Being a dog from civilization, Buck's paws are not accustomed to the harshness of the trail, and François often has to bring Buck's food rations to him; finally, he makes a pair of moccasins which will fit over Buck's paws. They are a great relief to the dog. One morning, a surprising event occurs. The dog Dolly, a particularly mild-mannered dog, suddenly begins "a long, heartbreaking wolf howl," which indicates that she has suddenly gone mad. Frothing at the mouth and snarling, Dolly begins to chase Buck, who flees in confused terror from her. After plunging through the woods and through ice, with Dolly snarling only one leap behind him, Buck finally passes through the camp site, where François holds an ax, poised in his hand. Thus he does what he must: he smashes the ax down on the mad dog's head.
The incident is exhausting, and Buck staggers along the trail, completely worn out. The nasty tempered Spitz takes Buck's weakened condition as an opportunity to attack him once more, and twice he tears Buck's flesh to the bone. François, however, is close by, and using the whip, he beats Spitz away. But Buck can no longer forgive Spitz, and from this moment on, it is all-out war between Spitz and Buck. Buck constantly challenges Spitz's authority and uses every chance he can to undermine Spitz's authority. London writes that it was "inevitable that the fight for leadership should come." Buck's pride is such that he does not like to be subservient to any dog — most of all to Spitz.
All the way to Dawson, there is continual bickering between Buck and Spitz, and this conflict is important, of course, because ideally a dog team must work as a single unit, and when a dog mutinies, that dog ceases to be effective. More important, though, is London's focus on the struggle between the civilized dog from the South and the primitive dog from the North. London's point here is that the cunningness that Buck learned in civilization combined with his superior strength and his newly acquired primeval instincts make Buck the superior animal in what will be a coming, critical contest between him and Spitz.
