veterinary medicine, diagnosis and treatment of diseases of animals. An early interest in animal diseases is found in ancient Greek writings on medicine. Veterinary medicine began to achieve the stature of a science with the organization of the first school in the field in Lyons, France, in 1761, followed soon by similar schools in other parts of Europe. In the United States, veterinary schools came into existence about the time of the Civil War, and there are now a number of accredited schools of veterinary medicine affiliated with colleges and universities. In 1884 the Bureau of Animal Industry was established in the U.S. Dept. of Agriculture to deal with animal disease problems in the fast-growing livestock industry. Veterinary research has made important contributions to medical science in general. Vaccination methods devised by Louis Pasteur and Robert Koch for animals were found effective for humans also. Veterinarians inaugurated the inspection of meat and milk to prevent the spread of tuberculosis. The development since World War II of live-virus and modified live-virus vaccines and of antibiotics, sulfonamides, and other biological products has brought about a marked change in veterinary medicine. An important innovation was the mass immunization of poultry through sprays, dusts, and agents added to drinking water. Many animal diseases hitherto considered incurable can now be prevented or controlled by these new therapeutic agents, and this in turn has greatly increased the output of livestock and poultry products.

tropical medicine, study, diagnosis, treatment, and prevention of certain diseases prevalent in the tropics. The warmth and humidity of the tropics and the often unsanitary conditions under which so many people in those areas live contribute to the development and dissemination of many infectious diseases and parasitic infestations. Much has been achieved in combating such typical tropical diseases as yellow fever, amebic dysentery, and filariasis (elephantiasis). Better public health measures and therapeutic agents have assisted in the fight. The World Health Organization and philanthropic foundations have worked with local and international efforts to bring about medical advances. The deployment of American troops in malaria-infested regions spurred the search for more efficient synthetic antimalarial drugs. DDT, introduced in World War II to eradicate the malaria-carrying mosquito, has been found to have lingering toxic effects in the environment, and the persistent use of DDT in China for rice pests has produced DDT-resistant mosquitoes that now carry malaria. Resistance of the malarial parasite to chloroquine and Fansidar, the most widely used drugs for the protection of travelers in the tropics, has made both drugs virtually useless in most of Asia, Africa, and South America. A new drug, mefloquine, is effective in some areas but has many serious side effects. Current research is directed at making a vaccine against malaria. There have also been advances against hookworm, leprosy, and other tropical maladies. The emergence in central Africa of the Ebola virus, which exists in an as yet unknown host and is fatal to 50%-90% of those infected, has been especially challenging to medical personnel in underequipped hospitals where outbreaks have occurred.

sports medicine, branch of medicine concerned with physical fitness and with the treatment and prevention of injuries and other disorders related to sports. Knee, leg, back, and shoulder injuries; stiffness and pain in joints; tendinitis; "tennis elbow"; and dehydration are some common conditions that may be involved. Treatment and prevention include exercise programs for increasing strength, flexibility, and endurance; physical therapy; fitness tests; advice concerning nutrition and fluid replacement; and use of protective equipment. Surgery may be needed to treat some injuries. Sports medicine is also concerned with the abuse of so-called performance-enhancing drugs, such as anabolic steroids. The specialty was initially practiced primarily by physicians associated with professional sports teams, but with increased interest in amateur sports and physical fitness programs in the 1970s and 1980s, it grew rapidly.

space medicine, study of the medical and biological effects of space travel on living organisms. The principal aim is to discover how well and for how long humans can withstand the extreme conditions encountered in space, as well as how well they can readapt to the earth's environment after a space voyage. The medically significant aspects of space travel include weightlessness, strong inertial forces experienced during liftoff and reentry, radiation exposure, absence of the earth's day-and-night cycle, and existence in a closed ecological environment. Less critical factors are the noise, vibration, and heat produced within the spacecraft. On longer space flights, the psychological effects of isolation and living in close quarters have been a concern, especially among multinational crews with inherent differences in language and culture.

A large body of useful medical data on the effects of a prolonged U.S. space flight was obtained during the Skylab program of the early 1970s and from several medical missions of the space shuttles Challenger and Columbia. The Soviet Union's Soyuz program began Russia's experience with long stays in space; the current record of nearly 439 days was set by Russian cosmonaut Valery Polyakov (Jan. 8, 1994-Mar. 22, 1995) on the space station Mir. With the change in the international political climate in the 1990s, the two countries began to cooperate in life-science research that combined the more sophisticated diagnostic and monitoring equipment of the NASA missions with the greater long-term-stay experience of the Russians. In May, 1995, the Spektr module, containing U.S. medical and research equipment, was added to the Mir. A few months later, American physician-astronaut Norman E. Thagard broke the former U.S. record of 84 continuous days in space when he spent 111 days on the Russian space station.

There have been many indirect benefits to medicine from space science. The need to maintain close watch over the physiological conditions of astronauts has spurred the development of improved means for electronically monitoring essential body functions. The development of programmable heart pacemakers, implantable drug administration systems, magnetic resonance imaging (MRI), and computerized axial tomography (CAT) all depended to some extent on knowledge gained from the space program. Studies of how astronauts would walk in the moon's weak gravitational field led to a deeper understanding of human locomotion.

See also aviation medicine; space science.

Medically Significant Aspects of Space Flight

Weightlessness

Of all the medically significant conditions experienced in space flight, weightlessness has the most drastic effects; moreover, it will be impossible to eliminate this aspect of space travel unless large space stations can be constructed that produce artificial gravity, as by rotating. Because life evolved under the constant influence of gravity, the effects of weightlessness even on the cellular level have been a concern. It was at first feared that a human being in space might lose all coordination and become completely incapacitated. While the human body does appear to adjust fairly quickly in a state of weightlessness, associated problems do occur, often causing difficulties only upon return to earth. Problems include space adaptation syndrome (nausea, motion sickness, and sensory disorientation during the first few days), weakened immune defenses, loss of bone mass, loss of muscle mass (including loss of heart muscle), and space anemia, which results as the number of red cells decreases. Russian astronauts undergo strenuous exercise routines twice daily to try and maintain bone and large muscle mass. Nevertheless, some have had to be carried on stretchers when they first return to earth.

Inertial Forces

Inertial forces due to acceleration are experienced only during liftoff and reentry, but the consequences can be traumatic. The circulatory system is most strongly affected; deprivation of blood to the brain causes dimming of vision and sometimes loss of consciousness. However, lying on a body-contoured couch, astronauts have survived inertial forces eight times stronger than normal gravity.

Ionizing Radiation

In space the astronauts are exposed to ionizing radiation from particles trapped in the earth's magnetic field, from solar flares, and from the onboard nuclear reactors that help power the spacecraft. This radiation can produce deleterious effects, ranging from nausea and lowered blood count to genetic mutations and leukemia. Protective shielding, shielding chemicals, and careful monitoring of the doses of radiation received by each astronaut have been used to reduce radiation exposure to acceptable levels.

Absence of Day and Night

The absence of the earthly cycle of day and night during space travel produces subtle effects, both physiological and psychological. The period from sunrise to sunset in a quickly orbiting space shuttle may be as little as 11∕2 hours long. All body rhythms, such as heartbeat, respiration, and changes in body temperature, are regulated by biological clocks (see biorhythm). These rhythms are related to human patterns of sleep and wakefulness, which in turn are based on the alternation of day and night. On most flights, adherence to "home" schedules maintains normal human cycles.

A Closed Environment

In the closed environment of the spacecraft care must be taken to prevent the buildup of toxic material to dangerous levels; this is accomplished by recycling waste material. The nature of the artificial atmosphere astronauts breathe is an important biomedical consideration. Ideally, this atmosphere would be identical in composition and pressure to the earth's atmosphere. Any alteration involves the risk of decompression sickness. The space shuttle uses a pure oxygen atmosphere or a mixture of oxygen and nitrogen.

socialized medicine, publicly administered system of national health care. The term is used to describe programs that range from government operation of medical facilities to national health-insurance plans. In 1948, Great Britain passed the National Health Service Act that provided free physician and hospital services for all citizens. The system was later amended, now charging a small fee for the filling of prescriptions and the purchasing of eyeglasses and dentures; it is funded jointly by a health-insurance tax and by the national treasury. Doctors are salaried by the government and receive an additional allotment per patient and for the performance of special services. Sweden maintains a compulsory health-insurance plan that provides for income compensation, hospital treatment, most of the physician's fee, and part of the cost of medicines. Maternity benefits are provided for expectant women. A large percentage of Israel's medical care is provided by the Histadrut, the national labor union. A number of private welfare organizations also provide care, and the armed forces maintain a number of military hospitals whose services are widely used since many citizens of Israel are military veterans. Canada has a federally sponsored system of medical insurance with voluntary participation on the part of each province; the system is funded by taxes and contributions from the government. The United States is the only major Western country without some form of socialized medical care. However, it does sponsor Medicare, a federally administered program for those over 65, and Medicaid, a federally funded program of medical care for the poor that is administered by the individual states. Veterans have access to Veterans Health Administration facilities; care is free or partially subsidized, depending on whether injuries and disabilities are service connected.

psychosomatic medicine, study and treatment of those emotional disturbances that are manifested as physical disorders. The term psychosomatic emphasizes essential unity of the psyche and the soma, a combination rooted in ancient Greek medicine. Common disorders caused at least partly by psychological factors include childhood asthma, certain gastrointestinal problems, hypertension, endocrine disturbances, diabetes, and possibly even heart disease. In most psychosomatic conditions there is some interaction between psychological factors and physiological predisposition to the illness. Sigmund Freud, at the end of the 19th cent., laid the scientific groundwork for psychosomatic study, with his theoretical formulations based on new methods of treating hysteria. His methods were reinforced by the psychobiology of the American psychiatrist Adolf Meyer and the research of the American physiologist W. B. Cannon on the physiological effects of acute emotion. The treatment of psychosomatic ailments may involve a medical regimen as well as some form of psychotherapy for the patient. In recent years, psychosomatic medicine has been subsumed under the broader field of behavioral medicine, which includes the study of a wider range of physical ailments. Understanding the psychological causes of various ailments is crucial: studies suggest that a large percentage of deaths are rooted in behavior. In the 1960s, concepts related to conditioning gained prominence, as researchers found that humans and animals could learn to control their autonomic nervous system responses, usually involved in psychosomatic complaints. Emerging from this research came the technique of biofeedback that provides individuals with information concerning their own physiological responses, which they may begin to alter through conscious techniques of control. The newest area of research related to psychosomatic medicine has been called psychoneuroimmunology, the study of the interactions of the endocrine system, central nervous system, and immune system. Researchers believe that studies of these biological systems can help to show how an individual becomes vulnerable to illness.

preventive medicine, branch of medicine dealing with the prevention of disease and the maintenance of good health practices. Until recently preventive medicine was largely the domain of the U.S. Public Health Service or state and local health departments, but it has become an important consideration of health maintenance organizations, private practitioners, and other health care providers. Preventive medicine encompasses such activities as research into causes of disease; vaccination against those diseases for which the causes are known, e.g., poliomyelitis, influenza, and measles; studies of environmental deterrents to health; and instruction in public health and hygiene. See also eugenics.

patent medicine, packaged drugs that can be obtained without prescription; the term was formerly used to describe quack remedies sold by peddlers. Patent, or proprietary, medicines are advertised to the public by trade name, purport to be effective against minor disorders and symptoms, and are packaged with directions for use. Antiseptics, analgesics, some sedatives, laxatives, and antacids, cold and cough medicines, and various skin preparations are included in the group. Sale of proprietary medicines is regulated by the Food and Drug Administration, which evaluates preparations as to their safety and effectiveness.

medicine man, among Native Americans and other traditional peoples as far back as Paleolithic times, a person believed to possess supernatural healing powers. Like the shaman the medicine man was a specialist in spiritual healing. In some groups, women could assume an analogous role. The medicine man was often accorded many powers, including the ability to inflict pain, promote fertility, and secure good hunting and fishing. Most Native Americans typically regarded illness as resulting from the entry of malignancy into the body, or the departure of the soul from a body—through violation of a taboo or through the activities of a sorcerer from an enemy tribe. The medicine man strove through his ritual to remove or cast out the illness from the patient, or to induce the soul to return to a patient's body. The rituals might involve a variety of techniques (e.g., bloodletting, application of herbs, or the suction of the malignancy from the patient's body). Some traditional herbal remedies were undoubtedly efficacious; other practices, though deceptive, may have been of psychological benefit to the patient.

medicine, the science and art of treating and preventing disease.

History of Medicine

Ancient Times

Prehistoric skulls found in Europe and South America indicate that Neolithic man was already able to trephine, or remove disks of bone from, the skull successfully, but whether this delicate operation was performed to release evil spirits or as a surgical procedure is not known. Empirical medicine developed in ancient Egypt, and involved the use of many potent drugs still in use today, such as castor oil, senna, opium, colchicine, and mercury. In spite of their skill in embalming, however, the Egyptians had little knowledge of anatomy.

In Sumerian medicine the Laws of Hammurabi established the first known code of medical ethics, and laid down a fee schedule for specific surgical procedures. In ancient Babylonia, every man considered himself a physician and, according to Herodotus, gave advice freely to the sick man who was willing to exhibit himself to passersby in the public square. The Mosaic Code of the Hebrews indicated concerns with social hygiene and prevention of disease by dietary restrictions and sanitary measures.

Although ancient Chinese medicine was also influenced adversely by the awe felt for the sanctity of the human body, the Nei Ching, attributed to the emperor Huang-Ti (2698-2598 B.C.), contains a reference to a theory of the circulation of the blood and the vital function of the heart that suggests familiarity with anatomy. In addition, accurate location of the proper points for the traditional Chinese practice of acupuncture implies some familiarity with the nervous and vascular systems. The Chinese pharmacopoeia was the most extensive of all the older civilizations. The Hindus seem to have been familiar with many surgical procedures, demonstrating skill in such techniques as nose reconstruction (rhinoplasty) and cutting for removal of bladder stones.

In Greek medicine the impetus for the rational approach came largely from the speculations of the pre-Socratic philosophers and such philosopher-scientists as Pythagoras, Democritus, and Empedocles. Hippocrates, the father of Western medicine, taught the prevention of disease through a regimen of diet and exercise; he emphasized careful observation of the patient, the recuperative powers of nature, and a high standard of ethical conduct, as incorporated in the Hippocratic Oath. By the 4th cent. B.C., Aristotle had already stimulated interest in anatomy by his dissections of animals, and work in the 3d cent. B.C. on human anatomy and physiology was of such high quality that it was not equaled for fifteen hundred years.

The Romans advanced public health and sanitation through the construction of aqueducts, baths, sewers, and hospitals. The encyclopedic writings of Galen constitute a final synthesis of the medicine of the ancient world. Revered by Arabic and Western physicians alike, his concepts stood virtually unchallenged until the 16th cent. Unfortunately, his prolific researches on anatomy and physiology were not invariably accurate, and reliance on them impeded subsequent progress in anatomy.

The Middle Ages

With the destruction or neglect of the Roman sanitary facilities, there followed a series of local epidemics that culminated many centuries later in the great plague of the 14th cent. known as the Black Death. During the Middle Ages certain monastic libraries, notably those at Monte Cassino, Bobbio, and St. Gall, preserved a few ancient medical manuscripts, and Arab and Jewish physicians such as Avicenna and Maimonides continued medical investigation.

The first real light on modern medicine in Europe came with the translation of many writings from the Arabic at Salerno, Italy, and through a continuing trade and cultural exchange with Byzantium. By the 13th cent. there were flourishing medical schools at Montpellier, Paris, Bologna and Padua, the latter being the site of production of the first accurate books on human anatomy. At Padua, Vesalius proved that Galen had made anatomical mistakes. Prominent among those who pursued the new interest in experimental medicine were Paracelsus, Ambroise Paré, and Fabricius, who discovered the valves of the veins.

The Birth of Modern Medicine

In the 17th cent. William Harvey, using careful experimental methods, demonstrated the circulation of the blood, a concept that met with considerable early resistance. The introduction of quinine marked a triumph over malaria, one of the oldest plagues of mankind. The invention of the compound microscope led to the discovery of minute forms of life, and the discovery of the capillary system of the blood filled the final gap in Harvey's explanation of blood circulation.

In the 18th cent. the heart drug digitalis was introduced, scurvy was controlled, surgery was transformed into an experimental science, and reforms were instituted in mental institutions. In addition, Edward Jenner introduced vaccination to prevent smallpox, laying the groundwork for the science of immunization.

The 19th cent. saw the beginnings of modern medicine when Pasteur, Koch, Ehrlich and Semmelweis proved the relationships between germs and disease. Other invaluable developments included the use of disinfection and the consequent improvement in medical, particularly obstetrical, care; the use of inoculation; the introduction of anesthetics in surgery (see anesthesia); and a revival of better public health and sanitary measures. A significant decline in maternal and infant mortality followed.

Modern Medicine

Medicine in the 20th cent. received its impetus from Gerhard Domagk who discovered the first antibiotic, sulfanilamide, and the groundbreaking advancements in the use of penicillin. Further progress has been characterized by the rise of chemotherapy, especially the use of new antibiotics; increased understanding of the mechanisms of the immune system (see immunology) and the increased prophylactic use of vaccination; utilization of knowledge of the endocrine system to treat diseases resulting from hormone imbalance, such as the use of insulin to treat diabetes; and increased understanding of nutrition and the role of vitamins in health.

In Mar., 1953, at the Univ. of Cambridge, England, Francis Crick, age 35, and James Watson, age 24, announced "We have discovered the secret of life." Indeed, they had unraveled the chemical structure of the fundamental molecule of heredity, deoxyribonucleic acid (DNA), giving science and medicine the basis for molecular genetics and leading to a continuing revolution in modern medicine.

Much medical research is now directed toward such problems as cancer, heart disease, AIDS, reemerging infectious diseases such as tuberculosis and dengue fever, and organ transplantation. Currently, the largest worldwide study is the Human Genome Project, which will identify all hereditary traits and body functions controlled by specific areas on the chromosomes. Gene therapy, the replacement of faulty genes, offers possible abatement of hereditary diseases. Genetic engineering has led to the development of important pharmaceutical products and the use of monoclonal antibodies, offering promising new approaches to cancer treatment. The discovery of growth factors has opened up the possibility of growth and regeneration of nerve tissues.

With the surge of general and specialized medical knowledge, the educational requirements of the medical profession have increased. In addition to the four-year medical course and the general hospital internship required almost everywhere, additional years of study in a specialized field are usually required. Similar progress and increased requirements in education are reflected in ancillary professions such as nursing.

Modern Health Care Management

Modern medicine, characterized by growing specialization and a complex diagnostic and therapeutic technology, faces problems in the allocation of capital and personnel resources. Some authorities advocate an increase in the use of paramedical personnel to supervise the care of individuals with common, chronic, or terminal illnesses, leaving the physician in charge of treating curable disease. Others emphasize the physician's responsibility to help patients and families in the overall management of their health problems, many of which are thought to reflect the social ills of living in an urban, industrialized society.

In some countries, such as Great Britain, medical care is under government control and is available virtually without charge to all. In the United States, medical practice is characterized by a patchwork mixture of government and private control. The Kefauver-Harris amendments to the federal Food, Drug, and Cosmetic Act of 1962 empower the Food and Drug Administration to require stricter testing and licensing of new drugs. There have also been federal, state, and local programs for mass vaccination and other public health programs. The Medicare program, enacted in 1965, provides subsidized hospital and nursing-home care for persons over 65 and, with the Hill-Burton Act, provides funds for state aid to the medically indigent (Medicaid).

A wide variety of private medical insurance plans are also available to those who can afford them, and many employers pay all or part of their employees' health insurance premiums. In addition, health maintenance organizations (HMOs), or group practice plans, are designed to promote disease prevention and reduce medical expenditures.

internal medicine, branch of medicine concerned with nonsurgical remedies for diseases of the internal organs. While the internist is trained to diagnose and treat all pathologies of the various internal organs and systems, he may specialize in a particular subbranch of the discipline, such as cardiology, the treatment of heart ailments, or gastroenterology, the treatment of diseases and disorders of the digestive system.

holistic medicine, system of health care based on a concept of the "whole" person as one whose body, mind, spirit, and emotions are in balance with the environment. Stressing personal responsibility for health, a holistic approach may include conventional medicine and various nontraditional methods of diagnosis and therapy, e.g., acupuncture, biofeedback, faith healing, folk medicine, megavitamin therapy, meditation, and yoga. Patients are encouraged to establish self-regulated regimes to control such illness-related factors as poor diet, smoking, alcohol intake, and stress. Surgery and prescription drugs are generally avoided. See also alternative medicine.

herbal medicine, use of natural plant substances (botanicals) to treat and prevent illness. The practice has existed since prehistoric times and flourishes today as the primary form of medicine for perhaps as much as 80% of the world's population. Over 80,000 species of plants are in use throughout the world. Along with acupuncture, herbal medicine is considered primary health care in China, where it has been in documented use for over 2,500 years.

Herbs may be used directly as teas or extracts, or they may be used in the production of drugs. Approximately 25% of the prescription drugs sold in the United States are plant based. Many more herbal ingredients are present in over-the-counter drugs, such as laxatives. Medicines that come from plants include aspirin from willow bark (Salix species) and digitalis from foxglove (Digitalis purpurea).

Scientific interest in herbal medicine in the United States has lagged behind that in the countries of Asia and W Europe; in Germany, for example, one third of graduating physicians have studied herbal medicine, and a comprehensive therapeutic guide to herbal medicines has long been published there. Nonetheless, millions of people in the United States use herbal products to treat a wide variety of ailments or to enhance health. Among the more popular remedies used are ginseng, to increase stamina and as a mild sedative; St.-John's-wort, for mild depression; echinacea, to aid the immune system and alleviate colds; kava, to calm anxiety and treat insomnia; saw palmetto, for enlarged prostate; and ginkgo biloba, to improve short-term memory (see ginkgo). Some people have used botanicals in an attempt to stave off serious illnesses such as AIDS.

This widespread use has prompted demands that herbal remedies be regulated as drugs to insure quality standards. The U.S. Food and Drug Administration (FDA) can require a clinical trial on any herb that has a health claim on its label, but medical testing, which is geared toward observing a particular active component, is difficult to apply to herbs, which may have many interacting ingredients. Debate over botanicals' validity and safety as medicines and over the appropriate degree of government regulation continues. The Dietary Supplement Health and Education Act, passed in 1994, reclassified herbs as dietary supplements rather than food additives. It forbids unreasonable health claims by the manufacturers, but makes it the FDA's responsibility to prove that a marketed product is unsafe. (In contrast, in prescription and over-the-counter drugs, it is the manufacturer's responsibility to prove safety and effectiveness before a drug can be marketed.)

Another concern surrounding herbal medicine is the availability of wild plants for a growing market; it is feared that the limited supplies of known wild herbs are being threatened by overharvesting and habitat loss. The potential of isolating beneficial drugs from plants, however, has prompted large pharmaceutical companies to contribute to the conservation of the tropical rain forest. Biologists have called for more careful study of medicinal plants, especially regarding their capacity for sustainable harvesting and the effects of cultivation on their efficacy as medicaments.

forensic medicine: see medical jurisprudence.

folk medicine, methods of curing by means of healing objects, herbs, or animal parts; ceremony; conjuring, magic, or witchcraft; and other means apart from the formalized practice of medical science. In nearly all ancient and preliterate societies disease and death were and are attributed to the workings of malevolent beings, spirits, or forces. Complex rituals and medicinal applications were devised to heal these ills. Many such cures coincide with what modern research has proved effective. Taking castor oil has been advocated by sailors for centuries and is known today to be the source of essential vitamins; the age-old successful application of bread mold and soil fungi to infected areas corresponds to the antibiotic practice of modern medicine. There remains a widespread belief in the curative powers of certain plants or animal parts shaped or colored like the diseased part of the body: hence, red poppies for blood disorder, spotted plants for skin eruptions, and trefoil plants for heart trouble. Preventive medicine and ritual to produce sickness in one's enemies have also been popular. Native Americans of South and Central America, among others, perform purification ceremonies and hold festivals for cleansing and to ward off the evil eye. Medicine men, shamans, and other doctors credited with magical powers generally massage, draw liquid off by suction, or blow upon the diseased area. They recite ancient formulas and incantations to cure or banish illness, both physical and mental. In all cultures most medicinal lore is handed down by word of mouth from generation to generation. When written down, it formed the beginnings of medical science. In the United States in the 1960s and 70s, there occurred an enormous expanding interest in folk remedies, herbal medicines, vitamins, and so-called health foods and organic foods free of chemical pesticides and other pollutants. As a result the production of such foods became a growing business enterprise. A new surge in the sales of herbal remedies to treat minor ailments and enhance health took place in the 1990s. See also herbal medicine.

aviation medicine, scientific study of the biological effects of aviation, especially on human beings. Although aviation medicine is concerned with such problems as the spread of diseases by persons traveling by air and the harmful effects of noise and air pollution, its principal concern is with stresses applied to the passengers or crew of aircraft in flight. These stresses can include exposure to extreme temperatures, large inertial forces occurring when an aircraft undergoes acceleration, oxygen deprivation, and air sickness, as well as pilot fatigue and psychological disturbances. As the biological problems of space flight exceed considerably those of atmospheric flight, aviation medicine has become a special branch of space medicine, the latter study having largely absorbed the former.

alternative medicine, the treatment and prevention of disease by techniques that are regarded by modern Western medicine as scientifically unproven or unorthodox. The term alternative medicine can encompass a wide range of therapies, including chiropractic, homeopathy, acupuncture, herbal medicine, meditation, biofeedback, massage therapy, and various "new age" therapies such as guided imagery and naturopathy. Although many alternative therapies have long been widely employed in the treatment of disease, the scientifically oriented modern medical establishment has typically been skeptical about, and sometimes strongly opposed to, their use. Despite this, Americans spend billions of dollars on alternative treatments each year. In 1993 the U.S. National Institutes of Health established the Office of Alternative Medicine to examine the merits of such techniques. See also holistic medicine.

aerospace medicine: see aviation medicine; space medicine.

Medicine Hat, city (1991 pop. 43,625), SE Alta., Canada, on the South Saskatchewan River. It is the center of a farming and ranching area. Natural-gas deposits are exploited. There are light industries and glassblowing and rubber plants.

Medicine Bow Mountains, outlying eastern range of the Rocky Mts., SE Wyo. and N Colo. It extends from Medicine Bow town, Wyo., NW of Laramie, southward c.100 mi (160 km) to Cameron Pass, Colo. Peaks include Medicine Bow Peak (12,013 ft/3,662 m) and Elk Mt. (11,156 ft/3,400 m). Much of the area is in Medicine Bow National Forest.

Medical field dealing with animals and with diseases that are transmissible between animals and humans. It was practiced as a specialty in ancient Egypt and Babylonia; the first veterinary schools in Europe were founded in the mid-18th century. Veterinarians practice internal medicine, surgery, and preventive medicine, using the same techniques used on humans. They serve worldwide in private and corporate clinical practice, academic programs, private industry, government service, public health, and military services. Many specialize in either small animals (pets) or large ones (livestock); a few specialize in wild animals.

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Science of diseases seen primarily in tropical or subtropical climates. It arose in the 19th century when European colonial doctors encountered infectious diseases unknown in Europe. The discovery that many tropical diseases (e.g., malaria, yellow fever) were spread by mosquitoes led to discovery of other vectors' roles (see sleeping sickness, plague, typhus) and to efforts to destroy vector breeding grounds (e.g., by draining swamps). Later, antibiotics came to play an increasingly important role. Research institutes and national and international commissions were organized to control common tropical illnesses, at least in areas with Europeans. As colonies became independent, their governments took over most of these efforts, with help from the World Health Organization and the former colonizing countries.

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Medical and paramedical supervision and treatment of athletes. It has four aspects. Preparation (conditioning) uses diet, exercises, and monitoring of practice sessions to improve performance. Prevention identifies any predisposition to injury or illness and covers warmup, stretching, and design and use of protective equipment. Many surgical techniques developed in sports medicine, particularly for knee injuries, are now used for the general population. Rehabilitation (see physical medicine and rehabilitation) prepares an injured or ill athlete to return to activity after initial treatment.

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Branch of medicine, pioneered by Paul Bert, dealing with atmospheric flight (aviation medicine) and space flight (space medicine). Intensive preflight simulator training and attention to design of equipment and spacecraft promote the safety and effectiveness of humans exposed to the stresses of flight and can prevent some problems. The world's first unit for space research was established in the U.S. in 1948. Physicians trained in aerospace medicine are known as flight surgeons.

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or physiatry or physical therapy or rehabilitation medicine

Medical specialty treating chronic disabilities through physical means to help patients return to a comfortable, productive life despite a medical problem. Its objectives are pain relief, functional improvement or maintenance, training in essential activities, and functional testing of areas such as strength, mobility, breathing capacity, and coordination. Physical medicine may use diathermy, hydrotherapy, massage, exercise, and functional training. The last can mean learning to work with a guide dog or a prosthesis or learning new ways to carry out everyday activities with a limb missing, sometimes by using assistive devices. Physician specialists head rehabilitation teams including a physical therapist, rehabilitation engineer, rehabilitation nurse, psychological counselor, and sometimes a respiratory or speech therapist. Seealso occupational therapy; orthopedics.

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Efforts toward disease prevention in the community and the individual. It covers patient interviews and testing to detect risk factors; sanitary measures in homes, communities, and medical facilities; patient education; and diet and exercise programs as well as preventive drugs and surgery. It has three levels: primary (e.g., prevention of coronary heart disease in a healthy person), secondary (e.g., prevention of heart attack in a person with heart disease), and tertiary (e.g., prevention of disability and death after a heart attack). The first is by far the most economical. Important advances in preventive medicine include vaccination (see vaccine), antibiotics, diagnostic imaging, and recognition of psychological factors. Seealso epidemiology, immunology, industrial medicine, quarantine.

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Health-care profession founded by the U.S. physician Andrew Taylor Still (1828–1917) as a reform movement against the rather primitive 19th-century drugs and surgical techniques. It emphasizes the relationship between musculoskeletal structure and organ function. Osteopathic physicians learn to recognize and correct structural problems through manipulative and other therapies. Osteopathic hospitals provide general or specialized health care, including maternity and emergency care.

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or occupational medicine

Branch of medicine dealing with workers' health and the prevention and treatment of diseases and injuries in the workplace. Workplace hazards include exposure to dangerous materials including asbestos and coal dust, radiation exposure, and machinery capable of causing injuries ranging from minor to life-threatening. Industrial medical programs mandate protective devices around machines' moving parts, proper ventilation of work areas, use of less toxic materials, containment of production processes, and protective equipment and clothing. Good industrial medical programs improve labour-management relations, increase workers' overall health and productivity, and reduce insurance costs.

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Medical specialty using radioactive elements or isotopes for diagnosis and treatment of disease. A radioisotope is introduced into the body (usually by injection). The radiation it emits, detected by a scanner and recorded, reflects its distribution in different tissues and can reveal the presence, size, and shape of abnormalities in various organs. The isotopes used have short half-lives and decay before radioactivity causes any damage. Different isotopes tend to concentrate in particular organs (e.g., iodine-131 in the thyroid). Radioactive substances are also implanted to treat small, early-stage cancers. This yields a slow, continuous dose that limits damage to normal cells while destroying tumour cells. Seealso computerized axial tomography; diagnostic imaging; positron emission tomography; radiation therapy; radiology.

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Priestly healer or shaman, especially among the American Indians. The medicine man (often a woman in some societies) commonly carries a kit of objects such as feathers, stones, or hallucinogenic plants that have magical associations. The work of healing often involves the extraction—by sucking, pulling, or other means—of offending substances from the patient's body. Singing, recitation of myths, and other ceremonies often accompany the healing rite.

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Set of scientific fields related to prevention, diagnosis, and treatment of disease and maintenance of health, practiced in doctors' offices, health maintenance organization facilities, hospitals, and clinics. In addition to family practice, internal medicine, and specialties for specific body systems, it includes research, public health, epidemiology, and pharmacology. Each country sets its own requirements for medical degrees (M.D.'s) and licenses. Medical boards and councils set standards and oversee medical education. Boards of certification have stringent requirements for physicians seeking to practice a specialty and stress continuing education. Advances in therapy (see therapeutics) and diagnosis have raised complex legal and moral issues in areas such as abortion, euthanasia, and patients' rights. Recent changes include treating patients as partners in their own care and taking cultural factors into consideration.

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Medical specialty dealing with the entire patient rather than a particular organ system, covering diagnosis and medical (rather than surgical) treatment in adults. Its development began in the 17th century with Thomas Sydenham's concept of disease, but until disease-specific therapies were developed in the 20th century, internists could do little to treat diseases. As more specific treatments became available, medical knowledge increased, and subspecialties in specific organ systems were defined, internal medicine became recognized as a specialty.

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Doctrine of prevention and treatment that emphasizes looking at the whole person—body, mind, emotions, and environment—rather than a single function or organ. It promotes use of a wide range of health practices and therapies, including acupuncture, homeopathy, and nutrition, stressing “self-care” with traditional commonsense essentials. In the extreme, it may accord equal validity to a wide range of health-care approaches, some incompatible and not all scientific. It does not ignore mainstream Western medical practices but does not see them as the only effective therapies. Seealso alternative medicine.

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Science of applying medical knowledge to legal questions, recognized as a specialty since the early 19th century. Its primary tool has always been the autopsy, to identify the dead (e.g., plane-crash victims) or determine cause of death, which can significantly affect trials dealing with insurance and inheritance. Forensic psychiatry determines the mental health of an individual about to stand trial. Forensic genetics allows paternity to be determined and can identify blood or other tissue samples as coming from a particular person (see DNA fingerprinting). Forensic toxicology, concerned with such topics as intentional poisonings and drug use, is increasingly important in cases of industrial and environmental poisoning.

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or family medicine or general practice

Field of medicine that stresses comprehensive primary health care, emphasizing the family unit. Practitioners must be familiar to some degree with medical specialties and, especially in health maintenance organizations, are now often gatekeepers who refer patients to specialists when necessary. Once virtually the only kind of medicine, family practice has been defined as a separate field only since increasing specialization in medicine led to a shortage of practitioners. A 1963 World Health Organization report stressing the need for medical education to focus on the patient as a whole throughout life led to specific programs in family practice.

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Field of medicine concerned with the prompt treatment of wounded military personnel. Developments in battlefield medicine have focused on treatment to quickly stop bleeding and on provision of immediate medical care. In the early 21st century these developments, combined with improvements in body armour and helmets, have resulted in the survival of many casualties of war who nonetheless have debilitating injuries such as the loss of a limb. Soldiers who have been wounded are taken from the scene of battle to their unit's closest treatment facility. There a team of surgeons and medical staff stabilize the wounded for transport to a larger facility with more specialized staff and equipment. Wounded military personnel may then be transferred for further treatment; those who cannot be returned to duty receive extended care and rehabilitation. Challenges facing military medicine today include the treatment of post-traumatic stress disorder and other psychological damage resulting from service in a war zone, as well as the development of better prosthetics for soldiers surviving the loss of a limb.

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Northwest section of the Front Range, in the central Rocky Mountains, U.S. Averaging a height of 10,000 ft (3,050 m), the mountains run southeast for about 100 mi (160 km) from Medicine Bow, Wyo., to Cameron Pass, Colo., just northwest of Rocky Mountain National Park. The highest summit, Medicine Bow Peak, reaches 12,014 ft (3,662 m). The name refers to the practices of local Indians, who collected wood for bows in the area and held ceremonial medicine dances.

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