Letters on natural magic, addressed to Sir W. Scott / [Sir David Brewster].
- David Brewster
- Date:
- 1833
Licence: Public Domain Mark
Credit: Letters on natural magic, addressed to Sir W. Scott / [Sir David Brewster]. Source: Wellcome Collection.
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![an egg, and fills up the rest of the eye. Behind the vitreous humour, there is spread out on the inside of the eye-bail a fine delicate membrane, called the retina, which is an expansion of the opiic nerve, entering the back of the eye, and commu- nicating with the brain. A perspective view and horizontal section of the left eye, shown in tlie annexed figure, will convey a popular idea of its structure. It is, as it were, a small camera obscura, by means of which the pic- tures of external objects are painted on the retina,, and in a way of which we are ignorant, it conveys tlie impression of them to the brain. Fiff. ]. This wonderful organ may be considered as the sentinel which guards the pass between the worlds of matter and of spirit, and through which all their communications are interchanged. The optic nerve is the channel by which the mind peruses the hand-writing of Nature on the retina, and tlirough which it transfers to that material tablet its deci-](https://iiif.wellcomecollection.org/image/b22030050_0024.jp2/full/800%2C/0/default.jpg)
