CHAPTER XIX 

 THE GROUP OF ACID-RESISTING BACILLI 

 Members — 



Bacillus tuberculosis. 

 B. leprae. 

 B. smegmae. 



Moeller's grass bacilli, including a number of bacilli found 

 on grass, dung, in butter, milk, etc. 



For obvious reasons, B. tuberculosis will not be studied 

 culturally. For comparison, the culture characteristics of 

 Moeller's grass bacillus are instructive. 



Inoculate an agar-slant from a stock-culture of 

 Moeller's grass bacillus. 



1. Routine study. 



2. Special study A . — Method of staining acid-resisting 

 bacilli. 



a) Pick out purulent matter from the sputum oi a 

 tuberculous patient and spread carefully on a cover- 

 glass. 



b) Dry and fix as usual. 



c) Heat for one minute on a water-bath at ioo°, or 

 over a small flame with carbol-fuchsin. 



d) Decolorize with acid alcohol (2 per cent. HCl in 

 80 per cent, alcohol) until the film in its thin parts has 

 lost almost all its color. 



e) Counterstain with methylene-blue for 10 seconds 

 (cold). 



/) Examine and mount in balsam. 



Note. — Make a second preparation, substituting anilin- 

 gentian-violet for carbol-fuchsin, and Bismarck brown for methy- 

 lene-blue. 



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