ACCIDENTS BY RAIL AND SEA. 1G7 



theoretically or practically, we maintain that not one ijositive proof of it 

 has so far been produced. 



It is a significant fact that individuals who have themselves discov- 

 ered their own chromatic blindness, and have been very much interested 

 in it, having reflected and experimented, and consequently exercised 

 themselves much in colors, have nevertheless retained their anomalous 

 perception, such as it was in the beginning, for many years, indeed, as 

 long as they lived. Such was the case with Harris, who himself discov- 

 ered his defect at the age of four years, and studied it with much inter- 

 est, but never succeeded in correcting it. Milne was found by Wilson to 

 be as color-blind at Edinburgh in 1854 as he was thirty years before, 

 when Combe examined him. Such was also the case with Professor 



N , examined twenty years before by Sir David Brewster. But 



such was especially Daltou's case, who has thrown much light upon 

 the subject. No one will deny that if exercise in colors can cure chro- 

 matic blindness, Dalton would have been cured, and yet it must be ac- 

 knowledged that at the meeting of the British Association at Oxford 

 in 1832 he then compared a scarlet red to the leaves of trees, proving him 

 to be as colorblind as in 1792, the date of the discovery of his color- 

 blindness, and as far as his friends could observe he continued so to 

 the end of his life (1844). 



The history of science tells us of cases of persons completely blind who 

 can easily and correctly distinguish wool of different colors by means of 

 other senses, smell, taste, or touch. The power of touch in this case 

 deserves especial attention, as it is exactly adapted to the kind of quali- 

 ties now interesting us. The close connection between touch and sight 

 in determining whether an object is smooth, rough, etc., is well known. 

 The assistance which these two senses render each other in a gen- 

 eral appreciation of everything in si^ace is not less well known. 

 These are the very qualities, beyond any doubt, that the color-blind call 

 to their aid to supply the place of colors. This is why many color-blind 

 are seen placing the samples of wool in different lights, bringing them 

 quite close to the eye and in different angles to the visual axis. But 

 we have heard many color-blind, who knew the difference between red 

 and green, or purple and green, frankly acknowledge that they only 

 recognized them because one colored wool was coarser, harsher, or 

 rougher than the other. Consequently it is not the color, that is, the 

 quality of the reflected light, but the coloring matter and its peculiar 

 effects upon the wool, which were to them the distinguishing features. 

 As the result of our investigation we can state that exercise is certainly 

 not without value, but is more useful in other respects than in curing 

 color-blindness, or in removing the causes of the mistakes made by the 

 color-blind with regard to the colors of signals. We maintain, therefore, 

 that not one case has been sufficiently established to prove that a genuine 

 case of color-blindness has ever been cured by exercise. 



But it in no wise follows, we repeat, that we deny the possibility of 



