Metaphor

A figure of speech that makes a direct comparison between two unlike things. A metaphor suggests that one thing IS another thing, or is equal to another thing.

Example From Text

Thus, as token of what a puppet thing life is, the ancient song surged through him and he came into his own again; and he came because men had found a yellow metal in the North, and because Manuel was a gardener's helper whose wages did not lap over the needs of his wife and divers small copies of himself.

Explanation

London uses the metaphor of a puppet to describe Buck's life because a puppet is controlled by the puppeteer. The image helps readers understand that Buck's life has changed utterly because of forces outside of his control: the Gold Rush; and Manuel's financial hardship and willingness to steal Buck to make money.