Midway through the novel, Mrs. Bowles, a woman caring for orphaned fever victims, observes that the outbreak “‘seem[s] to bring out the best and worst in the people around us’” (114). Anderson uses the “‘trying times’” (114) of the epidemic as a commentary on human beings’ reactions to calamity on a massive scale and human nature as a whole. While the novel includes many examples of both selflessness and cruelty, the author focuses on humans who choose to care for others despite their own suffering.

The human instinct to protect oneself above others is highlighted the moment yellow fever arrives in Philadelphia: the wealthy “‘fle[e] to their country estates’” (60) while the poor who’ve contracted the fever lie on the floor of a vacant building “‘with little water and no care’” (59). Matilda witnesses the effect of human selfishness after she and Grandfather head to the countryside with a farmer and his family. When the farmer learns that Grandfather, who appears sickly, won’t be allowed through a town, the farmer is so desperate to get through with his own family that he throws Matilda and Grandfather onto the road and drives off, not even bothering to give them their food and luggage.