EXERCISE XXXV 



BACILLUS CHOLERA SUIS AND BACILLUS TYPHOSUS 

 (Continued^ 



122. Work for this Exercise. — Reexamine all of the cul- • 

 tures of B. cholera suis and B. typhosus. Note especially the 

 condition of the fermentation tubes. Keep the milk and the 

 litmus milk cultures in the incubator for about 6 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 (ii6) with the culture in sugar- free 

 bouillon. 



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 preserve one of 

 them to accompany the notes. Make a drawing 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. 



123. Making Cover-glass Preparations from Tissues With 



a pair of fine forceps take up a bit of tissue from the freshly cut 

 liver, spleen, or kidney, and rub it gently over the surface of a 

 clean cover-glass. Care must be taken that the film of tissue 

 left on the cover-glass is thin. Allow this to dry in the air, 

 after which pass the cover-glass, film up, three times through 

 the flame to fix the tissue to the glass. They can be stained 

 the same as the cover-glass preparations from the cultures. 

 These are often spoken of as smear preparations. 



In making these preparations from blood, hold a cover-glass 



