The silver lance., 1897-07-23

w QaTk caves ua' 49,
eyes. In many If such animals, how
ever. the eyes have been overgrown py
the skin, so that these eyes would Dc
useless for vision, even If the animal
should come from its subterr anean
Aome to the ligh. OF day The same
is true of the mole and mouse tribes
Indeed. all the vertebrate animals nave
two eyes. whether they use them or not
Not all animals have these two eyes
symmetrically placed in the head, one
On each side Certain fishes which ap-
parently swim on the side, such as the
turbot. have both. eyes on the side-the
dark side Of the head. That this is not
due TO a simple twist of the head was
demonstrated by Professor Steenstrup
more than twenty years ago.
AT times. by what Is termed arrested
development. animals, and even human
beings, appear as cyclops. or having
one eye only. But who ever heard Of
third eye in man or beast? And yet
recent researches prove that man and
all vertehratcs seem to possess the ru-
diments CT third eye
This discovery is not only very inter-
esting. but also remarkably instructive.
since the rudimentary third eye of man
has. by one of the most noted philoso-
piers of modern days. been looked upon
as being the seat of the soul.
As organs by proper use develop in
strength and perfection, SO they be-
come weak by lack of use. II for many
generations an organ should remain
without use. its structure In time be-
comes simpler and more imperfect. II
such process continues throughout
ages, the organ. by constant disuse. will
become reduced to a mere rudiment Of
what 1t was In the species using the
same. Thus, species of birds that only
walk and run, but never fly, have only
rrdimentary wings. as the ostrich.
while In the eagle and the albatross
the wings are seen In a state of per-
fection.
Now. In closely examining the skulls
Of certain lizards. 1t was found that near
the top Of the head. under the dark.
opaque skin. and often in the very bone.
an almost perfect eye exists, though NO
ray Of light ever could reach it,
This eye shows a crystalline lens, a
retina Of very complex structure, and
an ootic nerve-in fact, all the essential
parts OF perfect eye. But being COW
cred by the Opaque skin of the animal,
It is absolutely useless.
II this optic nerve is traced to the
brain, 1t is found TO connect the eye
| with the so-called pineal gland Of the
brain. This pineal gland is, of course.
In no sense of the word a real gland.
hrVt n daHnffn aF -
tissue of the brain. invariably located
just back and partly over the cerebrum,
and In front of the rounded brain-mass
which generally is considered to cor
respond TO the corpora quadrigemina in
man.
This third eye of the spotted lizard is
called the pineal eye. on account of the
nerve connection of Its retina with the
pineal gland.
Now. while in certain lizards this
highly developed eye is useless because
It is covered by opaque skin, and in
others even deeply imbedded in bone.
1t would seem probable that in an
earlier stage Of development this pineaI
eye was not rudimentary, but in con-
stant use. A very slight modification
WoaAb ASSoAAPfASA tIiS-QdmeIN. the
transparency of the skin covering of the
eye. This is exactly the condition .f
the normal eyes in reptiles to-day: the
skin covers them, but it Is transparen.
where 1t passes over the eye,
In the skulls of some of the gigantic
reptiles of the earlier age Of this globs
paleontologists have long ago found a
large. round perforation. Probably hi,
was the socket Of the third or pineaI
eye Of the ichthyosaurus, the plesiosan-
rus and the labyrinthodon.
But much more important conc,,,-
sion must be drawn from this discov-
ery-nameiy, that in all yertebratos
even including man, the traces Of this
third eye remain to-day. The nine.l
sye OF lizards being connected with The
large pineal gland Of the same =,
would seem that the pineal gland itseIs
is but the nerve center of optic thaInns
for this third eye. In all reptiles ona
amphibia the pineal gland is large. sa
1t Is also in fishes, 81