In La Vie et ses Problèmes (1939), French biologist Jean Rostand writes “They say a living being is always born of someone similar to him. But until the discovery of electrical magnetization, one could also have said that every magnet originated from a pre-existing magnet” (14). Since Thales of Miletus, the understanding of the elusive notion of “life” has been linked to magnetism. Rostand’s analogy partakes of this tradition but also alludes to a rupture. Following the discovery of electromagnetism during the first half of the nineteenth century, the generation of life could be conceived not only in terms of the reproduction of the same, exemplified by magnetic contagion, but also in terms of a relation based on the difference between two forces of nature–electricity and magnetism–distinguished by their own physical laws. Thus the advent of electromagnetism and its subsequent applications–most notably the dynamo–provided a new physical model for conceptualizing difference and repetition.