Found in The City of Fire
Written by Jack London
His first great success and his last were dog stories. These were full-length novels. "The Call of the Wild" is a biological study in reversion to type, where the domesticated dog returns to the wild.
The hero of "TheCall of the Wild" is a dog with wolf blood, who goes from a home where he is loved and petted, through experiences of hardship and brutality, back to the life of the wilderness.