100 



Mr. E. C. Grey. Decomposition of 



magnitude to the gain of the previous experiment and that the two results 

 taken together would balance. This seems to indicate that the error lies in 

 the determination of the residual glucose by the reduction of copper. 



The most striking fact observed in the result of the third period of 

 fermentation is that it is mainly a lactic acid production ; 60 per cent, of 

 the carbohydrate fermented has been transformed into lactic acid. 



The synthetic period during which there is practically no lactic acid formed 

 is immediately followed by a degradation process both of the sugar in the 

 solution and also the carbohydrate previously elaborated. This degradation 

 period is characterised by the formation of a very high yield of lactic acid, 

 which in part, at least, comes from the carbohydrate previously synthesised. 

 The production of alcohol, which had ceased during the period of rapid 

 growth and multiplication of the bacteria, viz., the period of synthesis, 

 commences agam in the ensuing period of degradation. The second period of 

 alcohol production, like the first, is a period of death for the bacteria. 



Products of the Fermentation of Glucose formed during the Tliird 24 Hours of 



the FermcntoMon. 



grm. grm. 



Weight of glucose fermented 3'41 



Weight of non-reducing carbohydrate fermented 0'67 



4-08 



Products found — 



Carbon dioxide 0'37 



Formic acid 0'62 



Acetic acid Nil. 



Succinic acid Nil. 



Lactic acid 2'86 



Ethyl alcohol 0-39 



4-24 



Hydrogen not estimated. 



It will be seen that the fermentation that has taken place during this 

 interval is in the main the same as during the preceding interval of 24 hours. 

 The whole period is chiefly characterised by the production of lactic acid. 



The excess of formic acid over alcohol is not in keeping with the results of 

 pre^'ious analyses, for it has always been formd that the ratio of alcohol and 

 acetic acid to formic acid is a constant,* but there are reasons to doubt the 

 correctness of this formic acid figure obtained here, since it was found that 

 the solution of sodium formate gave a precipitate of iodoform in the cold on 



* Grey, 1914. 



