Tests for Colour-Blindness

Abstract

IN 1890 or 1891 the Royal Society appointed a very strong committee, of which Lord Rayleigh was chairman, and it included, among other “able scientific men”, Lord Kelvin, Sir George Stokes, Sir William Abney, and Prof. Michael Foster, to report on the general subject of colour-vision and on the tests proper to be used in con nection with it. Dr. Edridge-Green gave evidence before this committee, stated fully his objections to Holmgren's test, and displayed the methods which he recommended in lieu thereof. His book was published before he gave evidence; and, as his original objections to the Holmgren test are reprinted verbatim in the 1909 edition, it is fair to suppose that no fresh evidence in support of them has been obtained during the intervening time. Besides hearing many witnesses, the committee carried out an extended series of practical investigations, and on April 28, 1892, it unanimously recommended the Holmgren test for adoption by railway companies, ship-owners, and the Board of Trade. The committee pointed out that variations in the amount of deficiency in colour-perception are numerous, and, “when small, are often difficult to classify”. No one claims for the Holmgren test that it affords a sufficient basis for a minute classification, but it does afford the surest and most convenient means of excluding from certain industries the small number of persons who could not engage in them without danger to the community.