Hat History: Mad as a Hatter
Posted by Veronica Hodur on March 01, 2017
Many people are familiar with the saying "Mad as a Hatter" and most are also aware that this comes from the side effects that hatter's experienced during the production of hats. But some may not know why this happened or what the side effects were.
The "hatter shakes" was a symptom of mercury poisoning through high exposure during the felting process. A mixture of mercury and other chemicals was used as a smoothing agent on animal pelts that would create fumes heavy with mercury that the hatter would then breathe in because of their small workspaces and poor ventilation.
The process of using mercury in felting began in France in the 17th century with a religious group called the Huguenots when the side effects of mercury poisoning were already known. It was kept a trade secret, with the risk of hat-making becoming increasingly dangerous, until the end of the century when the process was brought over to England and then slowly spread throughout Europe and the United States. The dangerous process was outlawed in 1898 in France but the process was used in America until as late as 1941. Even then the only reason the process ceased was because of the need of mercury for detonators in WWII.
The symptoms usually began with a small tremor in the hands which spread to the face and then would eventually develop into uncontrollable shaking. There were also side effects such as confusion, mental disturbance, irritability and "shyness."
Despite the name Mad Hatter in Lewis Carroll's novel Alice in Wonderland, the author admits that the character is not based on a hatter effected by mercury poisoning, but rather an eccentric furniture dealer named Theophilus Carter, who by all historical records did not suffer from poisoning of any kind.