"On me?" gasped Pender, catching his breath.
"Not exactly," the doctor said, with a grave smile, "but with your assistance, perhaps. I shall want to test the conditions of the house—to ascertain, impossible, the character of the forces, of this strange personality that has been haunting you—"
"At present you have no idea exactly who—what—why—" asked the other in a wild flurry of interest, dread and amazement.
"I have a very good idea, but no proof rather," returned the doctor. "The effects of the drug in altering the scale of time and space, and merging the senses have nothing primarily to do with the invasion. They come to any one who is fool enough to take an experimental dose. It is the other features of your case that are unusual. You see, you are now in touch with certain violent emotions, desires, purposes, still active in this house, that were produced in the past by some powerful and evil personality that lived here. How long ago, or why they still persist so forcibly, I cannot positively say. But I should judge that they are merely forces acting automatically with the momentum of their terrific original impetus."
"Not directed by a living being, a conscious will, you mean?"
"Possibly not—but none the less dangerous on that account, and more difficult to deal with. I cannot explain to you in a few minutes the nature of such things, for you have not made the studies that would enable you to follow me; but I have reason to believe that on the dissolution at death of a human being, its forces may still persist and continue to act in a blind, unconscious fashion. As a rule they speedily dissipate themselves, but in the case of a very powerful personality they may last a long time. And, in some cases—of which I incline to think this is one—these forces may coalesce with certain non-human entities who thus continue their life indefinitely and increase their strength to an unbelievable degree. If the original personality was evil, the beings attracted to the left-over forces will also be evil. In this case, I think there has been an unusual and dreadful aggrandisement of the thoughts and purposes left behind long ago by a woman of consummate wickedness and great personal power of character and intellect. Now, do you begin to see what I am driving at a little?"
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."
"Of course, of course," cried the other, "you have my permission and my best wishes for success. I can see no possible objection, but—"
"But what?"
"I pray to Heaven you will not undertake this experiment alone, will you?"
"Oh, dear, no; not alone."
"You will take a companion with good nerves, and reliable in case of disaster, won't you?"
"I shall bring two companions," the doctor said.
"Ah, that's better. I feel easier. I am sure you must have among your acquaintances men who—"
"I shall not think of bringing men, Mr. Pender."
The other looked up sharply.
"No, or women either; or children."
"I don't understand. Who will you bring, then?"
"Animals," explained the doctor, unable to prevent a smile at his companion's expression of surprise—"two animals, a cat and a dog."
Pender stared as if his eyes would drop out upon the floor, and then led the way without another word into the adjoining room where his wife was awaiting them for tea.
II
A few days later the humorist and his wife, with minds greatly relieved, moved into a small furnished house placed at their free disposal in another part of London; and John Silence, intent upon his approaching experiment, made ready to spend a night in the empty house on the top of Putney Hill. Only two rooms were prepared for occupation: the study on the ground floor and the bedroom immediately above it; all other doors were to be locked, and no servant was to be left in the house. The motor had orders to call for him at nine o'clock the following morning.
And, meanwhile, his secretary had instructions to look up the past history and associations of the place, and learn everything he could concerning the character of former occupants, recent or remote.
The animals, by whose sensitiveness he intended to test any unusual conditions in the atmosphere of the building, Dr. Silence selected with care and judgment. He believed (and had already made curious experiments to prove it) that animals were more often, and more truly, clairvoyant than human beings. Many of them, he felt convinced, possessed powers of perception far superior to that mere keenness of the senses common to all dwellers in the wilds where the senses grow specially alert; they had what he termed "animal clairvoyance," and from his experiments with horses, dogs, cats, and even birds, he had drawn certain deductions, which, however, need not be referred to in detail here.
Cats, in particular, he believed, were almost continuously conscious of a larger field of vision, too detailed even for a photographic camera, and quite beyond the reach of normal human organs. He had, further, observed that while dogs were usually terrified in the presence of such phenomena,