BOVINE TUBERCULOSIS. 265 



Both bovine and human tuberculosis are caused by a bacterium 

 that has great similarity in the two animals. But there are slight 

 differences between them, both in microscopic appearance and in 

 methods of growth, sufficient to make it necessary to recognize them 

 as somewhat different types. When inoculated into animals, the 

 organism from the bovine source proves to be more virulent than 

 the one from the human source. The human bacillus, when 

 inoculated into cattle, generally produces only a slight trouble, 

 while the bovine bacillus is apt to bring about a progressive case of 

 the disease of very serious character. What effect the bovine 

 bacillus has when inoculated into man cannot yet be told from 

 direct experiment, but there appear to be a number of tolerably 

 sure cases of accidental inoculation of human beings with the bovine 

 bacillus that have been followed by a development of the disease. 

 The general conclusion is that, although the two are slightly different, 

 each may produce the disease in the other animal, and that the 

 disease is, therefore, transmissible from animals to man. While the 

 conclusion is still doubted by Prof. Koch, it is accepted by most 

 other bacteriologists. Whether the bovine bacillus is more virulent 

 for man than is the human bacillus, as it is for other animals, is by no 

 means settled. Furthermore, it is pretty generally agreed that 

 human tuberculosis comes more often from human sources than 

 from cattle. 



BOVINE TUBERCULOSIS. 



In recent years, owing largely to the feeding of swine with 

 creamery refuse, the disease is coming to be somewhat common 

 among swine. But it is among cattle that the trouble is most 

 widely distributed and of the most serious import. In cattle it 

 at lacks chiefly the glands of the neck, the glands of the intestinal 

 tract, and the lungs. It may be located in the udder; and in these 

 cases the milk of the animal becomes a source of danger. For- 

 tunately, the percentage of cases of udder disease is comparatively 

 small. In cattle it rarely attacks the bones, joints, or muscles. 

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