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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    true name of the colors, even when shown one flag after the other. From this we see how the color-blind railroad employd has learned to distinguish the flags. “ But, after all, what have they learned, and what, strictly speaking, have they gained, by such recognitions? If we ask a color-blind per- son who is intelligent and honest, and who has no interest in concealing his fault, he will openly admit that he has no idea of the color itself, but that he notices a sensible difference in that the green flag is darker to his eye than the red. At the next trial he will make the same mis- take if the first flag is shown him alone, and will be as surely correct if the two are shown together. A railroad employd who daily sees the two flags will not in general make this mistake when the test is repeated ; we readily understand why. The color-blind has learned to apply the names, guiding himself by the difference in the intensity of the light. But he still continues destitute of any idea of color. Ide is always color-blind, and has simply learned an artifice. “ If Dr. Favre’s claim that the railroad and marine personnel should, be trained and exercised in telling colors is formally entertained, it can but lead to admitting the color-blind to positions in question ; and, more- over, in the assurance that their congenital defect can be cured by the performance of their duty, the necessary training is looked out for. Such advice, we think, is positively dangerous, as it only deceives the authorities into the idea that the color-blind can cause no accident; whilst in reality their defect is where it was before, and, moreover, from this training becomes more difficult, I may say impossible, to discover, if a faulty method of testing is employed. In this point of view the training, far from averting, only increases the danger.” I think the necessity of discussing as far as I have what at first sight seemed perhaps only a medical opinion has now been made apparent. The very mistake Dr. Favre has been led into has also deceived rail- road officials, who here and there have tested an employd suspected of color-blindness with the flags or lanterns used on their individual roads. It requires considerable argument and positive proof to convince a rail- road superintendent that one of his men whom he has had cause to suspect, and has seemingly thoroughly tested, is after all color-blind. It is very difficult for him not to believe his employd has learned, or can be made to learn, to see colors as they appear to a normal eye. He, however, will be convinced against his reason, when the color-blind man is in his presence subjected to a proper scientific test applied by a competent specialist.