... is another name for ergotism, which is a disease caused by ingestion of the alkaloids produced by ergot, a fungus that infects rye and other cereals.
The symptoms of ergotism can be either convulsive (painful seizures and spasms, etc.) or gangrenous (the result of constriction of the blood vessels by the alkaloids).
The disease is known as St. Anthony's fire because in the Middle Ages, monks of the Order of St. Anthony were particularly successful in treating its gangrenous symptoms.
© Macclesfield Quiz League 2017