The young man's voice trembled, but it was with anger and impatience, not with fear. The astrologer recognised the change in him, and fell into his place. He went, without further demur, to a little shelf in the darkest corner of the laboratory, whence he reached down a crucible. He was in the act of peering into this, with his back to his visitor, when M. de Vidoche uttered a startled cry, and, springing towards him, seized his arm. "You fiend!" the young man hissed--he was pale to the lips, and shook as with an ague--"there is someone there! There is someone listening!" [Illustration: "FOR A SECOND THE MAN IN BLACK STOOD BREATHLESS" (_p_. 92).] For a second the man in black stood breathless, his hand arrested, the shadow of his companion's terror darkening his face. M. de Vidoche pointed with a trembling finger to the staircase which led to the farther part of the house, and on this the two bent their sombre, guilty eyes. The lamp burned unsteadily, giving out an odour of smoke. The room was full of shadows, uncouth distorted shapes, that rose and fell with the light, and had something terrifying in their sudden appearances and vanishings. But in all the place there was nothing so appalling or so ugly as the two vicious, panic-stricken faces that glared into the darkness. The man in black was the first to break the silence. "What did you hear?" he muttered at length, after a long, long period of waiting and watching. "Someone moved there," Vidoche answered, under his breath. His voice still trembled; his face was livid with terror. "Nonsense!" the other answered. He knew the place, and was fast recovering his courage. "What was the sound like, man?" "A dull, heavy sound. Someone moved." M. Nôtredame laughed, but not pleasantly. "It was the toad," he said. "There is no other living thing here. The door on the staircase is locked. It is thick, too. A dozen men might be behind it, yet they would not hear a word that passed in this room. But come; you shall see." He led the way to the farther end of the room, and, moving some of the larger things, showed M. de Vidoche that there was no one there. Still, the young man was only half-convinced. Even when the toad was found lurking in a skull which had rolled to the floor, he continued to glance about him doubtfully. "I do not think it was that," he said. "Are you sure that the door is locked?" "Try it," the astrologer answered curtly. M. de Vidoche did, and nodded. "Yes," he said. "All the same, I will get out of this, Give me the stuff, will you?"