"Very well, then, let us put the old man's joy down as one of the mysteries to be explained later. Have you thought of him as a possible accomplice?" "Certainly; but this supposition is open to the same objection as that which made him the motive power in this murder. One is not driven insane by an expected horror. It takes shock to unsettle the brain. He was not looking for the death of his master." "True. We may consider that matter as settled. Bartow was an innocent witness of this crime, and, having nothing to fear, may be trusted to reproduce in his pantomimic action its exact features." "Very good. Continue, madam. Nothing but profit is likely to follow an argument presented by Miss Butterworth." The old detective's tone was serious, his manner perfect; but Miss Butterworth, ever on the look-out for sarcasm from his lips, bridled a little, though in no other way did she show her displeasure. "Let us, then, recall his precise gestures, remembering that he must have surprised the assailant from the study doorway, and so have seen the assault from over his master's shoulder." "In other words, directly in front of him. Now what was his first move?" "His first move, as now seen, is to raise his right arm and stretch it behind him, while he leans forward for the imaginary dagger. What does that mean?" "I should find it hard to say. But I did not see him do that. When I came upon him, he was thrusting with his left hand across his own body--a vicious thrust and with his left hand. That is a point, Mr. Gryce." "Yes, especially as the doctors agree that Mr. Adams was killed by a left-handed blow." "You don't say! Don't you see the difficulty, then?" "The difficulty, madam?" "Bartow was standing face to face with the assailant. In imitating him, especially in his unreasoning state of mind, he would lift the arm opposite to the one whose action he mimics, which, in this case, would be the assailant's right. Try, for the moment, to mimic my actions. See! I lift this hand, and instinctively (nay, I detected the movement, sir, quickly as you remembered yourself), you raise the one directly opposite to it. It is like seeing yourself in a mirror. You turn your head to the right, but your image turns to the left." Mr. Gryce's laugh rang out in spite of himself. He was not often caught napping, but this woman exercised a species of fascination upon him at times, and it rather amused than offended him, when he was obliged to acknowledge himself defeated. "Very good! You have proved your point quite satisfactorily; but what conclusions are to be drawn from it? That the man was not left-handed, or that he was not standing in the place you have assigned to him?"