William 
          HarveyWilliam Harvey (April 1, 1578 - June 3, 1657) was a medical doctor 
          who first correctly described in exact detail the circulatory system 
          of blood being pumped around the body by the heart. This developed the 
          ideas of René Descartes who in his Description of the Human Body 
          said that the arteries and veins were pipes and carried nourishment 
          round the body. Many believe he discovered and extended early Muslim 
          medicine especially the work of Ibn Nafis, who had laid out the principles 
          and major arteries and veins in the 13th century. 
        Early life and education
          Born in Folkestone, England, Harvey was educated at the King's School, 
          Canterbury, at Gonville and Caius College, Cambridge, from which he 
          received a BA in 1597, and at the University of Padua, where he studied 
          under Fabricius, graduating in 1602. He returned to England and married 
          Elizabeth Brown, daughter of the court physician to Elizabeth I.
        He became a doctor 
          at St. Bartholomew's hospital in London (1609-43) and a Fellow of the 
          Royal College of Physicians.
        New circulatory 
          model
          He announced his discovery of the circulatory system in 1616 and in 
          1628 published his work Exercitatio Anatomica de Motu Cordis et Sanguinis 
          in Animalibus (An Anatomical Exercise on the Motion of the Heart and 
          Blood in Animals), where, based on scientific methodology, he argued 
          for the idea that blood was pumped around the body by the heart before 
          returning to the heart and being recirculated in a closed system.
        This clashed with 
          the accepted model going back to Galen, which identified venous (dark 
          red) and arterial (brighter and thinner) blood, each with distinct and 
          separate functions. Venous blood was thought to originate in the liver 
          and arterial blood in the heart; the blood flowed from those organs 
          to all parts of the body where it was consumed. It was for exactly these 
          reasons that the work of the "heathen" Ibn Nafis had been 
          ignored.
        Embryology
          Harvey also conducted research in embryology in his later career, writing 
          On the Generation of Animals (De Generatione) in 1651. He supported 
          the Aristotelian theory that embryos formed gradually and did not possess 
          the characteristics of an adult in early stages. He also hypothesized 
          the existence of a mammalian egg, and dissected dozens of deer in the 
          King's hunting park in hopes of finding one, although he failed to do 
          so.
        Criticism of Harvey's 
          Work
        Harvey's ideas were 
          eventually accepted during his life-time. His work was attacked, notably 
          by Jean Riolan in Opuscula anatomica (1649) which forced Harvey to defend 
          himself in Exercitatio anatomica de circulatione sanguinis (also 1649) 
          where he argued that Riolan's position was contrary to all observational 
          evidence. Harvey was still regarded as an excellent doctor, he was personal 
          physician to James I (1618-25) and Charles I (1625-47) and the Lumleian 
          lecturer to the Royal College of Physicians (1615-56). Marcello Malpighi 
          later proved that Harvey's ideas on anatomical structure were correct; 
          Harvey had been unable to distinguish the capillary network and so could 
          only theorize on how the transfer of blood from artery to vein occurred.
        Even so, Harvey's 
          work had little effect on general medical practice at the time — 
          blood letting, an idea based on the incorrect theories of Galen, continued 
          to be a popular practice (and continued to be so even after Harvey's 
          ideas were accepted). Harvey's work did much to encourage others to 
          investigate the questions raised by his research, and to revive the 
          Muslim tradition of scientific medicine expressed by Nafis, Ibn Sina 
          and of course Rhazes.
        William Harvey
          (1578-1657) 
          Galen, a Asiatic-Greek physician who lived between the years 130 and 
          201 is described as having been a voluminous writer on medical and philosophical 
          subjects.1 Galen is to medicine what Ptolemy2 was to astronomy. 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 lived during the Elizabethan period of England.3 He had the good 
          fortune, upon returning from Italy where he had completed his medical 
          education, to marry the daughter of Elizabeth's physician. This connection 
          meant that Harvey did not have to work too hard at making a living, 
          thus leaving time for him to pursue medical research. By 1616 he was 
          lecturing before the College of Physicians on the circulation of the 
          blood. His notes (yes! he had extremely bad hand writing) built up into 
          a considerable mass, as he went about, through the years, cutting up 
          animals and giving lectures on his findings.4 Harvey may have realized 
          right along the importance of getting his work in print, but he was 
          in no hurry; like Copernicus, Harvey must have thought that his work 
          was never quite good enough, but, nonetheless, it was plainly an advance 
          on the accepted theories of Galen. His theories, to use own words: 
          "[It] is of so novel and unheard-of character, that I not only 
          fear injury to myself from the envy of a few, but I tremble lest I have 
          mankind at large for my enemies, so much does wont and custom, that 
          has become as another nature, and doctrine once sown and that has struck 
          deep root and rested from antiquity, influence all men." 
          And, Harvey recognized the problem with "journalism" as it 
          existed then, and, as it continues to exist today: 
          "The crowd of foolish scribblers is scarcely less than the swarms 
          of flies in the height of summer, and threatens with their crude and 
          flimsy productions to stifle us as with smoke." 
          Harvey, at the age of 50, in 1628, came quietly to the world stage when 
          he saw to the publication in Germany of a 72 page volume of his work 
          (written in Latin as were all learned articles of the day). It was at 
          the Frankfurt book fair that there stood a stack of newly printed books 
          with the title, Exercitatio Anatomica de Motu Cordis et Sanguinis in 
          Animalibus (Anatomical Exercise on the Motion of the Heart and Blood 
          in Animals), or, as it came to be known, De Motu Cordis. The earlier 
          theories were refuted and Harvey's theory was advanced and has held 
          firm ever since. (The only thing Harvey could never figure out, though 
          he recognized it took place, was how the blood was transferred over 
          from the arteries to the veins. The riddle was solved a few years after 
          Harvey's death when a professor at Bologna (Italy), Marcello Malpighi, 
          saw, through the newly-invented microscope, an instrument not available 
          to Harvey, the capillary network.) 
          As the fame of De Motu Cordis spread, the critics came at Harvey from 
          all directions. "'Twas believed by the vulgar that he was crack-brained, 
          and all the physicians were against him." For the most part Harvey 
          ignored his critics, though it should be noted that his medical practice 
          suffered. But, finally, 21 years after the initial publication of De 
          Motu Cordis, in 1649, at age of 71 (he was to live to age 79), Harvey 
          came back with a small volume where, in it, he gave his detailed replies. 
          
          The major difference between Harvey and his predecessors, was -- methodology. 
          Harvey determined to start out, so to speak, with a blank fact book 
          and distinguished it from his theory book. Nothing would go down in 
          his fact book unless tested and would readily remove it if it did not 
          bear out on a re-test. Harvey went beyond mere superficial observation; 
          and, he took deliberate steps so as not to be hampered by superstition 
          or antiquated theories. Harvey was the first to adopt the scientific 
          method for the solution of biological problems. Every true scientist, 
          since, has followed Harvey's approach. 
          I shall end this short note on William Harvey by turning to William 
          Osler: 
          "... it [De Motu Cordis] marks the break of the modern spirit with 
          the old traditions. No longer were men to rest content with careful 
          observation and with accurate description; no longer were men to be 
          content with finely spun theories and dreams, which "serve as a 
          common subterfuge of ignorance"; but here for the first time a 
          great physiological problem was approached from the experimental side 
          by a man with a modern scientific mind, who could weigh evidence and 
          not go beyond it, and who had the sense to let the conclusions emerge 
          naturally but firmly from the observations." (Attributed to Sir 
          William Osler, 1849-1919.) 
        Harvey, William 
          (1578-1657) 
        English physician 
          who, by observing the action of the heart in small animals and fishes, 
          proved that heart receives and expels blood during each cycle. Experimentally, 
          he also found valves in the veins, and correctly identified them as 
          restricting the flow of blood in one direction. He developed the first 
          complete theory of the circulation of blood, believing that it was pushed 
          throughout the body by the heart's contractions. He published his observations 
          and interpretations in Exercitatio Anatomica de Motu Cordis et Sanguinis 
          in Animalibus (1628), often abbreviated De Motu Cordis. 
        Harvey also noted, 
          as earlier anatomists, that fetal circulation short circuits the lungs. 
          He demonstrated that this is because the lungs were collapsed and inactive. 
          Harvey could not explain, however, how blood passed from the arterial 
          to the venous system. The discovery of the connective capillaries would 
          have to await the development of the microscope and the work of Malpighi. 
          He was heavily influenced by the mechanical philosophy in his investigations 
          of the flow of blood through the body. In fact, he used a mechanical 
          analogy with hydraulics. He could not, however, explain why the heart 
          beats. Furthermore, Harvey used quantitative methods to measure the 
          capacity of the ventricles. 
        Harvey was the first 
          doctor to use quantitative and observation methods simultaneously in 
          his medical investigations. In Exercitationes de Generatione Animalium 
          (On the Generation of Animals, 1651), he was extremely skeptical of 
          spontaneous generation and proposed that all animals originally came 
          from an egg. His experiments with chick embryos were the first to suggest 
          the theory of epigenesis, which views organic development as the production 
          in a cumulative manner of increasingly complex structures from an initially 
          homogeneous material.