The seat of vision determined : and, by the discovery of a new function in the organ, a foundation laid for explaining its mechanism and the various phenomena, on principles hitherto unattempted / by Andrew Horn.

  • Horn, Andrew.
Date:
1813
Catalogue details

Licence: Public Domain Mark

Credit: The seat of vision determined : and, by the discovery of a new function in the organ, a foundation laid for explaining its mechanism and the various phenomena, on principles hitherto unattempted / by Andrew Horn. Source: Wellcome Collection.

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

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    the most satisfactory hitherto given. But, unfortunately, the anterior portion * ^ * of the great cavity of the eye presents a configuration ruinous to the theory. It is evident, on the slightest inspection into the internal structure, of the organ, that, although it could be demonstrated that the retina is the true seat of vision, and the anterior the most delicate part of this membrane, still, vision could not be accomplished in the manner supposed by the hypothesis ; for it leaves an ob- scure space where vision is always found most distinct. The image, indeed, which a reflecting telescope exhibits, is not in- jured by the aperture in the centre : this is owing to two causes, first,' to the smallness of the perforation, and then, to the image being produced by caustic rays. The case, however, is very differ- ent, when we suppose the anterior part of the retina impressed by the posterior picture. Thecapsule of the crystalline un- questionably is no propagation of the reti- na, consequently, a large blank is left by the hypothesis, in the centre of the field of