muscle shows
signs of fatigue and is scarcely able to lift a weight easily lifted in
normal conditions. Other fatigue products may be discovered; but, if
present in large quantity or in small quantity for a long time, each of
the substances I have named will cause depression or fatigue of muscles.

"Further than that," continued Kennedy, "the depressing influence of
these substances on what is known as striated muscle--heart muscle--is
well known. The physician at the Idlewild might very well have mistaken
the cause of the relaxation of Murchie's heart. For German investigators
have also found that the toxin of fatigue, when injected into the
circulation of a fresh animal, may not only bring on fatigue but may
even cause death--as it did finally here." Kennedy paused. "Lady Lee,"
he said, looking from one to the other of his audience keenly, "Lady
Lee was the first victim of the fiendish cunning of this--"

A shrill voice interrupted.

"But Lady Lee won the race!"

It was McGee, the jockey. Kennedy looked at him a moment, then tapped
another beaker on the table before him.

"Weichardt has also obtained, by the usual methods," he replied, "an
antitoxin with the power of neutralizing the fatigue properties of the
toxin. You thought Lady Lee was not friendly with strangers that morning
at the track. She was not, when the stranger jabbed a needle into her
neck and pumped an extra large dose of the antitoxin of fatigue into her
just in time to neutralize, before the race, the long series of
injections of fatigue toxin."

Kennedy was now traveling rapidly toward the point which he had in view.
He drew from his pocket the little bottle which he had picked up that
night in the cabaret saloon.

"One word more," he said, as he held up the bottle and faced Cecilie
Safford, who was now trembling like a leaf ready to fall: "If one with
shattered nerves were unable to sleep, can you imagine what would be a
most ideal sedative--especially if to take almost any other drug would
be merely to substitute that habit for another?"

He waited a moment, then answered his own question.

"Naturally," he proceeded, "it might be, theoretically at least, a small
dose of those products of fatigue by which nature herself brings on
sleep. I am not going into the theory of the thing. The fact that you
had such a thing is all that interests me."

I watched the girl's eyes as they were riveted on Kennedy. She seemed to
be fascinated, horrif