LEEUWENHOEK, or [[Leuwenhoek, Anthony Van]] (1632-1723), Dutch microscopist, was born at Delft on the 24th of October 1632.
The beginning of definite knowledge on the phenomenon of fermentation may be dated from the time of Antony Leeuwenhoek, who in 1680 designed a microscope sufficiently powerful to render yeast cells and bacteria visible; and a description of these organisms, accompanied by diagrams, was sent to the Royal Society of London.
The Old Church, founded in the 11th century, but in its present form dating from 1476, contains the monuments of two famous admirals of the 17th century, Martin van Tromp and Piet Hein, as well as the tomb of the naturalist Leeuwenhoek, born at Delft in 1632.
The accurate investigation of the lowest forms of animal life, commenced by Leeuwenhoek and Swammerdam, and continued by the remarkable labours of Reaumur, Abraham Trembley, Bonnet, and a host of other observers in the latter part of the 17th and the first half of the 18th centuries, drew the attention of biologists to the gradation in the complexity of organization which is presented by living beings, and culminated in the doctrine of the echelle des titres, so powerfully and clearly stated by Bonnet, and, before him, adumbrated by Locke and by Leibnitz.
Under the influence of the touchstone of strict inquiry set on foot by the Royal Society, the marvels of witchcraft, sympathetic powders and other relics of medieval superstition disappeared like a mist before the sun, whilst accurate observations and demonstrations of a host of new wonders accumulated, amongst which were numerous contributions to the anatomy of animals, and none perhaps more noteworthy than the observations, made by the aid of microscopes constructed by himself, of Leeuwenhoek, the Dutch naturalist (1683), some of whose instruments were presented by him to the society.