William Harvey was a British doctor born in 1578. He studied medicine at Padua, Italy, then worked in London at the Royal College of Physicians before becoming a physician to King James I and King Charles I.
Harvey studied both animals and humans. He realised he could observe animal hearts in action and that his work would also apply to humans. Before Harvey, people thought that there were 2 kinds of blood and that they flowed through two separate systems of blood vessels (Galen’s idea). Harvey realised that Galen was wrong. He thought that the blood must circulate round the body. He published his book ‘On the motions of the heart and blood’ in 1628.
Harvey was a careful scientist who drew conclusion from methodical observation and experimentations.
Harvey’s ideas, shown in his books, gave doctors a map of how the body worked.
However, not everyone believed his theories and it took a long time before doctors used them in their treatments.