The Indianapolis journal. [volume] (Indianapolis [Ind.]) 1867-1904, 1895-05-29
EYES OF ANIMALS.
Curious Facts Abou Beasts, Birds, In
sects and Fish.
Providence Journal.

providence Journal
Human beings have six muscles to each
Il on either side, but horses, COWS, sheep
and other quadrupeds, w;.tch habitually
of food. have a muscle by which the eye
balls are suspended and supported, and
when we do not need. This Is a wonderful
adaptation TO the circumstances in which
the creature is placed. For example, the
eyes Of amphibious animals partly agree
with those of the fish and the quadruped.
The cat and the tiger. which prowl by
night, have a peculiar power or expanding
the pupil. The eyes OF fish have no ap-
paratus TO moisten them, and it would be
obviously unnecessary. The eye is adapted
TO the properties of light. so that it re-
on the retina. Our best and most perfect
glasses are 10y no means equal TO the
number of eyes; they can see on every side
without any movement of the organs of
vision. Fish have a crystal lens. almost
fraction of light in the element in which
they live. and though they have no eye
los. their cornea is horny. TO defend their
sight. The mole has two very small eyes,
hid under his velvet coat; these are ad-
mirably suited 10 his mode of living,
Of the faculties of animals to their mode
of life strikingly displays the wisdom of
Spiders have four, six or even eight eyes.
They are transparent like so many gems.
The lizard called the chameleon can move
one eye while the other is still He can NIX
one on the sky and the other on the
ground. He can glance at all that is behind
and before him at once. Lord Brougham
remarks of the eyes of birds that they
require TO have them sometimes as nat
as possible for protection and at other
times as round as possible that they may
see the flies and other insects when they
chase through the air, and which they
pursue with the most unerrinS certainty.
This could only be accomplished by CIV
tne them a power OF suddenly hanging the
form of their eyes. Accordingly, there Is
a set Of hard scales placed on the outer
coat of their eyes round the place where
the light centers, and over these scales are
drawn the muscles or fibres by which mo-
ton IS communicated, so that, by acting
with these muscles, the bird can press the
scales and squeeze the natural magniher or
the eye into a round shape when ii wishes
10 follow an insect through the air and can
relax the scales in order to fiatten the eye
Or move safely through leaves or twigs.'
This power of altering the shape or the
f sye izk P5 5is 5seIee by 9PibEs dS e OF prey Tes the TN a sn neTy
est objects close to them, and can yet dis
Germ larger bodies at a vast distance, as a
FISH afOat upon the water. The eyehd is
designed 10 moisten the eye and TO keep
keeping the surface OF the birds eye clean
for wiping. as 1t We're. the glass of the in
strunentEand also for protesting, it while
thickets. without hindering the sight. Birds
are. for these purposes, furnished with a
IS constantly moved very. rapidly over the
eyeball by two muscles placed in the back
OF the eye. One of the muscles ends In a
loop, the other in a string which goes
through the loop and is fixed in the corner
Of the membrane. to pull it backward and
forward. If you wish 10 draw anything
must pull directly in the line between the
thing and the place; but II you wish to
draw IL as quickly as possible and do not
regard the loss of force. you must pull
Obliquely. Tie n string to a stone and pull
II straight toward you; then make a loop
through II. draw one string in each hand
sideways till both are stretched in a straight
line. YOU will see now much Swifter the
stone moves than it did before. Velocity is
the thing required in the birds third eye
lid. and the contrivance is exactly that of a
string and a loop. moved each by a muscle.
as the two strings are by hands in the case
mentioned.