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Color Blindness in its Relation
to Railroad Employees and
the Public.

With the Compliments of the Authvr.

Color Blindness

IN ITS KKLATION TO

, ^

RAILWAY EMPLOYEES AND THE PUBLIC,

G. STERLING RYP^RSOf:, M.D., CM., L.R.CS. EDIN.,

I'rofessor of Ophthalmology iu Trinity Medical College, Toronto.

A Paper read at the Cayiadian Institute, Toronto, at the
regular Meetiiig, Saturday, Feb. 9th, 1S89.

TORONTO :
J. E. BRYANT & CO.. MEDICAL PUBLLSHERS.

■' ,, . i;

64 HAY STRHKT

OKMCK ()K

J. H. Bryant & C

Medical Publishers.

I>(;ah Sir.

'I'okonui, Marcli j-nl, i8S.,.

Wo have „„,cl, pleasure in presenting you, with ll,e
.■on,plin,en,s „f ,he .iistin,uishe4 author, the en,:l„se,l „,onograph
"n •■ Color l,lindness, in its relation to Kailwav l-anplovees an.l
•1- l'ul.lic, ■■ This suhieet i.s so in,p„rtant in itself, .n,l so
certain to arouse puhlic interest when on,:e thorough,,. understoo.l,
that we feel ,,ui.e sure you will not regret our hringing un.ler
your notice the sucine, and luc-id exposition of i, .hi.h the
author ha.s here presented. And should you he in<luee<l ,„ assist,
«. far as lies in your power, in the fornration of an enlightened
P"''l"^ "Pinion in regard to the nratter, Or. Rverson, we are
confident in saying, will feel that he has been largely rewarded
for the pains he has taken and the e.xpense he has incurred in
maktng known ,o the public the latest results ot scentific enquiry
in respect to it.

Vours, very sincerely,

J. E. B

RYANT & C

> 7,

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f^-^' .,v.'- -'' '^"^

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Mr. Prfsiihnt tnicl (rentlemen .

'.'( :■ t ;*'

•v;.r''^

For our knowledge of this most important suliject we are largely
indebted to the labors of Profs. Seebeck and Stilling, of (Jerniany ; Prof.
Wilson, of Edinbuigh ; Prof. Holmgren, of Sweden ; Prof. Donders, of
Holland, and, on this continent, to Dr. Joy Jefiries, of Boston, and
Prof. Wni. Thompson, of Philadelphia, to both of whom 1 am much
indeV)ted for advice and information, and from whose writings I will
frequently cjuote.

As in other scientific matters — practical tests must have some The-
oretical HASis. In this matter it is fortunate that both theory and
practice agree. The theory of color which .students of Color Blindness
have adopted is that of Young, revived after nearly a hundred years of
oblivion, by Helmhoit/,.*

As regards the different Varieties of Colok Blinmjness, Dr. Joy
Jeffries, in his book on '' Color Blindness,' thus quotes Holmgren's
work : —

"We classify the different kinds of color blindness under especial
heads, to be able the better to grasp the whole. \Ve might, indeed,
divide this blindness into congenital and acquired ; but as such a divi-
sion has reference alone to the mode of origin, and not to the nature of
this blindnes.s, and affects in no wise the manner of its discovery, it has
no practical importance in the case now occupying our attention. Be-
sides, our division relates, as does our entire memoir on this subject,
essentially to congenital color blindness. The division is as follows : —

"I. Total color blindness, in which the faculty of perceiving colors
is absolutely wanting, and where the visual sense consequently can only
perceive the difference between darkness and light, as well as the dif-
ferent degrees of intensity of light.

* The well-known Youug-Helmholtz theory, and its application to Color
Blindness, was here explained in full.

"II. Partial color hlindnoss, in which the faculty of certain percep-
tions of color, but not of all, is wanting'. It is subdivided into —

" 1. Complete color blindness, in which one of the three fundamen-
tal sensations, one of the three perceptive organs of color in the retina,
is wantinf,', and in which, consequently, the colored visual field has but
two rani^'es. This group includes three kinds, namely —

" (a) Red-blindness.

" (h) Green-blindness.

"(r) Violet-blindness.

" '2. Incomplete color blindness, where one of the three kinds of
elements, or perhaps all, are inferior in excitability or in numbers to
those of the normal chronmtic sense. IncoJiiplete color blindness ex-
hibits, like the nornml sense, three zones in the visual field, but is dis-
tinguished from it by an unusually small central field. This group
includes the whole of a series of different forms and degrees, a part of
which — the superior degrees, which might be cali' d incomplete red-
hlindnrss and incomplete yreo.n-hlindnesK (and incomplete violet-blind-
fiess) — constitutes the transitions to the corresponding kinds of complete
color blindness ; and another part of which — the inferior degrees, which
we call a feeble chromatic sense — constitutes the transitioii to the normal
sense of colors."

The various methods op testing for color blindness are those of
simultaneous contrast, complementary after images, 8tilling's method,
Maxwell's disc, Woinow's discs, Donder's, Chibret's and Holmgren's
tests. Testing by lanterns and flags is tedious and uncertain. The
best general method is that of Holmgren."'^

The Causes of Color Blindness are congenital defect, heredity,
severe illness or injury, particularly to the spine and head, excessive
smoking and drinking.

So far as tests have been made, all nations have shown a certain
percentage of color blind persons, even the North American Indians.
From two to thirteen per centum of the population are color blind. So
that, on an average, one in every twenty-five (25) is so aflfected.

* These tests were fully explained and in some instances demonstrated.

tain percep-
into —
> fundamen-
{ the retina,
iekl has but

•ee kinds of

numbers to
)lindness ex-
d, but is dis-

This group
ieH, a part of
ooniplete red-

violet-blind-
s of complete

grees, which
,0 the normal

are those of
ng's method,
Hohugren's
ertain. The

3ct, heredity,
d, excessive

>wn a certain
ican Indians,
or blind. So
'ected.

loustrated.

TiiF, Influknck of For,, Mist, Snow and Steam on Sional Lir-iiTs
is very important. A white lantern exposed to snow and rain, by ab-
Horptio!\ of li},'lit from the dimmed ghisH, may appear j^rcen to the color
blind, who depends on the intensity of the li,i,'ht to guide him. So, also^
may a green liglit appear red. \\y tlm accidental use of thieker and
dark»'r green glass or thinner and brighter red gla.ss, the did'erence in the
intensity of the light may be destroyed, and hence arise all the condi-
tions for the occurrence of dangerous mistakes. Steam also afFects the
color of the light. As seen through ditrerent degrees of pressure, it
may appear red, :roen, or violet. The importance of this fact is self-
evident.

E.\p(!rience and experiment show that we are forced to use red and
green lights i vessels, nnu at least red lights on railroads. Some roads
have discarded gr» i and use only red. Form cannot be substituted
fur color at nigla, ;.s the rapid movement of the train alters the appear-
ance of the lights, and thus mistakes may arise.

It should always be borne "m mind that the color blind judge of color
by the intensxty of the liyhf a/ouf, and that turning a white lig^^t up or
down represents to him different colors. VV'itli regard to this, \)v.
Wilson, of Edinburgh, writes : " How often it must fall to the lot of
engine drivers to watch lamps through an atmosphere wliich will con-
vert the safety signal (white) into a danf'er signal, eompletely alter the
color of the lantern signal (green), and so darken the danger signal
(red) as to render it invisible." Dr. Joy Jeffries, of Bo' ton, further
remarks : " In the even slightly color blind these chaUgjes will be inten-
sified, and to the completely color blind, his only moans of distinguish-
ing the signals will be gone, viz., the difference in the intensity of the
light."

Dr. Joy Jeffries elsewhere says : "A red and a green light appears
to excite one and the same element in the retina of the red-blind. A
ray, red and green, must seem fundamentally to the red-blind to be one
and t^e same color, and if, in especial cases, he knows how to discrim.
inate, his judgment is simply guided by the intensity of the light.

" If, then, a red-blind individual finds that a red and a green tint are
exactly alike, it is necessary that the green be to the normal eye much
less intense than the red."

■ (

"■ii"l""^i«W"l

^mammmm

This corresponds with what has already been stated. It cannot be
too often repeated and insisted on, that it is the intensity of the light,
and not the color, that the color blind judge by, and hence the great
danger of employing even partially color blinds as engine drivers, etc.

I would like to emphasize the fact that injuries to the head, severe
illness, and the excessive use of alcohol and tobacco, especially the
latter, are causes of color blindness.

Now, the reason that accidents directly traceable to color blind-
ness are not more heard of is, that the public are not informed of any
minor accident which occurs, and, even in more serious ones, reporters
have ditticulty in getting at all the facts. Also, because familiarity
with the road teaches engine drivers when to expect certain signals, and
that it rarely happens that both engine driver and fireman are color
blind, though such an unfortunate event has occurred.

Having thus, as far as limited time will permit, discussed nature,
cause, peculiarities and mode of detection of color blindness, I invite
your attention to the remedy for this condition. Color blindness is,
when congenital, incurable. When caused by disease or injury, it may
be cured. Exercising the ears with the names of the colors, and the
eyes with sensations of color, help the color blind to supplement their
eyes, but do not increase their color perception. They are often quite
unconscious of their defect, and are greatly surprised when informed
of it. Others know the fact and seek various ways of escaping detec-
tion. Color blindness, due to alcohol and tobacco poisoning, is easily
recognized by the oculist, by means of an instrument called the peri-
meter.

There is no reason why railroad officials should escape their percen-
tage of color blindness. The remedy here is the elimination of rail-
road employees toho are color blind. These employees comprise the
engine drivers and firemen, pointsmen, conductors, signal men and
station masters. I mean, that men of these particular classes found to
be color blind should be removed to positions where the color sense is
not essential to the performance of their duties. This is equally in
the interest of the travelling public, the railroad authorities and share-
holders, and of the men themselves. The public demands that rail-

[t cannot be
)f tlie light,
ce the great
drivers, etc.

lead, severe
pecially the

color blind-
med of any
es, reporters
familiarity
signals, and
,n are color

ssed nature,
less, I invite
blindness is,
ijury, it may
ors, and the
enient their
often quite
en informed
aping detec-
ing, is easily
ed the peri-

their percen-
ttion of rail-
•om prise the
al men and
ises found to
:olor sense is
is equally in
3s and share-
Is that rail-

road travel shall be made as safe as is possible, and by the proper
elimination of the color blind, a great source of danger is removed.

The ojfficials of a road that, through carelessness or other cause, allow
a color blind engine driver to run an engine, should, in (he event of a
fatal accident, be held guilty of manslaughter. Should injury or death
to a passenger resulting from an accident be proved to have arisen
from color blindness of an oiiiiial of the train, heavy damages could
be obtained from the company on whose road the accident occurred,
because the accident would be recognized as preventable. When
one has occurred amongst us, as has been proved to have liappened
elsewhere, the community will awaken to a sense of the danger. I
need hardly point out how serious is the risk of financial loss to the
stockholders. The destruction of rolling-stock and the liability for
damage to freight in course of transportation, and for actions for
damages by injured passengers, might easily cause a loss of thousands
of dollars.

Now, it will be said by railway officials, that the men of thfir res-
pective companies are tested for color blindness. I may reply, by
anticipation, that I have made it my business to enquire of all en-
gineers, firemen and other railway employees, with whom I have come
in contact, for the past three years, as to the tests made, and I have
come to the conclusion that they are imperfectly carrried out. Not
from any under-estimation of their importance, by the officials, but
because the tests are not properly and scientifically conducted. Men
with good color sense may be, and probably are, refused promotion as
being color blind, and men with imperfect color sense are passed as
being normal-eyed.

This state of affairs is as unfair for the men as it is unsafe for the
public. I feel sure that an examination of five hundred to one thousand
employees would show a certain per-centage of color blindness. The tests
I have shown tornight seem very simple, but in the case of men who are
constantly exercised with signals, their power of discrimination of color-
tone (not of color itself, that is never changed) becomes remarkably
increased, so that considerable experience and knowledge of the science
of colors are required to detect them

It may be argued by the companies, that 1 desire to put them
under the rule of an army of doctors and involve them in great ex-
pense. I desire nothing of the kind. I see no reason why the
Divisional Superintendents should not carry out the tests when they
have beeti properly instructed in them by an expert. I think also, that
it is not right that a man should be refused employment, dismissed
from the road or refused promotion, on the ground of alleged color
Idindness, except upon the certificate of an expert.

Furthermore, I insist that it is imperatively necessary, in the in-
terests of all parties, that every man should be re-examined periodically^
and more especially after an illness or severe accident.

The process of examination and elimination of the color blind on
railroads, has, in most continental European countries, been controlled
and directed by their respective Governments. In tiie United States
various plans have been followed. In Massachusetts, Connecticut,
Alabama, and other States, the examination has been contiolled by
law. In others, as in Pennsylvania, it has^ been left in the hands of
the Railroad Companies. The Companies have not been slow to
recognize the importance of the proper tests being made, and great
numbers of men have been examined and a varying percentage of
color blinds has been found.

In this country these examinations have been, and are entirely in
the hands of the Companies. If the Companies will have the tests
conducted in such a way as to secure absolute elimination of the color
blind, the matter might be left in their hands. But if they show care-
lessness or indifterence about it, legislation must be sought that will
place a supervisory power in the hands of the Department of Railways
and Canals. Just as sailors desiring masters' certificates are required
to pass an examination in color-sense before a Government Inspector,
so must engine drivers, etc., be called upon to prove their color-sense
and visual acuity.

In conclusion I would say that it is my belief — '

1. That the color tests, as made on railways in Canada at present,
are imperfect.

2. That danger arises to the public from this cause.

3. That it is urgently necessary that this danger be obviated by
the proper elimination of the color blind from among the employees.

4. And that the men should be re-examined periodically, and more
particularly after severe illness or injury.

I am so convinced of the correctness of my opinion, that I am will-
ing to examine here from five hundred to one thousand engine drivers,
firemen, brakemen and signal or pointsmen, free of all cost, provided
that they are not specially selected, and on this condition : that if I
find one per cent, or upwards of color blinds, I shall be paid by the
Company for my services at a rate to be agreed upon beforehand. If
I do not find this percentage of color blindness, 1 am to receive nothing.
The color blindness will be proved to be such to the officers of the
Company.

I do not put a higher percentage than one per centum, because the
proportion of color V>linds to the normal-eyed community has never
been detei'mined in this country ; and while it may prove to be higher
than in other lands, yet, results might show it to be lower. I am now
engaged in testing the school children of this city with a view of deter-
mining this question.

ely in
tests
color
care-
t will
ways
uired
ector,
sense

APPENDIX.

The following table, from Joy Jeffries' work, gives some idea of the
numbers tested and the percentage of color blindness found, in Europe
and the United States : —

Dr. Fontenoy ..
Prof. Donders..,

Dr. Krohn

Dr. Minder

Dr. Daae

Dr. Cohn

Dr. Magnus...

Dr. Stilling

Dr. von Reus-s.
Prof. Holmgren

II '"

It
Dr. Jeffries

Copenhagen j 1,084

Utrecht : 2,300

Fiulanil i 1,200

Berne j 1,429

Norway i 205

Breslau I 2,429

" i 3,273

Cassel i 400

Vienna \ 800

Sweden | 3,654

i 8,682

1,523

2,752

" ' 555

! 7,953

I 4,225

I 1,851

1 i 649

.321
10,387

Position in Life.

New England ...

2.87

152

6.60

5.00

6.58

4.88

4.00

3.50

6.00

3.50

166

4.54

300

3.45

3.08

105

3.81

4.50

171

2.15

2.22

3.34

4.77

5.60

431

4.149

Railroad employes.

Schools and various.
School boys.

Railroad employes.

i< fi

Scholars.

Students.
Orphan children.
Young people.
Railroad employes.
Sailors.
Soldiers.
Mill-hands.
Prisoners and g'rds.
Teachers and sch'rs.