Half way through the second cigar Rupert shifted under his master's patent-leather boots and raised his huge head. His eyes blinked out of their sleep, then ceased to blink and became attentive. Then his ears, which had been lying down on each side of his head in the suavest attitude which such features of a dog can assume, lifted themselves up and pointed grimly forward as he listened to something. His flaccid legs contracted under him, and the muscles of his back quivered. Mab, less readily alert, quickly caught the infection of his attention, rolled over out of her sideways position and couched beside him. The movement of the dogs was not congenial to the doctor. Rupert's curious back, alert under his feet, communicated an immediate sense of disquiet to the very centre of his being. He said to Julian: "The acuteness of animal senses has its drawbacks. These dogs must have heard some sound in the street that is entirely inaudible to us. Well, Rupert, what is it? Lie down again and go to sleep." Stooping forward he put his hand on the dog's neck, and gave him a push, expecting him to yield readily, and tumble over onto the warm rug to sleep once more. But Rupert resisted his hand, and instead, got up, and stood at attention. Mab immediately followed his example. "What are they after, doctor?" said Julian. As he spoke a bell rang in the house. "Nemesis for prolonging the pleasure," Levillier said. "A summons to a patient, no doubt." As if in reply to the twitter of the bell, Rupert sprang forward and barked. He remained beside the door, waiting, while Mab barked too, nearer the fire. The bell sounded again, and the footstep of Lawler, who always sat up as late as his master, was heard on the stairs from the servants' part of the house. It passed them on its errand to the front door, but during its passage the excitement of the two dogs rapidly increased. They began to bark furiously and to bristle. "I never saw them like this before," the doctor said, not without anxiety. As he spoke Lawler opened the hall door. They heard the latch go and the faint voice of somebody in colloquy with him. For the dogs were now abruptly silent, but displayed the most curious savage intentness, showing their teeth, and standing each by the door as if sentinels on guard. The colloquy ceasing, steps again sounded in the hall, but more than Lawler's. Evidently the man was returning towards the room accompanied by somebody from the street. The doctor was keenly observing the mastiffs, and just as Lawler's hand struck upon the handle of the door to turn it, he suddenly called out sharply: "Lawler, you are not to open the door!" And as he called, the doctor ran forward between the two dogs and caught their collars in his two hands. They tugged and leaped to get away, but he held on. The surprised voice of the obedient Lawler was heard on the hither side of the door, saying: "I beg your pardon, sir." The doctor said hastily to Julian: