tarch into sugar.
All your food should be eaten slowly and chewed well, so that the saliva
may be able to mix with it. Otherwise, the starch may not be changed;
and if one part of your body neglects its work, another part will have
more than its share to do. That is hardly fair.
If you swallow your food in a hurry and do not let the saliva do its
work, the stomach will have extra work. But it will find it hard to do
more than its own part, and, perhaps, will complain.
It can not speak in words; but will by aching, and that is almost as
plain as words.
SWALLOWING.
Next to the chewing, comes the swallowing. Is there any thing wonderful
about that?
We have two passages leading down our throats. One is to the lungs, for
breathing; the other, to the stomach, for swallowing.
Do you wonder why the food does not sometimes go down the wrong way?
The windpipe leading to the lungs is in front of the other tube. It has
at its top a little trap-door. This opens when we breathe and shuts when
we swallow, so that the food slips over it safely into the passage
behind, which leads to the stomach.
If you try to speak while you have food in your mouth, this little door
has to open, and some bit of food may slip in. The windpipe will not
pass it to the lungs, but tries to force it back. Then we say the food
chokes us. If the windpipe can not succeed in forcing back the food, the
person will die.
HOW THE FOOD IS CARRIED THROUGH THE BODY.
But we will suppose that the food of our dinner has gone safely down
into the stomach. There the stomach works it over, and mixes in gastric
juice, until it is all a gray fluid.
Now it is ready to go into the intestines,--a long, coiled tube which
leads out of the stomach,--from which the prepared food is taken into
the blood.
The blood carries it to the heart. The heart pumps it out with the blood
into the lungs, and then all through the body, to make bone, and muscle,
and skin, and hair, and eyes, and brain.
Besides feeding all these parts, this dinner can help to mend any parts
that may be broken.
Suppose a boy should break one of the bones of his arm, how could it be
mended?
If you should bind together the two parts of a broken stick and leave
them a while, do you think they would grow together?
No, indeed!
But the doctor could carefully bind together the ends of the broken bone
in the boy's arm and leave it for awhile, and the blood would bring it
bone foo
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