Even when the body seems to be quite still, movement is going on in every part of it. The blood is constantly being pumped by the heart, and carried to all parts of the body; the lungs move with every breath ; a change is caused in the brain by every thought. To produce movement, either external or internal, some force or exertion (not necessarily voluntary) is used, and all force involves wear and tear. This wear and tear takes place in the flesh and blood, the fat and bones, and other materials of which the body is composed. If these used-up materials are not replaced, the body will wear away, and the animal become exhausted and die. All living human bodies are warm.1 If the warmth 1 The temperature of th6 human body is about 98° Fahr. , and in healthy persons is nearly uniform both in hot and in cold weather. Thermometers, instruments formeasuringheat, have been constructed by various persons : the one made by Fahrenheit is in most general use. Freezing point is 320 (° means degrees); temperate, 55°; summer heat, 76°; blood heat, 98°; boiling point (water), 213°. 8 INTRODUCTION. is not kept up they die. In keeping up this warmth something is used up, and this must be replaced. Food replaces the materials used up by the move- ment of our bodies, keeps up warmth, and gives power of movement, or, as it is more correctly called, force. Food cannot, however, accomplish these ob- jects in its natural state. It must be reduced into a lluid form so as to be able to pass through very small channels, and to be carried along in the blood. After it enters the bloodvessels it must mix with air,1 drawn in through the lungs and skin, and through the changes effected by the air and by various other organs of the body, the food is gradually made fit to replace all wasted and worn-out materials. I he wholesomeness of food depends on three con- ditions : — 1. On the selection of the right materials, whether animal or vegetable, and on their use in proper pro- portions. 2. On cooking the materials in such a manner as to make them digestible, — that is, capable of being readily turned into material fit for replacing the waste of the body already spoken of. 3. On adapting the use of food to the different cir- cumstances of age, employment, climate, and state of health. 1 That part of air called oxygen. THE MATERIALS OF FOOD. 9 CHAPTER I. THE MATERIALS OF FOOD. Before learning the principles of Cookery, it is impor- tant to know something about the composition of the different kinds of food, in order to choose those that are best fitted to keep the body in health and vigour. For this purpose let us consider one or two of our most important foods. Milk is the most perfect human food that we have; infants live on it alone. We find that if milk stands for a little, the cream or fatty part separates and rises to the top, leaving the skim milk below. The cream is the principal part which gives warmth, but it does not repair the used-up materials of the body. The skim milk does this. Skim milk can be separated into curd and whey. Curd is, strictly speaking, the flesh- forming part : whey supplies water, sugar, and mineral substances.

AI-modernized reading of the original text

Even when the body seems to be quite still, movement is going on in every part of it. The blood is constantly being pumped by the heart, and carried to all parts of the body; the lungs move with every breath ; a change is caused in the brain by every thought. To produce movement, either external or internal, some force or exertion (not necessarily voluntary) is used, and all force involves wear and tear. This wear and tear takes place in the flesh and blood, the fat and bones, and other materials of which the body is composed. If these used-up materials are not replaced, the body will wear away, and the animal become exhausted and die. All living human bodies are warm.1 If the warmth 1 The temperature of the human body is about 98° Fahr. , and in healthy persons is nearly uniform both in hot and in cold weather. Thermometers, instruments formeasuringheat, have been constructed by various persons : the one made by Fahrenheit is in most general use. Freezing point is 320 (° means degrees); temperate, 55°; summer heat, 76°; blood heat, 98°; boiling point (water), 213°. INTRODUCTION. is not kept up they die. In keeping up this warmth something is used up, and this must be replaced. Food replaces the materials used up by the movement of our bodies, keeps up warmth, and gives power of movement, or, as it is more correctly called, force. Food cannot, however, accomplish these objects in its natural state. It must be reduced into a lluid form so as to be able to pass through very small channels, and to be carried along in the blood. After it enters the bloodvessels it must mix with air,1 drawn in through the lungs and skin, and through the changes effected by the air and by various other organs of the body, the food is gradually made fit to replace all wasted and worn-out materials. I he wholesomeness of food depends on three conditions : — 1. On the selection of the right materials, whether animal or vegetable, and on their use in proper proportions. 2. On cooking the materials in such a manner as to make them digestible, — that is, capable of being readily turned into material fit for replacing the waste of the body already spoken of. 3. On adapting the use of food to the different circumstances of age, employment, climate, and state of health. 1 That part of air called oxygen. CHAPTER I. Before learning the principles of Cookery, it is important to know something about the composition of the different kinds of food, in order to choose those that are best fitted to keep the body in health and vigour. For this purpose let us consider one or two of our most important foods. Milk is the most perfect human food that we have; infants live on it alone. We find that if milk stands for a little, the cream or fatty part separates and rises to the top, leaving the skim milk below. The cream is the principal part which gives warmth, but it does not repair the used-up materials of the body. The skim milk does this. Skim milk can be separated into curd and whey. Curd is, strictly speaking, the fleshforming part : whey supplies water, sugar, and mineral substances.

The school cookery book