ORIGIN OF LOWEST ORGANISMS. 27 



nary Bacteria germs,* which we are supposed to be 

 unable to distinguish ? M. Pasteur may, moreover, 

 be reminded that when he resorts to the supposition 

 of Bacteria possessing "germs" . which are indistin- 

 guishable, he is again resorting to hypothesis rather 

 than to fact, in order to prove the truth of the 

 particular doctrine of fermentation which he advo- 

 cates. Bacteria are known to reproduce and multiply 

 only by a process of fission ; each of the parts into 

 which they divide being nothing more than a part of 

 the oria;inal Bacterium, and therefore endowed with 



o 



similar properties of resisting heat, desiccation, and 

 other agencies. Any resort to invisible germs to 

 account for the multiplication of Bacteria, which are 

 known to reproduce freely in other ways, is obviously 

 not permissible, unless such postulation be more or 

 less necessitated by the occurrence of facts otherwise 

 inexplicable. 



* M. Pasteur's use of this term, in which he is followed by 

 others holding similar opinions, is much to be deprecated. 

 Having said that he had found certain corpuscles which resem- 

 bled spores of fungi, or ova of infusoria, he subsequently speaks 

 of them as " germs," and also applies the same name to the repro- 

 ductive particles of Bacteria, which he merely assumes to be 

 present in the atmosphere. Thus, having only proved that 

 corpuscles resembling spores of some fungi, are to be found in 

 the atmosphere, he subsequently speaks of the presence of a 

 multitude of atmospheric germs as an established fact, without 

 at all prominently pointing out that, so far as the most important 

 of these are concerned germs of Bacteria their existence had 

 only been inferred, and not proved. 



