421. (xvii) Love or the will is defiled in and by the understanding, if they are not elevated together; since, if love is not elevated, it remains impure (as stated above, n. 419-420); and as long as that is so, it loves what is impure, such as revenge, hatred, deceit, blasphemy, adultery; for these are then its affections and are called lusts; while it rejects everything that has to do with charity, justice, sincerity, truth, and chastity. Love is said to be defiled in and by the understanding: in the understanding, when love is affected by those impure things; by the understanding, when love causes the things of wisdom to become its servants, and still more when it perverts, falsifies, and adulterates them. There is no need to say more of the state of the heart or its blood in the lungs corresponding to these things, than was said above (n. 420), except that instead of purification of the blood its defilement takes place, and instead of nutrition of the blood by fragrant things as it is in heaven, nutrition is effected by stinking things, exactly as in hell.