Abstract
The first electric projecting microscope and the first published photomicrographs harnessed recent technological developments to provide improved methods of medical illustration for educational purposes. Both projects were the work of two Frenchmen. The impetus came from the microscopist Dr Alfred Donné (1801–78), discoverer of trichomonas vaginalis and leukaemia. Implementation was primarily by his medical‐student assistant, Léon Foucault (1819–68), who later gained fame as a physicist, especially with his pendulum demonstration of the Earth’s rotation.