The Hartford republican., 1913-10-24
MYSTERY OF SIGHT
Most Wonderful and InexplicabIe
of All Our Senses.
LIMITS OF THE HUMAN VISION.
There Are CoIors All About Us That
the Eye Cannot See, as We Cannot
Distinguish Beyond the Extremes Of
the Spectrum Red and Violet.

tne EYE Canhot see, as we Ssnnot
Distinguish Beyond the Extremes Of
the Spectrum Red and Violet.
No two persons see precisely alike
any more than any two persons hear
precisely the same. The differences
In these perceptions are due to the
wide disparities not only in the organs
Of vision and hearing. but also to the
differences in mental makeup of the
individuals.
There are more unsolved problems as
to sight than any other sense. Ii is
the most wonderful and at the same
time the most inexplicable sense that
we possess. Every school child is
taught that we see because rays of
light reach the retina Of the eye after
passing through the transparent cor
nea. that curved surface which Is in
direct contact with the external mir.
the aqueous or watery humor. ana the
crystalline and vitreous humors.
The eye is thus made up of .hree
separate lenses. through which the
light passes before reaching the retina.
When observed from outside IL is plain
that all the images appear to be re-
versed In the eye. We see everything
upside down. but I'm some way this
reversal is corrected. so that things ap-
pear to Us as they should. though this
simple point has not yet been explain
ed by the most advanced science.
But the eye sees not only images and
light: il also distinguishes color. And
here is one Of the greatest problems
with which the eye has TO deal. The
white light Of a ray Of sunshine is
divided by prism into all Of the
colork from red to violet, and it is one
q The greatest triumphs Of modern
optics to have proved that what we ,
call .solor is nothing but the speed
With which some parts of the ray o;
sunshine strike upon the retina.
The eye can perceive waves striking
II as low as red and as high as violet. !
but there are many rays both above
and below the red and violet, the ex-
tremes Of the spectrum. as tbsy are ,
called The human eye cannot per
cejye tbese because the lengths Of the |
waves or the frequency with which
they strike upon the retina are too
great or too small for the human or
gan. Yet they are most important, ex-
ercising a great influence upon human
beings.
The ultra violet rays are known now !
BY their chemical action and are term
ed chemical rays. while the infra red
rays are heat rays and are known as
such. So II Is evident that there is
much that the eye does not or cannot |
see. even with all the mechan anicsl aids
which have been provided in telescope.
etc.
What really carries the message Of
vision to the brain center of vision.
which Is at the back of the head, Is
the optic nerve, and the fact that if
you have a pain in the back Of the
head it is probably due to eye strain is
admitted by all physicians. II you feel
that strain and headache located at the
occiput the first thing to do is to con-
suit an oculist and get the glasses
which will correct the error of vision
Your eyes may be wfong in any num-
ber OF ways. Either there may be de-
feet In some one Of the lenses or the
nerve may have become weakened or
The muscles OF accommodation by
which the eve Is focused may he
wrong. The last is probably the com
aonest OF troubles and may be easily
II promptly taken in hand by
IN expert.
Cross eyes are only defects OF mus
'ular control. and the latest earches
pOint Ia the necessity for correcting
his defect as promptly ms possible
Many parents make the fatal mistake
" not calling In the specialist even
when they notice that an infar,
crosses the eyes" Rnt II Is in the
arly stages that this trouble may he
'est corrected: otherwise the muscles
)ecome fixed In their error and the de
'ect is permanent
1t Is never too early to put glasses
lfson the child who requires them. II is
'ffen too late to save the child from
'ermanent injury of the most beantj.
nj. most expressive aud most usefri
'rgan.-New York World.