Read it through once

Buck did not attack, but circled him about and hedged him in with friendly advances. The wolf was suspicious and afraid; for Buck made three of him in weight, while his head barely reached Buck’s shoulder. Watching his chance, he darted away, and the chase was resumed. Time and again he was cornered, and the thing repeated, though he was in poor condition, or Buck could not so easily have overtaken him. He would run till Buck’s head was even with his flank, when he would whirl around at bay, only to dash away again at the first opportunity.