5IO Diseases of the Genital Organs 



could show that B. abortus has caused a given abortion, a 

 typical reaction of an aborting cow to the tuberculin test 

 would show that the abortion was due to the infection of 

 tuberculosis. I have seen a high B. abortus agglutination 

 reaction in a sterile heifer never known to have conceived, 

 in which, upon autopsy, B. abortus was recovered from the 

 udder but not from the genital tract. The sterility was ap- 

 parently due to streptococcic salpingitis. Doubtless her 

 blood would also have reacted strongly to the streptococcus. 

 In the researches in my department, the blood of cows in 

 which harmful genital infections exist reacts to several 

 species of bacteria, such as paracolon and streptococci, but 

 the reactions show merely the presence of such bacteria 

 somewhere in the body, and can not show that they cause 

 sterility or abortion. The agglutination test for the pres- 

 ence of B. abortus is in itself fundamentally defective. I 

 injected living B. abortus cultures in the jugular vein of a 

 two-year-old pregnant heifer. She probably already had B. 

 abortus in her utero-chorionic cavity. The agglutinating 

 power of her blood was followed from 0.02 up to 0.001 and 

 in its descent until minus at 0.02. Then she aborted and 

 was promptly destroyed. Her blood was negative at 0.02, 

 and her uterus was swarming with B. abortus. 



A vital defect of the agglutination test for the presence of 

 B. abortus is the total absence of knowledge of the physi- 

 ologic agglutinating power of bovine blood. Some consider 

 an agglutination at 0.02 as proof of infection ; others place 

 the infection-point at 0.01. As a rule the blood of new-born 

 calves is negative at 0.1 and can be held there experimentally 

 as long as I have cared to do so. If the calf is fed in the or- 

 dinary manner, its blood commonly reacts positively at 0.1 

 or higher within thirty days. I have seen it react at 0.002 

 at thirteen days. The common practice of fixing upon 0.02 

 or 0.01 as denoting infection is absolutely arbitrary and un- 

 supported by any recorded attempt at justification. There 

 is no more reason for believing that agglutination at 0.02 

 or 0.01 denotes infection than for declaring that agglutina- 

 tion at 0.04 or 0.1 indicates infection. 



