The Discovery of Microorganisms Revisited A close reading of 17th-century documents shows that Hooke, rather than Leeuwenhoek, was the first to observe a microorganism Howard Gest wo remarkable geniuses, Robert Preface of Micrographia and in a 1678 treatise, Hooke and Antonie van Leeuwen- Lectures and Collections; Microscopium. hoek, deserve the credit for discover- Hooke’s Preface to Micrographia also describes T ing microorganisms in the 17th cen- how to make a single-lens microscope of the tury. A complex series of events and same kind that Leeuwenhoek used in studies a common interest in microscopes were instru- that began almost a decade later. mental in leading these two men from very dif- According to my analysis along with the im- ferent backgrounds to codiscover the microbial portant studies of microscopist Brian Ford, universe. Their separate journeys into that realm Hooke rather than Leeuwenhoek was the first to were recorded between 1665 and 1678 in pub- observe and document the existence of a micro- lications of the Royal Society of London. organism. Moreover, his Micrographia pro- Among Hooke’s outstanding achievements is vided the basic model and “trigger” for Leeu- the first published description of a microorgan- wenhoek’s subsequent discoveries of other ism. From Hooke’s excellent drawing in Micro- microbes during the the 17th century. Thus, graphia (1665), mycologists identify Hooke’s Robert Hooke as well as Antonie van Leeuwen- specimen as the microfungus Mucor, the com- hoek should be considered responsible for “fa- mon bread mold (Fig. 1). In Micrographia, thering” modern microbiology. Hooke illustrated microscopic views of diverse biological objects, including sponges, wood, seaweed, leaf surfaces, hair, pea- A Glimpse of Robert Hooke’s cock feathers, fly wings, eggs of Illustrious Career silkworms, mites, a flea, and a Robert Hooke (1635–1703) was louse—as well as that of a mold. Robert Hooke as well as enrolled as an undergraduate at Hooke obtained the microfungus Christ Church College at the Uni- specimen from a “small white spot Antonie van versity of Oxford but apparently of a hairy mould,” many of which Leeuwenhoek never obtained a degree. Nonethe- he observed on the red sheepskin should be less, he became associated with a covers of a small book. He called the considered brilliant group of scholars, includ- organism a “microscopical mush- responsible for ing Christopher Wren and Robert Howard Gest is room.” Although he attempted to “fathering” Boyle, who met regularly to dis- Distinguished Pro- observe the “seed” (now called spo- cuss a broad range of scientific modern fessor Emeritus of rangiospores) from which it devel- problems. Microbiology and microbiology ops, the relatively low magnifying In due course, this group be- Adjunct Professor power of his microscope made that came the nucleus of the Royal So- of History and Phi- effort impossible. ciety. Hooke, a founding member losophy of Science Hooke advanced the techniques of micros- of the Society, served as “Curator of Experi- at Indiana Univer- copy in many ways that are detailed in the ments” from 1662–1677. His duties included sity, Bloomington. Volume 70, Number 6, 2004 / ASM News Y 269 FIGURE 1 tenary of Hooke’s death, several new biographies were published, describing his life and scientific achievements as well as his impor- tant architectural contributions while London was reconstructed following the Great Fire of 1666. Antonie van Leeuwenhoek’s Unusual Career Leeuwenhoek (1632–1723), who had little formal schooling, opened a shop at age 22 as a draper in Delft, Holland. Indeed, his scientific career likely traces to his use of low-power magnifying glasses to inspect cloth. Leeuwenhoek developed the ability to make superb micro- scopes containing single lenses Microscopic view of a “hairy mould” colony described by Robert Hooke in 1665 (in Micro- that were about 1 mm in diame- graphia). This image was the first published depiction of a microorganism. The reproductive structures (sporangia) are characteristic of the microfungus Mucor. Sporangia in different stages ter. Leeuwenhoek was a keen ob- are identified by the letters A, B, C, and D. Hooke included a scale reference; the length of the server and had extraordinary cu- bar under the diagram represents 1/32 of an inch. Image courtesy of The Lilly Library, Indiana riosity, which he soon focused on University, Bloomington. the natural world. For instance, he was the first to observe and describe sperm cells of animals, conducting “considerable experiments” and do- red blood cells, protozoa, and yeast cells. Al- ing other research projects officially recom- though it was then thought that maggots, fleas, mended to him. Hooke soon became a com- and the like formed through “spontaneous gen- manding intellectual force in the Society and, as eration,” he showed that such creatures hatch Curator, provided the main substance of many from eggs. meetings. During April 1663, Hooke lectured Leeuwenhoek communicated his observa- on the structure of plant tissues, such as cork tions to the scientific world in an unorthodox and moss, and coined the term “cell.” In Micro- way. Dutch acquaintances, who were corre- graphia, the structure of cork is detailed in Obs. sponding members of the Royal Society, sug- XVIII: “Texture of cork, and of the cells and gested that he describe his findings in letters pores of some other such frothy bodies.” addressed to the Society. During the rest of his Hooke’s scientific interests were broad, and life, Leeuwenhoek communicated some 200 let- his genius many sided. Physicist J. D. Bernal ters in Dutch, many of great length. Between wrote of Hooke in 1965 that his “interests 1939 and 1983 the “Leeuwenhoek Letters” ranged over the whole of mechanics, physics, were translated into English by large committees chemistry, and biology. He studied elasticity of Dutch scientists, yielding 11 volumes with and discovered what is known as Hooke’s English and Dutch texts on opposing pages. Law. .he invented the balance wheel, the use These volumes include extensive annotation. of which made possible accurate watches and Several footnotes show that Leeuwenhoek was chronometers; he wrote Micrographia, the first familiar with Micrographia even before he be- systematic account of the microscopic world, gan sending letters to the Royal Society. including the discovery of cells; he introduced One of Leeuwenhoek’s greatest contributions the telescope into astronomic measurement and to biology was the discovery of bacteria in 1676. invented the micrometer.” In 2003, the tercen- As might be expected, his observations and de- 270 Y ASM News / Volume 70, Number 6, 2004 Valuing Impact of History on Science, Witnessing Science’s Impact on History Howard Gest feels very strongly ily to America. He received a B.A. cessful, we felt about the impact of history on sci- in bacteriology from the University great pride in ence. “I believe that many young of California, Los Angeles (UCLA) our work; we scientists know little about the in 1942, and his Ph.D. from Wash- felt it was very early history of their own research ington University in 1949. While important for areas, and I think this limits their attending UCLA, he spent the sum- the security of understanding of how major dis- mers of 1941 and 1942 assisting the United coveries are made,” he says, adding Max Delbru¨ ck and Salvador Luria, States,” Gest that too often they assume that who were studying bacterial vi- says, recalling contemporary biological knowl- ruses. Although Gest began gradu- the Manhattan Howard Gest edge is nearly complete. “History ate work with Delbru¨ ck at Vander- Project. “But we clearly shows that biology is far bilt University, World War II were very disappointed in how the more complicated than each gener- intervened. Later in St. Louis, he bombs were used. We’d hoped they ation thinks it is.” did research with Alfred Hershey, would be used in such a way that Gest came to this realization using the radioactive isotope P32 to would not lead to the death of many years ago, influenced by the late examine what happens to phos- innocent civilians. And we were very J. H. “Jack” Hexter, a noted histo- phorus-containing cell components perturbed that the petition never rian and professor of history at when bacterial viruses replicate. reached President Truman.” Washington University, St. Louis, These studies culminated with their Gest has served on the faculties Mo., where Gest knew him, and discovery of P32 “suicide” of bacte- of Case Western Reserve University Yale University, New Haven, riophage. in Cleveland, Ohio, Washington Conn. “Hexter once said: ‘History During World War II, Gest was University, and Indiana University, with a capital H deals with major involved in the Manhattan Project and has been a visiting researcher at trends, large movements, deep run- with physical chemist Charles the California Institute of Technol- ning tides, portentous rumbles. Coryell—one of Gest’s teachers at ogy, Dartmouth Medical School, When a “small h” historian fixes UCLA—first at the University of Stanford University, Oxford Uni- his attention on a fragment of the Chicago, and later at Oak Ridge, versity, Tokyo University, and past washed up on the littered Tenn. His role was to conduct basic UCLA. He was twice named a beach of the present, he is likely to research on the radioactive ele- Guggenheim Fellow and has served ask simple questions about it: How ments formed in uranium fission. on a number of advisory commit- did it get there? What the devil is it? He looks back at that period with tees of the U.S. government. During What was it for? Where is it from? conflicted emotions. While proud his second Guggenheim fellowship, What happened to it?’,” Gest says. of his contribution toward devel- he studied problems of biochemical “Hexter’s remarks made me realize oping the atomic bomb, he was evolution as a member of the Pre- that I had become a ‘small h’ histo- troubled by the real possibility that cambrian Paleobiology Group.