This is what Tertullian asserts: “They inflict grievous afflictions on bodies and sudden assaults on the soul; they twist the limbs, creeping in unseen,” and so on. It is also what Lemnius undertakes to prove: “Evil spirits mingle with corrupted humours and black bile,” and so forth.

And Jason Pratensis says that the Devil, being a subtle spirit that cannot be grasped, can easily slip and wind his way into human bodies and, cunningly lodged in our internal organs, damage our health, terrify our souls with frightening dreams and shake our minds with fits of frenzy. Elsewhere he says: “These unclean spirits, settled in our bodies and now mixed with our melancholy humours, seem to triumph and play as though in another heaven.”

So he argues, adding that they enter and leave our bodies as bees do a hive, provoking and tempting us according to the natural inclinations of our bodily constitution, wherever it is most susceptible to deception. Agrippa and Lavater are convinced that this humour invites the Devil wherever it exists in excess; that melancholy people are more exposed than anyone else to diabolical temptations and illusions, more ready to receive them, and most easily acted upon by the Devil.

But whether this happens through external demonic assault, possession or some other means, I will not decide: it is a difficult question. Delrio the Jesuit, volume 3, book 6; Sprenger and his colleague in The Hammer of Witches; Peter Thyraeus the Jesuit, in his books On the Possessed, On Haunted Places and On Night Terrors; Girolamo Menghi in The Scourge of Demons; and other papal writers of that sort appear to confirm it by their exorcisms and conjurations, having fabricated many stories for the purpose.

A nun ate a lettuce without saying grace or making the sign of the cross over it, and was instantly possessed. Durandus, Rationale, book 6, chapter 86, section 8, relates that at Bologna he saw a young woman possessed by two devils after eating an unblessed pomegranate, as she afterwards confessed when cured by exorcism.

For this reason our papists so often cross themselves, “lest a demon dare to enter,” and exorcise every kind of food as otherwise unclean or accursed—a practice Bellarmine defends. I find many such stories among papal writers to prove their assertions; let them vindicate their own credibility. I will cite a few of this kind from physicians of the highest reputation.

Cornelius Gemma, On the Divine Signs of Nature, book 2, chapter 4, relates that in 1571 a young woman called Katherine Gualter, a cooper’s daughter, suffered such strange attacks and convulsions that sometimes three men could not hold her. She passed a live eel, a foot and a half long, which he saw and touched himself; but afterwards the eel vanished.

She vomited some twenty-four pounds of foul matter of every colour twice a day for fourteen days. Afterwards she expelled great balls of hair, pieces of wood, pigeon droppings, parchment, goose droppings and coals; then two pounds of pure blood; then coals and stones again, some bearing inscriptions and larger than a walnut, and some pieces of glass, brass, and so on. Besides this she had fits of laughter, weeping and trance. “And this,” he says, “I saw with horror”—I saw it with horror.

They could do nothing for her with medicine and left her to the clergy. Marcellus Donatus, Medical Wonders, book 2, chapter 1, has a similar story of a countryman who had four knives in his belly, “toothed like a saw”—serrated like a saw—each a span long, and a coil of hair in the shape of a ball, with much similar rubbish, astonishing to see. As for how it entered his guts, he concludes: “Certainly by nothing other than a demon’s cunning and deceit.”

Lange, Medical Letters, book 1, letter 38, has many accounts of this kind, as does Cristóbal de Vega. Weyer, Schenck and Scribonius all agree that these things are done through the Devil’s cunning and illusion. If you ask why, it is to exercise our patience. For, as Tertullian maintains, “Virtue is not virtue unless it has an opponent to overcome and thereby display its strength.”

It is to test us and our faith, because of our offences and as punishment for our sins. They do it with God’s permission: “executioners of God’s just vengeance,” as Tolosanus calls them—executioners of his will. Or rather, as David says in Psalm 78, verse 49: “He unleashed upon them his fierce anger, indignation, wrath and distress, by sending out evil angels.”

So he afflicted Job, Saul, the lunatics and possessed people whom Christ cured: Matthew 4 and 8; Luke 4 and 11; Luke 13; Mark 9; Tobit 8:3; and so forth. This, I say, happens as punishment for sin, for their lack of faith, unbelief, weakness, distrust, and the like.