Then the two went down together in the water.

The Indian was about to strike at him with a knife, but the lake saved him.

As the water rushed into eye, mouth and nostril the two fell apart, but Robert was able to keep his presence of mind in that terrible moment, and, as he came up again, he snatched out his own knife and struck almost blindly.
He felt the blade encounter resistance, and then pass through it.

He heard a choked cry and he shuddered violently.

All his instincts were for civilization and against the taking of human life, and he had struck merely to save his own, but almost articulate words of thankfulness bubbled to his lips as he saw the dark figure that had hovered so mercilessly over him disappear.