Technologies

Arsenic-trioxide tablets, Wm. R. Warner & Co., about 1900

Arsenic trioxide, a toxic substance employed in goldmining and other industrial processes, was also used as a medicine in the 19th and 20th centuries (it is still used today to treat leukemia and other diseases). Bottles that featured raised ridges, skulls and crossbones, and the embossed word "poison" were designed so that people could distinguish poisons from other medicines, even in the dark.

National Museum of American History, Behring Center, Smithsonian Institution

The Marsh test

In 1832 police arrested John Bodle for lacing his grandfather's coffee with poison. Chemist James Marsh tested the drink in his laboratory, and confirmed the presence of arsenic by producing a yellow precipitate of arsenic sulfide. But the precipitate was unstable and, by the time of trial, had deteriorated. Without forensic proof, Bodle was acquitted. Stung by the verdict, Marsh devised a test that could better stand up in court. His 1836 "Marsh Test" won worldwide acclaim and became a standard procedure. But in subsequent decades Marsh's test was shown to be problematic, and in turn underwent a series of improvements.