136 TEXT-BOOK OF PHYSIOLOGY. 



From the above it will be observed that the daily discharge for 

 each kilogram of body- weight is 0.21 gram nitrogen and 3.03 grams 

 of carbon; the relation of the two being ^ = 14.5. On a diet in 

 which there is an excess of either proteid or carbohydrates this ratio 

 necessarily changes. 



CLASSIFICATION OF FOOD PRINCIPLES. 



Though the food principles are grouped as proteids, t fats, carbo- 

 hydrates, etc., the members of each group differ somewhat in chemic 

 composition, digestibility, and nutritive value. These groups are as 

 follows: 



i. PROTEIDS. 



Principle. Where found. 



Myosin, __________________________ Flesh of animals. 



Albumin, vitellin, __________________ White of egg, yolk of egg. 



Caseinogen, _______________________ Milk. 



Serum-albumin, fibrin, _____________ Blood contained in meat. 



Glutin, ___________________________ Grain of wheat and other cereals. 



Vegetable albumin, ________________ Soft-growing vegetables. 



Legumin, _________________________ Peas, beans, lentils, etc. 



2. FATS. 



Animal fats, ______________________ In adipose tissue of animals. 



Vegetable oils, _____________________ In seeds, grains, nuts, fruits, and other 



vegetable tissues. 



3. CARBOHYDRATES. 



Dextrose or grape-sugar, _ _ -------- ) , f . 



Levulose or fruit-sugar, __________ j U 



Lactose or milk-sugar, ______________ Milk. 



Saccharose or cane-sugar, __________ Sugar-cane, beet roots. 



Maltose, __________________________ Malt and malted foods. 



Cf u I Cereals, tuberous roots, and legumin- 



Starch, ------------------------ ^ ous plants. 



Glycogen, ------------------------ Liver, muscles. 



4. INORGANIC. 

 Water, 



" animd and vegetab.e 



phosphates and carbonates, 

 Iron, 



5. VEGETABLE ACIDS. 



Citric, tartaric acetic, malic, ________ In fruit and vegetables. 



6. ACCESSORY FOODS. 

 Coffee, Tea, Cocoa, Alcohol. 



