The growth of medicine from the earliest times to about 1800

by Albert H. Buck

The reader will, I believe, admit that this description, while perhaps not faultless, is distinctly superior to that given by Servetus.

Columbus’ experimental studies threw considerable light upon other matters relating to the physiology of the heart. He demonstrated, for example, that the fluid which enters the left ventricle from the lungs is genuine blood, and he also learned by the same method of investigation the true nature of the systole and diastole of the heart and the relations of these acts to the pulse and to the changes in the position of the heart. The discovery of all these facts constituted a material advance in our knowledge of the physiology of that organ; but, from this time onward, for a period of nearly three-quarters of a century, no further advance was made until William Harvey of England appeared on the scene. The explanation of the failure of such able investigators as Realdus Columbus, Vesalius, Servetus and others to push their researches still further is to be found largely in the fact that they were all still in bondage to the doctrines taught by Galen centuries earlier, and probably more particularly to that dogma which maintains that blood—if it is to be accepted as genuine or fully formed blood—must first have been elaborated in the depths of the liver. The impossibility of harmonizing such a dogma with the facts which by that time were well established, is too plainly evident to warrant further discussion in these pages.

Discovery of Valves in the Larger Veins by Fabricius ab Acquapendente.—The discovery of the presence of valves in the interior of the larger veins is credited by some to Cannani (1546) and by others to Fabricius ab Acquapendente (1574), but the best authorities appear to favor the claim of Fabricius to this honor. There are also a few authorities who maintain that Fra Sarpi, the celebrated monk and scientist of Venice, is entitled to be considered the discoverer of the valves in veins, but Tiraboschi, the historian of Italian literature, makes it clear that this claim is unfounded.

Although it was known to Fabricius that these valves are inclined toward the heart, he does not appear to have appreciated the fact that this arrangement is entirely incompatible with Galen’s doctrine that the flow of venous blood is from the liver toward the extremities; nor did any other anatomist, so far as I am able to learn, discover this incompatibility before it was pointed out by Harvey nearly fifty years later.

William Harvey, Who is Universally Acknowledged to be the Real Discoverer of the Circulation of the Blood.—William Harvey was born at Folkstone, England, in 1578, received his academic education at Caius College, Cambridge, and became a doctor of medicine in 1602, at the age of twenty-four. Four or five years before this event he went to Padua, Italy, to study medicine under Fabricius ab Acquapendente, who was considered at that period to be the ablest and most inspiring teacher of anatomy and physiology in Europe. It was from him, it may safely be assumed, that Harvey learned the importance of studying Nature herself, rather than books, when one is desirous of learning her secrets. Equipped with a thorough knowledge of the methods that may best be employed in making studies of this character, Harvey returned to England at the end of his long stay at Padua. He was soon afterward made a member of the College of Physicians of London, and in 1615 was elected to the Chair of Anatomy and Surgery in that institution. Later still, he was appointed one of the physicians of St. Bartholomew’s Hospital. He also held for several years the position of Court Physician, first to James the First and then to Charles the First. It was during this period of his professional career that he began working in earnest upon the problem of the circulation of the blood, and he kept steadily at this work throughout a period of several years. Among the manuscripts preserved in the British Museum there is one bearing the date of 1616 which shows that Harvey had already at this time reached conclusions which, in all essential respects, agree with those which appear in his final treatise published in 1628. The title of the latter work is, “Exercitatio anatomica de motu cordis et sanguinis in animalibus” (Frankfort, 1628).

Although, as I have shown above, several of the links in the chain of proofs bearing upon this question of the circulation had already been discovered before Harvey began his researches, he was not willing to accept them as proven facts until he had himself tested them thoroughly by the experimental method. Furthermore, they were often disconnected, and this lack of continuity obliged him to supply missing links at several points; in other words, nobody had as yet demonstrated the important fact that the blood travels regularly in an unbroken circuit, and it was to this great task that Harvey devoted himself at the period which we are now considering. He carried out all these investigations with the most painstaking care and made public announcement of his discoveries only after the lapse of an extraordinary length of time; his chief object being that ample opportunity might thereby be afforded for complete verification. The following are among the more important questions which he investigated and to which he furnished satisfactory solutions. He learned, for example, that the auricle and ventricle of each side of the heart do not contract simultaneously but in succession. When the right auricle contracts the blood which it then contains passes into the right ventricle; and when the right ventricle contracts the blood is driven into the pulmonary artery. From this vessel it passes ultimately into the pulmonary vein, and from the latter into the left auricle, which then contracts and drives the blood into the left ventricle. The latter chamber next contracts and forces the blood into the aorta, whence it is carried into all the arteries of the body. From these, in turn, it passes into the veins and thence back to the right auricle of the heart—the point from which it started. He corroborated the finding—by other anatomists who had preceded him—of membranous valves at the spots where the blood passes from one chamber to the other; and he compared these valves to little doors which open to permit the passage of the blood in one direction, but which close when there is any tendency for it to pass in the opposite direction. The valves of the right auricle, for example, allow the blood to pass into the right ventricle, but prevent it from returning into the auricle. Then, further, the valves of the right ventricle permit the blood to pass into the pulmonary artery, but prevent it from returning into the ventricle. The valves of the left auricle permit the blood to pass into the left ventricle, but do not permit it to return into the left auricle. Finally, the valves of the left ventricle allow the blood to pass into the aorta, but prevent it from regurgitating into the same ventricle. The valves with which the veins are equipped permit the blood to travel onward toward the heart, but do not permit it to back up into the arteries.

FIG. 15. WILLIAM HARVEY.

(After the portrait by Cornelius Jonson.)

Galen taught that the arteries pulsated by reason of a “pulsific power” which they derive in direct continuity from the tunics of the heart. He tried to prove the correctness of his doctrine by experimental methods, but in this he failed. Harvey was convinced that the arteries do not pulsate by reason of their own inherent power, but by a force of impulsion communicated to the blood at the heart. He refers to this question in the following terms: “When an artery is opened the blood escapes in jets of unequal force; the alternate jets being stronger than the intermediate, and the stronger jets corresponding in time of occurrence, not with the systoles but with the diastoles of the artery. The artery, therefore, must be distended by impulsion, by the shock of the blood. If the artery dilates by reason of its own inherent power, the blood would not be expelled with the maximum force at the very moment when this dilatation occurs.” As evidence of the non-existence of Galen’s assumed “pulsific power,” Harvey mentions the fact that, in the case of a patch-shaped calcification of the crural artery which came under his observation, the pulsation took place as usual, but at a point below (distal to) the edge of the patch. The intervening patch of rigid calcareous matter was not able to prevent the traveling onward of the propelling power.