The sub-tropic beach comber and the picaroon acquire nasty tricks with knives, and have an uncanny skill at their use. Brice twisted to one side, with a sharp suddenness that all but threw his back out of joint. The knife whizzed through the still air like a great hornet. The breath of its passage fanned Gavin's averted face, as he wrenched his head out of its path. The collie had watched the supposed gambols of the two men with keen, but impersonal, interest. But here at last was something he could understand. Instinct teaches practically every dog the sinister nature of a thrown object. The man on the ground had hurled something at the man whom the collie had begun to love. That meant warfare. To the canine mind it could mean nothing else. And, ruff a-bristle and teeth bared, the dog flew at the beach comber. The latter had followed his throw by leaping to his feet. But, as he rose, the collie was at him. For an instant, the furry whirlwind was snarling murderously at his throat, and the man was beating convulsively at this unexpected new enemy. Then, almost before the collie could slash to the bone one of the hairy big hands that thrust him backward, Gavin Brice had reached the spot in a single bound, had shoved the dog to one side and was at the man. "Clear out, puppy!" he shouted, imperatively. "This is my meat! When people get to slinging knives, there's no more sense in handling them with gloves!" The debonaire laziness was gone from Brice's voice and manner. His face was dead-white. His eyes were blazing. His mouth was a mere gash in the grim face. Even as he spoke, he had thrust the snarling collie away, and was at the beach-comber. No longer was it a question of boxing or of half-jesting horseplay. The use of the knife had put this fight on a new plane. And, like a wild beast, Gavin Brice was attacking his big foe. But, unlike a wild beast, he kept his head, as he charged. Disregarding the menace of the huge arms, he came to grips, without striking a single blow. Around him the beach-comber flung his constricting grasp. But this time the grip was worthless. For, Brice's left shoulder jutted out in such manner as to keep the arms from getting their former hold around the body itself, and Brice's right elbow held off the grip on the other side. At the same time the top of Brice's head buried itself under the beachcomber's chin, forcing the giant's jaw upward and backward. Then, safe inside his opponent's guard, he abandoned his effort to stave off the giant's hold, and passed his own arms about the other's waist, his hands meeting under the small of the larger man's back. The beach comber tried now to use his freed arms to gain the grip that had once been so effective. But his clasp could close only over the slope of Brice's back and could find no purchase.