Timaeus: is called “sap”; but inasmuch as the several sorts have become dissimilar owing to intermixture, most of the kinds thus produced are unnamed. Four of these kinds, however, being fiery and specially conspicuous, have received names. Of these, that which is heating to the soul as well as the body is called “wine”; that which is smooth and divisive of the vision, and therefore bright to look upon and gleaming and glistening in appearance, is the species “oil,” including pitch and castor oil and olive oil itself and all the others that are of the same character;

We however perceive that some things become immediately the cause of a great change in quality, as is evident in wine. For when it is drank...