610 BACTERIOLOGY. 



the soil in sterilized water and then making plates 

 immediately from the water. 



It must be borne in mind that many of the ground- 

 organisms bekmg to the anaerobic group, so that in 

 tliese studies this point should be remembered and the 

 methods for the cultivation of such organisms practised 

 in connection with the ordinary methods. It must also 

 be remembered that the nitrifying organisms, every- 

 where present in the ground, cannot be isolated by the 

 ordinary methods, and will not appear in plates made 

 after either of the above plans. The special devices 

 for their cultivation are described in the chapter on 

 soil-organisms. 



