And sixty miles farther north Kazan, night after night, gnawed at his steel chain. Night after night he had watched the stars, and the moon, and had listened for Gray Wolf's call, while the big Dane lay sleeping. Tonight it was colder than usual, and the keen tang of the wind that came fresh from the west stirred him strangely. It set his blood afire with what the Indians call the Frost Hunger. Lethargic summer was gone and the sharp-winded days and nights of hunting were at hand. He wanted to leap out into freedom and run until he was exhausted, with Gray Wolf at his side. He knew that Gray Wolf was off there--where the stars hung low in the clear sky--and that she was waiting. All that night he was restless--more restless than he had been at any time before. Once, in the far distance, he heard a cry that he thought was the cry of Gray Wolf, and his answer roused McGill from deep sleep. It was dawn, and the little professor dressed himself and came out of the cabin. With satisfaction he noted the exhilarating snap in the air. He wet his fingers and held them above his head, chuckling when he found the wind had swung into the north. He went to Kazan, and talked to him. Among other things he said: "This'll put the black flies to sleep, Kazan. A day or two more of it and we'll start." Five days later McGill led first the Dane, and then Kazan, to a packed canoe. Sandy McTrigger saw them off, and Kazan watched for a chance to leap at him. Sandy kept his distance, and McGill watched the two with a thought that set the blood running swiftly behind the mask of his careless smile. They had slipped a mile downstream when he leaned over and laid a fearless hand on Kazan's head. Something in the touch of that hand, and in the professor's voice, kept Kazan from a desire to snap at him. He tolerated the friendship with expressionless eyes and a motionless body. "I was beginning to fear I wouldn't have much sleep, old boy," chuckled McGill ambiguously, "but I guess I can take a nap now and then with you along!" For three days the journey continued without mishap along the shore of Lake Athabasca. On the fourth night McGill pitched his tent in a clump of Banksian pine a hundred yards back from the water. All that day the wind had come steadily from behind them, and for at least a half of the day the professor had been watching Kazan closely. From the west there had now and then come a scent that stirred Kazan uneasily. Since noon he had sniffed that wind. Twice McGill had heard him growling deep in his throat, and once, when the scent had come stronger than usual, he had bared his fangs, and the bristles stood up along his spine.