Antonie van Leeuwenhoek

Antonie Van Leeuwenhoek (October 24, 1632 – August 26, 1723) was a Dutch scientist. He was born in Delft, Dutch Republic, on October 24, 1632. He is also known as "the Father of Microbiology".  He is known for his work on the improvement of the microscope and for his contributions towards the establishment of microbiology. He was the first to observe and describe single-celled organisms, which he originally referred to as animalcules, and which are now referred to as microorganisms. He was also the first to record microscopic observations of muscle fibers, bacteria, spermatozoa, and blood flow in capillaries. Leeuwenhoek discoveries came to light through correspondence with the Royal Society, which published his letters.

Leeuwenhoek’s interest in microscopes and a familiarity with glass processing led to one of the most significant insights in the history of science. By placing the middle of a small rod of soda lime glass in a hot flame, Leeuwenhoek could pull the hot section apart to create two long whiskers of glass. Then, by reinserting the end of one whisker into the flame, he could create a very small, high-quality glass sphere. These spheres became the lenses of his microscopes, with the smallest spheres providing the highest magnifications.

 By the end of the 17th century, Leeuwenhoek had a monopoly on microscopic study and discovery. His contemporary Robert Hooke, an early microscope pioneer, bemoaned that the field had come to rest entirely on one man's shoulders. To the disappointment of his guests, Leeuwenhoek refused to reveal the cutting-edge microscopes he relied on for his discoveries, instead showing visitors a collection of average-quality lenses. Leeuwenhoek realized that if his simple method for creating the critically important lens was revealed, the scientific community of his time would likely disregard or even forget his role in microscopy. He therefore allowed others to believe that he was laboriously spending most of his nights and free time grinding increasingly tiny lenses to use in microscopes, even though this belief conflicted both with his construction of hundreds of microscopes and his habit of building a new microscope whenever he chanced upon an interesting specimen that he wanted to preserve. He made about 200 microscopes with different magnification.

 Leeuwenhoek made more than 500 optical lenses. He also created at least 25 microscopes, of differing types, of which only nine survived. His microscopes were made of silver or copper frames, holding hand-made lenses. Those that have survived are capable of magnification up to 275 times. It is suspected that Leeuwenhoek possessed some microscopes that could magnify up to 500 times. Although he has been widely regarded as a dilettante or amateur, his scientific research was of remarkably high quality.

Leeuwenhoek used samples and measurements to estimate numbers of microorganisms in units of water. He studied a broad range of microscopic phenomena, and shared the resulting observations freely with groups such as the English Royal Society.

In 1673, Leeuwenhoek began writing letters to the newly-formed Royal Society of London, describing what he had seen with his microscopes -- his first letter contained some observations on the stings of bees. For the next fifty years he corresponded with the Royal Society; his letters, written in Dutch, were translated into English or Latin and printed in the Philosophical Transactions of the Royal Society, and often reprinted separately.

 Such work firmly established his place in history as one of the first and most important explorers of the    

microscopic world.

Leeuwenhoek's main discoveries are:

1) The infusoria (protists in modern zoological classification), in 1674

2) The bacteria, (e.g., large Selenomonads from the human mouth), in 1676

3) The vacuole of the cell.

4) The spermatozoa in 1677.

5) The banded pattern of muscular fibers, in 1682.

By the end of his life, Leeuwenhoek had written approximately 560 letters to the Society and other scientific institutions concerning his observations and discoveries. Even when dying, Leeuwenhoek kept sending letters full of observations to London. The last few also contained a precise description of his own illness. He suffered from a rare disease, an uncontrolled movement of the midriff, which is now named Van Leeuwenhoek's disease. He died at the age of 90, on August 26, 1723 and was buried four days later in the Oude Kerk (Delft).

In 1981 the British microscopist Brian J. Ford found that Leeuwenhoek's original specimens had survived in the collections of the Royal Society of London. They were found to be of high quality, and were all well preserved. Ford carried out observations with a range of microscopes, adding to our knowledge of Leeuwenhoek's work.

References: www.google.com/wikipedia
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Prachi Shewale