The old classical training, supposed to be so useless in this matter-of-fact, practical age, trained the minds of the men who have given us all the great discoveries in science. The evolution of intellectual power consequent upon the serious study of many things proved an aid rather than a hindrance to future original work. Not one of these great scientific investigators had at the beginning any hint of the work that he was to do. It seems almost an accident that their researches should have been conducted along certain lines which led to important discoveries. What was needed for them was not special training, but that mental development which puts them on a plane of high thinking above the already known, to look for progress in science. Müller continued for many years to entertain the idea of eventually becoming a priest. At about the age of sixteen, however, he became deeply interested in Goethe's work, and was especially attracted by the great poet's studies of scientific subjects. About this time he became interested in the collection of plants and animals and took up seriously the study of physiology. Lavater's work was, at that time, still sufficiently recent to have little of the novelty worn off, for young students, at least. At the age of eighteen Müller went to Bonn and, when about to begin his university career, hesitated as to whether he should study theology or not. His natural liking for nature study, however, finally caused him to decide in favor of a scientific career, and he began the study of medicine. {228} He took up his medical studies with the greatest enthusiasm. Under the special guidance of Mayer, who besides being his teacher was a personal friend, he applied himself zealously to the study of anatomy. One of his expressions in his early student days that has often been repeated, but which Müller took the greatest care in later life to correct and deny as a lasting impression, was the famous "Whatever cannot be demonstrated by the scalpel, does not exist." The professor of physiology at the time at Bonn was the famous Fredrich Nasse, especially known for the wonderful attractiveness of his lessons and his power of arousing enthusiasm in others, and it is not surprising that Müller, naturally so enthusiastic in scientific studies, should have acquired a liking for the study that he never afterward lost.