I’m reading a really cool book right now, called Poisons of the Past, by Mary Kilhourne Matossian. It’s kind of a Freakonomics for medical historians. In her witch persecution chapter, she very meticulously lays out the argument that a fungus called ergot that infected rye (and, less often, wheat) may have caused much of the witch hysteria in early modern Europe.
When ingested in sufficient quantities, ergot causes a disease called “ergotism,” which can take one of two charming forms: gangrenous ergotism, where a vasoconstrictive chemical causes the victim to lose limbs, fingers, and toes to dry gangrene, or convulsive ergotism, which can cause nervous dysfunction, including writhing, tremors, delusions, and hallucinations. In the past they called it “fits.”
Ergot was more likely to form on rye when the preceding winter was cold, or when there was a wet, cloudy spring, which lengthened the time the flowers were opened and made the plant more vulnerable to infection.
Ergotism tended to affect children and teenagers more severely, so they were perceived as victims of bewitchment. The targets of witch-hunts tended to be the “healers” in a village, usually older women with knowledge of the medicinal properties of herbs. It was a high-risk profession; to restore health was seen as “white magic,” and to make someone ill was seen as “black magic.” So when people fell ill, the healers got blamed. Kind of a medieval malpractice suit.
What’s fascinating is that Matossian notes how witchcraft persecutions and ergotism fit a definite pattern. She has some really impressive yet incomprehensible (to me) math equations, involving multiple regression coefficients, that show the correlation between witch persecutions and temperatures and prices of rye. But the upshot of her argument is that the location of witch trials in western Europe between 1580 – 1650 was concentrated in places where rye was the staple cereal, and the highest concentrations occurred in these regions when the weather was both cold and wet, and therefore ideal for the production of ergot.
Top: Detail from Hexenflug der “Vaudoises” auf dem Besen, Miniatur in einer Handschrift von Martin Le France, Le champion des dames, 1451, via Wikimedia
Middle: An image of a witchand her familiar spirits taken from a publication that dealt with the witch trials of Elizabeth Stile, Mother Dutten, Mother Devell and Mother Margaret inWindsor, 1579.
Bottom: “Arresting a Witch,” Harper’s New Monthly Magazine, Vol. 67, (June – November), 1883: 221, via Wikimedia Commons