The World Within

The beginning of Ingrid Rowland's article in the NYRB:

The invention of the microscope in the seventeenth century revealed a miniature world no less vast and complicated than the depths of the starry heavens, themselves gloriously unveiled not long before by the telescope. Creatures previously invisible to human eyes proved to be crafted in detail as marvelous as that of any visible plant or beast, a fact that threw religion and science (in those days still known as natural philosophy) into an existential confusion, from which neither discipline has yet emerged entirely. It was one thing to discover new continents or new constellations, and quite another to discover, as Antonie van Leeuwenhoekthe Dutch inventor of the microscopedid with some horror, that whole kingdoms of "animalcules" were carrying on their lives within his own mouth.

(Image by Flickr user nebarnix; hat tip: 3QD)