Arsenic and its Discontents
Despite its poisonous nature, arsenic was very easy to get a hold on in the 19th century. It could be found in many household products. Swedish chemist Carl Wilhelm Scheele mixed copper, arsenic, hydrogen, and oxygen to produce a brilliant green pigment. These pigments were used in everything from children’s toys to soap, wallpaper, fabric, and even sweets! The fabric of a lady’s green ball gown might contain 100 grains of arsenic–and it takes only 4.5 grains to kill an adult!  Just as problematic were accidental uses. In 1858, 20 people died in Bradford, England, when a sweet-maker mistakenly bought white arsenic instead of sugar substitute for lozenges. 
Easy to obtain, cheap to purchase, and invisible when mixed with food, the fine white powder was very attractive to would-be poisoners. Two sensational trials brought the threat to national and international attention; the Bodle Case in England and the LaFarge case in France.
Trial and Error
In 1836, James Marsh would develop a test that could determine if arsenic was present. He had been called in to the Bodle Case, where a whole family became ill from tainted coffee (though only the elderly George Bodle died). His grandson John Bodle was brought to trial for murder, but Marsh was unable to convince the jury and set about inventing a new and better test. He constructed a simple glass apparatus capable of detecting minute traces of arsenic and measuring its quantity. Adding a sample of tissue or body fluid to a glass vessel with zinc and acid would produce arsine gas, which would oxidize when ignited, producing a silver-black metallic glaze. Young Bodle went free, though he later confessed to the crime . The Marsh test was not in vain, however…
Marie LaFarge’s husband had taken ill while on a business trip. Upon his return, Marie attended to his every need, scarecely leaving his side. A friend of the family noted peculiarly behavior, however. She was putting something in the food! When her husband Charles expired, she was brought up on charges for murder.The trial dragged on and on, dividing the French public. Was she to blame?
The illness began abroad, and Marie had an alibi (though as it turns out, she had sent a small cake to her husband while he was away.) The public was divided about her guilt and once again the Marsh test was brought in to ascertain the truth. As before, the test was in conclusive, but the prosecution did not rest. They decided it was time to bring in a true specialist, a man that would forever change the methodology of forensic science. His name was Mathieu Joseph Bonaventure Orfila… and our next blog post in this series will talk more about his methods.The Dittrick will be hosting an exhibit this spring that details more about forensics, the history and the artifacts of a science on the cutting edge of medicine and murder!
 Sandra Hempel. The Inheritor’s Powder: A Tale of Arsenic Murder and the New Forensic Science. New York: Norton, 2013.
 Ben Johnson. Dying for a Humbug, the Bradford Sweets Poisoning 1858. HistoricUK
 Marie Belloc Lowndes. Great French Mysteries: The Strange Case of Marie Lafarge. McClure’s Magazine v38, 1912.