Mineral matter of food is left in the form of ash when the food is burned. The mineral matter of the body consists of calcium phosphate and compounds of sodium, potassium, magnesium and iron. These are found principally in the bones, though the blood and muscular fiber also contain mineral matter. Mineral matter is found in all naturally occurring foods, though manufacturing processes may produce food products, such as sugar and olive oil, from which the mineral matter has been practically all removed.

The mineral matter of the food is taken by the body to make bones and perform the other functions for which it is needed. The production of heat or power is not considered as one of the uses of mineral matter.

Water-More than half the weight of the human body is water. It is present in all parts of the body. It cannot furnish heat or energy, but is absolutely essential to life. It plays an important part in the digestive processes, in the distribution of the food material to the different parts of the body and in maintaining the body at a uniform temperature. It is an

important constituent of all natural foods, though manufacturing processes result in eliminating it partly or wholly from many foods. The more water there is in a food the less there is of fat, carbohydrates, protein and mineral matter which furnish the heat, energy and building material to the body.

These different classes of food materials generally occur combined in natural products but the relative amount of the different substances vary in different foods, and in some products one or more of them may be entirely absent.

H

The average human body contains about 15 per cent fat, 18 per cent protein, carbohydrates 1 per cent, mineral matter 6 per cent and water 60 per cent.

The charts printed herewith give optional illustrations of the relative amount of these different constituents in some of the common foods. The source of the charts is indicated in each. The cuts were furnished by the Hotel Monthly. The term fat, carbohydrates, protein mineral matter and water as used in these charts have already been explained in a simple way.

There are two other terms which need explanation perhaps. As has been explained, the fat, carbohydrates and protein of the food may be actually burned up in the body, becoming the fuel to keep it warm and give it power. Now, any fuel gives out a definite quantity of heat when it is burned, and the value of the fuel is determined by the amount of heat produced by a pound of it. The amount of heat is measured by its effect in raising the temperature of a body of water. As a pound is the unit for measuring