Physiology, for long stretches of its history, has been an act of visualizing, i.e. making the functions of the body and its organs visible to both the scientific community and the general public. Anatomy had it much easier in this regard. Visual imagery was fairly easy to acquire and public autopsies became popular ventures in the early modern period (even until today, if you look at Gunther von Hagens's Body Worlds exhibitions). Physiology, on the other hand, deals with the function of the organs rather than their topography, and medical scholars in the past struggled to understand it, and consequently to visualize it. It is thus not surprising that the visualization was actually part of the process of gaining insights and of theorizing about bodily functions, blurring the boundary between illustration and imagination. Diagrammatic illustrations became part of the research, which was as much about science as it was about philosophy.

Tanja Klemm's book is based on her doctoral dissertation in art history at the Humboldt-University in Berlin (2009) and deals with this tension of imagery and knowledge production in physiology in the Latin medieval and Renaissance periods. The book is organized in two parts: first, the history of ideas in relation to the corpus animatum (the animated body) is discussed by Klemm to establish her methodological approach; second, a number of exemplary studies on Leonardo da Vinci, Albrecht Dürer, Lucas Cranach the Elder and Martin Schongauer are contemplated to implement the methodological framework of the first part.

The author introduces two different concepts of image in the book to create this framework: on the one hand, ‘image’ is regarded as a phenomenon linked to bodily functions, i.e. as physiological process (pp. 12 ff.); on the other hand, she introduces a definition of ‘image’ that is relational and embodied, i.e. ‘artist, image and observer cannot be separated categorically’ (p. 272, my translation). With the former, she distances herself from – in her words – the ‘favoured’ theory of images and their perception found in Renaissance studies, which sees images as purely epistemic phenomena, i.e. as visualizations of scientific findings. Rather, Klemm argues, the image is part of the process of physiological inquiry and not a separate step. The image (in)forms the understanding of physiology and vice versa, hence the title of the book: Bildphysiologie, which could be translated both as ‘physiology of the image’ and as ‘visual physiology’. This connection of image and physiology Klemm attributes to the relation of conceptio to perceptio in medieval and Renaissance thinking, as she elaborates in the course of the book.

In the period she is investigating, the relationship between image and physiology is quite apparent. Art was heavily influenced by religion and its image of the world. The visual canon was consequently imbued with spiritual ideas. As a matter of fact, physiology was – just like anatomy – highly topographical at the time. Klemm points to eminent medieval authorities in medical knowledge, such as Hildegard of Bingen, who located properties of the soul in certain organs (p. 55), i.e. these scholars created maps of those properties, linking properties of the soul to parts of the body. Visualizations of physiology in this historic period – of which Klemm gives ample examples – are therefore often similar to maps, showing the sites of character traits in the body, among other things.

Tanja Klemm discusses these topics of image, imagination and science quite extensively. Unfortunately, it has to be said, this wholesale approach confuses the reader at times for its lack of focus. While the book offers a nice compendium of medical theories and philosophy of Christian medieval and Renaissance Europe, and in its second part displays a plethora of contemporary images from aforementioned artists, the breadth of her approach does not make for an utterly interesting read. Her style is rather descriptive and could have done with more emphasis on particular trains of thought. In her attempt to catalogue a broad range of ideas (and images) she fails to create a coherent – let alone compelling – narrative. Her discussion of the relation between conceptio and perceptio, between the image of physiology and imagined physiology, is a very promising one; her glimpses into the debate about embodiment in cognition research, or between phenomenology and physiology, would have opened up great opportunities to put her work into a larger context. Unfortunately, the book lacks the contextualization in terms of history of ideas and history of medicine to satisfy historians of science (and others). This might be a somewhat unfair statement, given that the book is clearly situated in art history, yet it deals with the history of medicine and would have thus merited a better contextualization. The lack of focus is also made apparent by the rather short conclusions (seven pages), which are not even called ‘Conclusion’ and on the first two pages do not even look like one, as she discusses an engraving that has not before been shown in the book, rather than reflecting on her argument, for example.

So while the book deserves some credit in dealing with an interesting and important topic, the style and narration could be much improved. The style is rather dry and readers need a good knowledge of German in order to read it, as the linguistic style is probably not the most accessible one for non-native speakers. The book has, especially in its second part, a wealth of images, which are easy on the eye but make one wonder again whether less would have been more.