Health Scientist: William Harvey
William Harvey was an English doctor and scientist. For hundred of years before Harvey’s time, doctors and scientists had known that there were two different kinds of blood vessels in the body – arteries and veins.
Harvey believed that blood leaves the heart only through the arteries and returns to it only through veins. If this is so, then the same blood circulates through the body in a closed system of blood vessels. But Harvey was never able to find any connections between the arteries and veins, although he believed they must be present. After Harvey’s death, the connections (the capillaries) were discovered.