364 



PHYSIOLOGY OF BACTERIA 



of the data are shown in Table 115. Usually, 

 the temperature coefficients were but slightly above 

 normal, but occasionally, they went much higher. 



Chick made the very remarkable observation that the 

 temperature coefficient increased with an increase in 

 the number of cells used for the test. 



Young cultures show a higher temperature coefficient 

 than old ones. This leads to the consequence that 

 at very low temperatures, the death rates of young and 

 old cells must be nearly alike while ordinarily young cells 

 are much more sensitive (see p. 289). 



These still unexplained complications of the tempera- 

 ture effect upon chemical disinfection should caution 

 us against hasty conclusions. 



Several very extensive experiments on the influence of temperature 

 have been published by Gegenbauer and Reichel (1913) concerning 

 the action of hydrochloric acid on spores of B. anthracis, including 

 the change of acid concentration, and the addition of NaCl. The 

 temperature coefficient is found to be independent of the tempera- 

 ture, averaging 4.6, but it decreases as the concentration of the acid 

 increases. 



