Technologies

Arsenic-based medicine, Wm. R. Warner & Co., about 1900

Arsenic was widely used as a medicine in the 19th and 20th centuries. The development of forensic toxicology coincided with the spread of mass-produced and commercially distributed medicines and poisons (sometimes the same thing), and an associated rise in murders and suicides involving those substances.

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.