“Evil,” he answered briefly, “appallingly evil, and yet mingled with the sheer wickedness of it was also a certain perverseness—the perversity of the unbalanced mind.”

He hesitated a moment and looked up sharply at his interlocutor. A shade of suspicion showed itself in his eyes.

“No,” laughed the doctor, “you need not fear that I’m merely humouring you, or think you mad. Far from it. Your story interests me exceedingly and you furnish me unconsciously with a number of clues as you tell it. You see, I possess some knowledge of my own as to these psychic byways.”

“I was shaking with such violent laughter,” continued the narrator, reassured in a moment, “though with no clear idea what was amusing me, that I had the greatest difficulty in getting up for the matches, and was afraid I should frighten the servants overhead with my explosions. When the gas was lit I found the room empty, of course, and the door locked as usual. Then I half dressed and went out on to the landing, my hilarity better under control, and proceeded to go downstairs. I wished to record my sensations. I stuffed a handkerchief into my mouth so as not to scream aloud and communicate my hysterics to the entire household.”

“And the presence of this—this——?”

“It was hanging about me all the time,” said Pender, “but for the moment it seemed to have withdrawn. Probably, too, my laughter killed all other emotions.”

“And how long did you take getting downstairs?”

“I was just coming to that I see you know all my ‘symptoms’ in advance, as it were; for, of course, I thought I should never get to the bottom. Each step seemed to take five minutes, and crossing the narrow hall at the foot of the stairs—well, I could have sworn it was half an hour’s journey had not my watch certified that it was a few seconds. Yet I walked fast and tried to push on. It was no good. I walked apparently without advancing, and at that rate it would have taken me a week to get down Putney Hill.”

“An experimental dose radically alters the scale of time and space sometimes——”

“But, when at last I got into my study and lit the gas, the change came horridly, and sudden as a flash of lightning. It was like a douche of icy water, and in the middle of this storm of laughter——”