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, 3.nd 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 faBcal 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. AU our fermented liquors, wine, beer, 

 vinegar, etc., are artificially produced by the species 

 of microbes called ferments; they also cause bread 



