Defects of sight : their nature, causes, prevention, and general management / by T. Wharton Jones.

  • Jones, Thomas Wharton, 1808-1891.
Date:
1856
Catalogue details

Licence: Public Domain Mark

Credit: Defects of sight : their nature, causes, prevention, and general management / by T. Wharton Jones. Source: Wellcome Collection.

Provider: This material has been provided by the Francis A. Countway Library of Medicine, through the Medical Heritage Library. The original may be consulted at the Francis A. Countway Library of Medicine, Harvard Medical School.

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    DEFECTS OF SIGHT: THEIR NATURE, CAUSES, PREVENTION, AND GENERAL MANAGEMENT, PART T. CHAPTEB I. STRUCTURE OF THE EYES AND NATURE OP THE SENSE OE SIGHT. The optic nerves or special nerves of sight-—two in number—are each at one end connected with the brain and at the other expanded into a nervous mem- brane, named retina, which lines the interior of the back part of the eyeball. Like telegraphic wires, the optic nerves constitute the media of transmission between the retina, on which the impressions of sight are made, and the brain, where the sensations of sight are perceived. The segment of the eyeball in front of the retina is a dioptric apparatus or system of lenses, by which the rays of light entering the eye from external objects are so refracted or bent that they are made to