Note 1 — CANTO XVIII.

In his discourse in the preceding canto, Virgil has declared that neither the Creator nor his creatures are ever without love, either native in the soul, or proceeding from the mind. Here he explains how the mind is disposed to love by inclination to an image within itself of some object which gives it pleasure. This inclination is natural to it; or in his phrase, nature is bound anew in man by the pleasure which arouses the love. All this is a doctrine derived directly from St. Thomas Aquinas. “It is the property of every nature to have some inclination, which is a natural appetite, or love.”—Summa Theol., 1, lxxvi. i.