At the beginning of the 19th century, American physicians contributed very little to medical science and were thought to be inferior medically when compared to European counterparts. European countries' medical practices heavily relied on and included medical science and research, as the United States still continued to believe that each individual partook in a disease differently. As the United States progressed into the 19th century, their thoughts on medicine, science and practice needed to adjust along with other countries to institute a standing as a medical power in the world. As to compete with the Europeans, American medicine transformed through the expansions of theories, new technology, the usage of a European model, the opening of Johns Hopkins University, and Alex Flexner's standards. .
In the beginning and midway through the 19th century, typical practices of medicine were not at all based on scientific thought or evidence. Many practitioners believed in the idea of humoralism, which was the thought that health resulted from a natural balance of the bodily humors: yellow bile, blood, phlegm, and black bile. Doctors also believed that a disease took a different entity within each individual based on their environment, the season that they were in and their ethnicity; also known as specificity.11 With the introduction of medical science to the medical practice, the theory of universalism came into play more than specificity. Universalism was the thought that there should be a uniformity in disease. Also, each person had a normal state of balance that was uniform among all patients by the use of collected data and the creation of a bell curve, indicating deviants. This allowed doctors to generalize diseases and diagnostics among a population rather than treating someone on an individual basis and background. Another theory that came largely into play was the Germ Theory.