Colour perception and other visual functions in their practical aspects / by Freeland Fergus.

  • Fergus, A. Freeland (Andrew Freeland), 1858-1932.
Date:
[1910?]
Catalogue details

Licence: In copyright

Credit: Colour perception and other visual functions in their practical aspects / by Freeland Fergus. Source: Wellcome Collection.

    1/16
    R&pt'inted from the “ Glasgow Medical JournalJune, 1910.] COLOUR PERCEPTION AND OTHER VISUAL FUNCTIONS IN THEIR PRACTICAL ASPECTS. By FREELAND FERGUS, M.D., F.R.F.P.S.G., Surgeon, Glasgow Eye Infirmary. The editors of the Glasgow Medical Journal have done me the courtesy of inviting me to write a short communication on the important subject of colour-blindness, particularly in its practical aspects. I have gladly availed myself of their invitation, because it affords me an opportunity of reviewing for my own benefit, and I trust also for the profit of the readers of the Journal, a controversy in which to some extent I may be said fifteen years ago to have led an all but forlorn hope. Time, however, has been on the side of truth, and to-day the Board of Trade will have to reconsider the whole of their regulations concerning colour testing. My interest in the subject of colour perception was first aroused when I was a post-graduate student in the laboratory of Donders. He was at that time engaged in an endeavour to prove the truth of the Young-Helmholtz theory of colour vision, and a great part of my time was spent in conducting experiments under his direction and in amassing a con¬ siderable amount of statistical information. The instrument which he employed was a differential spectroscope; each collimator was fitted with a Helmholtz diaphragm, so that the amount of light admitted to each spectrum could be decreased or augmented at pleasure. By this arrangement the luminosity of the two spectra could be altered. Thus, it was possible to make any portion of the lower spectrum of about the same degree of luminosity as another portion of the upper one, so that the element of the difference of luminosity was largely eliminated. When these precautions were adopted, it was found that