tugfoigel writes with this excerpt from the Boston Globe:
"For more than a century, carbon monoxide has been known as a deadly toxin. In an 1839 story, Edgar Allan Poe wrote of 'miraculous lustre of the eye' and 'nervous agitation' in what some believe are descriptions of carbon monoxide poisoning, and today, cigarette cartons warn of its health dangers. But a growing body of research, much of it by local scientists, is revealing a paradox: the gas often called a silent killer could also be a medical treatment. It seems like a radical contradiction, but animal studies show that in small, extremely controlled doses the gas has benefits in everything from infections to organ transplantation."