William Beaumont (1785–1853), an army surgeon, performed some of the earliest studies on digestion. In 1822, Alexis St. Martin was accidentally wounded by a shotgun blast. Beaumont began treatment of the wound immediately. St. Martin’s recuperation lasted nearly three years, and the enormous wound healed, except for a small opening leading into his stomach. A fold of flesh covered this opening; when this was pushed aside the interior of the stomach was exposed to view. Through the opening, Beaumont was able to extract and analyze gastric juice and stomach contents at various stages of digestion, observe changes in secretions, and note the stomach’s muscular movements. The results of his experiments and observations formed the basis of our modern knowledge of digestion.