438 BACTERIOLOGICAL ANALYSES 



of Parietti's solution respectively. Mark plainly on the outside 

 of each tube the quantity of Parietti's solution it contains. 



2. To each tube add a different amount of the original water, 

 or of the suspension, and incubate at 37 C. 



3. Examine the culture tubes after twenty-four and forty- 

 eight hours' incubation, and plate in nutrient carbolised or potato 

 gelatine from such as have grown. 



4. Pick off suspicious colonies, if any such appear on the plates, 

 subcultivate them upon the various media, and identify them. 



(C) Eisner's Method: This method simply consists in sub- 

 stituting Eisner's potato gelatine (vide page 204) for ordinary 

 nutrient gelatine in any of the previously mentioned methods. 



(D) Cambier's Candle Method: 



Treat a large volume of the water sample by the concentration 

 method (vide page 434). 



1. Remove the rubber stopper from the mouth of the filter 

 candle, introduce 10 c.c. sterile bouillon into its interior, and 

 emulsify the bacterial sediment; replug the mouth of the candle 

 with a wad of sterile cotton-wool. 



2. Remove the filter candle from the filter flask and insert 

 it into the mouth of a flask or a glass cylinder containing sterile 

 bouillon sufficient to reach nearly up to the rubber washer on 

 the candle. 



3. Incubate for twenty-four to thirty-six hours at 37 C. 



4. From the now turbid bouillon in the glass cylinder pour 

 gelatine plates and incubate at 20 C. 



5. Subcultivate and identify any suspicious colonies that 

 appear. 



(The method depends upon the assumption that members of 

 the typhoid and coli groups find their way through the porcelain 

 filter from the interior to the surrounding bouillon at a quicker 

 rate than the associated bacteria.) 



B. Enteritidis Sporogenes. 



1. Transfer 5 c.c. of the emulsion from the filter 

 candle to a sterile test-tube and plug carefully. 



2. Place the test-tube in the interior of the benzole 

 bath employed in separating out spore-bearing organ- 

 isms (vide page 257), and expose to a temperature of 

 80 C. for twenty minutes. 



3. Number ten tubes of litmus milk consecutively 

 from i to 10. 



4. Remove the test-tube from the benzole bath and 

 shake well to distribute the spores evenly through 

 the fluid. 



