Ergot

Ergot is a fungus that replaces the grain of rye with a hard dark body packed with alkaloids, and for most of its recorded history its relationship with religion has been through catastrophe rather than ceremony.

Eating bread made from infected rye produces ergotism, which takes two broad forms. The gangrenous form constricts the blood supply to the extremities, producing a burning pain followed by blackening and the loss of fingers, feet and limbs. The convulsive form produces spasms, contortions and hallucinations. Outbreaks swept medieval Europe repeatedly, and because the affliction was epidemic, agonising and inexplicable, it was understood as a divine visitation.

It was named Saint Anthony's fire, and the Order of Saint Anthony was founded in the eleventh century to care for sufferers, becoming one of the earliest specialised hospital orders in Europe. Its houses kept the amputated limbs on display. Recovery was attributed to the saint, and pilgrimage to his relics was a treatment, which had an effect that nobody understood at the time: pilgrims ate bread made elsewhere, from uncontaminated grain, and improved on the journey.

The cause was not identified until the seventeenth century and the mechanism much later. The alkaloids were eventually isolated and turned into medicine, and one derivative, lysergic acid, became the starting point for a wholly different chapter.

The Antonite order that commissioned this altarpiece did not run a general hospital. Its monks specialised in treating ergotism, a poisoning caused by a fungus that grows on rye and other grains and, when eaten in contaminated bread, produces burning limb pain, gangrene, seizures and hallucinations. Medieval sufferers called it Saint Anthony's Fire, after the desert saint the Antonites had adopted as their patron, and the monastery at Isenheim, fifteen miles from Colmar, was built specifically to house and treat its victims.

Guy Guers, the monastery's preceptor for over two decades, commissioned Grunewald and Hagenauer to furnish the hospital chapel with an altarpiece patients would actually see from their beds, and the imagery answers that brief directly rather than staying generic. Grunewald's Christ on the cross is not serenely idealised; his skin is mottled and greenish, his fingers curl in visible spasm, and several art historians have argued the discolouration deliberately echoes the gangrenous tissue damage ergotism itself produced, so that a dying patient looking at the crucified Christ saw a body marked the way their own body was marked.

That reading turns the altarpiece from simple decoration into something closer to visual medicine: a devotional image built to tell a suffering patient that their pain was shared rather than isolating, and that the Resurrection panel waiting behind the Crucifixion, radiant and whole, was the promised outcome of exactly that suffering. Few surviving altarpieces anywhere were built this specifically for the illness of the people who would pray in front of them.

Ergot appears twice in arguments that are cited far more confidently than the evidence supports.

The first is Eleusis. For nearly two thousand years the Mysteries at Eleusis initiated Greeks in a rite whose central experience was never disclosed, and initiates drank a barley preparation called the kykeon. In 1978 Wasson, Hofmann and Ruck proposed that the kykeon was psychoactive and that the agent was ergot growing on the barley, water-extracted to separate the soluble alkaloids from the toxic ones. The attraction of the theory is that it explains why an experience so consistently described as overwhelming could be produced on schedule for thousands of people. The objections are serious: no ancient source describes anything of the kind, the required separation is delicate, and the argument runs backwards from the effect to a cause that would explain it. It is a hypothesis and the atlas records it as one.

The second is Salem. Linnda Caporael proposed in 1976, and Mary Matossian developed at length, that the 1692 accusations followed convulsive ergotism in the local rye. Historians of Salem have largely rejected it. The symptom pattern does not fit well, the afflicted were concentrated in ways an infected food supply would not produce, and the documentary record supports explanations grounded in the community's own conflicts.

Both claims share a shape worth noticing: a physical cause offered for a religious phenomenon, appealing precisely because it is tidy.