The Confidence-Man - pg. 88

"From evil comes good. Distrust is a stage to confidence. How has it proved in our interview? But your voice is husky; I have let you talk too much. You hold your cure; I leave you. But stay -- when I hear that is yours, I will not, like some I know, vainly make boasts; but, giving glory where all glory is due, say, with devout herb-doctor, Iapis in Virgil, when, in the unseen but efficacious presence of Venus, he with simples healed the wound of Aeneas: --

'This is no mortal work, no cure of mine,
Nor art's effect, but done by power divine.'"