63 



these cultures in the next exercise and compare them with 

 the notes on cultures of B. coli communis in these media. 



Examine and carefully describe the cultures of B. chol- 

 erae suzs, and B. typhosus. Note especially the reaction of 

 the cultures in the fermentation tubes. Examine the 

 bouillon cultures microscopically, (a) in hanging-drop, and 

 (b) in stained (methylene-blue) cover-glass preparations. 

 Describe the appearance of the bacteria. 



Make a series of three gelatin plate cultures from the 

 bouillon culture of each organism. 



EXERCISE XXXII. 



BACILLUS CHOLERAE SUIS AND BACILLUS TYPHOSUS 



( continued J. 



103. General directions. Re-examine all of the cultures 

 of B. cholera suis and B. typhosus. Note especially the condi- 

 tion of the fermentation tubes. Keep the milk and the litmus 

 milk cultures in the incubator for about 5 weeks and note 

 any changes which may take place from week to week. 



Examine and carefully describe the colonies on the gelatin 

 plates. 



Try the indol test ( 98) with the cultures in Dunham's 

 solution. 



Make and stain with alkaline methylene-blue a few (3 or 

 4) cover-glass preparations from the organs (liver, spleen, 

 kidney or blood) of a rabbit which has died from the effect 

 of the inoculation with hog-cholera bacilli. Note the number 

 (few or many) of the bacteria in the preparations and pre- 

 serve one of them to accompany the notes. Make a draw- 

 ing of a few bacilli. 



Examine and complete the notes on the culture of B. coli 

 communis. Compare them with the cultures of hog-cholera 

 "and typhoid bacteria. 



