

1905. | Two Cases of Trichromic Vision. 197 
Colour Mixtures—He was then tested with Rayleigh’s apparatus. On 
being shown my match he said that the yellow was green and the mixed 
colour salmon pink. He said that the yellow of my match was too dark, 
and in order to make a match, as far as luminosity was concerned, he had 
to increase the brightness of the yellow. No match was then possible to me. 
He made the following 10 matches :— 
Match. Difference. 
*1. 15°66 —0°815 
Tole O +0°525 
T3. 16°90 + 0°425 
*4. 16°33 —0°145 
+5. 17-40 +0°925 
Difference, Difference, 
Match. Difference. red first. green first. 
t 6. 17:0 + 0°525 — ele +0°425 
et? 160 — 0-475 +0°525 +0°925 
8. 1533 —1:145 — 07145 +0°525 
* 9. 15°80 —0°675 —0°475 —1:145 
710. 17:33 + 0°855 —0°675 + 0°855 
Average, 16°475 Average, 0°651 Average, 0°527 Average, 0°775 
* Red first. + Green first. 
Lantern Test—He called pure yellow “yellow-green” and pure blue 
“blue-green.” Dark blue he called purple. The other colours he named 
correctly. 
Classification Test—I he designated “golden yellow” and matched it 
with orange. II he called “purple” and put with it violets and purples. 
IIT he said was “crimson” and sorted out a few reds to go withit. IV he 
named “blue” and matched with greens and blues. Many colours were 
omitted. He called yellow “yellow-green.” He chose orange-yellow for 
yellow. He found great difficulty with blue and green. Ladies have several 
times told him of mistakes in this respect. On being shown IV (blue-green) 
a second time, he said that it was “pure green without a trace of blue.” 
Simultaneous contrast was very strongly marked. 
I use the term-trichromic as a statement of the fact that persons having 
this vision see only three colours in the bright spectrum, whilst the normal 
sighted see six, and may, therefore, be designated hexachromic. It is 
