The DeSmet leader. (DeSmet, Kingsbury Co., Dakota [S.D.]) 1883-1891, 1885-11-28
COLOR BLINDNESS.
INABILITY TO DISTINGUISH RED THE
MOST FREQUENT DEFECT.
Green the Next Color Most Frequently
Mistaken-Me More Affected Than
Women--Tests OF Color Blindness
Various Experiments
lDr. George S. Munson.l

The most frequent defect in color. blind.
ness is the inability To distinguish red. A
distinguished professor in an English uni
versity once wore IA scarlet gown through
the streets, mucn to the anu ement Of many
who saw him. On being asked by friend
what appeared to him u be the color Of this
robe, he answered, pointing to some ever
greens near by: ut seems to me TO resem
bic those as closely a. possible" The next
color most frequently mistaken for soEe
other is green. The Importance Of this de-
feet is estimated by tho frequency Of it
occurrence. Ii it occurs only once in 10 OOc
persous, it is OF course of le S Importance
than If happening once In l00
Men are more frequently effected with
this defect Of vision than women. The de-
feet, when il is congenital, as it is in most
Of the cases under the observation Of physi
clans, is incurable. 1t is sometimes induced
by immoderate use of tobacco or liquor. Az
many as one IN twenty-five Of the men EN-
poyed on lines of travel arc affected by this
inability TO distinguish red from green. Ths
color blind In ca5e of accident by travel on
land and sea can not readily be detected be
cause of the difficulty OF tracing the cause.
OF ito accident. One thus affected can not
tell rel from green light, but one Of these
lights app,ars darker or less bright TO him
than the other.
the test Of color blindness is not how well
one can name colors, but how much he sees
them. Ii two letters be drawn, one red and
another green, on q background, a person
who is red blind will Distinguish only the
green letter, and party who is green blind
would fail to distinguish or see the green
letter In other words to the rst the red
colCr is suppressed and to the secoad the
The rod lliul will rlaca m rtfry,ta m
green alongside of rose color. suppo ins
them all to lie the same shade. The green
blind will confound the blue and tie gray
with the rose color.
The test FOR al engineer Is not 10 name
colors ami shades OF color, but to know red
"a red and green as green, and to m itch red
with red anu greon with green of their
various shades. Four per cent. OF the 80, ,00(
employees Of the Penn lvania railway
have Leen found totally color blinl. and
I'D per cent more or less affected
with thi' defect OF vision. Five p,r cent. of
the same were found with imperfect hear.
ing. In this city lives well known animal
painter who is entirely color blind. He 80
lecto his color not by knowing thu color
itself, tut by reading their names on the
tube He employs u'ually only black,
brown and wbiDo In his work.
DIR. J fries, of Philadelphia, instituted
very efficient test OF color-blininess by sus.
pending numbered skeins Of worsted of diff
ferent colors from rod. The standard
colors Of rose red. and green, with all the
various shades Of these colors. were mum
Lerei with the odd numbers All other col
ors were numbered with even hunters. The
person' examined for color blindness wers
invited to match shades Of the three named
before as the standard, and il any so named
~ere aiiiuiis these nurnbared with Tho
numbers it was seen at oncs that they vert
unable to distingu, n colors