Antony van Leeuwenhoek (1632-1723)

Posted: October 24, 2016 by tallbloke in Education, History, innovation


. . . 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

Antony van Leeuwenhoek was an unlikely scientist. A tradesman of Delft, Holland, he came from a family of tradesmen, had no fortune, received no higher education or university degrees, and knew no languages other than his native Dutch. This would have been enough to exclude him from the scientific community of his time completely. Yet with skill, diligence, an endless curiosity, and an open mind free of the scientific dogma of his day, Leeuwenhoek succeeded in making some of the most important discoveries in the history of biology. It was he who discovered bacteria, free-living and parasitic microscopic protists, sperm cells, blood cells, microscopic nematodes and rotifers, and much more. His researches, which were widely circulated, opened up an entire world of microscopic life to the awareness of scientists.

Leeuwenhoek was born in Delft on October 24, 1632. (His last name, incidentally, often is quite troublesome to non-Dutch speakers: “layu-wen-hook” is a passable English approximation.) His father was a basket-maker, while his mother’s family were brewers. Antony was educated as a child in a school in the town of Warmond, then lived with his uncle at Benthuizen; in 1648 he was apprenticed in a linen-draper’s shop. Around 1654 he returned to Delft, where he spent the rest of his life. He set himself up in business as a draper (a fabric merchant); he is also known to have worked as a surveyor, a wine assayer, and as a minor city official. In 1676 he served as the trustee of the estate of the deceased and bankrupt Jan Vermeer, the famous painter, who had had been born in the same year as Leeuwenhoek and is thought to have been a friend of his. And at some time before 1668, Antony van Leeuwenhoek learned to grind lenses, made simple microscopes, and began observing with them. He seems to have been inspired to take up microscopy by having seen a copy of Robert Hooke‘s illustrated book Micrographia, which depicted Hooke’s own observations with the microscope and was very popular.
leeuwmicrosmLeeuwenhoek is known to have made over 500 “microscopes,” of which fewer than ten have survived to the present day. In basic design, probably all of Leeuwenhoek’s instruments — certainly all the ones that are known — were simply powerful magnifying glasses, not compound microscopes of the type used today. A drawing of one of Leeuwenhoek’s “microscopes” is shown at the left. Compared to modern microscopes, it is an extremely simple device, using only one lens, mounted in a tiny hole in the brass plate that makes up the body of the instrument. The specimen was mounted on the sharp point that sticks up in front of the lens, and its position and focus could be adjusted by turning the two screws. The entire instrument was only 3-4 inches long, and had to be held up close to the eye; it required good lighting and great patience to use.

Compound microscopes (that is, microscopes using more than one lens) had been invented around 1595, nearly forty years before Leeuwenhoek was born. Several of Leeuwenhoek’s predecessors and contemporaries, notably Robert Hooke in England and Jan Swammerdam in the Netherlands, had built compound microscopes and were making important discoveries with them. These were much more similar to the microscopes in use today. Thus, although Leeuwenhoek is sometimes called “the inventor of the microscope,” he was no such thing.

However, because of various technical difficulties in building them, early compound microscopes were not practical for magnifying objects more than about twenty or thirty times natural size. Leeuwenhoek’s skill at grinding lenses, together with his naturally acute eyesight and great care in adjusting the lighting where he worked, enabled him to build microscopes that magnified over 200 times, with clearer and brighter images than any of his colleagues could achieve. What further distinguished him was his curiosity to observe almost anything that could be placed under his lenses, and his care in describing what he saw. Although he himself could not draw well, he hired an illustrator to prepare drawings of the things he saw, to accompany his written descriptions. Most of his descriptions of microorganisms are instantly recognizable.

In 1673, Leeuwenhoek began writing letters to the newly-formed Royal Society of London, describing what he had seen with his microscopes — his first letter contained some observations on the stings of bees. For the next fifty years he corresponded with the Royal Society; his letters, written in Dutch, were translated into English or Latin and printed in the Philosophical Transactions of the Royal Society, and often reprinted separately. To give some of the flavor of his discoveries, we present extracts from his observations, together with modern pictures of the organisms that Leeuwenhoek saw.


Letter on the Protozoa – Published by the Royal Society

spirogyratinyIn a letter of September 7, 1674, Leeuwenhoek described observations on lake water, including an excellent description of the green charophyte alga Spirogyra: “Passing just lately over this lake, . . . and examining this water next day, I found floating therein divers earthy particles, and some green streaks, spirally wound serpent-wise, and orderly arranged, after the manner of the copper or tin worms, which distillers use to cool their liquors as they distil over. The whole circumference of each of these streaks was about the thickness of a hair of one’s head. . . all consisted of very small green globules joined together: and there were very many small green globules as well.”
vorticellatinyA letter dated December 25, 1702, gives descriptions of many protists, including this ciliate, Vorticella: “In structure these little animals were fashioned like a bell, and at the round opening they made such a stir, that the particles in the water thereabout were set in motion thereby. . . And though I must have seen quite 20 of these little animals on their long tails alongside one another very gently moving, with outstretched bodies and straightened-out tails; yet in an instant, as it were, they pulled their bodies and their tails together, and no sooner had they contracted their bodies and tails, than they began to stick their tails out again very leisurely, and stayed thus some time continuing their gentle motion: which sight I found mightily diverting.”

On September 17, 1683, Leeuwenhoek wrote to the Royal Society about his observations on the plaque between his own teeth, “a little white matter, which is as thick as if ’twere batter.” He repeated these observations on two ladies (probably his own wife and daughter), and on two old men who had never cleaned their teeth in their lives. Looking at these samples with his microscope, Leeuwenhoek reported how in his own mouth: “I then most always saw, with great wonder, that in the said matter there were many very little living animalcules, very prettily a-moving. The biggest sort. . . had a very strong and swift motion, and shot through the water (or spittle) like a pike does through the water. The second sort. . . oft-times spun round like a top. . . and these were far more in number.” In the mouth of one of the old men, Leeuwenhoek found “an unbelievably great company of living animalcules, a-swimming more nimbly than any I had ever seen up to this time. The biggest sort. . . bent their body into curves in going forwards. . . Moreover, the other animalcules were in such enormous numbers, that all the water. . . seemed to be alive.” These were among the first observations on living bacteria ever recorded.

Leeuwenhoek looked at animal and plant tissues, at mineral crystals and at fossils. He was the first to see microscopic foraminifera, which he described as “little cockles. . . no bigger than a coarse sand-grain.” He discovered blood cells, and was the first to see living sperm cells of animals. He discovered microscopic animals such as nematodes and rotifers. The list of his discoveries goes on and on. Leeuwenhoek soon became famous as his letters were published and translated. In 1680 he was elected a full member of the Royal Society, joining Robert Hooke, Henry Oldenburg, Robert Boyle, Christopher Wren, and other scientific luminaries of his day — although he never attended a meeting. In 1698 he demonstrated circulation in the capillaries of an eel to Tsar Peter the Great of Russia, and he continued to receive visitors curious to see the strange things he was describing. He continued his observations until the last days of his life. After his death on August 30, 1723, the pastor of the New Church at Delft wrote to the Royal Society:

. . . Antony van Leeuwenhoek considered that what is true in natural philosophy can be most fruitfully investigated by the experimental method, supported by the evidence of the senses; for which reason, by diligence and tireless labour he made with his own hand certain most excellent lenses, with the aid of which he discovered many secrets of Nature, now famous throughout the whole philosophical World.

British scientist Brian J. Ford has rediscovered some of Leeuwenhoek’s original specimens in the archives of the Royal Society of London. His study of these historic specimens and other material, using Leeuwenhoek’s own microscopes and other single-lens microscopes, has shown how remarkably good a scientist and craftsman Leeuwenhoek really was. Here’s the full story of Dr. Ford’s research.

Berkeley, California resident Al Shinn manufactures replicas of Leeuwenhoek microscopes. He has also made plans and instructions available, for those who would like to make their own Leeuwenhoek-type microscopes.

  1. Annie says:

    Thank you Tallbloke. Quite fascinating. He was a real scientist wasn’t he?

  2. Zeke says:

    In every great discipline, if you research it hard enough, and with some luck and pluck, you will find these men like Leeuwenhoek who were not a part of the educated class but who made many innovations, contributions, and discoveries. I find it “mightily diverting” that he was in fact a merchant.

    What the discoverers were doing is making observations and performing tests designed to determine real causes and effects. This simple empirical method was simply not practiced in Europe because of the extreme reverence and deference paid to two Greeks, Aristotle and Ptolemy. The writings of the Greeks formed the basis for Roman Church dogma in science, and the scholastic tradition.

    Any one who ever discovered anything had to overthrow some doctrine of Aristotle or Ptolemy, put it that way.

    Leeuwenhoek himself remarks on this in his own writings, and from his words you can discern the impatience he felt towards the fixed ideas of Aristotle and the learned class:


  3. Zeke says:

    “One of these minute Flies I placed before a microscope of much less magnifying power than that from which the wing was drawn; by this we see it to have two pretty horns on its head, each composed of many joints, and every joint covered with hairs. And in contemplating the horns, I took notice of the eyes, wherein I plainly perceived many obpical organs of which each eye consisted, as we observe in larger Flies. All these objects are represented at fig 24…

    In contemplating such minute animals as this, and considering that no part of them is made in vain, but that every one has its use, we see still further reason to admire the perfection of so minute a creature. And when we see the stupendous wisdom of Nature’s operations in the greatest, and in the least of her productions, we may well cry out again and again, ‘Away with the blind croakings of those followers of Aristotle, who by their writings endeavour to darken the truthe, and to persuade us that flying insects or any other animalcules can be produced from corruption!'”

  4. Zeke says:

    The Author’s refutation of the doctrine of equivocal or spontaneous generation in the instances of Sea Muscles, with a particular description of that species of Fish.

    I have been informed, that a books is published at Rome, by a learned Jesuit, named Philippo Bonanni, wherein he maintains, that animalcules, or small living creatures, can be produced out of inanimate substances, such as mud or sand, by spontaneous generation, according to the doctrine of Aristotle; and it seems that this learned gentleman is himself very desirous to see my observations on the subject. I shall therefore proceed to consider Signor Bonanni’s positions,
    and I doubt not, that upon investigation, they will be sound of no
    weight or substance, but will vanish like smoke or vapour.

    We will admit, that out of the mud or sand which is found on the sea-shore, or the beds of our rivers, at low water, shell-fish or testaceous animals come forth ; but it does not from thence by any means follow, that they are produced without any regular course of
    generation. Among the mud, in the ‘creeks or shallows of our sea coasts, are taken great quantities of shell-fish, called Muscles, which are used by us as an article of food; and, as I had in the autumn been employing myself in observations upon this species of fish, I applied to a fisherman who made it his business to catch Muscles, and questioned him as to what his opinion was, with regard to the propagation of that fish.

    This fisherman, who was a very intelligent man, and of good estimation in his profession, and had been brought up to it from his youth, informed me, that he had often experienced, that in the same tract of coast where he had found for several years successively very good Muscles, and in great abundance, yet afterwards in or about the same place, very few or none were to be got ; for which he assigned these reasons :

    ” At the time of the Muscles laying their eggs or spawn, which lasts but for a short season, this spawn, by strong tides and heavy gales of wind, will be carried from the places where it is deposited, and when the water becomes still and calm, it will sink to the bottom, or adhere to the weeds growing there ; and then in the space of two or three years, a good and plenteous Muscle-bank will be sormed in the place; adding, that by this means Muscles are taken where none were ever found before, and Muscle-banks formed of very great extent, the spawn laid by the Muscles being in such abundance, as to make the sea-water appear of a white colour.”

    If then, at the season when the Muscles deposit their eggs or spawn, we take up a quantity of the mud or sandy matter from the shore, and keep it covered with water, we need not wonder if we find Muscles or other shell-fish produced from thence; but if we imagine that this comes to pass by any other means than the ordinary course of generation, we shall therein deceive ourselves. And for my part, I hold it equally impossible for a small shell-Fish to be produced without generation, as for a whale to have its origin from the mud.”

  5. oldmanK says:

    Quote “Any one who ever discovered anything had to overthrow some doctrine of Aristotle or Ptolemy, put it that way.” It appears Ptolemy’s inheritance frequently comes under the lens for dubious ‘value’.

    But more than that there is a ‘psychological’ factor. ‘We’ prefer to make “gods” from material we feel -or know- is fake. It subconsciously gives us the liberty to do what we like.

    Quote “who were not a part of the educated class but who made many innovations”. In the world of ‘ancient language decipherment’ that is quite so. Perhaps they could ‘think outside the box’; they were also free of/from dogmatic gate-keeping.

  6. oldmanK says:

    Quote from here : (an interesting read -and long- from a quick look at the conclusions)

    “The currently favored theory on glacial-interglacial climate change was first proposed in 1864 by James Croll, a self-educated janitor at the Andersonian College in Scotland, which goes to show that anybody can do science. “

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