which is constantly at work in our behalf within us, we should be much
better employed than in learning things from which no practical good
can be derived. Moreover, we should be ashamed to trust, like the lower
animals, only to our instinct, (which, after all, is much less developed
in us than in them,) for blindly escaping the thousand chances of
destruction that beset a structure so fragile and delicate in its
contrivances as the human body. Besides, it is not only our own
machinery that is entrusted to us, we are liable to be responsible for
that of others, whose development it is our duty to guard and watch;
and how can we do this with a safe conscience, if we are ignorant of
the construction, the action, the laws of all sorts which the great
Artificer has, so to speak, made use of in forming our bodies?

When you, in your turn, are a mother, you dear little rogue, who sit
there opening wide your bright eyes, and not comprehending a word of
what I am saying, you will be glad that you were taught when you were
little, how your own little girl ought to be managed. You will find
a hundred opportunities of making good use, in her behalf, of what you
and I are learning together, and in the meantime there is no reason
why you should not yourself profit by the knowledge you have gained.

I am quite sure, for instance, that in repeating to your child the
simple rule of politeness, with which everybody is acquainted, "_Never
talk when you are eating_," you will be very careful to add, "_and
especially when you are swallowing_," for reasons I am about to detail.

When we want to speak we have to drive the air from the lungs into the
mouth, and our words are sounds produced by this air as it passes
through. This is the reason why I advise you to go on gently, and make
the proper stops in reading aloud: to _take breath_, in fact, as