In Chapter 4, Effie Perine, Sam Spade's secretary, brings in Joel Cairo's calling card and hands it to her boss with the comment, "This guy is queer." Spade pretends to be interested and kiddingly says, "In with him, then, darling." He also jokes with the house detective at the Belvedere Hotel about Cairo's effeminacy.
Homosexuals were hated, mistreated, often arrested in the days of Dashiell Hammett's The Maltese Falcon, which was published in 1929. In Chapter 7, Brigid O'Shaughnessy gets into a physical battle with Cairo when she says, referring to the young gunman Wilmer Cook, "Yes, unless he's the one you had in Constantinople."
In Chapter 10, Spade confronts Wilmer Cook in the lobby of the Belvedere Hotel and asks him, "Where is he? . . . . The fairy." He is referring to Cairo. Later when he is arguing with Caspar Gutman, he says, "Keep that gunsel away from me." He is referring to Wilmer Cook with a term that means a "kept boy." He also calls him a punk many times. It is not true that Wilmer is a homosexual, since he shows that he is obviously in love with Gutman's beautiful daughter Rhea Gutman.
In Chapter 15, Sergeant Polhaus is having lunch with Spade and telling him what the police have found out about Floyd Thursby. Polhaus speaks disparagingly of women, referring to them as "twists." In the same chapter Spade says to Polhaus, referring to Cairo, "You mean a couple of high-class sleuths like you and Dundy worked on that lily-of-the-valley all night and couldn't crack him/'
Cairo gets the most abuse. Spade knocks him unconscious in his office, slaps him around in his apartment, manhandles him some more in the final chapters in his apartment. He has reasons for doing this, but he obviously dislikes Cairo for being a homosexual.
These are the main examples of prejudice in the novel.