The structure of vegetables controls somewhat the manner of cooking. Rapid, hard boiling is needed for very much incased vegetables, as asparagus, especially if also delicately flavored. Baked food cooks in steam generated from the water in the food itself. The salts of foods are thus retained and the starch is more fully transformed for digestion.

In cooking, physical structure changes, germs are destroyed, flavor is preserved or modified, preparation for digestion begins.

The indigestible material in a food affects its nutritive value in several ways. The separation of it from the nourishing substances is an essential precaution in food-preparation. Cook-ing, grinding or chopping, masticating, dissolving, aid?

Raw food needs great care. Its freshness is of real value.

Vegetables should be clean themselves, kept so, and handled by no diseased persons. Decaying vegetables are unwholesome. The effect of unsoundness spreads beyond the parts seen as unsound. It rarely can be wholly removed by removing these. Germ-development is prevented by low temperature, pure dust-free air, and sunlight. Pure water too is protective against germs, so long as it remains pure.

Intelligent care of food is a health-help, also an economy.

What humanity has found suits its need is disclosed by the food-supply. This is general advice from race-experience. Living acquaints one with this. But only learning what each food is and does can teach when each should be used. Seasons and stages of development are given with the specific foods. Grains are more closely related in composition to leguminous vegetables than to other vegetable foods. They serve similarly in the diet. Fruits, spices, nuts, differ somewhat from grains and vegetables and serve different food-purposes.