Hermann Emil Louis Fischer (; 9 October 1852 – 15 July 1919) was a German chemist and 1902 recipient of the Nobel Prize in Chemistry. He discovered the Fischer esterification. He also developed the Fischer projection, a symbolic way of drawing asymmetric carbon atoms. He also hypothesized lock and key mechanism of enzyme action. He never used his first given name, and was known throughout his life simply as Emil Fischer. Early years and career Fischer was born in Euskirchen, near Cologne, the son of Laurenz Fischer, a businessman, and his wife Julie Poensgen. After graduating he wished to study natural sciences, but his father compelled him to work in the family business until determining that his son was unsuitable. Fischer then attended the University of Bonn in 1871, but switched to the University of Strasbourg in 1872. He earned his doctorate in 1874 under Adolf von Baeyer with his study of phthaleins, and was appointed to a position at the university. In 1875 von Baeyer was asked to succeed Justus von Liebig at the University of Munich and Fischer went there with him to become an assistant in organic chemistry. In 1878 Fischer qualified as a "Privatdozent" at Munich, where he was appointed associate professor of analytical chemistry in 1879. In 1882 he was appointed professor of chemistry at the University of Erlangen and in 1885 at the University of Würzburg. In 1892 he succeeded von Hofmann as professor of chemistry at the University of Berlin. Fischer married Agnes Gerlach in 1888. She died seven years later, leaving him a widower with three sons. The younger two died during their military service in World War I, but the oldest, Hermann, became an organic chemist. He died in Berlin on July 15, 1919 at the age of 66. Research In 1875, the year following his engagement with von Baeyer, he published his discovery of the organic derivatives of a new compound of hydrogen and nitrogen, hydrazine. He investigated their derivatives, establishing their relation to the diazo compounds, and he noted the readiness with which they entered into combination with other substances, giving origin to a wealth of hitherto unknown compounds. Of such condensation products undoubtedly the most important are the hydrazones, which result from the interaction with aldehydes and ketones. His observations, published in 1886, that such hydrazones, by treatment with hydrochloric acid or zinc chloride, yielded derivatives of indole,