【导读】 《野性的呼唤》，又名《荒野的呼唤》(The Call of the Wild)，是美国著名作家杰克·伦敦创作的中篇小说。该作品以一只狗的经历表现文明世界的狗在主人的逼迫下回到野蛮，写的是狗，也反映人的世界。阅读下面的节选，仔细体会该小说的主题：生命总是在不断挣扎求存的过程中获得意义与力量。
【节选】
The call of the wild
In five minutes Buck had made fourteen hundred dollars for Thornton and his friends.The money made it possible for them to travel east，where they wanted to look for a lost gold mine.Men said that this mine had more gold than any other mine in the north.Many had looked for it，and some had died looking for it.The only men who knew where it was were now dead.
Thornton，Pete and Hans，with Buck and six other dogs，started off to the east in the spring.They travelled up the Stewart River and crossed the Mackenzie Mountains.They did not move quickly；the weather was good，and the men shot animals for food when they needed it.Sometimes they travelled for a week，and sometimes they stopped for a week and searched for gold in the ground.Sometimes they were hungry，and sometimes they had lots of food.They spent all the summer in the mountains，carrying everything they needed on their backs，sometimes making boats to go down rivers or across lakes.
In the autumn they came to a strange，flat country，with many lakes.They travelled on through the winter and met nobody，but once they found an old wooden① house，with an old gun in it.
When the spring came，they found，not the lost mine，but a lake in a wide valley.Through the shallow water the gold showed like yellow butter，and here their search ended.There was gold worth thousands of dollars in the lake，and they worked every day，filling bag after bag with gold.
The dogs had nothing to do except watch the men and eat the food which the men shot for them.Buck spent many evenings sitting by the fire.
As he sat，he saw again his dream world，where the strange hairy② man sat next to him.He also heard something calling him into the forest.Sometimes，in the middle of the day，he lifted his head and listened，and then ran off into the forest.
One night he woke up and heard the call again，a long howl③.He ran into the forest，following the sound，and came to an open place in the trees.And there，his nose pointing to the sky，sat a wolf.
The wolf stopped howling and Buck walked slowly towards him.The wolf ran，and Buck followed.After a time，the wolf stopped and waited，watching Buck，ready to attack.But Buck did not want to fight，and soon the wolf realized this，and the two animals became friendly.Then the wolf started to run again，and he clearly wanted Buck to follow him.They ran for hours through the forest，and Buck remembered again his dream world where he，and others like him，had run through a much older forest.
Then they stopped to drink，and Buck remembered John Thornton.He turned and started to run back.The wolf followed him，then stopped and howled，but Buck ran on and did not turn.Thornton was eating dinner when Buck returned.Buck jumped all over him，and for two days never left his side.He followed him every where，watching him while he ate and while he slept.But after two days the call of the wild came again，and he remembered the forest and the wolf who had run beside him.
He started to sleep out in the forest at night，sometimes staying out for three or four days.Once he was away for a week，fishing and killing animals for food.He ate well，and he grew stronger and quicker and more alive.His golden brown coat shone with health as he ran through the forest，learning its every secret，every smell，and every sound.
‘He's the finest dog that I've ever seen，’ said Thornton to his friends one day as they watched Buck walking out of camp.
‘There'll never be another dog like him，’ said Pete.
They saw him walking out of camp but they didn't see the change that happened when he was inside the forest.At once he became a thing of the wild，stepping softly and silently，a passing shadow④ among the trees.
In the autumn，Buck started to see moose⑤ in the forest.One day he met a group of about twenty.The largest was two metres tall，and his antlers were more than two metres across.When he saw Buck，he got very angry.For hours Buck followed the moose；he wanted the big one，but he wanted him alone.By the evening Buck had driven the big old moose away from the others，and then he began his attack.The animal weighed six hundred and fifty kilos—he was big enough and strong enough to kill Buck in seconds.Patiently，Buck followed him for four days，attacking and then jumping away.He gave him no peace，no time to eat or drink or rest，and slowly the moose became weaker.At the end of the fourth day Buck pulled the moose down and killed him.He stayed by the dead animal for a day and a half，eating，and then turned towards camp and John Thornton.
Five kilometres from the camp，he smelt something strange.Something was wrong.He started to run.After a few hundred metres he found the dead body of Blackie，with an arrow through his side.Then he found another sledge dog，dying，with an arrow in his neck.
Buck was near the camp now，and he could hear voices singing.Then he saw the body of Hans，lying on his face，with ten or fifteen arrows in his back.Buck was suddenly filled with a wild，burning anger.
The Yeehats⑥ were dancing around the camp，when they heard a deep and terrible growling.Buck came out of the trees faster than the north wind，and threw himself on the Yeehats like a mad dog.He jumped at the first man，and tore out his throat，
