" In 1846, a Danish physician named Peter Panum witnessed a measles epidemic on the Faroe Islands, a remote archipelago north of Scotland, and drew some keen inferences about how the ailment seemed to pass from person to person, with a delay of about two weeks (what we’d now call an incubation period) between exposure and symptoms. "

― David Quammen , Spillover: Animal Infections and the Next Human Pandemic