Antoni van Leeuwenhoek’s discoveries, later sent to the Royal Society, sparked a rush to observe these microscopic “animalcules” (little animals); it turned out that what Leeuwenhoek had observed were protozoa; it was estimated that there were 8,280,000 of them in a single drop of water, more than the inhabitants of Leeuwenhoek’s home country, the Netherlands: the world was teeming with life in ways and numbers never before suspected.
