William Harvey

William Harvey (1578-1657), English physician, who discovered the circulation of the blood and the role of the heart in propelling it. His work helped establish a new post-Galenic physiology (see Galen), and contributed to the scientific revolution in Europe. Employing the same methods of careful observation and clarity of thought, Harvey also formulated a new theory of generation and contributed to understanding the involvement of the nerves, brain, and muscles in sensation and movement.

Harvey was born on April 1, 1578, at Folkestone, Kent, and was educated at Gonville and Caius College, Cambridge. After graduating (BA) in 1597, he went to the University of Padua in Italy, Europe’s premier medical school. Here he learned from the celebrated anatomist Fabricius, a follower of Galen, although capable of criticizing ancient authority. Harvey also studied with the Aristotelian philosopher Cesare Cremonini. Unusually among 17th-century physicians, Harvey frequently used the physiology of Aristotle as his own starting point.

He returned to England with his medical degree in 1602, established a practice in London, and prospered. His election as a fellow of the Royal College of Physicians in 1607 was followed by an appointment to St Bartholomew's Hospital two years later. Harvey’s eminence received royal assent in 1618 when he became physician extraordinary to James I. He later attended Charles I, ultimately as senior physician in ordinary (1639). He continued to care for Charles during the English Civil War and remained a public supporter of the executed king during the period of the Commonwealth.

In 1615 the Royal College of Physicians appointed Harvey as Lumleian lecturer. His anatomical lecture notes provide early evidence of the ideas that would reach the public in his famous essay of 1628, Exercitatio Anatomica de Motu Cordis et Sanguinis in Animalibus (Anatomical Essay on the Motion of the Heart and Blood in Animals) (see Anatomy). After Aristotle, Harvey believed there was no separate soul distinct from living matter. There was only one substance with indivisible material and immaterial facets. Harvey considered the blood to be of central importance in animal life: it was this homogeneous fluid that was really alive. The body served as a vessel for the blood and gained its life as a result. By virtue of its crucial role in circulating the blood, the heart was the most important organ of the body. This theoretical underpinning to Harvey’s work harks back to ancient ideas.

However, in opposition to Galenic physiology, Harvey suggested that there were not two separate unidirectional systems (one based on the heart and arteries, the other on the liver and veins) but one united circulation of the blood passing through the heart in a continuous motion. He correctly elucidated the movements of the four chambers of the heart and the function these structures and their motion served. Without a microscope, he was obliged to speculate on the role played by the capillaries. The Italian anatomist Marcello Malpighi confirmed his conjectures in 1661. Harvey’s careful observation, dissection, and vivisection to determine the motion of the heart and circulation of the blood in a wide range of living animals (sometimes deer from the royal parks) set new standards for biological research, and in this way he has rightly been hailed as a founder of modern physiology.

Exercitatio Anatomica de Motu Cordis et Sanguinis in Animalibus brought severe criticism from some of his contemporaries, but Harvey was aware of his own worth and the quality of his research. His published response appeared in 1649 as Exercitations Duae de Circulatione Sanguinis (Two Essays on the Circulation of Blood).

The primacy of the blood also infused Harvey’s embryological research set forth in Exercitationes de Generatione Animalium (Essays on the Generation of Animals), substantially finished by 1638 but published in 1651 (see Development). His comparative investigation of oviparous (egg laying) and viviparous (live young) animals led to the first new theory of generation—epigenesis—since antiquity. His predecessors assumed viviparous generation, with a mixing of semen and menstrual blood to form a foetus, represented the basic means of generation, and oviparous animals the abstraction. Harvey turned this around, considering the formation of an egg before the embryo to be the basic model. A single drop of blood, endowed with powers of nutrition, sensation, and movement, simultaneously shaped, grew, and differentiated into an egg. The egg underwent further substantial change becoming a chick (oviparous) or foetus (viviparous). The semen had but a preparatory role and he rejected completely preformation (the notion that each living organism developed from an exact miniature of the adult within the seed or sperm). Unlike his work on the cardiovascular system, much of the value of Harvey’s embryological research lies in its stimulus to further investigation.

Harvey’s close association with the Royal College of Physicians included gifts of money for a library (sadly lost in the Great Fire of London of 1666), an endowment for a librarian, and an annual oration, the last two continuing today. He was elected president of the Royal College of Physicians in 1654, but he declined because of failing health, and died of a stroke in London on June 3, 1657.