"Ridiculous statements"

What Dobell wrote about Leeuwenhoek in 1932 is still true today.

Outside of Holland little has been written about him which is not almost comically inaccurate. The biographical dictionaries are stuffed with ridiculous statements, and most historians of biology have hitherto been content to misprint their mistakes. Leeuwenhoek himself is, indeed, now almost unknown — notwithstanding his celebrity. "Little Aminals", p. 11.

“Ridiculous statements” are caused by:

•    Human error
•    No first-hand archival research / reliance on faulty secondary and tertiary research
•    Presentism
•    Agenda / propaganda
•    Disregard for history and historical fact
•    Confirmation bias
•    Inferences based on bad or insufficient evidence
•    Translation problems, both linguistic and cultural
•    The use of plausible but false statements in the service of a good story


A ubiquitous ridiculous statement tells us that Leeuwenhoek called the little animals that he discovered “animalcules”. If biologists today know only one thing about Leeuwenhoek, it is “animalcules”, usually spoken with a little grin. So quaint, those historical characters!

The word animalcule is a diminutive of animal, referring to small animals, from insects to mice, but usually invertebrates. It was first used in English in 1599 and it fell out of use after the mid-1880's. It is not a Dutch word, and its use in English gives an erroneous impression of Leeuwenhoek. He was a clear-eyed observer of things that had no name because no one had ever seen them before. Rather than try to give them some fancy name, he described them in simple, obvious terms that his readers could understand. Most often, Leeuwenhoek used dierken; frequently, he used diertgens or diertjes. Dier is animal and the -ken, -gen, or -je endings are common forms of diminutive in Dutch, then and now. Leeuwenhoek sometimes put kleine (small) or zere kleine (exceedingly small) in front of the noun.

Oldenburg translated the early letters, and he was the one who first translated dierkens as animalcules. Leeuwenhoek wasn't fluent in English, but he got all the numbers of Philosophical Transactions, so he knew what Oldenburg was doing. He borrowed other words from English, French, and Latin, such as ____ and ______. Yet he continued to use dierkens. A better translation is "little animals", which is what Dobell used in the title of his biography. Remember that Oldenburg was first and foremost a promoter of the new ideas, in this case, trying to make things seem more important and more what we would now call "scientific". Leeuwenhoek had his pretentious moments, but he was a committed empiricist. All he knew for sure was what he saw. They moved on their own, thus they were alive. They were not plants; thus, they were animals. They were unbelievably small. Thus: diertgens, little animals.

The Vermeer connection

Another repeated wrong statement is that Leeuwenhoek and the painter Johannes Vermeer knew each other well, that Leeuwenhoek introduced Vermeer to the camera obscura, and that Leeuwenhoek sat for a couple of Vermeer’s paintings. There is, in fact, no document to support any of those statements.

How many microscopes and letters?

The number of microscopes Leeuwenhoek made, the number of letters that he wrote, to whom he addressed them, and the number of letters he wrote to the Royal Society and were published in Philosophical Transactions have continually confounded authors. For example, “From the age of 40 he communicated his observations in more than 350 letters to the Royal Society of London”, Journal of Neurology, Neurosurgery, and Psychiatry, 1992;55:251. See the 2011 publication below, which upped it to 560 letters over the 50 years after 1680. [give ex for number of lenses and for number of articles]

While noting that videos about Leeuwenhoek have ridiculous statements of their own as well as improbably and historically inaccurate images, what follows is a sampling of other statements in print, in chronological order:


De la Crosse wrote erroneously that Leeuwenhoek’s “parents designed him for a chyrurgeon, which profession he has exercised some time with Honor.”


In A Catalogue raisonne of the Works of the most eminent Dutch Painters of the Seventeenth Century, translated by E. G. Hawke., C. H. de de Groot calls Leeuwenhoek a "physicist and surgeon of Haarlem".


Microbe Hunters: The Classic Book on the Major Discoveries of the Microscopic World by Paul de Kruif, is full of direct quotations that Leeuwenhoek never spoke and details that are not quite right in order to make the story flow. De Kruif wrote, “There is no doubt that … he was appointed janitor of the city hall of Delft”.


An illustration (right) by French art deco illustrator Pierre Brissaud shows Leeuwenhoek demonstrating microscopes as large as paddles to Catherine, wife of King Charles II of England, in 1711. There is no evidence of such a visit and in any case, she died in 1705.


The article "Leeuwenhoek, the Man: A Son of His Nation and His Time" by Maria Rooseboom published in the Bulletin of the British Society for the History of Science, vol. 1, no. 4 (Oct., 1950), pp. 79-85, got several little details wrong. She stated that Leeuwenhoek was born on November 4, 1632, which was his baptism date. She wrote that he was five when his mother remarried (he was eight) and that his apprenticeship in Amsterdam lasted 8 years, not the six years from 1648 to 1654. “In the same year, he married and opened a draper’s and haberdasher’s shop.” In fact, he opened his shop the following year.


An illustration (right) on the cover of a children's book, De lenzenslijper van Delft by A.D. Hildebrand shows Leeuwenhoek peering through a lens large enough for a telescope. The other microsocpes were double-lens microscopes that were never used by him.


World’s Greatest Creation Scientists, by David F. Coppedge, has a bogus quotation from Leeuwenhoek: “It would indeed be a miracle to get these animalcules by chance.” However, the quotation fits the author’s political agenda.


“Like being mauled by a swarm of gnats” by Scott Ostler in the San Francisco Chronicle, October 23, 2002, “It looks like what Anton van Leeuwenhoek, the inventor of the microscope, described when he looked at his first slide -- "Cavorting beasties."


A passage in Europe, 1450 to 1789: Encyclopedia of the Early Modern World, discusses what happened when people visited Leeuwenhoek:

When Leeuwenhoek had mastered a particular specimen, he would set up a permanent stand in his house, with a microscope devoted to that specimen, so that a visitor could go from station to station and observe swamp water, blood, insect parts, and other exotica without wasting time. … This required a great number of microscopes.

The source for this fantasy is not cited, but may well be Maria Rooseboom’s chapter in Measuring the Invisible World (1960). Note the qualifying phrases “must have been shown … would usually have been … might find.”

Those who were admitted to the sanctuary must have been shown many different kinds of research material. There would usually have been some small live fish for the demonstration of the capillary circulation, collections of gall insects or larvae of fleas, plárit-lice, and his sealed glass tubes containing oyster embryos. Here, too, they might find jars of crystallizing salts, while infusions of pepper, cloves, and nutmeg would be side by side with samples of rain-water and ditch-water. Finally, carefully put away in tin boxes, there were his numerous small microscopes, some of which he had made especially for studying a particular specimen, together with his razor with which he could cut the thinnest of plant sections.


In “The Strange Little Animals of Antony van Leeuwenhoek” by Luis H. Toledo-Pereyra, MD, PhD in the Journal of Investigative Surgery vol. 22, 2009 - Issue 1

… their children did not survive to adulthood. In 1671, he remarried and a child was born from this matrimony. … a job at the Delft sheriff’s office … a janitor for 39 years.


In “Water flea: vital to our survival”, in the San Francisco Chronicle, February 13, 2011, David Perlman wrote: "The water flea … has been known since 1669 when a Dutch scientist first examined it under Anton van Leeuwenhoek's primitive microscope."


The Deskarati blog <https://deskarati.com/2011/07/11/antonie-van-leeuwenhoek/> repeats an oft-told tall tale about Leeuwenhoek. The story has it that the Royal Society sent representatives to Delft

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, 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.


In Eye of the Beholder: Johannes Vermeer, Antoni van Leeuwenhoek, and the Reinvention of Seeing, Laura Snyder presents a cinematic ‘Ah-ha’ moment on page one of chapter one when Leeuwenhoek first discovers microbes in his study on the ground floor. "In the small Dutch city of Delft, Anthoni Leeuwenhoek … sits by the large window in his study. … If any of his neighbors happen to glance into the ground floor room as they pass by ...." His workspace was, in fact, on the floor above. See "The tensions between facts and fantasy" in Sources below for other erroneous statements in that book due to lack of adequate research in the primary sources.


Much of Deskarati’s tall tale was repeated word for word in Anatomy: An Encyclopedic Reference to the Language of Anatomy and Neuroanatomy. It Provides the Fascinating Origin of Terms and Biographies of Anatomists/Physicians Who Originated Them, by Ronald Bergman and Adel Afifi, physicians at the University of Iowa College of Medicine.

In the face of Leeuwenhoek's insistence, the Royal Society arranged for Alexander Petrie, minister to the English Reformed Church in Delft, Benedict Haan, Lutheran minister at Delft, Henrik Cordes minister at the Hague, accompanied by Sir Robert Gordon and several others to determine Leeuwenhoek's ability to observe and reason clearly, or whether the Royal Society's theories of life should be reformed.

This tall tale did not originate with the Wikipedia https://en.wikipedia.org/wiki/Antonie_van_Leeuwenhoek, of course, but it was recounted there, making it hard to tell whether the professors used Deskarati as a source or they both used the Wikipedia.

Eventually, in the face of van 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 van Leeuwenhoek's ability to observe and reason clearly, or perhaps, the Royal Society's theories of life that might require reform.

Following up on Leeuwenhoek’s ability to observe and reason clearly, Bergman and Afifi suggest that he may have been drunk. Their entry on Leeuwenhoek has a completely bogus and on the face of it unbelievable letter to Leeuwenhoek “full of ridicule and skepticism” from Henry Oldenburg referring to the letter first describing the little animals in October 1676.

Dear Mr. Anthony van Leeuwenhoek, your letter of October 10th has been received here with amusement. Your account of myriad "little animals" you see swimming in rain water, with the aid of your so-called "microscope," caused the members of the society considerable merriment when read at our most recent meeting. Your novel descriptions of the sundry anatomies and occupations of these creatures led one member to imagine that your "rainwater" might have an ample portion of distilled spirits -- imbibed by the investigator. Another member raised a glass of clear water and exclaimed, "Behold, the Africk of Leeuwenhoek." For myself, I withhold judgment as to the sobriety of your observations and veracity of your instrument. However, a vote having been taken among members (accompanied, I regret to inform you, by considerable giggling) it has been decided not to publish your communication in the Proceedings of this esteemed society. However, all here wish your "little animals" health, prodigality and good husbandry by their ingenious "discoverer."