3. If the eyes ache, the light should be softened or the position of the book or work changed, or else the eyes should be rested.
4. Sound in the air goes into the ear and strikes against a drum. Bones then carry the sound to the ear nerves.
5. Air snuffed up the nose gives the sense of smell. Smell tells us if the air or food is fit for use.
6. Taste tells us whether food is fit for use. Men can learn to like the taste of wrong things like tobacco or alcohol.
The Human Skeleton, showing position of bones.