He heard a sharp exclamation from the rider--he felt the tug as the right foot of Perris hung in the stirrup, then the stunning impact on the ground. To make sure of his prey he whirled himself to the left, but even so his striking feet did not reach the Great Enemy. Perris had freed himself in the last fraction of a second and pitching headlong from the saddle he rolled over and over in the dirt, safe. That fall opened a new hope to Alcatraz. Had he possessed his full measure of agility he would have gained his feet and rushed the man, but the long struggle had taken the edge from his activity and as he lunged up he saw Perris, springing almost on all-fours, animal-like, leap through the air and his weight struck home in the saddle. Quick, now, before the Enemy gained a secure hold, before that reaching foot attained the other stirrup, before the proper balance was struck! Up in the air went the chestnut--down on one stiff foreleg and with a great swelling of the heart he felt the rider slump far to one side, clinging with one leg from the saddle, one hand wrapped in the flying mane. Now victory with a last effort! Again he leaped high and again struck stiffly on the opposite foreleg; but alas! that very upward bound swung Perris to the erect, and with incredible and catlike speed he slipped into the saddle. He received the shock with both feet lodged again in the supporting stirrups. The frenzy of disappointment gave Alcatraz renewed energy. It was not sun-fishing now, but fence-rowing, cross-bucking, flinging himself to the earth again and again, racing a little distance and stopping on braced legs, sun-fishing to end the programme. As he fought he watched results. It was as though invisible fists were crashing against the head and body of the unfortunate rider. From nose and ears and gaping mouth the blood trickled; his eyes were blurs of red; his head rolled hideously on his shoulders. Ten times he was saved by a hair's-breadth from a fall; ten times he righted himself again and a strange and bubbling voice jerked out defiance to the horse. "Buck--damn you!--go it, you devil--I'll--beat--you still! I'll break you--I'll--make you come--when I whistle--I'll make you--a--lady's hoss!"' Consuming terror was in the stallion and the fear that, incredible as it seemed, he was being beaten by a man who did not use man's favorite weapon--pain. No, not once had the cruel spurs clung in his flanks, or the quirt whirred and fallen; not once, above all, had his mouth been torn and his jaw nearly broken by the wrenching of a curb. It came vaguely into the brutes' mind that there was something to be more dreaded than either bit, spur, or whip, and that was the controlling mind which spoke behind the voice of Perris, which was telegraphed again and again down the taut reins. That fear as much as the labor drained his vigor.