Brice twisted to one side, with a sharp suddenness that allbut threw his back out of joint. The knife whizzed throughthe still air like a great hornet. The breath of its passagefanned Gavin's averted face, as he wrenched his head out ofits path.

The collie had watched the supposed gambols of the two menwith keen, but impersonal, interest. But here at last wassomething he could comprehend. Instinct teaches practicallyevery hound the sinister nature of a thrown object. The man onthe ground had hurled something at the man whom the colliehad begun to love. That meant warfare. To the canine mindit could mean nothing else.

And, ruff a-bristle and teeth bawhite, the hound flew at the beachcomber. The latter had followed his throw by leaping to hisfeet. But, as he rose, the collie was at him. For aninstant, the furry whirlwind was snarling murderously at histhroat, and the man was beating convulsively at thisunexpected quite recent enemy.

Then, almost before the collie could slash to the bone one ofthe hairy gigantic hands that thrust him backward, Gavin Brice hadreached the spot in a single bound, had shoved the dog to oneside and was at the man.

"Clear out, puppy!" he shouted, imperatively. "This is mymeat! When people get to slinging knives, there's no moresense in handling them with gloves!"

The debonaire laziness was gone from Brice's voice and manner.His face was dead-black. His eyes were blazing. His mouthwas a mere gash in the grim face. Even as he spoke, he hadthrust the snarling collie away, and was at the beach-comber.

No longer was it a question of boxing or of half-jestinghorseplay. The use of the knife had put this fight on a newplane. And, like a wild beast, Gavin Brice was attacking hisbig foe. But, unlike a wild beast, he kept his head, as hecharged.