The recent outbreak of Ebola in parts of Africa–and the frightened posts and live-tweets that accompanied two infected health workers as they returned to the US–give us a glimpse not only of an epidemic’s power but of our private terrors. Self-preservation, fear of the unknown, and a desire to protect the boundaries of nations, persons, bodies and cells brings out the best and worst in us. History provides both sides; the uninfected locked up with the infected in 14th century plague houses, left to starve and suffer in the dark–or doctors like Cleveland’s Horace Ackley, who personally combated and...