along the corridor was another passage
leading to the yard above, and it was by this way that Hilda Glaum had
sped to the doctor's room.

Presently all were gone save one industrious worker, who sat peering
through the eye-piece of his microscope, immovable.

"That's our friend Bridgers," said Milsom, "he's all lit up with the
alkaloid of _Enythroxylon Coca_---- Well, Bridgers, nearly finished?"

"Huh!" grunted the man without turning.

Milsom shrugged his shoulders.

"We must let him finish what he's doing. He is quite oblivious to the
presence of anybody when he has these fits of industry. By the way, the
passing of our dear enemy"--he jerked his head to the passage
door--"will make no change in your plans?"

"How?"

"You have no great anxiety to marry the widow?"

"None," said the doctor.

"And she isn't a widow yet."

It was not Milsom who spoke, but the man at the bench, the industrious
worker whose eye was still at the microscope.

"Keep your comments to yourself," said van Heerden angrily, "finish your
work and get out."

"I've finished."

The worker rose slowly and loosening the tapes of his mask pulled it
off.

"My name is Beale," he said calmly, "I think we've met before. Don't
move, Milsom, unless you want to save living-expenses--I'm a fairly
quick shot when I'm annoyed."

Stanford Beale pushed back the microscope and seated himself on the edge
of the bench.

"You addressed me as Bridgers," he said, "you will find Mr. Bridgers in
a room behind that stack of boxes. The fact is he surprised me spying
and was all for shooting me up, but I induced him to come into my
private office, so to speak, and the rest was easy--he dopes, doesn't
he? He hadn't the strength of a rat. However, that is all beside the
point; Dr. van Heerden, what have you to say against my arresting you
out of hand on a conspiracy charge?"

Van Heerden smiled contemptuously.

"There are many things I can say," he said. "In the first place, you
have no authority to arrest anybody. You're not a police officer but
only an American amateur."

"American, yes; but amateur, no," said Beale gently. "As to the
authority, why I guess I can arrest you first and get the authority
after."

"On what charge?" demanded Milsom, "there is nothing secret about this
place, except Doctor van Heerden's association with it--a professional
man is debarred from mixing in commercial affairs. Is it a crime to run
a----"

He looked to van