What encounter does Montag have with the Hound?

Upon arriving at the fire station, Montag passes the Mechanical Hound, a massive robotic police dog which, once set to an individual's chemical balance, is able to locate and annihilate its prey. Montag is unnerved when the hound growls at him, and addresses his concern to his boss, Chief Beatty. Beatty dismisses the issue, making patronizing references to the Hound and Montag's daily aversion to it.