CHAPTER II. 



THE VITAL PHENOMENA OF BACTERIA. 



IF we accept the nebular hypothesis of the 

 origin of the solar system, we must believe 

 that the first living things developed under 

 conditions which, in respect to temperature, 

 light and atmospheric oxygen, departed widely 

 from those prevailing at the present time. 

 The atmosphere must have been poorer in 

 oxygen, poorer in light and possessed of a 

 higher temperature. In view of this fact, it is 

 interesting to note that among bacteria, spe- 

 cies are found that are able to live without free 

 oxygen, without light, and at a relatively high 

 temperature and this to an extent known 

 among no other group of living things. 



Anaerobiosis Relations to Energy. 



To the genius of Pasteur we are indebted 

 for the remarkable observation that microbes or 

 micro-organisms can live without free oxygen. 

 In life without air that is to say, without the 

 oxygen of the air in the absence of this " food 



