German botanist and master microscopist who was influenced by Schelling's Naturphilosophie and the writings of Oken. He worked under Johannes Müller and studied primarily cells in plants. He observed that all plants seemed to be composed of cells, and is thus considered the co-founder of cell theory together with Schwann, with whom he consulted. Schleiden wanted to make cell formation analogous to crystal formation, and published his results in Beiträge zur Phytogenesis (Contributions of Phytogenesis, 1838). Schleiden was a vitalist, and thought the cell was the center of the vital force vitalism theory.

Oken, Schelling, Schwann