The blood is speedily exhausted of its richness, because it gives up its several ingredients to the different parts of the living frame to confer warmth, repair, and active strength upon them. The warmth is procured by burning the fat; you will easily understand that; you know that an oil lamp gets very hot whilst its flame is kept up. The repair is effected by the plastering of new matter out of the blood, upon all the different structures as they wear away. Each structure chooses for itself out of the blood what it wants, and arranges what it takes in due order. But you would now like to know how active strength is supplied by the blood. It will not be possible just now to tell you concerning this, all which might be, and indeed ought to be told, because we have other and more practical things to bend our attention to. But this much you will easily comprehend. The power comes out of that very change of substance, which we call wear. The “wear” is actually the turning of the substance into power. Upon another occasion this may be made more plain.
The blood supplies what every part of the living body requires, and of course itself loses what it gives out. But the exhausted blood is in its turn renewed and refreshed by occasional supplies of food. Here then we at last arrive at the pith of the subject we are speaking of. The food supplies the blood, and the blood supplies the body. Therefore efficient and good food must have in it all the several principles required by the body—flesh, fuel, and mineral. No kind of food is sufficient to maintain vigorous life and health, which does not contain a due amount of every one of these.
When the young animal comes first into the world, its powers of digestion are weak, and it is fed for some time entirely upon a food already digested for it by the parent. This parent-prepared food of the young animal, which is called milk, of course contains within itself all the several matters which have been spoken of above, as necessary for the supply of the body. Thus when the dairy-maid curdles milk with rennet, and draws off the whey, afterwards pressing and drying the curdled part, the curd at length comes out of the press as cheese. That is the flesh-substance which was contained in the milk. When the dairy-maid turns and twists cream about in the churn, until butter collects in the midst of it—that butter is the fuel-substance, or fat, which was contained in the milk. The whey which is taken off from the cheese, or butter, is principally water; but if this water were steamed away by heat, there would remain behind a small quantity of fixed ash, which could not escape. This is the mineral-substance. Here then we have what we may term a specimen of Nature’s pattern-food. The relative proportion in which the several food-principles are contained in milk, becomes most excellent guide to the way in which they should be used in the more artificial feeding of later life. Take then as
A RECEIPT FOR PATTERN-FOOD,
the following, which expresses the relative quantities of cheese, butter, and ash, in milk:
- One ounce of Flesh-substance,
- Two ounces of Fuel-substance, and
- Ninety grains of Mineral-substance,
- To twenty-two ounces of Water.
The most extensively and generally used of all the articles of human diet is bread. It has been fittingly called “the staff of life.” Now it is a curious and remarkable fact that bread contains in itself just the same principles as milk; but it is of course drier, and has proportionally more fuel and less flesh-making substance. The flour, from which it is made, is composed of a stiff, sticky paste, and a fine white powder, well mixed up together. The paste is flesh-substance; it is nearly the same thing, indeed, as the flesh of the body, in all excepting arrangement. The powder is starch: just such as is used in the work of the laundry. Now starch is merely fat in its first stage of preparation.
When bread is well made, the rising of the dough marks the change of the store-starch into sugar and gum through fermentation. This is really a beginning of the work of digestion, and, in so far, a lightening of the task the stomach will have to perform. It is very important, however, that this change shall be carried to a proper point, and then stopped. Bread should be neither too heavy nor too light. If the former, it will not be easy enough of digestion; if the latter, some portion of the virtue will have been unnecessarily wasted. Bread contains a great deal of water, and so to a certain extent is both food and drink.
Brown bread is more rich in flesh-making substance, bulk for bulk, than fine wheaten bread, because the outer husk of the grain, which constitutes the bran, itself contains a large quantity of that material. When the dough is formed from whole meal, instead of fine flour, the cost of the bread is considerably diminished, at the same time that its bulk and weight are, even in a greater degree, increased.
Rye bread is not so pleasant in flavor as wheaten bread, but it is about equal to it in nourishment, and can be kept for months without being spoiled, which wheaten bread can not. Oatmeal can not be fermented like wheaten meal, but it is nearly as rich again in flesh-making substance. It is its very richness in this gluey material, which renders it incapable of being made into bread. Scotch men and women consume a great quantity of oatmeal as porridge and unfermented cake, and get both very fat and strong upon their food. This article of diet has, indeed, the recommendation of being very appropriate for young people, who are growing rapidly, and is fortunately, at the same time, comparatively cheap.