is born alive. If 

 dystocia occurs the fetus soon decomposes. The afterbirth is 

 usually more or less discolored, there is edema a^jl injection of the 

 chorion, and between the cotyledons there is frequently seen a 

 muco-purulent exudate. When a cow has once aborted and is 

 bred soon afterward, it is claimed that she is very liable to again 

 abort from the infection which caused the prior abortion and has 

 persisted in the uterus during the entire period. This has not been 

 well established. If the bacillus is already present in the uterus 

 at the time of copulation, it would seem more probable that it 

 would destroy the life of the spermatozoa and of the ovum even* 

 before impregnation took place. Should the ovum and sperma- 

 tozoa escape such a fate, it would appear probable that abortion 

 would occur so early during gestation that the expulsion of the 

 very small embryo would pass unrecognized. 



Diagnosis. Hutyra and Marek, and other writers, place great 

 diagnostic value upon the swelling of the vulva and the genital 

 discharge, which usually occur two or three days prior to the ex- 

 pulsion of the fetus. If the reliability of these symptoms can be 

 clearly established, they become of fundamental importance in ref- 

 erence to the control and eradication of the disease by leading 

 to earlier diagnosis of the presence of the infection in a given 

 individual. When the abortion has occurred, some authors 

 claim that the existence of a fibrino-purulent exudate upon the 

 chorion speaks for the infectious nature of the disease, but it has 

 apparently not been fully determined that the infectious abortion 

 can thus be safely differentiated from that occurring from other 

 causes. 



Once the disease has become established in a herd, the best 

 proof of its character is the gradual and more or less rapid spread 

 of the affection from cow to cow. In many cases this is ex- 

 tremely rapid when the disease assumes a highly virulent type, 

 whereas in other instances, when the disease has lost its virulence 

 in a community or stable, the spread is very much slower and 

 may be spontaneously confined to a very small percentage of the 

 pregnant cows in the herd. Hutyra and Marek, citing Cagny, 



