Woodhouse pocketed the military papers in the wallet and laid it down, the money untouched. The two white aids of Doctor Koch, who were standing by the folding doors, eyed the leather folder hungrily. Koch, meanwhile, had stripped off the jacket from the Englishman and was rolling up the right sleeve of his shirt. That done, he brought down from the top of the glass instrument case a wooden rack containing several test tubes, stoppled with cotton. One glass tube he lifted out of the rack and squinted at its clouded contents against the light. "A very handy little thing--very handy." Koch was talking to himself as much as to Woodhouse. "A sweet little product of the Niam Niam country down in Belgian Kongo. Natives think no more of it than they would of a water fly's bite; but the white man is----" "A virus of some kind?" the other guessed. "Of my own isolation," Doctor Koch answered proudly. He scraped the skin on the victim's arm until the blood came, then dipped an ivory spatula into the tube of murky gelatine and transferred what it brought up to the raw place in the flesh. "The action is very quick, and may be violent," he continued. "Our friend here won't recover consciousness for three days, and he will be unable to stand on his feet for two weeks, at least--dizziness, intermittent fever, clouded memory; he'll be pretty sick." "But not too sick to communicate with others," Woodhouse suggested. "Surely----" "Maybe not too sick, but unable to communicate with others," Doctor Koch interrupted, with a booming laugh. "This time to-morrow night our friend will be well out on the Libyan Desert, with some ungentle Bedouins for company. He's bound for Fezzan--and it will be a long way home without money. Who knows? Maybe three months." Very deftly Koch bound up the abrasion on the Englishman's arm with gauze, explaining as he worked that the man's desert guardians would have instructions to remove the bandages before he recovered his faculties. There would be nothing to tell the luckless prisoner more than that he had been kidnaped, robbed and carried away by tribesmen--a not uncommon occurrence in lower Egypt. Koch completed his work by directing his aids to strip off the rest of the unconscious man's uniform and clothe him in a nondescript civilian garb that Cæsar brought into the consultation room from the mysterious upper regions of the house. "Exit Captain Woodhouse of the signal service," the smiling doctor exclaimed when the last button of the misfit jacket had been flipped into its buttonhole, "and enter Captain Woodhouse of the Wilhelmstrasse." Turning, he bowed humorously to the lean-faced man beside him. He nodded his head at Cæsar; the latter dived into a cupboard at the far end of the room and brought out a squat flask and glasses, which he passed around. When the liquor had been poured, Doctor Koch lifted his glass and squinted through it with the air of a gentle satyr.