The daily gazette., 1879-06-27
Color Blindness Among Railway
Employees.

The daggers and prevalence of color
blindness have only very lately been
brought 10 public attention in this coun-
try. Within the last few years, however,
the percentage of railway employees in
Europe incapacitated by this defect has
been determined by experiment, and the
need Of providing some remedy by legis-
lation has been widely recognized. A
movemenet in the same direction has
now been started in the United States.
At its recent session, the Massachusetts
General Court took measures to this
end, and the attention of Congress will
be called, at an early day, to the subject.
The importance of this matter has been
brought home to our community, mainly
through the lectures and writings of DR..
b. Ii. Jefferies of Boston, who has made
special study Of this curious visual
disorder.
Few persons have suspected the ex-
tent to which more or less serious varia-
tions from the eyes normal chromatic
power obtain among civilized nations.
Except in extreme cases, the patients
defect may remain for years undetected
by others, perhaps unknown to himself.
Even the statistics collected by earlier
observers were untrllstwoithy, owing to
the inadequate tests employed. Thus,
up to 1856 the surgeon of a certain
French railway only rejecting fifty out
Of five thousand candidates. On the
other hand, in the two years ending July,
1875, when the method of examination
was more rigorous and scientific, ninety
eight out of one thousand and fifty were
on this score found incompetent. In
1877 DR.. Favre found one hundred and
five color deficient in two hundred and
sixtyeight men belonging to French
regiment, and another surgeon reported
seventy-five color blind out of seven
| hundred and seventy-five French sailors.
OF all adults, indeed, examined by Favre,
the average was over sixteen to one hun
dred, and after comparing his own data
with other returns, he reached the con-
clusion that in + ance the color blind
amount to ten in one hundred of the
adult males.
The ratio would appear to be very
much less in Italy; but in Sweden, Ger
many, and England 1t is now. computed
at not less than one in twenty. We
should mention that the statistics in nc
instance include females, who, there il
reason to believe, are much more seldom
affected by this visual alteration. Never
theless, the study of color blindnes.
would seem to interest at least twenti
eth Of Our male population an
his proportion, measures the chances
of error in the various indus
tries where discrimination of color is
necessary or useful. 1t does not, oi
course, give an exact idea of the chances
of accident in the marine and railway
services, on account of accessory circum-
stances which the color blind in theil
embarrassment, and at which we will
glance presently.
AS rule, color blindness is congenita
and wholly beyond remedy, though i
may in some measure be palliated by tn
use of properly tinted glasses. In it
congenital form this defect is hereditary
and the remarkable certainty with whicl
. it is observed to descend has an obviou
bearing upon the question of frequency
which in turn determines the compare
tive peril to the community at large. Be
sides inherited incapacity, certain con
stitutional diseases may induce loss o
chromatic sense. So, too, tobacco ant
alcohol are found to frequently cause
failure of color perception, and ophthal
mic surgeons now lay stress on the ne
cessity of abstinence from these stimu
lants among railway employees and sail
ors. In such cases the treatment of tn
disorder is sug ge ted by knowledge o
the exciting cause; but art is powerles
to cure that form of color blindness re
sulting from inherited atrophy Of the OF
tic nerve.
t The inability to mix or use colore
! pigments in certail industries is, {
course, speedily discovered by the partie
: interested. But the perils to which til
! community are subjected from colo
/, blind railway employees and pilots ca
D only be averted by the action of the con
munty itself through its Legislature.
The attention of railroad manager
has, in Europe, been repeatedly calle
: to the grave danger likely to arise frol
A failure to distinguish between gree
and red ghts, or, in other words, b'
4 tween the safety and danger signals.
!. is true that the majority of even colo
l blind persons can discriminate brigl
:. red from bright green when they al
n near the eye and we'll Illuminated 81
q this power diminishes with distance
VI | very Idl)lu Idbio, 10 loeditt iluobl dtcu L
v certain atmosphere conditions, and
n seriously impaired even by the effect
n time in furnishing and darkening fla
= signals upon railroads. 1t is believe
# that not few marine disasters have n
n suited from the mistaken color of
n lighthouse, beacon, or harbor lam
s which, on strange coast and with pc
:. haps the accompaniment of snow storl
$ or thick fog, has been wrongly deciphe
a ed by a color-blind pilot. 1t is plai
q that on railways the hazard attendin
8 mistakes of signals is much create
+ We might imagine a color-blind rail
v road employee would be immediatel
f detected, or would have, at least, disco'
q cred his own deficiency. 1t appear
!. however, that, like the deaf, the victim
> of this incapacity learn to supplemer
weakness in one direction by develop
ing peculiar sensitiyeness in another
TO the color-blind, as also to the norms
4 eye, the green flag or lantern is undoub
Z edly deeper or darker, and the red MOI
: brilliant. The color-blnd employe
; learns to govern his decision by the il
tensity of the light and not the hue, an
may thus manage to avoid accideI
when the object is perceived under fl
vorable conditions of the atmosphere c
: at moderate distances. 1t is clear ths
: the quantity of light reflected will grea
ly vary, according to the nature of III
u Illuminating material or the tint an
:. | thickness Of the glass as we'll as th