Back in the early 1800s, at the height of the age of yellow fever, New Orleanians didn’t know anything about social distancing. They didn’t know anything about N95 masks. They really didn’t even know anything about germs.

They did know that people were dying, and that something was causing it. Maybe it was bad air, or “miasma,” as it was known. Or maybe “exhalations of the dead” were to blame, some said.