Wharton's story contains several tone shifts.
1. At the beginning of "Roman Fever," Wharton is reminiscent. She might even imagine herself as Mrs. Slade or Mrs. Ansley. The two women enjoy their vacation remembering back to when they were their daughter's age, attracting suitors and commanding attention.
2. Throughout the whole story, Wharton is critical of Old New York society. As she describes the two middle-aged women, she provides their thoughts about one another and, in doing so, illustrates their condescending, self-righteous attitudes toward one another even though they proclaim themselves "friends." Wharton's description of the widows' plights following their husbands' deaths adds to her social critique. The author stresses that the women feel lost in society without their husbands and struggle to find a purpose in life.
3. Finally, at the story's end, Wharton's tone is revealing. In having Mrs. Slade expose her plot against Mrs. Ansley all those years ago, the author depicts the lengths that women will go to in order "to keep their man." However, the story's end is full of revelations, the most shocking of which is that Mrs. Ansley did meet Mrs. Slade's future husband all those years ago and had a child with him--Barbara.
All of Wharton's various tones contribute to her purpose in exposing the underbelly of "aristocratic" Old New York. The author adeptly demonstrates in this story and The Age of Innocence that the seething emotions under the starched and corseted members of her society eventually surface and reveal their true character.