Antonie van Leeuwenhoek

Antonie van Leeuwenhoek (October 24, 1632 - August 30, 1723) was an indefatigable scientist, inventor and tradesman from Delft, Netherlands who lived at the turn of the 17th and 18th centuries. He is commonly known as the "Father of Microbiology"; that title is well deserved, but diminishes his importance in other disciplines. His original thoughts and dedicated actions advanced so many fields that he is considered to be one of the greatest scientists of all time.^[1].

By refining the glass buttons that were then used by drapers to magnify their view of cloth, Leeuwenhoek created the first true (single lens) microscopes ^[2] and was the first person to observe and describe single-celled organisms (microorganisms) that he, not knowing any other language than Low Dutch, called kleijne dierkens (microscopic animals). In the English translation of his letters to the Royal Society these were called animalcules. ^[3]

He was also the first to record microscopic observations of muscle fibers, bacteria, spermatozoa and blood flow in capillaries (small blood vessels), and to advance techniques in the micro-dissection of tissues. This work helped lay the foundations of Medicine, Surgery, and Cell biology, besides Microbiology. With respect to the reproduction of mammals, he took issue with the epigenists who thought that all life is pre-existent in eggs. Having discovered spermatozoa in 1677, van Leeuwenhoek held the opposite "animalculist" point of view that that sperm cells (which he saw as animalcules) contain in miniature the future lifeform.

Van Leeuwenhoek's early discoveries in the field of microbiology can be likened to Galileo's early discoveries in the field of astronomy. Both men used the newly available optical technologies of their day to make major discoveries that entirely overturned traditional beliefs and theories in their respective fields, and both men were initially met with strong skepticism and resistance to the inevitable conclusions that their discoveries led to. Ultimately van Leeuwenhoek was more fortunate than Galileo in that his discoveries were widely accepted and applauded in his lifetime, whereas Galileo's were not appreciated until long after his death.

Van Leeuwenhoek was an indefatigable workman, who ground over 500 optical lenses. Nine of the more than 400 different microscopes he built still exist today. These microscopes are made of silver or copper metal frames holding his hand-ground lenses. Those nine that have survived the years are able to magnify up to 270 times, but on the basis of his drawings, van Leeuwenhoek is thought to have made some instruments that could magnify up to 500 times.

He was a remarkably creative abstract thinker who was interested in knowledge for its own sake. His curiosity was legendary, as was his openness to new ideas. Some of that latter quality might have been helped by his lack of any formal science training in his youth. He was never indoctrinated into the strict dogma of his day. Although he considered his technical improvements in optics to be quite proprietary, and closely guarded his inventions from others, he freely shared the findings that he made from them. In doing so, he "opened up the entire world of microscopic life to the scientific community".^[4]

Contents 1 Overview life and work 2 Recognition by the English Royal Society 3 Later discoveries 4 Revolutionizing the microscope and microscopy 5 Religious interpretations of van Leeuwenhoek's discoveries 6 Footnotes

[edit] Overview life and work

". . my work, which I've done for a long time, was not pursued in order to gain the praise I now enjoy, but chiefly from a craving after knowledge, which I notice resides in me more than in most other men. And therewithal, whenever I found out anything remarkable, I have thought it my duty to put down my discovery on paper, so that all ingenious people might be informed thereof." Antony van Leeuwenhoek. Letter of June 12, 1716 ^[5]

Antonie Leeuwenhoek was christened Thonis, but signed his name Antonij, which corresponds with 'Anthony' in modern English. The first name, "Antonie", by which he has become known, was invented by American scholars and is close to the spelling of his name as "Antoni" (see picture above). Van Leeuwenhoek's given name can also be found written as Anthon, Anthony, Antonie, Antony, Anthonie, Antoni, Antonio and Anthoni. The family called itself van ^[6] Leeuwenhoek ("lion's corner") because their house was on a corner (Dutch: hoek) next to the Leeuwenpoort (Lion's gate) in Delft; his full name was Thonis Philipszoon (son of Philip) van Leeuwenhoek (pronounced 'Laywenhook').

Born to the basket maker Philippus Thoniszoon van Leeuwenhoek and Margaretha Jacobsdochter Bel van den Bergh, he secured at age 16 an apprenticeship with a Scottish cloth merchant in Amsterdam. There, in 1648, he saw his first simple microscope (a microscope with a single lens), a tool used by textile merchants. This particular instrument was a magnifying glass mounted on a small stand and it enlarged by 3 times the cloth viewed through it (magnifying power of 3). He soon acquired one for himself. After doing well in the cloth trade, he moved back to Delft to start his own drapery business, which was a great financial success. In 1660, he was appointed chamberlain of the Lord Regents of Delft, a mark of distinction.

Van Leeuwenhoek probably knew about the book by Robert Hooke, titled Micrographia, published in 1665. That book is believed to have influenced him to use his microscopes to investigate the world beyond the fabrics that he sold.

In 1669 he obtained a degree in geography, and was appointed geographer in 1679. He made good use of the huge lead provided by his lens preparing methods. He studied a broad range of microscopic phenomena, and shared the resulting observations freely with groups such as the English Royal Society. Such work firmly established his place in history as one of the first and one of the most important explorers of the microscopic world. With regards to the construction of his microscopes, however, Leeuwenhoek maintained throughout his life that there were aspects of their construction "which I only keep for myself," including in particular his most critical secret of how he created lenses.

[edit] Recognition by the English Royal Society

After developing his method for creating powerful lenses and applying them to a thorough study of the microscopic world, Leeuwenhoek was introduced via correspondence to the English Royal Society by the famous Dutch Physician Regnier de Graaf. He soon began to send copies of his recorded microscopic observations to the Royal Society. In 1673 his earliest observations were published by the Royal Society in its journal: Philosophical Transactions. Amongst these published observations were Van Leeuwenhoek's accounts of bee mouthparts and stings... .

Van Leeuwenhoek's relationship with the Royal Society was soon severely strained. In 1676 his credibility was questioned when he sent the Royal Society an account of his first observations of single-celled organisms. Heretofore, the existence of such organisms was entirely unknown. Thus, even with his established reputation with the Royal Society as a reliable observer, his observations of microscopic life were initially met with skepticism. Eventually, in the face of Van Leeuwenhoek's insistence, the Royal Society arranged to send an English vicar, as well as a team of respected jurists and doctors to Delft, Holland to determine whether it was in fact Van Leeuwenhoek's ability to observe and reason clearly, or perhaps the Royal Society's theories of life itself that might require reform. Finally, Van Leeuwenhoek's observations were fully vindicated by the Society. Van Leeuwenhoek's vindication resulted in his appointment as a Fellow of the Royal Society in 1680. Over the 50 years that followed, he wrote approximately 560 letters to the Society and other scientific institutions, dealing with the subjects of his investigations.

In 1981 The British microscopist Brian J. Ford found that Leeuwenhoek's original specimens^[7] 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.

[edit] Later discoveries

Amongst Van Leeuwenhoek's many discoveries are: in 1674 he discovered infusoria (dated zoölogical category,) in 1676 he discovered bacteria, in 1677 he discovered spermatozoa and in 1682 he discovered the banded pattern of muscular fibers.

He died at the age of 90, on August 30, 1723 at Delft.

[edit] Revolutionizing the microscope and microscopy

Van Leeuwenhoek's interest in microscopes and a familiarity with glass processing led to one of the most significant, and simultaneously well-hidden, technical insights in the history of science. By placing the middle of a small rod of lime glass in a hot flame, van Leeuwenhoek could pull the hot section apart like taffy to create two long whiskers of glass. By then 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. An experienced businessman, van 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.

[edit] Religious interpretations of van Leeuwenhoek's discoveries

Van Leeuwenhoek was a Dutch Reformed Calvinist. He often referred with reverence to the wonders God designed in making creatures great and small. He believed that his amazing discoveries were further proof of the great wonder of God's creation.^[8][9]

Van Leeuwenhoek's discoveries helped to overturn the traditional belief of the time in the spontaneous generation of life that went back to Aristotle. This belief was generally held by the 17th century scientific community, and was tacitly endorsed by the 17th century Church. However, the Church's position on the nature of spontaneous generation was ambivalent.^[10] Possibly because van Leeuwenhoek's discoveries of microscopic life appeared to pose no direct challenge to any Church doctrines such as the doctrine of creationism, the Church made no effort to challenge any of van Leeuwenhoek's discoveries. It was only 200 years later when Charles Darwin incorporated van Leeuwenhoek's discoveries of microscopic life as a key element of his theory of evolution that it was recognized that van Leeuwenhoek's findings might lend support to any challenge to traditional Church doctrine on the origins of life.

[edit] Footnotes

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