General Infections of the Genitalia of Sheep and Goats 719 



The infections which may cause abortion are undeter- 

 mined and probably quite varied. The B. abortus is capable 

 of multiplying within the uterine cavity, as has been demon- 

 strated abundantly by various investigators. The experi- 

 mental inoculations have not shown, however, that it does 

 or can with any certainty cause a pregnant ewe to abort, 

 although some conclude that, if the B. abortus is present, it 

 can cause abortion. It is a difficult matter to prove. 



The organism most frequently alleged to be the cause, or 

 the most common cause, of abortion in the ewe is a vibrio or 

 spirillum apparently identical with the vibrio previously de- 

 scribed as associated with certain outbreaks of cattle abor- 

 tion. The belief that the spirillum causes the abortion in 

 those cases where it is recognized is based fundamentally 

 upon its recognition in abundance in the stomach of the fetal 

 cadaver. This constitutes valuable presumptive evidence. 



McFadyean and Stockman 1 have given the vibrio the 

 most extended study yet published. The organism is S- 

 shaped or spiral, 1.5 to 3 microns in length. It grows in 

 various culture media. The colonies present an appearance 

 like B. abortus. The living organisms are highly motile, 

 moving rapidly in a spiral. McFadyean and Stockman be- 

 lieved they had proven by experimental inoculation that the 

 vibrio they described caused the abortions. In many cases 

 of abortion following natural exposure, the vibrio could not 

 be found. In some cases putrefactive bacteria may have 

 destroyed or veiled the vibrios ; in other instances this did 

 not appear to be the case. Many pregnant ewes were in- 

 oculated with the vibrios by various channels. Some of 

 these aborted, but for the most part they did not. In some 

 of the aborts and the uteri of the aborters the vibrio could 

 be identified ; in some it could not. The grounds for assum- 

 ing that the inoculated ewes did not already carry in utero 

 the vibrios are not stated, and apparently no controls were 

 kept. Nothing is submitted to show that these ewes taken 

 from their familiar suroundings would not have aborted in 

 the same ratio if not inoculated. The evidence that a preg- 



1 Abortion in Sheep. Board of Agriculture and Fisheries. London, 1913. 



