Harvey

William, 1578–1657. English anatomist, physiologist, and physician who first described the circulation of the blood in 1628. He understood that the interventricular septum is not porous so blood cannot pass through it. He demonstrated the volume of blood that passes unidirectionally through a segment of a peripheral vein exceeds the volume of blood within the body, so blood must recirculate. He described the organization of the fetal circulation and the transition to the postnatal organization.

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Har·vey (hahrґve) William, 1578–1657. English physician; he practiced in London and was physician to James I and Charles I. In his Exercitatio anatomica de motu cordis et sanguinis (1628), Harvey demonstrated that (1) contraction of the heart muscle coincides with the pulse as the ventricles pump blood into the aorta and pulmonary artery; (2) the pulse is produced by the arteries' filling with blood; (3) the septum is impervious; (4) venous and arterial blood are the same; and (5) the blood in the right ventricle goes through the arteries to the lungs and thence through the pulmonary veins to the left ventricle and thence through the arteries to the body whence it returns along the smaller veins to the venae cavae and then into the right ventricle—a complete circulation of the blood.