FOOD AND DIGESTION. 329 



d. Leguminous fruits are used by vegetarians, as the chief source of 

 the nitrogen of the food. Those chiefly used are peas, beans, lentils, 

 etc., they contain a nitrogenous substance called legumin, allied to 

 albumen. They contain about 25.30 per cent of this nitrogenous body, 

 and twice as much nitrogen as wheat. 



Organic non-nitrogenous foods. 



1. Carbo-hydrates. a. Bread, made from the ground grain obtained 

 from various so-called cereals, viz., wheat, rye, maize, barley, rice, oats, 

 etc., is the direct form in which the carbo-hydrate is supplied in an 

 ordinary diet. It contains starch, dextrin, and a little sugar. It also, 

 besides these, contains gluten, composed of several vegetable proteids, 

 and a small amount of fat. 



TABLE OF PERCENTAGE COMPOSITION OF BREAD AND FLOUR. 



Nitrogenous Carbo- 



.matters. hydrates. Fats. Salts. Water. 



Bread .... 8.1 51. 1.6 2.3 87 



Flour .... 10.8 70.85 2. 1.7 15 



Various articles of course besides bread are made from flour, e.g., 

 sago, macaroni, biscuits, etc. There is dextrine and a small amount of 

 dextrose in bread, particularly in the crust. 



b. Vegetables, especially potatoes. They contain starch and sugar. 

 In cabbage, turnips, etc., the salts of potassium are abundant. 



c. Fruits contain sugar, and organic acids, tartaric, malic, citric, 

 and others. 



d. Sugar, chiefly saccharose, used pure or in various sweetmeats. 



//. Oils and fats. The substances supplying the oils and fats of the 

 food are chiefly butter, bacon and lard (pig's fat), suet (beef and mutton 

 fat), and vegetable oils. These contain olein, stearin, and palmitin. 

 Butter contains others in addition, while vegetable oils, as a rule, con- 

 tain no stearin. 



Mineral or Inorganic Foods. 



The salts of the food. Nearly all the foregoing substances in the 

 preceding classes, contain a greater or less amount of the salts required 

 in food, but green vegetables and fruit supply certain salts, chiefly 

 potassium, without which the normal health of the body cannot be 

 maintained. 



Sodium chloride is an essential food; it is contained in nearly all 

 solids, but so much is required that it has also to be taken as a condi- 

 ment. Potassium salts are supplied in muscle, nerve, in meats generally, 

 and in potatoes. Calcium salts are supplied in eggs, blood of meat, wheat 

 and vegetables. Iron is contained in haemoglobin, in milk, eggs, and 



