William Harvey

After his work was published, Harvey actually lost patients, as his ideas were considered eccentric. It was not until after his death that others became convinced that he was right. Marcello Malpighi (1628-1694), an Italian physician, used better quality microscopes to prove that Harvey's ideas were correct.  

Marcello Malpighi was a seventeenth century Italian physiologist who directed his microscope toward biological investigations and became one of the greatest microscopists of all time. His first publication in 1661 announced his observations on the anatomy of the frog lung. While observing dissected lung tissue, Malpighi discovered a network of tiny thin-walled microtubules, which he named capillaries. He went on to hypothesize that capillaries were the connection between arteries and veins that allowed blood to flow back to the heart.

Harvey’s ideas were about circulation were different to the previous ideas of scientists, which is why they were not accepted. Galen was a Asiatic-Greek physician who lived between the years 130 and 201. He gathered up all the medical knowledge that was known to his time. (Galen was a careful dissector and was the first to diagnose by the pulse.) The facts compiled by Galen amounted to a slim volume indeed, but it was all that mankind had until William Harvey came along, some 1300 years later. Galen had at least concluded the cardiovascular system carried blood and not air, and also managed to cast some doubt on the theories of Aristotle who thought that maybe blood arose in the liver; and the thoughts of others, that the pounding in a person's chest was but the soul speaking to us.

Harvey's work made little difference to general medical practice at the time. Blood letting continued to be a popular practice and it was not until the 20th century that doctors realised the importance of checking a patient's blood flow by taking a pulse. Harvey's work did encourage others to investigate blood circulation, e.g. the blood's role in carrying air from the lungs. His discovery of blood circulation was central to a proper understanding of the workings of the body.