332 THE AMERICAN MONTHLY [Nov 



Preparation of Glucose Agar. — Prepare 100 c.c. of 

 agar. Reserve one half of it for glycerine agar and to the 

 other half add 1 per cent glucose. Dissolve the powdered 

 glucose in about 5 c.c. of boiled,hot water before adding it 

 to the liquid agar. After thoroughly mixing distribute 

 it in small sterile test tubes. Sterilize, label, and store 

 the same as ordinary agar. 



Preparation of Glycerine Agar. — Take the balance 

 of the agar prepared above and add 5 per cent of pure 

 glycerine. Thoroughly mix it with the liquid agar, after 

 which distribute it in tubes. Sterilize, label, and store 

 as ordinary agar. 



Preparation of Glucose Bouillon. — This is used in 

 the fermentation tube. Take 100 c.c. of peptonized bouil- 

 lon and add 1 gram of pure grape sugar (glucose). Af- 

 ter it is dissolved and thoroughly disseminated through 

 the bouillon by stirring or pouring, distribute the bouil- 

 lon in the fermentation tubes, filling completely the closed 

 branch and the open bulb about half full. Sterilize it by 

 discontinuous steaming for twenty minutes each day for 

 three consecutive days. 



Preparation of Lactose Bouillon.-— This is prepared 

 by adding 1 per cent lactose to the peptonized bouillon. 

 It is necessary, however, that the bouillon used does not 

 contain muscle sugar. Bouillon free from muscle sugar 

 can usually be obtained by macerating the meat for from 

 12 to 18 hours at a low temperature. After adding the 

 lactose and thoroughly mixing it in the bouillon, sterilize 

 label, and store. 



Saccharose Bouillon. — This is peptouized bouillon to 

 which 1 per cent sacchrose has been added. It is pre- 

 pared from bouillon free from muscle sugar, in the same 

 manner as lactose bouillon. 



