Robert Hooke and Anton Van Leeuwenhoek discovered the existence of microscopic organisms between 1665 and 1683. The presentation of the micro fungus Mucor in Hooke’s Micrographia (1665) is the first published depiction of a microorganism. In 1674, Leeuwenhoek became the first person to see the tiny, single-celled protozoa that swim around in ponds and water butts.
The organisms discovered until then were comparatively larger than those like bacteria, which were even smaller than protozoa. In 1676, Leeuwenhoek made a lens that could magnify up to 280 times. Using this lens, he observed some of the larger types of bacteria collected from his mouth. Leeuwenhoek used certain techniques to watch them. These techniques probably involved lighting the microscopic organisms from a side, so that they would stand out like dust in a sunbeam.
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