What is a quote from The Great Gatsby on illegal business being conducted?

In chapter seven, Tom Buchanan confronts Jay Gatsby with the information he received from a private investigator he hired to learn about Gatsby's criminal activities. Tom explains to Nick, Jordan, and Daisy that Gatsby and Meyer Wolfsheim bought small drugstores in New York and Chicago and "sold grain alcohol over the counter." Gatsby does not deny it, responding, "What about it?"

Tom threatens to carry his investigation further, implying that Gatsby and Wolfsheim have been engaged in a gambling racket and something bigger that one of his sources, Walter Chase, is afraid to divulge. Once again, Gatsby is unmoved by Tom's threats and accusations, replying, "You can suit yourself about that, old sport." He also points out to Tom that Walter Chase, though a friend of Tom Buchanan, was willing to join him in the bootlegging enterprise.