ACID-FAST BACILLI OTHER THAN BACILLUS TUBERCULOSIS 471 



Pathogenesis. Bacillus phlei is not pathogenic for man, so far as 

 is known, but the introduction of large numbers of the organisms 

 into the peritoneal cavity of guinea-pigs leads to the formation of 

 localized nodules which eventually soften and contain a purulent, 

 somewhat caseous mass. Typical tubercles with giant-cell and epithe- 

 lio id-cell formation are not observed. Moderate doses do not cause 

 death, but very large doses frequently lead to fatal results. The 

 inoculated animals fail to give any reaction whatsoever with tuberculin 

 derived from human or bovine cultures. 



The organisms are of practical importance because they may be 

 confused with the tubercle bacillus. A simple microscopic examina- 

 tion may in rare instances lead to error, but the correct differentiation 

 between these organisms and the tubercle bacillus may be safely 

 arrived at by their injection into guinea-pigs and the subsequent 

 negative reaction with a fairly large dose of tuberculin. 



The Butter Bacillus. This organism was first described by 

 Rabinovitsch, 1 and subsequently her observations were confirmed and 

 extended by Petri. 2 



Morphologically the organisms are very similar to tubercle bacilli, 

 but they are relatively less acid-fast. Differentiation between the 

 butter bacillus and the tubercle bacillus, however, can not be made 

 upon this basis. The organisms grow in culture media very like the 

 grass bacilli. In broth the medium remains clear and the organisms 

 form a thick, wrinkled pellicle on the surface. Very frequently there 

 is a distinct ammoniacal odor to the broth, and it is said that they 

 form small amounts of indol. 



So far as is known the butter bacilli are non-pathogenic for man 

 and the lesions they induce in guinea-pigs are very similar to those 

 produced by the grass bacilli. They are chiefly confusing when they 

 are found in milk and butter because of their resemblance to the bovine 

 tubercle bacillus. A distinction between the butter bacillus and the 

 bovine tubercle bacillus can be definitely made by injection into guinea- 

 pigs. The lesions are not tubercular in nature, and the animals fail 

 to react to tuberculin. 



1 Ztschr. f. Hyg., 1897, xxvi, 90. 2 Hyg. Rund., August 15, 1897. 



