FOODS AS BUILDING MATERIALS 9 



body are proteids, fat, starch, sugar, and mineral mat- 

 ter such as salt, lime, iron, and phosphorus. Proteid 

 is derived from a Greek word which means first. 

 It is justly entitled to this name, for it is the most 

 important of the body's building materials. Since 

 blood, muscle, and all the vital organs contain pro- 

 teids as their chief component, we can readily under- 

 stand why much of our food should be rich in this 

 material. 



What is proteid like? Is it something that only 

 college professors and students with costly microscopes 

 can find and understand, or is it possible for school 

 children to get acquainted with this important sub- 

 stance ? Strangely enough many of our old friends in 

 the food family contain much of this useful material. 

 For instance, the white of egg, often called albumen, 

 is largely composed of it. Lean meat, the curd of 

 milk (the part from which cheese is made), the gluten 

 of flour, the legumen of peas and beans, are all good 

 examples. 



Proteids contain a great deal of an important 

 element called nitrogen, and for this reason are often 

 spoken of as nitrogenous foods. While proteids can 

 take the place of fats, starch, and sugar in supplying 

 fuel and energy to the body, these foods cannot take 

 its place in forming new tissues. On this account we 

 should plan always to have plenty of proteids in our 

 food. 



