Welcome to The Mind of the Mad Hatter

The root of the term "mad hatter" is drawn from a time when mercury was used in the process of curing felt used in some hats. It was impossible for hatters to avoid inhaling the mercury fumes given off during the hat making process. Over time, the residual mercury caused neurological damage, as well as confused speech and distorted vision. As the mercury poisoning progressed to more dangerously high levels, sufferers could also experience psychotic symptoms, such as hallucinations. Given that anyone exhibiting an altered mental state was dubbed mad at the time, the cause of such malady, and subsequent death of such people doubtless went unexplained for a long time.