Our knowledge of vitamins has given a new basis for the evaluation of foods. Certain articles which, from the point of view of their energy value, are almost worthless have been shown to possess great nutritive value. Their importance is not suggested by their chemical analysis. They furnish something very essential in a human diet.
The tomato, cabbage, spinach, lettuce, chard and all the green or leafy vegetables are composed chiefly of cellulose, water and inorganic salts. Fruits have sugar, vegetable acids, water and salts, but none of these things suggest their essential value as foodstuffs.
Many of our foods we no longer eat in their natural state. The conditions of modern life have made necessary the transportation of foods for long distances and the preservation and storage of food in immense quantities for long periods. A certain amount of injury is done to our vegetables, fruits, milk, meats and