When we consider the fact that the body is made up of various tissues, such as connective tissue, blood, nerves and muscles; that these in turn are made up of billions of cells, as are the various glandular organs and membranes; that these cells are constantly bathed in blood and lymph, from which they select the food they need and throw the refuse away, we must marvel that an organism so complex is so resistant, stable and strong. All articles of good quality are made by first-class workmen from fine materials. However, many people fail to realize that in order to have quality bodies they must take quality food, properly cooked or prepared, in the right proportions and combinations. If we feed the body properly, nature is kind enough to do good constructive work without any thought on our part. You will find no rigid rules in these talks on diet, but you will find information that will enable you to select foods that will agree with you. People may well disagree on what to eat, for there are so many foods that a person could do without nine-tenths of them and still be well nourished. In fact, we consume too great a variety of food for our physical well-being. Great variety leads to overeating. A healthy human body is composed of the following compounds, in about the proportions given: Water, 60 to 65 per cent. Mineral matter, 5 to 6 per cent. Protein, 18 to 20 per cent. Carbohydrates, 1 per cent. Fat, 10 per cent. This is perhaps excessive. These substances are very complex and well distributed throughout the body. They are composed of about sixteen or seventeen elements, but a pure element is very rarely found in the body, unless it be a foreign substance, such as mercury or lead. About 70 per cent of the body is oxygen, which is also the most abundant element of the earth. Then in order of their weight come carbon, hydrogen, nitrogen, calcium, phosphorus, sulphur, sodium, chlorine, fluorine, potassium, iron, magnesium and silicon. Because it will be helpful in giving a better idea of the necessity for proper feeding, I shall devote a few words to each of these elements. _Oxygen_ is a colorless, tasteless, odorless gas, forming a large part of the atmospheric air, of water, of the earth's crust and of our foods. It is absolutely essential to life, for without oxygen there can be no combustion in the animal tissues, and without combustion there can be no life. The union of oxygen with fats, carbohydrates and proteins in the body results in slow combustion, which produces heat and energy. Our chief supply of oxygen comes directly from the air, but this is supplemented by the intake in food and water.