The thorax in history 1. From ancient times to Aristotle · Thorax, 1978,33, 10-18 Thethorax in...

Thorax, 1978, 33, 10-18

The thorax in history 1. From l

ancient times to AristotleR. K. FRENCH

From the Wellcome Unit for the History of Medicine, University of Cambridge

Introduction

During most periods of human history dissectionof the human body has been impossible, prin-cipally because of religious aversion to the per-petual disfigurement of the body in the afterlife.Yet man naturally had a great curiosity aboutthe nature of his inside, and in the absence ofdirect observation he had to resort to a numberof indirect methods. We can speak of the anatomi-cal ideas generated in this way as 'knowledge'because they were held to relate to the real world,and they played the same part in the science of thetime as anatomical ideas do now: they belongto the history of anatomy as much as morpho-logical ideas judged on modern criteria.We may list the indirect ways of learning about

the internal structure of man as follows:(1) analogy with animals;(2) inferences from the externally visible

structures of man;(3) from natural philosophy as a whole; and(4) from function.We shall see each of these at work while man wasattempting to discover the structure and functionof his own thorax. In subsequent papers we shallsee how ideas generated in these ways were trans-mitted to later generations and competed, up toat least the time of Harvey, with ideas about thethorax derived from observation. The problemsthat Harvey solved were Greek problems, notthose of the seventeenth century alone.

Let us start with the last of our categories, howideas about the thorax were generated from ideasabout function. There are a number of what wemight call fundamental physiological observationsthat primitive and archaic man made about theliving body. The living body is warm, it breathes,and it moves with an innate motion and inreaction to external changes-four things it doesnot share with the dead body. The principle oflife was therefore hot, mobile, associated withbreath, and, it was widely thought, it preserved

some kind of life of the individual after the deathof the grosser physical body. It was natural tothink that this principle of life had some locationin the living body, and many early natural philo-sophers gave considerable thought to the problemof which organ was the seat of the soul. Thestructural knowledge they employed in this matterrested on what we might call fundamentalanatomical observations, which parallel the funda-mental physiological observations just listed. Theseanatomical observations concern the first two ofthe categories listed at the beginning of this paper,that is to say, most primitive peoples have, andhad, a knowledge of the internal organs roughlyat the level of the butcher or cook who preparesan animal for the table. The major organs wereknown, and there was a rough idea of their rela-tions in the body. The smaller mammals areprepared for the table by the removal of thepaunch and pluck: the abdominal viscera arefirst removed and then the heart and lungs areremoved together from the thorax. The disem-bowelled abdomen of mammals reveals two majorvessels branching into the limbs posteriorly anddisappearing through the diaphragm anteriorly.Observation of the external features of man re-vealed major vessels also through the length ofthe neck. It was natural to assume a continuityof the two sets of vessels through the thorax,which was less open to direct observation, even inanimals, as it was defended by the ribs and itsinternal details were removed in the pluck. Itwas clear that the heart was in some way con-nected to vessels, but it is characteristic of earlyphysiological and anatomical speculation that thisconnection was not elucidated until anatomy be-came a recognised discipline. Yet the heart hadwhat most of the early soul-searchers were lookingfor. It was at the centre of the warm body andwas perhaps therefore the source of that heat; itwas mobile with an innate mobility discoverablein the pulse, a mobility which increased with themotions of the body. The motion of the heart was

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The thorax in history 1. From ancient times to Aristotle

also clear in anger and fear, and it clearly reactedin surprise to sudden external changes. It seemedto share most of these characteristics with the lifeprinciple, the attributes of which had beenarrived at from the physiological observationsabove. Was not the heart the seat of the soul?Many societies have thought so. The Egyptianstreated the heart with reverence during embalm-ing, replacing it in the body cavity or preservingit separately in a jar. In contrast, the brain wasconsidered worthless and was removed piecemealthrough the nose with a hook. The heart and itsassociated vessels were central to the physiologyof the living body in Egypt. The pulse was theheart 'speaking' through the vessels; the vesselscarried from the heart the secretions and humoursnecessary to every part; the vessels were re-sponsible for pathological conditions; and theycarried the 'breath of life' and the 'breath ofdeath'. The heart was also important in ancientIndian medicine, and the structures by which itcommunicated to the rest of the body, the vessels(blood vessels, nerves, 'sinews' in general, allregarded as similar and grouped under the samename), were in both cultures treated to anumerological symmetrisation in a scholasticmanner.'

PNEUMA, PSYCHE, AND THYMOSWhile the heart seemed to have most of thecharacteristics expected of a corporeal seat of thesoul, it did not have all. The exception was thatthere was no obvious anatomical pathway for thesoul-bearing breath to reach the heart. The searchfor such a pathway caused many of the difficultiesof the later period when anatomy became adiscipline, and it also opened the way for othertraditional ideas on the soul and on the body toenter the physiological history of the thorax. Wecan see these ideas most clearly in early Greekthought. Firstly, there was the traditional notionof at least two distinct souls in the body. TheHomeric warrior's individuality and personalimmortality were ensured by his psyche, and hislife-energy, heat, motion, and the more materialaspects of life were the properties of a breath-soul, the thymos. The breath soul was part of thecommon life of the universe, breathed in at thefirst breath of the infant and expired at the lastbreath of the dying man, returning to the worldsoul. In later Greek thought the idea was taken upby the stoic philosophers, who held that pneumawas the life-stuff of man and the universe and thatin its various forms it was responsible for most ofthe activity of the physical world.

In Homer the psyche resided in the head while

the thymos was contaired in the chest. This earlydistinction between the locations of the differentsouls was greatly elaborated by later Greekphilosophers and formed a basis of physiologicalthought for the next two thousand years. Thebrain as a possible seat of the soul came to at-tention largely as a result of empirical observationof the results of wound damage. While the rationalphysicians of the settled civilisation of Egyptbuilt up their scanty anatomical and physiologicalknowledge of the heart and vessels into anelaborate and scholastic scheme of bodily function,the surgeons' empirical observations, collectedtogether for the professional purposes of prognosisand advice on whether or not to treat a certainkind of case, were not intended for system-building, and no extended scheme of the functionof the brain and spinal cord was constructed. Ina word, the central nervous system was not dis-covered, although the observations by the Egyptiansurgeons on the results of damage to the brainand nerve cord are surprisingly acute.2 The ex-periences of the soldiers of the warring tribes ofearly Greece do not reflect, any more than dothose of the surgeons of Egypt, the physiologicalsystem-building of the physicians of a settled civil-isation. They were only too well aware of theresults of damage to the brain, and it is probablyfrom these experiences that the psyche was saidto exist in the head, a blow to which could causeloss of consciousness while the coarser thymoscontinued to vivify the corporeal body.3The other tradition that enters the story at this

point is the relationship of the liver to blood. Itwas widely held that blood was manufactured inthe liver, and its central place in physiologicalschemes was perhaps represented by theBabylonians' use of the liver in divination. Theliver was also seen to be obviously connected toone of the fundamental pair of vessels to be seenin the eviscerated abdomen of animals. The othervessel of the pair was connected to the spleen, thehomologue of the liver on the opposite side of thebody. Now, the various views about the natureand functioning of the body that we meet in theearly Greek schools of medicine are compromisesembodying more or less of these traditional ideas.Those who were convinced that the brain was theseat of the vivifying soul and who thought thatthis soul was derived from the surrounding air (orworld soul) by means of the breath naturally heldthat the breath was drawn into the brain throughthe nose. It followed that the influence of thesoul, or the quality of the inspired air, was trans-mitted to the rest of the body by the vessels, andfor this reason we find that some early accounts

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of the vessels make the fundamental pair, assumedto be continuous throughout the body, take theirorigin from the brain, with only minor connectionsor inosculations with the heart, liver, and spleen.In contrast, those who believed that the heart wasthe seat of the soul were obliged to postulate ananatomical pathway from the lungs to the heart.As we shall see, this was not difficult before thecardiac valves were discovered, but thereafter itcaused a great deal of trouble. Secondly, they hadto postulate that the vessels arose in the heart andcarried the influence of the soul from it to the restof the body. There are greater morphologicalgrounds for this assumption than for the state-ment that they arise in the brain, but the ana-tomical battle fought for the hepatic, rather thancardiac origin of the veins was longer lasting.Notice that all these anatomical statements implyan understood sense of functional direction: thereneed be no morphological distinction between thestatement that the vena cava 'arises' in the liverand the statement that it begins in the heart. Thewriter is thinking not in morphological terms, butin terms of the faculty which the veins werethought to possess and the direction of flow of thecontained fluids. Thus those who held that thevessels arose in the brain described the comingtogether of many fine 'origins', in the manner oftributaries; this is morphologically identical tosaying that the fundamental pair of vessels ramifyinto the head, as some of the 'cardiocentrists' be-lieved. As in the case of the postulated pathwaysfor respired air, in this case it is physiologicalconsiderations that determine the anatomicalstatements.

The early Greek writers

HEART OR HEAD?The question whether the heart or the headwas the dominant organ of the human body, theseat of the soul, was debated among the pre-socratic philosophers of Greece. It is sometimessaid that Alcmaeon dissected out the eye and ob-served the optic chiasma and the connection of theoptic nerve with the brain, but it seems probablethat there is a confusion in an important passageof Chalcidius,4 and that these feats should insteadbe attributed to the later Herophilus (a fact whichdoes not emerge from the usual sources). At allevents, Alcmaeon had a theory of knowledgebased on sensation, and he held that the seat ofunderstanding was the brain.The influence of Alcmaeon (and of Pythagoras)

is said to have been strong in the medical schoolof Croton, and the belief that the brain was the

centre of consciousness and the senses becamecharacteristic of that school. During the sixth cen-tury BC other medical schools were also develop-ing in Sicily, for example, and at Cnidos and Cos.The influence of Empedocles was felt in theSicilian school, and it was consequently main-tained by the Sicilians that the heart was the mostimportant organ in the body and respiration themost important function; they were 'cardiac pneu-matists' in the sense we have discussed above.Empedocles had also said that the body containsfleshy tubes which contain blood and which openout at their fine distal terminations at the skin,drawing in and expelling air as the blood sank androse in the vessels. This notion became importantwhen the later distinction between air and blood-carrying vessels (ie, arteries and veins) was made,as we shall see. The importance of inspired air asa carrier of life is clear from this idea, whichdid not of course preclude air reaching the heartthrough the normal respiratory channels. As forthe other medical schools, that of Cnidos reflectedthe teaching of the Egyptian physicians, and it ispossible that the traditional attention paid to thehLart and vessels in Egypt led here to a distinctionbetween arteries and veins. The school of Cos wasthe traditional home of Hippocrates, and theanatomical ideas of the Hippocratic writings arediscussed below. Most of what we know aboutthese early schools and persons is derived fromfragments, and we should be careful not to imputetoo elaborate a physiological scheme to any ofthem. While we have some information as to theiropinions of the most important organ of the bodywe are not so sure about their ideas on the loca-tion of the different souls, the psyche (or nous)and the thymos (or pneuma). For example,Philolaus in the fifth century, although influencedby the Croton school and believing that the mind,nous, was in the brain, held also that the soul,psyche, was in the heart. Philolaus also believedthat the umbilicus was a third organ of majorimportance in the body, responsible for growth.In effect, Philolaus had distinguished between arational, vital, and vegetative faculty, an idea thatassumed major importance in biological historythrough its elaboration at the hands of Plato,Aristotle, and Galen."Many of these ideas are found in Plato, some of

them from Philolaus through Plato's physician,Philistion. Plato's purpose in the Timaeus was notanatomical or physiological, and the only interestwe have in the work in connection with the historyof the thorax is that in it the fragmentary remarksof the presocratics are extended. In the Timaeuswe find suggestions of the fundamental pair of

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vessels, ramifying in the head; of importantvascular connections of the heart; and of a strangenetwork of pathways of air, fire, and perhapsblood, existing both inside and outside the thorax,which seems to owe something to the respiratoryfunction of the Empedoclean fleshy tubes. Muchmore important in the Timaeus is Plato's descrip-tion of the three souls of man, a hierarchy ofbodily control that owes something to presocraticideas we have now met and which Plato elaboratedin a political form in the Republic. No doubtPlato's political ideas were the father of hisbiological: the highest soul of man, the rational,is located in the head, that part of the body nearestto the heavens whence the soul came, and itspolitical counterpart in the constitution of a polisis the ruling class of philosopher princes, whoalone have the wisdom to rule. The lowest soul isrelegated to the liver, where its duties includenourishing the rest of the body and its weaknessesinclude the baser emotions and desires. Its politicalcounterpart is the lowest social class of workers,whose products are useful to society but whosebase instincts have to be controlled. Of direct con-cern to us is the soul that Plato describes betweenthese two. The vigorous, fiery soul, located in theheart, with the courageous attributes of thewarrior class, has its origins in the vaporous

breath soul of the old tradition: Plato called itthymos. 7

EARLY ANATOMICAL DESCRIPTIONS

One of the earliest accounts of the vessels8 thatsets out to give an anatomical description of themis that of Syennesis of Cyprus, as reported byAristotle.9 This account makes little anatomicalsense if our criterion is modern morphology, butin the context of early Greek thought we can see

at once its position in tradition. Thus there is a

basic pair of veins, continuous from abdomen tothorax. The connection of each vein of the pairwith the kidneys is noted, and that with the liveron one side and the spleen on the other. As inother traditional accounts, including Plato's, thevessels are said to cross from right to left and viceversa. The vessels are said to arise from theumbilicus (perhaps because of its fetal impor-tance) and consequently they have but little con-

nection with the heart, which is what we wouldexpect in a non-cardiocentrist physiology. Themost obvious of such physiologies was the cere-

brocentrist, and an example is that of Diogenesof Apollonia. He was a pneumatist, believing thatair was the fundamental substance of the universe,the intelligence of the macrocosm, and, whenbreathed into man, the giver of life and intelli-

gence. Air first reached the brain and left its bestparts there, bestowing sense perception and under-standing, and then passed to the rest of the bodyin the vessels with the blood. The heart does notplay a major role in the format of the vascularnetwork, which is again in the form of a ramifyingfundamental pair that is most obvious in theabdomen and which passes unchecked throughthe thorax, giving branches to the heart, up to thehead. Again, the vessels on one side of the bodyare called hepatic and those on the other splenic,either because of their attachments to the liverand spleen or because these organs served to givetheir name to the right- and left-hand side of thebody.Much of what is common to the authors

mentioned by Aristotle appears also in the worksof the Hippocratic corpus. The cerebrocentrist TheSacred Disease'0 describes a fundamental pair ofvessels coming to the brain from the liver andspleen, and it gives an account of the downwardextension of these vessels past the kidneys andinto the limbs. Branches are given off in thethorax to the heart, and in general there is amarked similarity to the description given byDiogenes, down to the details of the superficialposition of the vessels in the neck. A more ex-tended account of the vessels was given byPolybus, said to have been Hippocrates' son-in-law and said by Galen to have taught the genuineopinions of Hippocrates. According to Polybus,there were four pairs of vessels, all descendingfrom the head, two pairs of which descendedthroughout the body, lying on either side of thebackbone as in other accounts, and the remainingtwo pairs of which served the lungs, the kidneys,and the spleen and liver on either side. Apartfrom this doubling-up of numbers, this account isin close agreement with the traditional schema.In addition to this, the Hippocratic On the Natureof the Bones" gives an account of the vessels thatis similar to but not identical with the one attri-buted by Aristotle to Syennesis, and Aristotle'sversion of Polybus' account turns up again in theHippocratic works On the Nature of Man'2 andOn the Nature of the Bones. The HippocraticEpidemics 11 contains an account close to that ofDiogenes.There is evidence that these Hippocratic and

Aristotelian versions do not depend on each otherbut represent some common source. Their inde-pendent appearance in different bodies of writingargues that they represent an important scheme ofvascular organisation in the pre-Alexandrianperiod; in all cases there is a fundamental pair ofvessels running the length of the body on either

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side of the spine, giving off branches to im-portant organs. In all cases the heart is not ofcentral importance; Syennesis, Polybus, and, ineffect, Plato giving it no communication to thesystem, only Diogenes and the author of TheSacred Disease granting it branches from thefundamental pair. In all accounts except TheSacred Disease the vessels are said to cross atsome point from one side of the body to the other.In all accounts except Plato's the importantorgans served are the liver and spleen, the kidneys,and the genitalia. What all the accounts have incommon is that they are not cardiocentric, andthere is distinct evidence that some at least repre-sent pneumatic cerebrocentrist opinion. That theyagree in this particular is due partly to the factthat Aristotle selected these opinions for refuta-tion, since they all disagreed with his owncardiocentric view.To summarise the position we have now arrived

at, we find that there was considered to be a

fundamental pair of vessels in the body, the vena

cava and aorta of modem terminology, which,observed in the gutted abdomen of animals inclose relation to the kidneys, spleen, and liver,were thought to extend as continuous vessels tothe brain. Some connection was admitted to theheart, and some account was taken of traditionalviews that gave the heart a sensory function. Thewhole system was symmetrical, containing uni-formly blood alone or with spirit derived from theinspired air. The fundamental pair of vessels was

the product of analogy with animals and observa-tion of the external features of man; thefunctional direction and pathways of these vesselsand their branches in the body were determinedby considerations derived from natural philosophyas a whole, that is, the life-giving macrocosmicpneuma and its entry into the body.

ARTERIES AND VEINSThis picture was radically altered by two dis-coveries: the first was gradual recognition of thedistinction between arteries and veins, and thesecond was the discovery of the cardiac valves.The second discovery was not made until anatomyhad become a discipline in its own right, and thestory of its effect on these traditional ideas willbe discussed in the next paper. The distinctionbetween arteries and veins seems to have beenmade on two grounds. Firstly, it was noticed thatsome blood vessels, phlebes, had thicker coats of arougher texture than others. Secondly, it was

found in the dead animal that some vessels con-tained not blood, but air. No doubt animals werekilled by having their throats cut, or at least the

blood was drained off before butchering, and thearteries, but not the veins, would be foundempty. It is sometimes said'3 that Alcmaeonfound that some phlebes contained air. It is alsosaid'4 that Euryphon, a Cnidian contemporary ofHippocrates, distinguished between arteries andveins, noting, however, that both contain blood.He presumably made the distinction by reason ofthe speed by which blood is emitted when arteriesand veins are cut in the living animal, or from thedifferent structure of the venous and arterialcoats. Now, the discovery that some vessels in thedead animal appear to have carried air in life wasparticularly acceptable to the pneumatists, andthe notion of air- or spirit-filled arteries developeda strong tradition of its own, as we shall see.Phlebes remained in use for 'vein', while arteriacame to be used as 'air-carrying vessel'. As suchit included the trachea, which was subsequentlyknown until the seventeenth century as the arteriaaspera, 'harsh' from its cartilaginous texture;arteria was part of the respiratory system, whetherthe part from the mouth to the lungs, from thelungs to the heart, or from the heart to the body.Secondly, the distinction between arteries andveins meant that the fundamental pair of vesselsof the abdomen was no longer a symmetrical pair,for one was an artery and one a vein. Henceforththe terms 'hepatic' and 'splenic' came to indicate'vein' and 'artery', or, more precisely, vena cavaand aorta, and not merely the visceral relationsof the vessels or their right- or left-hand location.Yet the different structure of these two vesselsimplied a different function. The hepatic vesselwas after all clearly connected to the liver, whichwas often thought of as the source of blood, andit was widely agreed that this vessel was indeedfull of blood, the food of the body. Did it not havea nutritive function? Did not then the artery havea respiratory, spirit-carrying function?

THE WRITING OF ARISTOTLEWhile many agreed that the vessels did havethese functions, Aristotle did not. He did not in-deed believe that pneuma was breathed into thebody; the breath was simply air, to cool the innateheat of the heart. Pneuma, like this heat, wasinnate, and it acted as a bodily agent of the soul.Aristotle stood firmly in the cardiocentrist tradi-tion, and in his biological writings we have for thefirst time an extended account of researches under-taken for reasons of intellectual enquiry andteaching. Unable to dissect the human body, heexamined the validity of the indirect ways of gain-ing anatomical information mentioned at thebeginning of this paper. His extensive researches

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in the structure and function of animals15 weredesigned to supply the causes and principles thatlay behind the appearances. His theory of know-ledge claimed that true knowledge was knowledgeof the fourfold causality of every natural change,the most important of which was final causality,revealing the purpose that lay behind the processof change. Other writers, like Galen'6 and theauthor of the Hippocratic De Corde,17 took thispurpose to be the rational plan of a personalisedand craftsmanlike Nature or Creator, andanatomical and physiological work then becamean exercise in revealing the skill and wisdom withwhich the body had been put together. The bodywas in this way worthy of attention for its ownsake, not merely as a means of achieving medicalpurposes, and anatomy became a discipline, withits own methods of procedure, and formalisedwithin a framework of teaching. We see inAristotle, who stands at the beginning of thistradition, a justification of the empirical methodof observation,'8 novel among the Greeks. But wealso see the force of traditional ideas, and thisseems to be the basic reason why Aristotle claimedthe heart as the primary organ of the body. It wascentral, mobile, and hot, and well supplied withstructures which served to communicate betweenit and the rest of the body in a sensory and motorcapacity. As a single, central organ it was themost suitable as the centre of physiological pro-cesses, the seat of the soul. The soul had nutritive,generative, sensory, and motor faculties in ahierarchy like that hinted at by Philolaus and setout by Plato. Despite the suggestions in theaccounts of his predecessors about the connectionsbetween the sense organs and the brain, Aristotleand his generation remained in ignorance of thecentral nervous system, a fact which contributedto his placing the soul in the heart. It is some-times said that Aristotle claimed that the heartwas the origin of the nerves, but this rests on amisunderstanding. Blood vessels, he said, may attheir finest branches become too narrow to con-tain blood; both kinds of vessel were called poroi,a word already in use for the connections (whichhe did not consider sensitive) between the eye andthe brain, and Aristotle may have been thinkingof what we know to be nerves. On the other hand,he used the term neura, which has survived intechnical literature to mean 'nerve', to cover allfibrous structures, tendons, ligaments, and per-haps nerves as well. It was a traditional Greekidea that the movement of the limbs was causedby the fibrous structures at the joints, not by themuscles, which they called 'flesh' and regarded asa padding for the bones. Aristotle thought indeed

that the heart was the origin of these fibres, andas their root and source he pointed to fibrousstructures associated with the cardiac valves(which he did not recognise as such). There was,however, no physical continuity between thesecardiac neura and the fibres of the joints, andAristotle did not think of them as sensitivenerves.

ARISTOTLE ON THE HEARTAs for Aristotle's anatomical description of theheart and its vessels, there are two major diffi-culties. The first is his statement that large warm-blooded animals have three cavities in theheart, the smallest have only one19, and thoseanimals of middle size have two cavities. WithNehemiah Grew 'One would a little wonder, howso observing a man, should discover so many mis-takes, in so few words'.20 There is little evidenceof a traditional or mystical view that may haveinfluenced Aristotle, as Thompson suggests.2'There is, similarly, little basis anaomically forAristotle's opinion, although various attempts havebeen made by such figures as Galen, Vesalius,Huxley, and later scholars to explain it on thebasis of Aristotle's misinterpretation rather thanhis error. Galen suggested that the 'middle cavity'of the heart, as described by Aristotle, was a por-tion of the right ventricle, and Thompson is in-clined to agree.22 Ogle thinks that the middlecavity was the left ventricle, the smallest the leftauricle, and the largest the right ventricle.23The latter explanation depends upon the nature

of the cavities and the vessels with which Aristotlesaid they communicate. Broadly, this is the secondof the difficulties we meet in Aristotle's accountof the vascular system. As noted above, the inter-communication of the heart, lungs, and largeblood vessels is fundamental to the understandingof the body machinery, and problems associatedwith it were vigorously debated from beforeAristotle to the time of Harvey. Aristotle saidthat the right cavity of the heart contains the mostabundant and the hottest blood, and the left, theleast and the coldest. The relative abundance ofblood in the differcnt cavities may perhaps be ex-plained by Aristotle's method of killing his ani-mals before dissection. This was strangulation,which would leave the ve.ns and the right side ofthe heart full of dark blood and the left almostempty.24 This method has been called a genuineadvance over the more common technique of cut-ting the throat of the animal, thereby draining offa portion of the blood.25 Aristotle said the middlecavity contained a medium quantity of blood,which was the purest and thinnest in the body.26

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This cavity serves as a common centre for theother two. To it are connected the air-filled aortaand arteries, while the 'great vessel', the venacava, is connected to the largest cavity. Here wehave a clue as to the origin of Aristotle's idea thatthe heart has only three cavities. The junction ofthe superior and inferior venae cavae with theheart is such that the vena cava appears to be arelatively straight vessel running the length of thebody and inosculating with the heart at one partof its circumference. This is more marked in thebodies of apes and young children, which we maysuppose were more familiar to Aristotle and hispredecessors than the adult human body. Thisapparent continuity of the vessel is doubtless thereason it was supposed even before Aristotle torun the length of the body, beginning perhaps inthe head and merely communicating with theheart on its journey; in other words, one of thetraditional fundamental pair of vessels of the body.For Aristotle the right auricle was simply thedilated junction of this vessel with the heart (muchas Galen thought of both auricles as merely ex-panded portions of the veins rather than as cham-bers of the heart), and he consciously identifiesthis apparently single vena cava with the funda-mental vessel of the traditional pair mentioned byHomer.Thus the largest cavity of the heart described by

Aristotle is identified with the right ventricle byits attachment to the vena cava, and, correspond-ingly, the middle cavity can be said to be the leftventricle as Aristotle says it communicates withthe aorta. All three cavities are said to havechannels to the lungs, but two of these are toosmall to be seen clearly, and we are left to inferthat as the obvious channel is that from the largestcavity,27 it must be the pulmonary artery. Itsbranches in the lung do not communicate withthe branches of the windpipe but nevertheless re-ceive air from them and pass it back to the heart,to both right and left cavities. Aristotle does notmake it clear whether the air returns to the rightventricle by means of the vessel already men-tioned, and in other places he says that the lungsare supplied with branches of 'the great vessel'.There is also a confused passage which seems togive the aorta as well as the vena cava some con-nection with the lungs. It has been suggested thatsuch a connection may refer to the fetal ductusarteriosus, a suggestion that may be significanttaken in conjunction with the opinion thatAristotle's direct knowledge of the human bodywas limited to fetal material.28 There is much thatis obscure in Aristotle's account, and strong evi-dence of textual corruption does not help one to

R. K. French

understand his thought.29 However, not all is con-fusion. The heart is the source of heat, and itsleft side is more associated with air than withblood. The contents of the left side are purer, andif we include the central cavity with the left, it isthe source of the aorta and hence all the arteries.All these details are shared by the HippocraticOn the Heart (De Corde). Moreover, we cangather from Aristotle that the lungs werenourished by blood either from the right side ofthe heart or direct from the vena cava, and if theformer was the case, there must have been a two-way flow of blood and air in the vessel from theright ventricle to the lung. The importance of thisin view of later ideas will be mentioned in dis-cussing On the Heart. On one important pointAristotle differs from the Hippocratic text: hemakes no mention of valves in the heart.

Aristotle's lack of precision in describing theconnections of the right ventricle with the lunghas caused considerable trouble to later commen-tators. Ogle suggests that the pulmonary arterywas taken by Aristotle to be part of the vena cava,separated from it by the right ventricle but shownto be allied by its connection to this same cavity,and also by the fact that both vessels are filledwith dark blood after death and that both havesimilar thin walls. His argument is then thatAristotle referred to both vena cava and pulmon-ary artery under the collective title 'great vessel'and the systemic arteries and pulmonary veinas 'aorta' collectively. However, as D'ArcyThompson points out, to admit this would be tolose the force of Aristotle's well-marked distinc-tion between the sinewy texture of arteries and themembranous nature of veins. Thompson thinksthat Aristotle groups the pulmonary artery andaorta as 'aorta' and the vena cava and pulmonaryvein as 'great vessel' despite, as Thompson admits,their disparate origins from opposite sides of theheart. It is notable, however, that in De Somno etVigilia (458a) Aristotle specifically speaks of thetwo vessels, aorta and vena cava; he is not includ-ing the pulmonary vessels under a collective name.If we accept this, and other criticisms of Ogle'sexplanation, we still have to admit that Aristotledid not adequately describe the pulmonary artery.One reason for this, that there was simply notraditional knowledge for Aristotle to draw on,has perhaps been overlooked. Even if we assumethat this was an area where he might be expectedto employ animal dissection to best advantage, itis now clear from what has been said that muchof his account depends on inherited information.It has also been seen that the two fundamentalvessels of the traditional accounts had surprisingly



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little connection with the heart, and even less withthe lungs, so that Aristotle had little to build onin attempting an anatomy of these two organs andtheir vessels. Another example of Aristotle's de-pendence on inherited information is his descrip-tion of a vein from the liver to the right arm,which is bled by surgeons to relieve pain from theliver. Lloyd30 calls this 'superstitious' but it is, ofcourse, a survival of the traditional accounts suchas those of Diogenes and of The Sacred Disease.31So Aristotle had no reason to know of the

vascular connections of the heart and lungs. Pro-bably from his own observations he attempted togather enough anatomical information to supplyhis physiology with a means to provide air for theheart and blood to nourish the lungs. The resultis similar to other schemes no doubt owing some-thing to his, that of On the Heart and that de-veloped by Galen. Had Aristotle noticed andunderstood the valves, as these two later authori-ties did, he would have been obliged to describethe anatomy of the vessels in greater detail. Asfor the rest of the vascular system, Aristotle des-cribes well enough the inferior vena cava and theaorta, as they are described in the more advancedof the traditional sources. In rejecting other de-tails from these sources, he mentions that one

method employed by the old anatomists was toobserve the bodies of living men 'reduced to ex-

treme attenuation',32 a method which resulted intoo great an emphasis being put on the superficialvessels. This may explain the similarity of the des-criptions of the superficial veins of the neck givenin The Sacred Disease and by Diogenes. Aristotlealso describes the jugular veins and notes thestupefying effect of compressing them in a livingman. He recalls the veins of the neck described byHomer.There are several remaining points to be noted.

In describing the two halves of the heart as

sepqrate systems, each with its own blood,33Aristotle provided a basis on which Galen's ideascould be built. This has been said34 to be hisgreatest advance over earlier accounts. Amongthe reasons that Aristotle put forward for locat-ing the origin of the veins in the heart rather thanthe liver was that the heart was single, as befitsthe source of a single system. The liver, on theother hand, appeared to have a substantial veinrunning through it (no doubt the vena porta andvena cava regarded as a single vessel) and so couldnot be the origin of the veins. The emphasis on

the singleness of the heart almost implies that theliver is double: 'For the liver and spleen wouldseem to lie half way between the single and doubleorgans. For they may be regarded either as con-

stituting each a single organ, or as a pair of organsresembling each other in character'. As Oglesays,35 it was a common ancient opinion that thespleen was the left homologue of the liver, and wecan see that this is the most convincing of a seriesof hints as to why the two fundamental vessels oftradition were the 'hepatic' and 'splenic'. Clearly,some physiological scheme, dominated by a regardfor symmetry, took the liver as the dominantorgan of the right side of the body, giving itsname to the vessels on that side.

Notes and references

1 On Egyptian medicine in general see Wilson,J. A., 'Medicine in ancient Egypt', Bulletin ofthe History of Medicine, 36, (1962) 114-123;Ghalioungui, P., Magic and Medical Science inAncient Egypt, London, 1963, and Dawson,W. R., 'Egypt's place in medical history', inScience, Medicine and History, edited by E. A.Underwood, Oxford, 1953. For medical texts, seeEbbell, B., The Papyrus Ebers, Copenhagen andLondon, 1937. On Indian medicine see Filliozat,J. La Doctrine Classique de la Medecine Indienne,Paris, 1949.

2 See Ranke, H., 'Medicine and surgery in ancientEgypt'. Bulletin of the History of Medicine,1, (1933) 237-257. The only surviving surgicaltext has been published by Breasted, J. H., TheEdwin Smith Surgical Papyrus, 2 volumes,Chicago, 1931.

3 Altschule, M. D. 'The pneuma concept of soul',J. Hist. Behav. Sci., 1, (1965) 315.

4 The whole question of dissection at Alcmaeon'stime is discussed by Lloyd, G. E. R., 'Alcmaeonand the early history of dissection', SudhoffsArchiv., 59(2), (1975) 113-147.

5 Wellmann lists 10 early Greek medical schools,distinguishing them primarily on their approachto the question of the most important organ ofthe body. Wellmann, M., 'Alkmaion von Kroton',A rcheion, 11, (1929) 156-169.

6 On Philolaus, see Diels-Kranz, Die Fragmente derVorsokratiker, Berlin, 1964. See, however, Kirk,G. S. and Raven, J. E., The Presocratic Phil-osophers, a convenient source for the presocratics,and which sums up the evidence against theauthenticity of the fragments of Philolaus.

7 The Timaeus is available in a number of editionsand translations. Two useful companions to thework are Taylor, A. E., A Commentary on Plato'sTimaeus, Oxford, 1928 and Comford, F., Plato'sCosmology, London, 1937.

8 An essential source on the entire question of theheart and vessels in Greek writers in Harris,C. R. S., The Heart and Vascular System inAncient Greek Medicine, Oxford, 1973.

9 Historia A nimalium 51 lb.10 Adams, F. (trans.) The Genuine Works of Hippo-

crates, vol. 2, London, 1849.

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R. K. French

11 Littre, E. (trans.) Oeuvres Completes d'Hippo-crate, vol. 1. Paris, 1839.

12 Chadwick, K. J., and Mann, W. (trans.) TheMedical Works of Hippocrates, Oxford, 1950.

13 Castiglioni, A., A History of Medicine, 1947,p. 136.

14 Neuberger, M., History of Medicine (trans. Play-fair, E.) vol. 1, p. 116, London, 1910.

15 The Historia Animalium was designed to give anaccount of the characteristics of animals, and DePartibus A nimalium conducts an investigationinto the causes of these features. What Aristotlehas to say on the soul is found largely in DeA nima. Aristotle's works are conveniently con-sulted in the English translation of the Oxfordedition.

16 In particular in his De Usu Partium: see theEnglish translation by May, E. T., Galen on theUsefulness of the Parts of the Body, CornellUniversity Press, 1968.

17 This has been translated by Hurlbutt, F. R., 'periKardies', Bull. Hist. Med., 7, (1939) 1104-1113.

18 See Lloyd, G. E. R., Aristotle, Cambridge, 1968.19 Historia A nimalium 496a, 513a. De Partibus

Animalium 666b.20 Quoted from Cole (1949) p. 39.21 Historia Animalium 496a 20 note 4.22 Historia Animalium 513a.23 In De Somno et Vigilia 458a, the aorta is said to

be connected not to the middle cavity but to oneof the side ventricles.

24 De Partibus Animalium 667a.

25 Wilson, L., 'Erasistratus, Galen and the"pneuma"', B.H.M. 33 (1959) 293-314.

26 See also Historia Animalium 496b.27 Aristotle says 'even the two small [cavities]' have

channels to the lungs. Historia A nimalium 496a.28 Platt, who makes the suggestion, extensively re-

stores the Greek to get an answer to the problem.Platt, A., 'Aristotle on the heart', in Studies inthe History and Method of Science, edited by C.Singer, vol. 2, Oxford, 1921.

29 The anastomosis between the vena cava and aortaapparently described by Aristotle is not dealt withhere as it seems clear it is a textual corruption.The reader is referred to the notes by Ogle andThompson for further details of the variousattempts to interpret Aristotle's statements on theheart and vessels.

30 Lloyd (1968) p. 74.31 There is a possibility that the vena azygos may

have been represented in the traditional accountsand Thompson thinks that the vein here des-cribed by Aristotle may be based on an imperfectknowledge of it.

32 Historia Animalium 511a.33 De Partibus Animalium 666b.34 Harris (1973).35 De Partibus Animalium 669b 15 note 2.

Requests for reprints to: R. K. French, PhD, Director,Wellcome Unit for the History of Medicine, Univer-sity of Cambridge, Free School Lane, Cambridge.

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