l66 AGRICULTURE OF MAINE). 



oxygen and the hydrogen, forming water. It is found in the 

 body, too. In a considerable portion of all animal and vegetable 

 matter hydrogen is found. That, too, serves as fuel. The ni- 

 trogen is found in most animal and most vegetable matter, but 

 not in all. It is not so universally found as the others. In the 

 different magazine articles and the different books dealing with 

 foods, we find food principles mentioned. We find there are 

 five food principles, they being the foundation work of the study 

 of domestic science or home economics. 



The first of these principles we will consider as water. The 

 second will be protein, the third fat, the fourth carbohydrates, 

 and the fifth of them, found in small quantities, is the most im- 

 portant thing and that is the mineral matter. 



Water is the important constituent of the make-up of the 

 body. Sixty-one per cent of the body is composed of water. 

 With the mineral matter we find that we have phosphate of lime 

 and sodium and potassium, all necessary for the formation of 

 food, consequently very necessary for adults, and also for small 

 children where the growth of the bone is of so much importance. 



We find an example of the fats in olive oil, and we find ani- 

 mal fat. The carbohydrates, taking the starch and sugar, are 

 found in all plants. We know there is a very important frame- 

 work in plants. Perhaps we could see it more clearly in veg- 

 etables. That framework is called the cellulose, and that comes 

 under the carbohydrates. Protein is the most important of the 

 five constituents. A good example of protein is the albumen 

 of the egg — the white of the egg — or the gluten of wheat. The 

 gluten is developed in the process of bread-making when water 

 is added to the flour, and makes it possible to have bread formed. 

 Another example of protein is casein in cheese. We want to 

 consider that cheese is one of the most important protein foods 

 we have. And as housewives if we can provide cheese in dif- 

 ferent forms, provided the members of the family can digest it 

 readily, it is an excellent protein food. 



With regard to the composition of the food materials, we can 

 consider them in the raw material, under two heads, the non- 

 nutrients and the nutrients. The non-nutrients are those that 

 do not benefit us in any way, like the refuse we find in all foods, 

 bones in animals, the bran in bread, shells and potato skins and 

 banana skins. The amount of waste varies greatly in different 



