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e law。 hookeachieved many things in his sixty…eight years—he was both an acplished theoretician anda dab hand at making ingenious and useful instruments—but nothing he did brought himgreater admiration than his popular book microphagia： or some physiological descriptions ofminiature bodies made by magnifying glasses； produced in 1665。 it revealed to an enchantedpublic a universe of the very small that was far more diverse； crowded； and finely structuredthan anyone had ever e close to imagining。
among the microscopic features first identified by hooke were little chambers in plantsthat he called “cells” because they reminded him of monks’ cells。 hooke calculated that aone…inch square of cork would contain 1；259；712；000 of these tiny chambers—the firstappearance of such a very large number anywhere in science。 microscopes by this time hadbeen around for a generation or so； but what set hooke’s apart were their technicalsupremacy。 they achieved magnifications of thirty times； making them the last word inseventeenth…century optical technology。
so it came as something of a shock when just a decade later hooke and the other membersof london’s royal society began to receive drawings and reports from an unlettered linendraper in holland employing magnifications of up to 275 times。 the draper’s name wasantoni van leeuwenhoek。 though he had little formal education and no background inscience； 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 simplehandheld devices； which were little more than modest wooden dowels with a tiny bubble ofglass embedded in them； far more like magnifying glasses than what most of us think of asmicroscopes； but really not much like either。 leeuwenhoek made a new instrument for everyexperiment he performed and was extremely secretive about his techniques； though he didsometimes offer tips to the british on how they might improve their resolutions。
2over a period of fifty years—beginning； remarkably enough； when he was already pastforty—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 simplythe facts of what he had found； acpanied by exquisite drawings。 he sent reports on almosteverything 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 unsavorynature）—nearly all of which had never been seen microscopically before。
after he reported finding “animalcules” in a sample of pepper water in 1676； the membersof the royal society spent a year with the best devices english technology could producesearching for the “little animals” before finally getting the magnification right。 whatleeuwenhoek had found were protozoa。 he calculated that there were 8；280；000 of these tinybeings in a single drop of water—more than the number of people in holland。 the worldteemed with life in ways and numbers that no one had previously suspected。
inspired by leeuwenhoek’s fantastic findings； others began to peer into microscopes withsuch keenness that they sometimes found things that weren’t in fact there。 one respecteddutch observer； nicolaus hartsoecker； was convinced he saw “tiny preformed men” in spermcells。 he called the little beings “homunculi” and for some time many people believed that allhumans—indeed； all creatures—were simply vastly inflated versions of tiny but pleteprecursor beings。 leeuwenhoek himself occasionally got carried away with his enthusiasms。
in one of his least successful experiments he tried to study the explosive properties ofgunpowder by observing a small blast at close range； he nearly blinded himself in the process。
2leeuwenhoek was close friends with another delft notable； the artist jan vermeer。 in the mid…1660s； vermeer；who previously had been a petent but not outstanding artist； suddenly developed the mastery of light andperspective for which he has been celebrated ever since。 though it has never been proved； it has long beensuspected that he used a camera obscura； a device for projecting images onto a flat surface through a lens。 nosuch device was listed among vermeers personal effects after his death； but it happens that the executor ofvermeers estate was none other than antoni van leeuwenhoek； the most secretive lens…maker of his day。
in 1683 leeuwenhoek discovered bacteria； but that was about as far as progress could getfor the next century and a half because of the limitations of microscope technology。 not until1831 would anyone first see the nucleus of a cell—it was found by the scottish botanistrobert brown； that frequent but always shadowy visitor to the history of science。 brown； wholived 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 theodorschwann； a german； who had this insight； and it was not only paratively late； as scientificinsights go； but not widely embraced at first。 it wasn’t until the 1860s； and some landmarkwork by louis pasteur in france； that it was shown conclusively that life cannot arisespontaneously but must e from preexisting cells。 the belief became known as the “celltheory；” and it is the basis of all modern biology。
the cell has been pared to many things； from “a plex chemical refinery” （by thephysicist james trefil） to “a vast； teeming metropolis” （the biochemist guy brown）。 a cell isboth of those things and neither。 it is like a refinery in that it is devoted to chemical activityon a grand scale； and like a metropolis in that it is crowded and busy and filled withinteractions that seem confused and random but clearly have some system to them。 but it is amuch more nightmarish place than any city or factory that you have ever seen。 to begin withthere is no up or down inside the cell （gravity doesn’t meaningfully apply at the cellularscale）； and not an atom’s width of space is unused。 there is activity every where and aceaseless thrum of electrical energy。