MR. W. POLE ON COLOUR-BLINDNESS. 
337 
their infancy, and is encouraged by their every-day communication v^^ith the world, it is 
much more difficult to get rid of than might be supposed. The sufferer may find him- 
self continually blundering, but he must go through a very rigid self-examination before 
he can trace this to the fact that some of the principal ideas he has all his life held upon 
colour are mere delusions. 
Taking red as an example ; it is in the highest degree natural that persons who are 
continually seeing this colour under the appearance of dark yellow, should imagine that 
the latter sensation (which is certainly very distinct from that of full yellow) is what 
corresponds to the term red, and the notion that they cannot really see red at all is one 
they may have the greatest difficulty in comprehending. Hence the very general asser- 
tion by the colour-hlind that they do see red, an assertion which I think has been far 
more readily accepted than it ought to be *. 
My own experience is very decided on this point. It is only after long and careful 
investigation I have come to the conclusion that my sensations of colour are limited to 
blue and yellow. But before I found this out, that is, for nearly thirty years of my life, 
I fir ml y believed that what I now know to be only differences in tone of one or other of 
these, were different colours, and hence I was in the habit of talking of red, crimson, 
scarlet, green, brown, purple, pink, orange, &c., not of course with the confidence 
of the normal-eyed, but still with a full belief that I saw them. If therefore at that 
time any scientific man had examined me, I should have given him a description of my 
case which I now, after more careful study, know would have been entirely wrong. I 
should have told him, among other incorrect statements, that I saw red objects of a 
full tone, such as vermilion, soldiers’ coats, &c., perfectly well; and I could, if necessary, 
have supported my assertion by naming correctly a great variety of bodies having 
this colour, which indeed I am in the habit of doing every day. It would have been 
inferred, with great appearance of truth, that I was really impressible with the red 
sensation ; but I now see what an erroneous inference this would have been. 
24. Another source of confusion in interpreting the descriptions of the colour-blind, 
is the want of due appreciation of the different sensations that may be produced on 
their minds by modified hues of the same general colour. The normal-eyed person con- 
siders green, for example, as always green, whether it be yellow-green, neutral green, or 
blue-green ; whatever the particular “ shade of green,” as it is called, it still has in his 
eye the distinguishing character of greenness, which cannot he hidden or disguised by 
any predominance of blue or yellow it may contain. But with the colour-blind this 
identifying characteristic of greenness is wanting; and hence several patients, speak- 
ing of green, may, hy each having reference in his own mind to some different hue 
of the colour, describe it in the most contradictory terms. One may say, with perfect 
sincerity, that green appears to him like red, another that it looks yellow, a third blue, 
* Red is a more common colour than dark yellow, and hence the preference, by the colour-blind, of the 
former name for the common sensation. A great variety of bodies are known to be red by habit and asso- 
ciation, and are for this reason often named correctly. 
