John turned away sharply, and began to pace the floor again with quickening steps. He knew as well as she what it must mean if he did not convince her then and there. In a few hours it would be too late. All sorts of mad and foolish ideas crossed his mind, but he rejected them one after the other. They were all ridiculous before the magnitude of her conviction. He had never seen her as she was now, not even when his father had died. He grew more and more desperate as the minutes passed. If his voice, his manner, his calm asseveration of the truth could not convince her, he asked himself if anything could. And if not, what could convince Katharine to-morrow? His recollections were all coming back vividly to him now. He remembered everything that had happened since the early morning. Strange to say,--and it is a well-known peculiarity of such cases,--he recalled distinctly the circumstances of his fall in the dark, and the absence of all knowledge of the direction he was taking afterwards. He knew, now, how he had wandered for hours in the great city, and he remembered many things he had seen, all of which were perfectly familiar, and each of which, at any other time, would have told him well enough whither he was going. He reconstructed every detail without effort. He even knew that when he had fallen over the heap of building material he had hurt one of his fingers, a fact which he had not noticed at the time. He looked at his hand now to convince himself. The finger was badly scratched, and the nail was torn to the quick. “Will nothing make you change your mind?” he asked, stopping in the middle of the room. “Will nothing I can do convince you?” “It would be hard,” answered Mrs. Ralston, shaking her head. “I’ve done all I can, then,” said John. “There’s nothing more to be said. You believe that I can lie to you and give you my word for a lie. Is that it?” “Don’t say it, please--it’s bad enough without any more words.” She rested her chin upon her hand once more and stared at the fire. “There is one thing more,” answered John, suddenly. “I think I can make you believe me still.” A bitter smile twisted Mrs. Ralston’s even lips, but she did not move nor speak. “Will you believe the statement of a good doctor on his oath?” asked John, quietly. Mrs. Ralston looked up at him suddenly. There was a strange expression in her eyes, something like hope, but with a little distrust. “Yes,” she said, after a moment’s thought. “I would believe that.” “Most people would,” answered John, with sudden coldness. “Will you send for a doctor? Or shall I go myself?” “Are you in earnest?” asked Mrs. Ralston, rising slowly from her seat and looking at him. “I’m in earnest--yes. You seem to be. It’s rather a serious matter to doubt my word of honour--even for my mother.”