The Black Hills union and western stock review. [volume] (Rapid City, S.D.) 1904-19??, 1905-07-07
ORGAN OF SIGHT
IN animal WORLD
Wonders Of the Eye as 1t Is
in the Lower
Orders.
TWO EXTREMES OF SIGHT
The Power Of Vision in the Eagle 10
Marvellous, EquaIed Only by the
Woodcock, While Snakes
Can See but Little.

Can See but Little.
New York Evening Post: There was
certainly a time long ago when living
creatures We're not blessed with eyes.
III the creatures now living upon the
earth we may trace a series of eyes
from the highest and most efficient to
the simplest dot Of black pigment. The
eye Of the eagle may stand for the
first and the eye-spot of the amphi-
oxus or the eight-sense germs OF a
jellytish for the other extreme of the
series.
The amphioxus is a little worm or
tish-like creature which most of the
time lives buried in the sand of our
~seashores. He is interesting and i'm
portant out of all proportion to his
size. two inches, for he is one of the
lowliest creatures to be honored with
a backbone, the class mark of all
higher animals. He has no skull and
no brain. but near the front end of the
thin thread of nerve Ghe foreshadow-
ing of our spinal cord) is a tiny black
dot. BY means of this he distinguishes
light from darkness, which is all his
simple life requires. Let us not for
get the position Ct this single, most
primitive of eyes-in the center Of
what would be the brain if the lowly
creature mad one.
The Jellyfish.
The eye of a jellytish is so primi-
tive that we can hardly say whether it
sees or feels. That is. when a floating
jellyfish begins to sink below the sur
face of the water as the shadow of
an advancing ship falls upon it it is
probably affected by the sensation Of
darkness, but perhaps the pressure of
the onrushing wave has something to
do with it.
If we would see an eye which has
actually been evolved from one like
that of amphfoXus let us examine the
head of a lizard. Disregard for a time
his two bright eyes, one on each side
of his head, and look directly down on
the center of the skull between them.
Here we will find an oddly shaped
scale marked with a little depression,
and this is, indeed, what is left of our
CNclopean eye in the tiny sand crea-
ture. Lizards doubtless derive very
little benefit from it, as the nerve lead
inc from It is very small. but in some
of their ancestors it must have been
of great value in detecting the pres
creatures above lizards this third me-
dian eye (called the pineaD is found,
although of 10 use whatever: this
persistence. perhaps. showing Of what
great Importance it once was. In a
chick in the early stages of incubation
s'''' - ~ - i''A' - b'N u
oped. while yet the paired eyes are but
small structures. But suddenly nature
seems to realize that the old regime
has passed-that the little bird will
need other more modern ewes, and the
two side eyes begin to develop with
wonderful ranidity, and soon catch up
with and distance the Cyclops eve.
whose early start ends only in promise.
The Third Eye.
A horse, a bat, a mole. a monkey.
a seal, all have a trace of this third
eye, and when we put a finger on the
soft spot" of the head of a tiny baby
we realize the wonderful import Of 1t
that the Softness is due to a near ap-
proach of this same third eye to the
surface, striving as it has don in so
many lower creatures to push its poor,
imperfect lens to where the light can
act upon 1t. But the old ways have
given place to new, and the child's
blue eyes look out at you and the
world and see all that is necessary for
its life and needs.
We can hardly imagine anything
more terrible than the loss of our eye
sight, and yet there are many creatures
which ave found life more pleasant
In the darkness Of caves and UNDER
ground tunnels or to roam only at
night. when their ayes are useless. and
by lack of use these organs have de-
generated to mere specks. and in some
: cases the skin has grown completely
over them. Thus we find blind fishes
and lizards l. dark caves and blind
ants and moies all but blind in their
dark subterranean homes. Certain
bats, too. have but tiny dots for eyes.
} and depend chiefly upon their acute
hearing and some sense by which they
can feel the vibrations in the air.
Eye Of the Snake.
Snakes nave but poor eyesigat, and.
ike fish. have no eyelids. Their eyes
= are covered with a thin transparent
!, scale which is ever open. in sun and
t shade, at noon and midnight. in an aw-
! full, never winking stare. We cannot
/ imagine how sleep can ever come to
: such creatures.
\ Finally. let US turn to the most per-
r feet eye nature has ever produced. We
I can read and write and do many
: things by the aid of our eyes that are
4 forbidden to other creatures of the
earth, but this is because Of the brain
. behind directing the eyes. We can look
|. closely at the stars and we can watch
o the actions of a tiny dot of life many
: thousands of times smaller than a mote
! of dust. All this we can do by means
= of the two magic tubes" the telescope
= and microscope. But when the unaid-
. ed eye is alone considered, birds put us
= to shame. "Observe an eagle" writes
I. a noted scientist, soaring aloft unit
= he seems to us but a speck in the blue
: expanse. He is far-sighted, and, scam
Il lAli6 lAlS col II 49,
ject much smaller than himself. which
would be invisible to US at that dis
lance. He prepare to pounce upon his
: quarry; in the required fol
Q the deadly plunge he becomes near
8 sighted. seizes his victim with unearr-
e ing aim and sees we'll how to complete
the bloody work begun: A hummine
bird darts SO quickly that our eyes
cannot follow him. yet instantaneous.
settles SO light as a feather upon 6
o tiny twig. How far off 1t was wher
n first perceived we do not know. but IL
X the intervening fraction of a SECOND
IS the twig has rushed into the focus o.
distinct vision from many yards away
A woodcock tears through the thickes
cover as IL 1t were clear space. avoid.
ing every obstacle. The only thing:
to the accurate perception Of which
u birds eyes appear not to ave accom-
modated themselves are telegraph
ia wires and lighthouses. Thousands o
birds are annually hurled against thes'
IL objects to their destruction"
= Politics Pickin' Up.
n Atlanta Constitution: Politics il
pickin' up" said the old colored cam