Historically the idea is much earlier, it comes from the legends around Mithridates, King of Pontus, circa 100 BC: https://en.wikipedia.org/wiki/Mithridates_VI

Historically the idea is much earlier, it comes from the legends around Mithridates, King of Pontus, circa 100 BC: https://en.wikipedia.org/wiki/Mithridates_VI_of_Pontus#Mithridates.27_antidote https://en.wikipedia.org/wiki/Mithridates_VI_of_Pontus#Mithr... https://en.wikipedia.org/wiki/Mithridate https://en.wikipedia.org/wiki/Mithridate http://www.thefreedictionary.com/mithridatism http://www.thefreedictionary.com/mithridatism