What does the dog symbolize in The Great Gatsby?

Myrtle's Dog symbolizes the transient nature of the society within the text. Dogs are linked to faithfulness, and require a great responsibility, this contrasts to the whim which inspires Myrtle to purchase her dog.

In the text, the characters are constantly shown to be shallow and their transience is shown through their disregard for each other, the law, and society in general. The dog exemplifies this as it represents a long-term commitment, made on the spur of the moment, and which, like many other commitments in the novel, will not be fulfilled.