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. Stn 
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 alga 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 Micrococct 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 
4 
