BETIEWS — RESEARCHES ON COLOUfi-BLINDNESS. 119 



' callings much conversant with colour, are uot unfrequently colour- 

 1 bliud. I, myself, have very recently oeeu offered " any reasonable 

 ' fee" if I would cure a worthy working tailor of almost total inabil- 

 ' ity to distinguish colours. I know of cases among haberdashers 

 ' and silk-uiercers ; and on enquiring at one of the latter, who had 

 ' served under a colour-blind master, and thereby had his attention 

 1 directed to the matter, what became of those haberdashers who 

 ' could not distinguish colours, he made the unexpected reply, " that 

 1 they generally ended in mourning- warehouses." ' 



We hud also instances of chemical students unable to tell the 

 colours of their precipitates, and even a chemical professor who 

 hardly dare speak to bis students about the colours of bodies ; of- 

 fice-clerks usiug red and black ink without knowing the difference, 

 and obliged to ask a friend which is the red and which the black 

 sealing-wax. Dalton himself compared red sealing-wax to one side 

 of a laurel leaf, and a red wafer to the other, and his doctor's 

 scarlet gown to the leaves of trees ; and lastly, a house-painter, 

 who could not distinguish any colours but black and white, and who 

 ' trusted to his wife in selecting and mixing colours,' on one occasion 

 painted some square yards of the wall of a public building blue, 

 under the impression that he was producing a stone-tint. 



Our limits do not allow us to follow Dr. Wilson through the 

 many varieties of colour-blindness that he has recorded, but we 

 quote the following as illustrations : 



( Case of Br. Y., described by himself.) 

 " The colours I see in the rainbow are blue and yellow. Crystals examined by 

 polarised light present to my eye the same appearance as to yours — most likely ; 

 that is to say, I see f he yellow and blue, the red and green, and on turning the prism 

 round I see them changing, but I cannot retain in my eye the red and green, and 

 could not tell them on a piece of cloth the next minute. 



11 The colours which I distinguish best on natural objects such as cloths, glass, etc., 

 I think are yellow and blue, the worst are red and green. Yet when I try to ans- 

 wer your two questions, which I must run together, 'What colours are confounded 

 with each other, or supposed identical or undistinguishable?' and 'What mistakes 

 have been made in reference to colours ?' I feel that I may be said not to recognise 

 any colour. In the first place, I never could recognise corn whether it was yellow 

 or green, the green appearing only as a darker shade of yellow. Green and red I 

 cannot distinguish from each other. Red I never saw in the fire, gas, candles, etc., 

 only yellow and blue. Red cabbage growing, pickled, or in infusion, are all the most 

 beautiful blues I can conceive, and it was by not observing any change by acids in 

 the infusions of red cabbage, when attending Professor Hope's chemistry class where 

 I used to stare for the whole hour expecting to see the change, that I first became 

 fully convinced of my gre.it defect. Red, again, in the lips, cheeks, nose, rose9 

 (red), gooseberries, inflammations, and the like, looks blue tome! — (I never saw a 



