Food from the Soil lay 



Wherever these nitrates are formed, whether, as in 

 England, they are dissolved almost at once, or whether, 

 as in dry lands, they accumulate and encrust the soil, they 

 are formed by the decay of animal and vegetable matter. 

 And what, it may be asked, causes this decay? Not the 

 action of the air; for in perfectly pure air organic sub- 

 stances do not decay. The change is brought about by 

 the action of living organisms, invisible, but very potent 

 in their effects. 



We have all heard enough about "germs" of late to 

 know that they swarm in the air; but they also swarm in 

 all the moist places of the earth. Some few classes of 

 them are dangerous to man, and produce diseases of vari- 

 ous kinds; others are not only harmless, but productive 

 of the greatest good. 



All decay, fermentation, or putrefaction, whichever we 

 call it, is their work; and when we say ''work," all that 

 is meant is their living, growing, multiplying, which they 

 cannot do without feeding. There is an immense variety 

 of them, and they produce different results, according to 

 their different modes of feeding. The yeast which is put 

 into dough, the "mold" which grows upon paste, or jam, 

 are all of similar nature, and all produce alterations in the 

 substance which they attack. When we like the result of 

 these alterations, we call the process "fermentation"; and 

 when we do not like it, we call it "putrefaction"; but 

 both are substantially the same, for both are the result of 

 decomposition. Grape-juice, apple-juice, and wort are 

 converted by these "ferments" into wine, cider, and beer 

 respectively; and another ferment again alters wine yet 

 further, and turns it into vinegar. 



It is these living organisms which bring about all decay 



