Perhaps you've heard the expression, "Mad as a hatter." Well, that expression has its roots in reality. Fur trappers found plenty of beaver in Northern Michigan, and many of those pelts were turned into hats. Unfortunately, the milliners used arsenic and mercury to cure the hides as part of the hat-making process. These heavy metals could cause poisoning, with the poor milliner going mad as a result. This top hat made with beaver fur was produced somewhere from 1890-1920 by the Pease Bros. Company. A word of warning: be careful how you handle old taxidermy and furs. Those heavy metals can literally drive you crazy!