2492. In the eye it is the brain itself, which expands, in order to turn unto or face the light.
2493. As the ear has its own brain, so also has the eye; the cerebrum is the optic brain. (Ed. 1st, 1811. §. 2317.) This is the rationale of our having two brains.
2494. Now the cortical or gray substance has been already diverted from the cerebrum to supply the olfactory sense. Its medullary or white substance remains for the eye. The medullary brain is the optic brain. The medullary is consequently the nobler part of the nervous system.
2495. The brain's medulla is homologous to the light; its exterior or cortical portion is related to the material light, the air.
2496. The eye is only a medullary brain, posited peripherically and in a nervous manner. The brain itself has elongated and become integument.
2497. The visual membrane (or retina) is the cerebral substance cystically expanded. It must be regarded as being originally a closed bladder or cyst. (Ed. 1st, 1811. §. 2321.)
2498. The optic nerve is itself hollow, and unites the cerebral with the orbitar cavity.
2499. The vitreous body, which fills out the cyst of the retina, is the cerebral medulla which has become transparent, or a semi-fluid albuminous mass.
2500. The sclerotic coat of the eye is the continuation of the brain's dura mater.
2501. The vascular or choroid coat of the eye is the continuation of the encephalic pia mater. All parts of the brain have been consequently continued into the eye.