Then, what can be believed and what can be proved?
The materialists have taken the trouble to revise the accounts of the sorcery trials of old.

They have found in the possession-cases of the Ursulines of Loudun and the nuns of Poitiers, in the history, even, of the convulsionists of Saint Medard, the symptoms of major hysteria, the same contractions of the whole system, the same muscular dissolutions, the same lethargies, even, finally, the famous arc of the circle.

And what does this demonstrate, that these demonomaniacs were hystero-epileptics?
Certainly.

The observations of Dr.Richet, expert in such matters, are conclusive, but wherein do they invalidate possession?
From the fact that the patients of La Salpetriere are not possessed, though they are hysterical, does it follow that others, smitten with the same malady as they, are not possessed?
It would have to be demonstrated also that all demonopathics are hysterical, and that is false, for there are women of sound mind and perfectly good sense who are demonopathic without knowing it.

And admitting that the last point is controvertible, there remains this unanswerable question: is a woman possessed because she is hysterical, or is she hysterical because she is possessed?
Only the Church can answer.