No one answered it, although there were three living beings within hearing distance.

One, Hassan, lay bound. Another, the man in black, was unconscious. The third had become a statue of bronze.

CHAPTER XIX. THE MASTER APPEARS

THE door of the elevator slid open at the fortieth floor. Doctor Palermo stepped out. He paused while he looked at the silent, calm-faced operator.

The man was apparently forty years of age. He wore an expression of indifference. His pale-gray eyes expressed no interest as they met the physician’s gaze.

“You are a new man here?” asked Doctor Palermo.

“On duty a few days, sir,” came the reply.

“What is your name?”

“Burbank, sir.”

“From now on, Burbank,” said Palermo, “do not bring the elevator to this floor, unless I summon you.