A brief history of Western medicine starts with Galen and takes one from the humoral-imbalance theory to the late 19^th century germ theory of disease. A key turning point in medicine was the Flexner Report of 1910, which facilitated the transformation of medicine into a science-based enterprise in which clinical practice, research, and medical education began to fuse. The leading site of this fusion was the American academic medical center, which began at such leading institutions as Johns Hopkins, Harvard, and the University of Pennsylvania. Duke University joined the trend in 1924 and ever since has been one of the major academic medical centers in the world.