130 



PHYSIOLOGY OF BACTERIA 



The decrease of optimal enzyme action with time is 

 very apparent also in the action of pressed yeast juice 

 upon sugar. The following table shows two experiments 



Table 24. — Influence op Temperature upon Fermentation by 



Pressed Juice of Yeast 



(Total CO2 in grams) 



by Buchner, Buchner and Hahn (1903) in which the 

 change of the optimum from 30°C. during the first day 

 to 12-14°C. after six days is very distinct. 



INFLUENCE OF TEMPERATURE UPON FERMENTATION BY 

 LIVING CELLS 



The result of Table 24 that the optimum temperature 

 of fermentation by pressed juice of yeast approaches 

 12°C. seems to be contradictory to the old established 

 fact that living yeast ferments best near 30°C. The 

 necessary conclusion must be drawn from this dis- 



