EDITOR’S INTRODUCTION
However much the renewal of classical learning in the fourteenth, fifteenth, and sixteenth centuries may have furthered the development of letters and of art, it had anything but a favourable influence on the progress of science. The interest awakened in the literature of Greece and Rome was shown in admiration not only for the works of poets, historians, and orators, but also for those of physicians, anatomists, and astronomers. In consequence scientific investigation was almost wholly restricted to the study of the writings of authors like Aristotle, Hippocrates, Ptolemy, and Galen, and it became the highest ambition to explain and comment upon their teachings, almost an impiety to question them. Independent inquiry, the direct appeal to nature, were thus discouraged, and indeed looked upon with the utmost distrust if their results ran counter to what was found in the works of Aristotle or Galen. This spell of ancient authority was broken by the anatomists of the sixteenth century, who determined at all costs to examine the human body for themselves, and to be guided by what their own observations revealed to them; and it was finally overcome by the independent genius of two men working in very different scientific spheres, Galileo and Harvey. These illustrious observers were contemporaries during the greater part of their lives, and were some years together at the famous University of Padua. Galileo and Harvey refused to be bound by the teachings of Aristotle and Galen, and appealed from these authorities to the actual facts of nature which any man could observe for himself. Their scientific work is therefore of interest, not only for the innate value of the discoveries they made, but also because it shows them as pioneers in that independent spirit of scientific inquiry to which the great advance in natural knowledge since their time is so largely due.
Harvey’s work, by which his name has been made immortal, strikingly illustrates this. He was the first to show the nature of the movements of the heart, and how the blood moved in the body. He did so by putting on one side authority, and directly appealing to observation and experiment. The completeness of the success with which this independent line was taken, as exemplified in his treatise “On the Movement of the Heart and Blood,” is such as to excite the admiration of every modern physiologist. “C’est un chef-d’œuvre,” says a distinguished French physiologist, Flourens, “ce petit livre de cent pages est le plus beau livre de la physiologie.”[1]
The discovery made by Harvey was this: That the blood passed from the heart into the arteries, thence to the veins, by which it was brought back to the heart again; that the blood moved more or less in a circle, coming back eventually to the point from which it started. In a phrase, there was a Circulation of the Blood. Moreover, this circulation was of a double nature—one circle being from the right side of the heart to the left through the lungs, hence called the Pulmonary or Lesser Circulation; the other from the left side of the heart to the right, through the rest of the body, known as the Systemic or Greater Circulation. Further, that it was the peculiar office of the heart to maintain this circulation by its continuous rhythmic beating as long as life lasts.
This appears very plain and simple to us now—so easy that he who runs may read: as important as simple, for without this knowledge it is no exaggeration to say that a real understanding of any important function of the human body was impossible. And hence it has been contended with much force that not only the science of physiology, but the scientific practice of medicine date from this discovery. “To medical practice,” says Sir John Simon, “it stands much in the same relation as the discovery of the mariner’s compass to navigation; without it, the medical practitioner would be all adrift, and his efforts to benefit mankind would be made in ignorance and at random. . . . The discovery is incomparably the most important ever made in physiological science, bearing and destined to bear fruit for the benefit of all succeeding ages.”[2]
When Harvey first approached the subject, there were all kinds of crude and fantastic ideas regarding the functions and uses of the heart, bloodvessels, and blood—that the heart was the workshop in which were elaborated the spirits, a due supply of which was necessary for many parts of the body; that from the heart the arteries carried spirits, the veins nutriment to the different parts of the body; that the arteries contained blood and air mixed together, or only air; that fuliginous vapours, whatever they may be, passed from the heart along the bloodvessels; that the septum of the heart, by which its two sides are completely separated, was riddled with minute holes, like a fine sieve, through which the blood percolated from the right to the left side; again, that the heart was the organ in which the heat of the body was produced. Another favourite theory was that the blood moved from the heart along certain bloodvessels and back again by exactly the same channels, after the manner of the rise and fall of the tides, to which in fact the movement was likened. More curious still, even the best informed appeared to believe that the arteries terminated in nerves.
Notwithstanding these curious and erroneous speculations there was not wanting exact and wide knowledge of the anatomy of the human body. Indeed, before Harvey was born there had lived and died a most remarkable man known to fame as the “Father of Anatomy.” This was Vesalius. Vesalius’s knowledge of the human body was so profound that the only wonder is that he did not forestall Harvey in the discovery of the circulation. As the result of dissections of the body at the time when they could be carried out only with great difficulty, and often at the risk of severe penalties, Vesalius published, when only twenty-eight years of age, a treatise on Anatomy[3] which cannot fail to excite the astonishment and admiration of any modern acquainted with the subject. This work is illustrated with fine engravings made from drawings by John Calcar, a Flemish artist, and pupil of Titian.[4]
The distribution of the bloodvessels in the lungs and many other parts of the body, the general structure of the heart, the valves in the veins, were all known before Harvey arrived on the scene. More than this, the circulation through the lungs, or the Pulmonary Circulation, appears to have been known to one person at least. Michael Servetus, famous for his martyrdom on account of his religious opinions, in one of his theological works[5] does actually describe the blood as passing from the right side of the heart to the left through the lungs, and gives good reasons for his belief. Servetus, in his early days, had been with Vesalius prosector to John Guinterius of Andernach when Professor of Anatomy at Paris. Guinterius[6] speaks with admiration of the knowledge and abilities of his two young assistants. Like Vesalius, Servetus was therefore well acquainted with the anatomy of the body; but more, he was a physiologist; and no doubt when the cruelty of theological dispute sent him to the stake at the age of forty-four, it deprived physiology of a most promising investigator. The book in which the account of the Pulmonary Circulation is found has a most curious history. All copies of it, except one, were burnt with Servetus. This copy became the property of D. Colladon, one of his judges. After passing through the library of the Landgrave of Hesse-Cassel it came into the hands of a Dr. Mead, who undertook in 1723 to issue a quarto edition of it, but before completion the sheets were seized at the instance of Dr. Gibson, Bishop of London, and destroyed. The Duc de Valise is said to have given 400 guineas for the original copy, and at his sale it brought 3,810 livres. It is now in the National Library at Paris. It may well be questioned therefore whether the discovery of Servetus was ever known to the anatomists, including Harvey, who wrote after his death. One of these was Realdus Columbus, who published a work on Anatomy[7] six years after Servetus died, in which he shows that he clearly understood the valves of the heart, and describes the passage of the blood through the lungs. Columbus has been claimed as the real discoverer of the circulation and as having forestalled Harvey. But neither Servetus nor Columbus had any notion of the Greater or Systemic Circulation. And the latter actually says the heart is not muscular, and speaks of a to-and-fro movement of the blood in the veins.
But a third and much more serious precursor of Harvey as the discoverer has been brought forward in the person of Andreas Cæsalpinus[8] of Arezzo, justly renowned as the earliest of botanists. He actually used the word “circulation” in regard to the passage of the blood through the lungs. The claims of Cæsalpinus have been taken up with enthusiasm, not to say bitterness, in Italy; and in 1876 his statue was erected with much pomp and speechmaking in Rome, and an inscription placed upon it recording that he was the first discoverer of the circulation of the blood. It is much to be regretted that this display was not altogether free from a desire to depreciate Harvey. Wonder may well be expressed at this procedure, even after allowing for well-meant patriotic ardour, when it is learnt that in his works Cæsalpinus speaks of the arteries ending in nerves, of the septum of the heart being permeable, and its valves acting imperfectly, and of the veins carrying blood to the body for its nourishment. The statements made by Cæsalpinus, which at first sight point to his knowledge of the circulation, are altogether discounted on perusal of his works, and it becomes impossible to believe that he had any clear idea of the circulation as we understand it to-day. The misconception has no doubt arisen from the interpretation of isolated passages in the light of what we now know regarding the circulation. Moreover, it is impossible to believe, seeing how well the works of Cæsalpinus were known, that, had he ever been regarded as putting forward in them the doctrine of the circulation as we now understand it, such a new and startling view would not have attracted the attention of the distinguished anatomists who were his contemporaries or immediate successors. But that none of them ever for a moment saw any such doctrine in the works of Cæsalpinus is shown by their writings, and by the surprise with which Harvey’s discovery was received.
Even Shakespeare has been cited as being acquainted with the circulation of the blood, because he refers to its movement. This only illustrates the confusion which has often been made of movement with circulation. From the earliest times it had been believed there was movement of the blood, but there was no clear or correct idea as to the nature of the movement. The view may be ventured that another confusion is responsible for a good deal that has been said about Harvey having been forestalled in the discovery. It is confusing the passage through the lungs of some blood with the whole mass of it. It is difficult to believe, on taking a broad view of all their statements on the subject, that any of Harvey’s predecessors realised that the whole mass of the blood was continually passing through the lungs. Had they done so it is further difficult to see how the systemic circulation should have escaped them. But of this they certainly had no idea.
We may admit all this previous knowledge without its detracting from the greatness and merit of Harvey’s work. Although the same anatomical facts, and even a glimmering of the Pulmonary Circulation may have been present to the minds of his predecessors or contemporaries, yet the genius, the spark of originality by which was discovered the proper relation to one another of the former, the true significance and meaning of the latter, belongs to Harvey and to him alone.
As was said by one of the best informed minds[9] of the eighteenth century: “It is not to Cæsalpinus, because of some words of doubtful meaning, but to Harvey, the able writer, the laborious contriver of so many experiments, the staid propounder of all the arguments available in his day, that the immortal glory of having discovered the Circulation of the Blood is to be assigned.”
William Harvey was born on April 1, in the year 1578, at Folkestone, the eldest of seven sons of a well-to-do Kentish yeoman. When ten years old he was sent to the Grammar School at Canterbury, and remained there until he was fifteen. He then proceeded to Caius College, Cambridge, where after three years’ residence he took the usual degree. Desiring to enter the medical profession, he adopted a course, not unusual at that time, of going abroad to study at a Continental University, a course due to the absence of scientific teaching in the English Universities on the one hand, and to its excellence in those of the Continent on the other. Consequently, in the year 1597, when nineteen years of age, Harvey directed his steps towards Padua, then famous throughout Europe for its medical school, and especially for its school of anatomy. Earlier in the century the chair of Anatomy had been filled by Vesalius; it was now occupied by another celebrated anatomist, known as Fabricius of Aquapendente. Harvey enjoyed the advantage of studying anatomy under this great teacher, and the visitor to Padua to-day can see the little anatomical theatre with its carved desks, over one of which, no doubt, our illustrious discoverer leant with eager attention whilst Fabricius demonstrated on the body below. We can see the professor with pride explaining to his pupils the valves in the veins which he had discovered, yet not appreciating their meaning and importance; that was to be done a few years hence by the young student listening above. It is very interesting to learn that at this time Galileo was also a professor at Padua, and was lecturing with such success that students flocked to hear him from all parts of Europe. Surely it is difficult to imagine any seat of learning more distinguished and attractive than the University of Padua must have been during the five years Harvey spent there. At the end of this time he received his degree of doctor, the diploma for which is couched in the most eulogistic language, showing how by his studies and abilities he had attracted the attention and earned the commendation of the distinguished professors who then held the chairs of Anatomy, Medicine, and Surgery in the University. He now returned to England, and was granted the degree of Doctor of Medicine by the University of Cambridge.
Soon after, Harvey settled in London and began to practise. In 1607 he was elected a Fellow of the Royal College of Physicians, and in 1615 was appointed Lecturer in Anatomy to that ancient and important foundation. In 1609 he had been elected physician to St. Bartholomew’s Hospital.
In 1616, the year Shakespeare died, Harvey probably began in his classes to teach that doctrine which has immortalised his name. He began to show his pupils, and whoever else desired to be present, from dissections of the human body and of animals, and by experiment when necessary, the true office of the heart, the true course of the movement of the blood in the body. This he continued to do for more than ten years, listening patiently to objections, indeed inviting criticisms so that the complete truth might be discovered free from any falsities or misconceptions. At last, upon the earnest entreaties of his most distinguished medical friends, he was persuaded to publish his discovery to the world. These facts are of interest in throwing some light on Harvey’s character. A discoverer who waits years before publishing what he is firmly convinced in his own mind is a new idea, not to say a great discovery, must be possessed of that calmness of mind and abnegation of self which we associate with the true philosopher. A discoverer who employs so long an interval to give opportunity for criticism, and to deal with objections, must indeed be wedded to truth.
This devotion to truth, however, had its reward, for it resulted in one of the most remarkable scientific treatises ever written. When, in 1628, Harvey published at Frankfort-on-Main, his book on “The Movement of the Heart and Blood,” he gave his reasons for believing the blood to circulate, and explained the use of the heart in language so simple, so clear, so exact, that now, nearly three hundred years afterwards, the most accomplished physiologist can hardly improve on it. This assuredly is a fact almost unique in the history of science.
And yet with all this the fact remains that Harvey never really knew, from the nature of the case could not know, how the blood passed from the arteries to the veins—how, in other words, an essential part of the circulation was actually accomplished. The blood passes from the arteries to the veins through minute microscopic tubes termed capillaries. In Harvey’s day the microscope was not sufficiently powerful to reveal such fine structures to human vision, and he was therefore necessarily ignorant of their existence. Looked at from this point of view, the discovery affords a very good example of what has been aptly termed the scientific use of the imagination. Although, with his imperfect microscope, it was impossible for him to know how the blood actually passed from the arteries to the veins, yet as the result of his observations and experiments he was able to infer and to state the grounds for his inference in clear, forcible, and most convincing language, that the blood must circulate, and circulate in one direction only, viz. from the heart into the arteries, thence to the veins, by which it was brought back to the heart again. His imagination was thus enabled to bridge over the gulf between the arteries and veins which his eyes, with the imperfect instrument then alone at his disposal, were quite unable to cross. It was not until four years after Harvey’s death that the microscope had been sufficiently improved to enable an Italian anatomist named Malpighi,[10] in the year 1661, to actually observe the capillaries uniting by their networks arteries and veins.
The work was published at Frankfort doubtless that it might be more easily disseminated over the Continent. It made a sensation among the learned of all countries. Its conclusions were opposed by the older physicians; but by the younger scientific men it was by no means received with disfavour. Amongst the latter was the philosopher Descartes, whose name was then a power in Europe. The philosophical, yet keenly practical mind of Descartes grasped the discovery with avidity and supported it with ardour. In his celebrated “Discours de la Méthode,”[11] he refers to the discovery of “an English physician,” and describes with enthusiasm the anatomy and use of the heart. Although we have no certain information on the point it is quite possible that Descartes may have known Harvey, for in the year 1631 he is said to have paid a visit to England; and in his second reply to Riolan Harvey refers to “the ingenious and acute Descartes,” and says the honourable mention of his name demands his acknowledgments. Thus the discovery became widely known and largely adopted.
One result of the publication of his discovery was only in keeping with the experience of many great and original minds before and after his time. In the things of this world his discovery was of little service to him. His practice fell off. Patients feared to put themselves under the care of one who was accused by his envious detractors of being crack-brained, and of putting forward new-fangled and dangerous doctrines. One who knew Harvey writes as follows: “I have heard him say that after his booke of the Circulation of the Blood came out he fell mightily in his practice, and ’twas believed by the vulgar that he was crack-brained, and all the physitians were against him, with much adoe at last in about 20 or 30 years time it was received in all the universities in the world, and as Mr. Hobbs says in his book ‘De Corpore,’ he is the only man perhaps that ever lived to see his own doctrine established in his lifetime.”[12]
There was one striking exception to this treatment. The King, Charles I., not only appointed Harvey his physician, but showed the liveliest interest in his discovery. Harvey explained his new doctrine on the body before the King. Whatever opinions may be held regarding the moral and political character of that unfortunate monarch, it must be admitted that in aiding and befriending Vandyke and Harvey he showed himself an enlightened patron of both art and science. Harvey continued the King’s physician, and held this position when, in 1641, Charles declared war against the Parliament. It is here curious to learn that although openly declared enemies the Parliament was still mindful of the King’s person, for not only with their consent, but by their desire, Harvey remained his physician.[13] Notwithstanding his intimate connection with the Court, Harvey appears to have taken no active part in the great political struggle now taking place. The little solicitude he had for it is shown by an anecdote told of him at the first battle of the Civil War. “When King Charles,” says a contemporary author,[14] “by reason of the tumults left London, Harvey attended him, and was at the fight of Edgehill with him: and during the fight the Prince and the Duke of York were committed to his care. He told me that he withdrew with them under a hedge, and tooke out of his pocket a booke and read. But he had not read very long before a bullet of a great gun grazed on the ground near him, which made him remove his station.” This anecdote well illustrates Harvey’s calm and peaceful character. This was also shown by the restrained and dignified manner in which he treated the many writers who attacked him, sometimes in anything but choice language, after the publication of his great discovery. Anything like controversy for controversy’s sake was wholly foreign to his nature. “To return evil speaking with evil speaking,” he remarks in a reply to one of his critics, “I hold to be unworthy of a philosopher and a searcher after truth. I believe I shall do better and more advisedly if I meet so many indications of ill breeding with the light of faithful and conclusive observation.”[15] To many of the attacks made on his discovery or on himself, he therefore did not condescend to reply. And when from the eminence of his opponents he felt called upon to do so, he replied with the utmost courtesy and kindliness. But whilst admitting the high claims to distinction on other grounds of his antagonist, he proceeded on this particular question to utterly demolish him with clear facts and stern irrefutable arguments and experiments. He called upon his opponents to observe the facts and make the experiments for themselves, instead of citing the opinions of authors centuries old, or making long discourses on spirits, fuliginous vapours, and the tides of Euripus. This is well illustrated in his replies to Riolan. The arguments of Riolan would hardly seem to have entitled him to the honour of the special notice of the great discoverer. But probably his position as Anatomist in the University of Paris, and of physician to the Queen-Mother, Marie de Medicis, made Harvey pick out his criticisms as a suitable excuse for replying to his opponents. Harvey’s mode of argument is well shown by the following admirable remarks on the Manner and Order of Acquiring Knowledge, in his introduction to the work on “The Generation of Animals”: “Sensible things are of themselves and antecedent; things of intellect however are consequential and arise from the former, and indeed we can in no way attain to them without the help of the others. And hence it is that without the due admonition of the senses, without frequent observation and reiterated experiment, our mind goes astray after phantoms and appearances. Diligent observation is therefore requisite in every science, and the senses are to be frequently appealed to. We are, I say, to strive after personal experience, not to rely on the experience of others: without which indeed no one can properly become a student of any branch of natural science.” Referring to his own particular work he says: “I would not have you therefore, gentle reader, to take anything on trust from me concerning the Generation of Animals: I appeal to your own eyes as my witness and judge. For as all true science rests upon those principles which have their origin in the operation of the senses, particular care is to be taken that by repeated dissection the grounds of our present subject be fully established. . . . The method of investigating truth commonly pursued at this time therefore is to be held erroneous and almost foolish, in which so many inquire what others have said, and omit to ask whether the things themselves be actually so or not.”
When the King made Oxford his headquarters, Harvey was with him, and was appointed head of Merton College. But in 1646, on Oxford surrendering to the Parliamentary forces, he gave up his wardenship and quitted the city. Having no call to take an active part in the political contest, and now verging on threescore-and-ten, he retired from his position of physician to the King and went to London, where he was hospitably entertained in the houses of his brothers, who were wealthy merchants in the City. Here he no doubt once again devoted himself to scientific observation, the nature of which became evident, when in 1651 he was persuaded, somewhat against his own inclination, by his friend, Dr. George Ent, to allow the publication of his book on “The Generation of Animals.” In this work he appears as a pioneer in the difficult science of Embryology, working under most adverse conditions, for he had no microscope worthy of the name. Whilst, therefore, of no great value in the light of our present knowledge, it is a monument of the author’s industry and of his enthusiastic devotion to physiological research. It contains a great number of acute and interesting observations; and he had evidently made many more, for he says that his papers on the Generation of Insects were lost as a result of the tumults which arose at the outbreak of the Civil War. He told Aubrey that no grief was so crucifying to him as the loss of these papers. The King took a direct personal interest in these investigations,[16] and supplied him with deer from the Royal Parks in order to further them.
In two respects the work on Generation is worthy of more than a mere passing notice, and entitles its author to the possession of almost prophetic genius. The first is the enunciation of the great generalisation omne vivum ex ovo. Although this particular phrase is nowhere to be found, as is often erroneously stated, in the treatise on Generation, yet a perusal of Exercises I., LI., and LXII. will convince any one that Harvey had grasped this great idea, which has since been so abundantly verified. The other is his doctrine of Epigenesis, or the formation of the new organism from the homogeneous substance of the germ by the successive differentiation of parts, that all parts are not formed at once and together, but in succession one after the other. He put forward this doctrine of Epigenesis in contradistinction to that of Metamorphosis, according to which the germ was suddenly transformed into a miniature of the whole organism which subsequently grew. This is certainly very remarkable, and entitles him to be regarded as a forerunner of Caspar Wolff, Von Baer, and the modern Evolutionary School, which sees in the development of the organism from the ovum a passage from the homogeneous to the heterogeneous by a gradual process of differentiation, from a germ in which there is no sign of any of the parts of the adult to an organism with all its many and varied organs. Commenting on certain passages of Exercise XLV., in which Harvey specially refers to this subject, the late Professor Huxley remarked: “In these words, by the divination of genius, Harvey in the seventeenth century summarised the outcome of the work of all those who, with appliances he could not dream of, are continuing his labours in the nineteenth century.”[17]
In addition to his long sojourn in Italy as a student, Harvey made several other visits to the Continent. In 1630 he consented to accompany the young Duke of Lennox in his travels abroad. He had returned by 1632, for in that year he was formally appointed physician to Charles I. Again, in 1636 he accompanied the Earl of Arundel on his embassy to the Emperor, and was absent some nine months. According to Aubrey, in 1649 Harvey, with his friend Dr. George Ent, again visited Italy. Some doubt has been thrown on this journey, but it receives support from a letter of Harvey’s to John Nardi, of Florence, written on November 30, 1653, in which he concludes by asking his correspondent to mention his name to his Serene Highness the Duke of Tuscany, “with thankfulness for the distinguished honour he did me when I was formerly in Florence.”
In his old age Harvey was honoured in a striking manner by those best fitted to judge of the merit and value of his life’s work. His statue was erected in the hall of the College of Physicians. As an acknowledgment, as it were, of this remarkable compliment, he built at his own expense a Convocation Hall and a Library as additions to the College, and contributed books, curiosities, and surgical instruments for the Library and Museum. Not content with this, he made over to the College, the year before he died, his paternal estate, stipulating that a certain sum out of it should be employed every year for the delivery of an Oration in commemoration of benefactors of the College, and of those who had added anything to medical knowledge during the year. This Oration is annually delivered by some distinguished member of the medical profession, and is inseparably associated with the name of Harvey. This graceful act shows how in his declining years Harvey’s thoughts were turned to the future. It had for its object to further the progress of scientific knowledge, to stimulate studies in the pursuit of which he had shown himself such a master. He wished when old and infirm, bereft of the power of again entering the arena of active work and investigation, to still do something to increase and extend that knowledge which is of so great service to mankind—a knowledge of the human body in health and in disease.
Harvey died on June 3, in the year 1657, in the eightieth year of his age, and was buried at the village of Hempstead, in Essex, in a vault which had been built by his brother Eliab.
E. A. Parkyn.
London, November, 1906.
The following is a list of Harvey’s works, and of the more important references to his life and discovery:—
“MS. Memorandum Book,” dated 1616, entitled “Prælectiones Anatomicæ Universalis.” It is in Harvey’s handwriting, and contains the origin of the Circulation. (In the British Museum.) A Facsimile was published in 1886 by the College of Physicians.
“MS. De Musculis,” 1627, in Harvey’s handwriting. (Brit. Mus.) A Notice on this manuscript was published in 1850 by G. E. Paget, M.D.
“MS. of Prescriptions,” 1647. (Brit. Mus.)
“MS. Diploma of Doctor of Medicine” to Harvey by University of Padua, April 25, 1602. (In the College of Physicians.)
“MS. Illuminated Grant of M.D.,” by University of Padua to an Englishman, Thomas Heron, which is witnessed by “Guigliomo Harveo Consiliaris Magnificæ Nationis Anglæ.” It is dated March 19, 1602. (Brit. Mus.)
“MS. Oratio Harveiana,” 1661, ab. E. Greaves. (Brit. Mus.)
“De Motu Cordis et Sanguinis,” Frankfort-on-Main, 1628. First English edition published by R. Lowndes, with preface by Zachariah Wood, Physician of Rotterdam, 1653.
“Anatomical Examination of the Body of Thomas Parr, aged 152 years,” made in 1635, but not published until 1669 in Betts’ “De Ortu et Natura Sanguinis.”
“Two Disquisitions in Reply to John Riolan, jun.,” 1649.
“De Generatione Animalium,” London, 1651; in English, 1653.
“Biographica Britannica,” 1750. The Life of Harvey, containing much curious information and discussion, is evidently that on which all subsequent biographies are based.
“Harveii Opera Omnia,” edited by Dr. Akenside, with Life by Thomas Lawrence, M.D., 1766.
“Lives and Letters of Eminent Persons,” by John Aubrey, 1813.
“Records of William Harvey, with Notes,” by James Paget, of St. Bartholomew’s Hospital, 1846.
“The Works of William Harvey,” translated by Robert Willis, M.D. (Sydenham Society, 1848). This excellent translation has been followed in the present volume.
“Histoire de la Découverte de la Circulation du Sang,” par M. J. P. Flourens, 1854.
“Circulation of the Blood: its History, Cause, and Course,” by G. H. Lewes in “Physiology of Common Life,” 1859.
“Memorials of Harvey,” collected by J. H. Aveling, 1875.
“William Harvey: a history, etc.,” by Robert Willis, M.D., 1878.
“Roll of the Royal College of Physicians,” by William Munk, M.D., 2nd ed., 1878.
Huxley on “Evolution,” in “Encyclopædia Britannica,” 9th ed., 1878.
“Experimental Physiology,” by Sir R. Owen, 1882.
“A Defence of Harvey,” by George Johnson, M.D., 1884.
“Masters of Medicine: William Harvey,” by D’Arcy Power 1897.