44 CLINICAL BACTERIOLOGY AND 



Bacillus Tuberculosis. 



Biological Characters. — 1. In broth a light yellow mass 

 forms, increasing slowly, the medium remaining clear. 



2. On glycerine agar a dry, wrinkled, brownish-yellow 

 mass forms. 



A guinea-pig should be inoculated with the virus for 

 diagnostic purposes as described on p. 183. 



Staining. — Ziehl-Neelsen's method, as described on 

 p. 177. 



The bacillus belongs to the acid-fast group — i.e.,B. Leprae, 

 B. Butyricus, B. Smegmatige, bacillus of Johne's disease, 

 bacillus of Timothy-grass, etc. 



Microscopical Appearances. — This bacillus is a small thin 

 rod, slightly bent, in culture. A chain of four or of eight 

 may be noted. 



This bacillus is aerobic and anaerobic. Minimum tem- 

 perature, 27° C.j optimum, 37° C; maximum, 41° C. Growth 

 slow : about six weeks. 



Bacillus Diphtherias. 



Biological Characters. — 1. In glucose peptone broth note 

 formation of acid, but no gas. 



2. On gelatin plates small white columns develop, and 

 growth is very slow, without liquefaction. 



3. In gelatin (stab culture) at 20° C. surface growth takes 

 place, and the stab growth takes the form of a nail. 



4. On agar small transparent elevated columns occur. 

 Growth scanty. 



4. On Loeffler's serum large white colonies grow. 



Staining. — Methylene blue or weak carbol-fuchsin, and 

 Gram's method. 



Microscopical Appearances. — The bacilli are often arranged 

 in clumps. In shape and size they vary considerably. 



This bacillus is aerobic and anaerobic. Growth takes 

 place between minimum temperature, 10° C. ; optimum, 

 35° C. ; and maximum, 48° C. 



