[119] Again, the principal and dominant part in an animal is the head, and that has seven most necessary divisions: two eyes, an equal number of ears, two channels for the nostrils, and the mouth to make up seven, through which as Plato says, mortal things find their entrance, and immortal things their exit. For into the mouth do enter meat and drink, perishable food of a perishable body; but from out of it proceed words—the immortal laws of an immortal soul, by means of which rational life is regulated.