AND AGRICULTURE. 



27 



Plants obtain their food in part from the air, 

 and in part from the soil : their leaves drink it 

 in from the air, and their roots take it up from 

 the soil. Nor can they thrive alone upon one 

 kind of food : they must have two distinct kinds 

 of food ; they must have organic food to support 

 their organic part, and inorganic food to 

 strengthen their inorganic part. Their organic 

 food is derived from the air and the soil ; their 

 inorganic food is obtained from the soil alone. 



Fig. 11. 



Fig. 10. 



Questions. Where do plants obtain food ? How do they 

 obtain it ? How many kinds of food do they need ? Where 

 do they get their organic food ? Where their inorganic food ? 



