Haeckel’s Embryos Haeckel’s Embryos { I M A G E S , E V O L U T I O N , A N D F R A U D N I C K H O P W O O D The University of Chicago Press Chicago and London Published with the support of the Getty Foundation } The University of Chicago Press, Chicago 60637 The University of Chicago Press, Ltd., London © 2015 by The University of Chicago All rights reserved. Published 2015. Printed in China 24 23 22 21 20 19 18 17 16 15 1 2 3 4 5 ISBN-13: 978-0-226-04694-5 (cloth) ISBN-13: 978-0-226-04713-3 (e-book) DOI: 10.7208/chicago/9780226047133.001.0001 Library of Congress Cataloging-in-Publication Data Hopwood, Nick, author. Haeckel’s embryos : images, evolution, and fraud / Nick Hopwood. pages cm Includes bibliographical references and index. ISBN 978-0-226-04694-5 (cloth : alk. paper) — ISBN 978-0-226-04713-3 (e-book) 1. Haeckel, Ernst, 1834–1919. 2. Evolution (Biology)—History. 3. Scientific illustration—History. 4. Embryos. I. Title. QH361.H67 2014 576.8—dc23 2014016887 ∞ This paper meets the requirements of ANSI/NISO Z39.48–1992 (Permanence of Paper). NICK HOPWOOD is reader in history of science and medicine in the Department of History and Philosophy of Science at the University of Cambridge. He is the author of Embryos in Wax , coeditor of Models: The Third Dimension of Science , and cocurator of the online exhibition Making Visible Embryos For my parents, David and Joyce vii CON T E N T S 1 Icons of Knowledge 1 2 Two Small Embryos in Spirits of Wine 9 3 Like Flies on the Parlor Ceiling 31 4 Drawing and Darwinism 53 5 Illustrating the Magic Word 69 6 Professors and Progress 89 7 Visual Strategies 107 8 Schematics, Forgery, and the So-Called Educated 127 9 Imperial Grids 145 10 Setting Standards 171 11 Forbidden Fruit 189 12 Creative Copying 201 13 Trials and Tributes 217 14 Scandal for the People 229 15 A Hundred Haeckels 249 16 The Textbook Illustration 263 17 Iconoclasm 281 18 The Shock of the Copy 297 Acknowledgments 303 Abbreviations 307 Notes 309 Reference List 339 Index 373 Fig. 1.1 Early vertebrate embryos, credited to a secondary source from 1901, in Scott Gilbert’s developmental biology textbook, alongside photomicrographs and more recent diagrams. Gilbert 1997, 254–55, by permission of Sinauer Associates. 1 Icons of Knowledge { 1 } At the end of the twentieth century the leading textbook of developmental bi- ology reproduced a figure first published over a hundred years before (fig. 1.1). With columns for species and rows for stages, the grid shows embryos of hu- mans and other backboned animals beginning almost identical and diverging toward their adult forms. Images like this debuted in 1868 in the first accessible Darwinist system, an anticlerical gospel of progress by the combative German evolutionist Ernst Haeckel. For the first eight weeks of development, he roared, you cannot tell even an aristocrat from a dog. The church denied these pictures as “diabolical inventions of materialism,” he said, yet that only testified to their power as evidence of common descent. 1 Schools initially banned Haeckel’s books, but children sneaked them to read “with burning eyes and soul.” 2 In the early 1900s his embryos entered American classrooms and were eventually repro- duced worldwide. As the most influential illustration of the relations between evolution and development, they are still a reference point for research. Old images shape current views. Look through websites, books, and TV pro- grams, the main vehicles for communicating knowledge today. Among the flood of new pictures, copies represent a select few from the distant past. Their contem- poraries fell by the wayside long ago, but the survivors have lasted for decades. Some are celebrities. The 1895 X-ray of Bertha Roentgen’s “hand with rings” is hailed as a “photograph that changed the world,” the atomic mushroom cloud held up as a “cultural icon” that encapsulates an era. 3 Since the 1960s the Apollo snapshots of Earth from space have portrayed the planet for environmentalists and advertisers. Antiabortionists and sex educators exploited Lennart Nilsson’s fetal photographs from around the same time. 4 Such icons have exceptional reach and symbolic power, but far more images have played influential roles. C H A P T E R O N E 2 They have been textbook illustrations for students to learn or technical standards that define what re- searchers and practitioners see and hence know. 5 Map projections determine the apparent size and status of countries. 6 Anatomical atlases guide diagnosis, sur- gery, and expectations of body shape. 7 They channel attention in certain directions and close off others. How do images become standard, canonical, clas- sic, even iconic? Art historians debate what sanctified the Mona Lisa as the most famous masterpiece in the world. It was among the paintings selected to found the Louvre after the French Revolution, but was not the most celebrated in that group. Only the nine- teenth-century making of the Leonardo cult and of the femme fatale , followed by the theft of the work in 1911, raised it to the highest level of fame. 8 The DNA double helix benefited from aesthetic appeal and its status as “the secret of life,” but was not an instant hit in 1953. Stardom came with recognition of the discovery, and the opportunities the structure offered designers to embody hope, hype, and fear as molecular biology took off. 9 Intrinsic qualities count, but users decide which images will make a splash and then sink with- out trace, while others achieve their greatest influence years or even centuries later. Taking the visual dimensions seriously has en- larged and revised our histories of knowledge. 10 It has discovered the importance of nonverbal communica- tion and of competition between different approaches to producing and using images. The emphasis has been on the more obvious novelties, but research has begun to illuminate the everyday routines of use. We can learn more about these and become sensitive to more subtle innovations by paying closer attention to long-term trajectories. The fate of a picture is sealed by whether and how it is reused. The pressures of didac- tic efficacy and accommodating data, of cost and aes- thetics, of propriety and politics, of technique and the law converge on copying. 11 This is usually dismissed as derivative, but all successful images have stories of copying to tell. 12 Histories include much-copied illustrations—and so help make them classic—but tend to miss their full significance by acknowledging their first appearances only. By contrast, investigations of afterlives show that consumption can matter as much as production and copying as much as design. 13 Stephen Jay Gould put the issue on the agenda by highlighting the power of icons that authors and publishers recycled through one text- book after another (fig. 1.2). He targeted primate series and trees that made evolution and progress look as though they marched hand in hand. 14 More recently, David Kaiser demonstrated in compelling detail how postwar physicists adopted Feynman diagrams, and stayed loyal through theory change, while seemingly more suitable alternatives failed to catch on. 15 But most studies of standard images remain sketches or Fig. 1.2 A montage of Darwin icons on the cover of a biography published in the wake of the 1959 centennial celebrations, part of the Darwin revival following the modern evolutionary synthesis. The dog embryo had already been much reproduced, including by Haeckel, when it featured in The Descent of Man (here fig. 6.9). Design by Ellen Raskin reproduced from de Beer 1965 by permission of MM Literary Partners. I C O N S O F K N O W L E D G E 3 cameos; we need to paint on a larger canvas to realize the potential of the approach. Keeping the spotlight on a single set of images, over the long term and as they addressed various users and viewers, brings out continuities and offers fresh perspectives on change. 16 It can also provide counter- points to those tales of triumph that only ever go from strength to strength. Critiques accompany even the most dominant images, and different people, in differ- ent places or at different times, have rejected some of the most successful outright. 17 Success encompasses not just fame, but being taken for granted and becom- ing notorious too. Controversy is often part of the story and, by pushing participants to articulate their assumptions, helpfully makes decisions explicit. To find out how pictures of knowledge succeed and fail, become accepted and cause trouble, this book fo- cuses on Haeckel’s embryos: textbook classic, icon of evolution—and the most fought-over images in the history of science. They have been so disputed because allegations of forgery—the most extreme threat to the integrity of an image and its maker—are almost as old as the pictures themselves. Within months of publica- tion in 1868 colleagues accused Haeckel of playing fast and loose with the evidence for common descent. Six years later he aligned the most important battle in the history of embryology with modern Germany’s prin- cipal confrontation between church and state, and charges of forgery grew legs. In that heyday of lithog- raphy and wood engraving for the middle class, critics pointed to several misdemeanors, including creating false identities by having the same blocks printed three times to represent three different species. This sharp practice was swiftly corrected and slowly admitted. They also said Haeckel had schematized tendentiously from well-known originals. These accusations, leveled at the comparative grids that are the subject of this book, were and remain more debatable. Religious and political enemies reworked the charges on a larger scale in 1908–10, when Haeckel was Germany’s most famous and notorious scientist, the world’s greatest living evolutionist, and the best- known scientist-artist of the age (fig. 1.3). The first mass audience now followed the struggle over illustra- tions printed in photo relief. By 1914 the drawings had been denounced, though also defended, in hundreds, if not thousands, of magazine and newspaper articles. They were nevertheless copied into high-school and college textbooks and so survived to become some of the most widely seen embryo images of all time. But in 1997 an embryologist denied that vertebrates ever look so similar and, in ignorance of the earlier critiques, charged Haeckel with fraud. “Generations of biology students may have been misled,” reported Science magazine. 18 Seizing the opportunity, the neo- creationist campaign for so-called intelligent design forced publishers to take the figures out. Drawings from the German Empire had become lightning rods for online controversy at the beginning of the twenty- first century. Fig. 1.3 One of the postcards sold in Haeckel’s hometown shows him painting watercolors in 1914. Though the Darwinist was frequently photographed with ape skeletons, many old- age portraits depict the visionary drawing, sketching, or painting nature (see also fig. 15.2). Sometimes he is immersed, as in these botanical landscapes; more often he looks up to reveal the fire still burning in his eyes. Post- card by Alfred Bischoff (Jena) stuck into the author’s copy of the “physiognomical study” Haeckel’s son edited for his eightieth birthday: W. Haeckel 1914. C H A P T E R O N E 4 Haeckel’s embryos are exceptional, because over such a long period they have played so many of the different roles that images can play. That makes them broadly relevant. By reconstructing each significant process of production and reproduction, use and de- bate, this book tracks the triumphs and tribulations of one image that engaged specialists, teachers, students, and lay publics through massive transformations in the sciences and the communications industry. It thus offers histories that should shed light on other cases. To keep this feasible, I concentrate on the main sites of innovation and discussion, German-speaking Europe and then also Britain and especially the United States as it overtook Germany as the center of world science. Over two centuries, from the conditions that made the pictures possible to arguments about the rights and wrongs, I offer what I believe is the most comprehen- sive history of a scientific image. This will show how copying, the epitome of the unoriginal, has been cre- ative, contested, and consequential. A few historians were already familiar with parts of the story behind Haeckel’s embryos when the news broke in 1997. I had come across them in textbooks at school and university, and then as a graduate student and postdoctoral fellow in developmental biology. Having retrained in history of science and medicine, I worked on German Darwinism and was starting a project on visualizing embryos, so knew enough to dis- miss the fuss as old hat. 19 Then it dawned on me that the repetition, of the pictures and the charges, was the most exciting aspect of the whole affair. How could some of the most disputed images have been copied as textbook figures? And how, if they were so standard, could they have sparked three major controversies and countless small-scale debates? Trying to answer these questions made me realize how little I really knew, and how little the history of science could then say, not only about icons, but also about embryos—and how much these pictures might help. If doing justice to images changes the histories around them, tackling such challenging illustrations promised to transform understanding of embryology and of evolutionism. The plates started in Haeckel’s Natürliche Schöp- fungsgeschichte , which went through a dozen editions and as many translations, including into English as The History of Creation . The most successful variant featured in another title that shaped the visual lan- guage of Darwinism, his more embryo-focused An- thropogenie , which managed two English translations as The Evolution of Man . When historians are only be- ginning to examine the finest embryological plates, 20 it might seem perverse to devote a whole book to dubi- ous diagrams that Haeckel knocked off in a few hours for works that specialists have always given a bad press. Compared, however, with general-interest pamphlets and magazines, these tomes of five hundred to a thou- sand pages may appear too complex for many nonsci- entists to have read. 21 In fact, as prominent illustra- tions in the foremost syntheses, his grids could not have been more strategically placed. 22 They impressed and provoked pupils and teachers, the hacks who wrote the genuine bestsellers and the anatomists who tightened standards in response. Having mediated between popular science, academic investigations, classroom teaching, and media reports, Haeckel’s drawings point the way from an intellectual history of embryologists to a social history of embryos still alert to the disciplinary politics of knowledge. 23 They give extraordinary access to the anatomical, graphic, and publishing practices that made development a process we can see. Images of development, particularly of develop- ing humans, are so familiar it is hard to believe that just 250 years ago they were almost nowhere to be found. 24 Only in the nineteenth century did develop- mental series picturing progressively more advanced stages become the dominant representations of the origins of human and animal life. Seeing development depended ultimately on encounters through which practitioners collected material—via hunters, breed- ers, and explorers from assorted animals, and via physicians from women patients—and reinterpreted it in embryological terms. Scientists and artists then derived vivid images which, with some difficulty, they selected and ordered into series. These were prepared for publication and distribution, with frequent inter- play between research, teaching, and display to the lay audiences who eventually admitted embryos into their worlds. The series stood for the course of a preg- nancy. Through Haeckel’s dictum, “ontogeny recapit- ulates phylogeny”—we climb our evolutionary tree in the womb—they also represented the history of life on earth. Recent images of embryos and fetuses have been hotly disputed in struggles over reproduction. Controversy is not new, even in relation to abortion, 25 I C O N S O F K N O W L E D G E 5 but evolution once provided the main visual frame. The “first public embryo spectacle” 26 starred Haeckel’s illustrations, which entered ordinary homes and stim- ulated influential research. The clash between Haeckel and his chief critic, Wil- helm His, did not just pit phylogeny against physiol- ogy, and so define the options for embryology through the twentieth century. Professor His also founded the lines of research, little-studied by historians, that in- vested most in visualizing especially human devel- opment. Haeckel’s pictures goaded His and others to produce the normal plates and stages that serve as the standards by which biologists divide embryogenesis today. 27 The grids survived in their own right as well, to become standard in the sense of much used, and so shaped the recent debate in evolutionary developmen- tal biology over the existence of a stage when all verte- brates look the same. We should resist the false choice between His’s fine lithographs and Haeckel’s dodgy diagrams. They need to be seen together. Haeckel’s Embryos thematizes the copying of the pictures and the repetition of the forgery charges, and the ways these did or did not intersect. On the one hand, it places the physical genesis and reproduction of the pictures in a history of copying, at times biased or creative, at others as faithful as anyone could desire or as derivative as can be. Copying was at issue as soon as a detractor said Haeckel had distorted already-stan- dard illustrations. Since then, the individual figures on his plates have often been compared with their pre- sumed sources. Paying attention to arrangements on pages and in books will divulge more. The biggest in- novation was the invention of the grid, an aid to com- parative seeing like the pairs, tableaus, series, arrays, and overlays which helped eyes detect similarities and differences, and so distinguish patterns (fig. 1.4). 28 Pre- Fig. 1.4 “Development According to Darwin’s The- ory” in the Fliegende Blätter , the Bavarian Punch In the progressive evolution of social types from everyday objects, additional humor comes from the simultaneous development, for example, of the lady from a coffee pot, her parasol from a carefully placed spoon, and her dog from a pair of balls. Four pseudoevolutionary series are aligned in a com- parative array, as if to highlight the profusion, by the 1870s, of both evolutionary series and spoofs thereof (for example, fig. 5.1). “Entwickelungen nach Darwin’s Theorie,” a full-page wood engraving from Fliegende Blätter 56 (1872): 160. Niedersäch- sische Staats- und Universitätsbibliothek Göttingen (NSUB). C H A P T E R O N E 6 viously unexploited manuscripts, including the origi- nal drawings that had lain hidden since 1868, 29 let me reconstruct each step. Even today, images may go only where networks run, databases have been set up, and permission given. In the nineteenth and twentieth centuries, when new methods facilitated copying for large audiences, tech- nical difficulties and social hierarchies more obvi- ously shaped content and distribution. The paradoxes of Haeckel’s embryos highlight constraints and also choices. Why did most early copies pick out cells, col- umns, or rows, rather than reproducing the charac- teristic grid? How could the illustrations be present in schoolbooks adopted in the state of Tennessee in the aftermath of the 1925 trial of John Scopes for teaching human evolution, but absent from German and Brit- ish texts published at the same time? Why, conversely, did almost no book dedicated to embryology copy the figures until as late as 1983? That certain groups repu- diated them in certain places at certain times pushes us to explain how they could have been so warmly embraced or blithely taken for granted by others and elsewhere. On the other hand, this book tracks the claims made with Haeckel’s pictures and about them, es- pecially the accusations of fraud. Alleging forgery in science is not just to distrust an individual, but to question the standards of a field. Yet fraud busting calls for systemic reform have tended to present as iso- lated rogues the historical scientists who have been ac- cused. 30 As a big, polarizing figure Haeckel has invited this individualist, villains-and-heroes approach: was he “the scientific origins of National Socialism,” as an American historian had it, or the “pioneer of scientific truth” lauded by the architect of East German Stalin- ism? 31 Most accounts use, and more often misuse, a tiny fraction of the available sources to try and retry him again and again. Influential recent interventions have juxtaposed drawings from 1874 with late twen- tieth-century photographs containing knowledge he could not have had. 32 More serious assessments have compared his illustrations with their supposed models and either picked on discrepancies to find him guilty or deployed arguments, such as the pedagogical value of schematics and the theory-ladenness of all effective drawings, to contextualize and so excuse his actions. 33 Recently, he has been placed within a code of represen- tation oriented toward truth, which permitted some manipulation, at odds with a new ideal of “mechanical objectivity.” 34 Each interpretation captures something import- ant, but all are too general to explain why these par- ticular pictures became controversial, and all are too focused on Haeckel to account for their fates in others’ hands. Even a trial would have to consider the oppo- nents’ agendas and the negotiations that defined what would count as fraud. In a short but detailed and care- ful dissertation of 1981, Reinhard Gursch concluded that trouble came less from the images than from enemies’ attempts to destroy Haeckel’s credibility. The historian of biology Jan Sapp suggested, more radically, that since controversies serve to confirm or refute attributions of fraud, the verdict depended on biologists’ overall assessment of Haeckel. 35 This risks underestimating the part played by his provocative be- havior, but rightly shifts attention to the fight for his reputation that began in Germany and reverberated worldwide. 36 Because Haeckel was accused early and often, the allegations have played a larger biographical role than those, long after the events, against Gregor Men- del, the “father of genetics,” and Robert Millikan, the physicist who determined the charge on the electron. 37 They are a rich seam of commentary on the foibles of the Romantic genius and on scientists’ morals. 38 But the link between maker and image often broke: debates over Haeckel the artist lost sight of specific pictures, and these flourished in part because they stopped being credited to him. Images are also no mere vehicles for ideas. Nothing would mislead more in this case than to assume that reproduction followed acquiescence in the doctrine of recapitulation. Use did not even always correlate with acceptance as accurate representations. In an irony of iconoclasm, Haeckel’s figures were never more available, thanks to creation- ists and the Internet, than when most rejected as fakes. Darwinism is no longer really at stake, and recent research on embryos demonstrates evolution better than Haeckel ever could. 39 Nor can history bridge the ideological chasm between creationism and main- stream biology across which the latest battle has been fought. It does seek to understand and explain actions on all sides as it recovers evidence that every- one should take into account. The adventures of this extraordinary icon more importantly direct attention to the ways scientific images become contested and I C O N S O F K N O W L E D G E 7 canonical, rejected and reproduced. They should help show why, when we open a textbook, turn on a science program, or visit a web page, we see certain illustra- tions and those alone. Haeckel’s Embryos proceeds roughly chronologically, but only roughly, because each short chapter develops a distinct theme, and some chapters cover different themes for the same periods. The pace changes ac- cording to the timescales on which the story unfolded. Some chapters linger to analyze the production of the primary images, explore local responses, or piece together month by month how the forgery charges caught fire. Others take a bird’s-eye view to survey pat- terns of copying or accusation over many decades and between countries. To make the most of the pictures and charges as probes, the book also moves in toward and out from the main events, as it investigates medi- cal teaching and conflicts over materialism, “imperial embryology,” and the reactions of lay readers. Most illustrations in the present work have never appeared beyond their original contexts before, though many were copies even there. They are of Hae- ckel’s pictures, those he used, and those that repro- duced, opposed, or spoofed his own. They put these icons back among their contemporaries and in various settings of production and viewing. The captions alert viewers to significant features and to huge differences of format and accessibility. The figures thus comple- ment the text by sharing evidence and a sense of the research materials. They suggest connections and point to larger visual worlds. The next three chapters (2–4) review the condi- tions of possibility of the pictures by introducing how developmental series came to be produced, how stu- dents and wider audiences were exposed to embryos, and how Haeckel became an artistic Darwinist. Four chapters (5–8) reconstruct the making of the illustra- tions in Schöpfungsgeschichte and Anthropogenie , and the debate, from the initial complaint to the first peak of controversy. Then five chapters (9–13), all moving from the 1870s to the early 1900s, explore his expan- sion of the grid through editions and translations, specialists’ visual standards, nonscientists’ encounters with these “forbidden fruits,” copying into other evo- lutionary works, and the revival of the charges when Haeckel became an international celebrity. The last chapters tackle the “scandal for the people” of 1909, its effects on his twentieth-century reputation, copying into textbooks, and the paradoxes of iconoclasm since 1997. Chapter 2, about how embryologists made the serial images from which Haeckel would learn, opens with a story about a pair of embryos in a jar. 9 Two Small Embryos in Spirits of Wine { 2 } In the most famous embryological anecdote, the most distinguished practitioner admitted that he did not label a bottle and could not identify the specimens in- side. In 1828, in a book so celebrated in the history of biology that its only nine- teenth-century rival is the Origin of Species , the Estonian nobleman and Prussian professor Karl Ernst von Baer put sloppy labeling to good use. I possess two small embryos in spirits of wine, for which I neglected to note the names, and I am now quite unable to determine the class to which they belong. They could be lizards, small birds, or very young mammals. Head and trunk formation is so similar in these animals. Those embryos still lack extremities, but even if they were there, in the earliest stage of development it would teach us nothing, since the feet of lizards and mammals, the wings and feet of birds, and the hands and feet of humans develop from the same basic form. Thus the further we go back in the developmental history of the vertebrates, the more similar we find the embryos as wholes and in the individual parts. 1 Charles Darwin reworked the story, while attributing it to someone else. 2 Haeckel deployed it as evidence from the highest authority that he had not drawn figures too alike, and his recent defenders have followed suit. 3 But critics around 1900, priding themselves on progress since Baer, poked fun at Haeckel’s inability to distinguish classes as incompetence at best. “ Mix up all kinds of embryos in a pot ,” an anatomist boasted, “ and I will tell you the origin of every one .” 4 Baer’s tale epitomizes the work on which Haeckel would build. Baer prob- ably reviewed mental images, though he could also have consulted his own drawings or the few illustrations then available in books, as he tried to interpret C H A P T E R T W O 10 those specimens in relation to series of stages through development. Comparing series, a key operation of knowledge making, was central to the sciences of or- ganic form. It linked fossils, adults, and embryos, or the history of life on earth, the classification of the animal kingdom, and the development of the mani- fold groups. Did these combine into a single series or several? Did the series run in parallel or diverge? Did all vertebrates, even all animals, ever really look the same? Histories of biology revel in these big questions about the shape of life, but tend to slip their moorings and float loose in an ethereal realm of ideas. 5 Baer’s story grounds the high theory in the encounters with collections and images that constructed the develop- mental series on which comparative judgment could go to work. Development is easily taken for granted now that schoolbooks, advice manuals, films, and the web offer elaborate sequences of progressively more ad- vanced embryos and fetuses. Baer and Haeckel, by contrast, experienced developmental series as recent achievements and still a major challenge. Embryology was harder than adult anatomy because each animal needed not just one stage, but several, and these im- mature forms were tougher to find. Making series—by collecting, drawing, selecting, and ordering embryos in sequence for publication and debate—took up most of researchers’ time. 6 So while they gave theory, even speculation, its due, they credited careful observation from nature for recent progress in the science. 7 They also knew how often the difficulty of obtaining com- parable series brought soaring theoretical ambitions down to earth. Developmental Series Contrary to popular belief, eighteenth-century natu- ral historians mostly did not arrange collections ac- cording to the great chain of being, an ascending se- quence from the rocks below ground through plants and animals to humans and even angels above (fig. 2.1). Trees and other shapes figure too, while botani- cal gardens were laid out like maps. 8 Yet around 1800 scales did turn into ladders, and inventories into the results of development. Series came to express nei- ther mere chronology nor endless cycles, but history and progress, the biggest story of nineteenth-century science. In hospitals as in art galleries, curators and Fig. 2.1 The great chain of being. The Genevan naturalist Charles Bonnet posited an infinitely graded and all-encompassing chain that appeared only imperfectly to human understanding. In this header to his book on the contemplation of nature, the clouds have cleared to reveal a few representatives of the middle part, while the upper and lower reaches stay obscured. Engraving by Frederik Ludvig Bradt from Bonnet 1781, 1, by permission of the Syndics of Cambridge University Library. T W O S M A L L E M B R Y O S I N S P I R I T S O F W I N E 11 professors placed collections in sequence to show the history of painting and the course of a disease. Books and, increasingly, journal articles displayed serial il- lustrations on the page. But as attention shifted from the external surfaces and visible characteristics of nat- ural history to the internal organization and functions of comparative anatomy, leading naturalists split even the animal series. We feel the weight and length of the chain in their repeated efforts to break it up. 9 Change was under way before the French Revolu- tion of 1789, but with the eyes of the world on Paris, the reformed Museum of Natural History showed the path to the future. Writing two generations later, Hae- ckel celebrated one curator, Jean-Baptiste Lamarck, for pioneering evolutionism. Renovated versions of La- marck’s transformist ideas were popular in the 1820s, but his own speculative “zoological philosophy” had confined the earth and its inhabitants in a steady state of flux without real change. Haeckel praised a younger curator, Georges Cuvier, for having demonstrated the fact of extinction, thus establishing the otherness of “the former world” and giving the earth a true his- tory. 10 But Haeckel regretted that Cuvier had posited the creation of fixed species after each of a series of catastrophes, and that his huge authority had ensured the long dominance of these ideas. Cuvier powerfully divided the animal kingdom too. Refining the classification of Carl Linnaeus, which was convenient but “artificial” because based on single characters, he sought a more “natural” system. For Cu- vier, structures depended on the functions demanded by different environments and could be understood only as organized wholes. The other parts were subor- dinated to the functionally most important elements, ultimately the nervous system. This justified theatri- cal reconstructions of entire extinct forms from single teeth or bones. Cuvier in this way distinguished four separate plans of organization, or embranchements . Re- interpreting the old distinction between animals with and without backbones, he placed the vertebrates on a par with three other divisions: articulates (largely arthropods and annelids), radiates (echinoderms and other groups), and molluscs. 11 Embryology lacked institutional recognition and had little room in Cuvier’s system, but offered a paradigm of progressive development from simple to complex that became influential elsewhere. The new science drew on three main areas of eighteenth- century knowledge. Anatomists and zoologists turned natural histories of monsters into teratology, a spe- cialty devoted to malformations, which elucidated once-threatening anomalies as lawlike excesses, defi- ciencies, or arrests of development. As male surgeons muscled in on midwifery, interest in the pregnant uterus fed the making of human embryology. Above all, anatomists and physiologists reworked investiga- tions into generation. 12 While mechanical philosophers struggled with embryos, two groups of theories had aimed, with some difficulty, to account for the origin of organized beings. Epigenesis , the ancient view named by William Harvey in 1651, taught that organization arises pro- gressively from unorganized matter. Its rival, preexis- tence , countered that, all appearances to the contrary, adult structures preexist, or are preformed, waiting to unfold. Most saw the egg as the site of preformation; a few favored the “animalcules” in the male semen. En- lightenment epigenesis reeked of materialism, while preexistence was orthodox in positing a passive nature determined by divine laws. But if an omnipotent and benevolent God had made all germs at the Creation, why were there monsters, and how could a polyp re- generate from its parts? Though additional assump- tions explained these problems away, they contributed around 1800 to a victory for epigenesis—but epigene- sis of a new kind. 13 The medical dissertation that Caspar Friedrich Wolff wrote in Halle in 1759 had argued for epigene- sis, but created order by a vital force. The Göttingen professor Johann Friedrich Blumenbach taught from 1790, with philosophical legitimation from Immanuel Kant, that rather than trying to explain the origin of organization mechanically, researchers must accept this fundamental feature of living things as given. That put questions about origins and the nature of the vital forces safely off-limits, but opened up a vast field within which to explore the relations of the plans of organization and discover the laws by which living animals, fossils, and embryos were not “developed” by God or some force, but developed themselves. In the German lands—the patchwork of princely states that were loosely held together in the Holy Roman Empire until this collapsed like a brittle husk when Napoleon defeated Prussia at the Battle of Jena in 1806—forma- tion was the best guide to form. Studying embryos promised to show dynamically how stem forms had