Letter Gone Wrong
When Alida and Grace are young girls, they are both in love with Delphin Slade, who proposes to Alida. Inspired by the story of a woman who sent her sister out into the cold to catch Roman fever -- or malaria -- to eliminate her as a rival for another man's affections, Alida writes a letter to Grace pretending to be Delphin and asking her to meet at the Coliseum for a rendezvous. Alida thinks that Grace will go and become ill from waiting in the cold -- though she says she never wanted for Grace to die. However, Alida does not count on Grace answering the letter. The irony is that the letter that was meant to keep Delphin and Grace apart actually brought them together. Without the letter, it is unclear if the two would have ever acted on their feelings.
Over the years, Alida has always been envious of Grace for her daughter, Barbara, whom she considers vibrant and interesting. Barbara is the daughter that Alida wishes she had, while Alida thinks her own daughter is "too perfect" and a bit dull. Alida wonders how Grace and Mr. Ansley -- two "dull" people -- could have had a daughter who was so "dynamic." The irony is not revealed until the last line of the story: Barbara is actually Delphin's daughter.
Alida Slade always considered herself to be the one with the more interesting life: She was married to a lawyer, she entertained important dignitaries, and she traveled the world. Meanwhile, she considered Grace Ansley to be the mousy and boring one. She thinks Grace is plain and looks down on her simple pursuits, such as knitting. The irony is revealed when she learns about the night that Grace spent with Delphin, as well as the secret she has been harboring all these years about Barbara's father. It turns out that Grace is actually the more interesting person who has lived with passion and intrigue.
The title itself hints at the irony of the story. The title refers to malaria, which the characters refer to as "Roman fever." When she writes the letter, Alida wants Grace to catch Roman fever -- or at least to become very ill -- while waiting for Delphin, whom Alida thinks will never come. Grace doesn't catch Roman fever, but she does experience another kind of Roman fever: lust and passion sparked by Delphin Slade.