Inheritor's Powder

This is the story of how an infamous murder case led to the birth of modern toxicology. In the 19th century criminal poisoning with arsenic was frighteningly easy. For a few pence and with few questions asked, it was possible to buy enough poison to kill off an entire family, hence arsenic's popular name: the Inheritor's Powder. Yet if poisoning was easy, it was a notoriously difficult crime to prove.