Antonie van Leeuwenhoek

Antonie van Leeuwenhoek
Born	Antonie van Leeuwenhoek October 24, 1632(1632-10-24) Delft, Netherlands
Died	August 30, 1723 (aged 90) Delft, Netherlands
Residence	Delft, Netherlands
Nationality	Dutch
Occupation	Scientist, tradesman

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

Antonie Philips van Leeuwenhoek^[1] (October 24, 1632 – August 30, 1723) was a Dutch tradesman and scientist from Delft, the Netherlands. He is commonly known as "the Father of Microbiology", and considered to be the first microbiologist. He was born the son of a basket maker. At age 16, he secured an apprenticeship with a Scottish cloth merchant in Amsterdam. He is best known for his work on the improvement of the microscope and for his contributions towards the establishment of microbiology. Using his handcrafted microscopes he was the first to observe and describe single celled organisms, which he originally referred to as animalcules, and which we now refer 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).

During his lifetime Van Leeuwenhoek ground over 500 optical lenses. He also created over 400 different types of microscopes, only nine of which still exist today. His microscopes were made of silver or copper metal frames holding hand-ground lenses. Those that have survived the years are able to magnify up to 275 times. It is suspected, though, that Van 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.^[2]

Early involvement with the microscope

In 1653 in Amsterdam Van Leeuwenhoek saw his first simple microscope, a magnifying glass mounted on a small stand used by textile merchants capable of magnifying to a power of 3. He soon acquired one for his own use. In 1654, he left Amsterdam, moved back to Delft and started his own lucrative drapery business there. In 1660, he was appointed chamberlain of the Lord Regents of Delft. It is believed that soon after 1665 he read a book by Robert Hooke, titled Micrographia. His reading of Hooke's book is believed to have roused an interest in Van Leeuwenhoek to use his microscopes for the purpose of investigating the natural world beyond the mere quality of the fabrics he sold.^[3] In 1669 he obtained a degree in geography, leading to his later appointment as geographer in 1679 .

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, 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, 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.

Leeuwenhoek used samples and measurements to estimate numbers of micro-organisms in units of water.^[4][5] Leeuwenhoek 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.^[6] Such work firmly established his place in history as one of the first and most important explorers of the microscopic world.

Lenses secret

With skills, 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.

For a long time nobody could reconstruct Leeuwenhoek's know-how. But in the 1950s, D.L. Stong used thin glass thread fusing instead of polishing, and successfully created some working samples of a Leeuwenhoek design microscope^[7]. Such a method was also discovered independently by A.Mosolov and A.Belkin in the Novosibirsk State Medical Institute^[8].

Eventual recognition by the English Royal Society and later discoveries

Drawing of Van Leeuwenhoek's microscopes by Henry Baker, 1756

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.

Despite the initial success of Van 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. Heretofore, 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 certain 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 in 1680, 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 that year. After his appointment to the Society, he wrote approximately 560 letters to the Society and other scientific institutions over a period of 50 years. These letters dealt with the subjects he had investigated.

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.^[9] 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.

Amongst Van Leeuwenhoek's many discoveries are:

• in 1674 he discovered infusoria (protists in modern zoological classification)
• in 1676 he discovered bacteria, (e.g. large Selenomonads from the human mouth)
• in 1677 he discovered spermatozoa
• in 1682 he discovered the banded pattern of muscular fibers.^[10]

He died at the age of 90, on August 26, 1723 at Delft.

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 merely further proof of the great wonder of God's creation.^[11][12]

Van Leeuwenhoek's discoveries did eventually overturn the traditional belief of the time in the spontaneous generation of life. This belief was generally held by the 17th century scientific community, and was also tacitly endorsed by the 17th century Church. Still, the Church's position on the exact nature of spontaneous generation was ambivalent.^[13] Possibly because Van Leeuwenhoek's discoveries of microscopic life appeared at the time to pose no direct challenge to any Church doctrines such as the doctrine of creationism, the Church made no effort to challenge or question any of Van Leeuwenhoek's discoveries in any way.

Possible Vermeer connection

Van 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 Van Leeuwenhoek acted as the executor when the painter died in 1675. ^[14]

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 Van Leeuwenhoek.

See also

• Scientific Revolution

Footnotes

External links

• Dutch online biography of Van Leeuwenhoek
• Vermeer connection website
• University of California, Berkeley article on Van Leeuwenhoek
• Works by Antoni van Leeuwenhoek at Project Gutenberg
• Retrospective paper on the Leeuwenhoek research by Brian J. Ford.