Renaissance Anatomy

The study of human anatomy flourished in the sixteenth and seventeenth centuries. The two men most closely associated with the advancement of anatomy in this period are Andreas Vesalius (1514 – 1564) and William Harvey (1578-1651). In 1543, Vesalius published what is widely regarded as the first modern work of anatomy, De humani coporis fabrica (hereinafter referred to as the Fabrica). In this book, Vesalius took it upon himself to challenge and correct the work of the ancient physician Galen, long considered the highest authority on the subject of human anatomy. Throughout the Fabrica, Vesalius points out each and every instance where what he has seen during dissections does not match what he has read in Galen, and he insists on giving greater weight to the evidence of his own eyes than to the authoritative ancient text. The Fabrica is also notable for the large number and high quality of its illustrations, which greatly enhance the verbal argument. Vesalius worked closely with artists from the studio of Titian to produce woodcuts with an unprecedented level of detail and aesthetic appeal. Vesalius’ challenge to the authority of Galen came to full fruition in the work of William Harvey. In his 1628 book De motu cordis, Harvey announced his discovery that blood circulates, thus mounting a radical challenge to traditional understandings of physiology. Both Vesalius and Harvey have been lauded for their willingness to look at bodies with their own eyes and to privilege the evidence of the senses instead of the texts of the ancients. Harvey’s statement that he aimed “to learn and teach anatomy not from books but from dissections” (p. 6) has been oft quoted and taken as representative of a distinctively modern and scientific approach to the study of anatomy. But more recent scholarship has revealed a far more complex and interesting story.

Anatomists enjoyed the patronage of emperors, kings, princes and popes. The young (he was only twenty-eight when the Fabrica was published) and ambitious Vesalius was not satisfied with his position as professor at the University of Padua and he actively sought a position at the court of the Holy Roman Emperor Charles V. He dedicated the Fabrica to Charles V and sent the emperor a sumptuous presentation copy, printed on vellum, hand colored and bound in purple velvet. In the dedicatory preface, Vesalius praised Charles for his “amazing love for all disciplines.” Noting Charles’ interest in mathematics and cosmology, Vesalius commented: “Because you are so uniquely fascinated by the study of the world, I am quite sure that you will be delighted also to study the construction of the most perfect of all creatures and will take pleasure in examining the lodging-house and instrument of the immortal soul. . . . ” In his bid for imperial patronage, Vesalius presented anatomy not simply as a subject of interest to physicians, but one that was properly the domain of all educated Christian men.

Katherine Park argues that Vesalius’ decision to place a female cadaver in the center of his title page and to have himself depicted dissecting the uterus was also part of his efforts to secure a position at the imperial court (Park, pp. 234-240). The Hapsburg family had constructed a dynastic mythology that linked their rule to that of the Julio-Claudian emperors of ancient Rome. The first in this line was Julius Caesar, who as a baby was cut out of his dead mother’s womb. The last was Nero who, according to a widely circulated (albeit apocryphal) story, had his own mother Agrippina killed and cut open so he could see her womb, the place where he originated. Park notes that textual accounts as well as images of Caesar’s birth and Agrippina’s dissection circulated widely from the late middle ages into the sixteenth century. Park contends that contemporary readers, particularly those affiliated with the Hapsburg court, would have understood Vesalius’ title page as an allusion to both Caesar and Nero. Vesalius thus connected his resurrection of the Roman anatomy of Galen with the resurrection of the Julio-Claudian line in Hapsburg imperial rule. Vesalius’ maneuvering was successful, and in 1543 he became the personal physician of Charles V. His position as imperial physician gave him even greater access to bodies than he had had as a university professor. As a result, he was able to conduct many more dissections and autopsies and produced an expanded and revised edition of the Fabrica in 1555.

William Harvey dedicated De motu cordis to Charles I: “The animal’s heart is the basis of its life, its chief member, the sun of its microcosm; on the heart all its activity depends, from the heart all its liveliness and strength arise. Equally is the king the basis of his kingdoms, the sun of his microcosm, the heart of the state; from him all power arises and all grace stems.” In 1630 Charles made Harvey his personal physician. This position certainly enhanced Harvey’s prestige and that of his radical new account of the motion of the heart and blood. But it also afforded Harvey new opportunities to pursue further anatomical studies. Harvey’s later book on generation was based in part on extensive dissections of deer. “I shall,” he announced, “investigate the generation of all viviparous animals from the account of the hind and doe as being the most convenient exemplar.”  This animal was a “convenient exemplar” because Charles allowed Harvey to dissect deer that he and his courtiers shot in the Royal Deer Park. They hunted the females during the breeding season, which gave Harvey the opportunity to dissect does shortly after copulation and to observe the very earliest stages of pregnancy and fetal development. Harvey wrote proudly that the king took a personal interest in these investigations, “and was pleased many times to be an eye-witness to my discoveries.” (336) Royal patronage had its drawbacks though. When the English civil war broke out in 1642, Harvey, as a known Royalist, was targeted. Parliamentary troops plundered his London lodgings and he lost numerous books, papers and, most unfortunately for posterity, the draft of a book on pathological anatomy. His patron was beheaded in 1649, although this did not stop Harvey from including references to him in De generatione, which was published in 1651.

In order to understand Harvey’s achievement in De motu cordis, it will be useful to briefly review the pre-existing, Galenic, understanding of the heart and blood. Galen had asserted that there were two types of blood: venous and arterial. Venous blood was a kind of refined nourishment produced in the liver. When food was consumed it was first digested in the stomach, then underwent further processing ion the intestines, and finally moved to the liver where it was transformed into venous blood. Venous blood flowed outward from liver to vena cava to all parts of body through veins. Galen believed that each part of body drew nourishment to itself as it needed. In other words, it was the centrifugal activity of he various parts of the body that impelled blood flow in the veins, not a central impulse pushing it. Venous blood did not move regularly; it was attracted by the different parts of the body as and when they needed nourishment and could move in both directions in the veins. Arterial blood, by contrast, was made in the heart. A certain amount of venous blood traveled from the liver to right side of heart. Some of this blood nourished the heart, but a portion of it moved from the right side of the heart to the left side through pores in the interventricular septem (the fleshy wall separating ventricles of heart). Meanwhile air from the lungs also traveled into the left side of the heart through the pulmonary vein. The mixture of venous blood and air in the left ventricle of the heart formed arterial blood. Arterial blood moved out from the heart to the rest of the body through the arteries. However, it was not “pumped” out by the heart. The arteries had their own “pulsative faculty” that caused them to propel blood around the body. Whereas venous blood was merely nourishment for the body, arterial blood was a more refined substance that conveyed life and vitality. Hence the observation that it was far more dangerous to cut an artery than to cut a vein. The mixing of venous blood and air produced some waste vapors, and these moved back through the pulmonary vein into lungs where they were breathed out. Galen believed that diastole – dilation – was the active phase of heartbeat. During diastole the heart sucked blood into right ventricle and air into left. During systole – contraction – the heart was at rest. Both venous blood and arterial blood were used up by the parts of the body and new blood was created – blood was not re-circulated

Anatomists in the sixteenth century called into question various aspects of Galenic physiology and Harvey built on their work. Vesalius argued that the vena cava did not originate in liver, although he continued to accept the idea that the liver produced blood. Further, he denied that the interventricular septem is permeable because he could not see any pores in the hearts of any of the cadavers he dissected. (He was not the first to raise this criticism. Niccolo Massa also questioned the permeability of the septem.) Two later anatomists, Realdo Columbo (d. 1559) and Hieronymus Fabricius ab Aquapendente (1533 – 1619), who both taught at Padua after Vesalius, had significant influence on Harvey. Columbo discovered the pulmonary transit of blood, that is, that blood moves from the heart to the lungs and back to the heart. He was also the first to realize that the active phase of the heartbeat is systole, not diastole. Columbo made extensive use of animal vivisections in his work, which was a methodology that Harvey followed closely. Fabricius published a study of the valves in the veins in 1603. Although he was not the first to discover the valves (Alessandro Achillini had described them earlier), he was the first to discuss them at length and to show how they constrained blood flow in the veins.

Harvey’s second major work (his “other book”) was Dissertations on the Generation of Animals, to which append others on Parturition, on Membranes and Humors of the Uterus, and on Conception. With seventy-two chapters, it was five times as long as De motu cordis, and arguably achieved more rapid success. It was printed four times in 1651, once in London (quarto), and three times in Amsterdam (duodecimo), and it was translated into English in 1653. Like De motu cordis, De generatione was based on extensive dissections of animals and humans. Harvey even claims that he was able to dissect human embryos at various stages of development. Based on this work Harvey claimed that: During intercourse (or not!), the male “impressed a prolific power on the female, it either escapes out of the body, or is dissolved, or is turned into vapor and vanishes . . . . ” Male renders female fertile, result is conception of offspring. However, male makes no material contribution. This “conception” was an egg, hence Harvey’s assertion that all animals come from eggs. The mammalian conception in the uterus was an internal egg; in birds and reptiles the conception was an external egg. But Harvey also differed from Aristotle because he argued that the mother made no material contribution to reproduction either. Rather, he asserted that, “The ‘conception’ . . . of the uterus or the ovum resembles, at least in some sort, the conception of the brain itself, and in a similar way does the ‘end’ inhere in both. For the ‘species’ or ‘form’ of the chick is in the uterus or ovum without the intervention of matter . . . ” In other words, the uterus conceives an ovum as the brain conceives an idea. Neither is a material process. As evidence for this: 1) Fertilization at a distance possible – chickens can lay unfertilized eggs; 2) penetration of semen into uterus impossible – experiments with hens, tried to inflate uterus with air from vagina, but could not; 3) Nothing visible in the cavity of the uterus after intercourse – experiments on deer from Royal Deer Park – not till sometime after intercourse that “conception” occurs – production of egg (ovum); and 4) gross inner structure of the uterus “when ready to conceive, is very like the structure of the brain.” Harvey, like Galen and like his medieval and Renaissance predecessors, saw in the anatomy and physiology of reproduction the presence of the divine: “A superior and more divine agent than man, therefore, appears to engender and preserve mankind, a higher power than the male bird to produce a young one from the egg. We acknowledge God, the supreme and omnipotent Creator, to be present in the production of animals, and to point, as it were, with a finger to his existence in his works, the parents being in every case but as instruments in his hands.”

Sources:

William Harvey, The Circulation of the Blood and other Writings, trans. Kenneth J. Franklin (London: J.M. Dent, 1993).

Park, Secrets of Women

Vesalius