He described symptoms of lead poisoning. Franklin observed that roofers, plumbers, and other artisans working with the pliant metal often experienced joint paint, stiffness, and paralysis, as well as severe intestinal problems. Friends reported that the same symptoms appeared in drinkers of rum distilled using coils made of pewter, which has a high lead content. As a contemporary epidemiologist might have, Franklin diagnosed lead poisoning: “It affects among tradesmen those that use lead, however different their trades, as glazers, type-founders, plumbers, potters, white-lead makers and painters.” He urged caution in handling the substance and equipping stills with tin coils. (DEA Picture Library, Granger, NYC)