Leeuwenhoek

From Wikipedia:

Antonie Philips van Leeuwenhoek[1] (October 24, 1632August 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]

In 1648 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[citation needed]. 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. In 1669 he obtained a degree[citation needed] in geography, leading to his later appointment as geographer in 1679[citation needed].

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 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.[3] Such work firmly established his place in history as one of the first and 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.

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[4]. Such a method was also discovered independently by A.Mosolov and A.Belkin in the Novosibirsk State Medical Institute[5].

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.[6] 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:

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


 

(See Wikipedia for references)

One Comment to “Leeuwenhoek”

  1. Does anyone know where I could find a complete collection of Leeuwenhoek’s letters that are translated? I am doing this for History Day and I can’t find them anywhere!! They would be a great primary source! HELP! somebody please

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