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 glye- 
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° ©. Itis 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. 
