He did not reappear.

Instead, a long, shrill wail came wavering towards the doctor and Dan Barry.

It raised the hair on the head of the doctor and sent a chill through his veins; but it sent Whistling Dan racing towards the place behind which Black Bart had disappeared.

The doctor hurried after as fast as he might and came upon the wolf-dog making small, swift circles, his nose to the ground, and then crossing to and fro out of the circles.

And the face of the master was black while he watched.