He sat at the upper end of the room, gazing blankly through the doorway at the gray light and clouds of white mist trailing. Once an object came into the field of his vision. At the first glimpse he thought it a dog--long, lean, skulking, prowling, tawny--on the scent of his tracks. Then the mist passed over it. When he beheld it again it had approached nearer and was creeping rapidly toward the door. His listless eyes grew fascinated by its motions--its litheness, suppleness, grace, stealth, exquisite caution. Never before had he seen a dog with the step of a cat. A second time the fog closed over it, and then, advancing right out of the cloud with more swiftness, more cunning, its large feet falling as lightly as flakes of snow, the weight of its huge body borne forward as noiselessly as the trailing mist, it came straight on. It reached the hickory block, which formed the doorstep; it paused there an instant, with its fore quarters in the doorway, one fore foot raised, the end of its long tail waving; and then it stole just over the threshold and crouched, its head pressed down until its long, whitish throat lay on the floor; its short, jagged ears set forward stiffly like the broken points of a javelin; its dilated eye blazing with steady green fire--as still as death. And then with his blood become as ice in his veins from horror and all the strength gone out of him in a deathlike faintness, the school- master realized that he was face to face unarmed with a cougar, gaunt with famine and come for its kill.