230 



Cultivation of Micro-organisms 



Sugar bouillon is bouillon containing in solution known 

 percentages of such sugars as glucose, lactose, saccharose, etc. 

 As Smith* has pointed out, if the quantity of sugar in the 

 bouillon is to be accurately known, it is necessary to first 

 destroy the muscle sugars in the meat-infusion by adding a 



Fig. 45. Funnel for filling tubes with culture media (Warren) : a, 

 Funnel containing the culture media in liquid condition ; b, pinch-cock 

 by which the flow of fluid into the test-tube is regulated ; c, rubbei 

 tubing. 



culture of the colon bacillus to the meat-infusion and per- 

 mitting fermentation to continue overnight before finishing 

 the bouillon and adding the known quantity of whatever, 

 sugar is desired. About i per cent, of dextrose, lactose, 

 saccharose or galactose is all that is required. More may be 

 injurious. If the bouillon be made from meat extract, fer- 

 mentation may not be necessary. 



The sugar bouillons should not be sterilized in the auto- 

 clave, as the high temperatures chemically alter the sugars. 

 * "Jour, of Exp. Med.," n, No. 5, p. 546. 



