Mad as a Hatter.

The article focuses on the origin of the phrase Mad Hatter, a diseases caused by mercury poisoning, in the U.S. The 19th century felt hat makers in Danbury, Connecticut were exposed to mercury nitrate as they isolated fur from the pelt. The hat makers, like the mad hatters in France and England, suffered mercury poisoning, which attacks the central nervous system. The poisoned workers displayed symptoms which include drooling, lurching gait, hair loss and hallucinations.