THE TWENTIETH CENTURY
Medicine in the 20th century made enormous advances in the basic medical sciences. It also expanded
to take full advantage of the equally rapid strides being made in all the other fields of science and technology. As a result, no synopsis of the achievements of
medicine in the century can really be provided here. Individual entries on the various fields of medicine provide such current reviews.
Antibiotics
One major area of advance in 20th-century medicine has been in pharmaceuticals, and in particular the development of antibiotics. Pioneering in this field, German bacteriologist Paul Ehrlich began his career by discovering that many cells would bind to specific dyes then being developed by the German chemical industry. In this way he discovered certain of the body's white blood cells and was able to stain the tubercle bacillus, a crucial step in identifying the tuberculosis-causing organism and developing means of controlling the disease. In 1909, Ehrlich synthesized arsphenamine, a drug that could destroy the syphilis-causing organism Treponema pallidum. With this accomplishment, Ehrlich ushered in the age of antibiotics and chemotherapy. His concept that molecules would adhere to one another if their shapes were complementary also became one of the basic concepts of immunology as well as of general body chemistry.
The German physician Gerhard Domagk, working 25 years after Ehrlich, developed the first useful sulfa drug, or sulfonamide, which was used to treat streptococcal disease. In 1929 the British bacteriologist Alexander Fleming discovered penicillin, which destroys various bacteria. During the stress of World War II the drug was purified, manufactured on a huge scale, and shown to be safe and effective in treating a host of diseases, including gonorrhea, syphilis, and meningitis. In 1943 the microbiologist Selman Waksman discovered streptomycin, the first antibiotic effective against tuberculosis; it was also effective against a number of other bacteria not affected by penicillin. Many antibiotics are now in use, one or the other of them efficacious against most of the bacterial infections found in patients with a normal immune system.
Vaccines
The 20th century has seen the conquest of a number of diseases through immunization. Smallpox, as noted, has disappeared worldwide. In technologically advanced countries a number of childhood diseases such as poliomyelitis, rubeola (measles), rubella ( German measles), diphtheria, and mumps now occur infrequently and sporadically. Vaccines against diseases such as influenza have also been developed, but influenza and a number of others remain difficult to control because of the many varieties of the virus and its capacity to mutate. Such difficulties surround current
research on a vaccine against the deadly acquired immune deficiency syndrome. Research medicine is thus heavily involved in efforts to understand the immune system, not only with respect to AIDS but also because of other diseases such as rheumatic fever, rheumatoid arthritis, and lupus erythematosus. Also, because many cancer cells have been shown to be capable of combining with unique antibodies, the possibility exists that at least some cancers may ultimately be dealt with through immune-related methods such as vaccines.
Medical Genetics
Medical research at the cellular level, such as on the immune system, has been made possible through 20th-century advances in genetic techniques. The causes of many diseases have been traced to defective chromosomes or to specific genes on the chromosomes. The hope is that such diseases can eventually be treated through direct intervention, using the techniques of genetic engineering. By means of such techniques, several natural body chemicals have become available in quantity, including insulin, interferon, clot-dissolving enzymes, and human growth hormone. Medical researchers have begun mapping of the entire human genome.
Medical Technoogy
The contributions of other fields of science and technology to advances in 20th-century medicine and surgery have been so numerous that only one such field can be chosen as an example. That is, the discovery of X rays led rapidly to their employment in various diagnostic and therapeutic ways, and their use in medical research made possible the elucidation of the structure of molecules such as DNA, proteins, and vitamins. Basic medical science has also become significantly dependent on the use of radioactive isotopes, by means of which various biosynthetic processes and the degradation of biochemicals within the body can be elucidated. Such isotopes have also made possible the detection and quantification of molecules that are present in body tissues in such minute concentrations that they could not otherwise be measured. Modern diagnostic tools now include a wide range of advanced devices.