Circulation

THROUGH HIS QUEST, Harvey’s imagination had run in, and on, circles. At a certain point in his treatise he describes the moment when he had started to entertain the idea that blood might have a ‘circular motion’. Some paragraphs later, he places the idea within the context of the macrocosm. ‘Blood travels swiftly through the whole body and nourishes … all its parts, truly no otherwise than the superior luminaries, the Sun and the Moon, give life to this inferior world by their continuous circular motions.’

The raw ‘data’ perceived by Harvey’s eyes was realigned by his mind into the shape of a circle. Observing the snakes and slugs that formed part of his private menagerie, Harvey saw how they progressed inside their glass jars by ‘a circumvolutary movement, bending themselves into arcs of a circle’, through sinuous motion or undulation. Dogs were associated in his mind with the figure too, their forms in movement making ‘a picture of a circle’.

During his vivisections of animals Harvey noticed how their muscles often ‘worked by turns’ or ‘together’ to produce in the limbs of the body, ‘a circular movement’. ‘The muscles and the ligaments together’, he mused, ‘push and pull and so cause movement in a circle.’ He also discerned ‘the phenomenon of circular movement’ in the almost ‘imperceptible movements’ of the muscles themselves, which ‘are like the turning of a wheel’, tracing a ‘spiral or a circular line’.

In the seventeenth century the circle was the symbol of perfection. Man’s death, declared Donne, may end ‘one circle’ of life, yet it also opens another: ‘for immortality, and eternity is a circle too; not a circle where two points meet, but a Circle made at once; This life is a Circle, made with a Compasse, that passes from point to point; That life is a Circle stamped with a print, an endlesse, and perfect Circle … Of this Circle, the Mathematician is our great and good God.’ The phrase ‘perfect circle’ reverberates through the poetry of the period; the author George Chapman uses the adjective ‘circulare’ as a synonym for ‘perfect’.

Circular forms were considered perfect because, as George Puttenham wrote in The Art of English Poesy (1589), they have ‘no speciall place of beginning nor end,’ and so ‘beareth a similitude with God and eternitie’. What better way for the natural philosopher to celebrate God’s creation, and to bear witness that it was His handiwork, than by discovering within it endless circles and circular patterns?

Harvey was by no means the only intellectual to do so. Astronomers traced circular patterns in the skies. In 1543 Copernicus famously hypothesized that all the planets, including the earth, ‘circled’ around the sun. ‘The idea seemed absurd’, he admitted, both to common sense, and also in terms of the sensory evidence available to him; yet ‘as others before me had been permitted to assume certain circles in order to explain the motions of the stars’ he believed that he would be readily permitted to entertain his circular theory.

Kepler believed that the motion of planets had to be perfectly circular, the planets being visible symbols of God’s perfection. Yet observation seemed to suggest that the path of the celestial bodies was actually elliptical, as Kepler was eventually (and reluctantly) forced to admit. Even then, however, the German astronomer felt compelled to invent an excuse to explain the discrepancy – the planets, he declared, must be partly composed of earth, and, being made of that impure material, they could not imitate exactly the ‘beauty and nobleness of the circular form’.

William Gilbert (1544–1603) was the English pioneer of the study of magnetism. A graduate of Cambridge, president of the College of Physicians, and personal physician to Elizabeth I, Gilbert began his investigations by constructing a magnet in the shape of a globe. He chose the spherical form because it agreed ‘best with the earth’ and was ‘the most perfect’. The fruit of Gilbert’s researches was his 1600 magnum opus De Magnete (On the Magnet), in which he suggested that the lodestone was a microcosm of the earth, as it moved according to ‘the earth’s position, whereby it adjusts itself to the earth’s law’ – that is, in a ‘circular motion’. Gilbert would conclude that the earth itself was a great spherical magnet with iron at its heart.

Robert Fludd (1574–1637) was a fellow of the College of Physicians and a keen anatomist, who attended the demonstrations Harvey gave in support of his circulation theory. The pair became ‘special friends’ and intellectual allies, with Harvey citing Fludd in his lectures and writings. A gentleman-born, and an influential member of the medical establishment, Fludd was socially reputable and intellectually respected, King James himself sometimes summoning Fludd to his presence to discuss natural and mystical philosophy.

For Fludd was also a hermetic philosopher, adept in astrology and alchemy – by no means uncommon intellectual pursuits in the period (Fludd’s alchemical activities were in fact encouraged by the Privy Council which gave him a patent to produce steel in his alchemical laboratory). In the hermetic arts, which derived from the ancient occult tradition and which flourished throughout Europe in Harvey’s period, God was represented as ‘a circle whose circumference is everywhere and whose centre is nowhere’. In Utriusque cosmi, the vast and labyrinthine history of the microcosm and the macrocosm Fludd wrote in the mid-1620s (while Harvey was researching his treatise), divine circles and circular processes abound. When God first breathed his divine spirit into the air to create the world, Fludd tells us that it formed a ‘circular motion’. In imitation of that great creating ‘circle of divine wind’, the sun now moves, according to Fludd, in circular motion in the sky.

Portrait of Robert Fludd, the fifth son of Sir Thomas Fludd. On the right we see the circular sun, a symbol which features throughout his esoteric writings.

The motto of hermetic philosophers such as Fludd was ‘as it is above, so it is below’: what occurred in the heavens also happened on earth, and what was true for the macrocosm must hold for the microcosm also. In Utriusque cosmi Fludd applied these ideas to the specific question of the passage of the blood within the human body. According to him, God continually breathes spirit into the air where it forms a ‘circle of divine wind’; this wind is distributed by the sun to the earth in ‘circulatory air currents’. These currents are then taken into the microcosmic body via the lungs. From there they are drawn up into the heart, which sends them out as ‘divine aerial spirit’ within the arterial blood, to distribute invigorating spiritual life force throughout the body. The heart thus imitates the sun in its shape and workings, being ‘the sun of the microcosm’. In pulsation, it acts like the distributing sun, sending spiritualized blood and vital heat around the body. The blood flows in a broadly ‘circular’ fashion, in imitation of the fiery sun in orbit and the winds that do its bidding. The blood’s movement is also circular in the sense that its journey is endlessly repeated, just as the sun rises and sets daily.

Fludd’s ideas were common to the hermetical tradition. Here, in the frontispiece to an esoteric seventeenth-century text, we see an image of the correspondence between the cardiovascular system and the elements of the macrocosm.

Giordano Bruno, the occult philosopher burned at the stake for heresy in Rome in 1600, had argued along similar lines to Fludd. ‘Spiritual life force is effused from the heart into the whole of the body’, he declared, ‘and flows back from the latter to the heart … following the pattern of a circle.’ The Italian also speculated that ‘the blood which in the animal body moves in a circle’ does so ‘continually and most rapidly’.

Bruno arrived at these conclusions from the first principle that the circle is the figure of divinity. As man partook of the divine, his blood must perforce move in the only shape that was continual, constant and perfect. According to Bruno, the human soul, endowed with divine intelligence, actively chose the ideal form of a circular pathway for the blood within the body, just as the heavens and the weather elected to trace that shape in the firmament through their movements. The body, like the universe, was intelligent and alive.

Ideas relating to the circular movement of the blood were also current in more conventional philosophical and medical traditions. When the ancients contemplated the microcosm of their anatomy and attempted to describe the movement of their blood, they often used analogies of the circle and circulation. Plato thought that the ‘depletion and repair’ of the body’s organs by the blood was a cyclical process, its movement imitating the motion of the heavens – that is, it resembled a sort of ‘circuit’.

Plato’s student, Aristotle, was obsessed with circular patterns, perceiving the outline of that figure throughout the universe. ‘When water is transformed into air’, he wrote, outlining the meteorological ‘cycle’, ‘air into fire, and fire back into water, we say that the “coming-to-be” has completed the circle, because it reverts again to the beginning.’ This perpetual ‘coming-to-be’ was ubiquitous, for ‘all things under the heavens’, he declared, ‘are moved in a circle’. Generation in nature, the process of seed-foetus-child-adult-seed, was thus an eternal ‘cycle’ – a ‘kind of continuous regeneration’ that perpetuated the species.

Given Harvey’s propensity to see circles everywhere, and his conviction that ‘the body imitates the harmony that reigns in the celestial heavens’; and bearing in mind the anatomical, philosophical and hermetic ideas in the intellectual air around him, it may have been with sense of familiarity and even inevitability that he suddenly saw, at a certain point in his researches, the movement of the blood within the body as perfectly, divinely, circular.

Aristotle’s description of the meteorological cycle may have been especially important for Harvey, just as it had crucial for William Gilbert’s investigations into magnetism. Twenty years previously, Gilbert found an Aristotelian analogy for the globe’s ‘circular motion’ in the perpetual movement of the ‘humours of the earth, poured out through springs, and returned to its interior by gravitation’. The motion of the blood, Harvey now wrote in his treatise, ‘we may call circular, after the same manner that Aristotle sayes that the rain and the air do imitate the motion of the superiour bodies. For the earth being wet, evaporates by the heat of the Sun, and the vapours being rais’d aloft are condens’d and descend in showers and wet the ground, and by this means here are generated, likewise, tempests, and the beginnings of meteors, from the circular motion of the Sun and his approach and removal. So in all likelihood, it comes to pass in the body, that all the parts are nourished, cherished, and quickned with blood, which is warm, perfect, vaporous, full of spirit, and, that I may so say, alimentative.’ Harvey thus compares the perpetual cycle of evaporation and condensation in the macrocosm to the heart’s recurrent revivification of the exhausted venous blood.

When Harvey meditated upon the heart’s concoction of the blood, he found other analogies for it too. ‘In the parts’, he wrote, ‘the blood is refrigerated, and made as it were barren, from thence it returns to the heart, to recover its perfection, and there again by naturall heat, powerfull and vehement, it is melted, and is dispens’d again through the body, being fraught with spirits.’ In other words the liquid was ‘circulated’ in the heart, in the alchemical sense of being distilled.

The word ‘circulation’ was used by alchemists as a synonym for the distillation of a liquid for the purposes of refinement. George Ripley’s long poem Compound of Alchymy taught its readers ‘how to make / Of all thine Elements a perfect circulation’. The vessel in which alchemical distillation took place was commonly known as a ‘circulatory’, an English word coined in 1559. It is within a circulatory that Subtle, a character in Ben Jonson’s popular satirical play The Alchemist (1610), sets ‘the liquor Mars to circulation’.

In his Lumleian lectures, Harvey had explained how all the major organs ‘circulated’ liquids. ‘Just as by chemistry’, he had remarked, ‘divers Heates, vessels, furnaces draw away the phlegme, fermentate and prepare, circulate and perfect; soe Nature has devised [the organs to] act as alchemists by means of different furnaces and heats’. In his treatise on the heart, he now presented the organ as an alchemical circulatory.

In making this comparison, Harvey may have been influenced by Fludd. Just as the alchemist aimed to perfect earth’s substances, most famously endeavouring to transmute base metal into gold, so too, Fludd had claimed, did the heart perfect the impure blood by means of ‘circulation’. Alternatively, Harvey may have derived the idea from the Italian anatomist Andreas Cesalpino, a student of Colombo, who had made the same parallel in his writings on the function of the heart, which were published between 1571 and 1602.¹

Yet in truth Harvey could have taken the notion from anywhere, as it was embedded within the language in which he thought. It is surely significant that around this time, many words relating to circles, circular patterns and circulation entered everyday parlance, along with the alchemical terms such as ‘circulation’. ‘Circuit’ (‘to go or move in a circuit’) was first used in 1611; the adjective ‘circuitous’ came into being in around 1620; ‘circulator’ (i.e. ‘he who or that which circulates’) entered the language in 1607, while ‘circularity’ had been employed since the 1580s. The currents of the English language undoubtedly carried Harvey towards his theory.

Whatever his influences – conscious, or absorbed by a sort of linguistic and cultural osmosis – one thing is clear from the account Harvey now committed to paper. He had first imagined that blood ‘might’ have a circular motion and then afterwards, during trials and further mental elaborations, ‘found it true’ – the idea, the inspiration, preceded the experiments. We are a long way here from the Baconian empiricist, patiently constructing a theory from a myriad of facts, beloved of most nineteenth-(and twentieth-)century Harvey biographers. We are in fact much closer to the nineteenth-century poet, William Blake, who wrote ‘What is now proved was once only imagined.’

1 Alchemical circulatory movements continued to provide leitmotifs for the works of natural philosophers throughout the seventeenth century. At the end of the period the alchemist and astronomer Isaac Newton suggested that ‘The whole frame of Nature may be nothing but various Contextures of some certain aethereall Spirits or vapours condens’d as it were by praecipitation … and after condensation wrought into various formes, at first by the immediate hand of the Creator, and ever since by the power of Nature … for nature is a perpetual circulatory worker, generating fluids out of solids, and solids out of fluids.’