Among the books that Humbert Humbert (the narrator and main character in VN’s novel Lolita, 1955) brings Lolita, when he visits her in the Elphinstone hospital, is Clowns and Columbines:
This was Tuesday, and Wednesday or Thursday, splendidly reacting like the darling she was to some “serum” (sparrow’s sperm or dugong’s dung), she was much better, and the doctor said that in a couple of days she would be “skipping” again.