CHAPTER XXXVH 

 FOOD 



Vocabulary 



Assimilated, made like and built into tissut. 



Calorie, the amount of heat used to raise a pound of water 4 deg. F. 



Ratio, proportion. 



Lipoid, a tissue building substance, somewhat like fats. 



Vitamines, active substances in some foods, necessary to health. 



All living things are alive because energy is liberated within 

 them. This energy depends upon oxidation and oxidation involves 

 the union of oxygen with the living tissue. This process destroys 

 the substances oxidized, leaving behind waste products, carbon 

 dioxide, water, and nitrogenous compounds, and necessitating 

 the replacement of the oxidized tissue. . Replacement of tissue 

 means the taking in of food, which is a vital necessity to all living 

 organisms. 



If food is assimilated faster than it is used, growth, or storage 

 of excess, results. In plants little energy is liberated and growth 

 may be continuous; in animals a point is reached where oxidation 

 balances assimilation and growth practically ceases. 



Definition. Food may be denned as any substance which, when 

 taken into a living organism, produces energy or builds tissue. 

 The energy is necessary for any life, the tissue building may be to 

 repair used organs or for increase in growth. 



The chemical composition of all living things is much the same. 

 They are composed of a small number of elements and all depend 

 upon the vitality of protoplasm for their life. (See ch. 3, 4, 5.) 



Naturally the foods that produce these living tissues are also 

 similar in composition, though numerous in kind. The general 

 classes of food stuffs (nutrients) have been discussed in Chapter 4, 



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