"I can see two things, Dale," he said deliberately. "One of them is a dark, narrow room--a room piled with indistinct boxes and crates, and with an open door bearing the black number 4167. And in that open doorway, coming forward with slow steps--alive, with arms extended and a frightful face of passion--is a decayed human form. A corpse, Dale. A man who has been dead for many days, and is now--_alive_!" * * * * * M. S. turned slowly and pointed with upraised hand to the corpse on the grating. "That is why," he said simply, "this fellow died from horror." His words died into emptiness. For a moment I stared at him. Then, in spite of our surroundings, in spite of the late hour, the loneliness of the street, the awful thing beside us, I laughed. He turned upon me with a snarl. For the first time in my life I saw M. S. convulsed with rage. His old, lined face had suddenly become savage with intensity. "You laugh at me, Dale," he thundered. "By God, you make a mockery out of a science that I have spent more than my life in studying! You call yourself a medical man--and you are not fit to carry the name! I will wager you, man, that your laughter is not backed by courage!" I fell away from him. Had I stood within reach, I am sure he would have struck me. Struck me! And I have been nearer to M. S. for the past ten years than any man in London. And as I retreated from his temper, he reached forward to seize my arm. I could not help but feel impressed at his grim intentness. "Look here, Dale," he said bitterly, "I will wager you a hundred pounds that you will not spend the remainder of this night in the warehouse above you! I will wager a hundred pounds against your own courage that you will not back your laughter by going through what this fellow has gone through. That you will not prowl through the corridors of this great structure until you have found room 4167--_and remain in that room until dawn_!" * * * * * There was no choice. I glanced at the dead man, at the face of fear and the clutching, twisted hands, and a cold dread filled me. But to refuse my friend's wager would have been to brand myself an empty coward. I had mocked him. Now, whatever the cost, I must stand ready to pay for that mockery. "Room 4167?" I replied quietly, in a voice which I made every effort to control, lest he should discover the tremor in it. "Very well, I will do it!"