ight in the gloaming of his ancient enemy,
his hackles had risen very stiffly, his pendent lips had twitched
ominously.

Jan was perfectly well aware that the killing of Sourdough or any other
dog he had seen since his return to cities would be a supremely easy
matter for him. Indeed it would be for almost any dog having his
experience of the wild. And having in his simple dog mind no shadow of a
reason for sparing Sourdough, of all creatures that walked, one may take
it that Jan savored with some joyousness the prospect of the killing
which Sourdough's snarling rush presented to him.

He received that rush with a peculiar screwing thrust of his left
shoulder, the commonest trick among fighting-dogs in the northland, but
one for which old Sourdough seemed totally unprepared, since he made no
apparent preparation to withstand it, and as an inevitable consequence
was rolled clean over on his back by the force of his own impetus,
scientifically met.

That, by all the rules in the northland game of which Jan was a
past-master, brought Sourdough within seconds of his end. The throat was
exposed; the deadly underhold, given which no dog breathing could evade
Jan.

And at that moment came Dick's voice in very urgent and meaning
exhortation:

"Back, Jan! Don't kill him. He's too old. Back--here--Jan!"

Jan's jaws had parted for the killing grip. His whole frame was
perfectly poised for the thrust from which no dog placed as Sourdough
was could possibly escape. A swift shudder passed through him as though
his sovereign's words reached him on a cold blast, and, stiff-legged,
wondering, his shoulder hair all erect, and jaws still parted for the
fray, Jan stepped back to Dick's side.

"You'll have to keep that old tough in to heel if you mean to save him,
Sergeant," said Captain Arnutt. "You can't expect Jan to lie down to
him. Why don't you keep him in to heel, man?"

The sergeant passed on, saluting, without a word. Doubtless he had
liefer far that Captain Arnutt had hit him in the face. But, when all is
said, no words could hurt this curious monomaniac now, after that which
he had seen with his own eyes and that which he now saw.

Complete enlightenment had come to old Sourdough in one fraction of a
moment. In the moment when he reached earth, on his back, flung there by
his impact with the calculated screwing thrust of Jan's massive
shoulder, Sourdough knew that his day was over. He expected to die then
and there, a