152 PHYSIOLOGY OF THE BACTERIA. 



and dead nature, if the air has always the same 

 composition, if the waters are always equally fer- 

 tilizing, it is thanks to the infinitely minute agents 

 of fermentation and putrefaction" (Duclaux). 



But the role of bacteria is not limited to this. 

 " They invade also the living organism," says Du- 

 claux, " and bring in their attack this double char- 

 acter of infinite smallness in the apparent means 

 and powerful destructive energy in the results. 

 From this source come diseases of which medicine, 

 not long since, did not know the cause, and which 

 she only commences to refer to their veritable 

 origin. For those who are au courant with the 

 first steps which she has made in this new line of 

 research, with the fecundity of her first glimpses, 

 with the richness of her first results, it is not 

 doubtful that she will soon succeed in demonstrat- 

 ing the parasitic nature of the gravest epidemic 

 maladies " 



