When I said formerly that our dear and wonderful steward the blood,
was everywhere at once, you little suspected the prodigies involved
in that _everywhere_. But you will have a glimpse of them now, when I
tell you it is at the extremities of the _capillary arteries_ that he
carries on his distribution of goods, and accomplishes a mysterious act
of nutrition; a wonder much greater even than that of which we have just
spoken. Here, indeed, the question is no longer mechanical divisions,
whose delicacy, surprising as it may be, is yet within our powers of
comprehension. What is more surprising still, what moreover we cannot
comprehend at all, is the delicate sensitiveness of tact--I would almost
say of instinct--with which each one of the million millions of tiny
atoms of which our body is composed, draws out of the blood--the common
food of all--exactly that aliment which is necessary to it, leaving the
rest to his neighbor, and this without ever making a mistake.
You have never thought about this; for children go on living at their
ease, as if it was the simplest thing in the world to do; never
suspecting even that their life is a continued miracle, and never, of
course, therefore, feeling bound to be grateful to the Author of that
miracle. And alas! how many hundreds of people live and die children
in that respect.
But what would happen, I should like to know, if the eye took to seizing
upon the food of the nail, if the hairs stopped on the way what was
intended for the muscles, if the tongue absorbed what ought to go to
the teeth, and the teeth what ought to go to the tongue! Yet what
prevents their doing so? Can you tell me? They all drink alike out of
the same cup. The same blood goes to furnish them all. The substances
that it brings to the eye are the same as those which it brings to the
nail; and nevertheless the eye takes from it that which makes an eye,
and the nail that which makes a nail.
How is this done, do you think? that is the question.
When the doctors reply to this, that each organ has its peculiar
sensibility, which makes it recognize and imbibe from the blood one
particular substance and no other, they are strangely mistaken if they
flatter themselves that they have really answered anything. They have
done nothing but reproduce the question in other words, for it is
precisely that sensibility which requires explanation, and to tell us
that it exists, does not explain much, you must own. If you were to
ask why you had got a headache, and some one were to reply that it was
because your head ached, you would not be much the wiser I fancy.
Each of our organs, then, may be considered as a distinct being, having
its separate life, and its particular likings. These organs behave
towards the blood like men who recognize some friend in a crowd, and
proceed to seize him by the arm; and when I told you just now that
they never made a mistake, I spoke of their regular course of action
in ordinary circumstances. Like men, they also make mistakes sometimes,
in certain cases; and take one substance for another, or do not
recognize the one they are in need of; an unanswerable proof that at
other times they exercise a sort of discernment, and do not act by a
sort of fatality, as one might be tempted to believe. Look at the
bones, for instance. They are composed of _gelatine_ (which cooks
serve up under the name of meat-jelly, but which would be more properly
called bone-jelly), and of phosphate of lime, a kind of stone of which
we have spoken before, if I remember rightly, and from which they get
all their solidity. Originally, the substance of the bone is entirely
gelatinous, and the phosphate of lime deposits itself therein by
degrees, as time goes on, and always in greater abundance as we advance
in age.
Properly the bones borrow only gelatine and phosphate of lime from the
blood. But when they come to be broken, their texture or _tissue_
inflames in the fractured place; and then it changes its tastes, if
I may so express myself; and, lo and behold, extracts from the blood
that which forms certain little fleshy shoots, which unite together
from the two sides of the fracture, and so mend the broken bone. Here is
one exception to the rule.
Again, in certain diseases, the bones suddenly quarrel with the
phosphate of lime; they will not hear of it any longer, they will not
accept a fresh supply; and as the old wears out by degrees, by reason
of the continual destruction of which I spoke the other day, the bones
become more and more enfeebled, and soon can no longer support the
body. A second exception this.
Finally, when old age comes on, the bones end by being so much
encumbered with phosphate of lime, that they have no room to admit the
fresh supply which keeps coming to them in the blood. What becomes of
it then? It goes to seek its fortune elsewhere; and there are charitable
souls, who forgetting their instinctive antipathies, consent to give
it hospitality, though much to the prejudice of the poor old man
himself, who is no longer served so well as formerly, by the incautious
servants who have allowed themselves to be thus fatally beguiled; but
no one consults him. It is the arteries especially, and sometimes
the muscles, which take this great liberty, and it is not unusual among
old people to meet with these fairly _ossified_--that is to say,
changed into bone, thanks to the phosphate of lime with which they
have consented to burden themselves. This is a third exception, and
I will spare you any others.
What may we infer from all this, my dear child? Well, two things.
First, that we know nothing at all about the whole affair; a fact which
at once places us on a footing with the most learned philosophers in
the world. Secondly, that our body is a perpetual miracle; a miracle
which eats and drinks and walks, and which we must not look down upon
for so doing: for God dwells therein. I should have to come back to
this at every turn, if I wanted to fathom everything I have to tell
you about. Each tip of hair which you grow, is an incomprehensible
prodigy which would puzzle us for ever, if we did not call to our aid
those eternal laws which have made us what we are, and to which it is
very just our spirits should submit, since we could not exist for one
second were they to cease from making themselves obeyed in our bodies.
Reflect on this, my dear little pupil. Young as you may be, you can
already understand from it, that there is above you something which
demands your respect. The good God, to whom your mother makes you pray
every night, on your knees, with folded hands, is not so far off as
you might perhaps suppose. He is not a being of the fancy, secluded
in the depths of that unknown space which men call Heaven, in order
to give it a name. If His all-powerful hand reaches thus into the
innermost recesses of your body, His voice speaks also in your heart,
and to what it says you must listen.