IN EARLY SPRING 1721, a maritime fleet from Barbados arrived in Boston, Mass, and brought with it the beginnings of a smallpox epidemic. By autumn the disease had spread throughout the city and reached the neighboring towns of Cambridge, Charlestown, and Roxbury. The epidemic was especially hard on the young and elderly populations, with mortality rates ranging from 15% to 50%. Cotton Mather (1663-1728), a celebrated local clergyman, had read of a method employed in Turkey to prevent smallpox through inoculating healthy individuals by abrading their skin with a sharp instrument that had been dipped into material taken from a pock of a patient with active smallpox. The idea was to produce a mild form of smallpox from which the patient would recover and, as a result, be protected against a more severe attack. Mather attempted to interest several medical practitioners in Boston in this new procedure, but most ridiculed the idea, equating it with murder.