Introduction Albrecht von Haller (1708–1777), the Swiss polymath, is best known in the history of medicine for his concept of irritability and sensibility. His orations De Partibus Sensilibus et Irritabilibus, delivered in 1752 and published in 1753, caused a European controversy about the function of nerves and muscles and about the properties of the living body in general. They were translated within two years into French, English, German, Italian and Swedish, and have since then been considered a classic of medical literature.1 No general history of medicine skips Haller’s contribution to physiology or ‘animal economy’, as it was often called in these days. Haller claimed to have proven by animal experiments that only the muscular fibre possesses the ability of contraction, which he called irritability and which was responsible for movement. From this property he strictly distinguished sensibility, responsible for sensual impression and inherent only in the nerves and the parts furnished with nerves. Thus he challenged the traditional, mechanical – mainly Boerhaavian – model on three main points. First, Haller postulated a force inherent in the muscular fibre and independent of the nerves and the soul. Second and partly as a result of this, he separated – conceptually and physically – the two properties of movement and sense perception. Third, and again in part resulting therefrom, he established a strict correlation between structure and function, not on the level of corpuscules or elementary particles, however, but on the level of compound structures, ie. the muscular and nervous fibres. Several well-balanced, general descriptions of Haller’s concept have been published.2 Maria Teresa Monti and especially François Duchesneau have furnished detailed and illuminating conceptual analyses of his theory.3 Duchesneau, Roselyne Rey and others have located it within the general development of physiological models and have worked out its differences from the theories of leading mechanists (Boerhaave, Caldani), animists (Whytt), semi-vitalists (Fontana) and vitalists (Bordeu, Barthez, Wolff, Blumenbach, Hunter).4 The notions of irritability and sensibility of many minor authors have been presented in brief summaries by Jörg Jantzen and some other scholars.5 The contributions of Duchesneau and Rey reflect the epistemological turn in the history of biological sciences, initiated by George Canguilhem.6 Like Canguilhem, they focus on the structure of concepts rather than on the 7 © Hubert Steinke, 2005 | doi 10.1163/9789004332980_002 This is an open access chapter distributed under the terms of the CC BY-NC-ND 4.0 Hubertlicense. Steinke - 9789004332980 Downloaded from Brill.com09/28/2021 10:41:13AM via free access Hubert Steinke broad outline of theories and describe them as models answering a specific set of problems. Nevertheless, like the traditional descriptions of the history of physiology, they are mainly dealing with abstract ideas. The new science studies emerging in the 1980s, however, have stressed that scientific and medical research and the establishment of knowledge are not only theoretical but practical and social processes as well. Ian Hacking, Frederic Holmes and David Gooding have described scientific research as an investigative procedure, during which new concepts are created thanks to a combination of careful practical examination and theoretical conceptualization.7 Somewhat more sociologically orientated, Bruno Latour, Steve Woolgar, Karin Knorr-Cetina, Hans-Jörg Rheinberger, Michael Hagner, Steven Shapin and Simon Schaffer have argued for the social construction of knowledge in the laboratory and in the scientific community at large.8 My aim is to follow the traditions of both the historico-epistemological analysis of physiological theories and the newer science studies. I will, therefore, on the one hand examine the content and structure of Haller’s concept – and, to a smaller extent, those of some other eighteenth-century physiologists – and on the other hand describe Haller’s practice of research and the practical issues and social factors in the subsequent debate. But rather than using the historical case to argue for a specific model of how science works – which is the case for most science studies – I would like to employ the approach of modern science scholars to shed some new light on the development, modulation and reception of Haller’s concept of irritability and sensibility. This study deals with the social construction of medical knowledge. Thus it acknowledges the existence of both social elements and the independent life of nerves, muscles, dogs, cats, and human bodies as parts in the controversy.9 It is less concerned with broad sociological theories than a reconstruction of relations between objects, thoughts, persons, and institutions located in a specific historical setting. In the first part I will discuss the development of the new concept. As the term ‘development’ suggests, Haller’s theory should be considered as the result of an ongoing research process. The experimental investigations in the years 1750–52 lie at the heart of this development that provoked the essential turn in Haller’s conception, a turn that led to the rejection of all earlier notions of movement and sensation – including his own. There was no single experiment that might be called ‘crucial’ but rather the whole experimental process, including practical exploration and theoretical reflection. In my description, I will draw on the laboratory notebooks of Haller and his pupil Johann Georg Zimmermann which, quite surprisingly, have never previously been studied (Chapter 2). By this, I hope to attract attention to the animal experimentation that lies at the core of Hallerian 8 Hubert Steinke - 9789004332980 Downloaded from Brill.com09/28/2021 10:41:13AM via free access Introduction physiology but that has been neglected compared with the theoretical aspects of his work.10 Haller, of course, did not develop his new concept in a space void of theories. Several major authors in the seventeenth century – notably Harvey, Glisson, Baglivi and Borelli – put forward notions of animal motion which were inconsistent with a purely mechanical description of animal economy (Chapter 1, under The heritage of the seventeenth century). However, as I will argue, the Dutch school of Boerhaave and his pupils was of greater importance for Haller. The epistemological approach – predominant in modern research on the history of eighteenth-century physiology – focuses on the general conceptual frame of major theories and tends to neglect the continuous development of models. Not only do the models of major authors change, but also ‘minor’ authors with less elaborate theories may have furnished important new insights. Boerhaave, who represents the mechanical model par excellence, modified his concept over time and, in his late years, whilst maintaining the general mechanical framework, even assumed the existence of an innate bodily property responsible for movement. Bernhard Siegfried Albinus, Frederik Winter and others of Boerhaave’s pupils developed this idea even before their master and made it an important pillar in their physiological research (Chapter 1, Boerhaave and the Leiden school). Haller’s early notions of animal motion were very similar and presumably heavily indebted to those of his Dutch colleagues. New evidence gained from animal experimentation, however, suddenly cleared his early, rather vague ideas and led him to a new understanding of animal motion and sensation. But his formulation of 1752 was not a definitive statement. Even more than Boerhaave’s, Haller’s notions changed. His later statements often indicate not only adjustments but also important modifications of his initial position (Chapter 3). And these changes were, in part, a reaction to the shift in physiological thought that his work – and that of others – had brought about. In the second part of the book, I describe the reception of Haller’s work and address the chief aspects of the controversy it provoked. Modern scholars agree that Haller’s work was a main point of reference in the physiological thought of his time. François Azouvi, for instance, states that it ‘dominates’ Haller’s century and that it ‘constitutes undoubtfully the monument upon which all physiologists of the second half of the century decided, for or against Haller.’11 But what does ‘dominant’ mean? Azouvi is an author mainly interested in the structure of theories. For him, Haller’s theory was dominant because it offered a new and convincing concept that all serious contemporary physiologists had to deal with. This should not, however, lead us to the notion, prevalent in modern general histories of medicine, that ‘Haller’s concepts of irritability and sensibility achieved 9 Hubert Steinke - 9789004332980 Downloaded from Brill.com09/28/2021 10:41:13AM via free access Hubert Steinke widespread acclaim’ or ‘widespread acceptance.’12 Quite generally, we do not know to what extent the ideas of the most original theorists, as displayed for instance in Duchesneau’s La Physiologie des Lumières, were shared by general practitioners and the wider Republic of Letters. Esprit Calvet (1728–1810), professor of medicine at Avignon, for instance, developed notions of sensation and motion peculiar to himself and seems not to have been disturbed by the latest discussions in Montpellier, Paris and elsewhere, even though he knew of Haller’s work.13 There seems to have been a wide variety of notions and ideas, which