The Devil in the rye
In the fields of Bavaria, a microscopic fungus may have contributed in one of history's darkest events. Claviceps purpurea is a parasitic fungus that infects rye and other cereals, particularly during cool, damp springs that follow cold winters. The fungus replaces a developing grain with a hard, dark, horn-like structure called a sclerotium, or ergot. When harvested and milled with the healthy grain, these ergots contaminate the flour and introduce potent chemicals into the food supply.
These chemicals are ergot alkaloids, complex molecules that have powerful effects on the human body. One of the most important is lysergic acid, the precursor from which chemist Albert Hofmann first synthesized LSD in 1938. Other alkaloids cause severe constriction of blood vessels. Ingesting contaminated bread can lead to a condition called ergotism, which historically presented in two horrifying forms: gangrenous and convulsive. Outbreaks often appeared in summers following wet springs, ideal conditions for the fungus to proliferate.
St. Anthony's Fire and demonic possession
Gangrenous ergotism, known as St. Anthony's Fire, caused an intense burning sensation in the limbs. The restricted blood flow led to dry gangrene, causing fingers, toes, and even entire limbs to blacken, mummify, and fall off. Convulsive ergotism attacked the central nervous system. Its symptoms included painful muscle spasms, seizures, and severe hallucinations, mania, or psychosis. Victims described seeing demons or feeling crawling sensations on their skin.
These symptoms align with some accounts from European witch trials. In nearby Bamberg, one of the largest witch trials in history raged from 1626 to 1632, leading to the execution of as many as 1,000 people. This period saw the Thirty Years' War, crop failures, and famine—conditions that created both social tension and an environment favorable to the ergot fungus. While direct proof is elusive and the theory is debated, the ergotism hypothesis, first proposed in detail by Linnda Caporael in 1976 for the Salem witch trials, explains the behaviors that were interpreted as demonic possession and witchcraft. The bizarre testimonies and physical contortions of the accused in trials like those in Bamberg may have been, in some cases, the tragic result of a fungus lurking in their daily bread.