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William Harvey

2007 Schools Wikipedia Selection. Related subjects: Human Scientists

   William Harvey
   William Harvey

   William Harvey ( April 1, 1578 – June 3, 1657) was an English medical
   doctor, who is credited with being the first to correctly describe, in
   exact detail, the properties 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 which carried nourishment around the body. Although Spanish
   physician Michael Servetus discovered circulation a quarter century
   before Harvey was born, all but three copies of his manuscript
   Christianismi Restitutio were destroyed and as a result, the secrets of
   circulation were lost until Harvey rediscovered them nearly a century
   later. Harvey travelled widely in the course of his researches,
   especially to Italy, where he stayed at the Venerable English College
   in Rome.

Early life and education

   Harvey was born in Folkestone, Kent, England (the nearest Hospital to
   Folkestone (in Ashford) is named after him) to a prosperous yeoman, and
   educated at The King's School, Canterbury, at Gonville and Caius
   College, Cambridge, from which he received a B.A. in 1597, and at the
   University of Padua (also attended by Copernicus), where he studied
   under Hieronymus Fabricius, and the Aristotelian philosopher Cesare
   Cremonini graduating in 1602. He returned to England and married
   Elizabeth Browne, daughter of Lancelot Browne, a prominent London
   physician. Harvey never had children with Elizabeth. He became a doctor
   at St Bartholomew's Hospital in London (1609–43) and a Fellow of the
   Royal College of Physicians. After his time at St Bartholomew's he
   returned to Oxford and became Warden (head of house) of Merton College.
   In 1651 William Harvey donated money to the college for building and
   furnishing a library, which was dedicated in 1654. In 1656 he gave an
   endowment to pay a librarian and to present a yearly oration, which
   continues to happen in the present day in his honour. Harvey also left
   money in his will for the founding of a boys' school in his native town
   of Folkestone; opened in 1674, the Harvey Grammar School has had a
   continuous history to the present day.

New circulatory model

   Many believe that both Servetus and Descartes merely re-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.

   Fabricius, Harvey's teacher at Padua, had claimed discovery of "valves"
   in veins, but had not discovered the true use of them. The explanation
   that he had put forward did not satisfy Harvey, and thus it became
   Harvey's endeavour to explain the true use of these valves, and
   eventually, the search suggested to him the larger question of the
   explanation of the motion of blood. Harvey 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 re-circulated in a closed system.

   This clashed with the accepted model going back to Galen, who
   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 Ibn Nafis
   had been ignored.

   Harvey based most of his conclusions on careful observations recorded
   during vivisections made of various animals during controlled
   experiments, being the first person to study biology quantitatively. He
   did an experiment to see how much blood would pass through the heart
   each day. In this experiment he used estimates of the capacity of the
   heart, how much blood is expelled each pump of the heart, and the
   amount of times the heart beats in a half an hour. All of these
   estimates were all purposly low, this was so people could see the vast
   amount of blood needed to be produced in a day by the liver. He
   estimated that the capacity of the heart was 1.5 ounces, and that every
   time the heart pumps, 1/8 of that blood is expelled. This led to
   Harvey's estimate that about 1/6 of an ounce of blood went through the
   heart every time it pumped. The next estimate he used was that the
   heart beats 1000 times every half an hour, which gave 10 pounds 6
   ounces of blood in a half an hour, and when this number was multiplied
   by 48 half hours in a day he realized that the liver would have to
   produce 540 pounds of blood in a day. At this time, common thought was
   that the blood was recycled and not constantly produced.

   He proposed that blood flowed through the heart in two separate closed
   loops. One loop, pulmonary circulation, connected the circulatory
   system to the lungs. The second loop, systemic circulation, causes
   blood to flow to the vital organs and body tissue. He also observed
   that blood in veins would move readily towards the heart, but veins
   would not allow flow in the opposite direction. This was observed by
   another simple experiment. Harvey tied a tight ligature onto the upper
   arm of a person. This would cut off bloodflow from the arteries and the
   veins. When this was done, the arm below the ligature was cool and
   pale, while above the ligature it was warm and swollen. The ligature
   was loosened slightly, which allowed blood from the arteries to come
   into the arm, since arteries are deeper in the flesh than the veins.
   When this was done, the opposite effect was seen in the lower arm. It
   was now warm and swollen. The veins were also more visible, since now
   they were full of blood. Harvey then noticed little bumps in the veins,
   which he realized were the valves of the veins, discovered by an
   earlier biologist, Hieronymus Fabricius. Harvey tried to push blood in
   the vein down the arm, but to no avail. When he tried to push it up the
   arm, it moved quite easily. The same effect was seen in other veins of
   the body, except the veins in the neck. Those veins were different from
   the others - they did not allow blood to flow up, but only down. This
   led Harvey to believe that the veins allowed blood to flow to the
   heart, and the valves maintained the one way flow. Harvey further
   concluded that the heart acted like a pump that forced blood to move
   throughout the body instead of the prevailing theory of his day that
   blood flow was caused by a sucking action of the heart and liver. These
   important theories of Harvey represent two significant contributions to
   the understanding of the mechanisms of circulation.

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 Moleadult in early stages. He
   also hypothesized the existence of a mammalian egg, and dissected
   dozens of deer in the red neck 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 lifetime. 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). After his and others' attempts to cure James of his fatal
   illness failed, he became a scapegoat for that failure amidst rumours
   of a Catholic plot to kill James, but was saved by the personal
   protection of Charles I (to whom he was also personal physician, from
   1625 to 1647). He took advantage of these royal positions by dissecting
   deer from the royal parks and demonstrating the pumping of the heart on
   Viscount Montgomery's son, who had fallen from a horse when he was a
   boy, leaving a gap in his ribs, subsequently covered by a metal plate,
   which he was able to remove for Harvey. "I immediately saw a vast
   hole," Harvey wrote, and it was possible to feel and see the heart's
   beating through the scar tissue at the base of the hole.

   His research notes were destroyed in riots in London at start of the
   English Civil War. He himself went with the king on campaign, and was
   in charge of the royal children's safety at the Battle of Edgehill,
   hiding them in a hedge with them reading a book, then forced by enemy
   fire to shelter behind the Royalist lines, and at the end of the battle
   tending to dying and wounded.

   Harvey also became 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, based on the prevailing Galenic tradition,
   was 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 Rhazes. (See also: François Bernier)

Posthumous Honours

   Harvey was ranked #56 on Michael H. Hart's list of the most influential
   figures in history. Pulitzer Prize-winning historian Arthur Schlesinger
   Jr. also included him in his list of "The Ten Most Influential People
   of the Second Millennium" in the World Almanac & Book of Facts.

Later Years

   He later died of a stroke in 1657. He was seventy-nine.

Writings

     * 1628 Exercitatio Anatomica de Motu Cordis et Sanguinis in
       Animalibus
     * 1651 De Generatione

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