64 A MANUAL OF BACTERIOLOGY 



another. Sometimes a combination of the fractional 

 and dilution methods is used for the same purpose. 

 The methods of cultivating anaerobic microbes 

 are somewhat different from the above ; as the air 

 I must be excluded from the cultivation apparatus. 

 In the cultivation of Bacillus cholerce Asiaticce, Koch 

 made use of plate cultivations on which very thin 

 sheets of glass or mica were placed before the 

 gelatine was perfectly set. By this means the 

 colonies of microbes grow out of contact with the 



o 



air. 



A second method for excluding air (i.e. oxygen) 

 is to allow the microbes to grow under the receiver 

 of an air-pump which has been exhausted of air. 



A third method is to allow the microbes to grow 

 in an atmosphere of carbonic anhydride or hydrogen 

 gas. Another method consists in inoculating a 

 cultivation tube with the anaerobic microbe, and 

 then covering the surface of the medium with a 

 layer of sterilised oil. 



Dr. Eoux has also devised two methods for this 

 object. One of these methods is to fill a sterilised 

 pipette with sterilised nutrient gelatine. Both ends 

 of the pipette are hermetically sealed. To inoculate 

 the gelatine, one end of the pipette is nipped* off, 

 the inoculating material introduced, by a fine glass 

 needle, into the gelatine, and finally the open end 

 of the pipette is again sealed. By this device the 

 microbes grow anaerobically. The second method 

 of Dr. Eoux is to boil a quantity of agar-agar in a 

 test-tube ; and after quickly cooling, the medium is 

 inoculated with the anaerobic microbe. A layer of 



