224 



PHYSIOLOGY OF BACTERIA 



ophilus in milk at low temperatures has also been 

 recorded by Kopeloff (1926). Graham-Smith (1920) 

 also reports a slow decrease in the number of viable 

 cells of Micr. pyogenes in broth at 8-10°C. 



Table 59. — Increase and Decrease of Streptococci at Low 



Temperatures 



(Colonies per c.c.) 



Strept. cremoris No. 18 



Strept. cremoris No. 23 



Strept. lactis 



Another fact must be mentioned here which is still more difficult 

 to explain biochemically, namely the adaptation of organisms to 

 certain temperatures. This is shown very plainly in Table 60 

 representing some experiments of Zikes (1919b) with yeast. Of 

 each of the six yeasts tested, one culture was grown at 8°C., and 

 another at 25°C., for several weeks previous to the final test. The 

 temperature of precultivation had a very decided influence upon 



