The story is about the trial of some corrupt cops in Memphis. Testimony about a gambling bust they were involved in is transcribed:
Mr. Stonebraker, a detective, testified that the machine found on Horton [a gambler] was called a gun, and was used by a certain class of gamblers to cheat by giving themselves big hands of cards. He explained now the swindle was practiced by such scoundrels as used this machine.
Later on:
Major Yowlell testified that the machine found on Horton was one used by gamblers to cheat at cards.