Medicine

H

Arabic

In the 7th century ad a vast portion of the Eastern world was overrun by Arab conquerors. In Persia (now Iran), the Arabs learned of Greek medicine at the schools of the Nestorian Christians (see Nestorianism), a sect in exile from the Byzantine Empire. These schools had preserved many texts lost in the destruction of the Alexandria Library. Translations from Greek were instrumental in the development of an Arabic system of medicine throughout the Arab-speaking world. Followers of the system, known as Arabists, did much to elevate professional standards by insisting on examinations for physicians before licensure. They introduced numerous therapeutic chemical substances and excelled in the fields of ophthalmology and public hygiene.

Important among Arabist physicians was al-Razi, who was the first to identify smallpox and measles and to suggest blood as the cause of infectious diseases. Avenzoar was the first to describe the parasite causing the skin disease scabies and was among the earliest to question the authority of Galen. Maimonides wrote extensively on diet, hygiene, and toxicology, the study of chemicals and their effect on the body. Al-Quarashi, also known as Ibn al-Nafīs, wrote commentaries on the writings of Hippocrates and treatises on diet and eye diseases. He was the first to determine the pathway of blood, from the right to the left ventricle via the lungs.

I

European

In early medieval Europe, religious groups established hospitals and infirmaries in monasteries and later developed charitable institutions designed to care for the victims of vast epidemics of bubonic plague, leprosy, smallpox, and other diseases that swept Europe during the Middle Ages. The Benedictines were especially active in this work, collecting and studying ancient medical texts in their library at Monte Cassino near Salerno, Italy. St. Benedict of Nursia, the founder of the order, obligated its members to study the sciences, especially medicine. The abbot of Monte Cassino, Bertharius, was himself a famous physician.

During the 9th and 10th centuries Salerno became Europe’s center for medical care and education and was the site of the first Western school of medicine. By the 12th century other medical schools were established at the universities of Bologna and Padua in Italy, the University of Paris in France, and Oxford University in England.

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In the 13th century, medical licensure by examination was endorsed and strict measures were instituted for the control of public hygiene. Representative scientists of this period include the German scholastic St. Albertus Magnus, who engaged in biological research, and the English philosopher Roger Bacon, who undertook research in optics and refraction and was the first scholar to suggest that medicine should rely on remedies provided by chemistry. Bacon, often regarded as an original thinker and pioneer in experimental science, was strongly influenced by the authority of Greek and Arabic medicine.

The period of the Renaissance, which began at the end of the 14th century and lasted for about 200 years, was one of the most revolutionary and stimulating in the history of mankind. Invention of printing and gunpowder, discovery of America, the new cosmology of Copernicus, the Reformation, the great voyages of discovery—all these new forces were working to free science and medicine from the shackles of medieval stagnation. The fall of Constantinople in 1453 scattered the Greek scholars, with their precious manuscripts, all over Europe.

The revival of learning in Western civilizations brought great advances in human anatomy. Some resulted from the work of artists, including Italian Leonardo da Vinci, who dissected human corpses to portray muscles and other structures more accurately. Andreas Vesalius, a Belgian anatomist, clearly demonstrated hundreds of anatomical errors introduced by Galen centuries earlier. Gabriel Falliopius discovered the uterine tubes named after him (see Fallopian Tube) and diagnosed ear diseases with an ear speculum. He described in detail the muscles of the eye, tear ducts, and fallopian tubes. Italian physician Girolamo Fracastoro recognized that infectious diseases are spread by invisible so-called seeds that can reproduce themselves. He founded modern epidemiology, the study of how diseases spread. The term syphilis, applied to the virulent disease then devastating Europe, was derived from his famous poem, “Syphilis sive Morbus Gallicus” (Syphilis or Disease of Gauls, 1530). Ambroise Paré introduced new surgical techniques and helped to found modern surgery.

VII

The Dawn of Modern Medicine

The event that dominated 17th-century medicine and marked the beginning of a new epoch in medical science was the discovery of how the blood circulates in the body by the English physician and anatomist William Harvey. Harvey's “Essay on the Motion of the Heart and the Blood” (1628) established that the heart pumps the blood in continuous circulation. The Italian anatomist Marcello Malpighi advanced Harvey's work by his discovery of tiny blood vessels called capillaries, and the Italian anatomist Gasparo Aselli provided the first description of the lacteals, capillaries found in the lymphatic system. In England the physician Thomas Willis investigated the anatomy of the brain and the nervous system and was the first to describe diabetes mellitus. The English physician Francis Glisson advanced the knowledge of the anatomy of the liver, described the nutritional disorder rickets (sometimes called Glisson's disease), and was the first to prove that muscles contract when activity is performed. The English physician Richard Lower studied the anatomy of the heart, showed how blood interacts with air, and performed one of the first blood transfusions.

The French mathematician and philosopher René Descartes, who also made anatomical dissections and investigated the anatomy of the eye and the mechanism of vision, maintained that the body functioned as a machine. This view was adopted by the so-called iatrophysicists, such as Italian physician Sanctorius, who investigated metabolism, and the Italian mathematician and physicist Giovanni Alfonso Borelli, who worked in the area of physiology. Opponents of this view were the iatrochemists, who regarded life as a series of chemical processes, including Jan Baptista van Helmont, a Flemish physician and chemist, and Prussian anatomist Franciscus Sylvius, who studied the chemistry of digestion and emphasized the treatment of disease by drugs.

The English physician Thomas Sydenham, called the English Hippocrates, and later the Dutch physician Hermann Boerhaave, reestablished the significance of bedside instruction in their emphasis on the clinical approach to medicine. Sydenham carried out extensive studies on malaria and introduced the new treatment quinine, obtained from cinchona bark, into Europe in 1632. After the invention of the first compound microscope in 1590, Dutch scientist Antoni van Leeuwenhoek used this groundbreaking technology in 1676 to identify organisms later called bacteria. This was the first step toward recognition that microbes were the cause of infectious disease.

A

18th-Century Medicine

The 18th century continued to be marked by unsupported theories. The German physician and chemist Georg Ernst Stahl believed that the soul is the vital principle and that it controls organic development; in contrast, the German physician Friedrich Hoffmann considered the body a machine and life a mechanical process. These opposing theories of the vitalists and the mechanists were influential in 18th-century medicine. The British physician William Cullen attributed disease to the excess or deficiency of nervous energy; and the physician John Brown of Edinburgh taught that disease was caused by weakness or inadequate stimulation of the organism. According to his theories, known as the Brunonian system, stimulation should be increased by treatment with irritants and large dosages of drugs. In opposition to this system, the German physician Samuel Hahnemann developed the system of homeopathy late in the 18th century, which emphasized small dosages of drugs to cure disease.

Other unusual medical practices developed toward the end of the 18th century include phrenology, a theory formulated by the German physician Franz Joseph Gall, who believed that examination of the skull of an individual would reveal information about mental functions. The theory of animal magnetism developed by the Austrian physician Franz Mesmer was based on the existence of a magnetic force having a powerful influence on the human body.

Despite these unorthodox medical practices, the end of the 18th century was marked by many true medical innovations. British physicians William Smellie and William Hunter made advances in obstetrics that established this field as a separate branch of medicine. The British social reformer John Howard furthered humane treatment for hospital patients and prison inmates throughout Europe. In 1796 British physician Edward Jenner introduced vaccination to prevent smallpox. His efforts both controlled this dreaded disease and also established the science of immunization.

B

19th-Century Medicine

Many discoveries made in the 19th century led to great advances in diagnosis and treatment of disease and in surgical methods. Medicine’s single most important diagnostic tool, the stethoscope, an instrument used to detect sounds in the body such as a heart beat, was invented in 1819 by French physician René-Théophile-Hyacinthe Laënnec. A number of brilliant British clinicians studied and described diseases that today bear their names. British physician Thomas Addison discovered the disorder of the adrenal glands now known as Addison's disease; Richard Bright diagnosed the kidney disorder, Bright's disease; British physician Thomas Hodgkin described a cancer of lymphatic tissue now known as Hodgkin's disease; British surgeon and paleontologist James Parkinson described the chronic nervous system disease called Parkinson disease; and the Irish physician Robert James Graves diagnosed the thyroid disorder exophthalmic goiter, sometimes called Graves' disease.

Medicine, like all other sciences, is subject to influences from other fields of study. This was particularly true during the 19th century, renowned for its great scientific innovations. For instance, the evolutionary theory proposed by Charles Darwin in On the Origin of Species by Means of Natural Selection (1859) revived interest in the science of comparative anatomy and physiology. And the plant-breeding experiments of the Austrian biologist Gregor Johann Mendel in 1866, although initially overlooked, eventually had a similar effect in stimulating studies in human genetics (see Heredity).

German pathologist Rudolf Virchow pioneered development of pathology, the scientific study of disease. Virchow showed that all diseases result from disorders in cells, the basic units of body tissue. His doctrine that the cell is the seat of disease remains the cornerstone of modern medical science. In France, physiologist Claude Bernard performed important research on the pancreas, liver, and nervous system. His scientific studies, which emphasized that an experiment should be objective and prove or disprove a hypothesis, were the basis for the scientific method used today. Bernard's work on the interaction of the digestive system and the vasomotor system, which controls the size of blood vessels, was developed further by the Russian physiologist Ivan Petrovich Pavlov, who developed the theory of the conditioned reflex, the basis of human behaviorism.

A milestone in medical history occurred in the 1870s when French chemist Louis Pasteur and German physician Robert Koch separately established the germ theory of disease. Important in the development of this theory was the pioneering work of the American physician and author Oliver Wendell Holmes and of the Hungarian obstetrician Ignaz Philipp Semmelweis, who showed that the high rate of mortality in women after childbirth was attributable to infectious agents transmitted by unwashed hands (see Puerperal Fever).

Soon after the germ theory was recognized, the causes of such age-old scourges as anthrax, diphtheria, tuberculosis, leprosy, and plague were isolated. Pasteur developed a way to prevent rabies using a vaccine in 1885. In the last decade of the 19th century, German physician Emil von Behring and German bacteriologist Paul Ehrlich developed techniques for immunizing against diphtheria and tetanus.

New understanding of infectious diseases made surgery safer. Until the 1800s, surgeons operated in their street clothes, often without even washing their hands. Operating rooms, like other parts of hospitals, were filthy. About half of all surgery patients who survived the actual surgery typically died of infections that developed after the operation. The era of aseptic surgery, in which physicians used sterilized instruments and techniques to avoid infecting patients, was heralded by British surgeon and biologist Joseph Lister. With his introduction of an effective antiseptic, carbolic acid, Lister was able to successfully reduce mortality from wound infection (see Antiseptics). Rubber gloves were first worn during surgery in 1890, and gauze masks in 1896.

Another great advance in surgery came with the discovery of anesthesia. Until the 19th century, doctors used alcohol, opium, and other drugs to relieve pain during surgery. These medications could sometimes dull pain but could never completely mask it—patients often suffered from shock and died during surgery. In the United States, physician Crawford Long discovered the anesthetic effects of ether in 1842, and the dentist William Morton used ether in a tooth extraction in 1846. Ether and other anesthetics reduced surgical mortality and enabled surgeons to perform longer, more complicated operations.

A new tool for diagnosing internal diseases became available in 1895 when German scientist Wilhelm Roentgen discovered X rays. The Danish physician Niels Ryberg Finsen developed an ultraviolet-ray lamp, which led to an improved prognosis for some skin diseases (see Ultraviolet Radiation). In 1898 in France, Marie and Pierre Curie discovered radium, which was later used to treat cancer.

In 1898 British physician Ronald Ross proved the role of the mosquito as a carrier of the malarial parasite, a disease that has been widespread and sometimes fatal for most of human history. In 1900 United States Army physician Walter Reed and his colleagues, acting on a suggestion made by the Cuban biologist Carlos Juan Finlay, demonstrated that the mosquito is the carrier of yellow fever. This finding lead to better sanitation and mosquito control, resulting in the virtual elimination of this disease from Cuba and other areas.