Arsenic seems to have been the easiest poison for a would-be murderer to use–at least until the scientific work of Alexander Gettler and Charles Norris in the 1920s in New York that took the anonymity out of poisoning. I am planning to use arsenic to kill someone in an upcoming mystery, and so I need to learn all about it. Interesting facts: arsenic was nicknamed “inheritance powder” for its common use as a way to speed up one’s inheritance. That’s the story I’m going to tell, in a nutshell.
White arsenic seems to be the easiest poison to administer. Stirred into soup, coffee, or an alcoholic beverage, it is almost undetectable. (I plan to use coffee.) People who survived arsenic poisoning almost never reported tasting anything odd about their food or beverages. One scientist who studied arsenic use concluded that, of 820 arsenic deaths between 1752 and 1889, half were homicides. Others were suicides and accidents. In France in the 1800s, arsenic poisonings accounted for an estimated 40% of all murders. So it was common and undetectable . . . meaning the poisoner could almost certainly avoid discovery.
Symptoms include headaches, confusion, diarrhea, and drowsiness. But so many illnesses share those symptoms! Vomiting, cramping, stomach pain, and convulsions come next, but those symptoms could also be diagnosed as food poisoning, gastritis, or gastroenteritis. Arsenic wouldn’t normally spring to mind unless you knew your nephew was eager to inherit your fortune. And then, as in the famous case of George Wythe (Thomas Jefferson’s and John Marshall’s law professor), who was poisoned by his nephew for the inheritance, it is too late.
Mary Miley's Roaring Twenties 