5oo Diseases of the Genital Organs 



So much emphasis has been placed upon the power of the 

 B. abortus of Bang to cause abortion during the pregnancy 

 existing at the time of inoculation, that a brief review of the 

 recorded evidence is permissible. 



The Experimental Evidence of the Power of B. Abortus 

 to Cause Abortion 



The dictum of Bang', "Through these two experiments 

 we have submitted the complete proof that the bacilli dis- 

 covered by us are the cause of epizootic abortion," has 

 exerted, and still exerts a profound influence upon the cur- 

 rents of thought regarding abortion in animals. Two basic 

 ideas are included in the quotation from Bang. First, abor- 

 tion is a specific, contagious disease, like tuberculosis or 

 smallpox, caused always by one and the same organism and 

 by one microparasite only. Second, the bacillus described 

 by Bang is the cause and the only cause as proven by his ex- 

 periments. 



For many years the dictum of Bang was generally ac- 

 cepted without reservation. Cattle abortion was regarded 

 as a specific disease apart from all other diseases of cattle, 

 and the B. abortus was considered the specific agent. It is 

 confidently stated that Bang and Stribolt "produced abor- 

 tion in cows with it (B. abortus)"; "The fact seems to be 

 clearly established that the specific cause of infectious abor- 

 tion in cattle is the organism isolated by Bang and Stribolt" ; 

 "That the Bacillus abortus of Bang is capable of producing 

 abortion experimentally in cattle by feeding and by intra- 

 venous injections has been satisfactorily proven by Bang, 

 McFadyean and Stockman, Macneal and Kerr, Good, and 

 others" ; "Abortion disease is a specific infectious disease 

 which is caused by a small germ known as the Bacillus abor- 

 tus of Bang" ; "The cause of abortion is a short, oval-shaped 

 germ {Bael. abortus)"] "The inoculation of pregnant cattle 



. . . produces abortion after a variable length of time"; 



a "Durch diese beiden Versuche haben wir somit den vollen Beweis 

 dafiir Kefiihrt, dass die von uns gefundetun Bacillen die Ursache des 

 seuchenhaften Verwerfens Bind." 



