The Lebanon express. (Lebanon, Linn County, Or.) 1887-1898, 1888-02-24
COLOR-BLtNDNESs.

A Defect of Vision which Is safd &c BE
Largely Hereditary.
The defect OF vision known as color
blindness is a very curious one. II
consists OF either total or partial lack
of ability to distinguish color. whils
the sight may be faultless in every
other respect When total. the sensa-
ton of color Is absolutely wanting.
and the individual sees only different
shades of white and black. These
cases. however. are. extremely rare-
More common il partial color blind
ness, where the sen ;ation is defective
i'm relation to Ger. ain colors, Dnt not
to all This is of three kinds-red-
blindness. green blindness and violet
blindness Cases of the last variety
are SO seldom met with that the term
color-blindness. as commonly used.
has references TO either blindness
or blindness
p rsons who are rcd-blind see all
red objects as a shade of gray. and the
same is true of the green blind as 10
green. A mixture Of white and black
in proper prop lrtions will give to the
r-blind the same sensation rs the
different shades of red and green. It
Is somewhat singular that while there
is no reason to doubt that color blind
ness is as old as man. it was not dis
tinctly recognized aud accurately de-
scribed until little more than hum
dred years ago.
The first case on record is that of n
shoemaker named Harris. who lived in
Mayport England 1t IS said that his
arst suspicion of any peculiarity OF
vision on his part arose when he was
about four years old Having by acct
dent found q chiId's stocking in the
street he carried il to house near by
to inquire for the owner. He noticed
that other people called it red stock
ing. but c,,uld not understand Why
they did so. as it seemed to him COM
pletely described by calling it =
stocking. He observed. also. that
while the children with whom
he played could distin guish
The cherries on q tree by some pre-
tended difference Of color, he could
only tell them from the leaves by their
difference in size and shape. H. found.
too. that by means of this diff :rence in
color. or in some way which he could
not understand. they could see the
cherries at greater distance than he
could, though in cases where their
sight was not assisted By the color.
ne could see objects at as great dis
tanee as any of Them
This case was described in 1777.
Seventeen years later the celebf ated
English chemist. Ddlton. DESERVED his
own case 50 accurately and minutely
sliat color blindness in general. and
especially the form of il with which he
was afflicted namely, red blindness
has since been known as Daltonism.
He says that he was never convinced
of any popularity of his vision until he
accidentally observed the color of the
| flower gerdniun zona!e by canslielight
The flower was pink. but appeared TO
him almost an exact sky-blue by day.
By the light of the candle, however, il
seemed to him not to have any blue in
it. being what he called red-a color
which forms a striking contrast to
blue. His friends to whom he re-
feFred the matter. agreed that the
color was not materially different from
what it was by daylight except his
brother. who was subject 70 The same
defect a. himself Two years after
ward he began TO investigate the SUBJ
| ct of eolors. or color-bliFdaess- Ha
found that he could distinguish bat
two. or at most three, coiors in the
rainbow. These were yellow and
blue. or yellow. blue and purple. His
yellow included the green. yellow.
orange and red of others This was
the same DR.. Dalton who afterwards.
though a Quaker and eonscienfiously
opposed to wearing bright colors. when
he had received the scarlet gown
| of q doctor of laws for presenta.
| tion at court. not only donned it with
| out objection. but also wore it for sew
eral days upon the street. in happy
Inconsistencies of the effect which hs
produced.
Color-blindness is largely hereditary.
| and affects males much more frequent
" than females 1t exis from birth
| and there is no means known By which
it can be remedied A temporary
condition of color-bIindness is occa.
sionally met with. due to disease OF
injury. which passes away with the
condition which produced it The
existence of color-blindness in persons
occupying responsible positions in the
railroad and marine services is q
source of great danger to the travel
| ing public. and in most countries ex-
am:nations sre provided by law. ( j
the purpose of testing the color per
ception of all applicants for These
Golden Days.