Iowa County democrat. [volume] (Mineral Point, Wis.) 1877-1938, 1884-02-29
WONDERFUL INSECT EYES.
Where the Gift of Sight is Most Richly
Bestowed.i
London Globe

Physicians call attention to the in
creasing instances of defective or i'm
perfect sight occurring in civilized
countries, and attribute it to various
conditions of modern life-the over
work of the eyes in childhood, the
study of books in small print, and the
habit of reading by imperfect light.
and many other causes. 1t appears
certain that in the matter of eyesight
the savage has usually the advantage
of the civilized man. The gift of sight
is one unequally distributed among
the animal world. Some creatures
enjoy it to excess, like the eagle; 9th
ers are totally deprived OF it, like the
earthworm.
In many other instances the sense
of sight, if no actually lacking, is ex-
tremely imperfect, as in the case of
the mole. Insects are in many cases
far more richly endowed with eyes
than even birds or beasts. The little
creature called the whirlwig which
skins along on the surface of stand
ing water, is furnished with double
set of optics, the upper portion of the
eyes fitted for seeing the air. being
placed in the upper portion of the
head, and the lower portion OF the
eyes Gifted for seeing in the water) in
the lower portion of the head, a thin
division separating the two.
Spiders possess six eyes-some spe-
cies eight; centipedes twenty, while
the eyes of many insects (bees, butter
| flies, dragon tlies) are composed of a
number of facets, each eye being, in
fact, a cluster of eyes. DR.. Hook
counted IA, 600 of these facets in the
eye of dragon fly, and Leeuwenhock
found as many an 10, 544 in another
specimen of the same species. The
latter naturalist adapted one of the
eyes of dragon-tiy so as to be able to
see objects through it by means of a
microscope, and found that he could
view the steeple of a church 299 feet
high and $50 feet from the place where
he stood; he could also distinguish il
the door OF house, at the same dis
lance, was open or shut.
Fleas' eyes diminish as we'll as null
tiply objects, as Puget discovered by
performing similar experiment to
| that of Leeuwenhock. ga soldier
viewed through itrepresented an army
of pigmies. The flame of a
candle seemed the illumination of a
thousand lamps" Blind or imperfectly
sighted human beings may think with
envy of the beautiful provision of
visual organs bestowed by nature on
some of her children; and yet many
creatures live happily with but small
share of the blessings of sight. In
some of the insects who possess the
largest share of visual organs some
other sense--taste, hearing or touch
| is deficient Huber believes their sense
of both hearing and taste to be Imper-
| feet.
On the other hand, the blind earth
worm will retreat rapidly into its hole
if the light of candle is thrown upon
it, its sense of hearing or smell warn,
ing it of the approach of the danger it
cannot see. A bats senses of touch,
hearing or smell are so acute that il
depends little on the aid of its eyes.
Spallanzani tested this by the cruel
experiment of destroying the sight OF
several bats and then setting them
free, In their flight through the
room they avoided even the smallest
thread placed to obstruct their way.
Latreilla, the French naturalist, states
that there is a species of ants which
are entirely blind, but pursue the
same mode of life as their sighted
brethren.