CLASSIFICATION OF THE BACTERIA. 49 



or animal nature of several of the ferments which 

 he has studied," and of which some belong to the 

 bacteria. 



We shall first indicate rapidly the characters 

 which permit us, at first, to recognize certain spe- 

 cies of bacteria as organized beings, to determine 

 if they are animal or vegetable, and finally to 

 classify them either among the algae or among the 

 fungi. 



Distinction of Bacteria from Inorganic Sub- 

 stances. — The question as to whether bacteria are 

 organized beings can only be raised in relation to 

 the smallest species, those Micrococci which are 

 scarcely perceptible with the highest powers ; the 

 organized nature of the other organisms of the 

 same group has never been questioned, even by 

 the earliest observers, who all, since Leeunhoeck, 

 have, without exception, taken them for animals 

 or vegetables. But the smallest forms of bacteria 

 may be confounded with various matters, with 

 organic particles, molecular granules, fat globules, 

 etc. " These productions, which are found in con- 

 siderable quantity in the liquids or in the tissues 

 of animal or vegetable origin, often resemble so 

 closely, in form, size, and grouping, the spherical 

 bacteria, that it is absolutely impossible to guard 

 one's self against confusion, unless the most mi- 

 nute precautions are taken in making the observa- 

 tions " (Cohn). 



The detritus, the amorphous powder of precipi- 

 tated molecules of inorganic substances, even when 



