ISOLATION OF NITRIFYING FERMENTS 213 



A culture medium was then prepared which was free from every 

 trace of organic matter. On being inoculated, nitrification took 

 place in this energetically, and it was found to contain large num- 



& 



b " * 



* . . 



-8, * 



% * 



* 







FIG. 31. Nitrobacteria from cultures in liquid medium stained with carbol Fuchsin. 

 X 2500. (After Gibbs: Soil Science.) 



bers of the oval bacteria, as well as the fungus form previously 

 noticed, but the other forms had all disappeared. The fungus 

 remained constant, and all attempts to cultivate it out were unsuc- 

 cessful. 



