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XXII. — On the Present State of Knowledge and Opinion in regard to Colour- Blindness. 

 By William Pole, F.R.S., F.R.S.E., Mus. Doc. Oxou., Honorary Secretary of 

 the Institution of Civil Engineers. (With a Plate.) 



(Read January 16, 1893.) 



At the meeting of the British Association in Edinburgh, in August 1892, the President 

 of the Biological Section, Professor W. Rutherford, M.D., F.R.S., F.R.S.E., gave an able 

 opening address on " The Colour-Sense," in which he took occasion to speak at some 

 length on that remarkable defect of vision called Colour- Blindness. After alluding to the 

 large share of public attention it had lately attracted, both on scientific and popular 

 grounds, he pointed out the unsatisfactory nature of certain statements lately put for- 

 ward, and gave good reasons why the views still largely held on it in this country required 

 revision. 



There can be no doubt that the unfavourable comparison made between the state of 

 knowledge here and that prevailing in foreign scientific circles is well founded. The views 

 held in England seem to be essentially the same as they were a quarter of a century ago, 

 after Clerk Maxwell had so energetically revived Young's Theory of Colours. But 

 since that time the knowledge of facts, and the views of their explanation, have much 

 advanced. The subject of colour-blindness has been industriously studied and discussed 

 by some of the most powerful minds in Europe ; it has been illustrated by elaborate 

 investigations and able reasonings ; and a great mass of matter has been written upon it 

 by eminent authorities — physicists, physiologists, and specialists — well qualified to deal 

 with the matter. Hence it would certainly seem that if the knowledge thus gained were 

 duly taken advantage of, much of the obscurity in which the facts appear to be veiled 

 might be cleared away. 



I have therefore thought that the indications given at the British Association meeting 

 might with advantage be expanded, and carried out further ; and since this is a matter to 

 which I have devoted much attention, I venture to offer an attempt in that direction. 



It will be perceived that I only touch on a small fraction of Professor Rutherford's 

 learned address. That comprehended profound remarks on our sensory impressions gene- 

 rally, followed by a still more elaborate discussion of the sense of colour. I do not venture 

 into these regions ; it would be presumptuous for me to discuss or argue upon the theories 

 of colour- vision generally, which I leave to those better qualified. I confine myself to 

 the phenomena of colour-blindness ; and in speaking of them, though I cannot exclude 

 the mention of theories (which have, indeed, become inseparable from the subject), I need 

 only meddle with them so far as they interfere immediately with the understanding of 

 these phenomena. 



VOL. XXXVII. PART II. (NO. 22). 3 Y 



