One day Socrates succeeded in making her understand the manner in which images are formed in the brain, and how these images do not always correspond with external objects, or, at my rate, do not always correspond exactly.
"Hallucinations," he added, "are more often than not merely false perceptions.

One sees a thing, but one sees it badly, so that a feather-broom becomes a head of bristling locks, a red carnation is a beast's open mouth, and a chemise is a ghost in its winding-sheet.
Insignificant errors." From these arguments she derived sufficient strength to despise and dispel her visions of cats and dogs, or of persons who were living, and well known to her.

Yet she dreaded seeing the dead man again; and the mystic terrors nestling in the obscure crannies of her brain were more powerful than the demonstrations of science.

It was useless to tell her that the dead never returned; she knew very well that they did.
On this occasion Socrates once more advised her to find some distraction, to visit her friends, and by preference the more pleasant of her friends, and to avoid darkness and solitude, as her two most treacherous enemies.
And he added this prescription: "Especially must you avoid persons and things which may be connected with the object of your visions." He did not see that this was impossible.

Nor did Nanteuil.
"Then you will cure me, dear old Socrates," she said, turning upon him her pretty grey eyes, full of entreaty.
"You will cure yourself my child.