Every second of the fight Bull Hunter had followed the actions of the horse as though he were directing them from the distance with some electric form of communication and control. When Hal Dunbar with a yell of despair was flung sidewise in the saddle as Diablo bucked in mid-air, Bull Hunter knew what was coming and lurched through the line of watchers. Straight across the open space of the circle he raced as he had never run before, and while the others stood frozen, while the man with the rope tugged futilely, Bull came in front of the stallion as Diablo whirled to smash his late rider to a pulp. There was no question of Dunbar crawling out of the way. He had rolled on his back with arms outstretched, helplessly stunned. Even in the lightning speed of the action Bull found time to wonder what would be the result if the hoof of the wild horse crashed down into that upturned, handsome face, now stained with crimson and black with dust. He had no time to imagine further. Diablo, red-eyed with anger, had whirled on him and reared, and swerving from those terrible, pawing hoofs, Bull Hunter leaped in and up. His goal was not the tossing bridle rein, but the stout strap which circled the head just above the bit, and his big right hand jarred home on this goal. All his weight was behind his stiffened arm, and under the blow the stallion lurched higher. A down-sweep of a forefoot gashed Bull's shoulder and tore his shirt to shreds. But he pressed, expecting every instant the finishing blow on his head. In he went, with all his weight behind the effort, and felt the stallion stagger on his hind legs, then topple, lose balance, and fall with a crash on his side! Bull followed him in the fall, for half a step, then whirled, scooped the nerveless body of Hal Dunbar in his arms, and rushed staggering under the burden to the edge of the circle. Diablo had regained his footing instantly, but as he strove to follow, the rope had drawn taut about his throat, and he was checked. As for Bull Hunter, he laid the senseless burden down in safety, and turned toward the stallion. One haunting fear was in his mind. Had Diablo been sufficiently blinded in the excitement of the battle to fail to recognize him, or had the great horse known the hand that toppled it back? In the latter case Bull Hunter could never come near the black without peril of his life. In a gloomy quandary he stared at the trembling, shining giant, who stood with his head high and his tail flaunting, and all the fierce pride of victory in his eye. One knot of people had gathered over the fallen Hal Dunbar, but some remained, dazed and gaping, looking at the form of the conqueror. A wild temptation came to Bull to test the horse even in this crisis of excitement, with every evil passion roused in him. He stepped out again, his right hand extended, his voice soft. "Diablo!"