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it seemed to have withdrawn.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--"

"Yes; what?" asked the doctor, leaning forward and peering into his
eyes.

"--I was overwhelmed with terror," said Pender, lowering his reedy
voice at the mere recollection of it.

He paused a moment and mopped his forehead. The scared, hunted look in
his eyes now dominated the whole face. Yet, all the time, the corners of
his mouth hinted of possible laughter as though the recollection of that
merriment still amused him. Th