Germany has come to occupy so large a place in progressive medicine during the last half-century that it is rather hard to conceive of a time when the Teutonic race was not the head and front of modern medical progress. The leadership that had existed in Italy for over five centuries only passed to Germany at the beginning of the nineteenth century. The first great leader in German medical thought was Johann Müller, and to the wonderful group of students that gathered around him German medicine owes the initiative which gradually forced it into the prominent place it still holds in the world of medicine. The great institutions of learning that have since come in Germany did not exist with anything like their modern systematic arrangement when Müller began his work. It was the marvellous influence of the man as a teacher, and not the scientific aids afforded by institutional methods, that brought forth the great generation of teachers which followed immediately on Müller's footsteps. Nowhere more than in the life of Müller can it be recognized with absolute certainty that the system and the institution count for little in education, as compared to the man and his methods. The keynote of Müller's career, even more than what he did for biology, and for all the biological sciences related to medicine, is the wonderful conservatism of thought which characterizes his scientific conclusions, while at the same time he began the application of the experimental methods {218} to medicine as they had never been applied before. At a time when physiologists, because of Woehler's recent discoveries of the possibility of the artificial manufacture of urea, might easily have been led to the thought that life counted for little in the scheme of the universe, Müller continued to teach consistently that vital energy may direct chemical or physical forces, but must not be confounded with them. It looked as if in the development of the chemistry of the carbon compounds, all of which are the result of life action, that materialistic views must be expected to prevail. Müller insisted, however, that life ever remains the guiding principle which rules and coordinates all the physical and chemical forces at play, within living organisms; and that the vital principle is entirely independent of these forces so closely attached to matter.