James Cagney states, as Lefty Merrill: "What do I know about grapefruit? I never even saw a grapefruit!" One of Cagney's best known scenes is smashing a grapefruit into Mae Clarke's face in The Public Enemy (1931).
There is no accounting for nicknames, but "Lefty" Merrill writes and drinks with his right hand.
The uncredited character "Ralph Blackman - band leader" is a parody of the famous bandleader Paul Whiteman.