Arsenic: The Inheritance Powder

Until the early nineteenth century few tools existed to detect a toxic substance in a corpse. Sometimes investigators deduced poison from the violent sickness that preceded death, or built a case by feeding animals a victim's last meal, but more often than not poisoners walked free. As a result murder by poison flourished. It became so common in eliminating perceived difficulties, such as a wealthy parent who stayed alive too long, that the French nicknamed the metallic element arsenic poudre de succession, the inheritance powder.

Deborah Blum, The Poisoner's Handbook, 2010