CHAPTER VIII 

 ALIMENTATION AND DIGESTION 



A. THE SUPPLY OF MATTER AND POWEK TO THE 

 HUMAN MACHINE 



1. Power and the materials for repair supplied separately 

 to lifeless machines. Living and lifeless machines are alike 

 in that worn-out parts must be renewed and that power 

 must be supplied to do work. In the lifeless machine these 

 two requirements are supplied separately. A factory and 

 its equipment of machinery are kept in repair and enlarged 

 (grow) by means of bricks, lumber, steel, belting, new pieces 

 of machinery, etc., which are brought into the building, 

 while the power which runs the machinery comes in quite 

 separately as fuel, or water power, or electric power. 



2. Power and the materials for growth and repair supplied 

 to the human machine in the one form of foods. With the 

 human mechanism this is not so. Materials for growth and 

 repair, and power for running, are introduced from without 

 not separately, but together, both being supplied in the one 

 form of food. As it does its life work the human mechanism, 

 like a lifeless machine, not only consumes power but its parts 

 deteriorate, and it is the double function of the food we eat 

 to make good this double loss. Some foods possibly serve 

 only as means of power; others merely make good the loss 

 of essential parts of the mechanism; while still others may 

 serve both purposes. 



3. Food as a source of power. Experiment and experience 

 alike prove that foods are the source of power for work. 

 Bread, butter, starch, sugar, beef, and the like may be dried 



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