Virchow adds, "Müller himself was what he styled one of his greatest predecessors--perpetually a priest of nature. The religion which he served attached his pupils to him as it were by a sacred bond; and the earnest, priest-like manner of his speech and gestures completed the feeling of veneration with which everyone regarded him."
In the recently issued life of von Helmholtz, the great German physicist, his biographer makes it very clear how much Helmholtz thought of Müller, one of the earliest teachers. [Footnote 10] Helmholtz, Brücke, and Du Bois-Reymond were warm personal friends (college chums we would call them in America), and all fervent admirers of their greatest [{248}] master, who showed them, as Helmholtz says, "how thoughts arise in the brains of independent thinkers." A half-century later, in his recollections of the time, he said: "He who has come in contact with one or more men of the first rank has his mental intellectual standard for all time broadened, and such contact is the most interesting thing that life can hold." Curiously enough, one of the most interesting things in Helmholtz's recollections is that, despite the fact that the poverty of his parents made it advisable for him to get through his medical studies as soon as possible, Müller persuaded him to take another year's medical work before going up for his graduation. This was mainly for the purpose of having his pupil complete an essay in physiology on which he was engaged. Müller offered him the use of his own laboratory and all his instruments for this purpose. His judgment was justified by Helmholtz's wonderful work on the conservation of energy made within a few years after his graduation.
[Footnote 10: Herman von Helmholtz, von Leo Koenigsberger. Bd. 2, Braunschweig, Friedrich Viewig und Sohn, 1902-3]
Müller's death was sudden, though not entirely unexpected. He had been ailing for many months and had resolved to give up his lectureship. He had made most of his preparations for settling up his affairs, and had even sent for his son, who was practising medicine at Cologne, to come up to see him. He made a special engagement for a consultation with his physician for a certain morning, and having gone to bed in reasonably good spirits, in fact, feeling better than he had for a long while, was found dead in the morning. Some time before he had made his will forbidding an autopsy, and so the exact cause of death will never be known, though it is rather easy to surmise that it was due to apoplexy, as arteriosclerosis--that is, degeneration of arteries--had been noticeable in Müller for some years, and his temporal artery particularly had become hard and tortuous.
Müller was buried with all the rites of the Church, and as [{249}] in Germany the ecclesiastical authorities are very strict in this matter, there can be no doubt that the great physiologist had been a faithful Catholic. He was known for his edifying attendance at Mass on all the Sundays of the year. Many years afterward, in the midst of the Kulturkampf in the early seventies, a monument was erected to him in his native Coblentz, and the occasion of its unveiling was taken by the Catholic Rhineland for a celebration in honor of their great scientist.
For a time, in his younger years, Müller appears to have been not all unaffected by the materialistic tendencies so rife in the science of the time. His early anatomical investigations seem to have clouded somewhat his faith in things spiritual. One of the expressions attributed to him before his twenty-fifth year is that nothing exists in the human being which cannot be discovered by the scalpel. It was not long, however, before Müller repudiated this expression and came back to a realization of the importance of the immaterial. Another expression attributed to him, "Nemo psychologus, nisi physiologus," "No one can be a psychologist, unless he is a physiologist," has been often repeated as if Müller meant it in an entirely materialist sense. As a matter of fact, however, it is intended to convey only the idea that no one can really exhaust the science of psychology unless he knows the physiology of the brain, the organ which the mind uses in its functions in this life. The expression is really the foundation of the modern physiological psychology, which is by no means necessarily materialistic in its tendency, and has become a favorite subject of study even with those who appreciate thoroughly the importance of the immaterial side of psychology.
Müller seems never to have gotten so far away from the Church as that other great physiologist of the succeeding generation in France, Claude Bernard, who for many years allowed himself to be swamped by the wave of materialism [{250}] so likely to seem irresistible to a scientist engaged in physiological researches. But, even Claude Bernard came back to the Church before the end, and, under the guidance of the great Dominican, Père Didon, reached the realization that the only peace in the midst of the mysterious problem of life and the question of a hereafter is to be found in a submissive faith of the doctrines of Christianity.
Many years ago, when Virchow took it upon himself to say harsh words in public of Catholic scholarship, and to put forward the hampering influence of the Church on intellectual development as a reason for not allowing Catholics to have any weight in educational matters, the organ of the Catholics of Germany, Germania, reminded him that his own teacher, the great Johann Müller, the acknowledged father of modern German medicine, and the founder of the fecund scientific method to which so many discoveries in the biological and medical sciences are due, had been brought up and educated a Catholic, had lived all the years of his productive scholarship and fruitful investigation in her bosom, and had died as an acknowledged son of the great mother Church.
Müller is certainly one of the great names of nineteenth century science. When many another that seems now as well, or perhaps even better known, shall have been lost, his will endure, for his original researches represent the primal step in the great movement that has made possible the advances in nineteenth century medicine. He was honored by his contemporaries, venerated by the men of science who succeeded him; he has been enshrined in a niche for himself by posterity, and his name will remain as that of one of the great geniuses to whose inventive faculty the world owes some of those steps across the borderland into the hitherto unknown which seem so obvious once made, yet require a master mind to make and mean so much for human progress.