"Fool!" I interrupted hoarsely--for my suspense was painfully intense. "What object could I serve? Do as I bid you! Do as I bid you!" I pressed his hands more tightly, and with all my strength I strove to subordinate his will to mine. I succeeded. "I'll trust you!" he muttered in a tense trembling whisper. "I'll trust you, Dagmar. God forgive you if you play me false!" There was something so infectious in his emotion that I felt myself tremble too, and involuntarily I followed the terrified suspicious glances that he darted about the room. "Amen!" I cried. "Now Cavanagh--" But he uttered an exclamation. "Oh! You are hurting me!" he cried. In my excitement I had forgotten the man's womanish physique, and I had cruelly crushed his hands. Upon such trifling incidents does an ironical malicious fate love to hang tremendous issues! I do not remember if I have previously mentioned the fact that the thumb of Sir William Dagmar's right hand lacks a joint. But such is the case. He had lost it through a gunshot when a lad. Now this circumstance constituted the one flaw in my disguise, for my hands are perfect. In the earlier part of the interview I had been careful to conceal them from view, but startled by Cavanagh's cry of pain and words of reproach I did an unpardonably foolish thing. I permitted myself, for one second, to be victimized by a human impulse. Forgetting everything except that I had hurt him and was sorry, I opened my hands--and looked down at his delicate crumpled fingers from which my brutal grasp had driven all the blood. On the instant I realized my own fatuity and attempted to repair my error. It was, however, too late. Mr. Cavanagh staggered back a pace. At first he looked dazed, almost stunned, but his face turned livid as I watched it and his eyes filled with flame. They swept over me with glances that scorched, that wished intemperately to harm, to avenge--to kill! Finally they met my eyes, and for a long moment we gazed into each other's souls. His was full of rage, despair and terror--mine of savage self-contempt and baffled hope, and fiery but impotent regret. "Who are you?" he hissed. "Curse you--who are you?" Desperate diseases require desperate remedies. Already there floated before my eyes visions of police, of handcuffs, courthouses and gaols. I saw myself a prisoner serving sentence for criminal impersonation. A shudder of horror shot through my frame. Then came a blessed inspiration. "Mr. Cavanagh belongs to a society--" cried my thoughts--"which must have a criminal foundation, since its laws dare impose such a penalty as suicide for their infraction." I set my teeth together with a grim snap and hoarsely retorted to his question. "You wish to know who I am, sir. Well, I shall answer you in part. I am a detective from Scotland Yard!" The effect of my announcement was completely terrible.