78 CHEMISTRY, GEOLOGY 



USE OF THE PRODUCTIONS OF THE SOIL. 



The productions of the soil are, to a large ex- 

 tent, designed for the food of animals. Animals 

 must obtain, from the food they eat, starch, 

 gluten, oil or fat, and saline or inorganic matter, 

 to be enabled to retain health and life. 



You will recollect that we proved starch to 

 contain carbon and water ; and, as water contains 

 hydrogen and oxygen, starch contains carbon, 

 hydrogen, and oxygen. Sugar also contains the 

 same elements, in a slightly-altered form of 

 combination ; and in gum the same elements 

 exist, but again changed in their proportions. 



Starch, or substances containing the same 

 elements, must form a part of the food of ani- 

 mals, to supply the carbon which they throw off 

 in the process of breathing. 



A healthy man throws off from his lungs 

 daily, in the form of carbonic acid gas, from six 

 to eight ounces of carbon ; hence, he must con- 



Questions. What is the great purpose of the produc- 

 tions of the earth ? What must animals obtain from their 

 ibod ? Of what is starch composed ? Does sugar con- 

 tain the same substances as starch ? Why must the food 

 of animals contain starch, or similar substances? How 

 much carbon does a man throw from his lungs daily ? 



