WE have five
ways of learning about all things around us.
We can see them, touch them, taste them, smell them,
or hear them. Sight, touch, taste, smell, and
hearing, are called the five senses.
You already know something about them,
for you are using them all the time.
In this lesson, you will learn a little
more about seeing and hearing.
THE EYES.
In the middle of your eye is a round,
black spot, called the pupil. This pupil is only
a hole with a muscle around it. When you are in
the light, the muscle draws up, and makes the pupil
small, because you can get all the light you need
through a small opening. When you are in the dark,
the muscle stretches, and opens the pupil wide to let
in more light.
The pupils of the cat’s eyes
are very large in the dark. They want all the
light they can get, to see if there are any mice about.
The pupil of the eye opens into a
little, round room where the nerve of sight is.
This is a safe place for this delicate nerve, which
can not bear too much light. It carries to the
brain an account of every thing we see.
We might say the eye is taking pictures
for us all day long, and that the nerve of sight is
describing these pictures to the brain.
CARE OF THE EYES.
The nerves of sight need great care,
for they are very delicate.
Do not face a bright light when you
are reading or studying. While writing, you should
sit so that the light will come from the left side;
then the shadow of your hand will not fall upon your
work.
One or two true stories may help you
to remember that you must take good care of your eyes.
The nerve of sight can not bear too
bright a light. It asks to have the pupil made
small, and even the eyelid curtains put down, when
the light is too strong.
Once, there was a boy who said boastfully
to his playmates: “Let us see which of
us can look straight at the sun for the longest time.”
Then they foolishly began to look
at the sun. The delicate nerves of sight felt
a sharp pain, and begged to have the pupils made as
small as possible and the eyelid curtains put down.
But the foolish boys said “No.”
They were trying to see which would bear it the longest.
Great harm was done to the brains as well as eyes of
both these boys. The one who looked longest at
the sun died in consequence of his foolish act.
The second story is about a little
boy who tried to turn his eyes to imitate a schoolmate
who was cross-eyed. He turned them; but he could
not turn them back again. Although he is now a
gentleman more than fifty years old and has had much
painful work done upon his eyes, the doctors have
never been able to set them quite right.
You see from the first story, that
you must be careful not to give your eyes too much
light. But you must also be sure to give them
light enough.
When one tries to read in the twilight,
the little nerve of sight says: “Give me
more light; I am hurt, by trying to see in the dark.”
If you should kill these delicate
nerves, no others would ever grow in place of them,
and you would never be able to see again.
THE EARS.
What you call your ears are only pieces
of gristle, so curved as to catch the sounds and pass
them along to the true ears. These are deeper
in the head, where the nerve of hearing is waiting
to send an account of each sound to the brain.
CARE OF THE EARS.
The ear nerve is in less danger than
that of the eye. Careless children sometimes
put pins into their ears and so break the “drum.”
That is a very bad thing to do. Use only a soft
towel in washing your ears. You should never
put any thing hard or sharp into them.
I must tell you a short ear story,
about my father, when he was a small boy.
One day, when playing on the floor,
he laid his ear to the crack of the door, to feel
the wind blow into it. He was so young that he
did not know it was wrong; but the next day he had
the earache severely. Although he lived to be
an old man, he often had the earache. He thought
it began from the time when the wind blew into his
ear from under that door.
ALCOHOL AND THE SENSES.
All this fine work of touching, tasting,
seeing, smelling, and hearing, is nerve work.
The man who is in the habit of using
alcoholic drinks can not touch, taste, see, smell,
or hear so well as he ought. His hands tremble,
his speech is sometimes thick, and often he can not
walk straight. Sometimes, he thinks he sees things
when he does not, because his poor nerves are so confused
by alcohol that they can not do their work.
Answer now for your taste, smell,
and touch, and also for your sight and hearing; should
their beautiful work be spoiled by alcohol?
REVIEW QUESTIONS.
1.
Name the five senses.
2.
What is the pupil of the eye?
3.
How is it made larger or smaller?
4.
Why does it change in size?
5.
What can a cat’s eyes do?
6.
Where is the nerve of the eye?
7.
What work does it do?
8.
Why must one be careful of his eyes?
9.
Where should the light be for reading or
studying?
10.
Tell the story of the boys who looked at the
sun.
11.
Tell the story of the boy who made himself
cross-eyed.
12.
Why should you not read in the twilight?
13.
What would be the result, if you should kill
the
nerves of sight?
14.
Where are the true ears?
15.
How may the nerves of hearing be injured?
16.
Tell the story of the boy who injured his ear.
17.
How is the work of the senses affected by
drinking
liquor?