If it weren’t for Snow’s science, stubbornness, persistence, and passion for the truth, cholera might have raged on for another decade or more, taking thousands or even millions of lives. When I think about Snow and his accomplishment, what has always grabbed me most—and impressed me—is the way he insinuated himself into the epidemic. Nobody hired or paid him—or even asked him—to solve this epidemic. But he had a crucial tool at his disposal, epidemiology, and a problem right in front of him, in his own neighborhood, and that was enough for him to get started.
