15S ON THE FOOD OF PLANTS. 



It seems to be generally admitted, that animal 

 and vegetable matter must be reduced to a per- 

 fectly soluble state, before it can be appropri- 

 ated as food for plants ; and to effect this, it is 

 considered necessary, that a perfect decompo- 

 sition should take place, of the substances pro- 

 vided for this purpose, and many processes are 

 noticed, by which a decomposition is effected ; 

 but that which is most generally considered as 

 the indispensable one, is the putrefactive fer- 

 mentation. There are, however, five distinct 

 stages of fermentation described by chemists ; 

 namely, the saccharine, or that which changes 

 coagulated mucus, or starch, into sugar; the vi- 

 nous, or that which forms alcohol, or spirit, from 

 sugar, and at the same time generates carbonic 

 acid ; the acetous, or that which forms vinegar 

 from sugar ; the colouring, or that which con- 

 verts the substance of the green indigo plant 

 into blue; and the putrefactive, which effects 

 the last and complete disunion of all the com- 

 ponent parts of a body ; leaving all at liberty to 

 form other combinations. 



Now all the different authors appear to concur 

 in the opinion, that the putrefactive ferment- 

 ation is a necessary process for the reduction of 

 animal and vegetable substances, to the requisite 

 state of food for plants; the other different stages 



