Marcellin (or Marcelin) Pierre Eugène Berthelot (October 25, 1827 - March 18, 1907) was a French chemist and politician.
He was born at Paris, the son of a doctor. After doing well at school in history and philosophy, he turned to science. In 1851 he became a member of the staff of the Collège de France as assistant to A.J. Balard, his former master, and about the same time he began his life-long friendship with Ernest Renan. In 1854, he made his reputation by his doctoral thesis, Sur les combinaisons de la glycérine avec les acides, which described a series of beautiful researches in continuation and amplification of M.E. Chevreul's classic work. In 1859 he was appointed professor of organic chemistry at the École Supérieure de Pharmacie, and in 1865 he accepted the new chair of organic chemistry, which was specially created for his benefit at the Collège de France. He became a member of the Academy of Medicine in 1863, and ten years afterwards entered the Academy of Sciences, of which he became perpetual secretary in 1889 in succession to Louis Pasteur. He was appointed inspector general of higher education in 1876, and after his election as life senator in 1881 he continued to take an active interest in educational questions, especially as affected by compulsory military service. In René Goblet's ministry of 1886-1887 he was minister of public instruction, and in the Bourgeois cabinet of 1895-1896 he held the portfolio for foreign affairs. His scientific jubilee was celebrated in Paris in 1901. He died suddenly, immediately after the death of his wife Sophie Niaudet (1837-1907), at Paris, and was buried with her in the Panthéon. He had six children
His investigations on the synthesis of organic compounds were published in numerous papers and books, including Chimie organique fondée sur la synthèse (1860) and Les Carbures d'hydrogène (1901). Again he held that chemical phenomena are not governed by any peculiar laws special to themselves, but are explicable in terms of the general laws of mechanics that are in operation throughout the universe; and this view he developed, with the aid of thousands of experiments, in his Mécanique chimique (1878) and his Thermochimie (1897). This branch of study naturally conducted him to the investigation of explosives, and on the theoretical side led to the results published in his work Sur la force de la poudre et des matières explosives (1872), while on the practical side it enabled him to render important services to his country as president of the scientific defence committee during the siege of Paris in 1870-71 and subsequently as chief of the French explosives committee.
In later life he turned to the study of the earlier phases of the science which he did so much to advance, and students of chemical history are greatly indebted to him for his book on Les Origines de l'alchimie (1885) and his Introduction à l'étude de la chimie des anciens et du moyen âge (1889), as well as for publishing translations of various old Greek, Syriac and Arabic treatises on alchemy and chemistry (Collection des anciens alchimistes grecs, 1887-1888, and La Chimie au moyen âge, 1893). He was also the author of Science et philosophie (1886), which contains a well-known letter to Renan on "La Science idéale et la science positive," of La Révolution chimique, Lavoisier (1890), of Science et morale (1897), and of numerous articles in La Grande Encyclopédie, which he helped to establish.