The Enzymes 0/ B. coli communis. 



137 



Table I. — Fermentation of Glucose by B. coli communis grown anaerobically. 

 The fermentations carried out in Nitrogen (N), Air (A), and Oxygen (0), 

 respectively. 



Products. 



Products as percentages of glucose employed. 











N. 



A. 



0. 





-61 



0-50 



0-40 





2" -33 



24-17 



20 -00 





16 -68 



12 -33 



0-08 





8-67 



9-50 



18 -15 





9-83 



10-33 



12-33 





Nil 



12 -00 



8-83 





7-33 



8-66 



9-00 



< 



Total 



70 -45 



77 -49 



68 -19 



It will be seen that there is a gradual diminution of CO2 production with 

 increasing oxygenation, and a still greater diminution of formic acid. The 

 effect of admitting oxygen during the fermentation, however, will be discussed 

 more fully in Section B of this communication. 



Most striking of all is the absence of lactic acid from the completely 

 anaerobic fermentation, and the reappearance of this acid with aeration. It 

 is possible that the missing 30 per cent, of glucose has in part been converted 

 into some mother substance of lactic acid. In Part III of this series an 

 experiment is described in which samples of the fermentation fluid were 

 removed for analysis every twelve hours. At the end of the first period of 

 twelve hours which had been one of rapid death of the bacteria introduced, 

 no lactic acid was found, in the second twelve hours although the glucose 

 disappeared as -evidenced by Fehling's Solution, the products recovered only 

 represented a small fraction of the glucose consumed, but in the third period, 

 from twenty-four to forty-eight hours, all the missing glucose reappeared as 

 lactic acid. It would thus seem that the transformation of glucose into some 

 non-reducing carbohydrate is a preliminary reaction to lactic acid formation, 

 and this probably accounts for what has happened in Experiment I. 



The results of Table I are represented pictorially in fig. lA. 



Experiment II. — The bacteria were grown anaerobically as before. In B 

 the fermentation was completely anaerobic while in C air was admitted. 



