Our story of Antoni van Leeuwenhoek, “the Father of Microbiology” and lifelong learner, begins not with his birth in 1632, but in 1981 when biologist Brian J. Ford discovered some of Leeuwenhoek’s original specimens, long overlooked among his letters at the Royal Society in London.

Those specimens were found to be in great condition, extremely well preserved, so that Ford was able to carry out observations with a range of modern microscopes, as well as the original Leeuwenhoek microscope in the Netherlands at the Utrecht University Museum.

So how did we get to Ford’s discovery more than 300 years after the death of this gentleman scientist who succeeded in making some of the most important discoveries in biology?

Preparation for a Life’s Study

Antoni van Leeuwenhoek (layu-wen-hook) was born in Delft, the Netherlands, on October 24, 1632. Little is known of Leeuwenhoek's early life, but it seems very certain that he did not have an in-depth education in science. In 1648, when he was just 16 years old, he secured an apprenticeship with a Scottish cloth merchant in Amsterdam.

After six years or so he returned to Delft to start his own fabric business. He purchased a house and an adjoining shop where he spent the rest of his life.

In 1668 Leeuwenhoek had traveled to London, where it is thought that he must have seen and been inspired by a copy of Robert Hooke’s Micrographia.

By 1670, at the age 39, he was financially secure enough to devote his time to research with the microscopes he created. Leeuwenhoek would have used magnifying lenses to examine the quality of cloth he bought--but now he was ready to pursue microscopy in earnest. We don’t know what his independent study consisted of up to this point in his life, but from this time forward his course is documented in his journals and in his letter to the Royal Society of London for the Improvement of Natural Knowledge.

Leeuwenhoek is thought to have made over 500 microscopes, of which nine have survived today. Probably all of Leeuwenhoek's instruments were simply powerful magnifying glasses. Compared to modern microscopes, they are extremely simple. They use only one lens, mounted in a tiny hole in the brass plate that is the body of the instrument. Amazingly, the entire microscope is only 3-4 inches long.

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.

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. It was translated 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.

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."

Lifelong Passion

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.

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 didn't know about the world he saw—if he had not pursued his life’s passion.

Gives a senior something to ponder, doesn’t it.