Antonie van Leeuwenhoek

 

   

Antonie van Leeuwenhoek
Portrait of Antonie van Leeuwenhoek (1632–1723) by Jan Verkolje
Born	(1632-10-24)October 24, 1632 Delft, Dutch Republic
Died	August 26, 1723(1723-08-26) (aged 90) Delft, Dutch Republic
Residence	Netherlands
Nationality	Dutch
Fields	Microscopist and Biologist
Signature

Antonie Philips van Leeuwenhoek^{[note 1]} (/ˈleɪvənhʊk/, Dutch: [ɑnˈtoːni vɑn ˈleːuə(n)ˌɦuk] ( listen); October 24, 1632 – August 26, 1723) was a Dutch tradesman and scientist. He is commonly known as "the Father of Microbiology", and considered to be the first microbiologist. He is best known for his work on the improvement of the microscope and for his contributions towards the establishment of microbiology.
Raised in Delft, Netherlands, Leeuwenhoek worked as a draper in his youth, and founded his own shop in 1654. He made a name for himself in municipal politics, and eventually developed an interest in lensmaking. Using his handcrafted microscopes, 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 (small blood vessels). Leeuwenhoek did not author any books; his discoveries came to light through correspondence with the Royal Society, which published his letters.

Contents

 [hide] 

• 1 Early life and career
• 2 Microscopic study
  • 2.1 Recognition by the Royal Society
  • 2.2 Scientific fame
• 3 Techniques and discoveries
• 4 Death and legacy
• 5 See also
• 6 Notes
• 7 References
• 8 Sources
• 9 External links

Early life and career

Sir William Davidson of Curriehill had appointed Leeuwenhoek in 1648 as his assistant. Leeuwenhoek left after six years.^[2][3] (By Abraham van den Tempel, 1664)

Antonie van Leeuwenhoek was born in Delft, Dutch Republic, on October 24, 1632. Christened Thonis, he is believed to be of Dutch ancestry: his father, Philips Antonysz van Leeuwenhoek, was a basket maker who died when Antony was five years old. His mother, Margaretha (Bel van den Berch), came from a well-to-do brewer's family, and married Jacbon Jansz Molijn, a painter, after Philips' death. Antony had four older sisters, Margriete, Geertruyt, Neeltge, and Catharina.^[4] Little is known of his early life; he attended school near Leyden for a short time before being sent to live in Benthuizen with his uncle, an attorney and town clerk. He became an apprentice at a linen-draper's shop in Amsterdam at the age of 16.^[5]
He married Barbara de Mey in July 1654, with whom he would have one surviving daughter, Maria (four other children died in infancy). That year he returned to Delft, where he would live and study for the rest of his life. He opened a draper's shop, which he ran throughout the 1650s. Barbara died in 1666, and in 1671 Leeuwenhoek married Cornelia Swalmius, with whom he had no surviving children.^[6] His status in Delft grew throughout the following years, although he would remain an obscure figure outside of the city. He received a lucrative municipal title as chamberlain for the Delft sheriffs' assembly chamber in 1660, a position which he would hold for almost 40 years. In 1669 he was named a surveyor by the Court of Holland; later he would become a municipal "wine-gauger" in charge of the city's wine imports.^[7]

The Geographer by Johannes Vermeer.

Leeuwenhoek was a contemporary of another famous Delft citizen, painter Johannes Vermeer, who was baptized just four days earlier. It has been suggested that he is the man portrayed in two of Vermeer's paintings of the late 1660s, The Astronomer and The Geographer. However, others argue that there appears to be little physical similarity. Because they were both relatively important men in a city with only 24,000 inhabitants, it is likely that they were at least acquaintances. Also, it is known that Leeuwenhoek acted as the executor of the will when the painter died in 1675.^{[8][note 2]}

Microscopic study

While running his draper's shop, Leeuwenhoek began to develop an interest in lensmaking, although few records exist of his early activity. 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 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.

Microscopic section through one-year-old ash tree (Fraxinus) wood, drawing made by Leeuwenhoek.

Recognition by the Royal Society

After developing his method for creating powerful lenses and applying them to study of the microscopic world, Leeuwenhoek introduced his work to his friend, the prominent Dutch physician Reinier de Graaf. When the Royal Society in London published the groundbreaking work of an Italian lensmaker in their journal Philosophical Transactions of the Royal Society, de Graaf wrote to the journal's editor Henry Oldenburg with a ringing endorsement of Leeuwenhoek's microscopes which, he claimed, "far surpass those which we have hitherto seen". In response the Society published in 1673 a letter from Leeuwenhoek, which included his microscopic observations on mold, bees, and lice.^[9]

Letter of 1677 from Leeuwenhoek to Oldenburg, with the latter's English translation behind. The full correspondence remains in the Royal Society Library.

Leeuwenhoek's work fully captured the attention of the Royal Society, and he began regularly corresponding with the Society regarding his observations. He had at first been reluctant to publicize his findings, regarding himself as a businessman with little scientific, artistic, or writing background, but de Graaf urged him to be more confident in his work.^[10] By his death in 1723, he had written 190 letters to the Society, detailing his findings in a wide variety of fields, centered around his work in microscopy. He only wrote letters, in his own colloquial flavor of Dutch; he never published a proper scientific paper. He had strongly preferred to work alone, distrusting the sincerity of those who offered their assistance.^[11] The letters were translated into Latin or English by the German Oldenburg, who learnt Dutch in order to be able to do so.
Despite the initial success of Leeuwenhoek's relationship with the Royal Society, this relationship was soon severely strained. In 1676, his credibility was questioned when he sent the Royal Society a copy of his first observations of microscopic single-celled organisms. Previously, the existence of single-celled 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 both skepticism and open ridicule.^[12] Eventually, in the face of Leeuwenhoek's insistence, the Royal Society arranged for Alexander Petrie, minister to the English Reformed Church in Delft, Benedict Haan, at that time Lutheran minister at Delft, and Henrik Cordes, then Lutheran minister at the Hague, accompanied by Sir Robert Gordon and four others to determine whether it was in fact Leeuwenhoek's ability to observe and reason clearly, or perhaps the Royal Society's theories of life itself that might require reform. Finally in 1677^[13] Leeuwenhoek's observations were fully vindicated by the Society.^[14]
He was elected to the Royal Society in February 1680 on the nomination of William Croone, a then-prominent physician.^{[note 3]} Leeuwenhoek was "taken aback" at the nomination, which he considered a high honor, although he did not attend the induction ceremony in London, nor did he ever attend a Royal Society meeting.^[16]

Scientific fame

By the end of the 17th century, Leeuwenhoek had a virtual 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.^[17] He was visited over the years by many notable individuals, such as Russian Tsar Peter the Great. 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.^[18] An experienced businessman, 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.
He was visited by Leibniz, William III of Orange and his wife, the Amsterdam burgemeester (the mayor) Johan Huydecoper, the latter very interested in collecting and growing plants for the Hortus Botanicus Amsterdam and all gazed at the tiny creatures. Nicolaes Witsen sent him a map of Tartaria and a mineral found near the origin of the river Amur.^[19] In 1698 Leeuwenhoek was invited in the boat of tsar Peter the Great. On the occasion Leeuwenhoek presented the tsar an "eel-viewer", so Peter could study the blood circulation, whenever he wanted.

Techniques and discoveries

Leeuwenhoek's microscopes by Henry Baker

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.^[20]
The microscopes were relatively small devices, the biggest being about 5 cm long.^[21] They are used by placing the lens very close in front of the eye, while looking in direction of the sun. The other side of the microscope had a pin, where the sample was attached in order to stay close to the lens. There were also three screws that allowed to move the pin, and the sample, along three axes: one axis to change the focus, and the two other axes to navigate through the sample.
Leeuwenhoek maintained throughout his life that there are aspects of microscope construction "which I only keep for myself", in particular his most critical secret of how he created lenses. For many years no-one was able to reconstruct Leeuwenhoek's design techniques. However, in 1957 C.L. Stong used thin glass thread fusing instead of polishing, and successfully created some working samples of a Leeuwenhoek design microscope.^[22] Such a method was also discovered independently by A. Mosolov and A. Belkin at the Russian Novosibirsk State Medical Institute.^[23]

Replica of microscope by Leeuwenhoek

Leeuwenhoek used samples and measurements to estimate numbers of microorganisms in units of water.^[24][25] He also made good use of the huge lead provided by his method. He studied a broad range of microscopic phenomena, and shared the resulting observations freely with groups such as the English Royal Society.^[26] Such work firmly established his place in history as one of the first and most important explorers of the microscopic world. He was one of the first people to discover cells, along with Robert Hooke.
Leeuwenhoek's main discoveries are:

• the infusoria (protists in modern zoological classification), in 1674
• the bacteria, (e.g., large Selenomonads from the human mouth), in 1676
• the vacuole of the cell.
• the spermatozoa in 1677.
• the banded pattern of muscular fibers, in 1682.^{[note 4]}

In 1687 he reported his research on the coffee bean. He roasted the bean, cut it into slices and saw a spongeous interior. The bean was pressed, and an oil appeared. He boiled the coffee with rain water twice, set it aside.^[27]
Like Robert Boyle and Nicolaas Hartsoeker, Leeuwenhoek was interested in the dried cochineal, trying to find out if the dye came from a berry or an insect.^[28][29][30]
Leeuwenhoek was a Dutch Reformed Calvinist.^[31] He often referred with reverence to the wonders God designed in making creatures great and small. He believed that his amazing discoveries were merely further proof of the great wonder of God's creation.^[32][33] Leeuwenhoek's discovery that smaller organisms procreate similarly to larger organisms challenged the contemporary belief, generally held by the 17th-century scientific community, that such organisms generated spontaneously. The position of the Church on the exact nature of the spontaneous generation of smaller organisms was ambivalent.^{[citation needed]}

Death and legacy

Antonie van Leeuwenhoek is buried in the Oude kerk in Delft

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.^[34] 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.^[35] 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.

See also

• Scientific revolution

Notes

1. Jump up ^ The spelling of Leeuwenhoek's name is exceptionally variant. He was christened as Thonis, but always went by Antonj (corresponding with the English Antony). The final j of his given name is the Dutch long i. Until 1683 he consistently used the spelling Antonj Leeuwenhoeck (ending in –eck) when signing his letters. Throughout the mid-1680s he experimented with the spelling of his name, and after 1685 settled on the most recognized spelling van Leeuwenhoek.^[1]
2. Jump up ^ In A Short History of Nearly Everything (p. 236) Bill Bryson alludes to rumors that Vermeer's mastery of light and perspective came from use of a camera obscura produced by Leeuwenhoek. This is one of the examples of the controversial Hockney–Falco thesis, which claims that some of the Old Masters used optical aids to produce their masterpieces.
3. Jump up ^ He was also nominated as a "corresponding member" of the French Academy of Sciences in 1699, but there is no evidence that the nomination was accepted nor that he was ever aware of it.^[15]
4. Jump up ^ A disease in the city of Kampen, Netherlands (1736), which originated (caused) by "little animals". These 'bloedloze dieren' (bloodless animals, the Invertebrata) are — most likely — the little animals described in the work of Antonie van Leeuwenhoek (Evert Valk, a physician about an epidemic in the city of Kampen during the year 1736)