Medical Bacteriology. 115 



B. tuberculosis does not grow upon the ordinary artificial media, but may be grown 

 upon blood serum [see p. 89 (1) ] and bouillon, agar and potato to which 5% of glyc- 

 erine has been added. The tubercle bacterium is very sensitive to temperature varia- 

 tions and should therefore be kept at a temperature varying at most only a degree or 

 two from 38 C. It is also extremely sensitive towards desiccation and for this reason the 

 cotton plug should be well paraffined or replaced by a cork through which a small cotton 

 plugged glass tube passes and the incubator kept saturated with moisture. For methods 

 of culture and isolation see Smith: Jour. Exp. Med., 1898, 3; 456. 



