White Fang by Jack London

The months came and went. There was plenty of food and no work in the Southland, and White Fang lived fat and prosperous and happy. Not alone was he in the geographical Southland, for he was in the Southland of life. Human kindness was like a sun shining upon him, and he flourished like a flower planted in good soil.

And yet he remained somehow different from other dogs. He knew the law even better than did the dogs that had known no other life, and he observed the law more punctiliously; but still there was about him a suggestion of lurking ferocity, as though the Wild still lingered in him and the wolf in him merely slept.