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 suis, 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. cholercB 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 bacteiria. 



