CHAPTER XXVI 

 FOODS AND THEIR USES 



After the food is digested and absorbed it is carried by 

 the blood and lymph to various parts of the body where the 

 different organs convert it into their own peculiar sub- 

 stance. This conversion is the process of assimilation, 

 to which digestion and absorption were merely prepara- 

 tory. It is one of the most wonderful as well as one of the 

 least understood of the activities which take place in the 

 living organism. Assimilation not only compensates 

 for the waste that is always being produced by the body, 

 but it enables the body to increase in size. When waste 

 is exceeded by repair as in the normal small boy there is 

 growth. In a fever when the tissues are rapidly consumed, 

 or burned, there is loss of weight; this may be very marked 

 if the fever is severe. Growth is rapid in the early years 

 of life and a relatively large amount of food is required as 

 is evinced by the keen and frequently recurring appetite 

 of healthy youth. 



The many articles of diet which we consume are quite 

 different in their chemical composition and they are put to 

 different uses in the economy of the body. The true living 

 substance, or protoplasm, requires for its formation foods 

 which contain all the necessary chemical elements. Since 

 proteins contain nitrogen (this element is absent in carbo- 

 hydrates and commonly in fats) a certain amount of pro- 

 tein is absolutely necessary for the continued maintenance 

 of life. Fat in the body may be derived from carbo- 

 hydrates or from other fats. Many people find sugar and 



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