502 Diseases of the Genital Organs 



"A microorganism or minute germ (the abortion bacillus 

 of Bang) is known to be the sole cause of contagious abor- 

 tion." 



Such positive assertions that the specific character of 

 cattle abortion has been absolutely proven experimentally 

 and that the Bacterium abortus is the cause, have served to 

 prevent a critical examination of the evidence which has 

 been alleged to prove the specific abortifacient action of the 

 B. abortus. Most writers upon abortion in cattle refer to 

 the experimental production of abortion in pregnant cattle 

 as the corner stone for the positive statements that the B. 

 abortus is the specific agent in abortion. Little has been 

 written concerning the actual recorded evidence. 



In the succeeding table the available recorded data of the 

 experimental efforts at producing abortion with the B. 

 abortus have been assembled, with direct and indirect con- 

 trols. Numerous objections may be urged against their 

 fairness. Tabulation demands brevity and inevitably leaves 

 opportunity for misconception. 



(1) The seven animals consisted of: 



a. Two pregnant cows inoculated in vagina with pure cul- 



tures and killed, one nineteen days, the other twenty- 

 nine days after inoculation. 



b. Two pregnant cows inoculated per vaginam with after- 



birth from an aborter, the one killed thirty-three, the 

 other thirty-five days after exposure. 



c. Two pregnant cows, four and seven years old, a second 



inoculation being made thirty-nine days later, and a 

 third dose twelve days after the second. Seventy-one 

 days after the first inoculation, the seven-year-old cow 

 aborted a five-months fetus. B. abortus and a micro- 

 coccus were found in the placenta. 



d. A six-year-old cow was inoculated per vaginam with pure 



cultures. She calved eighty days later. 11. abortus 

 bacilli were found in uterine contents of the row. 



(2) Out of the twenty-eight experiments recorded by McFadyean 



and Stockman, Experiments Nos. 7, 14, 15, 18, 22, 24 and 25 

 (7) were followed by abortion. In Experiment 13 the fetus 

 underwent desiccation following death but was not expelled. 

 Other animals were killed prior to the termination of preg- 

 nancy, and some might have aborted had they not been killed. 



