Food and Drink 8 1 



The principal proteid foodstuffs are milk, eggs, flesh 

 foods of all kinds, fish, and the cereals among vegetable 

 foods. Peas and beans are rich in proteids. 



The essential use of the proteids, or nitrogenous food- 

 stuffs, to the tissues is to supply the material from which 

 new tissue is made or old tissue is repaired. They are also 

 valuable to the body as sources of energy. Now, as pro- 

 teids are the most important constituents of living matter, 

 it is evident that proteid food is the essential element of all food. 

 In short, if our diet contained no proteids, the tissues of the 

 body would gradually waste away, and death would sooner 

 or later result. 



119. Starches and Sugars. The starches, sugars, and 

 gums, also known as carbohydrates, enter largely into the 

 composition of foods of vegetable origin. They contain 

 no nitrogen, but only the three elements, carbon, hydrogen, 

 and oxygen. 



The starches are abundant in potatoes and the cereals, 

 and in arrowroot, sago, and tapioca. 



The sugars are also widely distributed substances, and 

 include cane, grape, malt, maple, and milk sugars. To this 

 group of carbohydrates also belong the gums and the 

 cellulose or woody fibrous substance found in fruit, cereals, 

 and all vegetables. Honey and molasses are likewise 

 carbohydrates. 



The starches and sugars are oxidized in the body, and a 

 certain amount of energy is thereby liberated. The energy 

 of muscular work and of the heat of the body comes largely 

 from their oxidation. 



120, Fats and Oils. These include not only the ordi- 

 nary fats of meat, but many animal and vegetable oils. They 

 are rich in carbon and hydrogen, but contain little oxygen. 

 The principal kinds of fat used as food are the fat of meat, 



