What it is that now and then drives a wolf-pack mad in the dead of winter no man yet has wholly learned.

Possibly it begins with a "bad" wolf; just as a "bad" sledge-dog, nipping and biting his fellows, will spread his distemper among them until the team becomes an ugly, quarrelsome horde.

Such a dog the wise driver kills--or turns loose.
The wolves that bore down upon Le Beau's country were red-eyed and thin.

Their bodies were covered with gashes, and the mouths of some frothed blood.

They did not run as wolves run for meat.