Mr. E. C. Grey. Decomposition of 



products resulting from the fermentation and also for the enumeration of 

 the living bacteria. The operation was repeated at 24, 48 and 72 hours 

 from the commencement of the experiment. The number of bacteria living 

 was determined in each case by plating out on nutrient agar. 



The experiment was thus divided up into four periods. The nature of 

 the change during any period was ascertained by a comparison between the 

 composition of the fermentation solution at the beginning and end of the 

 period. The changes in the number of the bacteria and the extent to which 

 the sugar was fermented during each period may be seen from the following 

 figures. 



Period. 



Dura- 

 tion. 



Number of bacilli 

 per c.c. of the 

 solution at the 

 beginning of each 

 period in milliards. 



Amount of 

 sugar at 

 the staa-t 

 of the 

 period. 



Amount of 

 sugar at 

 the end of 

 the period. 



Amount of 

 sugar 

 changed 

 during the 

 period. 



Volume of 

 the solution 



during 

 fermentation. 





hrs. 





grm. 



grm. 



grm. 



c.c. 



1 



12 



217,000 



45 -84 



35 -06 



10 -78 



5100 



2 



12 



4-5 



30-95 



20 -41 



10 -54 



4400 



3 



24 



1,400,000 



16-79 



10 -09 



6-70 



3620 



4 



24 



450,000 



6-84 



3 -8 



3-54 



2214 





72 













The following facts may be noted. During the first period of 12 hours 

 there is an enormous falling off in the niimber of living bacteria, and during 

 the second period of 12 hours there is a still greater increase in the number 

 which are living. Subsequently there is a diminution also but proportionally 

 small as compared to the diminution during the first period. In spite of the 

 fact that the first period is characterised by rapid diminution and the second 

 period by rapid multiplication of the bacteria, nevertheless the amount of 

 sugar transformed into products which do not reduce copper solution is 

 approximately the same in both cases. 



The sample which was removed for analysis at the end of the first 

 12 hours gave the following results. In the result must also be included the 

 caroon dioxide evolved during this period. 



