The morning news. [volume] (Savannah, Ga.) 1887-1900, 1896-07-05
ANIMALS. WITHOUT EYES.
The Effect of Continuous Darkness
on the Optic Origins.
From the Popular Science News.

From the Popular Science News
one of the immutabe laws Of nature
declares that animals which are placed in
new surroundings, not fatal to .fe, under
go certain changes and notifications in
their anatomical and physiological struc~
lures to meet the exigencies demanded
by such a modification of surroundings
Thus. the founder and all its eongeners,
the turbot, the plaice, the sole, etc, were
centuries and centuries ago, two-sided
fishes, swimming upright, after the man
ner of the perch, the bass and the sal
mon, with eyes arranged on each side
of the head. From upright fishes, swim
ming probably, close TO the surface of
the sea, they became jewellers on it's bot
tom, and, in order to hide themselves
more effectually from their enemies or
their prey, they acquired the habit Of
swimming with one side next to the
ground and Of partially or wholly bury
ing themselves in the mud, always, how
ever with one side down. They thus be-
came fiat fishes, losing the colorng of
their undersurfaces, and their ewes mi
grating across their foreheads and taking
up positions on the upper surfaces of
their heads. Again when animals are
placed among surroundings in which there
is no need for. some special organ, this or
gan degenerates, and passes wholly or
partially into rudimentary condition, or
entirely out of eXis tence. These latter
effects of changed conditions on animals
are specially noticeable in the effect of
continuous darkness on the organs of
sight of those creatures which, owing to
said mutilations, have been compelled to
dwell in darkness for untold ages.
The mole, far back in the past, had eyes,
and gained its livelihood above ground in
the broad light of day, but owing to some
change in the surroundings 1t was forced
to burrow beneath the surface of the
earth; consequently, its organs Of sight
have degenerated, and are now practical
ly worthless, SO far as vision Is concerned
All moles, however, can tell darkness
from light; consequently are not totally
blind-a certain amount OF sight yet re-
mains. This is due to the fact that, al
though the optic or sight nerve, on exam
ination, is invariably found to be atrophied
or wasted, there yet remains In the shriv
eled nerVe-cord true nerve cells These
nerve cells transmit ghtsimpressions to
the brain. Even II the optic nerves. and,
in fact, all of the structures OF the eyes
were absent, / yet believe that the mole
could differentiate between daylight and
darkness. The sensitive nerve tufts and
ailments of the skin undoubtedly, in GER
tain Instances, respond to the stimulation
OF light, so that totally blind animals, an
finals with no rudimentary organs OF VI
sion whatsoeyers and the inception of
whose ancestors probably took place
thousands of years ago, show by their ac-
ton that light isIexceedingly unpleasant
to them. Thus, have seen actinophryas,
minute microscopic animaicules, taken
from the River Styx In Mammoth cave
(Which is their habitat seeking to hide
themselves behind q grain of sand that
happened to be drawn up In the pipette
and dropped upon, the glass slide beneath
the Obiect-glass of my microscope
have repeatedly seen the blind fish Of
Mammoth Cave seeking out the darkest
spots IN aquaria. In point of fact I think
Shat It san be demonstrated that light is