That is a rule of the apartment house. I chose the fortieth floor so that I would not be disturbed.
“I want no visitors tonight. Do you understand?”
“Yes, sir.”
The elevator door closed. Doctor Palermo, with a short laugh, twisted the push button beside the elevator door. The button screwed tight.
In so doing, it operated a secret mechanism which the physician had never before utilized. Until he should choose to release the button, it would be impossible for an elevator to come above the thirty-ninth floor.
Palermo rang the bell of his apartment. There was no response. The physician drew a peculiar key from his pocket and inserted it in a crevice between decorations of the door. The barrier opened.
Palermo stepped into the apartment. He stumbled over the bound form of Hassan. He evidenced no great surprise.
From the inside pocket of his full-dress coat, he drew a folding knife. He opened the instrument and cut the straps that bound the Arab. Hassan rose sheepishly.
“He came tonight?” questioned Palermo, in the language familiar to his servant.
The Arab nodded.