Study on the Causes of Buck’s Returning the Wild摘要：本文运用马克思主义辩证关系原理，科学地探索了巴克回归自然的内因和外因，并对人类进行了深刻的反思。

淘金热是巴克转变的一个间接原因，也是一个大背景。

巴克凭着先天优势在残酷的不断变化的环境中，学得了重要的生存法则，即“适者生存”。

由此发现，虽然外部环境在不断变化，但巴克凭着自己的能力掌握规律，以另一种方式生存。

这表明外因在一定程度上影响了事物的发展，而事物的发展是由内因决定的。

关键字：内因;外因；生存法则；适应能力。

Abstract: On the basis of Marxist dialectic, this passage makes a study on the internal and external causes of buck’s returning to the wild, and makes a reflection of human beings as well. Prevailing phenomenon of seeking gold is an indirect cause as well as a big backdrop of the time. Buck, learning against his superior advantages, learned a critical law of existence, that is, survival of the fittest. In this sense, in spite of the various environments, Buck mastered the law against his own adaptability and led a different way of life. That indicates the external causes have an effect on the development of things, while it is the internal cause that decides the final implementation of things.Key words: external causes; internal causes; law of existence; adaptability1.Introduction:The call of the wild, one of the representative works, written by Jack London, reveal many realities and truths that deserve ponder and study. On the ground of Marxist dialectic, we choose to the causes, internal and external, that push Buck to return to the wild. Any implementation of phenomenon is formed by the combined effect of internal and external causes, thus, to know the process and results of development in things, finding out the reasons is necessary. At the same time, thoughts should not be confined in things themselves, but touch the lessons and experience hiding in the development of things, that is, in the call of the wild, we should see the illumination from Buck’s shift of life, and make self-reflection. In this sense, reflection on human beings being the third part of this passage, apart from external causes and internal causes.2.External Causes2.1 The Found of Yellow MetalIt is a direct reason that leads to Buck´s hardship. It is the found of gold that increase the demand for dogs of strong muscle and long hair, which can according make them pull sled protect them from frost. Also it is the found that offers Manuel, one of the gardener´s helpers an opportunity to reduce his debt, that is to sell Buck. Buck was betrayed and forced to begin his shift of life.2.2.The Big Contrast in Living ConditionsBuck had lived the sun-kissed santé clara valley，where was beautiful and peaceful. “It stood back from the road, half-hidden among the trees, through which glimpses could be caught of the wide cool veranda that ran round its four sides. The house was approached by graveled drive ways which wound about through wide spreading lawns and under the interlacing boughs of tall poplars. Atthe rear things were on even a more spacious scale than at the front.” .“T here were great stables, where a dozen grooms and boys held forth, rows of vine-clad servants’ cottages, an endless and orderly array of outhouses , long grape arbors, green pastures, orchards, and berry patches.”And there he got well along with people, especially his little masters. “He plunged into the swimming tank or went hunting with the Judge’s sons; he escorted Mollie and Alice, the Judge’s daughters, on long twilight or early morning rambles; on wintry nights he lay at the Judge’s feet before the roaring library fire; he carried the Judge’s grandsons on his back, or rolled them in the grass, and guarded their footsteps through wild adventures down to the fountain in the stable yard, and even beyond, where the paddocks were, and the berry patches.”Besides, he enjoyed a fine pride there, “Among the terriers, he stacked imperiously, and Toots, and Ysabel he utterly ignored for he was king-----king over all creeping, crawling, flying things of Judge Miller’s place, humans included.”But after his leaving, he never enjoyed the happiness dignity as well as pride in high position. The snow-covered world was crude, chilly, and miserable, and Buck, as equally as other dogs, had to confronted that, and bore the pain of fresh and spirit that was beyond imagination.“Once the sled broke through , with Dave and Buck, and were half-frozen and all but drowned by the time they were dragged out. The usual fire was necessary to save them. They were coated solidly with ice, and the two men kept them on the run around the fire, sweating and thawing, so close that they were singed by the flames.”Not only did torture him, but also, worse, the merciless humankind who offered no adequate food, while drove the dogs to continuously proceed for miles and miles. At best, like Francois, who rubbed Buck’s soft feet and make moccasins for Buck. At least, like Mercede, who plus the weight of the sled without considering the dogs.“Again Hal’s whip fell upon the dogs. They threw themselves against the breastbands, dug their feet into the packed snow, got down low to it, and put forth all their strength. The sled held as thought it were an anchor. After two efforts, they stood still, panting. The whip was wrestling savagely.”Furthermore Buck had to cope with the clashes occurred among huskies or between them and the invaders against their weak condition. As time went by death was not the acquaintance. “Buck staggered over against the sled, exhausted, sobbing for breath, helpless. This was Spitz’s opportunity. He sprang upon Buck, and twice his teeth sank into his unresisting foe and ripped and tore the flesh to the bone.” All the said facts gradually dig Buck’s nature out, and make him a beast step by step.2.3 The Death of ThorntonThe Death of Thornton is the most direct reason of Buck’s backing to the wild. Thornton saved buck, and buck was more than grateful for him, but loved him. Buck was content to adore at a distance. He would lie by the hour, eager, alert, at Thornton’s feet, looking up to his face, upon it studying it, following with keenest interest each fleeting expression, every moment or change of feature. Or, as chance might have it, he would lie farther away, to the side or rear, watching theoutlines of the man and the occasional movements of his body. Thornton was the very master in his ideal. And it was Buck’s love for Thornton that left the wild suspended. despite his beast impulse was in summit. “ But as often as he gained the soft unbroken earth and the green shade, the love for John Thornton drew him back to the fire again.”“Thornton alone held him. The rest of mankind was as nothing.” Therefore, when Thornton died, Buck despaired to death, and entered into the wild without any nostalgia.3．Internal Causes3.1. The Strain of BuckBuck’s ancestors were wolves，known as fierce savage and crude，while in Buck’s gene，those features had been hid since his ancestors were trained by human beings. At the beginning，not only did he hatred men，but trust in them。