Mercury poisoning: A probable cause of Isaac Newton's physical and mental ills

Abstract

The personal crisis of 1693 in die life of Sir Isaac Newton has frequently been discussed by scholars interested in the history and the psychology of genius. In 1693 Newton suffered from insomnia and poor digestion; and he also wrote irrational letters to friends. Although most scholars have attributed Newton’s breakdown to psychological factors, it is possible that mercury poisoning may have been the principal cause. Newtonian scholar Richard S. Westfall has studied the defence Newton made of his first publication, the theory of the composition of white light (which Newton himself considered ‘the oddest if not the most considerable detection which has hitherto been made in operations of Nature’).