[AS.] All substances used for purposes of nutrition. The useful constituents of all foods - animal, vegetable, and mineral - are classified as (1) nitrogenous, including the animal and vegetable albuminoids and gelatin; (2) fatty, including animal and vegetable fats and oils; (3) carbohydrates, including starch and the sugars ; (4) salts fly's foot magnified.

organic and inorganic; (5) water. In addition to the vegetable and animal foods consumed for the support and growth of the body, there are also needed lime, iron, soda, potash, chlorides and phosphates, etc. Water is very necessary, since it forms two-thirds of the weight of the body. A very great variety of foods and combinations of nutritive materials are used by man.