Suddenly the collie uttered a poignant short bark and leaped heavily to one side. His bared teeth traced a line of whiteness through the gloom. The next instant he dashed past his master’s legs, almost upsetting his balance, and shot out into the room, where he went blundering wildly against walls and furniture. But that bark was significant; the doctor had heard it before and knew what it meant: for it was the cry of the fighter against odds and it meant that the old beast had found his courage again. Possibly it was only the courage of despair, but at any rate the fighting would be terrific. And Dr. Silence understood, too, that he dared not interfere. Flame must fight his own enemies in his own way.