326 
ME. W. POLE ON COLOL’E-BLINLNESS. 
accounts of similar cases, and have now the advantage of a large fund of information 
collected on the subject, which enables me to analyse and express my sensations in a 
much more complete way than I could have done a few years ago. 
It will be convenient first to describe what I may call the syrnjjtom^s of the malady, or 
the effects it produces on my judgment of colours ; and then to endeavour to trace more 
accurately how these effects arise. 
7. The symptoms of my colour-blindness, as manifested by the en’ors I commit in 
judging of colours, are so varied and heterogeneous in character, that it would be an end- 
less task to follow the usual practice of particularizing the mistakes to which they have 
led me. I therefore prefer stating them in a generalized list, such as it might be sup- 
posed a careful normal-eyed person would prepare, who had been examining me fully, 
and had reduced the result of his observations into the most condensed form. 
Symptoms of Colour-Blindness. 
A. Blue and yellow are always perfectly distinguished, even in their hghtest or 
darkest tones, and are never confounded with each other. 
B. Only these two colours are seen in the spectrum, the blue corresponding to the 
more, and the yellow to the less refrangible rays. The red space is seen as yellow. 
C. Bed is often confounded with black, or more properly grey. 
D. It is also confounded with orange, and (E.) mth yellow. 
F. Also with green. This is the most common symptom of all. 
G. Also with brown, (H.) vrith blue, and (I.) with violet. 
K. Crimson and pink appear to have no relation to the idea of red derived from 
vermilion or a soldier’s coat. 
L. Bed is frequently identified, when of a full tone, and when the hue is scarlet, or 
some other tending towards orange. 
M. Green is a colour most perplexing to the patient, who cannot be said generally to 
manifest any definife sensation about it at all. 
N. It is not only confounded with red, but also with black, white, or grey. 
O. Also with orange; (P.) with yellow; (Q.) with blue; (B.) with 'violet; and (S.) 
with brown. 
T. Orange is confounded with yellow. 
V. Violet is confounded with black or grey, and (W.) with blue. 
X. Light or dark tones of certain colours are more liable to mistake than full tones. 
8. Symptoms such as these, in their apparently hopeless complexity, furnish all the 
information usually obtained from a colour-blind witness under his examination by a 
normal-eyed investigator. I propose, however, now to go further, and to state, in a more 
definite and logical manner, what my sensations of colour really are, and how they may 
be made to explain and reconcile the anomalous effects above alluded to. 
In doing this it is necessary to have some standard specimens to refer to, and the most 
