6 MICROBES, FERMENTS, AND MOULDS. 
link, and testify to the common origin of the two 
great organic kingdoms. 
However this may be, we shall make use of the 
word “microbe” as the general designation of all 
the minute organized beings which are found on the 
borderland between animals and plants. We shall 
presently show that in the majority of cases these 
beings may be regarded as true plants, and this is at 
present generally admitted by most naturalists. 
Part played by Microbes in Nature.—The part 
played by microbes in nature is an important one. 
We find them everywhere ; every species of plant has 
its special parasites, and this is also the case with our 
cultivated plants—with the vine, for example, which is 
attacked by more than a hundred different kinds. 
These microscopic fungi have their use in the general 
economy of nature; they are nourished at the expense 
of organic substances when in a state of putrefac- 
tion, and reduce their complex constituents into those 
which are simpler—into the soluble mineral substances 
which return to the soil from which the plants are 
derived, and thus serve afresh for the nourishment of 
similar plants. In this way they clear the surface of 
the earth from dead bodies and faecal matter; from all 
the dead and useless substances which are the refuse 
of life, and thus they unite animals and plants in an 
endless chain. All our fermented liquors, wine, beer, 
vinegar, etc, are artificially produced by the species 
of microbes called ferments; they also cause bread 
