Pender stared fixedly at his companion, plain horror showing in his eyes.  But he found nothing to say, and the doctor continued—­

“In your case, predisposed by the action of the drug, you have experienced the rush of these forces in undiluted strength.  They wholly obliterate in you the sense of humour, fancy, imagination,—­all that makes for cheerfulness and hope.  They seek, though perhaps automatically only, to oust your own thoughts and establish themselves in their place.  You are the victim of a psychical invasion.  At the same time, you have become clairvoyant in the true sense.  You are also a clairvoyant victim.”

Pender mopped his face and sighed.  He left his chair and went over to the fireplace to warm himself.

“You must think me a quack to talk like this, or a madman,” laughed Dr. Silence.  “But never mind that.  I have come to help you, and I can help you if you will do what I tell you.  It is very simple:  you must leave this house at once.  Oh, never mind the difficulties; we will deal with those together.  I can place another house at your disposal, or I would take the lease here off your hands, and later have it pulled down.  Your case interests me greatly, and I mean to see you through, so that you have no anxiety, and can drop back into your old groove of work tomorrow!  The drug has provided you, and therefore me, with a shortcut to a very interesting experience.  I am grateful to you.”

The author poked the fire vigorously, emotion rising in him like a tide.  He glanced towards the door nervously.

“There is no need to alarm your wife or to tell her the details of our conversation,” pursued the other quietly.  “Let her know that you will soon be in possession again of your sense of humour and your health, and explain that I am lending you another house for six months.  Meanwhile I may have the right to use this house for a night or two for my experiment.  Is that understood between us?”

“I can only thank you from the bottom of my heart,” stammered Pender, unable to find words to express his gratitude.

Then he hesitated for a moment, searching the doctor’s face anxiously.

“And your experiment with the house?” he said at length.

“Of the simplest character, my dear Mr. Pender.  Although I am myself an artificially trained psychic, and consequently aware of the presence of discarnate entities as a rule, I have so far felt nothing here at all.  This makes me sure that the forces acting here are of an unusual description.  What I propose to do is to make an experiment with a view of drawing out this evil, coaxing it from its lair, so to speak, in order that it may exhaust itself through me and become dissipated for ever.  I have already been inoculated,” he added; “I consider myself to be immune.”

“Heavens above!” gasped the author, collapsing on to a chair.

“Hell beneath! might be a more appropriate exclamation,” the doctor laughed.  “But, seriously, Mr. Pender, this is what I propose to do—­with your permission.”