196 _ Dr. F. W. Edridge-Green. [Jan. 24, 
He seemed to get very easily fatigued with colours. 
Classification Test.—Called I (orange) “reddish-orange,” and matched it 
with orange and dark yellows. Described ITI (violet) as mauve, and put with 
it violets and purples. Named III (red) correctly, and picked out various 
reds to go withit. 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 considerable 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. 
Lantern 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 » 5892 three times out of four as the 
junction of the red and green, the fourth time 2% 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 \ 4861; when 
shown the green first at ) 4740. There was no shortening of either end of 
the spectrum. 
Difference 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. 
