CONDITIONS OF GROWTH. 57 



temperature near that of the body for their develop- 

 ment, while many saprophytic bacteria can grow only 

 at much lower temperatures. Bacteria when exposed 

 to lower temperature than suffices for their growth, 

 while having their activities decreased, are not other- 

 wise injured; while exposure to higher temperatures 

 than allows of growth destroys the life of the bacteria. 

 The relations of the temperature to bacterial life and 

 death will be dealt with fully in a later chapter. 



