The elderly mountain lion which, for years, had made his winter abode in the cave, had dropped down over the ledge, from his summer and autumn wanderings in the rich hunting grounds among the higher reaches of the peak. A warm reek of delicious live mutton assailed his hungry senses as he neared his home. Then, of a sudden, out of the doorway of the lair flashed something hostile and furious; charging straight at him before the lion could so much as crouch for a spring. Treve carried the battle to the enemy, ere the latter knew there was such a thing as a foe between him and the sheep whose stronger odor had stifled the scent of the collie. With hurricane speed he dashed at the approaching beast. The lion reared on his hind legs, spitting, snarling, swatting with both murderous forepaws. But, by reason of the attack’s complete surprise and a season of heavy feeding and his advancing years, he was slow. The dog was able to dive beneath the flailing claws, slash the unprotected underbody, and spring to one side. The lion swerved, to follow. But Treve was of a breed whose ancestors were wolves;--a breed whose brain never quite loses, at emergency, the wolf-cunning. A million times, in the world’s earlier centuries, had panther and wolf done death-battle in prehistoric forests. Their warfare was a phase of the eternal cat-and-dog feud. Some native ancestral skill guided Treve, to-night. For, as he swerved, he twisted back, with the speed of thought. The mountain lion lunged after him. The collie was no longer there. Instead, his white fangs had found the mark that instinct taught them to seek. They closed on the nape of the lion’s neck, as the old cat shifted his head in pursuit of his dodging foe. The lion thrashed madly about to dislodge the jaws that were grinding unrelentingly toward his spinal cord. He tossed the dog to and fro. He banged him against the ground and against the cliffside. Once his curved claws raked Treve obliquely, shearing to the bone. But the dog hung on; ever deepening his bite into the neck-nape. He was knocked breathless. He was in torment. But he hung on. He redoubled the muscular pressure of his grinding jaws. It was his only chance. And he knew it. Then, with a last frantic plunge, the lion flung him off. The dog’s whirling body crashed athwart the cliffside. Treve fell breathless and stunned to the ground; and lay there. The lion did not follow up his victory, but lay where he had fought. He twisted and writhed like a broken snake. That last irresistible fling had been his death-struggle. The collie’s teeth had found their unerring way to the spinal cord. When, at last--battered and bruised and bleeding--the collie staggered to his feet, the enemy sprawled inert and lifeless, ten feet away from him; and the cave was reverberant with the bleating of panic sheep.