IN THE BAD old days of life under sail - when the press gangs were rounding up innocent civilians, uniforms were nonexistent, and life below decks was malodorous, damp and wretchedly unhygienic - the Royal Navy tended, even in times of war, to lose far more men to disease than to enemy action. Yellow fever was a particular peril for sea dogs serving on the West Indies station, as the Scottish novelist Tobias Smollett discovered when, as a youthful ship's surgeon, he took part in the futile siege of Cartagena during the War of Jenkins's Ear; but equally dreaded, and by no means restricted to tropical climes, was scurvy, the most infamous of naval ailments. The early symptoms included bleeding gums, cuts and bruises that failed to heal, a 'proneness to swoon', and an unwholesome smell about the person; more often than not, on long voyages in particular, these led on to blindness, hallucinations and death. Burying the afflicted up to the neck in sand, dosing with spiced sulphuric acid, and phlebotomy or blood- letting, that universal eighteenth-century panacea, were recommended as possible cures for what was widely regarded as a venereal disease; but all to no avail.

While Smollett, furious and frustrated, was watching British sailors and soldiers dropping like flies under the tropical sun, Commodore George Anson was leading an expedition to capture the great Spanish treasure fleet off the coast of Peru. His pursuit of Spanish gold led on to a four-year circumnavigation of the