"The toxicity of mercury is not a recent discovery either. Galen, who died about 200AD wrote about the toxicity of mercurials. As to the therapeutic uses of mercury compounds the “Chemical technology reference” makes this statement: “...in the 13th century, as a result of Arabian influence, such therapeutic uses of mercury were finally recognized by Western Europe. Some of these uses are specially supported by recorded history in Egypt 5000 years ago and, in China and India dating over 4000 years ago."