William Harvey

William Harvey (1578-1657), a late 16th early 17th century English physician, gifted humanity with one of the most important contributions to the progress of medical science by introducing quantitative methods into physiological investigations which resulted in his discoveries that the heart pumps blood through the body, and does so via a system of vessels such that the blood moves in a circle, from the heart through the arteries and back to the heart through the veins. Publishing those findings in his 1628 book, Exercitatio Anatomica de Motu Cordis et Sanguinis in Animalibus (Anatomical Exercises on the Motion of the Heart and Blood in Animals), usually referred to as De Motu Cordis, Harvey accomplished the following:

• He solved a puzzle that had unknowingly eluded Galenicized physicians up to his time — the cardinal features of the map of the movement of blood in the body — the circulation of the blood;
• He reintroduced the concept of experimentation in scientific studies, earlier introduced by Galen but lost to medicine for nearly one and a half millenia;
• He offered first use of quantitative methods in research — by estimating the volume of blood pumped by the heart each day and showing the improbability that the amount of food consumed each day, if entirely converted to blood by the liver, as blood was supposedly formed, could account for that volume; and,
• He showed that reasoning by induction — generalizing from a collection of related facts — could yield inferences aiding understanding of human physiology.