The Human Heart, from Harvey to Hobbes

For two millennia the heart was considered to be the seat of intelligence, motion and sensation. Thomas Hobbes’s friend William Harvey revolutionised the understanding of the heart by demonstrating how blood circulates, and correctly identifying the function of the heart as propulsion. Soon after the publication of De Motu Cordis, Descartes redefined the heart as a ‘pump’, and Hobbes as a ‘spring’. In these mechanistic and rationalist systems the heart lost its prestige, and could no longer be considered the source of sensation and emotion. Harvey did not, however, seek to displace the heart from its traditional position in metaphysical anatomy, but by retaining an Aristotelean interest in causes, continued to promote the centrality of the heart in ways that have persisted in philosophy, theology and literature even to the present day. A fresh look at Harvey’s writings will help us to understand why.

Replicação de uma Experiência Histórica em Anatomia Humana: o papel da experiência de William Harvey a favor do movimento circular do sangue

ResumoA replicação de experiências históricas, isto é, experiências realizadas por cientistas de outrora e que constituíram marcos relevantes na história de uma descoberta científica é uma possível via para a integração da História da Ciência na promoção da Educação em Ciências. É um exemplo de uma experiência histórica aquela que foi desenvolvida por William Harvey (1578-1657), médico inglês, com o intuito de compreender o movimento do sangue no corpo humano e que se encontra descrita na obra Exercitatio Anatomica de Motu Cordis et Sanguinis in Animalibus de 1628 (Estudo anatómico sobre o movimento do coração e do sangue nos animais, Caderno de Tradução, no 5 DF/USP, 1999, tradução de Regina Rebollo). A partir desta descrição, construiu-se um protocolo orientador da replicação desta experiência e que, em articulação com outras fontes de caráter histórico, corporizou uma intervenção pedagógica para a abordagem da temática Sistema Circulatório Humano. Foi desenvolvida no âmbito da disciplina de Anatomia Humana da Licenciatura em Biologia Humana na Universidade Federal do Recôncavo da Bahia, tendo envolvido 22 alunos. Efetua-se a descrição e fundamentação da replicação da experiência histórica e analisa-se o valor educativo conferido pelos alunos a esta atividade de aprendizagem. A compreensão de como o conhecimento é construído e o desenvolvimento da capacidade de analisar criticamente perspetivas científicas anteriores são alguns dos contributos educativos apontados pelos alunos. Palavras-chave: Experiência histórica, William Harvey, Circulação sanguínea humana Abstract The replication of historical experiences, that is, experiments carried out by scientists of the past and which have been relevant milestones in the history of a scientific discovery, is a possible way to integrate the History of Science in the promotion of Science Education. It is an example of a historical experience that was developed by William Harvey (1578-1657), english physician, with the intention of understanding the movement of blood in the human body and described in the work from 1628 Exercitatio Anatomica de Motu Cordis et Sanguinis in Animalibus (Estudo anatômico sobre o movimento do coração e do sangue nos animais, Caderno de Tradução, no 5 DF/USP, 1999, translated by Regina Rebollo). Based on this description, a protocol was developed to guide the replication of this experience and, in articulation with other sources of historical character, embodied a pedagogical intervention to approach the Human Circulatory System. It was developed within the Human Anatomy discipline in Pre-service Biological Sciences Teacher Education at the Federal University of the Recôncavo of Bahia, involving 22 students. We describe and substantiate the replication of historical experience and analyze the educational value conferred by students to this learning activity. The understanding of how knowledge is constructed and the development of the capacity to critically analyze previous scientific perspectives are some of the educational contributions pointed out by the students. Keywords: Historical experience, William Harvey, Human blood circulation

The Relationship between Blood Circulation and Exercise Headache before and after the Publication of De Motu Cordis (1628): Comparison between the Scientific Thought of Girolamo Mercuriale (1530–1606) and Bernardino Ramazzini (1633–1714)

The relationship between physical activity, sports and headache is a topic of growing interest as testified by a variety of recently published papers. This correlation dates back to the Classical Age. The aim of this study is to understand how the concept of headache of vascular origin has evolved after the publication of the book De motu cordis by William Harvey (1578–1657). We analyzed and compared the books De arte gymnastica written by Girolamo Mercuriale (1601 edition) and De Morbis Artificum Diatriba written by Bernardino Ramazzini (1713 edition) focusing our attention on headache in the sportsman. By studying the De morbis artificum diatriba, it is clear that its description of the etiopathogenesis of exercise headache of cardiovascular origin is much more complete and precise than the one provided in De arte gymnastica. The limits of scientific knowledge of his time put Mercuriale at disadvantage, since cardiovascular physiology was not elucidated until 1628 with the publication of De motu cordis.

Mysteries of the Heart

The paper is dedicated to the discovery of mechanisms of circulation and the circulatory system, which was one of the greatest achievements in medicine and physiology. Without this discovery, many medical methods and technologies would have never entered our lives. In 1628, a book Exercitatio Anatomica de Motu Cordis et Sanguinis in Animalibus by William Harvey was published in Frankfurt. It was a breakthrough in scientific understanding of the functioning of heart in those days. Its author went down the history of science.

Η ιστορία της καρδιολογίας από την αρχαιότητα μέχρι σήμερα

Στους πρωτόγονους πολιτισμούς η καρδιά θεωρείτο ως πηγή θερμότητας και υπήρχε η αντίληψη ότι τα αγγεία του αίματος μεταφέρουν το πνεύμα. Χίλια τριακόσια χρόνια μετά από τις θεωρίες του Γαληνού (131-201), ο Andreas Vesalius (1514-1564) αναθεωρεί την ανατομία και παρατηρεί τα στεφανιαία αγγεία της καρδιάς. Το 1616, ο William Harvey (1578-1657) διακηρύσσει ότι το αίμα κυκλοφορεί με τη δύναμη της καρδιάς. Ο William Harvey δημοσίευσε το “Exercitatio anatomica de motu cordis et sanguinis in animalibus” το 1628, αναθεωρώντας παρωχημένες αντιλήψεις. Ο Harvey στο συμπέρασμα υποστηρίζει ότι η παλλόμενη καρδιά, είναι υπεύθυνη για τις σφύξεις των αρτηριών και όχι το “φυσικά παλλόμενο θαύμα” των αιμοφόρων αγγείων. Και το κυριότερο, ο Harvey με πειράματα έδειξε ότι το αίμα αντί να απορροφάται αμέσως, εισρέει σε συνεχή κύκλωμα μέσω της καρδιάς, των πνευμόνων, και του σώματος. Αν και η ακρόαση του θώρακα εφαρμόστηκε από τον Ιπποκράτη χρειάστηκαν 1400 χρόνια για να χρησιμοποιηθεί ξύλινο στηθοσκόπιο. Η καταγραφή του σφυγμού και η μέτρηση της πίεσης του αίματος είναι επιτεύγματα του 19ου αιώνα. Με την πάροδο των χρόνων διαγιγνώσκονται οι αρρυθμίες και συσχετίζονται οι φυσιολογικοί με τους παθολογικούς καρδιακούς ήχους. Η τεχνολογία βρίσκεται στην υπηρεσία της καρδιολογίας, όταν το βραβείο Νόμπελ απονέμεται στον William Einthoven (1860-1927) για την ανακάλυψη του ηλεκτροκαρδιογράφου. Από το 1920, το ηλεκτροκαρδιογράφημα αποτελεί την απαραίτητη επιβεβαίωση της διάγνωσης της ισχαιμίας του μυοκαρδίου ή του εμφράγματος. Το 1967, η χειρουργική αορτοστεφανιαία παράκαμψη και 10 χρόνια αργότερα, η αγγειοπλαστική βοηθούν στη λεπτομερή απεικόνιση των στεφανιαίων αγγείων. Τις δεκαετίες 1960 και 1970 η ηχοκαρδιογραφία ρίχνει φως στην καρδιά με ασφαλή και ιδιοφυή τρόπο. Οι μέθοδοι διάγνωσης και θεραπείας αποτελούν τον πυρήνα της ανάπτυξης των υποειδικοτήτων στους κόλπους τις καρδιολογίας και συνεχίζουν να εξελίσσονται μέχρι σήμερα.

Blood money: Harvey'sDe motu cordis(1628) as an exercise in accounting

William Harvey's famous quantitative argument fromDe motu cordis(1628) about the circulation of blood explained how a small amount of blood could recirculate and nourish the entire body, upending the Galenic conception of the blood's motion. This paper argues that the quantitative argument drew on the calculative and rhetorical skills of merchants, including Harvey's own brothers. Modern translations ofDe motu cordisobscure the language of accountancy that Harvey himself used. Like a merchant accounting for credits and debits, intake and output, goods and moneys, Harvey treated venous and arterial blood as essentially commensurate, quantifiable and fungible. For Harvey, the circulation (and recirculation) of blood was an arithmetical necessity. The development of Harvey's circulatory model followed shifts in the epistemic value of mercantile forms of knowledge, including accounting and arithmetic, also drawing on an Aristotelian language of reciprocity and balance that Harvey shared with mercantile advisers to the royal court. This paper places Harvey's calculations in a previously underappreciated context of economic crisis, whose debates focused largely on questions of circulation.

William Harvey and Capillaries

Circulation of the blood is so familiar that one can hardly imagine a time when it was not fully understood. Indeed, the ancients knew about the pulse and the flow of blood. They recognized, too, the vital importance of the heartbeat and nourishment. Yet the concept of a complete blood circuit emerged only in the early 1600s, largely owing to investigations by William Harvey (Figure 23.1). Harvey has since earned renown as one of biology’s great heroes. But what guided Harvey to his landmark discovery? According to many popular accounts, Harvey’s genius was reflected in his remarkable ability to deduce circulation without being able to observe the capillaries that ultimately close the circuit between arteries and veins. Moreover, Harvey’s reasoning was so powerful, they contend, that he was able to confidently predict the presence of the tiny blood vessels without ever seeing them. Only later did others confirm his insightful prediction. That triumph, tragically too late for Harvey himself to appreciate, seems to vividly demonstrate the importance of deduction and prediction in Harvey’s work—and in science generally. However, these stories do not measure up to historical evidence very well. Nonetheless, the widespread error is itself telling. Probing the erroneous stories more deeply, one can gain an even deeper appreciation of scientific myth-conceptions and how they foster misconceptions about the nature of science (essay 21). Most important to understanding Harvey’s discovery, perhaps, is his adoption of the renewed spirit of experimentation in the early 1600s: an eagerness to tinker with and actively probe nature (essay 1). Rather than read books, he dissected animals. He cut open fish, frogs, and other creatures to observe their beating hearts. His unexpected observations led him to new conclusions, which he published in 1628 in De Motu Cordis et Sanguinis, or On the Motion of the Heart and the Blood.