THE STORY OF OUR FOODS 17 



particular element makes all the difference in the 

 world in the character of a food. For as the living 

 matter or protoplasm of our bodies is a nitrogenous 

 substance, and as protoplasm is one of the most 

 important elements demanding repair, these foods 

 therefore come to represent in the most typical 

 fashion our body-building items. If we make out a 

 list of the substances on which we subsist, we shall 

 find them to consist of (1) water, (2) minerals, 

 (3) starches and sugars, and (4) fats. These represent 

 the non-nitrogenous foods, while the (5) nitrogenous 

 foods complete the list. Water and minerals are in 

 one sense "body-building" items, because, as we 

 shall see, water enters into the composition of every 

 tissue and fluid of our frame, whilst minerals also 

 play an important part both in building and in main- 

 taining the welfare of the body. Nitrogenous foods, 

 on the other hand, are represented by various 

 principles contained in many foods derived both 

 from the animal and plant worlds, such foods 

 containing other substances in addition to their 

 nitrogenous matters. As examples of the nitro- 

 genous class we may take albumen, represented by 

 the juice of meat and white of egg; casein, 

 represented by the curd of milk; gluten, found in 

 flour and vegetable matters at large; and legumin, 

 specially found in peas, beans, and lentils. These 

 principles are associated, as has been noted, with 

 other foods. For example in peas, beans, and 

 lentils, we also find starch, a certain amount of 

 fatty matter, and minerals along with water, which 

 last we may take for granted is found in foods of all 

 descriptions. Gluten, found in bread, is associated 

 with starch, a small amount of fat, minerals, and 

 water. Beef and other forms of flesh-building 



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