HOW FOOD BECOMES PART OF THE BODY.
[Illustration: H]ERE, at last, is the bill of fare for our dinner:
Roast beef,
Potatoes,
Tomatoes,
Squash,
Bread,
Butter,
Salt,
Water,
Peaches,
Bananas,
Oranges,
Grapes.
What must be done first, with the different kinds of food that are to
make up this dinner?
The meat, vegetables, and bread must be cooked. Cooking prepares them to
be easily worked upon by the mouth and stomach. If they were not cooked,
this work would be very hard. Instead of going on quietly and without
letting us know any thing about it, there would be pains and aches in
the overworked stomach.
The fruit is not cooked by a fire; but we might almost say the sun had
cooked it, for the sun has ripened and sweetened it.
When you are older, some of you may have charge of the cooking in your
homes. You must then remember that food well cooked is worth twice as
much as food poorly cooked.
"A good cook has more to do with the health of the family, than a good
doctor."
THE SALIVA.
Next to the cooking comes the eating.
As soon as we begin to chew our food, a juice in the mouth, called
saliva (sa l[=i]'va), moistens and mixes with it.
Saliva has the wonderful power of turning starch into sugar; and the
starch in our food needs to be turned into sugar, before it can be taken
into the blood.
You can prove for yourselves that saliva can turn starch into sugar.
Chew slowly a piece of dry cracker. The cracker is made mostly of
starch, because wheat is full of starch. At first, the cracker is dry
and tasteless. Soon, however, you find it tastes sweet; the saliva is
changing the starch 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 food every day, until it had grown together again.
So a dinner can both make and mend the different parts of the body.
REVIEW QUESTIONS.
1. What shall we have for dinner?
2. What is the first thing to do to our food?
3. Why do we cook meat and vegetables?
4. Why do not ripe fruits need cooking?
5. What is said about a good cook?
6. What is the first thing to do after taking the
food into your mouth?
7. Why must you chew it?
8. What does the saliva do to the food?
9. How can you prove that saliva turns starch into
sugar?
10. What happens if the food is not chewed and
mixed with the saliva?
11. What comes next to the chewing?
12. What is there wonderful about swallowing?
13. What must you be careful about, when you are
swallowing?
14. What happens to the food after it is
swallowed?
15. How is it changed in the stomach?
16. What carries the food to every part of the
body?
17. How can food mend a bone?