As Boccaccio records the experience of the residents of Florence during the onslaught of the Black Death, he makes several intriguing observations and notes about the response of non-infected people to the spread of the pandemic. He compares religious and secular responses, discusses the ineffectiveness of doctors, explains the belief behind the carrying of sweet-smelling plants, and notes that many people became either more reclusive or more gregarious in hopes of decreasing the spread of the plague--or of living well for their last days. Boccaccio explains that none of these things worked, but he also notices that avoiding a sick person did help. More importantly, Boccaccio realizes that avoiding the possessions of a sick person was crucial in slowing the spread of the plague.
With our current knowledge of the germ theory, Boccaccio's observations seem obvious at best. However, it's important to remember that people in this time had no idea that disease was spread through microorganisms. I was impressed simply with their realization that the disease is contagious. Further, they implemented quarantine regulations and prevented sick people from entering their cities. This seems revolutionary, and it likely saved many lives. Since we also know that the specific pathogen involved in this plague is a bacterium, we know now that (unlike with viruses) the bacteria that spread this disease can live pretty much indefinitely on nonliving surfaces, relying on their hosts only for motility rather than for survival. If Boccaccio was able to notice the spread of this disease through surface contamination, it is likely that others noticed this as well. This begs the question: how did observations such as Boccaccio's contribute to the eventual rise of Pasteur's germ theory in the late 1800's?