Marc J. Ratcliff, The Quest for the Invisible: Microscopy in the Enlightenment (Farnham: Ashgate, 2009), pp. xvi + 315, £60.00/$124.95, hardback, ISBN: 978-0-7546-6150-4.

Traditionally, historians of microscopy considered the eighteenth century ‘the lost century’ – Brian J. Ford, Revealing Lens (London: Harrap, 1973) – a time of decline in microscopy research, bookended by a burst of activity in the seventeenth century with the work of Leeuwenhoek, Malpighi, and others, and the rise of microscopy to a position of scientific prominence in the nineteenth century. Historians have attributed the nineteenth-century resurgence to the development of the compound achromatic microscope and the emergence of cell theory in the 1830s, culminating in the era of microbiology in the second half of the century. Using manuscript and printed sources not consulted by others, Marc Ratcliff revises this interpretation, contending that the eighteenth century was a time of serious microscopy research, primarily in the natural sciences. Jutta Schickore made the same point in her recent book, The Microscope and the Eye: A History of Reflections, 1740–1870 (Chicago: University of Chicago Press, 2007), but Ratcliff provides much more detail. Ratcliff tells his story of eighteenth-century microscopy in three parts. In Part I, 1680–1740, researchers sought to determine what constituted a good microscopical object. At first they focused on animalcules, an approach inherited from the previous century, but these invisible organisms could not provide a shared viewing experience. By the end of this period, investigators had settled on insects and seeds, both visible with the naked eye, but whose viewing could be perfected and enhanced by the use of the microscope. They could also share what they saw and communicate their findings. From 1740 to the 1760s (Part II) there was a turning point in the history of microscopy, exemplified by the work of Abraham Trembley, whose polyp aroused enthusiasm throughout Europe because of its ability to regenerate itself. Trembley made major contributions to the shared research effort; for example, he developed ways of shipping living organisms for shared viewing. This era also witnessed the development of the experimental research laboratory and the experimental report to which Trembley made important contributions. During these years the modern experimental report became commonplace. According to Ratcliff, Trembley was ‘the major driving force for the 1740’s take-off in microscopical research’ (p. 117). After the polyp, microscopy research moved into marine zoology and other areas of investigation. By the end of the century (Part III), microscopy researchers took up the ‘quest for the invisible’ by turning their attention to infusoria, objects only visible with the microscope. This new focus posed classification problems, since Linnaeus’ classification system could not easily accommodate infusoria. The Danish researcher, Otto-Friedrich Muller, developed his systematics of infusoria by applying the canons of modern natural history to known microscopic species. Muller’s influence was great: he was the first to classify animalcules according to the Linnean system and in accordance with the extant physiological knowledge. His Animalcula Infusoria provided a foundation for microscopical zoology into the 1820s. Muller’s work allowed a whole community of microscopy researchers to constitute itself around the invisible, now that they had a common language and a systematic model to enable communication. Overall, Ratcliff de-emphasises social and political explanations commonly used by sociologists and historians to explain science, arguing that communication and cognition were constitutive of eighteenth-century microscopy. Communication was key to the formation of a European-wide research community. Journals were the vehicle, along with scholarly societies, exchanges between individual scholars, letters, handbooks, reports, and specimens. Ratcliff argues that the ‘the lost century’ was a construction by nineteenth-century microscopy researchers who sought to distance themselves from the ‘amateur’ work of predecessors, conducted on what they considered inferior instruments. These microscopists judged the results of eighteenth-century research as unsophisticated compared with nineteenth-century advances in cellular theory and pathology. This book will be indispensable for historians of microscopy and eighteenth-century natural science. Historians of medicine will find the book of interest, although the focus is not on medical microscopy. Two chapters on microscopes in the market-place provide a context for understanding microscopy questions and research. Copious illustrations and tables enhance the reader’s understanding of the eighteenth-century microscopy enterprise. The book has some weaknesses. Sloppy copy-editing detracts from the reader’s experience. Furthermore, Ratcliff may have included too much information: the book is dense. All in all, however, Ratcliff deserves much credit for this fine scholarly monograph.