Van Leeuwenhoek, Antonie (1632-1723)

Dutch pioneer of microscopic research. He ground his own lenses, some of which magnified up to 300 times. With these he was able to see individual red blood cells, sperm, and bacteria, achievements not repeated for more than a century. Leeuwenhoek was born in Delft and apprenticed to a cloth merchant. From 1660, having obtained the sinecure of chamberlain to the sheriffs of Delft, he devoted much of his time to lens grinding and microscopy. From 1672 to 1723 he described and illustrated his observations in more than 350 letters to the Royal Society of London. His fame was such that he was visited by several reigning monarchs, including Frederick I of Prussia and Tsar Peter the Great. Leeuwenhoek ground more than 400 lenses, which he mounted in various ways in single-lens microscopes. Most of them were very small (some were about the size of a pinhead). In 1674 he discovered protozoa, which he called 'animalicules', and calculated their sizes. He also studied the structure of the lens in the eye, muscle striations, insects' mouthparts, the fine structure of plants, and discovered parthenogenesis in aphids.