116 MICROBES, FERMENTS, AND MOULDS. 
ammoniacal salts, and consequently constitutes a 
strong manure, very fit to serve as the ‘nutriment of 
plants. 
This is at once the beginning and the termination 
of the endless chain which sustains the equilibrium 
of nature, in which there is no creation, no destruction. 
Plants draw their nutriment from the soil and the air 
in the form of mineral solutions, and are devoured 
by animals or by other parasites; animals are in their 
turn devoured by microscopic plants or microbes, and 
return by means of putrefaction to the condition of 
mineral salts, which are distributed in the soil, and 
servé anew for the nutrition of plants. 
We must at the same time be struck by the 
resemblance which exists between these phenomena 
of putrid fermentation, and those which occur in the 
fermentations which accompany the nutrition of 
animals and plants. Germination and the different 
digestions which occur in the mouth, the stomach, 
the intestines, etc., are only fermentations, so that 
Mitscherlich has paraphrased the Scripture saying, 
“Dust thou art, and unto dust thou shalt return,” 
by declaring that “ Life is only a corruption.” 
It should, however, be remembered that fermenta- 
tions are essentially phenomena of disintegration, 
which always reduce complex, organic substances to 
those which are simpler. Plants provided with 
chlorophyl, on the other hand, alone possess the 
property of forming higher organic compounds, by 
