What is Christian Gottfried Ehrenberg?
{{Infobox scientist |name = Christian Gottfried Ehrenberg |image = Ehrenberg, Christian Gottfried, by Eduard Radke.jpg |image_size = 230px |caption = Christian Gottfried Ehrenberg |birth_date = 19 April 1795 |birth_place = [[Delitzsch]] |death_date = 27 June 1876 |death_place = [[Berlin]] |nationality = [[Germany|German]] |field = [[Natural history]] |prizes = Leeuwenhoek Medal (1877) }} '''Christian Gottfried Ehrenberg''' (19 April 1795 &ndash; 27 June 1876) was a [[Germany|German]] [[Natural history|naturalist]], [[zoologist]], [[Comparative anatomy|comparative anatomist]], [[geologist]], and [[microscope|microscopist]]. He was one of the most famous and productive [[scientist]]s of his time. == Microscopic organisms == Ehrenberg was appointed professor of [[medicine]] at Berlin University in 1827. In 1829 he accompanied [[Alexander von Humboldt]] through eastern [[Russia]] to the [[China|Chinese]] frontier. After his return he began to concentrate his studies on microscopic organisms, which then were not much studied. For nearly 30 years Ehrenberg examined samples of water, [[soil]], sediment, blowing dust and rock and described thousands of new [[species]], among them well-known [[flagellate]]s such as [[Euglena]], [[ciliate]]s such as ''[[Paramecium aurelia]]'' and ''Paramecium caudatum'', and many [[fossil]]s, in nearly 400 scientific publications. He was particularly interested in a unicellular group of [[protist]]s called [[diatom]]s, but he also studied, and named, many species of [[radiolaria]], [[foraminifera]] and [[dinoflagellates]]. These researches built up our [[knowledge]] of the [[microorganism]]s of certain [[geological formation]]s, especially of the [[chalk]], and of the marine and freshwater accumulations. Until Ehrenberg took up the study it was not known that considerable masses of [[Rock (geology)|rock]] were composed of minute forms of animals or plants. He also demonstrated that the [[p