New book review: Jole Shackelford’s history of chronobiology for H-Environment
I was delighted to be commissioned to write a review of the third installment of Jole Shackelford’s sweeping history of chronobiology by H-Environment, H-Net Reviews. H-Environment is a wonderful open platform for environmental history featuring resources, calls for papers, book reviews, grants and more. You can read my review for free here and it is also reproduced below.
Shackelford, Jole. An Introduction to the History of Chronobiology, Vol. 3, The Search for Biological Clocks: Metaphors, Models, and Mechanisms. Pittsburgh: University of Pittsburgh Press, 2022. 400 pp. $60.00 (cloth), ISBN 9780822947332.
Reviewed by Kristin Hussey (Newcastle University)
Published on H-Environment (July, 2024)
Commissioned by Daniella McCahey (Texas Tech University)
Printable Version: https://www.h-net.org/reviews/showpdf.php?id=60748
The Search for Biological Clocks: Metaphors, Models and Mechanisms is the third and final installment of American historian of science Jole Shackelford's sweeping history of chronobiology for University of Pittsburgh Press. Chronobiology is a branch of the biological sciences still obscure enough that it probably needs some introduction: it is the study of the timekeeping processes and rhythms of biological systems, from humans to plants and animals. While for many of us this term likely sounds intimidatingly technical, we might be more familiar with phrases like "body clock" or "circadian rhythms." In this volume (and in his broader three volume series), Shackleford aims to deliver the first "systematic academic history of chronobiology" (p. 6). The terms "systematic" and "academic" are central to Shackleford's project, in many ways a historical "myth-busting" endeavor, righting (or at least clarifying) the patchy and dogmatic history of the discipline, which has so far been written by its leading scientists in the twentieth century. Chronobiology seems to have suffered more than most at the hands of its scientific authors, who have deployed historical figures to construct a triumphant narrative about the development of the specialty. Using a history of ideas approach, Shackelford tracks the "incestuous" ways that scientists repeat and reinforce particular accounts of the history of chronobiology that have become canonical in popular science accounts of the subject (p. 17). Today, professional historians working in the area of rhythms studies are few and far between, although perhaps this work will encourage many more to join the fray.
In this review I will attempt to confine myself just to this installment of Shackelford's series, but it is worth pointing to the two volumes which proceed it. While the book is entirely comprehensible without having read the other two, they are certainly worth flagging for the historian interested in chronobiology. The first volume brings the reader back to the Enlightenment to explore the early foundations of scientific interest in rhythms, particularly in the study of plants.[1] As he points out in the introduction to the first volume, Shackelford is specifically interested in scientific inquiry that relates to rhythms as being endogenous to the body and not, for example, in astrology or the concept of microcosm-macrocosm. In the second volume, Shackleford moves into the eighteenth, nineteenth, and early twentieth centuries as scientists and physicians become interested in the rhythmic nature of animal, insect, and human bodies.[2] This is a crucial area of the history of rhythms (particularly ecological work with marine animals) that is almost always skipped over in existing histories and tackled expertly by Shackleford. In this final volume, we move to the heart of matter as we enter the twentieth century and the contemporary discipline of chronobiology emerges. It is the period in chronobiology history which is most familiar to those of us with a preexisting interest in the subject matter (i.e. the seminal Cold Spring Harbor Symposium on Biological Clocks in 1960) and yet, as Shackleford shows, it is one that is desperately in need of critical attention.
The Search for Biological Clocks: Metaphors, Models and Mechanisms takes as its central subject the twentieth-century search for the clock within biological systems. It "trace[s] the chief ways in which chronobiologists modeled biological rhythms, how they imagined rhythmic behaviors to be generated and controlled in organisms, and their search for specific biological mechanisms" (p. 28). The subject matter is sweeping, moving across time and place and introducing the reader to the enormous and multidisciplinary network of researchers interested in the hunt for biological timekeeping mechanisms—from scientists studying tidal crabs to physicians interested in pulmonary rhythms. Shackleford homes in on the key debate that sat at the center of rhythms research in this period: Are the repeated rhythms of bodies the result of external (exogenous) forces or internal (endogenous) ones? Shackleford demonstrates how the dominance of particular figures in the scientific field like Colin Pittendrigh, Jürgen Achoff, and their acolytes has had a marked and at times warped effect on its historical memory. For example, Shackelford shows that while Pittendrigh claimed that he was the first to acknowledge the importance of temperature independence in the study of rhythms, this was actually an issue that had been occupying scientists at least several decades previously (see chapter 2). He resurrects the overlooked figure of Frank A. Brown Jr.—often depicted in histories of chronobiology as "an incorrigible crank" (p. 30)—who was an outspoken advocate for rhythms as exogenous (environmental) and whose work remained an important and driving force within the scientific community for much longer than acknowledged in most scientific histories.
The book focuses in on the search for the biological clock, taking its departure in the key question, Why were scientists looking for a clock in the first place? "The search for clocks presupposed an expectation that they exist" (p. 24) and that a "clock" is a suitable metaphor for a biological function. As Shackelford prompts the reader, "To what extent does the operation of a clock, an inorganic machine, resemble organic function?" (p. 28). Was it even possible for scientists to locate "the biochemical and organic structural equivalents of gears, escapements, and springs?" (p. 29). The core thread of the volume tracks this shift from metaphor in the early twentieth century to the discovery of mechanisms (and models capable of revealing them) by midcentury. As Shackelford masterfully demonstrates, such a presumption colored a large part of the research being done in the twentieth century to locate the clock. For if there is not such a thing as a body clock, then it demanded a look outward to an unknown cosmic "Faktor X"—a branch of research that received little if no serious historical attention, in large part due to its characterization in histories written by scientists (or "the victors," as Shackelford calls them, p. 30). This assumption that rhythms can be understood as "clockwork" also spoke to a philosophical debate into the nature of life itself: Are living things static or rhythmic? The clock metaphor is inherently mechanistic, so it is not surprising that many of its models came from chemistry and electronics (see chapter 3). It was not until the "molecular biological turn" (p. 213) and the development of new methodologies like genetic knockouts and DNA splicing that scientists actually had the tools to examine the biological mechanisms that govern circadian rhythms (see chapter 6). We follow the hunt for the clock from particular hormones to organs, tissues, cells, and finally, DNA with the discovery of clock genes in the 1970s and 80s.
Shackelford dedicates his book to Franz Halberg (1919-2013), a leading chronobiologist who was in fact the one to encourage him to pursue this research subject. Drawing this connection to Halberg is fitting because the sources of information about chronobiology rely on the professional writings and oral histories of a few key scientific figures in the twentieth century. To undertake his analysis, Shackelford draws primarily on published scientific accounts and scientific articles related to rhythms across different fields of science, medicine, and even engineering. Of course, working with these kinds of sources means some of the more social and cultural aspects of the discussions are obscured. But, as Shackelford points out, chronobiology is both a very new specialism of biology, and sadly, many of its key figures failed to leave behind much in the way of archives (p. 12). An essential feature of the work is Shackleford's incorporation of German-language sources into his analysis. The vast majority of leading rhythms researchers in the twentieth century were of German extraction, working in German universities, or publishing in German—likely a crucial reason why the history of chronobiology itself has remained marginal in the history of science due to the generally poor language skills of English-speaking historians (me included). Most of the current historical work on the history of chronobiology is currently being done in German universities—for example, the work of Hannah Ahlheim.[3] Shackleford's analysis of key German-language publications makes the book a crucial resource for historians and students interested in working in the subject.
As Shackleford himself readily admits, the book is highly technical and in places decipherable only by specialists with a preexisting knowledge of chronobiology or at least some grounding in physiology and the life sciences (p. 46). While rendering the book not the most approachable for a general reader (chapters 6 and 7 are especially eye-watering), this detail is also a testament to the author's ability to immerse himself in the science and its methods. At times, Shackleford allows himself to become lost in detail, leaving the work feeling less like a general introduction to the history of scientific discipline than a highly specific study of how physiological knowledge is made. While the author gestures toward some more sweeping arguments around the continued role of the vitalist versus mechanist debate in physiology or the importance of evolutionary thinking in driving chronobiology research, these bigger questions, which would tie the work more strongly into the existing historiography of the life sciences, are occasionally lost in a sea of detail. In fairness to the author, these big-picture arguments are more apparent if the series is read as a whole. Shackelford also notes in his introduction to the volume that he has not taken the time to tackle the gender or material dimensions of the analysis (p. 21). While we do not all need to be historians of gender, there are moments when this element would have benefited from at least some attention.
The Search for Biological Clocks: Metaphors, Models and Mechanisms is thoughtful, complex, and at times overwhelming in its technical detail. Shackelford has delved into an enormous corpus of scientific material and paves a path through the largely untrodden territory that is the history of chronobiology. I am not quite sure if he achieves his goal of creating a "cogent narrative" of the field, but as a first foray into a tricky subject, the book certainly creates the first "map" of the topic (p. 7). For a historian interested in rhythms, it provides a wealth of insights and future directions for research, including key figures, seminal moments, and central texts. For those outside this particular area of study, the utility of the volume might be more obscure. But with a little bit of reflection, it contains much of interest to historians and philosophers of medicine, science, technology, and environment. The technical detail of sometimes bizarre chronobiological experiments is fascinating to those interested in the material culture and methods of twentieth-century science—Janet Harker's Frankenstein-like "paraboisis" (surgical joining) of cockroach bodies, for example, used as an argument that the "body clock" was hormonal (pp. 59-62). Or the enterprising methods developed by Seymour Benzer and Ronald Konopka to study clock genetics in drosophila before the ability to clone and sequence genes (pp. 271-76). Data and mathematics are a central piece of the story, as finding mechanisms of accurately measuring rhythmicity in data was a key challenge for twentieth-century rhythms researchers (see chapter 1's discussion of the Phase Response Curve). The volume (and indeed the series) deals in great part with the history of ecology and marine biology, given the importance of tidal rhythms in the history of rhythmicity overall—an excellent resource for environmental historians. The account in chapter 7 of the discovery of clock genes tracks an essential story in the history of late twentieth-century molecular biology.[4] Most importantly, with this work Shackelford establishes himself as the preeminent expert on the history of chronobiology, a field which this publication will hopefully encourage to expand even further.
Notes
[1]. Jole Shackelford, An Introduction to the History of Chronobiology, Volume 1: Biological Rhythms Emerge as a Subject of Scientific Research (Pittsburgh: University of Pittsburgh Press, 2022).
[2]. Jole Shackelford, An Introduction to the History of Chronobiology, Volume 2: Biological Rhythms in Animals and Humans (Pittsburgh: University of Pittsburgh Press, 2022).
[3]. Hannah Ahlheim and Jonathan Holst, “Masters of Time: Chrono-Biologizing Sleep in the 20th Century,” Historical Social Research 48, no. 2 (2023): 63-90; Hannah Ahlheim, Der Traum vom Schlaf im 20. Jahrhundert: Wissen, Optimierungsphantasien und Widerständigkeit (Göttingen: Göttingen University Press, 2018), and "The Measurement of Sleep and the Optimization of Humans: A German-American History (1930–1960)," Zeithistorische Forschungen 10, no. 1 (2013): 13-37.
[4] See also Jonathan Weiner, Time, Love, Memory: A Great Biologist and His Quest for the Origins of Behavior (New York: Vintage Books, 2000).
Citation: Kristin Hussey. Review of Shackelford, Jole. An Introduction to the History of Chronobiology, Vol. 3, The Search for Biological Clocks: Metaphors, Models, and Mechanisms. H-Environment, H-Net Reviews. July, 2024.