Color-blindness : its dangers and its detection / by B. Joy Jeffries.

  • Benjamin Joy Jeffries
Date:
1879
Catalogue details

Licence: Public Domain Mark

Credit: Color-blindness : its dangers and its detection / by B. Joy Jeffries. Source: Wellcome Collection.

    162/346 (page 134)
    In all cases there can be attached to the engme an ap- paratus which prevents even the most color-blind from pos- sibly confounding red or green with any color, and which would add to the contrast of tho signals. The apparatus would consist of a red and a green glass having the proper- ties spoken of. When the engineer had the slightest doubt, he need but look through these glasses. Looking through the red, the signal of that color would become brighter, and contrast more with the general visual field. On the other hand, it would be weakened by looking through the green. Tho reverse holds true of the green signal. This apparatus, infallible for the day-signals, would be efficacious to a cer- tain degree for the night-signals also, but perhaps less prac- tical here. On this point Dr. Magnus says, — « Whether the method, lately proposed by Professor Del- bceuf, of palliating or improving color-blindness by fuchsine- colored glasses, will prove of service, time must decide. Pro- fessor Delboeuf, himself color-blind, believes the method of practical value, as tested in his own case. But, as we have already pointed out, deception here is very possible; and one may readily mistake for a cure of color-blindness the practice which a color-blind has gained by any increased sensitive- ness to shades of light in distinguishing colors. ]\Ioreover, there has as yet been no practical experience with Delboeuf's method. In order to fairly test Professor Delboeuf's sup- posed remedy or cure of color-blindness, I have had the apparatus made as he directs in his origi- nal article. With the fuchsine solution I have pretty carefully tested six color-blind, both red and green blind, and of various degrees. Two of these were physicians, who had not only paid a good deal of attention to the subject, but also to their own cases. The result was quite unsatisfac- tory. A red-blind, after carefully working with the fuchsine solution, reported that he could obtain