Matthias Jakob Schleiden (April 5, 1804 – June 23, 1881) was a German botanist, co-founder (with Theodor Schwann) of cell theory.
Matthias Jakob Schleiden was born in Hamburg on April 5, 1804. His father was the Hamburg municipal physician. Schleiden continued his legal studies, graduating in 1827. He then established a legal practice, but after a period of emotional depression and a suicide attempt, he changed professions.
He studied natural science at the University of Göttingen in Göttingen, Germany, but transferred to the University of Berlin in 1835 to study plants. Johann Horkel, Schleiden's uncle, encouraged him to study plant embryology. He soon developed his love of botany into a full-time pursuit. Schleiden preferred to study the structure of plants under a microscope. As professor of botany at the University of Jena, he wrote Contributions to our Knowledge of Phytogenesis (1838), in which he claimed that all plants are composed of cells. Thus, Schleiden and Schwann were the first to formulate what was then an informal belief as a principle of biology equal in importance to the atomic theory of chemistry. He also recognized the importance of the cell nucleus, discovered in 1831 by Scottish botanist Robert Brown, and realized its connection to cell division.
He became professor of botany at the University of Dorpat in 1863. He concluded that all parts of plants are made of cells and that an embryonic plant organism arises from a cell.
He died in Frankfurt am Main on 23 June 1881.
Schleiden was an early advocate of evolution. In a lecture on the "History of the Plant World" published in his book Die Pflanze und ihr Leben ("The Plant: A Biography") (1848) there is a passage that embraced the transmutation of species. He was one of the first German biologists to accept Charles Darwin's theory of evolution. He has been described as one of the leading proponents of Darwinism in Germany. With Die Pflanze und ihr Leben, reprinted six times in 1864, and his Studien: Populäre Vorträge ("Studies: Popular Lectures"), both written in a form accessible to lay readers , Schleiden contributed to creating an impetus to popularize science in Germany.
Beiträge zur Phytogenesis. In: Archiv für Anatomie, Physiologie und wissenschaftliche Medicin. 1838, S. 137–176. ("Contributions to Phytogenesis", "Archive of Anatomy, Physiology and Scientific Medicine, 1838)
Grundzüge der wissenschaftlichen Botanik nebst einer methodologischen Einleitung als Anleitung zum Studium der Pflanze. 2 Teile. Leipzig 1842 u. 1843, spätere Auflagen unter dem Titel Die Botanik als inductive Wissenschaft bearbeitet; Nachdruck: Olms, Hildesheim/Zürich/New York 1998 ("Fundamentals of Scientific Botany, Together with a Methodological Introduction as a Guide to the Study of Plants", in two parts, Leipzig 1842 and 1843, later editions were published under the title " Botany analyzed from the perspective of inductive science.")
Die Pflanze und ihr Leben. Engelmann, Leipzig 1848 ("The life of plants."
Das Alter des Menschengeschlechts, die Entstehung der Arten und die Stellung des Menschen in der Natur. Engelmann, Leipzig 1863. ("The age of the human race.", the origin of species and man's position in nature.")
Das Meer. edition and publication A. Sacco Nachf., Berlin 1867; Nachdruck: Severus, Hamburg 2012, ("The Sea")
Die Rose. Geschichte und Symbolik in ethnographischer und kulturhistorischer Beziehung. Verlag und Druck Wilhelm Engelmann, Leipzig 1873; Nachdruck: Sändig, Wiesbaden 1973, ("The Rose...History and symbolism in its ethnographic and cultural-historical relationship.")
Editors (1998). «Matthias Jakob Schleiden