EXPERIMENT STATION BULLETINS. 629 



the presence of the organism in the front quarter of an infected animal 

 after death. 



Post-mortem examinations of cows reveal nothing to explain the 

 persistent occurrence of the organism in the milk, except a few small 

 areas of slight induration in the udder. The authors found Bad. abortus 

 in 8 samples of market milk among 77 samples tested (over 11 per cent) 

 and in the milk distributed by 6 of 31 dairies (over 19 per cent). Data 

 available at the Experiment Station of the Bureau show that the 

 bacterium of contagious abortion may be eliminated continuously for 

 years with the milk of infected cows that no longer abort. 



Mohler and Traum examined sera from -42 human beings. They ob- 

 tained no positive results either by complement-fixation or agglutination 

 tests. They also obtained tonsils from milk-consuming children at the 

 various hospitals and inoculated guinea-pigs. Out of 56 tonsils and 

 adenoids injected into guinea-pigs, tonsil No. 3 produced nodular areas 

 in the liver, but cultures from this organ remained sterile. Tonsils from 

 case No. 8 injected into 2 guinea-pigs produced in one of them after 

 three months distinct lesions in the liver, spleen, and testicles, and 

 Bad. abortus was obtained from the lesions. 



Using 12 cows from a pure-bred Guernsey herd, two of which had 

 aborted — the rest being chosen indiscriminately, Fabyan was unable to 

 demonstrate the presence of Bad. ahortus in the milk of any animals 

 by cultural methods, but found the milk from the two cows that had 

 aborted to have a much higher initial bacterial count. He also made 

 guinea-pig inoculations using cream and a mixture of cream and sedi- 

 ment. He sums up his results as follows : "These tests show that Bad. 

 abortus may be demonstrated by inoculation into guinea-pigs when 

 cultural methods fail. They also show that B. abortus was present in 

 a herd of cows kept under special precautions; that it was found in 

 the milk of a cow which had aborted at the eighth, but not in one which 

 had aborted in the third month, and that it was present in the milk of 

 a cow which had calved eleven months previous and which had probably 

 given infected milk continuously for nearly a year. It is furthermore 

 evident that milk furnishes a medium in which B. abortus may multiply 

 over long periods of time and remain as a constant source of infection 

 for other cows." 



Zwick and Krage demonstrated culturally the presence of the abortion 

 bacillus in the milk of a cow that had aborted 14 days previously; then 

 in an animal that had aborted 6 months previously and then in an animal 

 13 months after abortion. No abnormalties were discoverable by clinical 

 examination, either in the udder or in the associated glands. The au- 

 thors therefore conclude that either the bacillus is able to pass through 

 the udder without producing lesions at all, or that the lesions are so 

 slight as to be unrecognizable clinically. In order to determine whether 

 the bacillus is responsible for lesions in the udder or changes in the milk 

 and for how long injected bacilli may be excreted with milk, experiments 

 were made in which bacilli were injected into the right halves of the 

 udders of two goats. Examination of the milk showed that the abortion 

 bacilli were excreted therein for a period of 3 to 5 months after the in- 

 jection and that for about 8 weeks the number excreted hardly varied. 

 Bacilli were never obtained from milk withdrawn from the left halves 



