A remarkable feat of textual synthesis, The Germ of an Idea: Contagionism, Religion, and Society in Britain, 1660-1730 (Palgrave Macmillan, 2016) traces the complex narrative of emerging medical theories of disease and their relationship to physicians’ fractured, fractious religious and social alliances in this period. Margaret DeLacy, a Harvard- and Princeton-trained independent scholar who has written extensively about medical history and contagionism, acknowledges drawing on “a reference base of thousands of books and articles” (xix) over decades of research to answer a single question: Why were medical thinkers “diverted” from pursuing “the germ-theory of disease” in the early-eighteenth century, when clearly several had earlier amassed evidence that “should have made possible the formulation” (iv) of germ-theory developed only much later, in the nineteenth century? The answer is neither simple nor straightforward, but DeLacy tells the story in nine meticulously annotated chapters, each helpfully structured with clearly-marked introductions and conclusions.
Grounding the reader, as well as showing what may have precipitated this perceived lull in scientific progress, Chapter 1 features a historical survey of contagionism prior to 1660. The belief that disease spreads through some contagion reaches back to classical times, although the notion that these contagions might be living agents remained uncommon in the mid-seventeenth century. In England during the mid-seventeenth century (Chapter 2) major religious and social changes during the Restoration caused abruptions in medical education and professions. As part of the Clarendon Code (1661), religious Nonconformists were denied degrees from Cambridge and Oxford. Only MDs from these universities were permitted to become Fellows of the London College of Physicians—the Galenic institution that held the legal authority to regulate physicians in and around London. Thus, Dissenters were forced to seek medical degrees abroad and were prevented (in theory) from reaching the top of their profession in Britain.
But the Code prompted unintended positive consequences. English doctors who trained abroad were exposed to wider schools of thought and more modern, diverse curricula that went beyond Galenism. Like their overseas counterparts who were escaping religious or political persecution in their countries, these physicians brought an entrepreneurial and cosmopolitan spirit to medical practice in England.
In the chapters that follow, DeLacy effectively demonstrates that, despite being an idea entertained by many British medical authors in the decades before 1730, contagionism as an ideology did not, could not take hold. The infrastructure and research community necessary to investigate and sustain a shared vision of contagium vivum did not yet exist. In the process of proving this conclusion, DeLacy unfolds complex and wide-ranging evidence by piecing together these dissimilar authors’ ideas: from unorthodox medical populists, to well-known Restoration physicians like Thomas Sydenham, Hans Sloane, Benjamin Marten. With patience and persistence she has achieved the theoretical coalescence that these thinkers, constrained by the limitations of their time, could not.
No light reading, this text makes demands on its audience. Readers could quibble with the intricacy of detail, which at times seems to overlap and fold in on itself, as DeLacy describes complicated notions of disease transmission in this era and the proponents, partial supporters, and opponents of these concepts (along with their own theories). But most details are vivid and fascinating, especially those that take readers up close to the practice of early modern medicine. During an experiment in early microscopy, one physician observed “‘whales’ or ‘dolphins’ swimming in the blood” (39). Several atomists wrote of “seed” theories, and DeLacy recounts excerpts from unpublished diaries and letters that show beliefs that “’The Air is full of the Seed of Worms’” and worms had been found “in the blood, as also in the hairs of the body, and others in the intestines’” (75, 74). Later chapters focus on terrifying diseases such as consumption, smallpox, and plague, and consider dilemmas of early preventive measures like inoculation and quarantine.
The book’s importance to historians of this era and medical historians especially is self-evident, because it occupies a lacuna in the scholarship. As the author shows in a prefatory literature review, “no recent historian seems to have revisited the claim that contagionism was all but dead in the early eighteenth century” (xiv); this book fills that gap admirably. Humanities scholars from several other fields—religion, philosophy, literature—will find DeLacy’s work helpful, even revelatory, as she sifts through the competing theoretical frameworks and linguistic differences of medical writings at this time, collating and clarifying disparate texts into a unified account that identifies physicians’ links to other great thinkers (e.g. Milton, Locke, Swift, and Pope). Although this book is written for scholarly audiences and densely packed, it is clear and accessible to general readers with avid interest in medical history.
For Health Humanities professionals, this book underscores—with a twist—one of the primary lessons we hope to teach our medical students. Just as we nudge them to consider the “whole patient,” including the familial, social, cultural, and even religious influences that inform the narrative he tells when recounting his medical history, this book urges us to consider the “whole physician” and the innumerable obstacles and opportunities that she may have navigated to become the thinker and clinician she is today.
Sandra G. Weems is an Adjunct Lecturer at University of Florida in Gainesville. She holds a PhD in English literature, with an interdisciplinary focus in medical humanities. Her research interests include traumatology, illness narratives, and the clinical uses of reflective writing.