THE SPIRIT OF THE SOIL 



CHAPTER I 



THE NITRATE PROBLEM 



Geometric progression illustrated by bacterial growth Geo- 

 metric character of advancing civilization Latter-day 

 developments Present prosperity Threatened famine in 

 power and nitrates Science to the rescue Sources of 

 plant food Cavendish and Bunsen Electrically produced 

 nitrates A nitrate balance - sheet The outlook In- 

 creased demand Diminished supply threatened Bacteria 

 as nitrate builders Their use in agriculture. 



PICTURE an observer suspended above the equator 

 of the earth, unaffected by the swirl due to the 

 earth's turning on her axis, but following closely 

 her movements through space. Assume that at an 

 instant in time he drops a bacterium on the hurry- 

 ing surface beneath his feet, and that the bacterium, 

 like the seed of the sower that fell on fruitful ground, 

 falls into a medium ideal for its growth and finds 

 nothing to check its power of reproduction. In 

 twenty-four hours, when the same spot of the 

 earth's surface was again beneath his feet, he would 

 find, instead of the single bacterium he had dropped, 

 a bacterial empire one hundred and seventy thousand 

 times as numerous as the present human population 



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