384 GLANDERS ANTHRAX PYOCYANEUS 



in milk. Melvin 1 has found B. abortus in eight out of seventy-seven 

 samples of market milk and in the milk of six dairies out of a total of 

 thirty-one examined. As early as 1894 Theobald Smith 2 called atten- 

 tion to peculiar tubercle-like lesions induced in guinea-pigs following 

 the injection of cow's milk. He recognized that the disease was not 

 tuberculosis; later Schroeder 3 made similar observations. In the 

 same year Smith and Fabyan 4 showed that, the tubercle-like lesions 

 were caused by B. abortus, and in 1913 Fabyan 5 demonstrated con- 

 clusively the extremely important fact that B. abortus is very fre- 

 quently found in the milk of cows that have aborted. He also showed 

 that pasteurization of milk, if carried out in the proper manner, will 

 certainly destroy the bacillus. Whether certain cases of abortion 

 observed in man are due to the organism is not yet proven. 6 



Bacteriological Diagnosis. The bacteriological diagnosis is best 

 made by injecting guinea-pigs with suspected milk or material from 

 a diseased animal and observing the development of the characteristic 

 tubercle-like lesions. If the animal does not die within a reasonable 

 time it should be killed and autopsied. 



Serological Diagnosis. The blood serum of infected cattle usually 

 agglutinates B. abortus in dilutions greater than 1 to 50. The value 

 of the agglutination reaction as a method of diagnosis is as yet debat- 

 able. The extensive statistics of MacFadyen and Stockmann 7 upon 

 this phase of the subject are representative. An agglutination with 

 B. abortus in a dilution of 1 to 50 was obtained with the sera of 526 

 out of a total of 535 apparently healthy cows;* in the remainder (9) 

 agglutination took place in dilutions greater than 1 to 50. Of 127 

 cattle, either infected or suspects, an agglutination was not obtained 

 in a dilution of 1 to 50; in 11 agglutination was positive, 1 to 50; in 



19 a positive reaction was obtained in a dilution of 1 to 100; and in 



20 a reaction in a dilution of 1 to 200. Holth 8 tested the sera of 7 

 normal cattle with negative results. The sera of 38 animals out of a 

 total of 39, which were plainly infected with B. abortus, gave positive 

 agglutination with the specific organism in a dilution of 1 to 100. 



1 Vet. Jour., 1912, Ixviii, 526. 



2 Bureau of Animal Industry, 1894, Bull. 7, 80. 



3 Bur. Animal Industry, Circ. 198, November 2, 1912. 

 4 Centralbl. f. Bakt., Orig., 1912, Ixi, 549. 



6 Jour. Med. Research, 1913, xxviii, 85. 



6 Recently Laisen and Sedgwick (Am. Jour. Dis. of Child., 1913, vi, 326) have exam- 

 ined blood serum from 425 children by the method of complement-fixation; 73 were 

 positive, 325 weie negative. 



7 Jour. Compt. Path, and Therap., 1912, xxv, 22. 



8 Berl. tierarztl. Wchnschr.. 1909, 686. 



