Although he was actually a draper, the Dutchman Antonie van Leeuwenhoek (1632-1723) ground glass lenses and used them to examine the world about him. In the 1670s he made his first crude microscope with a tiny lens, and this allowed him to be the first person to see microscopic life such as bacteria, yeast and living blood cells. During his career, van Leeuwenhoek ground a total of 419 lenses, and his microscopes became progressively more effective.
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