118 PHYSIOLOGY OF THE BACTERIA. 



he says, " that the complete development of Bacil- 

 lus, and above all reproduction by means of spores, 

 is only made under the influence of free access 

 of air." 



We might explain the contradictory facts of 

 Pasteur by admitting, with Cohn, that the appear- 

 ance of different roles played by the aerobies 

 (Bacterium) and the anaerobies (Bacillus) is sim- 

 ply due to a veritable struggle for existence which 

 takes place between the microbacteria and the 

 desmobacteria. 



Action op Various Agents upon the Bacteria. 



In this paragraph I shall pass in review the 

 action of temperature, of movement, and of va- 

 rious antiseptics. 



Temperature. — It is very important to study 

 the manner in which bacteria comport themselves 

 under extreme variations of temperature. It is, 

 indeed, upon the results furnished by these re- 

 searches that a great part of the arguments op- 

 posed to the panspermatists by the heterogenists 

 are based. 



We shall consider the influence upon bacteria 

 of moderate temperatures and of extremes above 

 and below zero. 



Moderate temperatures — that is to say those 

 which are comprised between 25 and 40° (77 to 

 104° Fah.) — are generally favorable. The most 

 favorable has been found to be 35° (95° Fah.) 

 (Onimus). 



