TIMOTHY AND OTHER GRASS BACILLI. 319 



TIMOTHY AND OTHER GRASS BACILLI. 



On various grasses, in cow's manure, in butter, and in 

 milk, there have been discovered a number of varieties 

 of bacteria which have more or less of the characteristics 

 of the tubercle bacillus. Some of them are as difficult to 

 stain and as resistant to decolorizing action of mineral 

 acids and alcohol as the tubercle bacillus found in man. 

 Many of them are of the same general size and shape as 

 the tubercle bacillus,, and, strangely enough, produce 

 in animals small diseased areas, which not only macro- 

 scopically but also microscopically resemble miliary 

 tubercles due to the tubercle bacillus. They, however, 

 are entirely different in their culture characteristics, 

 producing in twenty-four to forty-eight hours on ordi- 

 nary culture media moist, round colonies of an eighth 

 to a quarter of an inch in diameter, and of a more or 

 less intense pink color. In animals they produce only 

 localized lesions, causing death only when injected in 

 large numbers. The injected animals are unaffected 

 by tuberculin injections. The chief interest which 

 these bacilli have for us is the possibility of confusing 

 them with the tubercle bacilli. This danger is always 

 present in milk, for the grass bacilli find so many 

 means of gaining entrance to it. In the examination 

 of dust, healthy throat and nose secretions, etc., the 

 simple microscopical examination might lead to error. 



They can be separated from tubercle bacilli by in- 

 oculating animals, and then if they show any infection, 

 injecting tuberculin, when if infected with tuberculosis 

 they will die, but if by grass bacilli they will show 

 no reaction. Cultures from the lesions will also show 

 on ordinary media pink colonies if grass bacilli are 

 present, and no growth if only tubercle bacilli. 



