The Bellefontaine Republican. [volume] (Bellefontaine, Logan County, Ohio) 1855-1905, 1903-09-01
NUMBER 20.
YOU HAVE SIX EARS.
THE ORGANS OF HEARING ARE A
WONDERFUL SET OF MACHINES.

Anvfls, Two stirrups, Six Canals,
Two Snail Shells, Six Drums and
Several other Curious Utensils
The hearing apparatus is far more
wonderful than most people have the
slightest idea Of. 1t is a marvellous
collection of instruments for receiving,
magnifying and recording sounds or
vibrations, as the learned term them
What you do when you speak to q
friend 10 to throw the air into vibra-
ton. Your vocal organs strike the air,
and the impulses thus caused reach the
trumpet shaped bits Of flesh and gristle
you call ears. You have altogether six
ears.
The naps which are stuck ON to each
side Of the head are the outer ears Be
sides these there are the middle ears
and the inner ears, all of which lie In
cavities In the bones of the head All
that the flaps do is to collect and CON-
centrate the vibrating currents Of air,
20 that they may strike the ear drums
These latter are really the middle
ears. The outer ear narrows as il en-
tiers the head and ends in a ring. A
membrane Is stretched over this ring.
much in the same way as piece OF
parchment is stretched over the head
Of a drum.
The gar drum il q true drum. for II
can be frightened and slackened by
means Of levers made for that purpose.
The Tightening and slackening are done
quite automatically to suit the various
sounds.
This is how it is frightened: In the
middle ear are four tiny bones, the
most peculiar looking bones imagina-
BILE. The biggest is little odd shaped
bone called the mallet. 1t looks like q
| lilliputian version of a Holsters claw.
| Minute muscles are attached to il, SO
| that ii may act as a lever to increase
or diminish the tension Of the drum
skin One muscle reiaxes the men,
brane, another pulls it taut
The four bones form a chain to con-
| meet the drum skin of the outer ear with
the drum skin of the inner and 50 to
conduct the sound. The next bone to
| the mallet is the anvil, then come the
spherical bone and the stirrup. which
looks exactly like its namesake, but 1t
is by far the most important Of the
four By means of this alone one can
hear, in q fashion, even il all the others
be gone.
bony, gristly tube joins the ear
drum with the back of the mouth at
the side of the soft palate. Hence the
four bones are always in a bath of air,
L - - T. 80
this that people who are somewhat
deaf are able to hear better when they
listen with their mouths open.
Now we come to the inmost ear.
which is made up of three parts The
first one is called the vestibule, or hall,
and II has a drumhead to which the
chain of little bones is attached
The hall leads to the other parts,
both Of which consist of tortuous tubes
part Ii made of three semicircular
canals. The other is shaped exactly az
snail's shell All these make up a
peculiar labyrinth, and all are COM
pletely filed with a curious fluid. Their
walls are lined with the soft, pulpy
nerves of hearing which communicate
with the brain Owing to these COM
plex and winding cavities. great ex-
tent of nerves is exposed for the recep-
tion Of sound
Now let us see what happens when
somebody says "Hearr' to you.
The air In thrown into vibrations,
which spread out and out until they
touch the side of your head. There
the fieshy flap ON one side collects and
magnifies the vibrations.
Down the ear funnel they pass until
they reach the membrane of the drum
of the ear. They strike on the mem
brane, which adapts itself to them
Then the vibrations are communicated
through the bones in the middle ear
to the membrane covering the entrance
to the labyrinth
II you keep your mouth wide oper
the air vibrations pass direct to the
little bones. The impulses of the all
are not interrupted by first having tc
strike the membrane of the drum; thai
, is all the difference.
People could easily converse witt
their ears sealed up. If the two
speakers each held an end of the same
piece of hard wood against their teetf
even the faintest whisper could be un
derstood.
You will see from this that what ar
, commonly called the ears are not es
, sentially necessary to hearing, afte
, all.
Well, however the vibrations are re
eeived, they finally strike against tn
membrane covering the entrance to th'
hall of the labyrinth. Thence the.
make the fluid which fills the labyrinth
. vibrate. These vibrations act on tn
! fibers of the auditory nerve, the fiber
which coat the inner ear. Along thi
q nerve the impressions are communicai
. ed to the brain. In this manner tn
4 sensation of sound is produced. an
you know that somebody said Hear.
to you