_Iron_ is found in very small quantities in the human body, but it is absolutely essential to life. Animals deprived of iron die in a few weeks, and people will do the same under similar circumstances. Iron is obtained principally from fruits and vegetables, but it is also present in other foods. Man can not make use of inorganic iron. He has to get his supply from the vegetable and animal kingdoms. The giving of inorganic iron is folly and helps to ruin the teeth and the stomach of the one who takes it. In the form of hemoglobin this element is the chief agent in carrying oxygen from the lungs to the tissues of the body. In the manufacture of foods, much of the iron is lost. For instance, whole wheat flour contains about ten times as much iron as does the white flour. Too little iron causes, among other ills, anemia, and if the iron is very low, chlorosis or the green sickness may ensue. _Magnesium_ is found principally as phosphate in the bones. It is present both in animal and vegetable foods. Its function in the body is not well understood, but it appears to assist the phosphorus. _Silicon_ is found in traces in the human body. It is supplied in small quantities in nearly all of our foods, and therefore we must take it for granted that it is necessary, although we are in the dark as to its uses. It is very abundant in various rocks. The cereals are especially rich in silicon. In wheat it is found in the bran and is removed from the white flour. The elements mentioned are the most important in the body, though others are found in traces. We do not find the elements present as elements, but in the form of very complex compounds. Under our present conditions of living, we generally partake of too much carbonaceous and nitrogenous food, and get too little of the salts, except sodium chloride, which is taken in too great quantity. Salt, to most people, means but one thing, sodium chloride or table salt. However, there are thousands of salts, and when salts are mentioned in this book, all those necessary for the processes of life are meant, whether they be compounds of fluorine, sulphur, phosphorus, calcium, iron or magnesium or other metals and minerals. Salts are not usually classified as foods, but they are essential to life. Supply the body with all the protein, sugar, starch and fat that it requires, but withhold the salts, and it is but a question of a few weeks before life ceases. This is why it is so important to improve our methods of cooking. A potato that is peeled, soaked in cold water and boiled, may lose as much as one-half of its salts, according to one of the bulletins sent out by the U. S. Department of Agriculture. Other vegetables not only lose their salts by such treatment, but as high as 30 per cent of their nutritive value.