Rocky Road: Leeuwenhoek

Leeuwenhoek

From Ingenious Pursuits: Building the Scientific Revolution by Lisa Jardine

I have had several gentlewomen in my house, who were keen on seeing the little eels in vinegar: but some of 'em were so disgusted at the spectacle, that they vowed they'd ne'er use vinegar again. But what if one should tell such people in the future that there are more animals living in the scum on the teeth in a man's mouth, than there are men in a whole kingdom?

A minor official in the city of Delft, Antoni van Leeuwenhoek had few of the prerequisites for scientific greatness. Speaking only Low Dutch (not even High Dutch), he had no formal scientific training. In fact, he had hardly any education at all. What he did have was a copy of Robert Hooke's Micrographia and a passion for all things tiny. Using his own homemade single-lens microscope — an instrument so small it could easily fit in the palm of your hand with a thumb-sized wooden paddle and a bead of a lens — Leeuwenhoek observed everything he could imagine. He eventually made more than 500 microscopes, and making diminutive, single-lens versions actually gave him better magnification than the larger, multi-lens microscopes in common use at the time. Leeuwenhoek's microscopes achieved a magnification up to 275 times, and they enabled him to see life where nobody thought living things existed. The scum on a man's teeth, for instance. He couldn't draw any better than he could write foreigners in their own language, but he collaborated with unnamed artists from Delft to produce exquisite illustrations, such as this drawing of a bee organ.

Leeuwenhoek's observations soon attracted the attention of the Dutch diplomat Sir Constantijn Huygens. In 1673, the English and Dutch were at war, but that didn't discourage Huygens from writing Robert Hooke, a member of the Royal Society of London, to introduce Leeuwenhoek. Like many of his fellow Englishmen, however, Hooke disdained the efforts of a foreigner, and refused to answer Huygens's letter. Undaunted, Huygens wrote another Royal Society member, Henry Oldenburg. Partly because he was responsible for the Royal Society's correspondence, and partly because he liked to stir up controversy — especially where Hooke was concerned — Oldenburg gladly answered Huygens and apologized for Hooke's bad manners. It proved to be the beginning of a fruitful correspondence between Leeuwenhoek and the Royal Society, one that lasted nearly 50 years, in which Leeuwenhoek produced hundreds of papers. Even Hooke eventually came around, and started learning Dutch to better understand Leeuwenhoek's works.

From Seeing Further edited by Bill Bryson

When observing pepper, under the assumption that it had microscopic spikes to produce its effect on the tongue (he was wrong, it didn't), Leeuwenhoek made an accidental discovery: tiny organisms, known today as protozoa. (Shown at right are rotifers: similarly small organisms, these with parasitic worms.) When the Royal Society was able to reproduce his experiment, Leeuwenhoek became an instant celebrity. Not surprisingly, the self-taught microscopist developed considerable self-confidence, enough to irritate at least one contemporary. Jan Swammerdam once remarked, "It is impossible to go into a discussion with Leeuwenhoek as he is biased and reasons in a very barbaric way, having no academic education."

While others worked at replicating his results, Leeuwenhoek kept finding little animals everywhere, including "many very little living animacules, very prettily a-moving" in dental plaque. His doggedness was matched by his lack of squeamishness. He nearly blinded himself once when trying to observe a small gunpowder blast at close range. While studying the development of lice, he carried louse families in his stockings, allowing them to feast on his own flesh. He expected comparable sacrifices from his wife, who had to keep insect eggs warm by carrying them in her bosom.

On one occasion, Leeuwenhoek wrote the Royal Society that describing a water sample loaded with such a great quantity of "animacules" that "all the water . . . seemed to be alive." It was unfortunate that the savants who marveled at the tiny organisms Leeuwenhoek found couldn't grasp their significance in causing disease. Two centuries — and thousands of deaths from dysentery, cholera, and typhoid — passed before anyone made the connection between winsome creatures swimming in drinking water and deadly diseases.

For more information:
Ingenious Pursuits: Building the Scientific Revolution by Lisa Jardine
The Curious Life of Robert Hooke by Lisa Jardine
The Great Naturalists edited by Robert Huxley
The Forgotten Genius by Stephen Inwood
Chrysalis by Kim Todd
Matters of Exchange by Harold J. Cook
Chance in the House of Fate by Jennifer Ackerman
Joseph Leidy: The Last Man Who Knew Everything by Leonard Warren
Wonders and the Order of Nature by Lorraine Daston and Katharine Park
Seeing Further edited by Bill Bryson
A Short History of Nearly Everything by Bill Bryson
"Little Worms Which Propagate Plague" in The Journal of the Royal College of Physicians of Edinburgh
The Feejee Mermaid by Jan Bondeson
The Scientific Revolution by Steven Shapin