On a new membrane in the eye : being the substance of a lecture delivered at Oxford; before the late meeting of the British Association for the Advancement of Science / by George Hunsley Fielding.

Date:
1832
Catalogue details

Licence: Public Domain Mark

Credit: On a new membrane in the eye : being the substance of a lecture delivered at Oxford; before the late meeting of the British Association for the Advancement of Science / by George Hunsley Fielding. Source: Wellcome Collection.

Provider: This material has been provided by the Royal College of Physicians of Edinburgh. The original may be consulted at the Royal College of Physicians of Edinburgh.

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    Pigment a rich black ; in the fox, it is much the same ; in the deer, it is a very pale blue, the Pigment a pale brown ; in the dog it is greenish blue, the Pigment brown. The statement, there- fore, I before quoted, viz.— That ike dark coloured cfioi^oidpaint is wanting, or that it is of a bright reflecting green, or silvery whiteness, in such animals as prowl hij night,^^ is proved to be incorrect by the instances of the cat and the fox. I have never yet found an Eye in which the true Pigment was wanting, excepting in the Albino animal, under which term I include all white animals with red eyes. 7thly—I will now carefully detach a small por- tion of this substance, and place it between two pieces of glass. Tt will be found to present a hard and well defined outline; and on putting the glasses in closer approximation to each other, and then suddenly relaxing them, you will perceive that the substance expands and contracts. This proves that it possesses the property of elasticity. Again, view this portion by reflected light, you will observe its usual colour; but look at it by trans- mitted light, and it will present a totally different one. Neither of these properties belong to any known Pigment j—as regards the last peculiarity, this membrane evidently follows Sir Isaac New-