The Politics of Sources Meets the Practices of the Librarian: An Interview with Esther Chen.

[I] want to single out one phenomenon that could be called the 'politics of sources'. It points to the extent to which the histories that both scientists and historians can write are artifacts of the available sources. The Rockefeller Foundation not only opened its archives very early on for historical work but also invested a lot in making the archives readily available for historical exploration. During the 1980s, many young historians took advantage of this opportunity. Thus, in a relatively early phase of the professional historiography of molecular biology, one could have gained the impression that the development of the new biology as a whole was a bio-politically directed enterprise of the Rockefeller Foundation sustained by the vision that social processes could ultimately be controlled by biological processes.

Physicochemical Biology and Knowledge Transfer: The Study of the Mechanism of Photosynthesis Between the Two World Wars.

In the first decades of the twentieth century, the process of photosynthesis was still a mystery: Plant scientists were able to measure what entered and left a plant, but little was known about the intermediate biochemical and biophysical processes that took place. This state of affairs started to change between the two world wars, when a number of young scientists in Europe and the United States, all of whom identified with the methods and goals of physicochemical biology, selected photosynthesis as a topic of research. The protagonists had much in common: They had studied physics and chemistry (although not necessarily plant physiology) to a high level; they used physicochemical methods to study the basic processes of life; they believed these processes were the same, or very similar, in all life forms; and they were affiliated with institutions that fostered this kind of study. This set of cognitive, methodological, and material resources enabled these protagonists to transfer their knowledge of the concepts and techniques from microbiology and human biochemistry, for example, to the study of plant metabolism. These transfers of knowledge had a great influence on the way in which the biochemistry and biophysics of photosynthesis would be studied over the following decades. Through the use of four historical cases, this paper analyzes these knowledge transfers, as well as the investigative pathways that made them possible.

[A Botanist in the History of Paper: Open and Closed Cooperations in the Sciences Around 1900]. / Ein Botaniker in der Papiergeschichte: Offene und geschlossene Kooperationen in den Wissenschaften um 1900.

The paper uses the example of historical paper research in Vienna around 1900 in order to analyze the dynamics of scientific cooperation between the natural sciences and the humanities. It focuses on the Vienna-based plant physiologist Julius Wiesner (1838-1916), who from 1884 to 1911 studied medieval paper manuscripts under the microscope in productive cooperation with paleographers, archaeologists and orientalists (Josef Karabacek, Marc Aurel Stein, Rudolf Hoernle). The paper examines why these cooperations succeeded and how they developed over time. Here we distinguish between two forms of cooperation: while Wiesner initially worked only reactively, in a "closed cooperation", he later entered into "open cooperations", in which both parties defined research questions and methods. This form of cooperation proved particularly successful, but at the same time was especially demanding because, in addition to contributing one's own skills, it required considerable "interlocking expertise" (Andersen 2016). This was favored because the historical auxiliary sciences were in a phase of upheaval. Wiesner contributed his knowledge of technical microscopy and developed a genuine interest in historical questions, while the humanists were prepared to open themselves to scientific processes and ultimately acknowledged Wiesner as a historian of paper in his own right.

[A Cooperative and Competitive Endeavour : The Story of Germany's Early Twentieth-Century Exploration of the Antarctic]. / "Zusammenwirken" oder "Wettstreit der Nationen" : Kooperation und Konkurrenz in der deutschen Antarktisexploration um 1900.

Around 1900, one of the last major challenges in the exploration of the Earth was to map the largely untouched continent of Antarctica. Many nations participated in this endeavour, including the German Empire, which launched two expeditions before World War One: Erich von Drygalski led the first German expedition to Antarctica between 1901 and 1903 and Wilhelm Filchner led the second in 1911 through 1912. Recent literature has, for the most part, described the relationship between the expeditions of the different nations as having been focused on either cooperation or rivalry. This paper argues, however, that a strained simultaneity of international cooperation and rivalry characterized the German Antarctic expeditions. From the outset of their expeditions, the historical actors employed both modes of interaction. In their rhetoric, they referred to them as argumentative resources, and they chose their course of action following the logic of cooperation or competition, depending on the particular circumstances. The actors took pains, however, to keep a balance between the two modes of interaction in order to be able to benefit from advantages arising both from competition and cooperation. They also ensured that the rules of competition were loosely enough defined to allow them some leeway. When it came to a retrospective evaluation of the expeditions by the German public, it became clear, though, that their strategy had not been successful: neither the actors' praise for the cooperation between nations, nor the emphasis they placed on their scientific achievements was able to change the public's perception in imperial Germany that these two expeditions had been failures in the struggle to reach latitudes as southern as possible.

New perspectives in the history of twentieth-century life sciences: historical, historiographical and epistemological themes.

The history of twentieth-century life sciences is not exactly a new topic. However, in view of the increasingly rapid development of the life sciences themselves over the past decades, some of the well-established narratives are worth revisiting. Taking stock of where we stand on these issues was the aim of a conference in 2015, entitled "Perspectives for the History of Life Sciences" (Munich, Oct 30-Nov 1, 2015). The papers in this topical collection are based on work presented and discussed at and around this meeting. Just as the conference, the collection aims at exploring fields in the history of life sciences that appear understudied, sources that have been overlooked, and novel ways of engaging with this material. The papers convened in this collection may not be representative of the field as a whole; but we feel that they do indicate some elements that have received emphasis in recent years, and may become more central in the years to come, such as the history of previously neglected contexts and domains of the life sciences, the question of continuity and change on the level of practices, the history of complexity and diversity in twentieth-century life sciences and the reconsideration of the relationship between history and philosophy of life sciences.

The organism strikes back: Chlorella algae and their impact on photosynthesis research, 1920s-1960s.

Historians and philosophers of twentieth-century life sciences have demonstrated that the choice of experimental organism can profoundly influence research fields, in ways that sometimes undermined the scientists' original intentions. The present paper aims to enrich and broaden the scope of this literature by analysing the career of unicellular green algae of the genus Chlorella. They were introduced for the study of photosynthesis in 1919 by the German cell physiologist Otto H. Warburg, and they became the favourite research objects in this field up to the 1960s. The paper argues that dealing with Chlorella's high metabolic flexibility was crucial for the emergence of a new conception of photosynthesis, as a plastic, integrated system of pathways. At the same time, it led to new collaborations between physiologists and phycologists, both of whom started to re-orient their studies in ecologically informed directions. Following Chlorella's trail, hence, not only elucidates how experimental organisms forced scientists to change their conceptual approaches and techniques, but also provides insight into the interaction of different lines of research of mid-twentieth century plant sciences.

Wissenschaft im Glaubenskampf. Geschichte als Argument in den akademischen Festreden Emil DuBois-Reymonds (1818-1896).

The Religious War of Science. Historical Argumentation in the Academic Speeches of Emil DuBois-Reymond (1818-1896). Among the protagonists of the "laboratory revolution" (Cunningham/Williams) in 19th -century physiology were the self-proclaimed 'organic physicists' ("organische Physiker"), who shared a mechanistic conception of life processes. One of their key figures was the physiologist Emil DuBois-Reymond (1818-1896) who not only excelled in the field of neuroscience but also became known, over the decades of his active career, as an orator at the Berlin Academy of Sciences and Humanities. In his academic speeches, DuBois-Reymond regularly commemorated heroes of the history of science. On closer inspection, these references went far beyond paying the usual homage to precursors: This paper argues that DuBois-Reymond made use of episodes from the history of science as a means to legitimate his own reductionist research programme and, at the same time, decry idealistic natural philosophy and vitalistic positions. Drawing upon biblical rhetorics, DuBois-Reymond systematically construed experimental physiology as the culmination of a teleological development, and, hence, organic physicists as the incarnation of scientific 'redeemers'. According to him, the success of 'organic physics' displayed the peak of an inevitable development.

Discovery of causal mechanisms: Oxidative phosphorylation and the Calvin-Benson cycle.

We investigate the context of discovery of two significant achievements of twentieth century biochemistry: the chemiosmotic mechanism of oxidative phosphorylation (proposed in 1961 by Peter Mitchell) and the dark reaction of photosynthesis (elucidated from 1946 to 1954 by Melvin Calvin and Andrew A. Benson). The pursuit of these problems involved discovery strategies such as the transfer, recombination and reversal of previous causal and mechanistic knowledge in biochemistry. We study the operation and scope of these strategies by careful historical analysis, reaching a number of systematic conclusions: (1) even basic strategies can illuminate "hard cases" of scientific discovery that go far beyond simple extrapolation or analogy; (2) the causal-mechanistic approach to discovery permits a middle course between the extremes of a completely substrate-neutral and a completely domain-specific view of scientific discovery; (3) the existing literature on mechanism discovery underemphasizes the role of combinatorial approaches in defining and exploring search spaces of possible problem solutions; (4) there is a subtle interplay between a fine-grained mechanistic and a more coarse-grained causal level of analysis, and both are needed to make discovery processes intelligible.

In pursuit of formaldehyde: causally explanatory models and falsification.

Falsification no longer is the cornerstone of philosophy of science; but it still looms widely that scientists ought to drop an explanatory hypothesis in view of negative results. We shall argue that, to the contrary, negative empirical results are unable to disqualify causally explanatory hypotheses-not because of the shielding effect of auxiliary assumptions but because of the fact that the causal irrelevance of a factor cannot empirically be established. This perspective is elaborated at a case study taken from the history of plant physiology: the formaldehyde model of photosynthesis, which for about sixty years (1870s to 1930s) dominated the field-despite the fact that in these sixty years all the attempts to conclusively demonstrate even the presence of formaldehyde in plants failed.

The construction of a scientific model: Otto Warburg and the building block strategy.

In the years 1919 to 1923, Otto Warburg published four papers that were to revolutionise the field of photosynthesis. In these articles, he introduced a number of new techniques to measure the rate of photosynthesis, put forward a new model of the mechanism and added a completely new perspective to the topic by attempting to establish the process's efficiency in terms of the light quantum requirement. In this paper I trace the roots of Warburg's series of contributions to photosynthesis research by exploring three different contexts of inspiration: Warburg's own research into cell respiration, his father's work on the quantum yield of photochemical reactions in general and the photosynthesis work carried out by Richard Willstätter and Arthur Stoll. When these influences are considered together, it becomes clear that Warburg implemented a Building Block Strategy in his research: rather than inventing his photosynthesis model from scratch, he availed himself of fragments from other contexts, which he then recombined in a new and innovative way. This way of working is considered to be standard practice in scientific research.

Otto Warburg's first approach to photosynthesis.

In the field of photosynthesis research, Otto Warburg (1883-1970) is predominantly known for the role he played in the controversy that began in the late 1930s regarding the maximum quantum yield of photosynthesis, even though by that time he had already been working on the topic for more than a decade. One of Warburg's first contributions on the subject, which dates from around 1920, is his proposal for a detailed model of photosynthesis, which he never completely abandoned, despite later overwhelming evidence in favor of alternatives. This paper presents a textual and graphical reconstruction of Warburg's model and of his argument for its validity. Neither has received much attention in the history of science, even though the model was certainly one of the most plausible explanations of the period and therefore could not be so easily discredited.

Draughtsmen, botanists and nature: constructing eighteenth-century botanical illustrations.

At first glance botanical illustrations of the eighteenth century might be interpreted as being naturalistic portraits of living plants. A more detailed investigation, however, reveals that the pictures were meant to communicate typical features of plant species in the way of a model. To this end, botanists of the period gave botanical draughtsmen specialist training; copying earlier examples and standardised motives from drawing books was a common part of this training. The practice of copying elements of previously published drawings and integrating them into new pictures was also widespread. However, only carefully selected elements were taken over, and even these were improved in terms of their correctness and appropriateness to the new context. This procedure was a strategy that eighteenth-century botanists used so that they would present an illustration that met their own requirements more satisfactorily than existing depictions. From this perspective, botanical illustrations can serve as historical sources on the working practices of eighteenth-century botanists and draughtsmen, which are usually not mentioned in textual sources.

["We will employ the best engravers for the figures"--draughtsmen and engravers of the Berlin Academy of Sciences, 1700-1809]. / "On employera les meilleurs Graveurs pour les Figures"-- Zeichner und Stecher der Berliner Akademie der Wissenschaften, 1700-1806.

Although barely mentioned in accounts of its history of the Berlin Academy of Sciences, draughtsmen and engravers were, from the very inception, essential collaborators. Based on previously overlooked archival sources, this paper investigates the strategies that scientists used to select the most appropriate candidates during the first hundred years of the academy's existence. These included: (1) the engaging of artists already known to the scientists or those who had been recommendaded to them; (2) maintaining long-term relationships with a number of artists, and later with their offspring (who had frequently been trained by their fathers); in 1768 this strategy culminated in the creation of a permanent position for one academic draughtsman; and (3) hiring draughtsmen who specialised in the subject matter in question, which entailed, for example, employing different people to carry out anatomical and botanical illustrations.