Color-blindness : its dangers and its detection

Front matter

0 lor- Blindness

EXPLANATION OF THE COLORED PLATE.

Repeated and inexcusable mistakes have been made in Europe in reference to this colored plate of Prof. Holmgren. It has been spoken of as if intended to be used to test for color-blindness, and has also been so used. But, as he expressly states, it is only intended to illustrate the characteristic mistakes of the color-blind, and the colors of the sample worsteds to be employed.

II Red BJu> d/i ess

8 9

II

Green Blindness.

lib tO it

II

Red Bhndness.

II

Green Blindness.

»KwSTft0rlO & CO

This colored 'plate is not ititended to lest co/orh/mobiessiu,I>ut o/a d/ustrate the method oftcxtirm mid the mistakes of the co/orh

ITS DANGEKS AND ITS DETECTION.

BY

B. JOY JEFFRIES, A.M., M.D.,

(HARVARD,)

Fellow of the Massachusetts Medical Society; Ophthalmic Surgeon Massaehusetti Charitable Eye and Kar Infirmary, Carney Hospital, and New-England Hospital for Women and Children ; Member of the National Periodic Congress of Ophthalmology, American Ophthalmologics] Society, Boston Society of Medical Sciences, Boston Society for Medical Observation, boston Society of Natural History, etc.

REVISED AND ENLARGED EDITION.

BOSTON :

HOUGHTON, MIFFLIN, AND COMPANY.

NEW YORK: 11 EAST SEVENTEENTH STREET.

Copyright, 1879 and 1883, By B. JOY JEFFRIES.

All rights reserved.

TO

FRITHIOF HOLMGREN, M.D.,

PROFESSOR OF PHYSIOLOGY IN THE UNIVERSITY OF UPS ALA, SWEDEN,

THIS VOLUME

IS RESPECTFULLY DEDICATED.

""Why should we look one common faith to find, Where one in every score is color-blind ? If here on earth they know not red from green, Will they see better into things unseen?"

Dr. O. W. Holmes: Andover Poem, June, 1878.

Contents

PAGB

PREFACE vii-xiii

INTRODUCTION xv-xvi

Preface

I have dedicated this volume to my friend Professor Holmgren, because I consider that to him above all others do we owe the present and future control of color-blindness on land and sea, by which life and property are safer, and the risks of travelling less.

To his Majesty the King of Sweden are due the thanks of all for his personal interest in the investigation of color-blindness, and his practical good sense in immediately putting into execution the plans and proposals of Professor Holmgren, by which the subject was so prominently brought forward as to command the attention and example of other nations. It is earnestly hoped that this country will follow rapid suit.

Professor Holmgren's book on "Color-Blindness and its Relations to Railroads and the Marine " was published in Swedish, in 1877, at Upsala. Immediateby after this a French translation was printed, which soon called very general attention to his labors and their results. An authorized translation into German appeared last year (1878). I had agreed with him to translate the work into English, when an abridged translation appeared from the Reports of the Smithsonian

vii viii

PREFACE.

Institute at Washington. This, of course, prevented any publisher from being willing to risk a complete translation. The very necessaiy explanatory colored plate was not given in the Smithsonian translation. I understand that it will be in an extra edition. This English translation is so abridged as to greatly interfere with its value and its practical use.

Had, however, I been enabled to reproduce Professor Holmgren's book entire, I am afraid it would not have accomplished its purpose so well in this country as in Europe, from the general lower tone of scientific knowledge on the part of those for whom it was especially written, and also the lack of just the persons — namely, the railroad-surgeons — who could make immediate application of the method for detecting color-blindness, and have convinced the authorities of its necesshy. Aside, also, from the difficulties of publication, I found that a simple translation was not likely to be so generally read.

To bring before the community the dangers and the prevalence of color-blindness, I thought it best to prosecute my researches amongst the places of learning and teaching. Hence I chose our immediate universities, colleges, and public schools. Thus, whilst I was pursuing my own individual studies of color-blindness, I was at the same time gathering the necessary statistics in proof of the position I took, and disseminating a knowledge of the whole subject, ve^ especially the important one of its frequency. It is rather curious that this volume is only the third monograph in book-form on this subject. Professor Wilson of Edinburgh published in 1855 a small book, being a collection of his several articles on this subject. Yet the literature of normal and abnormal chromatic power is pretty ex-

PREFACE.

ix tensive, as may be seen by the bibliography appended to this volume. I first publicly discussed the subject before the Boston Society of Natural History, March 7, 1877. An article of mine on the "Dangers from Color-Blindness in Railroad Employes and Pilots " was printed in the Ninth Annual Report of the Massachusetts State Board of Health, 1878. April 8, 1878, I gave a lecture on color-blindness before the Society of Arts of the Institute of Technology in Boston. Feb. 23, 1878, I read a paper on the " Incurability of Congenital Color-Blindness " before the Suffolk District Medical Societj^ in Boston, published in " The Boston Medical and Surgical Journal" March 28, 1878. May 25, 1878, 1 read a paper on the " Relative Frequenc}^ of Color-Blindness in Males and Females " at the Suffolk District Medical Society, and also at the July meeting at Newport of the American Ophthalmological Societ}" ; published, July 26, in " The Boston Medical and Surgical Journal." The substance of these papers is included in this volume. I have quoted largely from Professor Wilson's book, not only because it is quite out of print, but also because the cases he relates are interesting as being in England, and his deductions are truthful and valuable, although much of the theory presented is now old to science. I have given a good part of Professor Holmgren's book, including what is essential to be known and understood by our railroad authorities and the specialists they must employ in carrying out any system of thorough examinations. The explanations and directions may seem to many unnecessarily minute, and the description too extended ; but ihese are especialby intended for examiners, who, I think, when using this test, will thank me for putting them within their easy reach.

PREFACE.

The importance of this whole question of color-blindness I need not insist on here. "The Kailroad Gazette " of Jan. 24, 1879, after discussing the 740 accidents by which 204 people were killed and 756 injured, says, " What most needs doing now is the improvement of the men who work the roads, — officers and employes, — though there is still plenty of room for progress in the tools with which they work."

I have not in this volume entered into the loss of time and money from color-blindness in the great industries where a perfect chromatic sense is needed ; or the mortifications, &c, arising from constant mistakes of dress &c, in every-day life, — as all these bear no relation to the importance of the danger to life and property on land and sea from this curious visual defect. The railroads of England pay two million dollars a year for killed and injured travellers.

I must explain some expressions in my text. I always use the term color-blindness, instead of Daltonism, as more truthfully representing the defect in general, as Dalton was red-blind ; and also in order not to continue to attach this defect to his name. This has become pretty universal, except with the French, who, having no one word for color-blindness, still say Daltonisme for brevity's sake. My speaking of a color-blind I would apologize for by saying, were I to have added " person " each time, my readers would, I think, have preferred the present bad grammar.

I am quite aware, that, instead of presenting the material of this volume in its present shape, I could have given a condensed essay on color-blindness more easily read ; but such a book would not meet the wants of the immediate future. The question of color-blindness is soon coming up in a very practical form in this coun-

PREFACE.

XL try. Those who have to deal with it will property ask for the original material which they may themselves study, and which I have here collected. Such material, as my bibliography shows, is widely scattered and in foreign languages ; whilst other I here present has never been published. For this reason I risk the natural criticism my work will call forth, rather than fail to give full opportunity for those who from their position must hereafter have my gathered material within their reach.

As this volume is intended to meet the wants of several quite different classes in the community, its contents are somewhat varied. Many of the chapters may be read by themselves, by those who are only interested in the subject from the point of view touched on in that special chapter. General readers will find the historical cases, and the curious mistakes caused by this chromatic defect, of most interest to them perhaps. Physicians will be interested in facts relating to color-blindness from disease, its heredity, and the supposed peculiarities heretofore connected with it, as also its incurability. Scientists and plrysiologists will naturally turn to the accounts of the precise condition of color-blindness and its relation to normal color-sense, as well as the additional methods of detection. The color-blind cannot but be interested in the palliatives of congenital color-blindness, since we can now do more for them than formerly. The dangers on land and sea concern us all. Railroad authorities will find full explanation of the precise condition of their color-blind employes. The possible change of railroad and marine signals will also concern them and the officers of the navy and mercantile marine. The possibilit}' of detecting and eliminating the color-blind is important to those whose position requires them to avoid employing such. The methods xii

PREFACE.

of so doing interest the specialists employed for this purpose. Our national and state legislatures and railroad commissioners will naturally turn to the account of the present provisional European laws in reference to the control of color-blindness on land and sea.

I have hitherto avoided seeking for the color-blind, and discouraged those who I understood would apply to me ; because I desired to have my statistics as near as possible precisely represent the truth as to the prevalence of this chromatic defect. My present numbers are so large as to perfectly decide, for nryself at least, this point. I therefore am now anxious to hear from the color-blind, by letter or otherwise, as each and every account is of value. The personal observations of any who have this defect would interest me, and be of service to science. All names would of course be strictly confidential. I am at present devoting special attention to the question of heredity, and naturally very anxious to hear from any one on this point. In many color-blind families the facts must be pretty well known as to the different members, and such I desire to have causa sciential. My professional brethren may be able to assist me in this, and I would hereby ask it of them. I well know that man} r color-blind persons, whilst shrinking from exhibiting their defect, would not hesitate to give an account of their case when assured their names would not be used.

The dedication of this volume, and the free use I have made of his material, show how much I am indebted to Professor Holmgren of Upsala, Sweden, with whom I have been in constant communication. I have also to greatly thank Professor Donders of Utrecht for advice and suggestions, as well as for the rules of the Holland railroads. I am indebted for information and

PREFACE.

xiii numerous publications to the following gentlemen, whom I would hereby gratefully remember : Dr. Magnus of Breslau, Drs. Eulenberg and Hirschberg of Berlin, Dr. Stilling of Cassel, Dr. Cohn of Breslau, Dr. Zehender of Rostock, Dr. Schiess of Basle, Dr. Warlomont of Brussels, Professor Delbceuf of Lille, Drs. Favre and Dor of Lyons, Dr. Nicati of Marseilles, Dr. Quaglino of Pavia, Dr. Daae of Kragero, Norway, and Dr. Hjort of Christiana, Norway, Dr. A. von Reuss of Vienna, Dr. Robertson of Edinburgh, Dr. Bruno Kolbe of St. Petersburg, Professor Horner of Zurich, Dr. Meyer of Florence, Dr. Ncctoliczka of Gratz, Dr. Hosch of Basle, Dr. Gintl of Vienna, Dr. de Fontenay and Dr. Krenchel of Copenhagen, Dr. Brailey of London, Mr. William Pole of London, Dr. Bouvin of Utrecht, Dr. Marechal of Brest, surgeon-general United States Army, surgeon-general United States Navy, surgeon-general United States marine-hospital service, Mr. Dunning of "The Railroad Gazette," Mr. Willard A. Smith of " The Chicago Railway Review," and the many gentlemen who have sent me their unpublished or published statistics, &c.

To the Boston School Board my thanks are specially due for permission to test the scholars of the public schools.

To avoid' cumbering this volume with references, I use an author's name, and the bibliography will enable the reader to turn to the original. There is, I believe, no excuse for a writer not giving his best work to the public ; but I must add here, that the time for my thirty-four thousand examinations for color-blindness, and the preparation of this volume, has been stolen from the busy hours of a professional life.

B. Joy Jeffries, M.D.

15 Chestnut Street, Beacon Hill, Boston.

Introduction

There are some points in reference to color-perception which I must first explain to my unprofessiona/ readers, to show what color-blindness is not. Our point of best vision on the retina is directly in the centre, and over but a small space here ; so that, to see an object distinctly, we must carefully turn the eye, to keep the picture on this portion. In looking at a long word on a page, we unconsciously travel along it to catch all the letters. If we keep our eye fixed on one point, and move a letter awa}^ from this point, its form is soon lost, and we fail to recognize it. In other words, if the image of the letter falls on the retina but a little way from the centre, called "the yellow spot" from its color, it is confused. Form-perception diminishes very rapidly from the centre outwards in all directions. Now, this is also the case in reference to color. Let one e}-e be closed, and the other fixed on a bright-red object, like a wafer, held before it. When moved gradually out from the central field of vision, the wafer will decrease in brightness, and finally appear black. Its form we may still discern. This is not color-blindness. A painter has added a bright little scarlet flower

XV xvi

INTEODUCTION.

down in one corner of his picture, and turns to work in the centre, when suddenly the scarlet flower loses its color, because its image falls far away on the retina from the point of best color-perception. This same will be found in reference to the other primary colors in varying degrees.

Another point : Whenever the retina is tired out with one color, it can only perceive the complementary one. If with one e3 r e we gaze steadily for some seconds at a bright-green disk on a white ground, and then quickly look at another white surface, we shall see a red disk. Gazing fixedly at the setting sun when a deep red, and turning quickly to the east, we shall see a rising green sun. I hardly need say this also is not color-blindness.

Again : the crystalline lens in the eye becomes, with age, harder, and of a yellowish color, — up to positive blackness. When opaque, it prevents, of course, the passage of light through the pupil : it is called cataract. This opaque lens we then remove from the eye, and replace it by a strong convex lens in the spectacles. Whilst the lens has been turning } T ellow, all the person's light has been yellow ; so that, when the lens is removed, the impression will be that of the complementary color, — bluish. Many old persons whom I have operated on for cataract, after it was removed, and they were able to use their sight, complained that every thing was blue ; that, for instance, their children's faces appeared blue : and the}^ naturally often expressed considerable disappointment that life was to be to them wholly bluish. This is not true color-blindness, and soon wears off. Santonine, or worm-seed, causes, when taken, all objects to appear a bright yellow, or sometimes its complementary color, violet..

INTRODUCTION.

xvii

The effect is not permanent, and passes off in a few hours.

Another physiological fact in relation to color-perception is very important, and seems to be generally quite unknown or neglected. Around the point of best vision in the centre of the retina is a zone where we perceive all of the three so-called base colors, — red, green, and violet. Outside of this there is another zone, in which we have a perception of only two ; namely, green and violet ; and again, bejxmd this, on the retina, only blue or violet is perceived. We shall hereafter see how these zones resemble color-blindness.

ITS DANGERS AND ITS DETECTION.

Chapter I. Historical Cases Of Color-blindness

There seems no good reason to doubt that color-blindness has existed at all times in man. It is therefore certainly very curious that its detection, and consequent mention in literature, is so very recent. A case of Dr. Tuberville's (1684) has been quoted and referred to as one of color-blindness. In a letter to the Royal Society, London, Aug. 4, 1684, he says, "A maid two and twenty years old came to me from Banbury, who could see very well, but no color beside black and white. She had such scintillations by night (with the appearances of bulls, bears, &c.) as terrified her very much. She could see to read sometimes in the greatest darkness for almost a quarter of an hour."

This is too indefinite to be admitted as a case of color-blindness recognized at that date. We probably shall hunt literature in vain for mention of color-blindness till nearly a hundred years later,

l when we come (in 1777) to Mr. Huddart's account of the shoemaker Harris of Maryport, in Cumberland, Eng. This case is historic, and the description perfect in its way, rendering it quite worthy of being given here in full. Hucldart writes to Rev. J. Priestley, —

" I have known Harris ten years, and had frequent opportunities of conversing with him. I had often heard from others that he could discern the form and magnitude of all objects very distinctly, but could not distinguish colors. This report having excited my curiosity, I conversed with him frequently on the subject. The account he gave was this : that he had reason to believe other persons saw something in objects which he could not see ; that their language seemed to mark qualities with confidence and precision which he could only guess at with hesitation, and frequently with error. His first suspicion of this arose when he was about four years old. Having by accident found in the street a child's stocking, he carried it to a neighboring house to inquire for the owner. He observed the people called it a red stocking, though he did not understand why they gave it that denomination, as he himself thought it completely described by being called a stocking. The circumstance, however, remained in his memory, and, together with subsequent observations, led him to the knowledge of his defect. As the idea of color is among the first that enters the mind, it may perhaps seem extraordinary that he did not observe his want of it still earlier. This, however, may in some measure be accounted for from the circumstance of his family being Quakers, among whom a geneial uniformity of colors is known to prevail. He observed, also, that, when young, other children could discern cherries on a tree by some pretended difference of color, though he could only distinguish them from the leaves by their difference of size and shape. He observed, also, that, by means of this difference of color, they could see the cherries at a greater distance than he could, though he could see other objects at as great distance as they; that is, where the sight was not assisted by the color. Large objects he could see as well as

ITS DANGERS AND ITS DETECTION.

other persons ; and even the smaller ones, if they were not enveloped in other things, as in the case of cherries among the leaves. I believe he could never do more than guess the name of any color; yet he could distinguish white from black, or black from any light or bright color. Dove or straw color he called white, and different colors he frequently called by the same name ; yet he could discern a difference between them when placed together. In general, colors of an equal degree of brightness, however they might otherwise differ, he frequently confounded together ; yet a striped ribbon he could distinguish from a plain one, but he could not tell what the colors were with any tolerable exactness. Dark colors in general he often mistook for black, but never imagined white to be a dark color, nor dark to be a white color. He was an intelligent man, and very desirous of understanding the nature of light and colors, for which end he had attended a course of lectures in natural philosophy. He had two brothers in the same circumstances as to sight, and two other brothers and sisters, who, as well as their parents, had nothing of this defect. One brother is master of a trading-vessel. I met him, and asked him whether he had ever seen a rainbow. He replied he had often, and could distinguish the different colors ; meaning only that it was composed of different colors, for he could not tell what they were. A piece of ribbon he without difficulty pronounced striped, and not plain. The several stripes of white he uniformly so called. The four black stripes he was deceived in ; for three of them he thought brown, though they were exactly of the same shade with the other, which he properly called black. The light green he called yellow, but he was not very positive. He said, ' I think that is what you call yellow.' The middle stripe, which had a slight tinge of red, he called a sort of blue. But he was most of all deceived by the orange color : of this he spoke very confidently, saying, 'This is the color of grass: this is green.' I also showed him a great variety of ribbons, the color of which he sometimes named rightly, and sometimes as differently as possible from the true colors. These experiments were made in the daytime, and in a good light. I asked him whether he imagined it possible for all the various colors he saw to be mere difference of light and i shade ; whether he thought they could be various degrees between white and black, and that all colors could be composed of these two mixtures only. With some hesitation he replied, No : he did imagine there was some other difference."

In 1779 Mr. J. Scott reported his own case in a letter to Rev. Mr. Whisson, Trinity College, and communicated by the Rev. Michael Lort. He says that a full red and full green, pale blue and pink, deep red and blue gave him the same sensation ; but he readily distinguished yellow and deep blue. The claret color of a garment seemed to him deep black.

We must again seek in vain in literature for cases of color-blindness till we come, in 1794, to the English chemist Dalton's description of his own vision. His report excited so much attention, that his name became attached to this chromatic defect, which, by general consent, is now among nearly all nations called color-blindness, not only from a desire not to connect so distinguished a man's name as Dalton with a physical defect, but as also being nearer the truth, since only the red-blind are Daltonians. Dalton's case is as interesting as historical. He says, —

"It has been observed that our ideas of colors, sounds, tastes, &c, excited by the same object, may be very different in themselves without our being aware of it, and that we may nevertheless converse intelligibly concerning such objects as if we were certain the impressions made by them on our minds were exactly similar. It will, however, scarcely be supposed that any two objects, which are every day before us, should appear hardly distinguishable to one person, and very different to another, without the circumstance immediately suggesting a difference in their faculties of vision ; yet guch is the fact, not only with regard to myself, but to many others also. Notwithstanding the occasional study of botany, I was never convinced of a peculiarity in my vision till I accidentally observed the color of the flower Geranium zonale by candle-light in 1792. The flower was pink, but it appeared to me almost an exact sky-blue by day. In candle-light, however, it was astonishingly changed, not having then any blue in it, but being what I called red, — a color ■which forms a striking contrast to blue. Friends, when asked, all agreed that the color was not materially different from what it was by daylight, except my brother, who saw it in the same light as myself. Two years afterwards I commenced an investigation of the subject, assisted by a friend. My observation began with the solar spectrum, or colored image of the sun, exhibited in a dark room by means of a glass prism. I found that persons in general distinguish six kinds of color in the solar image ; namely, red, orange, yellow, green, blue, purple. To me it is quite otherwise : I see only two, or at most three, distinctions. These I should call yellow and blue, or yellow, blue, and purple. My yellow comprehends the red, orange, yellow, and green of others ; and my blue and purple coincide with theirs. That part of the image which others call red appears to me little more than a shade, or defect of light ; after that, the orange, yellow, and green seem one color, which descends pretty uniformly from an intense to a rare yellow, making what I should call different shades of yellow. The difference between the green part and the blue part is very striking to my eye : they seem to be strongly contrasted. That between the blue and purple is much less so. The purple appears to be blue much darkened and condensed."

The next cases reported in order of time are by Dr. Nicholl, 1816 and 1818. One was a boy eleven years old, who was color-blind, like Dalton. The other was a man aged forty-nine, who reported thus : —

" The color I am most at a loss with is green ; and, in attempting to distinguish it from red, it is nearly guesswork. Scarlet in most cases I can distinguish, but a dark bottle-green I could not, with any certainty, from brown.

Light yellow I know; dark yellow I might confound with light brown, though in most cases, I think, I should know them from red. The different shades of red and green, I know not to which they belong ; but, when they are before me, I see a difference in the shade. Though I see different shades in looking at a rainbow, I should say it was a mixture of yellow and blue, — yellow in the centre, and blue towards the edges."

These cases are about all which may be properly considered historic. I have referred to the original accounts, and quoted from them. It may be noticed that mention of what the several persons called colors — i.e., the names they gave them on presentation — has been generally omitted. The reason of this will be seen later. It need only here be remarked, that asking the examined to name colors is in reality no test of their color-perception ; and, where this alone has been done, their color-blindness cannot be accepted as proved.

ITS DAGGERS AND ITS DETECTION. 7

Chapter II. Color-blind Mistakes

It will be interesting to note what mistakes their chromatic deficiency causes the color-blind to make, and therefore well worth our while to listen to their own report, as well as that of their examiners. Not only shall we find it curious and interesting, but from a long series of cases we may able to deduce, as has been done, some general laws and classification of this peculiar visual condition. Commencing with the cases I have referred to as historical : Dalton said the color of a florid complexion seemed dull, opaque, blackish blue upon a white ground. Diluted black ink on white paper gives a color much resembling a florid complexion. It has no resemblance to the color of blood. Blood appeared not unlike that color called bottle-green. Grass appeared a very little different from red. The face of a laurel-leaf is a good match to a stick of red sealing-wax, and the back of the leaf answers to the lighter red of wafers. Green woollen cloth — such as is used to cover tables — appeared a dull brownish-red color. A mixture of two parts mud and one red would come near it. It resembled a red soil just turned up by the plough. "When this kind of cloth loses its color, as other people say, and turns yellow, then it appears to me a pleasant green. Very lightgreen paper, silk, &c, is white to me." Blue was the same to him as to other people, both by daylight and candle-light. " Colors appear to me much the same by moonlight as they do by candle-light. By lightning and the electric light they appear as by daylight. A light-drab woollen cloth seems to resemble a light green by day. My idea of brown I obtain from a piece of white paper heated almost to ignition. This color by daylight seems to have a great affinity to green. Browns seem to me very diversified : some I should call red. Dark-brown woollen cloth I should call black."