Most Prevalent Amongst Jews and Quakers Four men in every hundred, and one woman in every two hundred, are colour-blind, Professor Henri M. Leon told the Colour Circle of the International College of Chromatics recently. This abnormal want of vision is more prevalent amongst the Quakers and the East End Jews than any other class, possibly because, it was suggested, in the case of the Quakers the original members of the sect were strongly opposed to brilliant colours, and in that of the poorer Jews generations have had to live in ghettos, narrow streets, dark rooms, and soon. The fact, too, of its greater prevalence amongst men than women may be due to the constant use of colours by the female, which may have had a tendency to prevent her from being colour-blind to the some extent as men.
Colour-blindness is now generally divided into three kinds: the first total, when persons cannot distinguish colours at all; the second partial, when they can discern certain colours, but confuse red with green, black, and brown; and the third, also partial, but in a lesser degree, when persons are unable to distinguish shades and confuse, for example, blue with violet.
Dr. John Dalton, a Quaker, presenting a pair of brilliant rod stockings to his mother, and choosing at his tailor's a bright red cloth specially designed for hunting jackets; a captain in the Navy ordering a pair of trousers to be out from red cloth, and remaining in ignorance of the true colour until] he wore them on deck one day and heard the guffaws of his officers and a house painter painting the exterrer of a house a vivid blue instead of grey, were mentioned by Dr. Leon as examples of the amazing mistakes due to colour-blindness. He recalled also the trial of the Eastbourne tragedy when three witnesses called to prove the identity of one of the prisoners stated variously that he was wearing blue, grey, greeny-blue. The judge, he said. did not seem to think of colour-blindness, but asked the jury to look at the wall opposite and say whether it was grey, blue, or bluey-green, and they were unable to agree.
For those forms of colour-blindness that had been inherited there is, it was declared, no cure. But those that are due to excessive alcoholism ('Blue devils"), drug taking, and smoking, are tempora ary, and may be removed by gtopping the cause.
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