"Poor wretch!" he thought. "But what is the physical agony of a night to the mental anguish of a lifetime?" "Once! once!" she gasped; "or kill me." Then, as he stood implacable, "Kill me! Kill me!" He picked her up, put a fresh night-gown on her, and laid her on the bed. She remained as he placed her, too weak to move, her eyes staring at the ceiling above the big four-posted bed. He returned to his chair and looked at his watch. "She may live two hours," he thought. "Possibly three. It is only twelve. There is plenty of time." The room grew as still as the mountain-top whence he had that day returned. He attempted to read, but could not. The sense of supreme power filled his brain. He was the gigantic factor in the fates of four. Then Circumstance, the outwardly wayward, the ruthlessly sequential, played him an ugly trick. His eyes, glancing idly about the room, were arrested by a big old-fashioned rocking-chair. There was something familiar about it. Soon he remembered that it resembled one in which his mother used to sit. She had been an invalid, and the most sinless and unworldly woman he had ever known. He recalled, with a touch of the old impatience, how she had irritated his active, aspiring, essentially modern mind with her cast-iron precepts of right and wrong. Her conscience flagellated her, and she had striven to develop her son's to the goodly proportion of her own. As he was naturally a truthful and upright boy, he resented her homilies mightily. "Conscience," he once broke out impatiently, "has made more women bores, more men failures, than any ten vices in the rogues' calendar." She had looked in pale horror, and taken refuge in an axiom: "Conscience makes cowards of us all." He moved his head with involuntary pride. The greatest achievement of civilization was the triumph of the intellect over inherited impressions. Every normal man was conscientious by instinct, however he might outrage the sturdy little judge clinging tenaciously to his bench in the victim's brain. It was only when the brain grew big with knowledge and the will clasped it with fingers of steel that the little judge was throttled, then cast out. Conscience. What was it like? The doctor had forgotten. He had never committed a murder nor a dishonorable act. Had the impulse of either been in him, his cleverness would have put it aside with a smile of scorn. He had never scrupled to thrust from his path whoever or whatever stood in his way, and had stridden on without a backward glance. His profession had involved many experiments that would have made quick havoc of even the ordinary man's conscience. Conscience. An awkward guest for an unsuspected murderer; for the groundling whose heredity had not been conquered by brain. Fancy being pursued by the spectre of the victim!