Planetary Microbes: Christian Gottfried Ehrenberg, the Agency, and the Politics of Microbes, 1840s–1850s

Christian Gottfried Ehrenberg (1795–1876) researched living and fossil microbes (infusoria) from air, sediment, or food samples. His discovery around 1840 that infusoria from the Berlin underground would damage buildings caused an early public microbe scare. In the context of the cholera epidemic of 1848, Ehrenberg devoted his attention to blood-red discoloration of food, which he identified as an innocuous red microbe. Both cases allow understanding the goal of this natural history of microbes: Following up on Alexander von Humboldt, he aimed at a full picture of microbes’ place in nature, such as for geological and biological processes, including humans. In a period of political instability, Ehrenberg’s investigations were more than an early chapter in the historiography of microbiology. His conservative-reformist perspective on materialism, religion, and the state sheds new light on the relationship of science and politics around 1848. Not least, Ehrenberg’s mid-nineteenth-century argument about the omnipresence and big impact of microscopic life resonates with contemporary debates about microbes’ planetary agency.