12 THE BACTERIA. 



new transformations, metamorphoses produced, ac- 

 cording to some savants, favored, according to 

 others, but, without contradiction, accompanied 

 by the development of bacteria; 1 and, without 

 wishing to attribute to these organisms a finality 

 which is repugnant to our monistic conception of 

 the universe, it may be said that it is thanks to 

 them that the continuation of life is possible on 

 the surface of the globe. 



But, if these studies are full of interest, their 

 field is so vast that we cannot flatter ourselves 

 that we have passed over the whole of it with 

 equal care. The little time that has been ac- 

 corded us for the composition of this thesis will 

 be our excuse for the inevitable imperfections 

 which will doubtless be found in our work. 



1 The bacteria : such is the subject which has been imposed upon us ; 

 but it is certainly useless to give the reasons which have caused us to 

 study not only the bacteria properly so called, taking the word in its 

 most restricted sense, but all the organisms which are comprised under 

 the names of bacteria, vibrios, schizomyce'tes, schizophytes, etc. 



