Two cases of trichromic vision / by F.W. Edridge-Green ; (communicated by F.W. Mott).

  • Fredrick William Edridge-Green
Date:
[1905]
Catalogue details

Licence: In copyright

Credit: Two cases of trichromic vision / by F.W. Edridge-Green ; (communicated by F.W. Mott). 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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    He seemed to get very easily fatigued with colours. Classification 7’cs<.—Called T (orange) “reddish-orange,” and matched it with orange and dark yellows. Described II (violet) as mauve, and put with it violets and purples. Named 111 (red) correctly, and picked out various reds to go with it. Called IV (blue-green) “ green,” and matched it with some greens. Only a few colours were selected in each case. On being asked to pick out all the yellows he chose those with orange in them. He regarded orange-yellow as his yellow and rejected pure yellows because he said that they had green in them. He had con.siderable difficulty in matching the colours. In common with the cases I have previously observed, the effects of simultaneous contrast were much more marked than in the normal sighted. Two wools changed colour to him on being contrasted, when no change was evident to me. This was particularly noticeable when one of the contrasted colours was either red, green, or violet, and the other one of the intermediate and adjacent colours. Lantet'n Test.—He correctly named the red, green, and violet with and without the neutral glasses, and saw them at the normal distance. He had difficulty with yellow and blue. He called pure yellow “ greenish-yellow.” It will be noticed that the examination with the spectrum gives a key to the mistakes made. 2. The other case is that of Mr. P. S. Barlow, B.Sc., a research student in the Cavendish Laboratory. He sees three colours in the spectrum— red, green, and violet. The red gradually passes into the green, and red- green would describe this region and green-violet that of the blue. He sees no yellow or blue in the spectrum. When I put the pointer in the yellow he said it was in the green. He gave X 5892 three times out of four as the junction of the red and green, the fourth time X 5950. Both are in the orange-yellow. He selected X 4800 (blue) as the point of union of the green and violet. He was very sensitive to simultaneous contrast. When shown the violet first he put the junction of the green and violet at X 4861; when shown the green first at X 4740. There was no shortening of either end of the spectrum. Bifferetwe of Hue Perception.—He was tested in the same way as Professor Thomson. He also called the orange-yellow patch “yellow-green,” and I had to increase the size of the patch until it was half as large again (X 5889 to X 6052) as that of the normal sighted before a difference was seen. I examined him in the same way with the other colours of the spectrum, and found that in every part he marked out a much larger monochromatic patch than the normal sighted. h 2
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