Monday, July 24, 2017


Orly Lewis, Praxagoras of Cos on Arteries, Pulse and Pneuma. Studies in Ancient Medicine, 48. Leiden; Boston: Brill, 2017. Pp. 350. ISBN 9789004337428. $151.00.

Reviewed by Jessica Wright, University of Southern California (

Version at BMCR home site


Frustratingly little has been written on the medical author Praxagoras of Cos (c. late 4th/early 3rd century BCE), despite his recognized influence on later medical and philosophical theories about the human body. From the past century—with the exception of Steckerl's collection of fragments and Capriglione's Italian translation of it—Lewis counts just two studies dedicated to Praxagoras, one of which is a journal article, the other a book chapter (7).1

This neglect is the consequence of two primary obstacles: first, very little of Praxagoras' work survives, and most of it is in the form of third-party description or testimonies rather than verbatim fragments (15-16); second, Praxagoras is most famous for a doctrine that has been damned as a "tragic mistake," formulated without regard for empirical evidence and delaying scientific progress. This was the theory that the arteries (artêriai), as distinct from the veins (phlebes), carried only air (pneuma), and terminated in sinews (neura). That Praxagoras separated the arteries from the veins has been upheld as a watershed in medical knowledge; that he was the first to articulate an understanding of the pulse as a natural (i.e., non-pathological) and constant motion has been all but ignored; his notion that the arteries contain only pneuma and "become" neura has earned him ridicule from ancient and modern readers alike.

Lewis' excellent volume—a collection and re-interpretation of fragments related to Praxagoras' arterial theory—not only disputes this assessment of his scientific contribution, but also lays solid foundations for engaging with Praxagorean theories more broadly. One effect of the stagnation in Praxagorean scholarship is that past claims about his methods, ideas, and influence are repeated uncritically in work on related topics. By opening up questions long thought settled, Lewis has demonstrated the fruitfulness of revisiting the Praxagorean corpus, not only from the perspective of philosophy of science (as, for example, in Michael Frampton's study of voluntary motion, which Lewis critiques), but also with renewed attention to methodology in selecting, framing, and explaining textual "fragments."2

The volume is divided into two parts, preceded by an introduction that lays out the little we know about Praxagoras and sets the agenda for the rest of the book. I discuss each part in turn below.

Part One includes the fragments and Lewis' commentary. The fragments are preceded by a second introduction, which sets forth the rationale for selection and arrangement. Here, Lewis emphasizes both the narrow range of source texts (most of the fragments are drawn from the works of Galen and the Anonymous of Paris) and the broad criteria for inclusion: fragments that mention neither Praxagoras nor Lewis' key terms (arteries, pneuma, pulse) are included if they seem, based on pattern or deduction, to refer to Praxagoras, or if they contribute indirectly to an understanding of his arterial theory, or both.

Lewis collects 33 fragments, inclusive of "testimonies."3 The fragments are organized under four headings: the anatomy of the arteries (fragments 1-3); the physiology of the arteries (fragments 4-15); the relationship between pneuma and soul (fragments 16-20); and pathologies of the arteries and the pneuma (fragments 21-32). Each fragment is presented in the original language with facing English translation, although Lewis is careful to point out that she is not offering a critical edition (23-5).

Lewis' translations are lucid. Her provision of extensive surrounding text for each fragment both in the original and in translation makes the collection bulky and creates a disjointed effect, in contrast to Steckerl's smooth passage through morsels of Praxagorean thought. The choice is nonetheless wise, reminding the casual reader of the painstaking and subjective process through which an editor creates an assemblage of "fragments" out of whole texts, and encouraging evaluation not only of the fragment itself, but also of the lens through which it has been reinscribed by its source text.

Only two of the fragments (frr. 2a and 2b) present themselves as direct quotations from Praxagoras' own writings, and both of these provide different renderings of the same text. Lewis takes this opportunity to reflect upon the problematic nature of the verbatim fragment as it is typically understood. Suggesting that the distinction between "fragments" and "testimonies" might obscure the imprecision of ancient quotation practices (18-19), Lewis stresses throughout the importance of reading always with a view to imported terminology, tendentious framing, and manipulation or misquotation of the original text.

The fragments in this collection are, for the most part, also found in Steckerl's earlier volume. However, Lewis makes a number of vital contributions: (1) new translation of the fragments, relying in some cases on updated critical editions, (2) the inclusion of additional context from the source texts, (3) thematic organization toward a synthetic discussion of important Praxagorean doctrines, (4) reintegration of fragments that were split up and shuffled in Steckerl's collection, (5) reinterpretation of some fragments based on new critical editions of the source texts, (5) the inclusion of a small number of fragments that are absent from Steckerl's collection. Given the extensive overlap between Steckerl's and Lewis' collections of fragments, it is unfortunate that Lewis' volume lacks a concordance for easy reference. Overall, however, the organization of the fragments and their relation to their source texts is clear.

Part Two of the volume, titled "The Doctrines of Praxagoras on Arteries, Pulse and Pneuma," offers a synthetic discussion of Praxagoras' teachings, based on the fragments presented in Part One. It is here that Lewis makes her historiographic intervention clearest, disputing three authoritative claims that derive, ultimately, from Fritz Steckerl. In each case, Lewis emphasizes the difficulty of drawing certain conclusions from the fragmentary evidence. Her focus is upon the need for proper contextualization of fragments within their source text and its framework of reference. Through close reading and careful argument, Lewis reveals the weaknesses in Steckerl's reconstruction of Praxagoras' doctrines and sets forth a more modest account that no doubt will become the standard in future studies.

The first claim Lewis disputes is that Praxagoras developed his arterial theory without practical anatomical experience. Lewis argues, to the contrary, that Praxagoras quite possibly carried out dissections, both in experimental and therapeutic contexts, and that in any case his theorization is clearly based on an understanding of arterial morphology that he could only have gained through observation. Lewis is correct to emphasize Praxagoras' practical experience, especially since it is the perceived falsity of his ideas that have motivated scholars to insist that he worked from theory alone. In some places, however, Lewis is so insistent upon the importance of revising this assumption that she seems to neglect the role of theory in shaping perception. It is not necessary to reject the insight of Steckerl and Frampton that Praxagoras was answering a "theoretical demand" in the development of his arterial doctrines in order to demonstrate that he was also observing material bodies. As historians of science have long since demonstrated, theory shapes not only how scientists and doctors explain what they perceive, but also what they perceive in the first place.4

The second claim Lewis disputes is that Praxagoras thought that arteries actually become neura (sinews). Lewis suggests, rather, that Praxagoras followed Aristotle in understanding arteries as being "like neura" in general, their tips being most neura-like of all. Navigating the complexities of the evidence in thorough, if sometimes overly detailed fashion, Lewis lays out three questions central to this debate: (1) did Praxagoras think that the arteries became neura or only looked like them? (Lewis: arteries looked like neura); (2) did Praxagoras think that the arteries changed anatomically or functionally or both? (Lewis: arteries changed anatomically only); and (3) did Praxagoras think pneuma continued to travel through the neura-like endings of the arteries? (Lewis: yes, he did). What is fascinating in this discussion, as Lewis hints at in her conclusion, is that neurabecame, for Hellenistic authors, the name for the "nerves," that is, vessels though which only pneuma passed in order to enable sensory and motor function in the animal.

Third, Lewis disputes the claim that Praxagoras considered pneuma to be identical with soul, anticipating and laying the foundations for the more famous Stoic theory. While Lewis notes in her conclusion that Praxagoras marks an important development in the history of pneuma, she strongly contends that there is no evidence that Praxagoras equated it with soul. Instead, she demonstrates that pneuma was an instrument of psychic agency, which Lewis attributes to the heart. Lewis' discussion of this question, albeit somewhat dense, is extremely valuable, offering an important corrective to Steckerl's striking but unsustainable theory that Praxagoras understands the soul to be "a kind of mixture of the air which enters the body and of the air which is enclosed in the bubbles" released through digestive processes (292, quoting Steckerl). The broader importance of this argument for the history of the "soul" is clear: as Lewis remarks, the "substance" of soul was simply not an interesting question to medical authors of this period; rather, Praxagoras and his peers sought to identify "the instrument (and physiological infrastructure) of the faculties connected with the soul" (294).

Praxagoras of Cos on Arteries, Pulse and Pneuma is an important contribution to the field of ancient medicine, making accessible to researchers and to students the ideas of a central transitional author between Hippocratic and Hellenistic medical writings. Lewis' writing is repetitive but thorough. Readers seeking a basic grasp of Praxagoras' arterial theory will be well served by reading at least the conclusion, which sets out in clear summary form each of the doctrines discussed. The meticulous detail of Lewis' arguments, meanwhile, lays the foundations for more precise investigation of how theories about the arteries, the pulse, the pneuma, and indeed the nervous system and the soul, developed in the hazy years between "Hippocrates" and Galen.


1.   E. D. Baumann, "Praxagoras von Kos", Janus 41 (1937): 167-85. F. Steckerl (ed.), The Fragments of Praxagoras of Cos and His School (Leiden: Brill, 1958). J. C. Capriglione, Prassagora Di Cos (Naples: Il Tripode, 1983). D. Nickel, "Hippokratisches bei Praxagoras von Kos?" in P. J. van der Eijk (ed.), Hippocrates in Context (Leiden: Brill, 2005), 315-23. There are, of course, numerous studies that discuss Praxagoras in passing.
2.   M. Frampton, Voluntary Animal Motion from Greek Antiquity to the Latin Middle Ages, 400 B.C.-A.D. 1300 (Saarbr├╝cken: VDM Verlag, 2008). Frampton invokes Kuhn's theory of scientific paradigms to explain Praxagoras' argument that arteries "become" sinews, suggesting that this thesis was an attempt to solve a theoretical problem within the Aristotelian paradigm. According to Frampton, following Kuhn, a (paradigmatic) scientific model that includes gaps and inconsistencies will encourage solutions that fit within the same paradigm, rather than total reinvention.
3.   33, that is, counting frr. 2a and 2b separately.
4.   See especially S. Kuriyama, The Expressiveness of the Body and the Divergence of Greek and Chinese Medicine (New York: Zone Books, 1999).

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