William Harvey Biography

William Harvey, the discoverer of blood circulation, was born in Folkestone, England on April 1, 1578. He went up to Cambridge in 1593, where he received his B.A. in 1597, after which he journeyed to Padua in Italy to study medicine. Padua was reputed to be one of the finest universities at the time and had many famous scholars, including Galileo, while Harvey was a student. Harvey received his medical degree in 1602. Back in England, he became a Fellow of the Royal College of Physicians in 1607, and was appointed to the Saint Bartholomew Hospital, London where he served from 1609 until 1643. He attended the death of James I and he was the personal physician to Charles I. He became President of the Royal Society of Physicians in 1654. Obviously, Harvey was an extraordinarily distinguished physician. However, his publication on the circulation of blood in 1628, a notable example of experimental biology, and correct in its interpretations and conclusions, earned for him scorn and he was denounced by the major scholars of the day. It resulted in significant injury to his practice.

It is difficult in the modern world to understand the tenacious hold ancient scholars had on the world in the time of Harvey. Galen's (born in 129 in Pergamon which is now called Bergama and is located in Turkey) view of the function of the heart and vessels remained paramount and unchanged for 1,400 years. Galen held that the liver was the most important organ in the blood-vascular system. Galen believed that the liver was the site of blood formation and venous blood from the liver moved throughout the body. This blood ebbed and flowed as the tides, i.e., back and forth. He thought that some venous blood from the liver moved to the right auricle and to the right ventricle. Here it gave off noxious vapors which dissipated via the lungs. The remainder of the right ventricular blood moved from there to the left ventricle via tiny pores. Blood in the left ventricle was mixed with blood of the arteries and air from the lungs and it then went to the periphery of the body where, like venous blood, it ebbed and flowed in the system. Note, these beliefs of Galen were not harmonious with the notion that blood circulated.

Harvey, after carefully examination of animal and human hearts, wrote his famous Exercitatio anatomica de Motu Cordis et Sanguinis in Animalibus which challenged and corrected the assertions of his ancient predecessor. Harvey looked for pores in the septum between the ventricles. He looked, "but, damn it, no such pores exist, nor can they be demonstrated" (an English translation of Harvey who wrote in Latin). He monitored the beating heart, made rough calculations of the volume of blood leaving the heart per unit time and compared that with the total blood volume. He concluded that blood could not be produced fast enough to account for this volume, thus it must circulate. He examined valves in veins. He concluded that venous blood could move in only one direction and that was toward the heart. His conclusions were made from direct observation, often of living animals, and the observations led him to postulate that blood was in motion all of the time and that it circulated. As far as contemporary knowledge of circulation is concerned, the only information missed by Harvey pertained to the capillaries and they were too small to see without a microscope. Microscopes had not yet been invented.

Harvey was not correct in all of his assertions however. For instance, he believed that the heart was the source of body heat and that blood, after providing heat to the distal parts of the body, returned to the heart for warming. However, any contemporary student of heart and vessel function should read Harvey.

Harvey is less well known for his embryological studies. Regardless, his studies of chick embryology were the best of his time and for many years to come. He clearly was epigenetic in view (i.e., he did not believe in preformation of a minute being in either the egg or sperm) but described the gradual development and differentiation of an individual from an essentially homogenous egg. All embryologists to this day know the aphorism ex ovo omnia (all animals from eggs).