William Harvey, “The Book of Nature,” and Modern Medical Thought
Bryce K. Peterson
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Briefly, my talk will have an introduction, then we’ll talk about the history preceding Harvey, then Harvey himself, then we will talk about two other medical discoveries.
Introduction
<> This is a picture of Frog Basin in Northern Idaho, one of the more beautiful places on Earth. If you were to hike over this ridge, you would be met, not by a view of the ocean, the city, or any other prize signifying the end of the journey. Instead, you would be met, <> with a new view of more beauty, but one that differs in the details. New vistas can emerge as we are raised by the vision of those who have gone before. Giant’s shoulders are required to stand upon to climb to new heights. <>Einstein required Newton; Martin Luther King, Jr. needed Gandhi. As thorough readings of history reveal, few ideas are completely original, or outstandingly revolutionary. So it was with the introduction by William Harvey in the 17th century of the circulation of the blood. Built upon a long, solid history of medicine, and on the backs of others mining for new knowledge <>, Harvey was then able to unearth the stone, which, according to the Kenneth Franklin edition of De motu cordis, is “the most important work in the history of medicine” (Franklin, flap).
<> Occasionally, however, these new discoveries lead to conclusions that are not correct, such as with the 17th C advent of telescopes leading to the 19th C (erroneous) discovery of canals on Mars, quite the engineering feat of the intelligent Martians; similar such blunders have occurred in medicine, whether in topics as superficial as baldness or as serious as peptic ulcer disease. While the work of men and women in times past is essential for forward progress, healthy skepticism must remain for new discoveries.
While striking the balance between acceptance and skepticism when approaching new scientific findings can clearly be difficult, it is of vital importance in our approach to not only the patient, but the world. Although this is a topic being approached from a historical perspective, this talk is not intended to be a rigorous historical treatment; it is, rather, meant to be a thought piece that provokes conversation about the consideration a clinician must use when examining new information from any source, as well as remembering the human filter through which that information flows, affecting our own view of ideas, both old and new.
Ancient Medicine
<> To better understand the view that William Harvey had of medicine and the world, it is important to first briefly recall the historical context in which Harvey lived. <> As an obvious medical phenomenon the blood itself was given attention by the earliest ancestors of medical scientists. Many theories were given, but predominant in the Middle Ages was the view of Galen from the 2nd century A.D. I might recall to you that these theories relied on the Platonic ideas of physiology, where pneuma (air) was modified by different organs for the various requirements within the body. <> The liver combined air with digested food and produced the ingredients for growth and nutrition to be distributed by the venous system, while the heart utilized the arterial system to distribute heat as along with pneuma to envivify the body. The brain produced the necessities required for sensation and movement, distributed throughout the body by the nerves. <> Relying upon ingenious experimentation, Galen rejected the ancient idea that arteries contained only gaseous material. Instead, Galen held that upon diastole the arteries drew air in through pores on the skin, mixing it with blood drawn in from the veins. After being used in the body, the spent air or “sooty vapor” was then passed through the septum of the heart into the left ventricle, carried to the lungs, to be there expunged. (Magner, 90-93). Galen’s remained the principal theories for the next 13 centuries, and gained such respect that they were revered as nearly Holy Writ.
Harvey’s Predecessors
<>The Medical Renaissance of the 15th Century brought “admiration for all things Greek” (Porter,Greatest, 169). The original Greek texts were sought, clean of Arabic or Latin interpretation. 1525 brought a Galenic codex published in Greek, paving the way, along with other Greek works, for physicians and researchers of the modern natural philosophy to question the conflicts between these two.
One such critic came in the mid 16th Century; Vesalius, trained by a conservative Galenic advocate, studied anatomy and dissection. “Vesalius grew . . . critical. {His} Familiarity with human anatomy drove him to the unsettling conclusion that Galen had dissected only animals . . . no substitute for human [cadavers]. He now began to challenge the master [Galen] on points of detail” (Porter, Greatest, 179). Vesalius, in Book VI of Fabrica, explicitly denies the permeability of the heart’s septum to allow for the transfer of the sooty vapors as described in the Galenic model, thus clearly weakening the Galenic model of physiology. This work was continued by Vesalius’s successor, Realdo Colombo, in a similar fashion.
<> Colombo, a respected surgeon, took Vesalius’ post as Professor of Anatomy and Surgery at the University of Padua. He continued in the work of Vesalius in presenting questions regarding the Galenic models, but he made a very large, and very public, break with Vesalius, until their relationship became quite tainted. By pointing out Vesalius’ shortcomings, Colombo sought to bolster his own reputation. Colombo’s major work, published in 1559 was an anatomical text wherein he argued against the Galenic idea of blood and pneuma mixing in the right ventricle, his reasoning based on a logical analysis of the size of the components, namely the lungs, right ventricle, and the pulmonary artery. Instead, he presented what we now recognize as the pulmonary circulation, where the blood flows from the right side of the heart, through the pulmonary artery into the lungs and through the pulmonary vein into the left side of the heart (Magner, 190; Porter, Illustrated, 158).
<>Hieronymus Fabricius, Harvey’s mentor at the University of Padua, also made notable progress in anatomy, notably in embryology and the discovery of venous valves, which he published in 1603. He assumed that the valves’ physiological function was to retard the flow of blood so that distribution would be symmetric throughout the body, thus regulating volume instead of direction. (Porter, Greatest, 192-193).
Wm. Harvey
<> This milieu of ideas was present as William Harvey was receiving his education and training. Starting his training in medicine at Gonville & Caius College, Cambridge, Harvey received an Aristotelian education, considered quite archaic and outdated by the rest of the contemporary medical community (French, 51). He then left Cambridge for Padua, “the natural choice for an able and ambitious medical student. A Paduan degree was recognised . . .[as] it was the most famous medical school in Europe” (French, 59-60). Thus, from his Cambridge education steeped in natural philosophy and his cutting-edge medical training in Padua, Harvey was a hybrid from two different worlds. Whitteridge quotes Ent’s early translation of Harvey, where Harvey notes that his world view was clearly framed by the work of those giant’s whose shoulders he was climbing onto:
“. . . know I tread but the steps of other men who have lighted me the way, and (so farre as is fit) I make use of their notions. But in chief, of all the Ancients, I follow Aristotle; and of the later Writers, Hieronymus Fabricius ab Aquapendente, Him as my General, and this as my Guide.”
<> One of the steps that “lighted the way” for Harvey, according to Robert Boyle, was the discovery of the venous valves by his predecessor. This acted as a spark that turned him towards the search for an acceptable physiological answer to a picture murky with ancient ideas (Whitteridge,Movement, 27). He wrote:
“I do not profess either to learn or to teach anatomy from books or from the maxims of philosophers but from dissections and from the fabric of nature” (38).
As the above mentioned discoveries were presented in the medical world, Harvey, true to this statement, evidently repeated the experiments himself, using the “body” as his educator and authority, rather than relying on books written elsewhere. Though Harvey found the same experimental results with the venous valves, he came to very different conclusions. Harvey argued against the explanation of venous valves acting to prevent pooling of blood in the legs and feet, pointing out that the jugular veins’ valves are oriented in the opposite way. Harvey began to reason that the purpose might not be to “retard flow” but to create a unidirectional flow. Later experimentation was to prove his ideas correct (30).
I might recall to you that Harvey’s experimental research that led to the introduction of his theory of general circulation in 1618 was extensive and spanned nearly twenty years. <> He realized, by a logical argument he presents in chapter 9 of De motu cordis, that the heart pumps, by his conservative calculations, three and a half pounds of blood in one half of an hour, while the whole body only contains, upon inspection, four pounds (Franklin, 62). Many other experiments were conducted. <> Harvey proved the unidirectional nature of the venous valves with his famous ligature experiments by manually pushing the blood out of the vein and demonstrating that it could not be forced past a venous valve in a direction distal to the heart. <> He beautifully detailed these findings. <> He surmised a connection between the arterial and venous systems by noting a pulse remained and the veins grew when a tourniquet was placed upon an arm. By turning to “the Book of Nature” and performing his many vivisections and dissections, inspecting anatomy and noting the movement of the heart and blood vessels, Harvey came to conclusions which contradicted the Galenic model. Harvey was then able to utilize the rich array of ideas and observations that had been provided, <> offering up his own theory of general circulation which he published as De Motu Cordis, the writing served the “same purpose as modern scientific article[s]” where the world is informed of new findings and invited to test the theory (Movement, 13). His formal treatise arranges the argument into an exhaustive description of his observed data, presentation of the hypothesis in chapter eight, followed by proof by demonstration, logical arguments, and arguments e consequentia (predictions) and a posteriori (explanations of previous findings) (39).
<> However, though Harvey did present the idea of the general circulation of the blood, it is important to note that the current modern model differs in many key points from that put forward by Harvey in the 17th Century. The physiology behind Harvey’s model is quite similar to that of Aristotle: the distribution of heat throughout the body. The purpose of the heart, while including that of the actual movement of the blood throughout the body, was principally to envivify the blood, bestowing it with some essential quality which it would distribute to the tissues. In the extremities the blood would “coagulate,” and cool, requiring a return to the heart to repeat the cycle. The cause of the heart’s beat was mystical, as well, ultimately springing from the soul. (The modern model, of course, is one of distributing nutrients and other essentials to the tissues of the body and removing the wastes of the processes of life, with a chemo-electric cycle causing the beating of the heart). Harvey’s early education at Caius College is important to remember; Aristotle’s ideas were embedded deep within Harvey, and he held with the idea of the spiritual driving force within the heart and blood being the essential component of the blood and the point for its circulation, with the idea of the blood moving, “as it were, in a circle” featuring prominently as well. Hence, although Harvey put forward the modern idea of continuous circulation, it is also important to note the mystical, Aristotelian physiology he associated with it.
<> What effects did Harvey’s research have upon the world of medicine? His own practice was to suffer, as patients were frightened of new ideas then as well; but of the bigger picture the view becomes murky. Harvey’s scientific approach smacks of the new scientific method that was soon to become a driving force, but in Harvey’s case the roots are more ancient Aristotlean and Galenic in origin than a foreshadowing of “new science.” There were plenty of reactionary writings, both opponents and proponents, so we can certainly say Harvey’s work stirred scientific discussion. <> Ultimately, however, the influence of Harvey was in the attack upon Galenic physiology, not in his contribution to medical knowledge of cardiology (Conrad et. al, 338-9).
Modern Medicine’s Myopia
<> Harvey’s proposal of continuous circulation of the blood forms a fine example of scientific progress; he used the findings of those before him, examined them and, discarding those he found unworthy, kept only those he found accurate. Occasionally, the opposite can happen, and an article from the Journal of the American Medical Association in 1903 is illustrative of this point. <> Allow me to briefly digress in my introduction of this topic to discuss two interesting words. First, phalacrophiba – somewhat irrational as it is, <> the word describes the fear (known primarily by men in their twenties) of becoming bald. The second word, peladophobia, seems to describe a more logical fear,<> as it describes the fear of bald people themselves. Returning to the 1903 JAMA article entitled “Prophylaxis of baldness,” the introduction follows: <>
“If anyone had insisted 25 years ago that tuberculosis was only slightly hereditary, but distinctly communicable, they would have been laughed at. The germ theory has now become a doctrine of ever-widening scope, and we realize that many affections are directly communicable and only a few hereditary. At the present moment it seems that even for so old-fashioned an affection as baldness a complete change of opinion as regards etiology is taking place. As with tuberculosis, so it has long been noted that baldness is likely to run in families.”
<> The author goes on to cite findings that premature baldness is “practically always associated with the presence of certain bacteria” and then suggests a causative relationship, further hypothesizing that “undoubtedly the ordinary conditions of scalp hygiene among men are favorable to the development of these germs” and that the relative ischemia caused by hatbands may play a role as well, possibly by decreasing the ability to combat the microbes mentioned above.
<> As an exemplary clinician, the author’s principal concern appears to be for his patients. He counsels:
“Greater care should be taken with regard to brushes and combs, especially in families in which early baldness is the rule. The hair brush should be dipped in an antiseptic solution several times a week. Combs should be boiled regularly and frequently, and under no circumstances should members of precociously bald families use other combs or brushes than their own, or allow them to be used on them, in barber shops, unless they are assured of their sterilization beforehand. These precautions may seem a high price to pay for the prophylaxis of premature baldness, and many will prefer to take the chance of becoming bald, but some have such a horror of the affliction that they will willingly put themselves to much trouble to prevent it.”
While we are able to now, with the support of more than 100 years of scientific progress, find this line of reasoning and counsel humorous, it does offer an important point. New findings are being interpreted by people living in a world steeped with ideas, opinions, and “facts.” This is why progress must be met with skepticism. Not all of the “facts” are actually factual; certainly not all that is written is true. Personal observation of, as Harvey put it, “The Book of Nature,” should not so easily be replaced by new discoveries.
To turn to a more modern (and more medical) example, the history behind the approach to peptic ulcers is illuminating. <> First described by William Brinton in 1857, the lesion was accurately detailed along with its accompanying symptoms of pain, vomiting, and occasionally hemorrhage. Brinton’s conjectures as to etiology were quite varied and had an impressive scope, including “old age, privation fatigue mental anxiety, and intemperance” (Grob, 551). <> As time passed the consensus became an excess of acid as the primary factor, but this merely displaced the search for a cause to what was causing the acidification. Grob notes that “the absence of evidence that could relate causes to disease processes did not prove a deterrent. Physicians instead drew upon prevailing medical paradigms and external social and ideological belief systems to develop what appeared to be defensible etiological explanations” (Grob, 557). Such explanations included focal infection, leading to many extractions, appendectomies, colectomies and colostomies, although this explanation fell out of favor in the 1930s as no causative organism could be isolated; <> stress and psychic factors also featured prominently, with “shell shock” and the increasing demands of the industrialized world pointed to as evidence; racial factors were also considered, as one physician noted a relative dearth of ulcer disease in the African-American population, writing that it was due to the “slow-moving” and “easy-going [nature] . . . untouched by aspiration for culture.” (560)
Of course, our current understanding of peptic ulcer disease is not perfect; while the etiology is now attributed to infection with H. pylori or NSAID use, only a fraction of patients with these risk factors develop symptoms. <> Grob, however, points out that “medical explanations and therapies . . . do not always follow from rational scientific discovery, and conflicts between medical specialties, prevailing medical and scientific paradigms, ideological beliefs, and personal allegiances affect the manner in which diseases are interpreted and treated. . . To point this out is not in any way to denigrate biomedical science . . . it is merely to remind practitioners that it would be wise to recognize the contingent nature of etiological explanations and therapies.” (564). Although we strive to live a higher law, we must remember that physicians and scientists are, after all, human as well and subject to all of the interpretation flaws that history has shown us. By recognizing these flaws, we can be watchful for them and thus be able to provide better care for our patients.
Conclusion
<> With the benefit of three hundred years of scientific progress, the significance of Harvey’s discovery could be either exaggerated or minimized. His courage in tackling the Galenic fortress, though it had been softened by those before him, was immense; critics, on the other hand, could cite his inability to dispense with the mystical ideas of Aristotle as his downfall. Regardless, Harvey has influenced medicine by breaking the foundation of Galenic physiology as noted in his writing, “I do not profess to learn or to teach anatomy from books or from the maxims of philosophers butfrom dissections and from the fabric of nature.” As long as we, as clinicians, can also remember to interpret new ideas with a sense of transference and counter-transference towards the new research, we can look at Harvey’s great contribution as providing yet another, greater height whose new vista will beckon to the generations to come as they go forth on their own quests for truth.
Bibliography
Conrad, Lawrence, Michael Neve, Vivian Nutton, et. al. The Western Medical Tradition. Cambridge, England, Cambridge University Press, 1995.
French, Roger. William Harvey's Natural Philosophy. Cambridge, England, Cambridge University Press, 1994.
Grob, Gerald. The Rise of peptic ulcer, 1900-1950. Perspectives in Biology And Medicine2003;46(4):550-66.
Harvey, William, Gweneth Whitteridge, ed., De Motv Locali Animalivm. Cambridge, England, Cambridge University Press, 1959.
Harvey, William, Gweneth Whitteridge, ed., The Movement of the Heart & Blood. Blackwell Scientific Publications, Oxford, England, 1976.
Harvey, William, Kenneth Franklin, ed. The Circulation of the Blood and Other Writings. J.M. Dent & Sons, Ltd., London, England, 1979.
JAMA 1903;40:249 as quoted in JAMA 2003;289(4):494
Magner, Lois. A History of Medicine. New York City, New York, Marcel Dekker, Inc., 1992.
Porter, Roy. Cambridge Illustrated History of Medicine. Cambridge University Press, Cambridge, England, 2001.
Porter, Roy. The Greatest Benefit of Mankind. Harper Collins Publishers, Ltd., NYC, USA, 1997.
Whitteridge, Gweneth. William Harvey and the Circulation of the Blood. MacDonald, London, England, 1971.
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