Rex cleared his mouth of the impeding hair and flew at Lad once more--before the old dog had fairly gotten to his feet, but not before the line of defense had been thought out. Lad half wheeled, dodging the snapping jaws by an inch and taking the impact of the charge on his left shoulder, at the same time burying his teeth in the right side of Rex's face. At the same time Lad gave ground, moving backward three or four yards, helped along by the impetus of his opponent. Home was a half-mile behind him, in an oblique line, and he could not turn to gauge his direction. Yet he moved in precisely the correct angle. (Indeed, a passer-by who witnessed the fight, and the Master, who went carefully over the ground afterward, proved that at no point in the battle did Lad swerve or mistake his exact direction. Yet not once could he have been able to look around to judge it, and his foot-prints showed that not once had he turned his back on the foe.) The hold Lad secured on Rex's cheek was good, but it was not good enough. At thirteen, a dog's "biting teeth" are worn short and dull, and his yellowed fangs are blunted; nor is the jaw by any means as powerful as once it was. Rex writhed and pitched in the fierce grip, and presently tore free from it and to the attack again, seeking now to lunge over the top of Lad's lowered head to the vital spot at the nape of the neck, where sharp teeth may pierce through to the spinal cord. Thrice Rex lunged, and thrice Lad reared on his hind legs, meeting the shock with his deep, shaggy breast, snapping and slashing at his enemy and every time receding a few steps between charges. They had left the path now, and were plowing a course through deep snow. The snow was scant barrier to Rex's full strength, but it terribly impeded the steadily backing Lad. Lad's extra flesh, too, was a bad handicap; his wind was not at all what it should have been, and the unwonted exertion began to tell sharply on him. Under the lead-hued skies and the drive of the snow the fight swirled and eddied. The great dogs reared, clashed, tore, battered against tree-trunks, lost footing and rolled, staggered up again and renewed the onslaught. Ever Lad manoeuvered his way backward, waging a desperate "rear-guard action." In the battle's wake was an irregular but mathematically straight line of trampled and blood-spattered snow. Oh, but it was slow going, this ever-fighting retreat of Lad's, through the deep drifts, with his mightier foe pressing him and rending at his throat and shoulders at every backward step! The old dog's wind was gone; his once-superb strength was going, but he fought on with blazing fury--the fury of a dying king who _will_ not be deposed.