Tradux is a layer used for propagating vines; and hence the stock by which anything is produced directly from, and in connexion with, the original source. Swift's strangely varied reading is again illustrated by this. He must almost certainly have had in his mind the words in which Prudentius (Apotheosis, v. 915) describes a heresy which attributes a material origin to the soul by tracing it as coming 'traduce carnis . . . sanguinis exemplo. ' The discussion as to the 'traduction' of the soul enters into Brown's Religio Medici; and Sir Kenelm Digby, in his Observations thereon, uses this phrase ex traduce. ' The soul,' he says, 'is not ex traduce, and yet hath a strange kind of near dependence on the body, which is, as it were, God's instrument to create it by.'