CHAPTEE III. 



DIETETICS, HYGIENE, AND REGIMEN. 

 Chemistry — Quality and Quantity of Food — Water— Oats — Corn. 



Baron Liebig compares fhe bodies of animals to a loco- 

 motive engine, in which air, water, and fuel, working, 

 together, generate heat and power. The food is the fuel, 

 without which the machinery would be useless. The food 

 and water supply the material necessary to repair what is 

 lost by wear and tear of the machine. He says there are 

 three conditions necessary to constitute food of perfect 

 quality : a certain quantity of albumen (a familiar illustra- 

 tion of which is the white of egg), furnishing an imjDortant 

 constituent to the blood, and is also the material of all the 

 plastic portions of the body — a proportion of heat-giving 

 substances, chiefly appropriated in the vital process, and 

 nutritive salts, without which the- other two cannot give 

 nourishment. Any one of these substances alone could 

 not support life, and only in that food where they are 



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