Friedrich Wöhler. Image provided by Edgar Fahs Smith Memorial Collection, Department of Special Collections, University of Pennsylvania Library.		Organic synthesis In 1828 Friedrich Wöhler (1800–1882) synthesized urea completely from inorganic materials. This well-publicized creation of an organic compound from nonliving materials helped bring down the vital hypothesis, which held that a "life force" was necessary to create the diverse compounds found in living things. In more recent times synthesis of natural products has helped make expensive plant drugs more widely available. In the 1930s Percy Lavon Julian (1899–1975) and Josef Pikl synthesized the glaucoma drug physostigmine, making it inexpensive and widely available. Robert Burns Woodward (1917–1979) synthesized many natural products, among them chlorophyll in 1960 and vitamin B12 in 1971, expanding the capabilities of organic chemistry to create specific desired molecular structures.