Leeuwenhoek: Independent Scholar Part II

Letters to the Royal Society

Reinier de Graaf, Leeuwenhoek’s friend and fellow townsman was very interested in his talent for making lenses. He was responsible for the first communication of van Leeuwenhoek's work to the Royal Society of London (the oldest public institution devoted to the pursuit of scientific research). On April 28, 1673, de Graaf wrote to Henry Oldenburg, the Society’s first secretary and one of its founding members:

“. . . I am writing to tell you that a certain most ingenious person here, named Leeuwenhoek, has devised microscopes which far surpass those which we have hitherto seen…The enclosed letter from him, wherein he describes certain things which he has observed more accurately than previous authors, will afford you a sample of his work. …and if it please you and you would test the skill of this most diligent man and give him encouragement, then send him a letter containing your suggestions, and proposing to him more difficult problems of the same kind.”

Leeuwenhoek’s first letter to the Royal Society contained descriptions of fungi and the sting and mouthparts of a bee, among other things. His letter was well received. Oldenburg translated it and submitted it for what scientists and scholars today call peer review. It was published in the Philosophical Transactions of the Royal Society which continues to be published today. Many of his first observations followed in the footsteps of ideas from Hooke’s Micrographia.

Ford tells us that fourteen months later, on June 1, 1674, Leeuwenhoek sent his fourth letter to the Society, a folio of six pages. The last sheet of the letter had a small envelope pasted to it that contained four smaller paper packets. The packets contained finely cut sections that Leeuwenhoek had prepared by his own hand for the interest of the Royal Society. These were the first four packets that Ford discovered after 304 years.

Leeuwenhoek almost lost his credibility when he sent his observations of microscopic single celled organisms. Their existence at that time was not even imagined. It caused a sensation. This letter, dated October 9, 1676, is often called the pepper-water letter or “letter on protozoa.” It describes what he saw over time in a series of experiments with different peppers dissolved in water. Even though he had already established his reliability, the Society had to send observers to verify that he was indeed seeing what he reported and could still be trusted. After he was vindicated, he was made a full member of the Royal Society in 1680.

On September 17, 1683, Leeuwenhoek wrote to the Society about his observations on the plaque from his teeth, "I then most always saw, with great wonder, that in the said matter there were many very little living animalcules, very prettily a-moving. . . had a very strong and swift motion, and shot through the water."

Work Continues

Recognition and fame did not change Leeuwenhoek. He continued to work with the same enthusiasm throughout his life. At age 85 he wrote, “Tis my intention to inquire into these marvelous structures more narrowly, for my own pleasure.”

For fifty years, up until the weeks before his death on August 26, 1723, at age 90, he sent his letters to the Royal Society regularly, along with drawings prepared by a draftsman. It is believed that he wrote more than 500 letters to the Royal Society and other scientific institutions.

He recorded his observations and explanations in his diary in great detail. He wrote in simple language, as if talking to a friend. The detailed descriptions of his preparation steps seemed to be that of a trained scientist. He observed and set forth conclusions that he believed were supported by the data. If he was later proved wrong, he was honest and willing to change his mind. It seems he wanted only to search for the truth objectively which is the hallmark of a scientist.

So we come full circle back to Ford’s discovery of specimens which prove that Antonie van Leeuwenhoek’s real legacy is his truly scientific approach to research and his love of learning, not just the lenses he made and used. He brought into view a whole new world of tiny “animalcules” as he called them, which had never been seen before. Think where we would be if we did not know about the world he saw—if he had not pursued his life’s passion. His words say it best:

In a 1715 letter he noted: "Some go to make money out of science, or to get a reputation in the learned world. But in lens-grinding and discovering things hidden from our sight, these count for nought. And I am satisfied too that not one man in a thousand is capable of such study, because it needs much time ... and you must always keep thinking about these things if you are to get any results. And over and above all, most men are not curious to know: nay, some even make no bones about saying, What does it matter whether we know this or not?"

Are these not the words of the ultimate lifelong learner and independent scholar?