In the warmth of the fire, Kazan’s eyes slowly closed.  He slumbered uneasily, and his brain was filled with troubled pictures.  At times he was fighting, and his jaws snapped.  At others he was straining at the end of his chain, with McCready or his mistress just out of reach.  He felt the gentle touch of the girl’s hand again and heard the wonderful sweetness of her voice as she sang to him and his master, and his body trembled and twitched with the thrills that had filled him that night.  And then the picture changed.  He was running at the head of a splendid team—­six dogs of the Royal Northwest Mounted Police—­and his master was calling him Pedro!  The scene shifted.  They were in camp.  His master was young and smooth-faced and he helped from the sledge another man whose hands were fastened in front of him by curious black rings.  Again it was later—­and he was lying before a great fire.  His master was sitting opposite him, with his back to a tent, and as he looked, there came out of the tent the man with the black rings—­only now the rings were gone and his hands were free, and in one of them he carried a heavy club.  He heard the terrible blow of the club as it fell on his master’s head—­and the sound of it aroused him from his restless sleep.

He sprang to his feet, his spine stiffening and a snarl in his throat.  The fire had died down and the camp was in the darker gloom that precedes dawn.  Through that gloom Kazan saw McCready.  Again he was standing close to the tent of his mistress, and he knew now that this was the man who had worn the black iron rings, and that it was he who had beaten him with whip and club for many long days after he had killed his master.  McCready heard the menace in his throat and came back quickly to the fire.  He began to whistle and draw the half-burned logs together, and as the fire blazed up afresh he shouted to awaken Thorp and Isobel.  In a few minutes Thorpe appeared at the tent-flap and his wife followed him out.  Her loose hair rippled in billows of gold about her shoulders and she sat down on the sledge, close to Kazan, and began brushing it.  McCready came up behind her and fumbled among the packages on the sledge.  As if by accident one of his hands buried itself for an instant in the rich tresses that flowed down her back.  She did not at first feel the caressing touch of his fingers, and Thorpe’s back was toward them.

Only Kazan saw the stealthy movement of the hand, the fondling clutch of the fingers in her hair, and the mad passion burning in the eyes of the man.  Quicker than a lynx, the dog had leaped the length of his chain across the sledge.  McCready sprang back just in time, and as Kazan reached the end of his chain he was jerked back so that his body struck sidewise against the girl.  Thorpe had turned in time to see the end of the leap.  He believed that Kazan had sprung at Isobel, and in his horror no word or cry escaped his lips as he dragged her from where she had half fallen over the sledge.  He