CHAPTER XII 

 ANIMAL FOOD 



153. Food elements. Anything which, taken inside of 

 the body, supplies it with weight, heat, or energy is food. 

 Man's food consists of a great variety of substances de- 

 rived from the animal, vegetable, and mineral kingdoms. 

 Yet all food consists of the proximate principles : water, 

 mineral matter, albumin, fat, and starch or sugar. Neither 

 alone makes a perfect food, but all must be present in 

 proper proportions or else the body will suffer. 



154. Water. Water requires no digestion, but is con- 

 tinually entering and leaving the body unchanged in form. 

 All solid food contains some water, and enough more is 

 added in liquid food and in drink to supply the full needs 

 of the body. Twelve or fifteen pints of fluid are used 

 daily in the work of digestion, but it is absorbed back 

 again to the blood and so little is lost. Within reasonable 

 limits, water taken at meal times aids digestion. In order 

 to digest food and wash away waste matter properly, two 

 or three quarts must be swallowed daily. If the thirst is 

 satisfied with pure water, there will be little danger of 

 taking too much, and the indications of thirst will be the 

 most reliable guide as to the times of drinking and of the 

 quantity required. 



155. Mineral matters. Mineral matters are not changed 

 during digestion, and they leave the body in the same form 

 in which they enter. More than enough are found in all 



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