| Quote #4
For the most part, however, Buck's love was expressed in adoration. While he went wild with happiness when Thornton touched him or spoke to him, he did not seek these tokens. Unlike Skeet, who was wont to shove her nose under Thornton's hand and nudge and nudge till petted, or Nig, who would stalk up and rest his great head on Thornton's knee, Buck was content to adore at a distance. He would lie by the hour, eager, alert, at Thornton's feet, looking up into his face, dwelling upon it, studying it, following with keenest interest each fleeting expression, every movement or change of feature. Or, as chance might have it, he would lie farther away, to the side or rear, watching the outlines of the man and the occasional movements of his body. And often, such was the communion in which they lived, the strength of Buck's gaze would draw John Thornton's head around, and he would return the gaze, without speech, his heart shining out of his eyes as Buck's heart shone out. (6.6)
In the intensity of their relationship, Buck and Thornton have a unique interaction that eclipses that of the other dogs.
| Quote #5
For Thornton, however, his love seemed to grow and grow. He, alone among men, could put a pack upon Buck's back in the summer traveling. Nothing was too great for Buck to do, when Thornton commanded. One day (they had grub-staked themselves from the proceeds of the raft and left Dawson for the head-waters of the Tanana) the men and dogs were sitting on the crest of a cliff which fell away, straight down, to naked bed-rock three hundred feet below. John Thornton was sitting near the edge, Buck at his shoulder. A thoughtless whim seized Thornton, and he drew the attention of Hans and Pete to the experiment he had in mind. "Jump, Buck!" he commanded, sweeping his arm out and over the chasm. The next instant he was grappling with Buck on the extreme edge, while Hans and Pete were dragging them back into safety. (6.13)
Buck’s loyalty to Thornton is blind – such emotion is dangerous, and its threat to Buck’s life is counter to the survival – given laws he learned in the North.
| Quote #6
Thornton knelt down by Buck's side. He took his head in his two hands and rested cheek on cheek. He did not playfully shake him, as was his wont, or murmur soft love curses; but he whispered in his ear. "As you love me, Buck. As you love me," was what he whispered. Buck whined with suppressed eagerness. (6.48)
Buck’s emotional love for Thornton overcomes physical tests.