BBC - History - Historic Figures: Antonie van Leeuwenhoek (1632 - 1723)

On August 26, 1723, Antonie van Leeuwenhoek, Dutch microscopist who was the first to observe bacteria and protozoa and naturalistic died at the age of 90. From the article:

"Van Leeuwenhoek was a Dutch textile merchant who became a pioneer of microbiology.

Antonie van Leeuwenhoek was born in Delft on 24 October 1632. In 1648, van Leeuwenhoek was apprenticed to a textile merchant, which is where he probably first encountered magnifying glasses, which were used in the textile trade to count thread densities for quality control purposes. Aged 20, he returned to Delft and set himself up as a linen-draper. He prospered and was appointed chamberlain to the sheriffs of Delft in 1660, and becoming a surveyor nine years later.

In 1668, van Leeuwenhoek paid his first and only visit to London, where he probably saw a copy of Robert Hooke's 'Micrographia' (1665) which included pictures of textiles that would have been of interest to him. In 1673, he reported his first observations - bee mouthparts and stings, a human louse and a fungus - to the Royal Society. He was elected a member of the society in 1680 and continued his association for the rest of his life by correspondence.

In 1676, van Leeuwenhoek observed water closely and was surprised to see tiny organisms - the first bacteria observed by man. His letter announcing this discovery caused widespread doubt at the Royal Society but Robert Hooke later repeated the experiment and was able to confirm his discoveries.

As well as being the father of microbiology, van Leeuwenhoek laid the foundations of plant anatomy and became an expert on animal reproduction. He discovered blood cells and microscopic nematodes, and studied the structure of wood and crystals. He also made over 500 microscopes to view specific objects.

He also discovered sperm, which he considered one of the most important discoveries of his career, and described the spermatozoa from molluscs, fish, amphibians, birds and mammals, coming to the novel conclusion that fertilisation occurred when the spermatozoa penetrated the egg."