A very desperate vigor stirred in Sourdough’s limbs as he took the course which is only taken at critical moments.  He deliberately turned farther on his back—­the position of all others most dreaded—­in order to bring his feet into play, his jaws being momentarily helpless.  His abdominal muscles were in splendid order.  Like a lynx, Sourdough drew in and up his powerful hind quarters, and, as if they had been a missile launched from a catapult, slashed his two hind feet along Jan’s belly, as a carpenter might rip a board down with a chisel.

In that same moment Sergeant Moore stepped forward, with a hoarse cry: 

“Here, damme!” he shouted at O’Malley, “you’d better haul off your captain’s dog, or—­or mine’ll kill him!”

And with a resounding thwack he brought his riding-cane down across Jan’s forehead.  It was this, rather than his own very serviceable two chisels, that brought the husky sudden release from the grip upon his neck, which, already deep-sunk, had been like to finish his career.  The high-crowned shape of Jan’s skull, and the soft fineness of the skin and hair that covered it, made him very sensitive to a blow on the head.  Also he knew it was a man’s attack, and not a dog’s.  When he saw who the man was, he roared at him very ferociously.  And that was the first occasion upon which Jan had ever shown his teeth in real anger to a human.

Had not Sourdough been there, it is hard to say what might have happened.  As it was, the sergeant’s intervention and Jan’s angry response thereto gave Sourdough the opportunity he had longed for.  It gave him, in safety, the rush at Jan from the side.  It would have availed him little if Jan had seen him coming.  But Jan, engaged in threatening his human enemy, saw nothing till the tremendous impact of Sourdough’s rush took him off his feet, and the husky got, not precisely the true throat-hold he wanted, but a deadly hold, none the less, in the flesh of Jan’s dewlap.

The position of a few seconds earlier had been practically reversed.  Jan’s blood was running between Sourdough’s fangs now—­a fiery tonic, and veritable eau-de-vie to the husky.  Sourdough’s catlike tactics—­perhaps the best and safest in such a case—­were not adopted by Jan, who never yet had used such a method.  With a huge effort the hound managed to twist his body in such a way as to gain foothold for his hind feet; and then, by the exercise of sheer muscular strength, he curved his neck and shoulder inch by inch (while still his blood slaked Sourdough’s thirst) until with sudden swiftness he was able to grip the husky’s near fore leg between his jaws, just on and below the knee.

Then Jan concentrated his whole being into the service of his jaws.  Sourdough gave a cry that was almost a scream, and his jaws flew apart, dripping Jan’s blood.  Jan’s teeth sank a shade deeper.  Sourdough pivoted round in agony, snapping at the air, and emitting an unearthly yowling, snarling, grunting cry the while.  Jan’s teeth locked together, and then were sharply withdrawn, leaving a very thoroughly smashed and punctured fore leg to dangle by its skin and sinew.