19th
Century
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
palaeontologist James Parkinson described the chronic nervous system disease
called Parkinson disease; and the Irish physician Robert James Graves diagnosed
the thyroid disorder exophthalmic goitre, 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 (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 behaviourism. 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 (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 (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 anaesthesia. 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 anaesthetic effects of
ether in 1842, and the dentist William Morton used ether in a tooth extraction
in 1846. Ether and other anaesthetics 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.