Nicolas-Théodore de Saussure (14 October 1767 – 18 April 1845) was a Swiss chemist and student of plant physiology who made seminal advances in phytochemistry. He is one of the major pioneers in the study of photosynthesis. Biography Nicolas-Théodore de Saussure was born into a wealthy, aristocratic, Genevan family, many of whose members were accomplished in the natural sciences, including botany. He was the second child of Horace-Bénédict de Saussure (1740–1799), who was an eminent geologist, meteorologist, physicist and Alpine explorer, and Albertine-Amélie Boissier (1745–1817). His great uncle, Charles Bonnet, was a famous naturalist whose research included experiments on plant leaves. His grandfather Nicolas de Saussure was a noted agriculturist, for whom Nicolas-Théodore was named. Nicolas-Théodore was called "Théodore" to distinguish him from his grandfather, and he published his professional papers under the name Théodore de Saussure after his father died. (While his father was alive, Théodore's papers were published under the name "de Saussure fils", as was the custom of the day for the sons of scientists having the same surname. Nicolas-Théodore, his sister, Albertine, and brother, Alphonse, were educated at home because their father thought the educational system of the day was inferior. From 1782 to 1786, he attended the University of Geneva, where he studied math, science, and history. During the early years of the French Revolution he traveled abroad, meeting with eminent scientists in London. He traveled abroad again in the late 1790s, and in 1800 became acquainted with Parisian scientists and other luminaries. While there, he took courses in chemistry and presented a paper. Upon returning to Geneva in 1802, he accepted an honorary professorship of mineralogy and geology at the University of Geneva. Although he taught very little, he remained on the faculty until 1835. He lived quietly and somewhat reclusively, doing research in his own private laboratory (as was the custom for scientists of his day), but, like others in his family, he was active in public affairs in Geneva, and he served on the Genevan representative council. Nicolas-Théodore's sister, Albertine Necker de Saussure, was a noted early writer on the education of women. Nicolas-Théodore left no direct heirs, but he is the great uncle of Ferdinand de Saussure, an important linguist and semiotician. Career As a young man, Nicolas-Théodore accompanied his father on his Alpine expeditions, some of them under arduous conditions, and assisted him with experiments in physics, chemistry, mineralogy, and