ddenly come over Laverick. He
felt himself in danger--he had no idea how, or in what way--but
the conviction was there. He took every step fully alert,
absolutely on his guard.

They were almost within sight of Holborn when a cry from the
bystanders caused them to look away into the middle of the road.
Laverick only cast one glance there and abandoned every instinct
of curiosity, thinking once more only of himself and his own
position. With the constable, however, it was naturally different.
He saw something which called at once for his intervention, and
he immediately forgot the somewhat singular task upon which he
was engaged. A man had fallen in the middle of the street, either
knocked down by the shaft of a passing vehicle or in some sort of
fit. There was a tangle of rearing horses, an omnibus was making
desperate efforts to avoid the prostrate body. The constable
sprang to the rescue. Laverick, instantly suspicious and realizing
that there was no one in front of him, turned swiftly around. He
was just in time to receive upon his left arm the blow which had
been meant for the back of his head. He was confronted by a man
dressed exactly as he himself was, in morning coat and silk hat,
a man with long, lean face and legal appearance, such a person as
would have passed anywhere without attracting a moment's suspicion.
Yet, in the space of a few seconds he had whipped out from one
pocket, with the skill almost of a juggler, a vicious-looking
life-preserver, and from the other a pocket-handkerchief soaked
with chloroform. Laverick, quick and resourceful, feeling his
left arm sink helpless, struck at the man with his right and sent
him staggering against the wall. The handkerchief, with its load
of sickening odor, fell to the pavement. The man was obviously
worsted. Laverick sprang at him. They were almost unobserved,
for the crowd was all intent upon the accident in the roadway.
With wonderful skill, his assailant eluded his attempt to close,
and tore at his coat. Laverick struck at him again but met only
the air. The man's fingers now were upon his pocket, but this
time Laverick made no mistake. He struck downward so hard that
with a fierce cry of pain the man relaxed his hold. Before he
could recover, Laverick had struck him again. He reeled into the
crowd that was fast gathering around them, attracted by what
seemed to be a fight between two men of unexceptionable appearance.
But there was to be