CHAPTER II 

 Some Physiology You Ought to Know 



A close relation exists between the soil, plant, 

 and the animal. One really cannot exist without 

 the other to fulfill its destiny. A soil without plant 

 or animal growth is barren, devoid of life. The 

 soil comes first; the elements contained in it and 

 the air are the basis of plant and animal life. The 

 body of the animal is made up of the identical 

 elements found in the plant, yet the growth of the 

 plant is necessary to furnish food for animal life. 

 The plant takes from the soil and from the air the 

 simple chemical elements, and with these builds up 

 the plant tissue which, in its turn, is the food of 

 the animal. 



The animal cannot feed directly from the soil and 

 air; it requires the plant first to take the elements 

 and to build them into tissue. From this tissue 

 animals get their food for maintenance and growth. 

 Then the animal dies; with its decay and decom- 

 position comes change of animal tissue, back to 

 soil and air again ; back to single simple elements, 

 that new plants may be grown, that new plant tis- 

 sue may be made for another generation of animal 

 life. 



Thus the plant grows out of the soil and air, 

 and the decay of the animal plant life furnishes 

 food for the plant that the plant may furnish food 

 for the animal. Thus we see the cycle of life ; from 

 the soil and air come the soil constituents. 



Meaning of Plant Building.— Before the single 

 simple elements were taken into the plant, they 



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