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This paper will explore the role that hourly timekeeping plays in the fever treatises of Galen of Pergamon. Galen was a physician of the second-century CE, who served three emperors at Rome and whose theories of medicine shaped the practices of western physicians through the 18th century. The present paper will focus on Galen’s theory of intermittent fevers, a theory which was accepted with little question until the 16th century. Even today some of his classificatory terms – such as ‘quotidian’, ‘tertian’ and ‘quartan’ – continue to be used by doctors to describe different strains of malaria. Temporal patterns play a central role in this influential fever system, which Galen develops most fully in the treatises On Crises, On Types, and On the Differences Among Fevers. Galen argues that the timing and duration of febrile attacks could provide a physician with crucial  information, which would help him both to diagnose a patient’s condition and to prognosticate its final outcome. In this respect, Galen seems to have been influenced by the theories of ‘critical days’ that pervade certain Hippocratic texts, and which suggest that illnesses are likely to undergo significant changes (for better or worse) on particular days. The present paper will explore the interesting ways in which Galen adapts and enhances Hippocratic ‘critical day’ theories and how, in the process, he introduces a new ‘critical’ unit of time, unknown to the Epidemics: namely, the hour.

This paper will ask two central questions: (1) Why might Galen have chosen to employ hourly timekeeping in this way? And (2) how original might Galen have been in doing so? Surprisingly, modern scholarship has not addressed these fertile queries. Though Galen’s fever system has been a popular object of study, interest has centered primarily on topics such as the application of humoral theory to Galen’s understanding of fevers and the kinds of distinctions that he makes among fever types. The present paper, drawn from an in-progress dissertation on the role of clocks and hourly timekeeping in Galen’s medical and philosophical works, seeks to remedy this oversight by tackling such questions for the first time. Given the time constraints of the presentation, this paper will hone in on a particular context within Galen’s fever treatises, one in which instances of the term ‘hour’ are densely concentrated: namely, his narratives of individual intermittent fever cases. In these case histories, hourly timekeeping provides the dominant organizing principle, and this paper will investigate the rhetorical purposes that such a strategy may have served. It will also explore the relationships between Galen’s fever case histories and those of his contemporaries and predecessors, in particular, Rufus of Ephesus and the Hippocratic author of Epidemics I and III.


The proposed paper will demonstrate that, when it comes to temporal structuring, Galen both engages with and departs from these other case history models in significant ways. Ultimately, I will argue that Galen’s choice to use a temporal framework centered on hours was motivated by a desire to support several interrelated claims. These include the following: (a) that he, Galen, was a peerless practitioner of ‘demonstration’ (apodeixis), adept both at performing rigorous observations of patients’ symptoms and at constructing logically coherent systems based on those observations; (b) that his work was simultaneously consistent with and an enhancement of earlier Hippocratic traditions; and ultimately, by extension, (c) that Galen was a superior physician to his contemporaries. This investigation will provide a rare and valuable case study of how a prominent physician incorporated hourly timekeeping technology into his medical practice as well as his medical politics. It should be of interest to scholars from a range of sub-disciplines, including ancient medicine, timekeeping, rhetoric, and the cultural climate of the so-called ‘Second Sophistic’.