The Salt Lake herald. [volume] (Salt Lake City [Utah]) 1870-1909, 1897-02-21
HOW DID WE GET OUR EYES.
a Learned English Professor Gives
the Result of His Recent Re
searches.

The ancient question: Can matter
think? is now matched by a much more
interesting and profitable one: Can the
human eye see? The latest inquirer in
this field answers bluntly not only. that
under proper conditions it can, but that
ii is precisely by this means that we do
see; that, in short, the eye is simply a
modification of the tissue which covers
our bodies. Precisely how this modifi-
cation has come about and the marvel
/ ously intricate and sensitive mechan-
/ ism by which we become aware of the
external world been developed is a
wonderful chapter. 1t has been worked
out in detail by H. NJ. Barnard of Cam
bridge, England. building on the found
atoms laid BIZ GRAFT Spencer. Ian
kaSter and others. Before all il is
necessary to understand how complete
ly latter day science has revolutionized
the old and once universal view that
the world was made for man, and that,
for example, the commonest color in
nature was green because it was the
most restful and grateful to the eve
The present view is exactly the oppo-
site. So far from the earth having been
made for man, the latter represents
simply an adaptive development from
the lower orders of life and all our
organs of sense, like those of other ami
mails, have arisen simply in response
to the call of nature. The conclusion of
Mr. Demands long and beautifully.
conducted research is that the eve
arose as local modification of tissue.
induced by the excessive crowdine of
the augmented granules at spots most
frequently and brilliantly Illuminated.
and that this crowding of the pig
mented granuleS explains both the
origin of the eye itself and it's func-
tons as an organ"
Astonishing as this view at first ap-.
pears, its probability becomes evident
as Mr.. Barnard leads the reader
through the maze of primitive organs
with which nature first made an at
tempt to utilize light as an aid in the
struggle of her creatures for existence
II a piece of ordinary skin, say of the
thumb, is cut across, it will be found
TO consist of a stratified series of diff
ferent types of skin, very much like
unto the different layers shown in an
outcropping of rocks
In lnvertebrate animals the skin is nor
greatly differentiated while in the var
tebrates its layers are sharply defined
rms has given rise to two different tvpes
OIL eyes, the .pineal eye" and the verte-
brate eye proper. The dissection of a
Skull Will show back of the eyes n conf
cal body known as the pineal gland that
was once supposed to be the seat of the
instrument with which the developing
animal gained sight The retina mere. ac-
cordlng TO Mr.. Barndrd'S technical de-
scription. arose by a secondary multi
plication of the epithelial sensory cells
Tor the appreciation of the variations OF
intensity of irritation caused by the
movement of the pigmented granuies of
the skin toward the exterior while the
cloptrlc apparatus arose from the ac-
cumuiatlon at the surface of slime wholly
or partially produced by the excessive
discharge Of the pignented granules.''
In little simpler language. when
strong light fell upon the sensitive its
sue OF the as yet blind animal this set
up an irritation which resulted in the ac-
ccmuiation at the surface of the skin of
minute particles drawn thither as water
is lifted up by the sunlight int5 ,he
clouds. This Watery and hence retroactive
mass would eventually be enclosed by a
process of imagination. a very common
brought the pineal eye to its highest
functional level AT this point il began
TO decline and is now merely vesri-a
Formed when our remote ancestors pos :
sessed only an undifferenticted euiderrnis /
OF the inVertebrate type, in the process of /
time when the skin lost this simple char /
acter and began TO consist of a number I
of different layers, the pineal eye gave (
way 10 another of far higher powers 1t I
is the view of Mr. Barnard that one series
of cells budded off from the ..nal.sade''
layers-a name derived from their an
pearance in cross sections, while others |
the pigment-bearing cells. for example
migrated through the palisade layers /
wholly new type The cells OF the pail
SADIE layer will now be irritated bv the
variation in Intensity of the pressure of /
the pigment matter traversing them
under the attractive action of the light.
and these cells become sensory by as