Rye grain is the most occurring source for the toxic ergot fungus. Could it be ergot poisoning that started the hysteria?

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Ergot: Nature's LSD

In February 1692, Elizabeth Parris, the daughter of the village's new minister, fell mysteriously ill. The 10-year-old girl began to exhibit strange behavior -- barking at her father, throwing herself about her room, and screaming of her skin being pinched and stung. After local physician William Griggs was confounded by the girl's symptoms and the failure of the treatments he tried on her, he pronounced that evil was at work on the girl. She was "possessed," and soon other girls in the village followed her into her illness.

Since Puritans believed the devil worked in league with witches, the already suspicious Salem residents began to look at one another. At the center was Tituba, a Barbadian slave who worked for the Reverend Samuel Parris, Elizabeth's father. Tituba and other residents found themselves accused by the girls who were suffering fits and convulsions.

No historian has concluded that it was indeed witchcraft that caused the girls' illness, and there are varying explanations for the supposed possessions. Perhaps most interesting is historian Linda Caporael's claim that it was ergot poisoning that originally created the hysteria.

Ergot is the result of a mold -- toxic and often fatal to humans -- which grows on grain. For centuries, farmers knew of the mold -- which they called cockspur -- but assumed it was harmless [source: Shelton]. Some people believed that the cockspur, which looks like black whole grains, was simply grain cooked by the sun [source: Caporael]. This was not the case, however.