Dozens and dozens of mercury-laden purgative pills invented by Founding Father Benjamin Rush were an indispensible part of the Corps of Discovery's kit; the toxic-but-effective tablets helped explorers cope with a very-low-fiber diet. (Fort Clatsop, Clatsop County; 1805) (For text and pictures, see http://www.offbeatoregon.com/H1006d_BiliousPills.html)