EYES. 
By W. E. Watt. 
Why was the sight 
To such a tender ball as th' eye confined, 
So obvious and so easy to be quenched, 
And not, as feeling, through all parts diffused; 
That she might look at will through every pore ? — Mii/Ton. 
"But bein' only eyes, you see, my wision's limited." — Sam Wei^er. 
(5 I HE REASON we know any- 
4 I thing at all is that various 
I forms of vibration are capa- 
ble of affecting our organs 
of sense. These agitate the brain, the 
mind perceives, and from perception 
arise the higher forms of thought. 
Perhaps the most important of the 
senses is sight. It ranges in power 
from the mere ability to perceive the 
difference between light and darkness 
up to a marvelous means of knowing 
the nature of objects of various forms 
and sizes, at both near and remote 
range. 
One the simplest forms of eyes is 
found in the Sea-anemone. It has a 
colored mass of pigment cells and 
refractive bodies that break up the 
light which falls upon them, and 
it is able to know day and night. An 
examination of this simple organ leads 
one to think the scientist not far wrong 
who claimed that the eye is a develop- 
ment from what was was once merely 
a particular sore spot that was sensitive 
to the action of light. The protophyte, 
Euglena varidis, has what seems to be 
the least complicated of all sense 
organs in the transparent spot in the 
front of its body. 
We know that rays of light have 
power to alter the color of certain 
substances. The retina of the eye is 
changed in color by exposure to con- 
tinued rays of light. Frogs in whose 
eyes the color of the retina has 
apparently been all changed by sun- 
shine are still able to take a fly accu- 
rately and to recognize certain colors 
Whether the changes produced by 
light upon the retina are all chemical 
or all physical or partly both remains 
open to discussion. 
An interesting experiment was per- 
formed by Professor Tyndall proving 
that heat rays do not affect the eye 
optically. He was operating along 
the line of testing the power of the 
eye to transmit to the sensorium the 
presence of certain forms of radiant 
energy. It is well known that certain 
waves are unnoticed by the eye but 
are registered distinctly by the photo- 
graphic plate, and he first showed 
beyond doubt that heat waves as such 
have no effect upon the retina. By 
separating the light and heat rays from 
an electric lantern and focusing the 
latter, he brought their combined 
energy to play where his own eye 
could be placed directly in contact 
with them, first protecting the exterior 
of his eye from the heat rays. There 
was no sensation whatever as a result, 
but when, directly afterward, he 
placed a sheet of platinum at the 
convergence of the dark rays it quickly 
became red hot with the energy which 
his eye was unable to recognize. 
The eye is a camera obscura with a 
very imperfect lens and a receiving 
plate irregularly sensitized; but it has 
marvelous powers of quick adjust- 
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