The Parva Naturalia. On Sleep

On Sleep is a work of the Greek philosopher and scientist Aristotle, included in the collection Parva Naturalia.
The Parva Naturalia (a conventional Latin title first used by Giles of Rome: 'short treatises on nature') are a collection of seven works by Aristotle, which discuss natural phenomena involving the body and the soul. They form parts of Aristotle's biology.