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Show ' MANY PERSONS COLOR BLIND Tests Used by Railroads Show That Almost Everybody I Slightly Color Blind. The varloua tenia for color blind-neaa blind-neaa have come Into practical line In , ibe examination of railroad engineers and the like, where the ability to dlrv tlngulnh colore Is necessary, so that these tests are no longer peculiar to the laboratory. Hut It la not generally gener-ally known outside the laboratory that everybody Is partially color blind-that blind-that U, In certain parts of the field of vision. The most normal Individual j can aee all the colore only when lie looks directly at them. If looked at from an angle of about fifteen degrees red and green can no longer be seen, but In their pliiceiTwllI appear shades of yellow or blue. This region of the eyes Is known as the yellow blue gone, If the color be moved still farther to the side the yellow and blue will disappear dis-appear and only gray can be seen "This region Is known bs the gone of tomplete color blindness. An Interesting Inter-esting theory In regard to these zones Is that every normal eye represents three stages of evolution. The gone of complete color blindness Is the lowest low-est stage, and appears In such animals ani-mals as the frog, whose vision Is known as shadow vision. The blue-yellow blue-yellow tone Is one step higher In the scale, although not clearly marked off In the animal kingdom. And the appearance of the red green gone marks the highest stage of evolution. Cases of color blindness are, according accord-ing to this theory, a lack of development develop-ment beyond the early stage of Individual Indi-vidual life Strand Magazine. |