The Rock Island Argus. (Rock Island, Ill.) 1877-1885, 1881-06-11
CoLoR-BLINDNEss.
London Telegraph.

1t appears from the report presented to
committee of the archaeological socie-
ty by its secretary DIR. Bradley, that out of
Is, 0S8 persons examined (including boys
in Eton Westminster, and Christ's hospi-
tails and 8, 900 members of the metropoli-
tan police) the sight of upward of $50 per
sons was found defective. The average of
defect was 10 times as great in males as
among females or 4. rs in the former and
Il in the latter. Among women, also, any
but slight cases are very rare. Among
men, on the contrary; they form rather less
than half of theentire number. Therefore,
the pronounced cases are at least 2.5 per
cent, varying from this number in Elton
school and the professional class to more
than 3.5 in the police and poorer schools
of London. The main defect of the pro-
nounced cases, say in 2 per cent. Of the whole
number Of males examined, is an inability
to distinguish red from green. Red looks
to those so affected as very somber color
in all probability as some shade of dark
yellowish brown. Green is somewhat sim
liar to this They see other colors correct
~, and by contrast very strongly. Jews
are more color blind than any other nation
atty, and their defects are usually of the
pronounced kind The members of the
Society of Friends are rather more color
blind than the average, though the excess
of their defects is principally constituted
by the slighter forms of color blindness
i. e.. an inability to distinguish from each
other the paler shades of most colors. In
mates of deaf and dumb asylums are very
defective as regards colors.
Color blindness does not mean a want of
acquaintance with the names of colors.
Mistakes from this cause are avoided by
the mode of testing, which consists in Civ
ing the candidate n colored skein of wool
green to begin with, and asking him to
pick out of bundle all that are anything
like that color mot naming it,. No
notice is taken of inability to
match shades of the same color. People
who can not tell red woods from green also
fail to tell red signal light from a green,
Indeed, they often can not see the red
light at all unless they are much closer to
it than to others. Examinations have not
been made of railway servants in England
till quite recently and now on many lines
the system is imperfect and incomplete.
At sea no examination at all of common
sailors is made. A collision at sea occur
red near Norfolk, United States of Ameri-
ca, in 1876, in which ten persons were
drowned, owing to the captain installing
green light for a red. Five year later he
was examined and found to be color blind.
DIR. Bradley thinks that those who confuse
red with green see neither one color nor
the other but in the place of both some
neutral shade, such as gray. He thinks
that the greater deficiency of Quakers as
compared with others is due to the fact
that the poorer Quakers especially have
been for many generations very ascetic in
their houses and dress, avoiding the use of
all colors Also that the Jews have
strengthened their defects by the intermar-
riages which have been always the custom
of the race. He observes that the natural
love of dress and greater precocity of mind
at an early period of life have been the
cause of greater acutenesss of color vision.