Marcellin Pierre Eugène Berthelot:
Marcellin Berthelot was a French chemist.
Claim to Fame:
Berthelot was a French chemist who believed all chemical reactions depended on the action of physical forces that could be measured. He was also partly responsible for the end of the vitalism theory of organic chemistry. It was generally believed that organic compounds could only be formed from other organic sources and required some 'vital spark'. He synthesized hydrocarbons, natural fats and sugars from inorganic sources to disprove this theory.
He was responsible for the Thomsen-Berthelot principle in thermochemistry that postulated chemical changes produce heat and will produce the change that generates the most heat. This theory would be modified later by Helmholtz to consider not just heat, but the reaction's free energy.