On the night of 1 September 1944, in the railroad town of Mattoon, Illinois, a woman reported that a sickly-sweet odour had drifted through her bedroom window — and that as it thickened, her legs and lower body went numb. Her daughter felt it too. The next day’s Mattoon Journal-Gazette ran the story under a headline that did half the epidemiology to come: “Anesthetic Prowler on Loose.”
Within days the prowler was everywhere. Residents reported the sweet gas at their screens by night — nausea, vomiting, dryness of the mouth, and above all that signature transient paralysis; some glimpsed a tall figure in dark clothes, by one account a woman dressed as a man; one householder found a cloth on her porch that reeked of chemicals. Over about two weeks, some two dozen households (counts vary with the counting) reported attacks. Mattoon armed itself: husbands sat porches with shotguns, vigilante car patrols swept the streets, the state police came in with crime labs, and the FBI hovered. The commissioner promised the gasser would be caught within days.
Nothing was ever caught. No chemical was identified — the cloth’s analysis came back useless; no two attacks yielded consistent physical evidence; victims examined at hospital showed no organic signs; and several “attacks” evaporated on inspection (one gas cloud traced to a spilled bottle of nail polish remover; odours matched to the town’s chemical plants riding the night wind). As police scepticism made the papers, the attacks — in the pattern that became famous — stopped as suddenly as they had begun. The final official verdict: mass hysteria, assisted by imagination and the Journal-Gazette.
The textbook case
A young psychologist, Donald Johnson, interviewed the principals and published in 1945 the study that made Mattoon immortal in the literature: the case fitted no crime and every marker of mass psychogenic illness — real symptoms, honestly experienced, propagating through suggestion along social and media networks, in a wartime town primed by years of poison-gas headlines and blackout prowler fears; victims were disproportionately those who had just read the coverage. Mattoon joined a lineage the site’s readers will recognise — from the dancing plagues to Tanganyika’s laughter and the West Bank’s fainting schools — and the local embarrassment was such that the town preferred silence for decades.
The stubborn footnote: later researchers (notably Scott Maruna, arguing for a real, disturbed local chemist) have insisted the first cluster of attacks reads more physically than the theory allows, and that “hysteria” conveniently spared the police an unsolved case. The mainstream verdict stands — but the Mad Gasser keeps his tenure in the footnotes, as phantom attackers do: never caught, never quite dismissed, and permanently useful as the measure of how a fright travels through a town at the speed of print.