Wherefore, as Lad reared to meet Rex's lunge, Wolf hurled himself like a furry whirlwind upon the old dog's flank, burying his white teeth in the muscles of the lower leg. The flank attack bowled Lad completely over. There was no chance now for such a fall as would enable him to spring up again unscathed. He was thrown heavily upon his back, and both his murderers plunged at his unguarded throat and lower body. But a collie thrown is not a collie beaten, as perhaps I have said once before. For thirty seconds or more the three thrashed about in the snow in a growling, snarling, right unloving embrace. Then, by some miracle, Lad was on his feet again. His throat had a new and deep wound, perilously close to the jugular. His stomach and left side were slashed as with razor-blades. But he was up. And even in that moment of dire stress--with both dogs flinging themselves upon him afresh--he gained another yard or two in his line of retreat. He might have gained still more ground. For his assailants, leaping at the same instant, collided and impeded each other's charge. But, for the first time the wise old brain clouded, and the hero-heart went sick; as Lad saw his own loved and spoiled son ranged against him in the murder-fray. He could not understand. Loyalty was as much a part of himself as were his sorrowful brown eyes or his tiny white fore-paws. And Wolf's amazing treachery seemed to numb the old warrior, body and mind. But the second of dumfounded wonder passed quickly--too quickly for either of the other dogs to take advantage of it. In its place surged a righteous wrath that, for the instant, brought back youth and strength to the aged fighter. With a yell that echoed far through the forest's sinister silence, Lad whizzed forward at the advancing Rex. Wolf, who was nearer, struck for his father's throat--missed and rolled in the snow from the force of his own momentum. Lad did not heed him. Straight for Rex he leaped. Rex, bounding at him, was already in midair. The two met, and under the Berserk onset Rex fell back into the snow. Lad was upon him at once. The worn-down teeth found their goal above the jugular. Deep and raggedly they drove, impelled by the brief flash of power that upbore their owner. Almost did that grip end the fight and leave Rex gasping out his life in the drift. But the access of false strength faded. Rex, roaring like a hurt tiger, twisted and tore himself free. Lad realizing his own bolt was shot, gave ground, backing away from two assailants instead of one. It was easier now to retreat. For Wolf, unskilled in practical warfare, at first hindered Rex almost as much as he helped him, again and again getting in the bigger dog's way and marring a rush. Had Wolf understood "teamwork," Lad must have been pulled down and slaughtered in less than a minute.