galen on the motions of the blood in the heart and lungs

Galen on the Motions of the Blood in the Heart and LungsAuthor(s): Donald FlemingSource: Isis, Vol. 46, No. 1 (Mar., 1955), pp. 14-21Published by: The University of Chicago Press on behalf of The History of Science SocietyStable URL: http://www.jstor.org/stable/226820 .

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Galen on the Motions of the

Blood in the Heart and Lungs

By Donald Fleming *

FEW subjects in the history of science and medicine have been as much disputed in the last hundred years as the discovery of the circulation of the

blood. But the almost universal assumption seems to be that whoever the liberator from false doctrine may have been, the liberation was from Galen. It comes as a surprise, therefore, to find that Galen's view of the motions of the blood in the heart and lungs was misconstrued by some of the leading German historians of medicine of the later igth and early 20th centuries. Moreover, the same error has been borne forward into our own time by the best known historian of science in England, and gravely compounded. The result is that many of the standard reference works on the history of science and medicine now current fundamentally misrepresent the views of Galen on the motion of the blood. By the same token, they afford a false perspective on the discovery of the circulation.

Of the two principal errors involved, the first to intrench itself was the statement that in Galenic physiology blood introduced into the right ventricle is there purified by expulsion through the pulmonary artery (Galen's arterial vein) of waste products variously translated from the Greek XAyv as soot, fumes, or fuliginous materials. These are said to be expelled from the pulmonary artery in turn by expiration through the lungs. Of standard authors still in general use, the first to fall into this error seems to have been the well- known pioneer of academic instruction in the history of medicine, Heinrich Haeser. Haeser frankly admits to finding Galen "quite unclear" on the de- tails of the process - "in particular how he got around the difficulty that the pulmonary artery must serve the double purpose of supplying the lungs with blood and causing the soot to be expelled during expiration." 1 A generation later, Julius Pagel perpetuates the error made by Haeser. The key sentences may be set side by side for comparison.2

Das in der Leber gebildete Blut gelangt durch die Venae hepaticae und die auf- steigende Hohlvene zum rechten Herzen, in welchem, vermoge der demselben einge- pflanzten Warme, die unbrauchbaren Bestandtheile, der "Russ" (Aryvx!s) von

Das in der Leber bereitete Blut geht durch die Venae hepaticae und Vena cava as- cendens zum rechten Herzen, in welchem sich die unbrauchbaren Stoffe als AtXyvs (Russ, Fumus) ausscheiden, um bei der

* Department of History, Brown University. 'Heinrich Haeser, Lehrbuch der Geschichte der Medizin und der epidemischen Krankheiten,

3d ed. (Jena, i875), I: 359-363; the quotation, p. 359. 2Haeser, Lehrbuch, z: 359; Julius Pagel, Einfuhrung in die Geschichte der Medizin (Berlin,

I898), I: 124.

I4



GALEN ON THE MOTIONS OF THE BLOOD 15 den brauchbaren geschieden werden, um bei der Exspiration durch die alsdann sich offnenden halbmondformigen Klappen der Arteria pulmonalis in die Lungen, und von da nach aussen gefiihrt zu werden.

[Haeserl

Ausathmung durch die sich eigens zu die- sem Zwecke offnenden halbmondformigen Klappen der Arteria pulmonalis aus dem Korper gefiihrt zu werden. [Pagel]

A paraphrase by Pagel of Haeser or by both men of a third, unknown source is indicated. Unlike Haeser, Pagel runs up no storm-warning about the doctrine that he is purporting to expound. Still another leading figure, Max Neuburger, reproduces the same error in almost the same language.3

A second major error seems never to have taken root in German writers, and apparently owes its effective origin to Sir Michael Foster's Lectures on the History of Physiology. The critical passage may be cited in its entirety.

Thus from the right side of the heart there is sent to the body generally along the great veins, and to the lungs along the artery-like vein (the pulmonary artery), a flow, followed by an ebb, of crude blood endued with natural spirits only, blood serving the lower stages of nutrition. Blood flows through the artery- like vein (the pulmonary artery) to the lungs for the nourishment of the lungs, just as it flows through the other veins for the nourishment of the rest of the body; in both cases there is an ebb as well as a flow along the same channel.4

This alleged ebb and flow of Galenic tides from the right ventricle of the heart has had an amazingly prosperous career and done much harm; but Foster, unlike the German scholars, did not suppose that in Galen's physiology wastes were discharged through the pulmonary artery.5 Dr. Charles Singer, who took up where Foster left off, in point of time, and soon became the leading British historian of the biological sciences, has grafted both errors on to a single stock.

For the venous blood that entered this important branch, the right side of the heart, the Galenic scheme reserved two possible fates. The greater part remained awhile in the ventricle, parting with its impurities, which were carried off (by the "artery-like vein" - now called the pulmonary artery) to the lung, and there exhaled. These impurities being discharged, the venous blood in the right ventricle ebbed back again into the general venous system.6

The same combination of errors may also be found in Abraham Wolf, Cohen and Drabkin, and S. F. Mason.7 Erik Nordenskiold endorsed the sooty dis-

'Max Neuburger, History of Medicine, Ernest Playfair, trans. (London, I910), I: 256. Cf. Robert Fuchs on Galenos, in Max Neuburger and Julius Pagel, eds., Handbuch der Geschichte der Medizin (Puschmanns Handbuch), (Jena, 1902), I: 398-with citation to Pagel, Einfiuhrung, z: 124.

'Lectures on the History of Physiology during the Sixteenth, Seventeenth and Eighteenth Cen- turies (Cambridge, England, 1901), p. 12.

'Unfortunately, he has got the correct view of this subject inextricably mixed up with still another error, apparently not much imitated: "From the left side . . . there takes place along the arteries to all parts of the body a flow, followed also by an ebb, of blood endued with vital spirits, and so capable of giving power to the several tissues to exercise their vital functions. As this blood passes from the left heart along the vein-like artery (pulmonary vein) to the lungs it carries with it the various fuliginous vapours which, in the fermenting activity giving rise to the vital spirits, have been extracted from the crude blood, and discharges these vapours into the pulmonary passages." Lectures, pp. 12-13.

'A Short History of Science to the zgth Century (Oxford, 1941), pp. 91-92. In his little mono- graph, The Discovery of the Circulation of the Blood (London, 1922), Dr. Singer spoke (p. 13) of the discharge of wastes through the pulmonary artery.

'Abraham Wolf, A History of Science, Technology, and Philosophy in the XVIth and XVllth



I6 DONALD FLEMING

charge from the right ventricle, and H. T. Pledge the ebbing and flowing of blood between the liver and the right ventricle.8 Insufficiently qualified state- ments that Galen believed in an ebb and flow of venous blood are too numerous to mention.9

If, in fact, erroneous views of the subject are current, three questions nat- urally arise: first, what Galen actually taught; second, how this came to be misconstrued; and third, what difference it would make to set the matter right. The present article will address itself chiefly to the first and second questions.

The actual metaphor of the ebb and flow of tides in the blood is used by Galen only to illustrate the kind of absurdity that Nature would not fall into. Yet he does argue strongly for an irregular flow of nutriment back and forth in the veins between the stomach and the liver.

What is there surprising . . . in the fact that the veins situated between the liver and the region of the stomach fulfil a double service or purpose? Thus, when there is abundance of nutriment contained in the food-canal, it is carried up to the liver by the veins mentioned; and when the canal is empty and in need of nutriment, this is again attracted from the liver by the same veins.10

It would be quibbling about words to deny that this may be described loosely as a doctrine of tides. Galen's own comparison is with "animals helping themselves at will to a plentiful common stock of food." 11 Whatever figure of speech is employed, the stuff that is tossed back and forth would seem to be not blood, that is, food elaborated by the liver, but merely food itself.

Of the true blood discharged from the liver into the hepatic veins, in the direction away from the stomach, some though by no means all enters the right ventricle of the heart. It is quite certain that for Galen only a negligible portion of this blood can reverse its direction of flow; and so also with the blood - not soot or fumes - borne from the right ventricle into the pulmonary artery (called by him the "arterial vein"). Galen defends this position by citing both the purposes that are served by one-way traffic in the region of the heart and lungs and the structures that forward it. Otherwise, he says, the blood would always be coming and going, to no purpose and without end, like tides in a strait; the maximum expansion and contraction of the pulmonary veins (called by him "arteries") required for respiration would be obstructed; and

Centuries (London, 1935), pp. 407-408; Morris R. Cohen and I. E. Drabkin, eds., A Source Book in Greek Science (New York, 1948), p. 486; S. F. Mason, A History of the Sciences (London, 1953), p. 41.

'Erik Nordenski6ld, The History of Biology, Leonard Bucknall Eyre, trans. (New York, 1928), p. 64; H. T. Pledge, Science since 1500 (London, 1939), p. 27.

9 Cf., e.g., Herbert Butterfield, The Origins of Modern Science (London, 1949), pp. 36-37; Arturo Castiglioni, A History of Medicine, E. B. Krumbhaar, trans. and ed., 2d English ed. (New York, 1947), p. 222; Fielding H. Garrison, An Introduction to the History of Medicine, 4th ed. (Philadelphia, 1929), p. ii6 (with fn. to Foster); K. D. Keele, Leonardo da Vinci on the Move- ment of the Heart and Blood (London, 1952), p. 56.

10De Naturalibus Facultatibus, bk. 3, ch. xiii; Claudii Galeni Opera Omnia, ed. C. G. Kiuhn (Lipsiae, i82i-i833), 2 (i821): i88-i89. This and all subsequent passages from De Naturalibus Facultatibics are cited in the translation of Arthur John Brock, Galen on the Natural Faculties (London, i9i6); the present passage, p. 293. In each case Brock has been checked against the original Greek and Kuhn's Latin version.

"1De Nat. Fac., 3, xiii; KUhn, 2: 202. Brock, 313.



GALEN ON THE MOTIONS OF THE BLOOD 17

the passing over of blood from the pulmonary artery (his "arterial vein") to the pulmonary veins (his "arteries") would be prevented.'2

Throughout the body the arteries anastomose with the veins and interchange with them air and blood by means of invisible and extremely fine openings. If the great orifice of the arterial vein were always open, and if Nature had not in- vented a means for alternately closing and opening it at the appropriate time, the blood would never penetrate into the arteries on contraction of the thorax.

When the thorax contracts, the pulmonary arteries, with their veinlike tunics, crowded and pushed from all sides with great force, instantly expel the pneuma which they contain, and in return are filled through these narrow channels [anas- tomoses] with particles of blood - a thing which would never have been possible if the blood had been able to go back through the great orifice which exists in this [arterial] vein on the side of the heart. As it is, when the vein is compressed on all sides, the blood finding its passage cut off through the great orifice penetrates in the form of minute drops into the arteries by way of these narrow channels.'3

Galen does not make clear whether the blood that passes into his "venous artery" (our pulmonary veins) is then transmitted to the left ventricle.

Anatomically Galen rests his argument for the substantial irreversibility of flow in the heart and lungs on the same basis that we would employ, namely, the existence of one-way valves at the four apertures leading to and from the heart, so disposed as to keep the blood always moving in one direction and never backward.

. . . since all of these [arteries, heart, thorax, and lungs] dilate and contract alternately, it must needs be that matter is subsequently discharged back into the parts from which it was previously drawn. Now Nature foresaw this necessity, and provided the cardiac openings of the vessels with membranous attachments, to prevent their contents from being carried backwards.'4

These membranes serve their common purpose, of opposing the reflux of matters from the heart and lungs, by constituting two pairs of valves, of which one pair "expels matter from the heart in such a way that it cannot get back in," and the other "admits matter in such a way that it cannot get out again" by the same channel.'5 The excellent account of these valves in Galen is avowedly drawn from Herophilus and more particularly Erasistratus.'6

Though the purpose of the cardiac valves is to impose one-way traffic, Galen holds that they do not function perfectly. In the first place, "if Nature has contrived to prevent any considerable reflux, she has not been able to prevent

"2De Usu Partium Corporis Humani, 6, x; Kuhn, 3 (I822): 454-457. The figure of the tides is from p. 454: K4V TOu7TD rplrov 8 TIT &Troro', a6-r6 re rI at'a KLPr KELyOaL 6LauX6v Tim' TOUTOr dKaTd7ravuorov, 4v ,uev TaTs 8caoroXaZs -ToO rvCuIovos E7rqLpIoV TE Kal 7rX77poUv a7raaas r'S KaT' aiTIv qXWgas, e'v 5e 7Tats avauooXais otov tlf.L7rT'v 7-Lva KLVOVyUEPOV evpIrOu LK77V, del 7f8e K&Keffe ueracazXX6/.tevov oi3a,Cos acz7AaTL rpirouuav topdv. Here and in all subsequent citations from De Usu Partium, I have had constant recourse to the French translation of Charles Daremberg: Oeuvres Anatomiques, Physiologiques et Medicales de Galien (Paris), I (I854): III-706, and 2 (I856): I-21I (the present passage, I: 412-4I4).

'De Usu Part., 6, x; Kuhn, 3: 455-457. Daremberg, I: 4I4. "6De Nat. Fac., 3, xiii; KUhn, 2: 203 KaTca' A6 'yap TaS ipT7?pi7as IKavi4 4ap-ye's I TOLOUTO,

WUtep Kai KaTC TJ7V Kap3iav Te Kai TIPP OWpaKa Kai Tbv wrevEUAova. TOvTWI yap a(ZraVTwV 5taoTEXXo.LvE v

Te KaL ovoTTe7XX/oLuCvwv 'aXX&at, dva'yKalov, t c'V elCXKua01 rc Trp6-epov, eIs TaLUO iaOTepov eK7rifArEcOaL. Kai TaVT7)V &pa Tr7p dvacyK?7v fj OV'aoS 7rpo-yuV'OaKOvaa TOs e'v Tr Kap&It aOT6-0aaL TCP dy-ydEwv V, gvas 9r-ipvoe, KWXVUoVTas els Tor&rlaw 0ipeaoat TAS XAas. Brock, 3I3 and 315.

'f De Usu Part., 6, xi; Kuhn, 3: 460. Daremberg, I: 417. 16De Placitis Hippocratis et Platonis, I, x; Kuhn, 5 (I823): 206-207.



:I8 DONALD FLEMING

although a minute flow" in the opposite direction at the very moment of opening and closing.'7 In Galen, whose chosen task is to vindicate man's body to man, there can be no ultimate imperfection in the human organism, so that this slight reflux of fluids and vapors has to be justified. For once, however, his sense of higher purpose seems to flag and the best that he can do is to invoke in a rather perfunctory way the Hippocratic conception of "everything in everything" and a consensus of fluids.18 He makes no effort to particularize the virtue of all-in-allness in the present context. Since this amounts to a con- fession of failure in the enterprise that he has most at heart, it merely serves to point up the weight of his conviction that with one exception the meaningful motion of fluids in the heart and lungs is forward.

The single exception is the discharge of sooty wastes backward from the left ventricle through the venous artery (our pulmonary veins) for expulsion from the body by the lungs. "This alone [the venous artery] had in fact no advantage in being perfectly closed [to a reversed flow], since it had rather the mission of letting pass from the heart into the lungs the smoky residues which the natural heat necessarily produces in that organ, and which have no shorter means of exit." 1' The discharge of these wastes, against the natural current of fluids in the heart, is made possible according to Galen by the comparative weakness of the mitral valve guarding the aperture between the venous artery and the left ventricle. This valve "alone has to make a passageway for the burnt residues transported from the heart to the lungs." 20 It is from the left ventricle, rather than the right, that wastes are given up in the Galenic physiology.

In addition to the exit from the right ventricle by way of the pulmonary artery, Galen also provides for the passage of blood from right to left through invisible pores in the muscular wall between the ventricles.2' This, the one doctrine of Galen's that is universally known, is seldom misrepresented and does not call for discussion here.

Galen's theory of the motions of the blood in the heart and lungs may therefore be summed up as follows. Blood on entering the right ventricle must pass by a one-way valve opening inward, so that only an insignificant portion can relapse into the vena cava whence it came. Some of the blood passes di- rectly from right to left through the interventricular septum. But much, and apparently most, of the blood moves into the arterial vein (our pulmonary artery) past a one-way valve opening outward from the ventricle. On contraction of the thorax, the blood in the arterial vein, its retreat cut off from behind,

"7De Usu Part., 6, xvi; Kuhn, 3: 49I: cs y&p ilrl Tis TpaXeIas dpTrqpias e7re5elKPvVUeP, d86uvaTov 77pv uIBE',v rap-7OesoOat Tr TC5.P KaTra7ri6rPTrwP 6iyprov, olIrws gXetv Xpi voP,Ure, K4,TwrOaa TroO 7rXi0ovs aCLTWC iSevpj7aOaL T7f t/f0-OE KXv/LCa, Trou 8'e XAcs mf'ov 7rapappelP /L ro1 dXTOO&X rov Y 8TO vaPCrTOP efpEOipai

Tr 9vXaKT7jptov. Daremberg, Z: 440-44I. 8Ibid.

19 De Usu Part., 6, xv; KUhn, 3: 485-486: e6X6oycvw ouv io/' ibs u6,vov To6 OT6,uarTos -roTC T7js

Ae#cb3ovou dprTfptas 3vosv e7rL5ems L,ueYvw EyevoTro. i,6vqo ya&p ToburT feXrToL 7v OVK dKpLficS

KXeIecOac, W5LTL Kai IAOu'C o-VyCwpKiEEP 7)P d/Aepop es TbP 7rire6vr L,uova fr4peOOaL To0 (EK KKap8las Xeyvvu6eat

lrepLtrTrW/. P, a 8L& it eJ' Tiv 7rXriOoX T?m e/tu/Tov OepAaaias dvao'Kacov t'OXEt aLrT' aVPTrO/weTrpaP 8' erTepa,v 0VK eZXeV gKp0?P. Daremberg, I: 437.

2'De Usu Part., 6, xvi; Kuhn, 3: 49o. Daremberg, I: 440. 'De Nat. Fac., 3, xv; Kuhn, 2: 207-208; Brock, 32i. De Usu Part., 6, xvii; Kuhn, 3: 496-498;

Daremberg, Z: 444-445.



GALEN ON THE MOTIONS OF THE BLOOD I9

can only go forward into the arterial system of the lungs (in modern usage, venous). Whether Galen's venous artery, corresponding to our pulmonary veins, then carries blood to the left ventricle is in question. He almost certainly thinks of the venous artery as conveying the inspired air, in some form or other, - or at least some quality derived from the air, - from the lungs to the left ventricle.22 In the opposite direction smoky wastes are undoubtedly borne from the ventricle to the lungs by way of the venous artery. This process is made possible in Galen's view by the comparative insufficiency of the mitral valve opening into the heart. The blood in the left ventricle passes into the aorta through an aperture guarded by a one-way valve opening outward.

To the question, why these teachings of Galen have come to be misunder- stood by scholars of great learning and distinction, no assured answer can be given.23 To say that once an error has taken hold the inertia of scholarship will bear it along merely displaces the problem one step backward. If, however, we discriminate between the two cardinal errors, of a reflux from the right ventricle and the discharge of wastes through the pulmonary artery, certain clues may be found. The treatise De Naturalibus Facultatibus contains two passages which, if taken out of context, would lead one to suppose that Galen believed in a reflux of blood from the heart.

Now the lungs, the thorax, the arteries rough and smooth, the heart, the mouth, and the nostrils reverse their movements at very short intervals and change the direction of the matters they contain. On the other hand, the veins which pass down from the liver to the intestines and stomach reverse the direction of their movements not at such short intervals, but sometimes once in many days.24

In the case of the arteries this [that matter should be carried by the same vessels in opposite directions] is clear enough, as also in the case of the heart, thorax, and lungs; for, since all of these dilate and contract alternately, it must needs be that matter is subsequently discharged back into the parts from which it was previously drawn.25

The second passage only requires to be joined with the next succeeding sen- tence, already quoted, to make Galen's meaning clear: "Now Nature foresaw this necessity, and provided the cardiac openings of the vessels with membranous attachments, to prevent their contents from being carried backwards."

'On the ambiguity, if not internal contradiction, in Galen's views on this subject, see: Owsei Temkin, "On Galen's Pneumatology," Gesnerus, 195I, 8: I82-I84. I Substantially correct accounts of Galen's doctrines are given, without reference to their conflict with other authorities, by the following: J. G. Curtis, Harvey's Views on the Use of the Circulation of the Blood (New York, I915), pp. 57-60; Charles D. O'Malley, ed. and trans., Michael Servetus. A Translation of His Geographical, Medical and Astrological Writings (Philadelphia, I953), PP. i98-igg; Sigismund Peller, "Harvey's and Cesalpino's Role in the History of Medicine," Bulletin of the History of Medicine, 1949, 23: 213-2I5; and J. Prendergast, "Galen's View of the Vascular System in Relation to that of Harvey," Royal Society of Medicine, Proceedings, I927-1928, 2Z, pt. 2 (May-October, 1928): pp. I843-I847. But Professor O'Malley speaks (p. 200) of "the old Galenical idea of the ebb and flow of the blood"; and Drs. Peller and Prendergast seem overly con- fident of Galen's having postulated a pulmonary circulation, with passage of blood as well as air through the venous artery. It will be noted that with the exception of Dr. Prendergast, all of these writers touch on Galen's doctrine merely as an incident in the discussion of something else.

2'De Nat. Fac., 3, xiii; K&hn, 2: i98: 6 rPebuWPv o0P Kai 6 Owppac, Kai al dprT7pIaC al rpaXelaC KaCL al XelaL, Kai Kap8ia, Kai 0oT76/Ca, Kai h'ves lp eXaCX1oTrats Xpoo poXpo 'orals cis i'avTlasL Kt1'?aevs aura Te /eTra#aXXEL Kai raTs 6Xas /.e0oLTi7atu. al 5' et 7"IraTos eis 7Tepa Kai ya7T epa KaOiK0vo-at 9W#es OiK lp oTC,rw PpaXIoL Xp6,ov /.OpioLs, dXX' lv 7roXXal!s /lApaLs &7rat lpioTe T7'p EpaP7Ttap KLPOvTaL KPl1viiov. Brock, 307.

?De Nat. Fac., 3, xiii; see fn. 14 supra.



20 DONALD FLEMING

The first passage is more of a problem. If the heart changes the direction of its contents, surely something must be flowing backwards? But on reflec- tion we can see that this need not be so of an organ, and an organ supplied with separate exits and entrances. Here a change of direction may mean simply that motion toward the organ is followed by motion away from it the current itself moving in one direction only but with respect to the organ in opposite directions. The change in direction of their contained matters, which Galen attributes to the lungs, thorax, arteries, heart, mouth, and nostrils in common, is therefore highly equivocal. A loose collocation of subjects has been linked to an ambiguous predicate. The mouth and nostrils, for example, are not organs but merely external apertures. Unlike the heart, they cannot in themselves close upon and bottle up their contents and then project them out again after a sensible interval. For this reason few people would think of say- ing with respect to air flowing in one direction from the mouth to the lungs, or in the other direction from the lungs to the mouth, that it had first entered the mouth and then gone out again. But of the other kind of change in direction, of the current of the airflow itself, we often have occasion to speak. So the formula, "change of direction," makes two kinds of sense with respect to the heart, and only one with respect to the mouth and nostrils. But of the two kinds of possible discourse about the heart, only one is compatible with Galen's physiology. He cannot himself have been in any real confusion about this point, but it does seem to have been the source of confusion in others.

We have still to account for the origin of the misunderstanding about the discharge of wastes from the heart -why, in the face of Galen's clear statement that this takes place from the left ventricle through the venous artery, many authorities have fixed instead upon the right ventricle and the arterial vein. It seems hardly credible that students of Galen can have confounded the venous artery (our pulmonary veins) with the pulmonary artery (Galen's arterial vein), though this would go far toward explaining the matter. If this suggestion is rejected, one possible clue may be found in the circumstance that if wastes were expelled through the pulmonary artery, one major difficulty in Galen's physiology, as commonly understood, would be cleared up. The difficulty in question turns on the assumption that in Galenic physiology air in some form passes from the lungs into the left ventricle.26 The best statement of the issue involved was made by William Harvey in De Motu Cordis:

It is said that the left ventricle draws material for forming spirits, namely air and blood, from the lungs and right cavity of the heart. Likewise it sends spiritous blood into the aorta. From this it separates waste-vapors which are released to the lung by the venous artery. From the lung spirits are obtained for the aorta. How is this separation made? How do spirits and waste-vapors pass here and there without mixture or confusion? If the mitral valves do not stop the passage of waste vapor to the lungs, how do they stop the escape of air? 27

' For the ambiguity in Galen's pronouncements on this subject, see the reference in fn. 22 supra. 27Exercitatio anatomica de motu cordis et sanguinis in animalibus (Francofurti, I628), p. I6:

Cum dicunt sinistrum ventriculum e pulmonibus, & dextro cordis sinu materiam attrahere, ad spiritus condendos; aerem videlicet & sanguinem, & pariter in aortam spirituosum sanguinem dis- tribuere; & hinc fuligines, videlicet retro per arteriam venalem remitti in pulmones, ilinc spiritus in aortam. Quid est quod separationem facit, & quod modo huc illuc spiritus fuligines citra permis-



GALEN ON THE MOTIONS OF THE BLOOD 21

If only Galen had said that wastes were discharged from the right ventricle into the arterial vein, the problem would vanish. All problems would vanish if their elements were denied, and this was not for Harvey an eligible solution. Yet many modern writers have unconsciously taken just this way out and introduced order and reason into Galen's doctrine by falsifying it. If, however, the discharge of wastes is shifted from the left to the right ventricle, still another problem arises, as Heinrich Haeser saw long ago - "the difficulty that the pulmonary artery must serve the double purpose of supplying the lungs with blood and causing the soot to be expelled during expiration." Yet there is a solution of sorts to this dilemma also - simply to deny that the pulmonary artery does fulfil a double role and to say instead that of that portion of the blood which does not pass through the interventricular septum from right to left, the whole quantity, minus certain wastes, relapses into the vena cava in the direction of the liver. Now, this is one of the two cardinal errors under discussion, and one can see that a rational account of Galen's physiology ought to contain either both of them or neither one. The account given by Dr. Singer possesses this merit of rationality - the rationality of a coherent structure of errors.

When these misconceptions are cleared away, the groundwork is laid for re-examining the relationship between Galen and William Harvey. This will constitute the subject-matter of a second article. Here it may be said sum- marily that Galen's views on the motion of the blood in the heart and lungs, as sketched above, did not in any serious way obstruct the work of Harvey; and Harvey did not suppose that they did.

tionem aut confusionem commeant. Si tricuspides mitrales non impediunt egressum fuliginum ad pulmones, quomodo impedient aeris?

The translation is, with one change, that of Chauncey D. Leake, as emended from Robert Willis; Anatomical Studies on the Motion of the Heart and Blood, 3d ed. (Springfield, Illinois, I941), pp. I8-I9. Dr. Leake evidently mistranslated "arteriam venalem" as "arterial vein," rather than "venous artery"; and then substituted for arterial vein the modern equivalent, i.e., pulmonary artery. This is doubly misleading, in that the appropriate modern term would be pulmonary vein; and more significantly in that Harvey, though conscious of the weakness in Galen's nomenclature and persuaded that the arterial vein ought to be called an artery and the venous artery a vein, did not in fact break with the old usage. But given Dr. Leake's desire to transpose into modem termi- nology, the context of his translation of this passage makes clear that his use of pulmonary artery is merely a momentary lapse and not an attribution to Harvey of the view that Galen believed in the discharge of wastes from the right ventricle.



galen on the motions of the blood in the heart and lungs

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