You are laughing by this time I know, and I also know the reason why. I have told you the same story twice over. You have not forgotten my wearisome description of gluten, and here I am, saying exactly the same thing of fibrine! You conclude I am dreaming, and have made a mistake!
But no, I am wide awake, I assure you, and mean what I say. And if these details are the same in the two cases, it is for the simple reason that the two bodies are one and the same thing; gluten and fibrine being in reality but one substance, so that were the most skilful professor to see the two together dried, he would be puzzled to say which came from the flour, and which from the blood. I mentioned that our muscles existed in a half-formed state in the blood. Here is something further. The fibres of muscles exist previously in full perfection, in the bread we eat; and when you make little round pills of the crumbs at your side, it is composed of fibres stolen from your muscles which enable the particles to stick together; and I say stolen from your muscles, because they are the gluten which you ought to have eaten. I hope the thought of this may cure you of a foolish habit, which is sometimes far from agreeable to those who sit by you.
This, then, is the first great aliment of nutrition, and you may make yourself perfectly easy about the fate of those who eat bread. If little girls should now and then have to lunch on dry bread, I do not see that they are much to be pitied. There is the starch to keep up their fire, and the gluten for their nourishment, and that is all they require. The porter above is the only one who finds fault. And in these days porters have become more difficult to please than the masters themselves.
Then as to babies who drink nothing but milk, you perhaps wish to know where they get their share of fibrine.
And I am obliged to own there is none in the milk itself; but, I daresay, you know curdled milk or rennet? The same separation into two portions has taken place there which occurs in the blood when drawn from the arm; underneath is a yellowish transparent liquid,—that is the whey; above a white curd of which cheese is made, and which contains a great part of what would have made butter. By carefully clearing the curd from all its buttery particles you obtain a kind of white powder which is the essential principle of cheese, and to which the pretty name of casein is given because caseus is the Latin for cheese. I shall not trouble you now with details about casein; but there is one thing you ought to know. A hundred ounces of casein contain as follows:—
Ounces.
Carbon 63
Hydrogen 7
Oxygen 13
Nitrogen 17
—-
100
Exactly like gluten and fibrine!
Now, then, you can understand that no particular credit is due to the blood for manufacturing muscles out of the cheese of the milk which a little baby sucks. He has much less trouble than the manufacturers at Colmar have in turning their starch into sugar; because in his case the new substance is not only composed of the same materials as the old one, but contains them in exactly the same proportion also.
We have a second aliment of nutrition, you see, and I must warn you that it is not found in milk only. It exists in large quantities in peas, beans, lentils, and kidney-beans, which are actually full of cheese, however strange this may seem to you. It would not surprise you so much, however, if you had been in China and had tasted those delicious little cheeses which are sold in the streets of Canton. They cannot be distinguished from our own. Only the Chinese (from whom we shall learn a great many things when we have beaten them so that they will conclude to be friends with us)—the Chinese, I say, do without milk altogether. They stew down peas into a thin pulp. They curdle this pulp just as we do milk, and in the same way they squeeze the curd well, salt it, and put it into moulds—just as we do—and out comes a cheese at last—a real cheese, composed of real casein! Put it into the hands of a chemist, and ask him the component parts of a hundred grains of it, and he will tell you as follows:—
Ounces.
Carbon 63
Hydrogen 7, etc.