510 



BACTERIOLOGY. 



By the employment of this apparatus one can make 

 these analyses at any place, and can, without fear of 

 contamination, carry the tubes to the laboratory, where 

 the cultivation part of the work may be done. 



Fig. 105. 



Bent funnel for use with aerobioscope. 



Aside from this advantage, the filter being soluble 

 only the insoluble bacteria are left imbedded in the 

 gelatin. 



For general use this method is to be preferred to the 

 others that have been mentioned. 



Bacteriological Study of the Soil. — Bacterio- 

 logical study of the soil may be made by either breaking 

 up small particles of earth in liquefied media and mak- 

 ing plates directly from this, or by what is perhaps a 

 better method, as it gets rid of insoluble particles which 

 may give rise to errors : breaking up the soil in steril- 

 ized water and then making plates immediately from 

 the water. 



