A view of the under surface of the brain, which rests on the floor of the skull, shows the origin of important nerves, called the cranial nerves, the cerebellum, the structure connecting the optic nerves (optic commissure), the bridge of nervous matter (pons Varolii) connecting the two hemispheres of the cerebellum, and lastly numerous and well-marked convolutions. 268.

A view of the under surface of the brain, which rests on the floor of the skull, shows the origin of important nerves, called the cranial nerves, the cerebellum, the structure connecting the optic nerves (optic commissure), the bridge of nervous matter (pons Varolii) connecting the two hemispheres of the cerebellum, and lastly numerous and well-marked convolutions. 268.

The second pair are the optic nerves, which, under the name of the optic tracts, run down to the base of the brain, from which an optic nerve passes to each eyeball.

The second pair are the optic nerves, which, under the name of the optic tracts, run down to the base of the brain, from which an optic nerve passes to each eyeball.

The second pair are the optic nerves, which, under the name of the optic tracts, run down to the base of the brain, from which an optic nerve passes to each eyeball.

A, chiasm of the optic nerves; B, optic tracts; C, motor oculi communis; D, fifth nerve; E, motor oculi externus; F, facial nerve; H, auditory nerve; I, glosso-pharyngeal nerve; K, pneumogastric; L, spinal accessory; M, cervical nerves; N, upper extremity of spinal cord; O, decussation of the anterior pyramids; R, anterior pyramids of the medulla oblongata; S, pons Varolii.

A, chiasm of the optic nerves; B, optic tracts; C, motor oculi communis; D, fifth nerve; E, motor oculi externus; F, facial nerve; H, auditory nerve; I, glosso-pharyngeal nerve; K, pneumogastric; L, spinal accessory; M, cervical nerves; N, upper extremity of spinal cord; O, decussation of the anterior pyramids; R, anterior pyramids of the medulla oblongata; S, pons Varolii.

The optic nerves serve as the sensory, and the facial nerves as the motor, conductors.

Impressions have reached the seeing-center in the brain from irritation of the optic nerve, producing the same effect as real lights would cause.

The orbit is pierced through its posterior surface by an opening through which the nerve of sight, the optic, passes to the eyeball.

We may think of the optic nerve holding the eyeball much as the stem holds the apple.

It is really an expansion of the ultimate fibers of the optic nerve, by means of which impressions are sent to the brain.

The retina is not sensitive where the optic nerve enters the eyeball.

A, attachment of tendon connected with the three recti muscles; B, external rectus, divided and turned downward, to expose the internus rectus; C, inferior rectus; D, internal rectus; E, superior rectus; F, superior oblique; H, pulley and reflected portion of the superior oblique; K, inferior oblique; L, levator palpebri superioris; M, middle portion of the same muscle (L); N, optic nerve.

In other instances, the congestion of the optic nerve is so serious as to involve a progressive wasting of that organ, producing at first a hazy dimness of vision which gradually becomes worse and worse, till total blindness may ensue.

Take a freshly removed ox-eye; dissect the sclerotic from that part of its posterior segment near the optic nerve.

At a certain distance the circle will disappear, i.e., when its image falls on the entrance of the optic nerve.

In these cases one loses the impressions produced by the convergence of the optic axes, which are important factors in judging of distance.

Optic (Gr. o#1F40;pteyo, to see).

The innermost of the three tunics, or coats, of the eyeball, being an expansion of the optic nerve.

This optic glass of intuition Here, take it, view his true condition.'

At such times it is as if the optic nerve of the mind throughout whole communities became distorted, till in the noseless and black-robed Reaper it discerned an angel of very loveliness.

By Oliver Optic.

He could not, owing to his short sight, read men's faces across the floor of the House, but he did not require the aid of any optic nerve to see the petty secrets of their souls.

I do not believe that any human being ever lived whose eyes habitually wore that expression: only by a violent effort could the expression be produced, and then for a very short time, without serious injury to the optic nerves.