Industries & Professions /
Health Care Providers
The origins of medicine began with prehistoric people who
believed that diseases were derived from supernatural powers. To
destroy the evil spirits, they performed trephining, which involved
cutting a hole in the victim's skull to release the spirit. Skulls
have been found in which the trephine hole has healed,
demonstrating that people did survive the ritual, although it may
be assumed that trephining did little to help the afflicted person.
The first doctors, known as medicine men, also used herbal
concoctions, ritual dances, and incantations to heal their
In about 3000 B.C., the ancient Egyptians
developed a systematic method of treating illnesses, which
introduced the notion of specialization within the field of
medicine. The famous physician Imhotep was so respected that the
Egyptians regarded him as the god of healing.
The Greek physician Hippocrates was the first person to declare
that disease was caused by natural, not supernatural, phenomena. He
introduced a method of conduct and ethics for the practice of
medicine. To this day, each physician pledges the Hippocratic Oath
on their day of graduation from medical school.
Another Greek physician, Galen of Pergamum, studied in Rome
during the second century A.D. He worked as
physician to Emperor Marcus Aurelius and lectured to physicians on
dissections and experimental physiology. He conducted anatomical
studies of animals, particularly apes, because the dissection of
humans was illegal. He is credited with the discoveries of blood
transport by arteries, the pumping mechanism of the heart, and the
function of the kidneys. His written work remained influential for
hundreds of years, and during the 15th and 16th centuries, many
physicians repeated his experiments to gain further insight into
the mechanism of human anatomy.
Avicenna, from Persia, was another major contributor to the
early development of Western medicine. His single largest
contribution was the book The Canon of Medicine, which
included the information of Greek and Arabic physicians that had
been gathered from many generations, as well as some of his own
findings. The book remained the most important publication for
medicine through the 16th century and served as a major resource of
information for Eastern and Western countries.
When dissection of human corpses was accepted in the 1500s,
Andreas Vesalius was able to conduct his own examinations and
correct many of the errors that Galen had made. Vesalius published
On the Structure of the Human Body in 1543, which provided
the basis for future study of human anatomy.
William Harvey made an important contribution to medicine in the
17th century. Using the observations Hieronymus Fabricius had made
on the valves in veins, Harvey conducted physical tests to prove
that blood circulates through the body and through the veins and
arteries. He wrote On the Motion of the Heart and Blood in
Animals in 1628.
It was the development of the microscope that moved medical
study into the next plane of understanding. Zacharias Janssen, a
Dutch eyeglass maker, discovered the benefits of combining
magnifying lenses. He is credited with developing the first
compound-lens microscope around 1590.
Another Dutch scientist, Anton Van Leeuwenhoek, used microscopes
to study the microscopic contents of water, blood, and other body
fluids and tissues. He described bacteria from his observations,
becoming the first person to recognize the presence of foreign
bodies in human fluids.
Discoveries were made more rapidly once the concept of germ
infection became recognized and accepted. The awareness of
bacteria, fungi, and viruses led to concepts, taken for granted
today, that proved to be a major boon to the medical profession.
Washing hands before surgery, examinations, and deliveries of
newborns led to a decrease in cases of infections and death. Joseph
Lister developed the concept of an antiseptic environment that
promoted sterilized equipment and surroundings in medical work.
Louis Pasteur successfully produced vaccinations that battled
diseases. In the mid-1800s, Pasteur inoculated sheep against a
common animal disease called anthrax. He went on to develop a
vaccination against rabies, demonstrating that vaccinations were as
successful in preventing disease in humans as they were in
Another discovery that the modern world relies on every day is
the development of anesthesia. Surgery had been performed without
it for hundreds of years, but it was hazardous and extraordinarily
painful. In 1846, a surgery by William Morton in Boston before a
group of physicians proved to the medical world that the use of
anesthesia freed the patient from surgical pain and allowed the
physician to work more accurately, more thoroughly, and more
extensively than ever before. Early anesthetics included nitrous
oxide, ether, and chloroform.
Drugs were discovered that battled and killed some bacteria and
infections. Penicillin was discovered by Alexander Fleming in 1928.
Howard Florey and Ernst Chain were able to isolate the penicillin
compound in pure enough quantities to use it to combat infections
such as staph. That advance in 1938 led to mass production, which
allowed the British and American armies to use it on wounded
soldiers through World War II. The number of lives saved by
penicillin is beyond calculation.
Immunologists and bacteriologists experimented with methods of
inoculating soldiers against viral infections. Tetanus antitoxin
was developed by Emil von Behring and Shibasaburo Kitasato in 1890.
The two also worked on diphtheria antitoxin, which, only after the
vaccinations had a combination of toxins and antitoxins, would
produce an immune response in humans.
During the 1930s, technology was developed that allowed
immunologists to isolate and cultivate viruses for study and
experimentation. As viruses were isolated, the proper vaccinations
could be developed that would trigger immunization in humans. The
most heralded of the vaccines was the one developed by Jonas Salk
for poliomyelitis (polio). Albert Sabin developed an oral vaccine
soon after, which also immunized against polio. Polio had infected
hundreds of thousands of people in the United States between 1940
and 1959 and had killed 26,635 people, according to the National
Center for Health Statistics. Initial use of the vaccination began
in 1954. In 1960, thanks to the vaccination, only 3,190 Americans
developed the disease.
Viruses still plague the population and therefore impact on the
medical community. Acquired Immunodeficiency Syndrome (AIDS) is the
most deadly virus to affect the population. By 2007, 583,298 people
had died from AIDS in the United States, according to the Centers
for Disease Control (CDC), and the disease had been diagnosed in
468,578 others. Severe acute respiratory syndrome (commonly known
as SARS) is a viral respiratory illness that was first reported in
Asia in 2003. Before the outbreak was contained, SARS spread to
more than 24 countries in North America, South America, Europe, and
Asia. According to the World Health Organization, 8,098 people
worldwide contracted SARS during this outbreak and 774 of that
group died. Researchers are attempting to find a preventive
vaccination and a cure for these deadly viruses.
The health care industry continues to develop at a rapid rate
with the discoveries of new drugs, treatments, and cures. Modern
technologies, such as computers and virtual reality, are being used
by the medical community to perform tests, compile data, diagnose
illnesses, and train professionals. Many surgeries are no longer
performed with a scalpel, but with lasers. Disease, illness, and
injury are now being treated and cured so successfully that the
general population is living much longer and the number of elderly
Scientists are conducting promising research in the field of
genetics. Knowledge about genes could help doctors identify people
who have genetic predispositions to certain diseases and perhaps
lead to a cure for such illnesses as Parkinson's disease and some
types of cancer.
The medical and health care field has become one of the largest
and most varied occupational areas. Approximately 14.3 million
people were employed in some aspect of the U.S. health care system
in 2008, according to the U.S. Department of Labor. Health care
workers are employed as physicians, nurses, nursing aides,
technicians, technologists, therapists, and in a host of other