BACTERIUM TUBERCULOSIS QI 



EXERCISE XXXVI 



BACTERIUM TUBERCULOSIS 



132. The tubercle bacterium does not grow readily on the 

 ordinary media. For its cultivation blood serum, glycerin agar, 

 or bouillon containing from 5 to 7% glycerin is ordinarily 

 used. Formerly it was with much difficulty that it was made 

 to grow from lesions in tuberculous animals ; but when a culture 

 was once started it could, on the media mentioned above, and 

 sometimes on agar, be cultivated in subcultures with compara- 

 tive ease. More recently Dr. Theobald Smith has described 

 a method which renders its cultivation from tuberculous lesions 

 much easier (for details, see Appendix IV). It grows very 

 slowly and it is necessary that the temperature should be kept, 

 without variation, at about 37 C. The avian variety grows 

 much more readily on glycerin agar, egg medium, serum, and 

 in glycerin bouillon. On account of these difficulties it is 

 not practicable, in a general course, to cultivate this organism, 

 but cultures on solid and liquid media will be furnished by 

 the instructor for examination. It is important, however, to 

 be able to recognize this organism in tissues and sputum, and 

 consequently the following additional exercise in staining and 

 studying it is given. 



REFERENCES. Chapters on this organism in text-books. Smith, 

 Jour, of Exp. Med., 1898, p. 451. Moore, Med. News, May 14, 

 1892 (methods of staining). Nuttall, Johns Hop. Hosp. Bulletin, 

 1891, Vol. II, p. 67. Dorset, Report Am. Public Health Asso., 

 Vol. XXIV, p. 157. 



133. Work for this exercise. Examine and carefully 

 describe the appearance of the cultures of the tubercle 

 bacterium (human or bovine variety) on glycerin agar and in 

 glycerin bouillon furnished. 



