San Antonio daily light. [volume] (San Antonio, Tex.) 1886-1907, 1892-08-22
Color Blindness and Tobacco Am.
blyOpIa.

Color Blindness and Tobacco Am
bIyOpIa.
Pail Mall Gazette.
The report of the committee of tn,
RIVAL society on "Color Vision,
with the accompanying minutes, con
tsiDs some curious reading. The
most practically important fac
brought out is that some OF the tests
now used for detecting defects o.
vision lie engine. drivers and seameu
are inefficient. Color blind men are
actually educated to pass the exam
nations, q profession OF what may be
called "color coaches having grown
up to supply this want. The art OF
examining surely never had q more
strange and, one may add, a more
mischievous application than this
| The committee had before them one
of these gentlemen, but they do not
give his evidence. Another witness J.,
however, explains their method
of proceeding. They provide them
selves with q set of colors similar to
those used in testing. A color is
shown to the pupil. 1t is, say, green,
aud he calls it red" Thereupon he
is instructed to answer "green" when
q thing appears to him red. The in
struction Is not, of course, so simple
as this would seem to make it out.
The color sensations are various in
various individuals, and different
till ts make different impressions; but
the example is sufficient to show the
method OF ''color coaching" The
committee recommends the univer.
sal and compulsory use of what Is
called "Holmgreen's test" This con-
sisis of a number of skeins of colored
wool. re examiner selects skein OF
q certain color-say pale grass green
and the candidate is requested to
pick out from the heap others of the
same type of color, irrespective of
shade. A color-blind person will
match drabs, pIDks and yellows with
grass green, blues and violets with
light purple or rose, and dark green
or light green with light red, accord.
ing as he is "red blind" or green
blind"
That accidents have happened,
either from the lnefficiency of the
test applied or from uone having been
applied at all, seems to be esta bIished
beyond doubt. In July, 1S75,a steam
tug and steamer collided near Nor.
folk, Va. The master of the tug
swore that the steamers red light
was exhibited. All the officers OF the
steamer swOre that the position of
their vessel was such that only the
the tug. The master of the tug was
found on examination to be color
blind. In this case the defect cost
the lives of ten persons. In another
case an accident was norrowly aver
ted. The third officer of a vessel,
seeing what he supposed to be green
light in an approaching ship, called
to the man at the wheel to "port.n
Happily the captain was on deck and
countermanded the order. 1t turned
out that the man was color blind. He
was removed from that ship, hut
probably followed his occupation
elsewhere. A somewhat alarming
fact is that temporary color. blindness
may be brought on by excessive
smoking. Tobacco amblyopia it lie
called, and it may be brought on, or
was brought on in case described,
by smoking "half an ounce of shag
daily" not an excessive allowance, by
the way. l. disappears when the
cause Is removed.
AS to the frequency of color blind
ness there seems to be a variety of
opinion, or, possibly, of experience
HOlmgreen found q percentage of q
little more than 3 in 80 165 men that
he examined. But IN 2l4 lads exam.
ined Tor naval cadetships in 1883 only
one color blind was found, and in the
two following years the percentage
was only OF and 1.31 1t is curious
tn be told that hundred girls eau be
tested in the same time as forty boys
Probably they are quicker and more
docile; but another witness tells Us
that colOr-blindness is very rare
among women.