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The paradoxical text 'On the Heart'. II.

'(V Tfj aIae T0n tI Kpoias'-Aristotle* ERASISTRATUS AND THE VALVES Erasistratus described all four valves, 'On the Heart' describes only two. Is 'On the Heart' using the discovery which Galen emphatically attributes to Erasistratus, and to no-one else, but using it only in part? This question prompts a further one: what was the real nature of Erasistratus' discovery? References to Erasistratus on the valves are scattered throughout the corpus of Galen's works, and Galen, it is salutary to remember, was not writing history but defining his own views and defending them against rival views. Polemic is ofthe essence of Galen's mode of exposition, and in this he was a true Greek. We may at times suspect his accuracy, and in any case the removal, intact and undistorted, of a particular doctrine from among the complicated tissues of Galenic controversy is an operation which requires some care. Thus the locus classicus on Erasistratus' discovery of the valves occurs in de Placitis 6.6 (V, 549K), and the context of this passage is Galen's development and defence of his own view that not the heart, as Aristotle and Erasistratus said, but the liver is the ARCHE or starting point ofthe veins. The context is further complicated by the fact that Galen opposes his own view not only to that of Aristotle and Erasistratus but to that of certain followers of Erasistratus who appear to have 'developed' Erasistratus' views on the function of the liver in line with Aristotelian doctrine. This view, according to Galen, assumes a flow of material from the right heart down the vena cava. But this, he says, contradicts the celebrated discovery of their own master Erasistratus, for the tricuspid valve on (as both Erasistratus and Galen regarded it) the vena cava prevents any backward flow of material from the right heart into the vena cava. Thus from Galen's point of view it is the atrio-ventricular valves which are important, and more particularly the right atrio-ventricular valve; and it is the function of these that he stresses. In view of the passage cited earlier, where Galen seems to say that it was these, atrio-ventricular, valves that Herophilus described 'carelessly', and Erasistratus 'precisely', we might be disposed to argue that it was these valves which it was Erasistratus' peculiar glory to have discovered, rather than the semilunar valves. In another passage too Galen seems to stress the atrio-ventricular valves (Nat. Fac. 2, 1, II, 77K): 'not even Erasistratus wishes any other part [sc. than the lung] to be nourished from the heart, because of the implantation of the membranes (DIA TEN TON HUMENON EPIPHUSIN, i.e. the tricuspid valve which prevents any backward flow into the vena cava).' Such a possibility," should not be immediately rejected: it may be a means of discerning the true arrangement of the historical facts, if any confirmatory evidence can

Erasistatus had been a pupil of the peripatetic philosopher Strato of Lampsacus, a hard-headed mechanist who stripped the Aristotelian nature of her divine attributes and left her as a mechanical force operating 'by weights and movements'.36 In her reduced state, she looks something like the ANANKE or mechanical necessity of the atomists, but unlike ANANKE, Stratonian nature has a purpose, and Strato was a teleologist. But the similarity to Democritus serves to remind us of a mechanical strain in earlier Greek medicine, in particular as it appears in the author of the treatises 'On Generation', 'On the Nature of the Child' and 'On Diseases 4'.37 This author loves to construct models, such as the model in ch. 39 of three vessels connected at their bases with pipes so that, as fluid is poured into one vessel, the level in the others rises. This particular model represents the relation between the four main organs or reservoirs in the body which intercommunicate the humours. It is not a mere decorative tour de force, for it is evident that the author finds a real help, both in his embryology and his physiology, in such a mechanical way of visualizing processes. It is a demonstration model, to make the process clearer to the reader, but it also has a certain 3 As Abel (op. cit., p. 82) points out, this remark of Galen's, if true, shows that the valves were not generally known, ifknown at all, before Erasistratus-otherwise the slander has no point. 36 Cicero, Academica II,38,121 = Fr. 32 Wehrli. 37 Littr6, Vol. VII,pp. 470ff. and, recently edited with French tramnsation by R. Joly, in the Bud6 series. A text, translation, and commentary is being prepared by G. Baader and I. M. Lonie for the series 'Ars Medica'. On the content of the treatises see especially 0. Regenbogen, Quell. Stud. Ges. Math., 1929/30,1,131-82 and G. E. R. Lloyd, Polarity and Analogy passim. 137 c heuristic value for the author himself. The same is true of the model he uses to illustrate the process of articulation in the embyro: 'Suppose you were to tie a bladder on to the end of a pipe, and insert through the pipe earth, sand, and fine filings of lead. Now pour in water, and blow through the pipe. First of all the ingredients will be thoroughly mixed up with the water, but after you have blown for a time, the lead will move towards the lead, the sand towards the sand, and the earth towards the earth. Now allow the ingredients to dry out and examine them by cutting around the bladder: you will find that like ingredients have gone to join like. Now the seed or rather the flesh is separated into members by precisely the same process, with like going to join like'.38 But there is one feature which these two models, and the others used by the author, have in common, a feature worth considering for it gives us an insight into the development of ancient science. The apparatuses whose construction the author describes are not useful pieces of apparatus. They are gratuitous, ad hoc, serving no purpose independent of the author's own. The author thinks in terms of mechanistic processes but he does not, if the distinction is allowed, think in terms of machines-of apparatus simple or intricate, with each part in a logical relation to every other part, and all arranged in a logical hierarchy of which the particular purpose of the machine is at the summit. There is evidently mechanism and mechanism in Greek science-of mechanical process on the one hand and functional machine on the other.
Erasistratus' conception of the heart is of the latter kind: it is that of a functional machine, in which part and function cannot be separated from each other and considered in isolation.39 The four valves, the two kinds of material (blood and pneuma) are so to speak enfolded and included in the action of the heart: it is a unitary conception.
Erasistratus himself, to judge from the passage in Galen, compared the action of the heart to that of the blacksmith's bellows, which was no doubt the most familiar form of pumping device in the ancient world.40 But the heart as Erasistratus conceived it is in fact a two-stroke (i.e. combined suction-and force-) pump with double action (since it is designed to move two different fluids, blood and pneuma, simultaneously).
A pump, with two alternating sets of valves, is described by Philo of Byzantium (third or second century B.C.).41 It is a simple fire-engine pump, or the kind that used to be employed for pumping ships. In order to keep up a constant jet of water the pump has two cylinders whose intake and output alternate.
The similarity between this pump and Erasistratus' heart is that each has two sets of valves. Othetwise the differences are considerable: the heart is not a piston pump, I8 De Natura Pueri ch. 17 (VII,p. 498 Antiquity, 1963, pp. 155-57. 138 The Paradoxical Text 'On the Heart' and collapsible bellows are a better analogy to its action of diastole and systole. Moreover the pump described in Hero alternates-this indeed is its TELOS-in order to keep up a constant jet of water, whereas the heart of course sends out its material in pulses. Thirdly, the pump moves one material only, water, whereas the heart moves two, blood and pneuma. The differences are perhaps greater than the similarities. Yet both are the index of a particular way of thinking-of seeing things in terms of a definite series of events, designed to achieve a particular end. The pump in Hero, and Erasistratus' four-valved heart, recognizably come from the same world-and from the same period.42 The heart in Erasistratus is conceived as a machine: it is mechanistic, in the second of the two senses suggested above. From this point of view, it hardly matters whether Erasistratus discovered the semilunar valves as well as the atrio-ventricular valves (which as valves he certainly did discover), or whether they were known before him. If they were known before him, he 'rediscovered' them, in the sense that he brought them into his unitary conception of the action of the heart, and showed that they, along with the atrio-ventriculars, have an essential and equal role in that action. Their function cannot be considered in isolation. It is thus after all the idea of action that is predominant in Erasistratus' picture of the heart, while anatomical structure is subordinate to this idea. But the idea of action is simply Aristotle's ENERGEIA-and it is moving to see how, in Erasistratus, conception of the heart, those two strains of mechanism and teleology which Plato in the Laws (X, 889Aff.) so sharply and inimically opposed, are united at last in marriage, under the fairest auspices.
It was this anatomico-physiological conception that was the real nature of Erasistratus' discovery-the question I posed at the beginning of this section. Some or all of its elements, anatomical and physiological, may have existed before him, although probably not, as we have seen, the recognition of the atrio-ventricular valves as valves.43 But once this discovery, in this sense, had been made, was it reversible? It could certainly be rejected outright-and as we have seen, some of Erasistratus' contemporaries did so,44 as did Asclepiades later on.45 But could it be retained in part, and rejected in part? It seems unlikely: not only would such a partial acceptance make nonsense of Erasistratus' unitary conception, but it would involve the loss of a splendid opportunity for teleological moralizing-such as that in which the author of 'On the Heart' indulges. We must nevertheless entertain the possibility-for it is a curious fact that neither the Stoics nor the Stoic-influenced Pneumatic school nor the Church Fathers who echo the Stoic theme de fabrica hominis ever specifically mention the 4" Erasistratus might well have seen this pump, since it was originally invented by the practical genius Ctesibius, who probably lived in Alexandria in the reign of Ptolemy 11 (283-247) and was therefore a contemporary and fellow-citizen of Erasistratus. For the relations between Hero, Philo, and Ctesibius see now H. B. Gottschalk, Strato of Lampsacus: Some Texts (Proc. Leeds Philosophical and Literary Society, Literary and Historical Section, Vol. XI, 1965, pp. 95-82), pp. 133ff.; and A. G. Drachmann. Ktesibios, Philon and Heron, Acta Historica scientiarum naturalium et medicinalium, Vol. 4, Copenhagen, 1948. For a similar problem in connexion with William Harvey, see Walter Pagel, op. cit., pp. 212-13 and n. 14, especially with reference to C. Webster in Bull. Hist. Med., 1965, 39, pp. 508-17. " It is significant in this respect that they were first named, not by Erasistratus himself but by his successors.

139
I. M. Lonie valves. Yet they were not averse from such detail: the function of the epiglottis features prominently in Cicero's rhetorical treatment of the theme." Yet it is also probable that the Stoics and Pneumatics 'knew' of, or rather accepted, the valves and their function. For Galen, who says that most physicians of his time took them for granted, would certainly have mentioned the Pneumatic school, if they had been an exception; and acceptance by the Stoics can I think be inferred from Cicero, De Natura Deorum 2.138 with Gregory of Nyssa, De Opificio Hominis ch. 30, Patres Graeci XLIV, col.
240ff. Migne.47 Cicero says: 'nam quae spiritu in pulmones anima ducitur, ea calescit primum ipso ab spiritu, deinde contagione pulmonum, ex eaque pars redditur respirando, pars concipitur cordis parte quadam, quem ventriculum cordis appellant, cui similis alter adiunctus est, in quem sanguis a iecore per venam illam cavam influit; eoque modo ex his partibus et sanguis per venas in omne corpus diffunditur et spiritus per artus.' And Gregory of Nyssa: 'The heart is contained in the middle of the lung, and in perpetual motion, in which.it imitates the action of fire, which moves eternally, it attracts, like bellows in foundries, material from the lung placed alongside it, filling its own cavities as it dilates, and fanning what is fiery in itself, it breathes it out into the adjoining arteries. And it never ceases from doing this: in dilation, attracting from outside into its cavities, and in compression, distributing material from itself into the arteries' (op. cit. col. 245C).
What is significant in both passages if they are combined is the movement of diastole and systole (implied in Cicero, and mentioned explicitly in Gregory), by which blood on the one hand, and pneuma on the other, is alternately attracted into the heart and distributed from the heart to the body. This could hardly be visualized without the assumption of valves-which are in any case implicit in the comparison ofthe heart's action to that of bellows.
The lack of any specific mention of the valves in later sources is. odd, but we cannot assume that they were discarded, either wholly or in part, except by Asclepiades and the Methodists. Indeed the evidence, such as it is, points rather in the opposite direction. We may assume that Erasistratus' 'discovery', in the sense defined above, remained unreversed.
The conception of 'On the Heart', where there are only two valves, and no 'action' of diastole and systole, is quite different from that of Erasistratus. But it must be admitted that the details of its physiology are quite indistinct and uncertain. Although there is no account such as Erasistratus gave of diastole and systole, the author does speak of the heart as 'leaping' (chapters 1 and 8), and gives a striking observation of the difference in movement between the 'ears' and the heart as a whole: 'you can see the heart jumping as a whole, while the ears inflate and collapse with a movement of their own' (ch. 8). Significant too is the description of the heart as 'a very strong muscle' (ch. 4). What the function of its musculature is we are not told. Evidently it has nothing to do with the passage of air between the heart and the lungs, in which the author is primarily interested, for it is the 'ears' which 'handle' (KHEIROUTAI) the 4" De Natura Deorum 2.163: probably from Posidonius, who was interested in the epiglottis from this point ofview: cf. Scholiast on Homer, 11.22.325 and Reinhardt, RE XXII, 1,708ff.
The Paradoxical Text 'On the Heart' breathing from the lung into the heart (ch. 8). But the question of the heart's musculature and its function involves a cluster ofproblems.
According to the interpretation of the anatomy in ch. 7 given previously, the 'ears' whose partial removal exposes the four orifices must include the atria as well as the auricles proper. Hence the author can describe them as 'cavernous' (SERANGODEA) and can compare them to the blacksmith's bellows. The right atrium is also regarded as the terminal section of the vena cava, and presumably, by an obvious analogy, the left atrium of the pulmonary veins.
This was the view shared by Galen with Erasistratus, whose view of the relation between the auricles and the heart was contrary to that of Herophilus: 'If anyone, like Herophilus, regards [the auricles] as part of the heart, he has increased the number of the orifices, and in this he will appear to be at variance with Erasistratus and myself, who have said that there are four orifices in all' (Galen II 624K; cf. Wellmann RE s.v. Erasistratus 340, 68). The number of orifices would be increased because the vena cava would then be regarded as having two orifices, with four for the pulmonary veins, which Galen regards as one.48 This supposition is part of the standard, 'classical', picture of the heart with its two chambers and four orifices (there is, says Galen de Placitis 6.6 (V, 551K) no 'fifth opening'), which can thus be brought back to Erasistratus-and is found in 'On the Heart'.
In the De Usu Partium 6.15 (III, 481 K) Galen has something to say of the function of the atria regarded as part of the vessels: 'It seems to me that when the heart exerts its full powers of attraction, it would actually tear a vessel to pieces if our Creator had not in this instance too contrived a protection against such an accident by placing outside each opening that admits material another separate cavity like a storehouse for nutriment, so that the vessel may not be in danger of rupturing when at times the heart attracts suddenly and violently and the vessel alone, because it is so narrow, cannot furnish abundantly all that the heart demands ... Thus the auricles of the heart were not formed in vain, though no good sense was used in naming them. . .' (trans. May,. We have of course no reason to suppose that this was also Erasistratus' explanation, although it would be quite in accordance with his views. But it does help to bring into focus a problem both in the text of 'On the Heart' ch. 8, and in the physiology of the treatise. The received text reads '(the craftsman) seeing that the organ would be a solid thing, owing to the density [?] of its material [text uncertain], and in consequence entirely attractive, equipped it with bellows, as blacksmiths do their furnaces, by means of which to control [or 'manage'] its respiration'. Unger changed the reading, by supplying a negative, to 'and in consequence not at all attractive'. His reason for doing so is in the following chapter, where it is what is 'soft' or 'yielding' (MALA- KON), not what is hard or solid, that has the greater attractive power-this is the reason, says the author, why the left heart breathes through veins, instead of through an artery like the right heart. Unger's change has much to recommend it. Without it, there is a contradiction between the two chapters, and the transitional phrase at the *8 Cf. De Usu Partium 6.7 (III, 436K) and May, p. 292, n. 28; de Placitis 6.6 (V, 548), where Erasistratus is represented as speaking of the (one) orifice of the (one)  141 beginning of ch. 9, 'for this reason' (DIA TOUTO), loses its significance. Yet Galen's 'powerfully attractive heart', to whose force the atria serve as moderators, does tempt us to leave the text as it stands, with a query against it. The purpose of the auricles in 'On the Heart' would then be to control the draught rather than to create it; and to describe the heart as 'entirely attractive' would give some purpose to its powerful musculature, which at present it lacks. What does the heart do with its muscles? It provides blood for the lung, we are told, and this is presumably by pumping-but does it attract blood, or at least potentially sanguineous material, from the vena cava? And does it, from the left ventricle, send out that luminous substance to the rest of the body? Presumably it does, since it is equipped with a unidirectional valve on the aorta. We begin to suspect that the author has left half the story untold-which is not the same as saying that he has told all he knows. It is the same situation as we have found several times before: clear and surprisingly sophisticated detail on the one hand, suggesting a well-developed background of anatomy and physiology, and an elusive vagueness on the other-like, perhaps, a badly remembered lesson. In points of detail there is both agreement and disagreement with Erasistratus. Unlike Erasistratus, he regards the arteries as containing blood, and he situates the intellect in the heart, whereas Erasistratus located it in the membranes of the brain. On the other hand, the reason he gives that the left heart is fed from the lung through veins, because of their greater attractive power, implies the principle 'horror vacui' (PROS TO KENOUMENON AKOLOUTHIA) ofwhich Erasistratus made such systematic use. 49 The point on which the author of 'On the Heart' most obviously deviates from Erasistratus is his insistence that ingested fluid, or a portion thereof, passes into the lung, a belief which he demonstrates by slaughtering a thirsty pig who has been given dyed water to drink (ch. 2). The view that the trachea is the normal passage, and the lung the normal receptacle, for all fluids, was held by Philistion and subsequently to, and perhaps in dependence upon, Philistion, by Plato.Y0 The function ofthe fluid which reaches the lung in this way is to cool the heat of the heart.
The view that is represented in 'On the Heart' differs significantly from the view stated by Plato. While in Plato all the fluid swallowed passes down the trachea into the lungs-the passage in Timaeus, 91A leaves no doubt about this-in 'On the Heart' it is only a portion, and that a very small one, which passes down the trachea. The reason given is the 'precise fit' of the epiglottis. Moreover, although the author retains the cooling function of this liquid, it does not cool by remaining in the lungs but by being filtered out and gathering round the heart itself, inside the pericardium, as the pericardial fluid. We cannot then equate tout court, as has sometimes been done, the view of 'On the Heart' and of Plato, and regard both as the view of the Sicilian school ofmedicine.
"@ There is even perhaps a coincidence in vocabulary: the word DEXAMENE, properly meaning a tank or cistern, is used by the author of 'On the Heart' to refer to the right ventricle. It was evidently used in reference to the heart by Erasistratus, in the passage quoted above from Galen, De Placitis: "'the heart" says Erasistratus "is no lifeless receptacle (DEXAMENE)"'. Galen himself may be echoing Erasistratus in another passage, De Usu Part. 6. 11 (III, 461K), where he describes the right chamber of the heart as a DEXAMENE. This is a frail point of course; but the word is not particularly common. It was used however by Democritus-of the blood vessels (B135). ' For Philistion, see Plutarch, Quaest. Conviv. 7. 1, 699A; for Plato, see Timaeus 70C; 91A; and in general F. Kudlien, Der Beginn des medizinischen Deukens be!den Griechen, 1967, p. 88ff.

142
The Paradoxical Text 'On the Heart' The view as it appears in Plato was disputed both before and after Plato's time. It was disputed before Plato," in Diseases 4 ch. 56, where the author proudly enumerates seven arguments from observation (HISTORIA) against the view (and then adds another one for luck); and after Plato by Aristotle ('On the Parts of Animals' 3.3, 664B3ff.) and by Erasistratus (whose arguments are recorded in Plutarch op. cit.). Some of the arguments used in Diseases 4 reappear in a recognizable form, both in Aristotle and in Erasistratus. One of these arguments is the function of the epiglottis, which has evidently not yet acquired its name in Diseases 4 (nor, in fact, anywhere in the Hippocratic Collection apart from 'On the Heart'), where it is described as '(a covering) like a leaf of ivy', but which is named in Aristotle. Aristotle gives an accurate description of the epiglottis and its function, and as one might expect, it is for him a valuable illustration of the purposiveness of nature (as it was to become for the Stoics: see above). Now the recognition of the existence and function of the epiglottis was not decisive against Plato's view, or at least a modified version of that view, for it was defended by Dexippus 'the Hippocratic' as Plutarch op. cit. calls him,52 who recognized the epiglottis, but reformulated the theory and stated that only a small portion of liquid enters the lung. Dexippus' words as reported by Plutarch have a curious resemblance to those of 'On the Heart'. The function of the epiglottis is 'to filter through the drink gently and in small quantities so that it does not force back and disturb the breath by rushing in in a mass' (Cf. 'On the Heart', ch. 2: 'Since the liquid flows through the crevice in small quantities it does not obstruct the ascent of the air'). It also performs, as in 'On the Heart', the service of moistening the trachea.
It is this reformulated view, depending upon the recognition of the epiglottis, which we have in 'On the Heart', and to it, the author has added the demonstration with the pig, not mentioned in Plutarch. To claim that it is post-Platonic is not to stretch the evidence beyond toleration, for surely Plato (or his source) would not have disregarded the opportunities, exploited by Aristotle and the Stoics, for making a teleological point of the epiglottis. Indeed, according to Plutarch, Erasistratus criticized him sharply for this omission, one altogether inappropriate in a philosopher who 'sought after the final cause of each part of the body'. The formulation given by Dexippus-and used in 'On the Heart'-shows how this might be done without sacrificing the essence of the view that liquids pass into the lung.
Once again, the evidence points to a degree of relatively late development in 'On the Heart'-and once again, it serves to detach the author from any historically identifiable personality or doctrine. For Erasistratus, who knew about the epiglottis, did not himself adopt the modified view of Dexippus-he is rather opposed by Plutarch to Dexippus.
By adopting this modified, and therefore later, view, the author of 'On the Heart' gets, so to speak, two 'final causes' for the price of one. This brings us to the question of-Teleology.
The most striking single feature of 'On the Heart' is its teleology. Not only are 61 I ask indulgence for the assumption that 'Diseases 4' is pre-Platonic or at least pre-Timaeus, although I think this will be readily granted. "The name in Plutarch is Dioxippus: for the identification with Dexippus see Wellmann in RE V, 294.
143 I. M. Lonie particular details in the anatomy of the heart provided with a functional53 explanation, but the whole structure of the work is designed to lead up to the explanation of the working of the semilunar valves which, as we shall see, the author regards as 'a masterpiece of Nature's craftsmanship'. The treatise, in structure, is a pietistic sermon on such craftsmanship as it is revealed in the workings of the heart. But perhaps more significant than this is the degree to which the author has absorbed a functional approach to anatomy and physiology-the extent to which he takes such functional (and, in the context of Greek science, teleological) explanations for granted. Thus in his discussion of the pulmonary artery and the pulmonary veins he assumes that an observed anatomical difference requires an explanation in terms of function-an assumption which in earlier Greek science is exceedingly rare. Teleological moralizing may be, and often is, a mere rhetorical flourish; but a functional, and teleological approach of the order which we have here is no mere adventitious decoration which might be learned overnight.
In ch. 1. the pericardial fluid exists 'for this purpose, that the heart might leap in safety (TOUTOU HENEKA, HOKOS ... .)'. This resembles Plato's Timaeus, where the fluid-filled lung is both a cushion for the heart to bounce against, and a cooling system for the heart: a further function which the author goes on to apply to the pericardial fluid. The fluid, he says, resembles urine, 'so that you would think the heart was moving in a bladder', and he goes on to describe the heart-it has an odd sound-as'lapping up'the fluid from the lung and 'urinating it out'." Thus the Platonic functions are retained, but the anatomy is different. We remember that Aristotle criticized Plato for describing the lung as a cushion (PA 3.6, 669Al4ff.: he does not care to mention that Plato also said that it was for cooling the heart). Perhaps the author remembered it too and ascribed this function to the pericardial fluid instead. The notion of the protection of organs is a common trait in passages of Greek science which have a teleological approach: vide the Timaeus."6 It occurs again in ' The explanation of the structure of an organ by reference to its function is not of course the same as a teleological explanation, which is anthropomorphic, explaining such structure by reference to the 'purpose' of some divinity or conscious power. Indeed, a functional explanation is logically quite compatible with a mechanistic approach to nature, and may even be an inevitable consequence of such an approach (cf. what was said above about the two senses of mechanism in Greek science). Nevertheless, it is an accident of the way in which Greek science developed, from Plato through Aristotle and the Stoics to Galen, that such functional approaches are always implicitly, and often explicitly, teleological. In Plato's Timaeus for example, while a particular explanation might, considered in isolation, be regarded as simply functional, the whole approach of the dialogue, in which everything in the visible world is a result of the craftsmanship of the DEMIOURGOS or of his ministers, can leave us in no doubt that particular explanations as well as being functional imply an anthropomorphically conceived 'purpose'. What is true of the Timaeus is also true of the whole Galenic corpus.
It is true of 'On the Heart' as well: the reference to the 'expert craftsman' in chapter 8 implies a similarly teleological approach in passages of functional explanation where such a power is not explicitly mentioned. It was of course theoretically possible, in any Greek writer, for a functional approach to divest itself of the teleological swaddling which was the legacy of Plato. But I am not aware of any case, apart from the rather doubtful one of Strato of Lampsacus, in which this was in fact done. For practical purposes, in the history of Greek science functional explanations are synonymous with teleological explanations. " See Unger's text and discussion: he retains the DIOUREEI of the manuscripts, which Littr6 after Schneder changed to DIORROI. The metaphors are rugged-a reason for retaining them. There is, perhaps, an implicit comparison to the embryo cushioned in the amniotic fluid, which was sometimes identified with urine. The strange accumulation of participles with LAPTOUSA are explained by Kudlien op. cit. p. 425 n.l . as glosses, with reference to Hesychius. He is undoubtedly right. ' SOTERIA and BOETHEIA, 'salvation' and 'succour' are key words here: cf. W. Theiler, Teleologische Naturbetrachtung, p. 75. The author uses TIMORIE in ch. 3. 144 The Paradoxical Text 'On the Heart' chapter 6, where the thick or massive construction of the left heart is 'for the purpose of protection against the strength of the hot'. The same observation, and a similar explanation, is applied by Aristotle to the middle of his three chambers, which is presumably the left ventricle."56 The care taken by nature that parts should receive neither more nor less cold and heat than is good for them is implicit in what the author says about the lung in ch. 6, which 'keeps in check the intemperance of the hot', and about the pulmonary vascular system in the three culminating chapters of the work. The function of the air is generally described as a 'service' or even 'cure' (THERAPEIA) in ch. 3.
A feature of teleological explanations are 'Technikvergleichen', parts of the body being compared, in respect of form and function together, to familiar instruments or utensils. In 'On the Heart' the gullet is like a funnel (KHONOS) (ch. 2), the left chamber is like a 'mortar' (ch. 5, HOLMOS)-or should we say, a crucible?57 And the auricles, 'the instruments (ORGANA) with which nature captures the air', are compared to the bellows on blacksmiths' furnaces. Similarly in ch. 10 the musculi papillares (evidently) are called TONOI: the word is fairly general, but seems here to mean 'guy-ropes' or 'stays'.58 Thus the short treatise is saturated in teleology: almost every chapter shows some sign of this feature. But the culmination is in chapters 10, 11 and 12-'the unseen59 membranes ofthe heart, a work of craftsmanship (ERGON) altogetherworthy ofdescription (AXIAPEGRTOTATON)'. That 'worthy of description' may make us pause for a moment. We might sense the tones of the rhetorician, elegantly embroidering upon a TOPOS or set theme. We might suspect the genuineness of his interest: is the anatomy of the heart an end in itself, or merely an occasion for rhetorical display? But the detail is against it: the thorough and personal knowledge of the anatomy of the heart. Rhetoricians do not usually care to be so specific-or to dirty their hands. Indeed, it was a reflection on dirtying one's hands in the zoology laboratory that inspired Aristotle to one of his noblest passages (On the Parts ofAnimals 1.5). Thus the rhetorical touch will be of no use to us in locating the work. But we note in AXIAPFGIETO-TATON a strand which connects the author on the one hand with Aristotle, and on the other with the more Posidonian passages of Cicero and later writers, down to the Church Fathers.
It would be a hazardous proceeding to attempt to date a work by the presence of teleology in it, and still more hazardous to posit several quite distinct varieties of 56 But in Aristotle (PA 3.4, 665B) the purpose is 'to guard the source of heat'. Possibly the corresponding passage in 'On the Heart' should be translated similarly. Yet 'strength' (ISKHUS) seems to suggest a potentially deleterious force, particularly since the author has just described the corrosive effect ofheat on the chambers. 57 Littr6 takes this to refer to the whole heart. But the author is still speaking of the left chamber and does not return to the heart as a whole until the next chapter, which begins with the words 'both (sc. chambers) are rough inside. . .' (So too Diller interprets the passage op. cit., p. 208). Besides, the author is describing the inside rather than the outside shape-the heart 'is hollowed out inside like a mortar in shape'-and a mortar does not have two compartments.
68 Used of the torsion straps of siege engines in Philo's Belopoeica. Is this an example of a 'mechanistic' approach? Cf. what was said above about Erasistratus' conception of the heart as a machine.
I. M. Lonie teleology, and allot them to different schools or persons. A teleological account de fabrica corporis humani seems to go back as far as Diogenes of Apollonia [see Theiler,op. cit.,p. 6ff.]. Then there is the famous tour de force in the Timaeus. Plato may owe it to Philistion or in general the 'Sicilian school', but it seems more likely that his procedure was to adapt medical doctrines and to give them his own expression [see G. E. R. Lloyd, Plato as a Natural Scientist, JHS 88 (1968) [78][79][80][81][82][83][84][85][86][87][88][89][90][91][92]. The teleology may quite easily be his own, and apart from the doubtful case of Diocles, we do not know of any member of the 'Sicilian school'-i.e. Philistion-who indulged in such explanations. Nevertheless, a teleological passage at any time in the fourth century would not surprise us. But the detailed and systematic character of the teleology in 'On the Heart' suggests a later rather than an earlier date-quite apart from other considerations.
The author speaks of the auricles as being the work of an 'expert craftsman' (KHEIRONAKTOS AGATHOU) who observes (KATASKEPSAMENOS) and contrives accordingly. This is obviously reminiscent of Plato's craftsman god of the Timaeus, the DBMIOURGOS. Theiler illuminatingly points out a significant difference-the result of a metaphysical development in Plato and in Aristotle-between the two philosophers in this respect. Plato's DEMIOURGOS becomes, for Aristotle, PHUSIS, nature, who as efficient cause (ARCHB KINkSEOS) and formal cause (EIDOS) combined, is in the living thing itself [Theiler, op. cit., p. 90ff.]. We find this Aristotelian conception in ch. 8, already referred to: the auricles are 'the instruments with which nature captures the air'-followed immediately by 'the work of an expert craftsman', just as on occasion Aristotle says 'nature contrives' (PHUSIS DtMIOUR-GEI PA 654B29, cf. Theiler, p. 89). Plato himself, on the other hand, had reservations about the word PHUSIS, and these reservations are expressed in his last work, The Laws." The movement seems to have been towards a more immanent conception of nature, from Aristotle to the Stoics. From this point of view, 'On the Heart' may be anywhere along that line. We should perhaps put the philosopher Strato of Lampsacus in a class of his own, since his conception of nature was remarkable for its absence of any anthropomorphic feature: it is characterized in that way by the Epicurean Velleius in Cicero's dialogue De Natura Deorum (1.35 'Strato ... qui omnem vim divinam in natura sitam esse censet, quae causas gignendi augendi minuendi habeat, sed careat omni et sensu et figura'.  Wehrli) and made use of by the Academic Cotta in the third book of that dialogue, who no doubt gives us a more accurate impression: 'Naturae ista sunt (sc. the phenomena of cosmic sympathy and harmony) ... naturae non artificiose ambulantis, ut ait Zeno, . . . sed omnia cientis et agitantis motibus et mutationibus suis' (3.27). These words of Cotta's seem far removed from the craftsman nature, PHUSIS KHEIRONAX, of 'On the Heart', which resembles " Whether such a conception is present in Diocles or not, we cannot be sure. He certainly gave a teleological explanation of the cotyledons in the uterus (Fr. 27), and Soranus, who reports him speaks of 'nature' as acting 'providentially (PRONOETIKOS)' in this. And there is also a 'Technikvergleich' in Fr. 26. The sperm adheres to the womb because ofthe roughness of the latter, just as those who glue together wood or stone rasp the surfaces first. On this see Diller, RE XIX, 2, col. 2408. Certainly Dioles was a teleologist-that is clear; there is no reason why he should not have been one of the Aristotelian "variety", if we can so call it; and if he was Aristotle's pupil, it is more than likely. This may be a reason for associating 'On the Heart' with Diocles and his circle.
The Paradoxical Text 'On the Heart' rather the Stoic 'natura artificiose ambulans' referred to by Cotta. But Erasistratus, who had been a pupil of Strato, was according to Galen never tired of extolling the 'craftsmanship' and 'providence' of nature-which he too seems to have regarded as an immanent force."' So far as the teleology of 'On the Heart' is concerned, it squares with what we are told of the teleology of Erasistratus.
The history of teleological explanation, and in particular the history of the idea of an immanent PHUSIS, are always fascinating subjects. But we should not allow them to take us too far down the centuries. It is a salutary reminder to turn back to the late fifth or early fourth century and read the famous passage in Epidemics 6.5, 1 (V, 314 Littr6): 'Natures are the physicians of diseases. Nature herself finds out the methods ... Nature is cultured: of herself, and without taking instruction, she does what is necessary.62 Compare the craftsman of 'On the Heart', who certainly might be said to 'do what is necessary'. The idea is certainly there, ready for the taking, at the end ofthe fifth century.

THE NOURISHMENT OF THE LEFT HEART
'Its nutriment' says the author of the left chamber, 'is neither the solid food nor the drink which comes from the belly, but a pure and luminous substance which is refined out of the blood. It conveys this nutriment out of the neighbouring blood receptacle by transmitting its rays, deriving it from there as though from the belly and intestines . . .' (ch. 11).
However the rest of the body is fed-the author does not tell us clearly-^the left chamber requires a special nutriment. This is as it should be-KATA PHUSIN-for the left chamber is the seat of the hot and of the intellect (GNOME).,, Hence its greater thickness and, in comparison with the right chamber, its more corroded appearance; hence too its greater need of refrigeration from the lung. What nourishes the left chamber is not blood, but a 'pure and luminous substance' arising from blood. We may call this substance pneuma, that maid of all work in Greek philosophy and science, who appears in so many and such strange disguises. Pneuma is universally regarded as the product of moisture and heat. For example, the author of 'On the Nature of the Child' expresses this in quite mechanistic terms: any organic substance, he says, which is heated will, provided that it is moist, produce pneuma, and he gives as instance leaves, green wood, legumes (ch. 12, VII, p. 486ff. Littr6). For Aristotle too pneuma, despite its ultimate mystical significance, is initially a product of mechanical processes (GA 2.6, 742A1 5): given moisture and heat, pneuma follows 'by necessity' (ANANKE, a word which indicates the mechanical explanations so characteristic of pre-Socratic philosophy-and deplored by Plato). In Diogenes of Apollonia sperm was 'pneumatic' (Simplicius, in introducing Fr. 6; DK II, p. 62, 12); it was a foam arising from blood. There is nothing surprising about *1 See my note 33 on p. 441 of Bull. Hist. Med., 1964. 1 am now convinced that not only the Erasistrateans, but Erasistratus himself, was a teleologist and that, whatever he may have learned from Strato, he 'anthropomorphized' nature.
"'The GNOME . . . which rules over the rest of the soul (PSUCHES)' ch. 10. GNOMfl = NOUS (intellect) would seem to be an early use. [In Aretaeus the Pneumatic, which is mentioned by Kudlien op. cit. 427,n. 2 (CMG 112,p. 22,26ff. H.), the word seems rather to mean, as is usual at all periods, 'powers ofjudgement'.] But ofcourse there may be conscious archaism in 'On the Heart'. 147