I know nothing about your Wilhelmstrasse or your number. If I did not think you were drunk I'd have you held here, to be turned over to the military as a spy. Now, go before I change my mind."

Again the querulous protestation of Capper, met by the doctor's peremptory order. The captain heard the front door close. A long wait, and Doctor Koch's black beard, with the surmounting eyes of thick glass, appeared at a parting of the folding doors. Woodhouse, the tiny thermometer still sticking absurdly from his mouth, met the basilisk stare of those two ovals of glass with a coldly casual glance. He removed the thermometer from between his lips and read it, with a smile, as if that were part of playing a game. Still the ghastly stare from the glass eyes over the bristling beard, searching--searching.

"Well," Woodhouse said lightly, "no need of an alibi evidently."

Doctor Koch stepped into the room with the lightness of a cat, walked to a desk drawer at one side, and fumbled there a second, his back to his guest. When he turned he held a short-barreled automatic at his hip; the muzzle covered the shirt-sleeved man in the chair.

"Much need--for an alibi--from you!" Doctor Koch croaked, his voice dry and flat with rage. "Much need. Mister Nineteen Thirty-two. Commence your explanation immediately, for this minute my temptation is strong--very strong--to shoot you for the dog you are."

"Is this--ah, customary?" Woodhouse twiddled the tiny mercury tube between his fingers and looked unflinchingly at the small round mouth of the automatic. "Do you make a practise of consulting a--friend with a revolver at your hip?"

"You heard--what was said in there!" Koch's forehead was curiously ridged and flushed with much blood.

"Did you ask me to listen? Surely, my dear Doctor, you have provided doors that are soundproof. If I may suggest, isn't it about time that you explain this--this melodrama?" The captain's voice was cold; his lips were drawn to a thin line. Koch's big head moved from side to side with a gesture curiously like that of a bull about to charge, but knowing not where his enemy stands. He blurted out:

"For your information, if you did not overhear: An Englishman comes just now to address me familiarly as of the Wilhelmstrasse. He comes to say he was sent to report to me; that his number in the Wilhelmstrasse is nineteen thirty-two--nineteen thirty-two, remember; and I am to give him orders. Please explain that before I pull this trigger."

"He showed you his number--his ticket, then?" Woodhouse added this parenthetically.

"The man said his ticket had been stolen from him some time after he left Paris--stolen from the head of his cane, where he had it concealed. But the number was nineteen thirty-two." The doctor voiced this last doggedly.

"You have, of course, had this man followed," the other put in. "You have not let him leave this house alone."

"Caesar was after him before he left the garden gate--naturally. But--"

Woodhouse held up an interrupting hand.

"Pardon me. Doctor Koch; did you get this fellow's name?"

"He refused to give it--said I wouldn't know him, anyway."

"Was he an undersized man, very thin, sparse hair, and a face showing dissipation?" Woodhouse went on. "Nervous, jerky way of talking--fingers to his mouth, as if to feel his words as they come out--brandy or wine breath? Can't you guess who he was?"

"I guess nothing."

"The target!"

At the word Louisa had used in describing Capper to Woodhouse, Koch's face underwent a change. He lowered his pistol.