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I pity the fool who don't know about ergot! Ergot is a fungus that grows on rye. It looks just like rye and it was harvested and made into bread in England and France. Ergot is also a potent hallucinogen and has been suspected for causing witch and werewolf trials in England and France. Such hysteria was virtually unheard around the Mediterranean where the climate was not suitable for ergot.
When the colonists came to America, they brought their ergot right along with them. Rye bread was primarily eaten by the poor (and illiterate) which may be account for why there are no records of anyone suspecting hallucination.
Interestingly, a kind of red tattoo-dye can also sometimes contain ergot. This was the plot of an episode of the X-files where they tried to boost ratings by having Scully get a red, hallinogenic tattoo on her ass. Man that show sucks.