Jan. 28, 1918 



Nitrogen-A ssimilating Bacteria 



201 



with strain A and three with strain B, and the remaining three were left 

 uninoculated to serve as controls. The flasks were incubated at 28° C. 

 for 21 days. The total weight was maintained throughout the experi- 

 ment by the addition of sterile distilled water from time to time. At the 

 end of three weeks the contents of each set of triplicate flasks were poured 

 together and 50-c. c. samples drawn for analysis. Nitrate ammonia and 

 total nitrogen were determined as given under "Methods." The results 

 are shown in Tables XIV, XV, and XVI. 



Table ^1\ .^Influence of Azotobacter on nitrates in solution, giving the quantity of 



nitrate lost 



1 strong NO2 r,eaction. 



6 Medium NO2 reaction. 



cSlightNO: reaction. 



Table XV. — Influence of Azotobacter on nitrates in solution, giving the quantity of 



ammonia produced 



