COLOR-BLINDNESS.

South Canterbury Times, Issue 2908, 21 July 1882, Page 2

COLOR-BLINDNESS.

In the year 1790, Mr John Dalton, the principal of a well-known school at Kendal, then about 27 years of age, anf acute and vigorous observer and thinker^.'- j; walked into his garden' and gathered a?; V bunch of geraniums and roses, witli-: “ which he set off into the town. Qn hia way a party of young ladies oompli. mented him on the beauty and brilliancy of his flowers, but were : rather facetious as to their arrangement. “You have got,” they said, “ all the reds and greens so curiously mixed ; and yon a botanist toot" “For my part,” said Mr Dal. ton, “ the whole bunch appears to be pretty much of one color; though some of the leaves which you call light green seem to me rather more like white, while the dark ones would match with a stick of red sealing wax.” Mr Dalton was suffering from' color blindness, then an unknown word, but now beginning to be talked about as something more than a curious and rare infirmity of vision. But the whole question of color blindness opens np to points of wider importance. First color-blindness, it would seem, is not to be regarded as curable, or indeed,, as itself a disease, though possibly a symptom of diseased retina. Dalton’s eyes, after his death, were carefully examined (one actually dissected) for the purpose of ascertaining the cause of his anomalous vision, his idea being that such faulty sight was owing to the fact that one of the humors of his eyes was a colored medium, probably a modifiestion of blue. But the post mortem proved beyond a doubt the fallacy of this theory, the vitreous humors being fooud absolutely free from color. But though opt a positive disease, color-blindness would seem to be widely inherited—four brothers in one family being thus afflicted, of whom, oddly enough; three were cle vor woo d«

engravers, and the fourth still more oddly, a painter in water-colors, which, however, he was obliged to have labelled for him in his daily work. Statistic?, too, however imperfect, clearly prove this much—-that the tendency to color-blindness . may be stayed by good diet and a . healthy exercise of the body, brain, and sight. One more point has yet to bo noted among the statistics of colour-blind-ness ; the singular fact that the three classes most liable to this' anomalous , vision are deaf mutes, Jews, and , Quakers. As regards the first of these, if it bo true that freedom from the calamity depends largely on the perfect and healthy condition of body and brain,-the low status of the deaf mute is at once a sufficient cause. The great majority of deaf mutes belong to a low and debased class, for whom until recent times litt'e has _ been _ done. Scrofula, an inherited disease, is too often the cause of their special calamity, which again they bequeath by close intermarriage to their children, thus famishing more inhabitants for the strange world into which neither sound nor color finds true entrance. Why the descendants of the house Of David—who, as a whole, are deficient neither in power, intelligence, nor culture— should he especial victims of color blitidness, is not so clear. Hut even among them close intermarriages are the rule rather than the exception. With its inevitable fruits. Oat of 9,200 engine drivers, nearly 400 were color blind—i.e., more or less unable to distinguish a green signal from a red One.