REVIEWS — EESEABCHES 0>~ COLOTJ.K-BLINDNESS. 151 



coloured by nitrate of silver, are to my eyes absolutely the same. Yet my eye can 

 appreciate most delicately the various shades of all these colours, but they are all 

 to ma but shades of one colour, and that colour varieties of what I can see in the 

 pure deep sky or in Prussian blue — in fact, blue in various dilutions. Red hot coals 

 and gamboge yellow are to me identical in colour. Intusion of red cabbage deep- 

 ened by alkalies, or reddened by acids, to me exhibits no change of colour, but 

 only a greater intensity cr depth of colourin the acid jar — the actual colour remains 

 absolutely the same. I cannot detect cherries, strawberries, or the red fruits from 

 the leaves but by their form. 



" In purchases I have consequently made many mistakes. For instance, I bought 

 a red dres3 thinking it a green one. I have, on more than one occasiou, bought red 

 and green trousers thinking they were brown, and had to get them dyed afterwards 

 to get them worn. In Paris I bought a red cap to wear instead of a hat, thinking- 

 it a green one; in fact, I could give very many instances of similar mistakes. 



Dr. Wilson adds to this the remark : 



In the preceding explicit account, Dr K. has, in addition to direct statement, 

 supplied an incidental proof of his colour-blindness. He refers to infusion of red 

 cabbage as being deepened in colour by alkalies ; but this infusion, which is origi- 

 nally purple, is not rendered darker by alkalies, but is changed into a bright green. 

 An equally striking, and withal amusing, evidence of inability to distinguish colours 

 is afforded by the chart of prismatic colours to which Dr. K. alludes. He was ad- 

 venturous enough to prepare it himself, and the result may be anticipated ; a youth- 

 ful member of his family soon informed him that one of the spaces was wrongly 

 coloured ; and on asking sight of the chart I found that what was called the violet 

 band was a full crimson, so that both extremities of the prismatic spectrum were 

 represented as red. 



Almost all the cases referred to in this work present; nothing of 

 melancholy in the subjects thereof: never having known the beauty 

 and charm of colour, they do not suffer from the deprivation, and 

 their mistakes are to themselves rather a source of amusement 

 than annoyance ; but one case is mentioned of a gentleman in full 

 possession of his colour-faculty, receiving, by a fall from his horse, 

 a concussion of the brain, which terminated in the permanent loss 

 to him of this power. 



It is painful to read that — 



Whilst formerly a student in Edinburgh, he was known as an excellent anatomist ; 

 now he cannot distinguish an artery from a vein by its tint. He was previously 

 fond of sketching in colours, but since his accident he has laid it aside as a hope- 

 less and unpleasant task. Flowers have lost more than half their beauty for him, 

 and he still recalls the shock which he experienced on first entering his garden after 

 his recovery, at finding that a favourite damask rose, had become in all its parts, 

 petals, leaves, and stem, of one uniform dull colour ; and that variegated flowers, 

 such as carnations, had lost their characteristic tints. 



Alone of all the cases which I have recorded, he knows what he loses by his co- 

 lour-blindness, and is even worse off in some respects than the totally blind; for if 

 they have never witnessed colours, they will not think of these as things they can- 



