76 LABORATORY BACTERIOLOGY 



121. Work for this Exercise. — Examine the plate cultures 

 made from the intestine for the colon bacillus. 



Determine the approximate number of colonies on each 

 plate and note especially the number of colonies of B. colt 

 communis and describe their appearance. 



Inoculate a tube of agar, one of milk, and a fermentation 

 tube of glucose bouillon from one of the colonies. Study 

 these cultures in the next, exercise and compare them with the 

 notes on cultures of B. colt communis in these media. 



Examine and carefully describe the cultures of B. chokrcB 

 suis and B. typhosus. Note especially the reaction of the cul- 

 tures in the fermentation tubes. Examine the bouillon cul- 

 tures microscopically {a) in hanging-drop and {l>) in stained 

 (methylene-blue) cover-glass preparations. Describe the ap- 

 pearance of the bacteria. 



Make a series of 3. gelatin plate cultures from the bouillon 

 culture of each organism. 



