TUBERCLE BACILLUS 2IQ 



pathogenic for human beings. Men have been infected on the 

 hands, while performing autopsies on tuberculous cattle, and 

 their skin lesions showed, histologically, unmistakable tubercles. 

 Cattle have been infected by bacilli of the human type. The 

 bovine type of bacillus differs from the human in the following 

 ways: 



1. It is much more pathogenic for guinea pigs and rabbits. 



2. It produces more extensive lesions in cattle. 



3. It is shorter than the human. 



4. It produces more alkali in acid media. 



5. It is more readily isolated from original lesions and does 

 not demand animal juices in culture media so emphatically. 



The subject of the infectiousness of bovine tuberculosis for man 

 has lately been exhaustively studied by Park and Krumwiede. 

 Their conclusions are that bovine tuberculosis is practically a 

 negligible factor in adults. It very rarely causes pulmonary 

 tuberculosis or phthisis, which disease causes the vast majority 

 of deaths from the spread of virus from man to man. In children, 

 however, the bovine type of tubercle bacillus causes a marked 

 percentage of cases of cervical adenitis leading to operation, tern 

 porary disablement, discomfort and disfigurement. It causes a 

 large percentage of the rarer types to alimentary tuberculosis 

 requiring operative interference or causing the death of the child 

 directly or as a contributing cause in other diseases. In young 

 children it becomes a menace to life and causes from 6 L to 10 

 percent of the total fatalities from this disease. 



It is not always easy to differentiate the tubercle bacillus from 

 other pathogenic and comparatively harmless acid-fast bacilli. 

 Among these are the B. lepra, the B. smegmatis, and a number 

 of organisms found in butter, milk, hay, grass, and in the blind 

 worm. Culturally, the difference is great. The surest way to 

 differentiate the tubercle bacillus from other acid-fast organisms 

 is by animal inoculations. 



For the discovery of tubercle bacilli in materials apt to contain 



