A case of vivid after-images explained on Hering's theory / by David Fraser Harris.

  • Fraser-Harris, David Fraser, 1867-1937.
Date:
1900
Catalogue details

Licence: In copyright

Credit: A case of vivid after-images explained on Hering's theory / by David Fraser Harris. Source: Wellcome Collection.

Provider: This material has been provided by The University of Glasgow Library. The original may be consulted at The University of Glasgow Library.

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    The first effect is that of a rose-pink patch from the kataboUsm of the li.-G. Sb. by the orange rays, vn-tually a positive after-effect due to retino-cerebral functional inertia. It is pink and not a pure or saturated red because, ex- hypothesi, there is always some concomitant katabolism of the W.-B. Sb. along with any effect due to coloured rays. As soon, however, as the metabolic equilibrium of the R-G. Sb. has been re-established, a yellow patch is per- ceived due to the predominance of katabolism over ana- bolism in the Y.-B. Sb. We have experimental evidence^ that, as studied under appropriate conditions, the sensation of red is elicited in a shorter time than that of gi'een, and still more so than that of violet; in other words, yellow takes a longer time to be developed than red. Thus, as the red sensation passes off, the yellow is reach- ing its maximum,^ the katabohc phase in the Y.-B. Sb. long out-living tbe period of action of the stimulus which pro- duced the disturbance. The yellow is now the only chro- matic sensation not neutralised, and it is perceived in its fulness until, on the metabolic equilibrium being re-estab- lished, it, too, fades away, and the retina recovers from its state of over-stimulation. Neurypnologtj, or the Bationale of Nervous Sleep, considered in Relation to Animal Magnetism or Mesm.erism and Illustrated by Numerous Gases of its Successful Applica- tion in the Belief and Cure of Disease. By James Braid, M.E.C.S., C.M.W.S., &c. A new edition, edited with an introduction, biographical and bibliographical, embodying the author's later views and further evidence on the subject, by Arthur Edward Waitb. London, George Eedway. 1899. The above work comprises (1) a biographical introduction, which gives a short account of Braid's life and a more extended one of his writings; (2) a reproduction of the original edition of Neurypnology, which forms the greater part of the volume; (3) an appendix of editorial notes chiefly drawn from Braid's later works; and (4) a bibliography of Braid's writings. According to Mr. Waite, little is known about Braid in this country, and there is no trustworthy bibliography of his writings, ' Stewart, P.B.S.E., 1888, p. 441, - It has a slightly greater degree of fuuctioual inorfciii.