FOOD. 21 



The different alimentary principles which are appropriated by the system 

 are combined in different proportions in the various articles of food, and 

 are separated from the innutritious substances during the process of diges- 

 tion. They belong to the organic and inorganic worlds, and may be 

 classified, according to their chemical composition, as follows : 



CLASSIFICATION OF ALIMENTARY PRINCIPLES. 



1. Albuminous group nitrogenized, C. O. H. N. S. P. 



PRINCIPLE. WHERE FOUND. 



Afyosin, syntonin, Flesh of animals. 



Vitellin, albumin, Yolk of egg, white of egg. 



Fibrin, globulin, Blood contained in meat. 



Casein, Milk, cheese. 



Gluten, Grain of wheat and other cereals. 



Vegetable albumin, Soft growing vegetables. 



Legumin, Peas, beans, lentils, etc. 



Gelatin, Bones. 



2. Saccharine group non-nitrogenized, C. O. H. 



Cane sugar, beet root sugar, . . Sugar cane, beets, etc. 



Glucose, grape sugar, Fruits. 



Itiosite, liver sugar, glycogen, . Muscles, liver, etc. 

 Lactose or milk sugar, .... Milk. 



Starch, Cereals, tuberous roots and leguminous 



plants. 



3. Oleaginous group non-nitrogenized, C. O. H. 



Animal fats and oils, . . . . ~\ Found in the adipose tissue of animals, 



Stearin, olein, . . > seeds, grains, nuts, fruits, and other 



Palm itin, fatty acids, . . . . J vegetable tissues. 



4. Inorganic group. Water, sodium and potassium chlorides, sodium, 

 calcium, magnesium and potassium phosphates, calcium carbonate and iron. 



5. Vegetable acid group. Malic, citric, tartaric and other acids, 

 found principally in fruits. 



6. Accessory foods. Tea, coffee, alcohol, cocoa, etc. 



The Albuminous principles enter largely into the composition of the 

 body, and constitute the organic bases of the different tissues; they are 

 mainly required for the growth and repair of the tissues. There is good 

 reason to believe that the albuminous principles are decomposed in the 

 body into fat and urea, and the former when oxidized gives ris'e to the 

 evolution of heat and force, while the latter is eliminated by the kidneys. 

 Muscular work, however, does not result from a destruction of the albu- 

 minous compounds. The oxidation of the carbonaceous compounds, sugars 



