muscles writhing and knotting like live things under the silky fur. His great chest was low to the ground, his head forward and down, while his feet were flying like mad, the claws scarring the hard-packed snow in parallel grooves. The sled swayed and trembled, half-started forward. One of his feet slipped, and one man groaned aloud. Then the sled lurched ahead in what appeared a rapid succession of jerks, though it never really came to a dead stop again...half an inch...an inch... two inches... The jerks perceptibly diminished; as the sled gained momentum, he caught them up, till it was moving steadily along.

Men gasped and began to breathe again, unaware that for a moment they had ceased to breathe. Thornton was running behind, encouraging Buck with short, cheery words. The distance had been measured off, and as he