Incurability of congenital color-blindness / by B. Joy Jeffries.

  • Jeffries, B. Joy (Benjamin Joy), 1833-1915.
Date:
[1878]
Catalogue details

Licence: Public Domain Mark

Credit: Incurability of congenital color-blindness / by B. Joy Jeffries. Source: Wellcome Collection.

Provider: This material has been provided by The Royal College of Surgeons of England. The original may be consulted at The Royal College of Surgeons of England.

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    undoubtedly prove it. Professor Helmholz, in his Physiological Optics (page 299, 1867), said, “ As to the examination of the color-blind, simply asking them to name this or that color will naturally elicit but very little, since they are then forced to apply the system of names adapted to normal perception to their own perception, for which it is not adapted. It is not only not adapted because it contains too many names, but in the series of spectral colors we designate differences of tone as such, which to the color-blind are only variations of saturation or luminosity. It is more than doubtful whether what they call yellow and blue correspond to our yellow and blue.” The lack of practical value of tests for color-blindness which require the examined to name colors has been well shown these last two years in the search for defective color perception amongst the personnel of the armies, navies, and railroads of Europe. It seems strange that Dr. Favre should have been led to conclude that color-blindness was so frequent as thirty or forty per cent., or that it was curable by exercise with colors, since his experience with railroad employes has been very large. He probably was deceived by using with these latter tests call- ing only for the naming of colors. At first sight it seems only natural that we should be able to improve our color perception by use, as we may sharpen our other senses by ex- ercise. But in the color-blind there is a congenital defect or deficiency. With the ear we may learn to distinguish sounds whose vibrations come within the range of our scale, but no amount of instruction can make us hear a note above or below the vibratory scale of our ear. A lit- tle practice will enable the normal eye to discriminate between the lighter shades of green and blue, which at first it had confounded, but no amount of exercise with colors can cause the color-blind eye to per- ceive those colors as we do, to whose ethereal wave lengths or numbers it is not adapted. However much practice may cultivate the power of an organ, it can never give that organ a different or additional power. I admit that constant exercise may enable a person only partially color- blind to improve his capacity for discriminating colors, but even then I do not believe he has altered his color perception, but only supplemented it by additional means, as we so often see other senses, when deficient, supplemented. Whether we shall ever be able to cure color-blindness is another question I am not in position to decide. I desire here only to state my belief, shared in at present by all physiologists and ophthal- mic surgeons, that it has not been and cannot be cured by exercise with colors. From Dr. Favre’s valuable researches, and his well-known and recognized connection with the present great advance in the testing for color-blindness amongst railroad employes and elsewhere, his belief in the curability of this defect might have undue weight. It must be remembered that he stands alone in this. I have therefore endeavored to show how and why he was mistaken, as others also midit well be.