On the Motion of the Heart and Blood in Animals

A New Edition of William Harvey's Exercitatio anatomica de motu cordis et sanguinis in animalibus

Harvey, Carty

• Publisher: Resource Publications
• Year: 2016
• ISBN:
  9781498235099
• Topic: Biological Sciences
• Subtopic: Science General
• Index: Biological Sciences

William Harvey's On the Motion of the Heart and Blood in Animals is a classic work of the scientific revolution and of modern medicine, for in it he famously argued, with extensive evidence based on dissections and vivisections, for the circulation of the blood. It also overturned the longstanding theories of the heart's movement and function. This new edition is suitable for classroom use and for general interest. In addition to an updated translation, it also contains an introductory essay and footnotes.

Chapter One

The Author’s Motives for Writing

When I first turned my attention to vivisections as a means of discovering the motions and functions of the heart, and sought to discover these from actual inspection and not from the writings of others, I found the task so truly arduous, so full of difficulties, that I was almost tempted to think, with Fracastorius,16 that the motion of the heart was only to be comprehended by God. For I could not perceive at first when the systole and when the diastole took place, nor when and where dilatation and contraction occurred, since the motion is so rapid. In many animals it happens in the twinkling of an eye, coming and going like a flash of lightning, so that the systole seemed to be here, diastole there, and then everything was reversed, the motions seemingly occurring confusedly together. My mind was greatly unsettled; I did not know what I should conclude, or what to believe from others. It is no wonder that Andreas Laurentius wrote that the motion of the heart was as perplexing as the flux and reflux of Euripus had appeared to Aristotle.17

Finally, by using greater diligence and investigation every day, making frequent inspection of various animals, and collating numerous observations, I thought that I had the truth that I had so much desired about the motion and function of the heart and arteries and that I could escape from this labyrinth. From that time I have not hesitated to expose my views on these subjects, not only in private to my friends, but also in public in my anatomical lectures, after the manner of the ancient Academy.

As usual, these views pleased some, others less. Some chided me and accused me with the crime that I had dared to depart from the precepts and opinions of all anatomists. Others desired further explanations of these new ideas which they said were both worthy of consideration and might be of use. Finally, yielding to the requests of my friends that they might come to know my work, and partly moved by the envy of others who in receiving my views with closed minds and understanding them indifferently have tried to disparage me publicly, I have committed these things to the press in order that all may form an opinion both of me and my labors. I am more willing to take this step because Hieronymus Fabricius of Aquapendente, though he has accurately and learnedly described almost every one of the several parts of animals in a special work, has left the heart alone. Finally, if any benefit to this department of the republic of letters should arise from my labors, it will perhaps be held that I have not lived idly, and as the old man in the comedy says, “never was there any person of ever such well-trained habits of life, but that experience, age, and custom are always bringing him something new, or suggesting something; so much so, that what you believe you know you don’t know, and what you have fancied of first importance to you, on making trial you reject.”18

So may it now be with the motion of heart. Others, at least, starting here with the way pointed out to them, may advance under the guidance of a happier genius and proceed more fortunately and inquire more accurately.

16. Hieronymus Fracastorius (1476–1553) was an Italian physician, a professor at the University of Padua, a poet, and a polymath with expertise in several sciences, including astronomy. He was a physician to the Council of Trent and a significant contributor to early modern epidemiology.

17. The Euripus Strait is a channel in Greece between Euboea and Boeotia known for strong tidal forces.

18. Terence, Adelphi, Act V, Scene IV, in The Comedies of Terence. Henry Thomas Riley, Trans. New York: Harper and Brothers. 1874.

Chapter Two

The Motions of the Heart as Seen in the Dissection of Living Animals

In the first place, when the chest of a living animal is opened and the capsule immediately surrounding the heart19 is removed, the organ is seen alternating between motion and rest. There is a time when it moves, and a time when it is motionless.

These things are more obvious in the colder animals, such as toads, frogs, serpents, small fishes, crabs, shrimps, snails, and shellfish. They also become more distinct in warm-blooded animals, such as the dog and hog, if they are attentively observed when the heart begins to move more slowly and to die. The movements then become slower and rarer and the pauses longer, and so it is easier to perceive what the motions really are and how they are performed. In its pause, the heart is soft, flaccid, exhausted, just as it is in death.

In the motion and period in which this is accomplished, there are three principal stages:

1. The heart is erected, and rises upwards to a point, so that it strikes against the breast and the pulse is felt externally.

2. It wholly contracts, but especially on the sides so that it looks narrower, longer, and more drawn together. An extracted eel’s heart placed upon a table or in a hand shows this, but it is also seen in the hearts of all small fishes and of colder animals where the organ is more conical or elongated.

3. By grasping the heart in the hand, one can note that it feels harder during its action. This hardness is due to tension, precisely the same as when the forearm is grasped and its tendons are felt to become tense and resilient when the fingers are moved.

4. It is further observed in fishes and the colder blooded animals such as frogs, serpents, etc., that when the heart moves, it becomes paler, and when at rest it is a deeper blood-red color.

From these things it appears to me that the motion of the heart consists in a certain universal tension—both contraction in the line of its fibers and constriction in every sense. It becomes erect, hard, and smaller during its action. The motion is the same as that of muscles when they contract in the line of their sinews and fibers. Muscles in action acquire vigor and tension; when they are soft to begin, they become hard, thicken, and stand out. The heart is similar.

Therefore it is reasonable to conclude that during its action the heart becomes constricted on all sides, thicker in its walls, and smaller in its ventricles, so that it may project or expel its charge of blood. This is clear from the fourth observation in which we have seen that by squeezing out the blood, the heart becomes paler, and then when it rests, the ventricle is filled with blood as its deep red color returns. But there is no need for doubt, for if the ventricle is pierced the blood will be forcibly projected with each motion or pulsation when the heart is tense.

Therefore these things happen together or simultaneously: the tension of the heart, the pulse at its apex which is felt externally by a strike against the chest, the thickening of its walls, and the forcible expulsion of the blood it contains by the constriction of its ventricles.

Hence the very opposite of the common opinion appears to be true. It is generally believed that when the heart strikes the breast and the pulse is felt externally, the heart is dilated in its ventricles and is filled with blood. But in fact the contrary is true: when the heart contracts it is emptied. Thus the motion that is generally regarded as the heart’s diastole is in truth its systole. Similarly, the proper motion of the heart is not the diastole but the systole. It is not in the diastole that the heart grows firm and tense, but in the systole, for only then is it tense, moving, and made vigorous.

It is not at all the case that the heart only moves in the lines of its straight fibers. The great Vesalius gave this notion credibility by using a bundle of osiers20 bound in a pyramidal heap to illustrate. As the apex is drawn to the base, the sides are made to bulge out like arches, the cavities to dilate, and the ventricles to become like a cupping-glass so as to suck in the blood. But in truth, every one of the fibers constricts the heart at the same time that it becomes tense, thus thickening the walls and substance of the organ rather than enlarging its ventricles. As the fibers run from the apex to the base and draw the apex towards the base, they do not make the walls of the heart bulge out in circles, but rather the contrary. Every fiber that is circularly made tends to become straight when it contracts, and is distended laterally and thickened when it contracts. This is the case for muscle fibers in general. Also, the fibers of the heart are shortened longitudinally and distend sideways as they thicken, just as we see in the bellies of the muscles at large. To all this I add that not only are the ventricles contracted in the direction and thickening of their walls, but that those fibers or bands named “nerves” by Aristotle, which are so conspicuous in the ventricles of the larger animals and contain all the straight fibers (the walls of the heart containing only circular ones), contract simultaneously by an admirable apparatus in which all internal surfaces are brought together as if with cords so as to expel the blood with force.

Neither is the common opinion true that the heart can draw the blood into the ventricles by any dilation or motion of its own. For when it acts and becomes tense, the blood is expelled; when it relaxes and sinks together it receives the blood in a way that will soon be explained.

19. This is Harvey’s only refer...

Table of contents

• Title Page
• Illustrations
• A Note on the Text
• Acknowledgments
• An Introduction to the Text
• Letter to King Charles I
• Dedication
• Introduction
• Chapter 1: The Author’s Motives for Writing
• Chapter 2: The Motions of the Heart as Seen in the Dissection of Living Animals
• Chapter 3: The Motions in the Arteries as Seen in the Dissection of Living Animals
• Chapter 4: The Motion of the Heart and its Auricles as Seen in the Bodies of Living Animals
• Chapter 5: The Motion, Action, and Function of the Heart
• Chapter 6: 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 Percolates the Substance of the Lungs From the Right Ventricle of the Heart into the Pulmonary Veins and Left Ventricle
• Chapter 8: The Quantity of Blood Passing Through the Heart From the Veins to the Arteries and 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, Concerning the Quantity of Blood Passing from the Veins to the Arteries, Through the Circulation of the Blood, is Freed from Objections and Confirmed by Experiment
• Chapter 11: The Second Position is Demonstrated
• Chapter 12: The Second Position is Demonstrated Showing that There is a Circulation of the Blood
• Chapter 13: The Third Position is Confirmed and the Circulation of the Blood is Demonstrated By 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 That Dissection Reveals