184 



PHYSIOLOGY OF BACTERIA 



Most probably, this would be found in the very young, 

 actively growing cells. 



Quite instructive are three series of experiments on 

 the nitrogen fixation by AzotohacteVj made by Koch and 

 Seydel (1912). They determined the nitrogen fixed and 

 the sugar used by Azotohacter at different times, and 

 computed the mg. N2 fixed per gram of dextrose. Nitro- 

 gen is not a direct measure of growth, but is as good as 

 any of the other methods. 



Table 44. — Nitrogen Fixation and Sugar Consumption by 

 azotobacter 



Experiment III; 7.445 gm. dextrose in 50 c.c. 



Experiment IV; 2.316 gm. dextrose in 50 c.c. 



