A short history of nearly everything - Bill Bryson [188]
Among the microscopic features first identified by Hooke were little chambers in plants that he called “cells” because they reminded him of monks' cells. Hooke calculated that a one-inch square of cork would contain 1,259,712,000 of these tiny chambers—the first appearance of such a very large number anywhere in science. Microscopes by this time had been around for a generation or so, but what set Hooke's apart were their technical supremacy. They achieved magnifications of thirty times, making them the last word in seventeenth-century optical technology.
So it came as something of a shock when just a decade later Hooke and the other members of London's Royal Society began to receive drawings and reports from an unlettered linen draper in Holland employing magnifications of up to 275 times. The draper's name was Antoni van Leeuwenhoek. Though he had little formal education and no background in science, he was a perceptive and dedicated observer and a technical genius.
To this day it is not known how he got such magnificent magnifications from simple handheld devices, which were little more than modest wooden dowels with a tiny bubble of glass embedded in them, far more like magnifying glasses than what most of us think of as microscopes, but really not much like either. Leeuwenhoek made a new instrument for every experiment he performed and was extremely secretive about his techniques, though he did sometimes offer tips to the British on how they might improve their resolutions.*40
Over a period of fifty years—beginning, remarkably enough, when he was already past forty—he made almost two hundred reports to the Royal Society, all written in Low Dutch, the only tongue of which he was master. Leeuwenhoek offered no interpretations, but simply the facts of what he had found, accompanied by exquisite drawings. He sent reports on almost everything that could be usefully examined—bread mold, a bee's stinger, blood cells, teeth, hair, his own saliva, excrement, and semen (these last with fretful apologies for their unsavory nature)—nearly all of which had never been seen microscopically before.
After he reported finding “animalcules” in a sample of pepper water in 1676, the members of the Royal Society spent a year with the best devices English technology could produce searching for the “little animals” before finally getting the magnification right. What Leeuwenhoek had found were protozoa. He calculated that there were 8,280,000 of these tiny beings in a single drop of water—more than the number of people in Holland. The world teemed with life in ways and numbers that no one had previously suspected.
Inspired by Leeuwenhoek's fantastic findings, others began to peer into microscopes with such keenness that they sometimes found things that weren't in fact there. One respected Dutch observer, Nicolaus Hartsoecker, was convinced he saw “tiny preformed men” in sperm cells. He called the little beings “homunculi” and for some time many people believed that all humans—indeed, all creatures—were simply vastly inflated versions of tiny but complete precursor beings. Leeuwenhoek himself occasionally got carried away with his enthusiasms. In one of his least successful experiments he tried to study the explosive properties of gunpowder by observing a small blast at close range; he nearly blinded himself in the process.
In 1683 Leeuwenhoek discovered bacteria, but that was about as far as progress could get for the next century and a half because of the limitations of microscope technology. Not until 1831 would anyone first see the nucleus of a cell—it was found by the Scottish botanist Robert Brown, that frequent but always shadowy visitor to the history of science. Brown, who lived from 1773 to 1858, called it nucleus from the Latin nucula, meaning little nut or kernel. Not until 1839, however, did anyone realize that all living matter is cellular. It was Theodor Schwann, a German, who had this insight, and it was not only comparatively late, as scientific insights go, but not widely embraced at first.