(See picture.) [Illustration: THE INSIDE OF THE EYE.] ~15.

The Nerves of Sight.~--But a person might have an eyeball with all the parts we have learned about and yet not be able to see.

Can you tell what more is needed?
There must be a nerve.

This nerve comes from some little nerve cells in the brain and enters the eyeball at the back of the eye; there it is spread out on the inside of the black lining of the white of the eye.
~16.

The Eyelids.~--Now we know all that it is necessary for us to learn about the eyeball, so let us notice some other parts about the eye.
First there are the eyelids.