Oct 242017

Today is the birthday (1632) of Antonie Philips van Leeuwenhoek, is commonly known as “the Father of Microbiology” because of his contributions toward the establishment of microbiology as a scientific discipline. He was not a trained scientist and so for some time labored under the label of “gifted amateur” and was treated as something of an unsystematic adventurer until his full notes were reviewed and published, upon which it was abundantly clear that he rivaled or surpassed any other scientist in the field in his day.  In fact, the negative view of him may have been spread by the likes of Robert Hooke (discoverer of plant cells) — https://www.bookofdaystales.com/robert-hooke/ — who spent his own scientific career battling for recognition against the slanders of Isaac Newton. This was not only an age of scientific discovery, but also an age of deep jealousy and competition. Such jealousies and slanders were actually unnecessary in Leeuwenhoek’s case because he was not interested in building a scientific career; he just wanted the world to know what he had discovered.

Leeuwenhoek’s life fascinates me when I think of what he saw for the first time: a microscopic world teeming with hitherto unknown life, rivaling the great voyages of discovery of Dutch explorers of the time. I still get a huge kick out of using a microscope. It’s one thing to see images of insect wings or sand under a microscope on the internet or in books. It is quite another to peer into a microscope with your own eyes and witness them for yourself. Just this year I introduced primary school students in Myanmar to microscopy and I was delighted to see how enthralled they all were.  Imagine what it was like for Leeuwenhoek seeing single-celled organisms for the first time in a drop of pond water.

Leeuwenhoek was born in Delft in the Dutch Republic and lived there most of his life. His father, Philips Antonisz van Leeuwenhoek, was a basket maker who died when Antonie was only five years old. His mother, Margaretha (Bel van den Berch), came from a well-to-do brewer’s family. She remarried Jacob Jansz Molijn, a painter, but when Leeuwenhoek was around 10 years old his step-father died. He attended school in Warmond for a short time before being sent to live in Benthuizen with his uncle, an attorney. At the age of 16 he became a bookkeeper’s apprentice at a linen-draper’s shop in Amsterdam. He left there after six years.

Van Leeuwenhoek married Barbara de Mey in July 1654, with whom he fathered one surviving daughter, Maria (four other children died in infancy). That same year he returned to Delft, where he remained for the rest of his life. He opened a draper’s shop, which he ran throughout the 1650s. His wife died in 1666, and in 1671 he remarried. His status in Delft steadily grew. In 1660 he received a lucrative job as chamberlain for the assembly chamber of the Delft sheriffs in the city hall, a position he held for almost 40 years. In 1669 he was appointed as a land surveyor by the court of Holland; at some point he combined it with another municipal job, being the official “wine-gauger” of Delft and in charge of the city wine imports and taxation. Leeuwenhoek was a contemporary of another famous Delft citizen, Johannes Vermeer, who was baptized just four days earlier. They must have been more than simple acquaintances because Leeuwenhoek acted as the executor of Vermeer’s will after the painter died in 1675.

While running his draper shop, Leeuwenhoek wanted to see the quality of the thread better than possible using magnifying lenses then available. He began to develop an interest in lens making, although few records exist of his early activity. His 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. Leeuwenhoek did not invent the microscope (who did is still unknown), but through his own experimentation he invented a microscope with magnifications far superior to anything else available at the time, making it possible for him to view and record microscopic organisms that were completely unknown.

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.

After developing his method for creating powerful lenses and applying them to the 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 editor of the journal, Henry Oldenburg, with a ringing endorsement of van Leeuwenhoek’s microscopes which, he claimed, “far surpass those which we have hitherto seen”. In response, in 1673 the society published a letter from Leeuwenhoek that included his microscopic observations on mold, bees, and lice.

Leeuwenhoek’s work fully captured the attention of the Royal Society, and he began corresponding regularly with the society regarding his observations. At first he had 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. By the time van Leeuwenhoek died in 1723, he had written around 190 letters to the Royal Society, detailing his findings in a wide variety of fields, centered on his work in microscopy. He only wrote letters in his own colloquial Dutch; he never published a proper scientific paper in Latin. He strongly preferred to work alone, distrusting the sincerity of those who offered their assistance. The letters were translated into Latin or English by Henry Oldenburg, who had learned Dutch for this very purpose. Despite the initial success of van Leeuwenhoek’s relationship with the Royal Society, soon relations became 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 some skepticism.

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 that might require reform. Finally, in 1677, Leeuwenhoek’s observations were fully acknowledged by the Royal Society. When Leeuwenhoek was nominated for membership of the Royal Society in February 1680 he was reportedly “taken aback” by 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.

By the end of the 17th century, Leeuwenhoek had a virtual monopoly on microscopic study and discovery. He was visited over the years by many notable individuals including tsar Peter the Great, Leibniz, William III of Orange and his wife, Mary II of England, and the burgemeester Johan Huydecoper of Amsterdam, the latter being very interested in collecting and growing plants for the Hortus Botanicus Amsterdam. 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. Leeuwenhoek was an astute businessman and he believed 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 200 or more microscopes with different magnifications over the course of his life.

Leeuwenhoek’s single-lens microscopes were relatively small devices, the largest being about 5 cm long. They are used by placing the lens very close in front of the eye, while looking in the 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 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 studied a broad range of microscopic phenomena, and shared the resulting observations freely with other scientists. He wrote over 560 letters to the Royal Society, for example. In modern terms some of his main discoveries were:

infusoria (protists in modern zoological classification), in 1674

bacteria, (especially large Selenomonads from the human mouth), in 1683

the vacuole of plant cells, in 1676

spermatozoa, in 1677

the banded pattern of muscular fibers, in 1682

Even during the last weeks of his life, van Leeuwenhoek continued to send letters full of observations to London. The last few contained a precise description of his own illness. He suffered from a rare disease, an uncontrolled movement of the abdomen, which now is named van Leeuwenhoek’s disease. He died at the age of 90, on 26 August 1723, and was buried four days later in the Oude Kerk in Delft.

Delft, despite its illustrious history as a city famed for tableware, does not have a particularly illustrious history as a center for cuisine. For all of Vermeer’s luscious still lifes with food, the dishes the ingredients were made into are fairly straightforward. Dutch food of the 17th century was a trifle ordinary. There is stamppot, however, which might appeal to you. In its own way it’s Dutch comfort food with a venerable history. At heart stamppot is potato and cabbage mashed, together with other vegetables, and perhaps some meat added as the cook prefers. Among food travelers the Dutch are well known for liking to mash their food.  But we have to make a distinction here that the Dutch themselves make. On the one hand, some traditional Dutch dishes are served mashed; on the other hand, some Dutch people like to mash up meals on their plates after the ingredients have been served whole. The Dutch  consider the two methods to be quite different, and I do too. In the first case the dish is mixed and mashed as the cook desires, in the second case it is diner’s choice. Stamppot is served mashed. But the mashing process does not produce a smooth purée. It is quite deliberately lumpy. It is customary to serve stamppot with some meat such as grilled or fried Rookworst, or some other spicy sausage. It can also be served on its own. As long as you have cabbage and potatoes the other vegetables are up to you. I’ve given a fair mix here. White cabbage is traditional but you can use any greens you want: kale, spinach, collards, etc.



2 lbs potatoes, peeled and diced
3 large carrots, peeled and diced
2 large parsnips, peeled and diced
1 large turnip, peeled and diced
1 large leek, washed well and chopped
1 onion, peeled and chopped
1 lb savoy cabbage (or greens of choice), coarsely shredded
½ cup butter
salt and pepper
½ cup chopped fresh parsley leaves


Place the chopped vegetables in a large stock pot, and add water to barely cover. Place the pot over high heat, cover, bring to the boil, then reduce the heat and simmer until the vegetables are tender, around 20 minutes.

Drain the vegetables well and then mash them with a fork, not too smoothly. Leave some lumps. Season the mash with salt and pepper to taste, and then add the butter and stir it through well. Stir in the chopped parsley.

Serve the stamppot topped with grilled, sliced sausage if you want. You can also add an extra knob of butter.