122 



PHYSIOLOGY OF BACTERIA 



produce measurable amounts of acid at +10°C., but 

 not at 0°C. The temperature coefficient of fermentation 

 at this point equals the rate at 10°C. divided by zero, 

 which is infinite. The same organism will produce 

 acid at 45°C., but no more at 55°C. The temperature 

 coefficient at this point is zero divided by the rate 

 at 45°C. which is zero. Thus, in the very narrow range 

 between and 55°C., the temperature coefficient of 

 fermentation varies from infinite to zero. It is unavoid- 

 able that in this range, there will be a point where it 

 is between 2 and 3 as in normal chemical reactions, but 

 this enormous range is anything but a resemblance to 

 that found in chemical processes. 



That the temperature coefficient of fermentation 

 really increases with decreasing temperature, is shown 

 by Table 20 and Fig. 15 representing the data obtained 

 by Slator (1906) with different yeasts. The curve for 



Qio shows that extrapolation to lower temperatures 

 must lead to infinity while extrapolation to higher 

 temperatures must lead to zero. A similar situation 



