One of the important points to bring to the notice of pupils in the study of cookery is the phenomenon of nutrition. It is astonishing how vague are the ideas that many people have of why they eat food, and vaguer still are their notions of the necessity of air, pure and plenty. Once instruct the mind that it is the air we breathe and the food we eat which nourish the body, giving material for its various processes, for nervous and muscular energy, and for maintaining the constant temperature which the body must always possess in order to be in a state of health, and there is much more likelihood that the dignity and importance of proper cooking and proper food will not be overlooked.

A knowledge that the health and strength of a person depend largely upon what passes through his mouth, that even the turn of his thinking is modified by what he eats, should lead all intelligent women to make food a conscientious subject of study.

In general, by the term "nutrition" is meant the building up and maintaining of the physical framework of the body with all its various functions, and ultimately the mental and moral faculties which are dependent upon it, by means of nutriment or food.

The word is derived from the Latin nutrire, to nourish. The word "nurse" is from the same root, and in its original sense means one who nourishes, a person who supplies food, tends, or brings up.

Anything which aids in sustaining the body is food; therefore, air and water, the two most immediate necessities of life, may be, and often are, so classed.

Nutriment exclusive of air is received into the body by means of the alimentary canal. The great receiver of air is the lungs, but it also penetrates the body through the pores of the skin, and at these points carbonic acid is given off as in the lungs. The body is often compared to a steam-engine, which takes in raw material in the form of fuel and converts it into force or power. Food, drink, and air are the fuel of the body, - the things consumed; heat, muscular and intellectual energy, and other forms of power are the products.

Food, during the various digestive processes, becomes reduced to a liquid, and is then absorbed and conveyed, by different channels constructed for the purpose, into the blood, which contains, after being acted upon by the oxygen of the air in the lungs, all those substances which are required to maintain the various tissues, secretions, and, in fact, the life of the system.

Some of the ways in which the different kinds of food nourish the body have been found out by chemists and physiologists from actual experiments on living animals, such as rabbits, dogs, pigs, sheep, goats, and horses, and also on man. Often a scientist becomes so enthusiastic in his search for knowledge about a certain food that he gives his own body for trial. Much valuable work has been done in this direction during the last decade by Voit, Pettenkofer, Moleschott, Ranke, Payen, and in this country by Atwater.

No one can explain all the different intricate changes which a particle of food undergoes from the moment it enters the mouth until its final transformation into tissue or some form of energy; but by comparing the income with the outgo, ideas may be gained of what goes on in the economy of the body, and of the proportion of nutrients used, and some of the intricate and complex chemical changes which the different food principles undergo in the various processes of digestion, assimilation, and use.1 Probably l The body loses each day, in the performance of its ordinary and usual functions, about nine pounds of matter (Martin); therefore, that amount of income of food, water, and air will be needed in every twenty-four hours.

hundreds of changes take place in the body, in its various nutritive functions, of which nothing is known, or they are entirely unsuspected, so that if we do our utmost with the present lights which we possess for guidance to health, we shall still fall far short of completeness. The subject of food and nutrition, viewed in the light of bacteriology and chemistry, is one of the most inviting subjects of study of the day, and is worthy of the wisest thought of the nation.

The body creates nothing of itself, either of material or of energy; all must come to it from without. Every atom of carbon, hydrogen, phosphorus, or other elements, every molecule of protein, carbohydrate, or other compounds of these elements, is brought to the body with the food and drink it consumes, and the air it breathes. Like the steam-engine, it uses the material supplied to it. Its chemical compounds and energy are the compounds and energy of the food transformed (Atwater). A proof of this is seen in the fact that when the supply from without is cut off, the body dies. The raw material which the body uses is the air and food which it consumes, the greater portion of which is digested and distributed, through the medium of the blood, to all parts of the body, to renew and nourish the various tissues and to supply the material for the different activities of life.

Ways in which Food Supplies the "Wants of the Body. Food supplies the wants of the body in several ways - (1) it is used to form the tissues of the body - bones, flesh, tendons, skin, and nerves; (2) it is used to repair the waste of the tissues; (3) it is stored in the body for future use; (4) it is consumed as fuel to maintain the constant temperature which the body must always possess to be in a state of health; (5) it produces muscular and nervous energy.1 The l Prof. Atwater, in " The Century Magazine," 1887-88.

amount of energy of the body depends upon two things - the amount in the food eaten, and the ability of the body to use it, or free it for use.

With every motion, and every thought and feeling, material is consumed, hence the more rapid wearing out of persons who do severe work, and of the nervous - those who are keenly susceptible to every change in their surroundings, to change of weather, even to the thoughts and feelings of those about them.