102 



Mr. E. C. Grey. Decomposition of 



during the second 12 hours is subsequently degraded, it does not in the end 

 change the results. 



Table III. — The Eesults of the various Periods of the Fermentation expressed 

 as Percentages of the Amount of Total Products obtained in each Period, 

 ignoring the Temporary Formation of Non-reducing Carbohydrate. 





1. 



2. 



3. 



4. 



Carbon dioxide 



21 -50 



0-50 



3-70 



8-70 



Formic acid 



9-61 



39 -00 



8-80 



14 60 



Alcohol 



31 -50 



Nil. 



11 -30 



9-20 



Acetic acid 



30 -10 



33 -40 



4-90 



Nil. 





6-37 



23 -80 



0-20 



Nil. 



Lactic acid 



0-88 



3-30 



71 -10 



67 -50 



The results have been calculated to the amount of total products obtained 

 in the period rather than upon the weight of sugar fermented during the 

 period owing to the presence of the non-reducing carbohydrate, i.e., carbo- 

 hydrate which does not reduce copper solution until after hydrolysis. As 

 has been pointed out, it is not possible to be sure of the reduction figure. 

 Moreover, the object of the above Table is to bring out the comparison 

 between the degradation processes occurring during each period, and this 

 comparison is only obscured by the calculation of the results to the sugar 

 which has disappeared, since part of the sugar becomes synthesised into the 

 non-reducing carbohydrate which later undergoes degradation. 



General Considerations. 

 Before discussing the broad conclusions which may be drawn from these 

 researches, the writer would put forward certain considerations with regard 

 to the methods which these results, and the results of previous work also, 

 suggest should be adopted in future work on bacterial fermentation. These 

 suggestions are put forward partly because this branch of chemistry is 

 essentially one in which the co-operation of several workers is needed, and 

 also because the results obtained by adopting the method of research 

 described in this communication warrant the conclusion that a more 

 extended application of these methods would help to elucidate the problems 

 of bacterial enzyme action. With comparatively few experiments it has 

 been possible to show that the enzymes of B. coli comvmnis are, partly at 

 least, independent of one another in their action ; that the degradation of 

 glucose is brought about by means of these independent enzyme fermenta- 

 tions acting either simultaneously or consecutively, and that the same set 

 of enzymes produced by the bacterium serve for the degradation of 

 substances allied to glucose, such as mannitol. It has been shown also 



