On the Motion of the Heart and Blood in Animals (Annotated) E-Book

William Harvey

• Herausgeber: ePembaBooks
• Kategorie: Wissenschaft und neue Technologien
• Sprache: Englisch
• Veröffentlichungsjahr: 2022

Beschreibung

• This edition includes the following editor's contextual introduction: William Harvey and the study of blood circulation

First published in 1628, “On the Motion of the Heart and Blood in Animals” ( Exercitatio Anatomica de Motu Cordis et Sanguinis in Animalibus) is the best-known work of the physician William Harvey, which established the circulation of blood throughout the body.
“On the Motion of the Heart and Blood in Animals”  is a landmark in the history of physiology, with Harvey combining observations, experiments, measurements, and hypotheses in an extraordinary fashion to arrive at his doctrine. His work is a model of its kind and had an immediate and far-reaching influence on Harvey's contemporaries.
In his study, Harvey investigated the effect of ligatures on blood flow. The book also argued that blood was pumped around the body in a " double circulation", where after being returned to the heart, it is recirculated in a closed system to the lungs and back to the heart, where it is returned to the main circulation.

“On the Motion of the Heart and Blood in Animals” was originally published in Latin. It was translated into English by Robert Willis (1799-1878) and published in 1847 by the Sydenham Society.

Leseprobe

William Harvey

Table of contents

William Harvey and the study of blood circulation

ON THE MOTION OF THE HEART AND BLOOD IN ANIMALS

Dedication

Introduction

Chapter 1. The Author’s Motives For Writing

Chapter 2. On The Motions Of The Heart As Seen In The Dissection Of Living Animals

Chapter 3. Of The Motions Of The Arteries, As Seen In The Dissection Of Living Animals

Chapter 4. Of The Motion Of The Heart And Its Auricles, As Seen In The Bodies Of Living Animals

Chapter 5. Of The Motion, Action And Office Of The Heart

Chapter 6. Of The Course By Which The Blood Is Carried From The Vena Cava Into The Arteries, Or From The Right Into The Left Ventricle Of The Heart

Chapter 7. The Blood Passes Through The Substance Of The Lungs From The Right Ventricle Of The Heart Into The Pulmonary Veins And Left Ventricle

Chapter 8. Of The Quantity Of Blood Passing Through The Heart From The Veins To The Arteries; And Of The Circular Motion Of The Blood

Chapter 9. That There Is A Circulation Of The Blood Is Confirmed From The First Proposition

Chapter 10. The First Position: Of The Quantity Of Blood Passing From The Veins To The Arteries. And That There Is A Circuit Of The Blood, Freed From Objections, And Farther Confirmed By Experiment

Chapter 11. The Second Position Is Demonstrated

Chapter 12. That There Is A Circulation Of The Blood Is Shown From The Second Position Demonstrated

Chapter 13. The Third Position Is Confirmed: And The Circulation Of The Blood Is Demonstrated From It

Chapter 14. Conclusion Of The Demonstration Of The Circulation

Chapter 15. The Circulation Of The Blood Is Further Confirmed By Probable Reasons

Chapter 16. The Circulation Of The Blood Is Further Proved From Certain Consequences

Chapter 17. The Motion And Circulation Of The Blood Are Confirmed From The Particulars Apparent In The Structure Of The Heart, And From Those Things Which Dissection Unfolds

Notes

William Harvey and the study of blood circulation

William Harvey was born in Folkestone, southeast London, in 1578. He was the eldest of 7 children in a family of merchants and landowners. He studied at the Bachelor of Arts at Caius College, Cambridge, and medicine at the University of Padua. His marriage to Elizabeth, daughter of Lancelot Browne, paved the way for his career, as he himself was a physician to the royal court. In rapid succession he held various positions among the most eminent. He was one of the most renowned physicians of his time, and the personal physician to James I and then Charles I, until Cromwell's revolution beheaded the latter. Harvey was left in peace.

In an era that was buzzing with ideas and where the authority of Galen, 1400 years after his existence, was beginning to crumble, Harvey had the brilliant intuition to understand that blood circulated. Already Cesalpino had coined the term "circulation" when referring to blood, but it was Harvey who unequivocally demonstrated its existence. By compressing arteries and veins of the forearm with a tight ligature, the part distal to the forearm paled. But if he loosened the pressure a little, the blood circulated through the arteries, but the ligated limb became congested, because the return through the veins was still impeded. This implied that the blood passed from arteries to veins. In order to better understand cardiac physiology and blood circulation, and taking into account that in warm-blooded animals the movement of the heart is very fast, he developed his studies in cold-blooded animals (toads, fish, snakes) or in dogs exsanguinated almost to death, in order to have enough time to observe, measure and think.

If, as Galen said, blood was continuously formed in the liver from food, and carried through the veins to all organs to feed them, a simple calculation was enough for Harvey to demonstrate the error: considering that in each beat the heart expelled 2 ounces (just over 56 grams) of blood, 72 beats per minute and 60 minutes in an hour led to consider 8,640 ounces expelled in that period: an inconceivable amount of 540 pounds, in our system 245 kilograms! It was impossible for that amount of blood to be generated, the blood had to circulate. And it was the heart that functioned as a pump, propelling the blood to the periphery, and receiving it on its return from the periphery. In this system, the venous valves that Fabrizio had described took on another meaning: they were no longer airlocks that caused the blood to stop at regular intervals to ensure the nourishment of every part of the body: they were impediments to prevent the blood from refluxing instead of returning to the heart.

"On the Motion of the Heart and Blood in Animals", a work that developed his findings, appeared in 1628. And believe it or not, the Galenists did not give up. They claimed that Harvey's calculations were not sufficient reason that perhaps not all the blood formed in the liver reached the heart, or that the heat generated by the beating heart caused the blood to become frothier and expand, so that not so much blood was formed. One explanation contradicted the next, the Galenist arguments refuting each other.

However, Harvey also failed to find the ultimate reason for the circulation, nor its meaning. Not being clear about what was going on in the lungs, lacking a theory of respiration, his physiology had to resort, like Galen's, to the spirits. This thinking torn between the rational and the magical also manifested itself in some of his other activities. Harvey was one of those charged by King James I with detecting the true witches among those accused of being witches, and some documents reflect him in this task. We can understand that he was rational as far as he could be, more so than most of his contemporaries, but unable to completely escape the environment that surrounded him.

Harvey spent his last years afflicted by gout, which caused him such intense pain that even suicide attempts are mentioned. He died in 1657. His conceptual revolution was completed when Malpighi discovered the capillaries, the proof of the link between arteries and veins, and many of the questions he generated and did not answer ( why did the blood pass through the lungs and where was it formed, what was the function of the liver, what was the purpose of circulation?) were answered in the following decades.

The Editor, P.C. 2022

ON THE MOTION OF THE HEART AND BLOOD IN ANIMALS

William Harvey

Dedication

TO HIS VERY DEAR FRIEND, DOCTOR ARGENT, THE EXCELLENT AND ACCOMPLISHED PRESIDENT OF THE ROYAL COLLEGE OF PHYSICIANS, AND TO OTHER LEARNED PHYSICIANS, HIS MOST ESTEEMED COLLEAGUES.

I have already and repeatedly presented you, my learned friends, with my new views of the motion and function of the heart, in my anatomical lectures; but having now for more than nine years confirmed these views by multiplied demonstrations in your presence, illustrated them by arguments, and freed them from the objections of the most learned and skilful anatomists, I at length yield to the requests, I might say entreaties, of many, and here present them for general consideration in this treatise.

Were not the work indeed presented through you, my learned friends, I should scarce hope that it could come out scatheless and complete; for you have in general been the faithful witnesses of almost all the instances from which I have either collected the truth or confuted error. You have seen my dissections, and at my demonstrations of all that I maintain to be objects of sense, you have been accustomed to stand by and bear me out with your testimony. And as this book alone declares the blood to course and revolve by a new route, very different from the ancient and beaten pathway trodden for so many ages, and illustrated by such a host of learned and distinguished men, I was greatly afraid lest I might be charged with presumption did I lay my work before the public at home, or send it beyond seas for impression, unless I had first proposed the subject to you, had confirmed its conclusions by ocular demonstrations in your presence, had replied to your doubts and objections, and secured the assent and support of our distinguished President. For I was most intimately persuaded, that if I could make good my proposition before you and our College, illustrious by its numerous body of learned individuals, I had less to fear from others. I even ventured to hope that I should have the comfort of finding all that you granted me in your sheer love of truth, conceded by others who were philosophers like yourselves. True philosophers, who are only eager for truth and knowledge, never regard themselves as already so thoroughly informed, but that they welcome further information from whomsoever and from wheresoever it may come; nor are they so narrow-minded as to imagine any of the arts or sciences transmitted to us by the ancients, in such a state of forwardness or completeness, that nothing is left for the ingenuity and industry of others. On the contrary, very many maintain that all we know is still infinitely less than all that still remains unknown; nor do philosophers pin their faith to others’ precepts in such wise that they lose their liberty, and cease to give credence to the conclusions of their proper senses. Neither do they swear such fealty to their mistress Antiquity, that they openly, and in sight of all, deny and desert their friend Truth. But even as they see that the credulous and vain are disposed at the first blush to accept and believe everything that is proposed to them, so do they observe that the dull and unintellectual are indisposed to see what lies before their eyes, and even deny the light of the noonday sun. They teach us in our course of philosophy to sedulously avoid the fables of the poets and the fancies of the vulgar, as the false conclusions of the sceptics. And then the studious and good and true, never suffer their minds to be warped by the passions of hatred and envy, which unfit men duly to weigh the arguments that are advanced in behalf of truth, or to appreciate the proposition that is even fairly demonstrated. Neither do they think it unworthy of them to change their opinion if truth and undoubted demonstration require them to do so. They do not esteem it discreditable to desert error, though sanctioned by the highest antiquity, for they know full well that to err, to be deceived, is human; that many things are discovered by accident and that many may be learned indifferently from any quarter, by an old man from a youth, by a person of understanding from one of inferior capacity.

My dear colleagues, I had no purpose to swell this treatise into a large volume by quoting the names and writings of anatomists, or to make a parade of the strength of my memory, the extent of my reading, and the amount of my pains; because I profess both to learn and to teach anatomy, not from books but from dissections; not from the positions of philosophers but from the fabric of nature; and then because I do not think it right or proper to strive to take from the ancients any honor that is their due, nor yet to dispute with the moderns, and enter into controversy with those who have excelled in anatomy and been my teachers. I would not charge with wilful falsehood any one who was sincerely anxious for truth, nor lay it to any one’s door as a crime that he had fallen into error. I avow myself the partisan of truth alone; and I can indeed say that I have used all my endeavours, bestowed all my pains on an attempt to produce something that should be agreeable to the good, profitable to the learned, and useful to letters.

Farewell, most worthy Doctors, And think kindly of your Anatomist,

WILLIAM HARVEY.

Introduction

As we are about to discuss the motion, action, and use of the heart and arteries, it is imperative on us first to state what has been thought of these things by others in their writings, and what has been held by the vulgar and by tradition, in order that what is true may be confirmed, and what is false set right by dissection, multiplied experience, and accurate observation.

Almost all anatomists, physicians, and philosophers up to the present time have supposed, with Galen, that the object of the pulse was the same as that of respiration, and only differed in one particular, this being conceived to depend on the animal, the respiration on the vital faculty; the two, in all other respects, whether with reference to purpose or to motion, comporting themselves alike. Whence it is affirmed, as by Hieronymus Fabricius of Aquapendente, in his book on “Respiration,” which has lately appeared, that as the pulsation of the heart and arteries does not suffice for the ventilation and refrigeration of the blood, therefore were the lungs fashioned to surround the heart. From this it appears that whatever has hitherto been said upon the systole and diastole, or on the motion of the heart and arteries, has been said with especial reference to the lungs.