That is true. Neither then, nor since then, have you eaten those things, and what is more, I hope you never will. And yet both must have got into your mouth, for without them your teeth could never have grown. How are we to get out of this puzzle?
Suppose now, for a moment, that instead of phosphorus and lime, thelittle workmen in your jaws had asked the blood for sugar to make the teeth with. Fortunately this is only a supposition; otherwise I should be in great fear for the poor teeth: they would not last very long. Suppose, further, that instead of your eating the lump of sugar which was destined to turn into a tooth, your mamma had melted it in a glass of water, and had given it to you to drink; you could not say you had eaten sugar, and yet the sugar would really have got into your stomach, and there would be nothing very wonderful if the stomach had found it out and given it to the blood, and the blood had carried it off to the place where it was wanted. Now, allowing that the lump of sugar was very small, and the glass of water very large, the sugar might have passed without your perceiving it, and yet the tooth would have grown all the same, and without the help of a miracle.
And this is how it was. In the milk which you drank as a baby there were both phosphorus and lime, though in very small quantities. There were many other things besides; everything of course that the blood required for the use of its work-people, because at that time the stomach was only receiving milk, and yet all the work was going on as usual.
And therefore, my dear child, whenever in the course of our studies, you hear me describe such and such a thing as being within us, say quietly to yourself, "that also was in the milk which nourished me when I was a baby."
Of course, the same things are in what you eat now; only now they come in a form more difficult to deal with, and the labor of detaching them from the surrounding ingredients is much greater. The whole business indeed of this famous machine which we are studying consists in unfastening the links which hold things together, and in laying aside what is useful, to be sent to the blood divested of the refuse. The stomach was too feeble in your infancy to have encountered the work it has to do now. It is for this reason that God devised for the benefit of little children that excellent nourishment—milk—which contains, all ready for use, every ingredient the blood wants; and is almost, in fact, blood ready made.
Only think, my child, what you owe to her who gave you this nourishment! It was actually her blood she was giving you; her blood which entered into your veins, and which wrought within you in the wonderful way which I have been describing. Other people gave you sugar-plums, kisses, and toys; but she gave you the teeth which crunched the sugar-plums, the flesh of the rosy cheeks which got the kisses, and of the little hands which handled the toys. If ever you can forget this, you are ungrateful indeed!
Now, beware of going on to ask me how we know that there are so many sorts of things in milk, or I shall end by getting angry. Question after question; why, you might drive me in this way to the end of the world, and we should never reach the point we are aiming at. We have already traveled far away from the teeth, concerning which I wanted to talk to you at this time, but our lesson is nearly over and we have scarcely said a word about them! One cannot learn everything at once. Upon the point in question you must take my word; and as you may believe, I would not run the risk of being contradicted before you, by those who have authority on the subject.
Let it suffice you, for to-day, to have gained some idea of the manner in which the materials which constitute our bodies are manufactured within us. We have got at this by talking of the teeth; to-morrow, it may be the saliva, the next day something else. What I have now told you will be of use all the way through, and I do not regret the time we have given to the subject. If you have understood that well; the time has not been lost.
LETTER V.
THE TEETH (continued.)