754 Reading-Course for Farmers' Wives. 



of the amounts of these foods in the diet when we consider the daily 

 food need. 



If more fat, sugar or starch is consumed than is required for the body's 

 needs and if at the same time the amount has not been so great as to 

 overtax the power of the body to absorb and assimilate it, the excess 

 may be stored in the body, temporarily, in a form known as glycogen 

 o,r body starch, and more permanently as fat. Fat deposited in the 

 tissues serves as a reserve food supply for the body to call upon in case 

 of need. If less fuel is consumed than is needed for the day's energy, 

 the. body burns some of its own tissue to make good the deficit. The 

 waste products of the fats and carbohydrates are comparatively simple 

 and are gotten rid of through the lungs in the breath and, by means of 

 perspiration, through the skin. 



Protein. — Nitrogen is essential to the building up of all living tissue. 

 The substance of the cell itself contains nitrogen. The fats and carbo- 

 hydrates are very valuable fuels to the body, but by themselves they 

 cannot furnish building material for its living parts. Compounds which 

 contain nitrogen are necessary for the existence and persistence of all 

 the living cells. The only form of nitrogen which is available to man 

 for this purpose is in a class of substances known as the proteins. Some 

 common examples of protein are the white of egg (albumen), the 

 curd of milk (casein), the lean of meat (myosin), and the elastic 

 substance in wheat (gluten). The white scum which rises on preserves 

 when they are cooking is a vegetable albumen which has flowed into the 

 Avater from the tissues of the plant and which in common with many 

 proteins hardens on cooking, just as the white of egg hardens in hot 

 water. Proteins are compounds always containing the five elements, 

 nitrogen, carbon, hydrogen, oxygen and sulfur. They are not only 

 vital to the formation of living tissues, but being rich in carbon, they 

 are also sources of energy to the body. In other words, protein may 

 serve as a fuel as well as a building material for it contains carbon as 

 well as nitrogen. The proteins should not be depended upon as a main 

 source of energy, however, for they are not only expensive but if used 

 in this way may soon prove exceedingly harmful to the body. The foods 

 which are relatively rich in protein substances are : 



Milk Cheese Some Cereals 



Eggs Nuts 



Aleat Legumes 



The question of protein is an exceedingly important one, for this food 

 compound forms the basis of all living substance and yet if consumed 



