Early on in the novel, death carts holding the corpses of cholera victims begin to pass the coffeehouse. When a cart goes by the coffeehouse holding the dead body of a man with its arm flopping over the side, Mattie's grandfather says there is "no place" for the dead up here. This turns out to be an ironic statement, as Grandfather himself will later die, his body lying in the coffeehouse. This time, when the death cart stops, it carries off Grandfather along with the two other corpses it already has picked up.
Mattie helps push the cart to the burial ground. When she realizes her grandfather is about to be dumped into an open mass grave, she insists a prayer be read.
As Anderson explains in the appendix, as with the bubonic plague in Europe, death carts wandered the streets of Philadelphia in 1793. The men pushing them called out for dead bodies. The bodies had to be disposed of to help stop the spread of the epidemic even though normal systems of dealing with the dead had broken down.
The book shows the toll the cholera epidemic took on Philadelphia at a time when medicine was still primitive and people had little idea how to battle or treat a deadly disease.