You remember a certain door-keeper, or porter, of whom we have already
spoken a good deal, who resides in the mouth--the sense of taste, I
mean?
Well, it is a porter's business to sweep out the entrance to a house,
and you may always recognize him in the courtyard by his broom.
And accordingly our porter too has a broom specially placed at his
service, namely, the tongue; and an unrivalled broom it is--for it is
self-acting, never wears out, and makes no dust--qualities we cannot
succeed in obtaining in any brooms of our own manufacture.
When the time has come for the pounded mouthful (described in the last
chapter) to travel forward (the teeth having properly prepared it),
the broom begins its work; scouring all along the gums, twisting and
turning right and left, backwards and forwards, up and down; picking
up the least grains of the pulp which have been manufactured in the
mouth; and as the heap increases, it makes itself into a shovel--another
accomplishment one would scarcely have expected it to possess. What
it gathers together thus, rolls by degrees on its surface into a ball,
which at last finds itself fixed between the palate and the tongue in
such a manner that it cannot escape; at which moment the tongue presses
its tip against the upper front teeth, forms of itself an inclined
plane, and--but stop! we are getting on too fast.
At the back of the mouth, (which is the antechamber, as we said before,)
is a sort of lobby, separated from the mouth by a little fleshy
tongue_let_, suspended to the palate, exactly like those tapestry
curtains which are sometimes hung between two rooms, under which one
is enabled to pass, by just lifting them up.
If this lobby led only from the mouth to the stomach, the act of
swallowing would be the simplest thing in the world; the tongue would
be raised, the pounded ball would glide on, would pass under the
curtain, and then good-bye to it. Unfortunately, however, the architect
of the house seems to have economized his construction-apparatus here.
The lobby serves two purposes; it is the passage from the mouth to the
stomach, as well as from the nose to the lungs.
The air we breathe has its two separate doors there--one opening
towards the nose, the other towards the lungs; through neither of which
is any sort of food allowed to pass. But, as you may imagine, the food
itself knows nothing of such spiteful restraints, and it is a matter
of perfect indifference to it through which of the doors it passes.
Not unlike a good many children who, though they are reasonable
creatures, will push their way into places where they have been
forbidden to go; and who can expect a pulpy food-ball to be more
reasonable than a child? It was necessary, therefore, so to arrange
matters that there should be no choice on the subject; that when the
food-ball got into the lobby it should find no door open but its own,
namely, that which led to the stomach. And that is exactly what is
done.
You have not, perhaps, remarked that in the act of swallowing, something
rises and contracts itself at the same moment in your throat, producing
a kind of internal convulsion which jerks whatever is inside. People
do not think about it when they are eating, because it is an involuntary
action, and their attention is otherwise engaged.
But try to swallow when there is nothing in your mouth, and you will
perceive what I mean at once.
Now, imagine our lobby at the back of the throat as a small closet,
with a doorway in its wall, half-way up, the doorway being closed by
a curtain. In the ceiling is a hole, which leads to the nose; in the
floor two large tubes open out; the front one leading to the lungs,
the one behind, to the stomach.
Now swallow, and I will tell you what happens. The curtain rises up
and clings to the ceiling, and thus the passage to the nose is stopped
up. The lung-tube rises along the wall, and hides itself under the
door, contracting itself, and making itself quite small, as if it
wished to leave plenty of room for the mouthful of food which is about
to pass over it; and, for still greater security, at the very moment
it rises, it pushes against a small trap-door which shuts up its mouth.
No other road remains, therefore, but through the tube which leads to
the stomach; the pulpy mouthful drops straight therein, without risk
of mistake, and when it is once there, everything readjusts itself as
before.
These are very ingenious contrivances, and I will venture to say that
if we would but study the wonders of the marvellous and varied machinery
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
it is called; otherwise, breath would all at once fail you, and you
would be obliged to stop short in the middle of a sentence and wait
like a simpleton till you had refilled the lungs with air by breathing.
It was for this purpose, also, and not for mere economy's sake, as you
may have thought, that the little cross-road of four doors has been
placed at the back of the mouth, enabling it to communicate at pleasure
with either the lungs or the stomach. It is a dangerous passage for
food-parcels making their way to the stomach; but if you could
substitute for it, as it may have occurred to you to do lately, a
simple tube going directly to the stomach,--behold! you would find
yourself dumb;--a serious misfortune, eh? for a little girl! But come,
I am quizzing too much, so console yourself. I know many grown-up
people who would be at least as sorry as yourself.
To return to our subject. We have said that, in order to guard against
accidents, the lung-tube is closed at the moment we are about to
swallow. But if by any unlucky chance the air is coming up from the
lungs at the same moment, it must have a free passage. Its tube cannot
help returning to its place; the little trap-door which shuts up the
opening opens whether or no, and then adieu to all the precautions of
good Mother Nature! The mouthful when it drops, falls outside of its
proper tube--that is to say, into the other, which is exactly in front
of it, and we find that we have _swallowed the wrong way_.
You know what happens in such a case. You cough and cough till you are
torn to pieces, till you grow scarlet, or even blue in the face; till
you lose your breath; till your body trembles; till your eyes start
out of their sockets. Let who will be there, there is no resource but
to hide your face in your handkerchief. The tube, which was only made
for the passage of air, on finding an intruder forcing an entrance,
does its utmost to drive it back through the door. Then the lungs,
which would be destroyed by its getting to them, come to the assistance
of the faithful servant who is struggling for their protection: they
agitate themselves violently, and send forth gusts of air which drive
all before them. Thence arises the cough, and by this means at last
the enemy is thrust out of the mouth, like dust before the wind. And
it is only when the passages are cleared that the storm subsides. But
the commotion is no laughing matter, I assure you; for if one had
swallowed a little _too far_ the wrong way, or if the substance
swallowed had been too heavy for the air-tube, aided by the lungs, to
eject within a certain time, death would have ensued: instances of
which are by no means unknown. Nature does nothing in vain; this is
no case of a man frightened by a mouse. When you find your whole being
concentrating its efforts to one point, and betraying such distress,
at an accident apparently so trifling, you may be sure there is danger,
and real danger too; and if you doubt it, that makes no
difference--happily for you.
Now you have learned why little girls should not attempt to talk and
swallow at the same time, and, I may add, still less laugh; for
laughingis a kind of somersault, performed by the lungs, and is always
accompanied by the ejectment of a great deal more breath than is
necessary in speaking, so that the jerks it occasions derange still
more the wise provisions made to protect life whenever we swallow
anything, and therefore we are more apt to swallow the wrong way while
laughing than while speaking.
Need I say that we ought equally to guard against making others laugh
or talk; or exciting, or frightening them, while they are swallowing;
in short, avoid doing anything to create a sudden shock which might
suddenly force the air out of their lungs, and cause them in the same
manner to swallow the wrong way? Politeness requires this from us, and
what I have now said will fix the lesson still more strongly on your
mind. What would become of you if you were to see a person die in your
presence in consequence of some foolish joke, however apparently
innocent?
Not to conclude with so painful a picture, I will, before we part,
give you the right names of the _curtain_, the _lobby_ or _closet_, and
the _tubes_ of which we have been speaking.
The curtain is called the _Soft Palate_.
The lobby, the _Pharynx_.
The tube which leads to the stomach, the _Aesophagus_.
The tube leading to the lungs, the _Larynx_.
The opening of this tube is the _Glottis_, and the little trap-door
which closes it when one swallows, is the _Epiglottis_.
You must excuse my attempting to explain the meanings of all these
names; it would take me too long to do so. After all, the mere names
are nothing. If I have succeeded in making you understand how all the
different parts act, you may call them what you like.
Here we will rest. We are now on our way to where we shall see the
large apartments, and be introduced to the master, that head of the
house, whom no one can approach without so many ceremonies.