In the late 1830s, in Berlin, the German scientist Robert Remak looked at frog embryos and chicken blood under a microscope. He was hoping to capture the birth of a cell, a particularly rare event in chicken blood, and so he waited. And waited. And then, late one evening, he saw it: under his scope, he watched a cell quiver, enlarge, bulge, and split in two, giving rise to “daughter” cells. Nothing less than a jolt of euphoria must have shot up Remak’s spine, for he had found incontrovertible evidence that developing cells arose from the division of preexisting cells—Omnis cellula e cellula,
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