The lamp had burned low and the fire was nearly out, yet Dr. Silence saw in a moment that the cat was in an excited state. It kneaded with its front paws into his chest, shifting from one to the other. He felt them prodding against him. It lifted a leg very carefully and patted his cheek gingerly. Its fur, he saw, was standing ridgewise upon its back; the ears were flattened back somewhat; the tail was switching sharply. The cat, of course, had wakened him with a purpose, and the instant he realised this, he set it upon the arm of the chair and sprang up with a quick turn to face the empty room behind him. By some curious instinct, his arms of their own accord assumed an attitude of defence in front of him, as though to ward off something that threatened his safety. Yet nothing was visible. Only shapes of fog hung about rather heavily in the air, moving slightly to and fro.