THE HEART.
[Illustration: T]HE heart is in the chest, the upper part of the strong
box which the ribs, spine, shoulder-blades, and collar-bones make for
each of us.
It is made of very thick, strong muscles, as you can see by looking at a
beef's heart, which is much like a man's, but larger.
HOW THE HEART WORKS.
Probably some of you have seen a fire-engine throwing a stream of water
through a hose upon a burning building.
As the engine forces the water through the hose, so the heart, by the
working of its strong muscles, pumps the blood through tubes, shaped
like hose, which lead by thousands of little branches all through the
body. These tubes are called arteries (aer't[)e]r iz).
Those tubes which bring the blood back again to the heart, are called
veins (v[=a]nz). You can see some of the smaller veins in your wrist.
If you press your finger upon an artery in your wrist, you can feel the
steady beating of the pulse. This tells just how fast the heart is
pumping and the blood flowing.
The doctor feels your pulse when you are sick, to find out whether the
heart is working too fast, or too slowly, or just right.
Some way is needed to send the gray fluid that is made from the food we
eat and drink, to every part of the body.
To send the food with the blood is a sure way of making it reach every
part.
So, when the stomach has prepared the food, the blood takes it up and
carries it to every part of the body. It then leaves with each part,
just what it needs.
THE BLOOD AND THE BRAIN.
As the brain has so much work to attend to, it must have very pure, good
blood sent to it, to keep it strong. Good blood is made from good food.
It can not be good if it has been poisoned with alcohol or tobacco.
We must also remember that the brain needs a great deal of blood. If we
take alcohol into our blood, much of it goes to the brain. There it
affects the nerves, and makes a man lose control over his actions.
EXERCISE.
When you run, you can feel your heart beating. It gets an instant of
rest between the beats.
Good exercise in the fresh air makes the heart work well and warms the
body better than a fire could do.
DOES ALCOHOL DO ANY HARM TO THE HEART?
Your heart is made of muscle. You know what harm alcohol does to the
muscles.
Could a fatty heart work as well as a muscular heart? No more than a
fatty arm could do the work of a muscular arm. Besides, alcohol makes
the heart beat too fast, and so it gets too tired.
REVIEW QUESTIONS.
1. Where is the heart placed?
2. Of what is it made?
3. What work does it do?
4. What are arteries and veins?
5. What does the pulse tell us?
6. How does the food we eat reach all parts of the
body?
7. How does alcohol in the blood affect the brain?
8. When does the heart rest?
9. How does exercise in the fresh air help the
heart?
10. What harm does alcohol do to the heart?