Haunted HousesThis seems like an appropriate day to mention this, since I just discussed Fatal Fame in the previous post. I was listening to an episode of This American Life while I swam on Tuesday (I'm back to 2006 now), and as part of a Halloween episode, they mentioned that many of the "manifestations" of supernatural phenomena that occur inside houses are almost identical to the symptoms of carbon monoxide poisoning. They also mentioned multiple reportings of "haunted houses" that, when checked, showed very high levels of carbon monoxide, and when the ventilation systems were fixed, the manifestations went away.
The person they were discussing this with also strongly believes that's why reports of haunted houses have gradually decreased over time. He said that particularly in the gaslight era, carbon monoxide levels inside houses were often at dangerous levels.
Here's an excerpt from a Wikipedia entry on haunted houses:
Symptoms of carbon monoxide poisoning include listlessness, depression, dementia, emotional disturbances, and hallucinations. Many of the phenomena generally associated with haunted houses, including strange visions and sounds, feelings of dread, illness, and the sudden, apparently inexplicable death of all the occupants, can be attributed to carbon monoxide poisoning.
I also found a website with a story published in the American Journal of Ophthalmology in 1921. In it, a doctor describes a patient who lived in a house that was, by any measure, extravagantly haunted--over half a dozen people living in the house described terrifying (and repeated) incidents.
The furnace, as it turns out, was pouring fumes into the house instead of out through the chimney, and once it was repaired, the haunting stopped. The story is here, and it's a very good read, because the account is so vivid.