source : https://library.harvard.edu/
Pierre Charles Alexandre Louis was one of an influential group of early 19th–century physician–researchers known as the Paris Clinical School. Louis was a strong proponent of numerical methods in medicine, and his work comparing different treatment protocols for different groups of patients laid the foundations for the modern clinical trial. He found, for instance, that bloodletting in pneumonia had no effect on outcome. His work is often associated today with the concept of “evidence–based medicine,” which uses the scientific method to evaluate evidence to measure the effectiveness of treatment.
The Paris Clinical School
The Paris Clinical School is sometimes referred to as the first scientific medicine in the 19th century, one that helped pave the way to the idea of specific diseases associated with the germ theory. It is also known as the beginning of impersonal, “objective,” and institutionalized modern medicine, in which patients are evaluated in terms of their deviation from statistical norms rather than from what is normal for each patient as an individual.
Associated with the social and ideological reforms of the French Revolution (1789), the Paris Clinical School rejected the authority of humoral theory, scholastic training based on the study of texts rather than human bodies, and elite private practice. Instead, the Paris School focused on hands–on experience with large numbers of clinical cases, typically found at the large charitable hospitals, such the Hotel–Dieu in Paris.
The Paris Clinical School is also significant for its attention to autopsy as a means for corroborating internal lesions with bedside diagnoses, and for its use of statistics, or, to use the term most associated with Louis, “the numerical method,” to understand the typical course of a disease. The Paris School emphasized accuracy of observation, diagnosis, and detailed understanding of the typical course of common diseases such as tuberculosis.
Notably, the Paris School was not known for its cures and is often associated with a widespread, 19th–century concept known as “therapeutic nihilism.” This concept, held by the public and physicians alike, held that medicine as then practiced made little or no difference in a patient’s outcome.
Americans in Paris
In the first decades of the 19th century, Americans who wanted a truly elite medical education went to Europe, particularly to Paris, to study. In this way, P. C. A. Louis exerted a significant influence on American medicine.
Among these Americans was James Jackson. Jr., whose account of the 1832 Paris cholera epidemic can be found in letters exchanged with his father, the influential American physician James Jackson, Sr. By the 1830s and 1840s, medical innovation was becoming associated with German medical schools and laboratories rather than large public Paris clinics, and Jackson also expresses his desire to spend the next phase of his training there.