Part 22

Galileo's discovery of the satellites of Jupiter, the rings of Saturn, his experiments with the pendulum, his construction of the telescope, as well as of the thermometer, and many other deeds, have stamped him as one of the great figures in the history of progress and science. It is most interesting to note that this contemporary of Harvey's, like himself, was given to inductions obtained from experimental studies. Another great astronomical light of Harvey's time was Keppler, who was driven from one place to another by religious fanaticism, until he ended his life in 1630. It was he who formulated the great principle which underlies the motions of the planets, and who gave to the world his so-called "laws," which so materially advanced the science of astronomy. It was he who really discovered that comet which was later given Hailey's name, whose periodic return he first foretold.

Such was the spirit of the times in which Harvey lived, and such the influences which surrounded his teachers before him and himself in turn. It makes a long preface to a consideration of what Harvey himself accomplished, but it is not without its interest because men and their deeds must be judged largely by their environment. Now, to speak more particularly of Harvey himself, and what was known of the circulation when he undertook his investigations.

The liver had been considered, from time immemorial, as the principal factor in the production and movement of the blood. The ancients supposed that here the veins took their origin and that through them the blood flowed to all parts of the body, returning to its source by an undulating movement or series of alternate waves. The arteries had been supposed to contain only vital spirits, whose great reservoir was the heart, although Erasistratus had admitted that in certain cases blood might escape into the arterial channels. Later Galen showed that the arteries always contained blood, and he knew that blood was poured into the right side of the heart by the great veins, but believed that only a little of it passed from the right ventricle into the lungs, the greater part of it passing through hypothetical pores in the septum and thus into the left ventricle. This opinion, like Galen's in other respects, remained unchanged until the middle of the 16th century. It was also known that valves existed within the veins, and that if an artery were tied on a living animal blood would cease to flow and pulsation be checked below the ligature, while if a vein were tied it shrunk above the ligature and became distended below.

Three men before Harvey's time came very near to discovering the secret that made him famous; in fact, they made such advances on what was already known that history should accord them a distinguished place. One was Columbus, who was born at Cremona in 1490, and died in 1559. He was first a pupil and prosector and then a friend of Vesalius, the great anatomist. Later he succeeded him at The University of Padua and unfortunately, after gaining his position, ungratefully turned upon his old teacher. He was, however, for his day a good anatomist and especially a good osteologist. It was he who first demonstrated experimentally that blood passes through the lungs into the pulmonary veins and that the latter connect with the left ventricle. He thus practically established the fact of the lesser circulation. He suffered, however, as did Servetus, from the prevailing notion that spirits and blood were mixed together. From Padua Columbus went to Pisa, and then to Rome. He wrote with elegance and correctness of style and even described the vessels which penetrate the bone cells, the ossicles of the ear, the minute anatomy of the teeth, the ventricles of the larynx, as well as those valves which prevent the return of blood from the lungs to the heart. In fact, he narrowly missed the significance of the actual facts of the case, simply failing in his final analysis and assembling of those facts which he had already demonstrated.

Cesalpinus, who lived a little later, came still nearer the mark, having accepted the teachings of Columbus regarding the course of the blood through the lungs. He added that the ultimate arterial branches connect with those of the veins, and he taught that blood and vital spirits, from which the ancients could never separate themselves, passed from the arteries into the veins during sleep, as was demonstrated by the swelling of the veins and the diminution of the pulse at that time.

A little later came Michael Servetus, who figures principally in history as a theologian and a victim of theologians, since he perished a martyr to Calvin's jealousy. He was, in effect, a wisely and widely educated man who did a great deal for science, one of the offences attributed to him being an edition of Ptolemy's geography, in which Judea was described as a barren and inhospitable land instead of one "flowing with milk and honey." This simple statement of a geographical fact was made a tremendous weapon of offence by Calvin, who replied that even if Servetus had only quoted from Ptolemy and, although there were ample geographical proofs, it nevertheless "unnecessarily inculpated Moses and grievously outraged The Holy Ghost." Servetus dared to deny the passage of the blood through the septum of the heart, and contended that that which comes into the right side was distributed to the lung and returned to the left ventricle. He published his views, however, in a religious treatise on Errors concerning The Trinity, a most unfortunate place in which to inject such an important fact, since it gave his enemies a still greater opportunity to vent and ventilate their spleen. Had he been able to leave out that notion of vital spirits, which prevailed with all his predecessors, he might actually have made the great discovery left for Harvey to enunciate. I have not been able to refer to original documents in this matter, but it is claimed by some that his description of the circulation was contained in another religious work concerning the Restitution of Christianity, which was printed in Nuremberg in 1790.

Such was the actual state of knowledge concerning the movements of the blood and the functions of the heart when Harvey published his great work. It behooves us now to proceed with a short account of Harvey's own life and researches.

William Harvey was born at Folkestone on the first of April, 1578. He was the eldest son of a prosperous merchant who raised a large family and who occupied the highest positions of honor in his own town. The son William was born to his second wife, by whom he had seven sons and two daughters. All of these children were helped to remunerative or honorable positions. They became merchants or politicians or secured prominence in some way, but William was the only one to study medicine. He was sent to the King's school at Canterbury, in 1588, and he was admitted at Caius, in Cambridge, in 1593, where he graduated in arts in 1597. The following year he went to Padua, which then had one of the greatest medical schools of the time, and he obtained his medical diploma in 1602, when twenty-four years of age. Returning to England he received a doctor's degree at Cambridge, and shortly afterward married a daughter of a London physician and entered upon the practice of medicine in London.

In the great city his practice as a physician seems to have been from the outset successful, and his knowledge and ability procured him various valuable appointments. He was made a Fellow of The College of Physicians in 1607. This Royal College of Physicians was given a grant of incorporation by Henry VIII in 1518, at the intercession of Chambers, Linacre and Ferdinand Victoria, the King's Physicians, it being under the patronage of Cardinal Wolsey. The first meetings were held at Linacre's house which he bequeathed to the corporation at his death. Until this College was founded practitioners of medicine were licensed to practise by the Bishop of London or by the Dean of St. Paul's.

A few years later Harvey was appointed Physician-Extraordinary to King James I, and later yet, after the publication of his great treatise and its dedication to the King, he was made Physician-in-Ordinary to Charles I, whom he attended during the Civil Wars.

It must have been about 1615 when Harvey first began expounding his views on the circulation of the blood, during lectures which were delivered at The College of Physicians, but it was not until thirteen years later, i. e., in 1628, that his great work DE MOTU CORDIS was published in Latin, as was customary among scholars, and at Frankfort-on-the-Main, since that was then the great center of the book publishing trade.

The treatise was dedicated to King Charles I, in a manner which to us would seem servile, and yet which was according to a custom followed by nearly all of the scholars of the day, who desired to attract not only the attention of royalty, but, in most instances, their benevolent assistance. It is worth while to quote at this point the first sentence or two of his dedication:

"To the Most Serene and Invincible CHARLES, of Great Britain, France and Ireland, KING: DEFENDER of the FAITH, Most Serene King,

"The heart of animals is the basis of their life, the principle of the whole, the Sun of their Microcosm, that upon which all movement depends, from which all strength proceeds. The King in like manner is the basis of his Kingdom, the Sun of his World, the heart of the Commonwealth, whence all power derives, all grace appears. What I have here written of the movements of the heart I am the more emboldened to present to your Majesty, according to the Custom of the present age, because nearly all things human are done after human examples and many things in the King are after the pattern of the heart."

The dedication was followed by a Proemium which one may hardly read to-day without emotion. In it he sets forth the mystery that has surrounded the subject of the motion and function of the heart, as well as the attendant difficulties of the subject, speaking of his own early despair that he would ever be able to clear up the subject. He even said that at one time he found the matter so beset with difficulties that he was inclined to agree with Fracastorius "that the movements of the heart and their purpose could be comprehended by God alone." Only later was this despair dispelled by a suggestion when, as he says: "I began to think whether there might not be a movement in a circle" when thus the truth dawned fully upon him.

We shall have to speak later of the opposition provoked by the appearance of this work and its almost general rejection. It is perhaps, however, but just to those who disputed Harvey's discoveries to recall that no complete and actual demonstration of the actual circulation was possible at that time, nor for many years after, and until the introduction of the microscope, the common magnifying glass of that day being the only lens in use. It remained for Malpighi to demonstrate the blood actually in circulation in the lung of a frog some three or four years after Harvey's death, in 1657. But Harvey lived long enough to see his views gain general acceptance, and though at first, and as the result of the opposition provoked by his publication, his practice fell off mightily, he later regained his professional position and rose to the highest eminence, being elected in 1654 to the Presidency of the College of Physicians. To this institution he proved a great benefactor, making considerable additions to the building after its destruction in The Great Fire of 1666 and its subsequent restoration. He also left a certain sum of money as a foundation for an annual oration, to be delivered in commemoration of those who had been great benefactors of the College. This oration is still regularly delivered on St. Luke's Day, i. e., the 18th of October, and is ordinarily known as the Harveian oration. In these orations more or less reference to Harvey's work and influence is always made.

This great man passed away on the 3d of June, 1657, within ten months of his eightieth birthday, thus affording a brilliant exception to the list of men who have rendered great service to the world and not lived long enough to see it appreciated.

As one reads Harvey's own words, the wonder ever grows that it should have remained for him, after the lapse of so many centuries, to not only call attention to what had been said by Galen but apparently forgotten by his successors, namely, that "the arteries contained blood and nothing but blood, and, consequently, neither spirits nor air, as may be readily gathered from experiments and reasonings," which he elsewhere furnishes. He furthermore shows how Galen demonstrated this by applying two ligatures upon an exposed artery at some distance from each other, and then opening the vessel itself in which nothing but blood could be found. He calls attention also to the result of ligation of one of the large vessels of an extremity, the inevitable result being just what we to-day know it must be, and the procedure terminating with gangrene of the limb.

Not long before Harvey's own publication, Fabricius, he of Aquapendente, had published a work on respiration, stating that, as the pulsation of the heart and arteries was insufficient for the ventilation and refrigeration of the blood, therefore were the lungs fashioned to surround the heart. Harvey showed how the arterial pulse and respiration could not serve the same ends, combating the view generally held, that if the arteries were filled with air, a larger quantity of air penetrating when the pulse is large and full, it must come to pass that if one plunge into a bath of water or of oil when the pulse is strong and full it should forthwith become either smaller or much slower, since the surrounding fluid would render it either difficult or impossible for air to penetrate. He also called attention to the inconsistencies between this view and the arrangement of the prenatal circulation; also to the fact that marine animals, living in the depths of the sea, could under no circumstances take in or emit air by the movements of their arteries and beneath the infinite mass of waters, inasmuch as "to say that they absorb the air that is present in the water and emit their fumes into this medium, were to utter something very like a figment;" furthermore "when the windpipe is divided, air enters and returns through the wound by two opposite movements, but when an artery is divided blood escapes in one continuous stream and no air passes."

Discussing further the views which he stigmatized as so incongruous and mutually subversive that every one of them is justly brought under suspicion, he reverts again to the statements of Galen, calling attention to the fact that from a single divided artery the whole of the blood of the body may be withdrawn in the course of half an hour or less, and to the inevitable consequences of such an act; also that when an artery is opened the blood is emptied with force and in jets, and that the impulse corresponds with that of the heart; again that in an aneurism the pulsation is the same as in other arteries, appealing for corroboration in this matter to the recent statements of Riolan, who later became his avowed enemy. Harvey also called attention to the fact that while ordinarily there was a seemingly fixed relation between respiration and pulse-rate, this might vary very much under certain circumstances, showing that respiration and circulation were two totally different processes. Harvey utilized also the results of his researches in comparative anatomy and physiology, for early in his work he called attention to the fact that every animal which is unfurnished with lungs lacks a right ventricle.

In his Proemium he then proceeds to ask certain very pertinent questions which can only be briefly summarized in this place. He asks: First, why, inasmuch as the structure of both ventricles is practically identical, it should be imagined that their uses are different, and why, if tricuspid valves are placed at the entrance into the right ventricle and prove obstacles to the return of blood into vena cava, and if similar valves are situated at the commencement of the pulmonary artery, preventing return of blood into the ventricle, then why, when similar valves are found in connection with the other side of the heart, should we deny that they are there for the same purpose of prevention "here the egress" and "there the regurgitation of the blood?"

Secondly, he asks why, in view of the similarity of these structures, it should be said that things are arranged in the left ventricle for the egress and regress of spirits, and in the right ventricle for those of blood?

Thirdly, he enquires why, when one notes the resemblance between the passages and vessels connected with the opposite sides of the heart, one should regard one side as destined to a private purpose, namely, that of nourishing the lungs, the other to a more public function? Furthermore, he enquires, since the lungs are so near, and in continual movement, and the vessels supplying them of such dimensions, what can be the use of the pulse of the right ventricle, which he had often observed in the course of his experiments? He sums up his inability to accept the explanations previously offered with a phrase which reads rather strangely, even in original Latin: "Deus bone! Quomodo tricuspides impediunt aëris egressum, non sanguinis." i. e., "Good God! how should the mitral valves prevent the regurgitation of air and not of blood?"

He then takes up the views of those who have believed that the blood oozed through the septum of the heart from the right to the left side by certain secret pores, and to them he replied "By Hercules, no such pores can be demonstrated, nor, in fact, do any such exist." Again, "Besides, if the blood could permeate the substance of the septum, or could be emptied from the ventricles, what use were there for the coronary artery and vein, branches of which proceed to the septum itself, to supply it with nourishment?"

Further on in the treatise Harvey sets forth his motives for writing, stating how greatly unsettled had become his mind in that he did not know what he himself should conclude nor what to believe from others. He says: "I was not surprised that Laurentius should have written that the movements of the heart were as perplexing as the flux and reflux of Euripus had appeared to Aristotle." He apologizes for the crime, as some of his friends considered it, that he should dare to depart from the precepts and opinions of all anatomists. He acknowledged that he took the step all the more willingly, seeing that Fabricius, who had accurately and learnedly delineated almost every one of the several parts of animals in a special work, had left the heart entirely untouched.

Passing more directly to the actual work of the heart, he shows that not only are the ventricles contracted by virtue of the muscular structure of their own walls, but further that those fibers or bands, styled "Nerves" by Aristotle, that are so conspicuous in the ventricles of larger animals when they contract simultaneously, by an admirable adjustment, help to draw together all the internal surfaces as if with cords, thus expelling the charge of contained blood with force. Later on he says that if the pulmonary artery be opened, blood will be seen spurting forth from it, just as when any other artery is punctured, and that the same result follows division of the vessel which in fishes leads from the heart. He furnishes a very happy simile to prove that the pulses of the arteries are due to the impulses of the left ventricle by showing how, when one blows into a glove all of its fingers will be found to have become distended at one and the same time. He quotes Aristotle, who made no distinction between veins and arteries, but said that the blood of all animals palpitates within their vessels and by the pulse is sent everywhere simultaneously, all of this depending upon the heart.

It is in Chapter Five of the treatise that he gives, probably for the first time, an accurate published account of just what transpires with one complete cycle of cardiac activity. The passage need not be quoted here, but deserves to be read by everyone interested in the subject, as who should not be? One sentence, however, is worth quotation or, at least, a summary, as follows: "But if the divine Galen will here allow, as in other places he does, that all the arteries of the body arise from the great artery, and that this takes its origin from the heart; that all the vessels naturally contain and carry blood; that the three semilunar valves situated at the orifice of the aorta prevent the return of the blood into the heart, and that they were here for some important purpose,--I do not see how he can deny that the great artery is the very vessel to carry the blood, when it has attained its highest triumph of perfection, from the heart for distribution to all parts of the body."

His Chapter Six deals with the course by which blood is carried from the right into the left ventricle, and here one must admire the large number of experimental demonstrations which Harvey had undertaken upon all classes of animals, for he speaks even of that which occurs in small insects, whose circulation he had studied so far as he could with the simple lens. Furthermore he described the prenatal circulation, omitting practically nothing of that which is taught to-day, showing that in embryos, while the lungs are yet in a state of inaction, both ventricles of the heart are employed, as if they were but one, for the transmission of blood. In concluding this chapter he again states briefly the course of the blood, and promises to show, first, that this may be so and, then, to prove that it really is so.