在小说第一章开始部分，作者引用诗人John Myers O’Hara 的诗Atavism,此诗作用是领起全文，暗示故事的发展方向和主角巴克克的命运，十分重要。Atavism: “Old longings nomadic leap, Chafing at custom’s chain; Again from its brumal sleep, Wakens the ferine strain.” 小说第六章For the Love of A Man 的其中一段描写,刻画了巴克对主人约翰·桑顿特殊的感情表达方式——不求时时亲近，只须守 护主人左右。而主人似乎也能感受到巴克的灵性，人与狗之间有了近乎神奇的默契。此段堪 称心理描写的神来之笔： 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. ... 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, ... 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.
Love, genuine passionate love, was his for the first time.(爱，真正的充满激情的爱，第一次出现在他心里。)Mercy did not exist in the primordial life. It was misunderstood for fear, and such misunderstandings made for death. Kill or be killed, eat or be eaten, was the law.(在原始社会中不存在仁慈。仁慈会被误解为畏葸，而这种误解能导致死亡。杀，或是被杀；吃，或是被吃，这就是法律。)He linked the past with the present, and the eternity behind him throbbed through him in a mighty rhythm to which he swayed as the tides and reasons swayed.(他连接了古代和此刻，他身后的永恒以强有力的节奏在他体内搏动，他也随着潮流和季节的律动而律动。)It filled him with a great unrest and strange desires. It caused him to feel a vague, sweet gladness, and he was aware of wild yearings and strings for he knew not what.(那呼唤用一种巨大的不安和奇怪的欲望充满了他的心，让他感到一种模糊而甜蜜的欢乐，使他意识到了种种狂野的渴望和激动，追求着某种他所不知道的东西。)