On binocular flicker and the correlation of activity of 'corresponding' retinal points / by C. S. Sherrington.

  • Charles Scott Sherrington
Date:
[1904]
Catalogue details

Licence: In copyright

Credit: On binocular flicker and the correlation of activity of 'corresponding' retinal points / by C. S. Sherrington. Source: Wellcome Collection.

Provider: This material has been provided by UCL Library Services. The original may be consulted at UCL (University College London)

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    By ' retinal point' is here understood the retino-cerebral apparatus engaged in elaborating a sensation in response to excitation of a unit of retinal area. In the inquiry much use has been made of flicker as a visual criterion. Almost without exception the experiments have confined themselves to the central (macular) region of the retina^; and the ir]tensity of the physical illumination used has been well above the threshold for the light-adapted eye. Section I. Symmetrical Flicker. Ordinarily when the binocular gaze is directed upon an object intermittently illuminated, successive phases of illumination affect the corresponding areas of the two retinae synchronously. The question rises, will the rate of repetition necessary for visual fusion of the successive light phases be altered if those phases fall upon corresponding retinal points not synchronously but alternately ? To examine this question the following arrangement was devised. A. Method employed. A double shoot of thick inilk-glas.s was observed by transmitted light given by a single-loop incandescent lamp, itself enclosed in a candle-shaped frosted glass. The lamp was fed at rather above its intended voltage, in order to give white qiiaHty of light, by accumulators unused during the experiment for any other purpose, and therefore supplying the lamp in constant measure. The lamp generally used was of 8 candle power, under a 100 volts. This lamp was set verti- cally in the axis of a rotating cylinder. This cylinder of turned brass was 78 mm. in diameter. In its side were cut three horizontal rows of rectangular windows tier above tier. The lamp though fixed in the axis of rotation of this revolving cylindrical screen was entirely free from all attachment to it. The milk-glass plate was fixed between the lamp and the inner face of the tiers of windows close to the latter. Outside the moving cylindrical screen was a fixed semi-cylindrical screen con- centric with the revolving one and just of width enough to allow the inner revolving one to turn within it freely. In the fixed cylindrical screen four circular holes were arranged so that two were centred on the same horizontal line, and of the other two one was centred as far above the left-hand hole of the just mentioned pair as the other was below the right-hand member of the pair. The horizontal distance between the centres of the right and left-hand holes was 9 mm. The diameter of each hole was 8 mm. The vertical distance between the centres of the holes was exactly the same as that between the centres of tiers of the revolving cylindrical ^ The experiments were the subject of a brief communication to the Royal Society's Proceedings, July, 1902, Vol. lxxi. pp. 71—76.