The history of medicine is both a study of medicine throughout history as well as a multidisciplinary field of study that seeks to explore and understand medical practices, both past and present, throughout human societies.The history of medicine is the study and documentation of the evolution of medical treatments, practices, and knowledge over time. Medical historians often drawn from other humanities fields of study including economics, health sciences, sociology, and politics to better understand the institutions, practices, people, professions, and social systems that have shaped medicine. When a period which predates or lacks written sources regarding medicine, information is instead drawn from archaeological sources. This field tracks the evolution of human societies' approach to health, illness, and injury ranging from prehistory to the modern day, the events that shape these approaches, and their impact on populations. Early medical traditions include those of Babylon, China, Egypt and India. Invention of the microscope was a consequence of improved understanding, during the Renaissance. Prior to the 19th century, humorism (also known as humoralism) was thought to explain the cause of disease but it was gradually replaced by the germ theory of disease, leading to effective treatments and even cures for many infectious diseases. Military doctors advanced the methods of trauma treatment and surgery. Public health measures were developed especially in the 19th century as the rapid growth of cities required systematic sanitary measures. Advanced research centers opened in the early 20th century, often connected with major hospitals. The mid-20th century was characterized by new biological treatments, such as antibiotics. These advancements, along with developments in chemistry, genetics, and radiography led to modern medicine. Medicine was heavily professionalized in the 20th century, and new careers opened to women as nurses (from the 1870s) and as physicians (especially after 1970). Source: Wikipedia (en)