When we look at an object the lens of the eye makes a picture on the nerve of sight, at the back part of the eyeball.
11.

To keep the eyes healthy we should be careful not to tax them long at a time with fine work, or to use them in a poor light.
12.

The nerves of smell are placed in the upper part of the inside of the nose.
13.

"Colds" often destroy the sense of smell.
14.

The nerves of taste are placed in the tongue and palate.
15.