THE BACTERIA IN DIFFERENT MEDIA. Ray! 
truly an organized ferment. Indeed, chloroform, 
this anzesthetic, suspends nitrification, and seems 
even to kill the ferment. 
Leaving, then, this phenomenon, but little 
known, we may distinguish in the agents of pu- 
trefaction, or more generally of fermentation, two 
groups of micro-organisms, — one oxidizing, the 
other reducing. 
The first are observed upon the surface of 
liquids undergoing putrefaction. We may distin- 
guish a great number of forms,— Bacterium termo, 
Monas crepusculum, Spirillum, etc. We ought 
also to include Mycoderma aceti, which, like the 
others, vegetates on the surface of liquids, and 
a great number of organisms of which we cannot 
speak here. 
The second are met, on the contrary, in the 
interior of liquids or of fermentable bodies; they 
are analogous to the butyric and lactic ferments, 
and perhaps to the other agents of diseases of 
wine and beer previously enumerated. 
En resume, the little beings which we have been 
considering have an important role: they cause 
the return of dead organic matter to the atmos- 
phere and to water. 
“ Without them, organic matter, even exposed 
to the air, would not be destroyed or would be 
transformed with extreme slowness, in consequence 
of a slow combustion produced by oxygen. With 
them, on the contrary, its destruction takes a 
rapid march and becomes complete. If, then, the 
equilibrium is maintained between living nature 
