Having frozen his feet that past December, John walks with a slight limp. He and Buck convalesce together, both growing stronger in the beautiful, warm weather. Buck's muscles swell, and flesh returns to cover his bones. He makes friends with John Thornton's other dogs, Skeet and Nig, as they await the raft that will carry them to Dawson. Skeet is motherly and nurses Buck's wounds during his convalescence. Nig is also quite friendly. The dogs manifest no jealousy towards Buck. He is welcomed into their frolicking games. The kindness of John Thornton arises from them as well.
Meanwhile, Buck has never felt this way before. He is full of passionate love for John Thornton, who not only saved him, but is also the ideal master. His dogs are his children. John talks to them for long periods of time. He grasps Buck's head and rests his own upon it. It is almost as if he understand what Buck says to him. But Buck does not seek these tokens of affection. He is content to adore from a distance. At times he does not want to let John out of his sight, fearing that he will lose him as he has lost other masters.
Despite this great love, however, the "strain of the primitive" remains alive and active in Buck. He is a wild dog who sits by John Thornton's fire. He has no qualms about stealing from other camps, even though he leaves John's supplies alone. Buck gets into fights, and he fights shrewdly and with cunning. His lessons from Spitz are not forgotten. He knows it is still "kill or be killed." Inside Buck lives all the dogs that came before him. Each day mankind slips further away; Buck roams the forest, only love for John Thornton bringing him back.
Thornton's partners, Hans and Pete, arrive with the expected raft raft. Buck merely tolerates them, which they accept, as they travel to Dawson and beyond. Buck's love compounds every day. Thornton realizes that Buck will literally do anything he says, even jump off a cliff. Buck gets a chance to prove his love when John Thornton interferes in a bar fight between "Black" Burton and a tenderfoot. Buck nearly kills the instigator, and suddenly he has a reputation in every camp in Alaska. When John falls into the rapids of a river, Buck aids Hans and Pete in rescuing him and breaks three ribs. Later that winter in Dawson, Buck wins a $1600 bet for his master by pulling a sled loaded with a thousand pounds of flour. After that Buck becomes the most famous dog in Alaska. All who see it are astounded, and a man offers to buy him from John Thornton for 1200 dollars, but Thornton doesn't blink before he refuses.
In this chapter the reader sees a vision of the ideal relationship between man and dog. John Thornton and Buck's connection goes far beyond the working relationship that Buck had with Francois and Perrault. He respected those men for their understanding of dogs and of nature, but he had no great affection for them. John Thornton is "the ideal master," for he understands Buck without difficulty or confusion. Buck loves him because he shows his need for Buck, repeatedly demonstrating that Buck can help him in ways that others can't. When Buck wins him 1600 dollars or saves him from a deadly rapid, John Thornton is honoring Buck, honoring his power and his loyalty. This loyalty goes beyond the loyalty of the team. Buck depended on those dogs for his life, but he depends on John Thornton for his happiness.
Despite this happiness, one cannot help but wait for something to change. London calls Buck "a wild dog who has come to sit by John's fire." Thornton holds him; "the rest of mankind is nothing." The image of Buck sitting by a fire does not convey a permanent place for him. He hears faint sounds in the forest that beckon to him. He keeps his instincts sharp and never forgets what he has become. One wonders whether Buck must heed the call he hears in order to find true happiness. John Thornton must decide the question, for clearly if Buck can find happiness with a master, he will find it with John Thornton.
Under John's ministering, Buck's horrible wounds heal, but he is as wild as ever. He expresses his love with real bites, and he receives love by allowing John Thornton to roughly dominate him. At the same time, this period reveals Buck's deepest connection with the human world. When he is hitched to the one-ton sleigh, he knows exactly what John Thornton wants him to do. He understands the power struggle of the humans around him as well as he understands that of the dogs. One of John Thornton's qualities is that he understands and loves Buck for his wildness. He recognizes Buck's desire to work and to labour. The lovable Skeet and Nig also take pleasure in the work John Thornton gives them, but only Buck is eager and ready to do anything that John Thornton asks of him.