28 HUMAN PHYSIOLOGY CHAP. 



drate ; about one eighth of a pound of salt ; and from 

 three to five pounds of water. The foods we eat each 

 day should be so selected as to yield this amount of 

 each food stuff if we wish to be in good health. 



SUMMARY OF THE MAIN POINTS 



i. A food is any substance that enters the blood, and with- 

 out doing any harm in the body helps to cause growth, to re- 

 pair the cells, and to yield heat and energy. 



2. The food stuffs are proteids, carbohydrates, fats, salts, 

 water, and oxygen. These food stuffs are oxidized in the cells 

 of the body. 



3. Proteids are the tissue-building and tissue-repairing 

 foods. They are essential to life. 



4. The carbohydrates form the great bulk of our daily diet. 

 They serve to yield heat and energy. 



5. The fats are the greatest heat producers, but are not as 

 valuable as the carbohydrates, because they are more difficult 

 to digest. 



6. Water is found in all of the foods we eat, but that does 

 not meet the demand of the body. We must drink considera- 

 ble water each day, for it has many uses in the body. 



7. Water dissolves the solid foods, moistens the mouth and 

 other organs to aid in swallowing, makes up a large part of the 

 blood and lymph, and is an essential part of each cell. 



8. The cells cannot do their work properly unless consid- 

 erable salt is present. 



9. Foods are of no use to the body without oxygen; but 

 when foods and oxygen are brought together in the cells, heat is 

 produced and tissues may be built up and repaired. 



10. Mustard, ginger, pepper, pickles, olives, vinegar, horse- 

 radish, and all flavors are not true foods, and when taken in 

 excess prove harmful. 



