JOHANN MÜLLER, FATHER OF GERMAN MEDICINE
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.
All Müller's disciples, and they were the representative biological scientists in Germany during the nineteenth century, followed closely in his footsteps in this matter, and the result was a conservatism of thought in biology in Germany that is the more surprising when we realize how much German philosophers in their systems emphasized the necessity for absolute independence from all previous systems of philosophical speculation. It is so much more interesting, then, to find what was the method of education that made of Johann Müller so conservative a thinker, while not injuring his genius for experimental observations. The influences that were at work in his earlier years were evidently those that made him subsequently the bulwark against materialistic tendencies in biology, and yet did not impair his originality. His early education was obtained under influences that are usually considered to be distinctly harmful to independence of thought, and yet they seemed to have helped him to the fulfilment of his destiny, as a great thinker and investigator. [{219}] Müller is undoubtedly one of the very great men of modern science, and is the recognized founder of the system and methods of investigation which have given German medicine its present prominence and prestige.
In recent years there have been many tributes to Müller, because as Virchow's teacher it was considered that some of the praise for the work done by Virchow must naturally reflect on the man to whom the great German pathologist acknowledged that he owed so much of his inspiration and his training in methods of investigation. Virchow's death too very naturally led to the recall of what had been accomplished in German medicine during the nineteenth century, and for much of this Johann Müller must be considered as at least indirectly responsible, since to him so many of the great German medical scientists owed their early training. These men, all of them, did not hesitate to attribute the progress of German medicine to the methods introduced by Müller. At the beginning of the twentieth century something of the estimation in which he was held in a land far distant from the German Fatherland may be gathered from the following tribute paid to him in a recent meeting of the Medical Society of the State of New York by Dr. C. A. L. Read, of Cincinnati, former President of the American Medical Association. In the midst of his panegyric of Virchow Dr. Read described in some detail the medical faculty of Berlin at the time when Virchow was beginning his work as a student at that University. He said:
"In the faculty there were Dieffenbach, the foremost surgeon of his day; Schoenlein, the great physician who had come from Zurich the same year to join, not only the teaching body, but to act as a reporting counsellor for the ministry and to serve as physician-in-ordinary to the King; Froriep, who was in charge of the Pathological Institute; Caspar, who [{220}] was also medical counsellor, with a seat in the special deputation for medical affairs in the ministry; but towering above them all was the intellectual figure of Johann Müller, the Professor of Physiology. He was an original genius with daring, actually engaged in winnowing the wheat of demonstrated truth from the prevailing chaff of egoistic opinion which divorced physical science from speculative philosophy. Prompted by the inspiration which he had derived in turn from Bichat and the French school, the Professor of Physiology was busily retesting in the laboratory truths previously elaborated by Haller, Whytt, Spalanzani, Cullen, Prochaska, John Hunter, the Bells, Magendie, Berzelius and Bichat himself."
This is the tribute to Johann Müller, nearly fifty years after his death. That of Virchow, at his obsequies in Berlin, is even more enthusiastic. Virchow, then at the age of thirty-seven, at the height of his powers, already acknowledged the greatest of living pathologists, just recalled to Berlin to become Professor of Pathology in the University which he had left more or less in disgrace because of his political opinions, could not say too much of the teacher whom he respected and honored so highly and whose inspiration he felt stood for so much in his own career.
He said:
"My feeble powers have been invoked to honor this great man whom we all, representatives of the great medical family, teachers and taught, practitioners and investigators, mutually lament and whose memory is still so vividly with us. Neither cares by day nor labors by night can efface from our mind the sorrow which we feel for his loss. If the will made the deed, how gladly would I attempt the hopeless task of proper appreciation. Few have been privileged, like myself, to have this great master beside them in every stage of development. It was his hand which guided [{221}] my first steps as a medical student. His words proclaimed my doctorate and from that spot, whence now his cold image looks down upon us, his kindly eyes beamed warmly upon me, as I delivered my first public lecture as Privat-Docent under his deanship. And, in after years, I was the one out of the large number of his pupils who, by his own choice, was selected to sit beside him within the narrow circle of the faculty.
"But how can one tongue adequately praise a man who presided over the whole domain of the science of natural life; or how can one tongue depict the master mind, which extended the limits of his great kingdom until it became too large for his own undivided government? Is it possible in a few short minutes to sketch the history of a conqueror who, in restless campaigns, through more than one generation, only made use of each new victory as a standpoint whereon he might set his feet and boldly look out for fresh triumphs?
"Yet such is the task to which we are called. We have to inquire what it was that raised Müller to so high a place in the estimation of his contemporaries; by what magic it was that envy became dumb before him, and by what mysterious means he contrived to enchain to himself the hearts of beginners and to keep them captive through many long years? Some have said--and not without reason--that there was something supernatural about Müller, that his whole appearance bore the stamp of the uncommon. That this commanding influence did not wholly depend on his extraordinary original endowments is certain, from what we know of the history of his mental greatness."
Virchow's tribute could not well be more enthusiastic or more ample. His appreciation has been the standard for all other medical opinions of the man. How much Müller is honored at the present time in Germany can be best [{222}] appreciated from the number of times that his name is mentioned with respect and often with laudation in the proceedings of German medical societies. Scarcely a meeting passes in which more than once Johann Müller is not referred to as the founder of the scientific method in medicine which has given Germany her present position in the very forefront of medical scientific progress. It is a common expression, said half in jest it is true, but surely more than half in earnest, that the proceedings of no medical society would be really successful within the bounds of the German fatherland unless they were hallowed by an invocation of the great name of Johann Müller, the revered patron of modern German medicine. This is no witticism by exaggeration, after the American fashion, but a sincere Teutonic expression of feeling that occupies German medical minds with regard to the man who founded the most progressive school of modern medicine, and in doing so brought honor to his native country.
Johann Müller was born at Coblentz, on July 14, 1801. About six months before, the Emperor of Austria by the treaty of Luneville, signed February 9, 1801, ceded to the French Republic all the Austrian possessions on the left bank of the Rhine. The electors of Treves, who were archbishops and reigning princes and who had resided for centuries at Coblentz, by this treaty disappeared forever from the list of German rulers. When Johann Müller was born, French prefects of the Departments of the Rhine and Moselle took up their residence in the old town which had been, since the beginning of the French Revolution, a favorite dwelling place for the French nobility driven from their homes by fear of persecution.
Müller's father was a shoemaker and lived in a small house in the street of the Jesuits, so called because the fathers had had a school in it for many years. Johann was [{223}] not destined to receive his education from the Jesuits, however, for the order had been suppressed nearly thirty years before his birth, and did not re-establish itself in the Rhineland for many years afterward. The circumstances of the Müller family were not such as to encourage hopes of a broad education, though his father seems to have taken every possible means to secure as much school training as could be obtained for his son. The early death of his father promised to deprive Müller of whatever advantages might have accrued from family sacrifices, but his mother was one of these wonderful women who somehow succeed in raising their families well and affording their children an education in spite of untoward circumstances.
Johann was the eldest of five children, with two sisters. He was very proud himself of the fact, that while he took from his father a large, strong, healthy frame and a dignified carriage, he had his mother's skill for putting things in order, her constancy of enterprise and her tireless faculty for hard work. After his father's death, his mother's energy and good sense enabled her to carry on the business established by the elder Müller by means of assistants, and as Coblentz was the centre of a district that during the Napoleonic wars was constantly overrun with soldiery, the shoemaking trade was profitable.
Johann seems to have learned the trade, but his mother succeeded in enabling him to begin his education seriously at the age of eleven or twelve. About this time, Joseph Görres, who was afterward the great leader of Catholic thought in Germany, and after whom is named the famous Görres Gesellschaft which stands for so much in German Catholic life and progress, was a professor in the Sekunden Schule, or secondary school, in Coblentz, and had recently published treatises on natural philosophy with special [{224}] reference to physiology. Müller entered this school in 1810 and Görres did not resign his professorship until 1814, when owing to the publication of a political work he was obliged to flee from the country. It is not known how much influence Görres exercised over young Müller, but some at least of his precious love for the natural sciences, which even in his student days led to the making of natural collections of various kinds, seems to have been imbibed under the influence of the philosopher physiologist. The touching of the orbits of the two men, who were destined, more than any of their fellow-citizens of Coblentz, to influence Germany's future, must always remain an interesting consideration in the lives of both.
Johann's parents were, as might have been expected, down in the old Catholic Rhineland in the capital of the spiritual principality of Treves, faithful members of the Roman Catholic Church. Very early in life, Johann conceived the wish to become a priest. His mother, rejoiced at her son's idea, was ready to make every possible sacrifice to secure his education. It was with the intention of education for the priesthood, then, that Johann entered the Sekunden Schule, an old college of the Jesuits, in which Jesuit tradition and methods of education still survived, and in which some of the old Jesuit pupils seem still to have held positions even during Müller's time as a student (1810 to 1817).
It would appear probable that because of the traditions of Jesuit teachings that held over at the school in Coblentz, and perhaps, too, because of the presence of some of the old masters and teachers trained by them, Müller knew the ancient languages so well. He made his own translations of Plato and Aristotle, and consulted the latter especially always in the original and had a lifelong reverence for the great Greek philosophic naturalist's work, Latin he used [{225}] so well as to speak it readily, and practice in the disputations of the University at Bonn made the language still more familiar to him. It was said that he wrote Latin better than German. After the fall of Napoleon the Prussian government took up the reorganization of the schools in this part of the Rhineland, and Müller became more interested in scientific studies. At this time he became devoted to mathematics, which he studied under the old pupil of Pestalozzi, Professor Leutzinger, to whom Müller, in the sketch of his life prefixed to his thesis at the university, expressed the feeling that he owed a special debt of gratitude.
During his school days Müller became a collector, as we have said, of natural objects. He was especially interested in butterflies for a time, and collected all the species in the country around. He had a curious dislike for spiders which remained with him all his life. He was able to overcome this, however, and made important studies of that insect's eyes, and of its changing expressions under the influence of fear or when about to fall upon its prey.
His feeling with regard to the insect is an index of a certain feminine quality of mind that had a characteristic expression in later life in his dislike for vivisection. He could not bring himself to the conclusion that animals must be sacrificed in the midst of horrible pain unless there was some very definite scientific point to be determined, and unless every precaution was taken to avoid inflicting needless suffering. Even then he preferred that others should do this work and more than once took occasion to point out the fallacy of physiological observations founded on animal experimentation under such anomalous circumstances, and insisted that very frequently the results gave conclusions only by analogy and not by any strict logic of animal similarity or absolute physiological nexus.
In a sketch of Müller's life, by Professor Brücke, of Vienna, himself one of the most distinguished physiologists of the nineteenth century, to whom the University of Vienna has paid the tribute of a marble bust and tablet in its courtyard, the great Austrian physiologist sums up very well the reasons for Müller's fame. Professor Brücke's tribute may be found in the Medical Times and Gazette, of London, July 17, 1858. "If we inquire," he says, "what were the circumstances to which Müller, independently of his high intellectual endowment, his gigantic power for work, the energy and massiveness of his character, and his active and vigorous bodily constitution, owed the commanding position he incontestably held among men of science in our day, we must admit that before all things this was due to the breadth and depth of the foundations upon which his intellectual cultivation had been built." Professor Brücke then dilates on the variety of scientific interests which occupied Müller's earlier years and the thoroughness with which he accomplished everything that he set himself to.
A very curious reflection on our modern methods of education, and especially the tendency to specialization and the formation of specialists from their very early years, is to be found in Brücke's account of the extent and variety of Müller's studies in all lines. Far from considering that these diverse intellectual interests hindered the development of his genius, he seems to consider that they rather aided in the evolution of that largeness of mind characteristic of the great genius. He says:
"In his schooldays Müller's attention was directed to subjects of study far beyond the mere medical curriculum, for we find him attending the lectures of celebrated professors on poetry and rhetoric, on the German language and literature, on Shakespeare and Dante." As a matter of [{227}] fact, Brücke seems to have understood that no one is so little likely to make scientific discoveries as he whose mind has been directed without diversion along the narrow lines of a specialty in science. Constantly trained to see only what lies in the sphere of this short-sighted interest, the mind never raises itself to a view beyond the horizon of the already known.
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.
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.
During Müller's second year of medical study the University of Bonn announced its first prize, which was to be given for an investigation of the subject of respiration in the foetus. Although Müller was only in his first year as a medical student at the time, he grappled with the difficult subject and devoted all his spare time to arranging experiments for the demonstration and investigation of doubtful points. He received the prize, and Virchow, surely a good judge in the matter, says that this work of his student days is distinguished alike by the extent of its learning and by the number and boldness of the experiments detailed. At the moment of his graduation, the young doctor, in his twenty-first year, was already a marked man. From this time on everything that he did attracted attention and had a ready audience.
Müller's mind was constantly occupied after this time with the arranging of experiments to demonstrate natural principles. How far he carried this habit of experimenting can be understood from some of the habits of control over [{229}] his muscles which he had acquired by continual practice and intense attention. He had thorough control over the muscles of his ears and used often to amuse his fellow-students by their movements. The anterior and posterior muscular portions of this occipito-frontalis muscle were able readily to move his scalp and produce curious disturbances in his hair. These habits of muscular control many people have acquired. Other acquisitions of Müller's are, however, much rarer. He could, at will, contract or dilate his pupils, having secured control over his iris by practice before a mirror, and he could use the little muscles that connect the bones within the ear, the hammer, anvil and stirrup, so as to make them produce an audible click at will.
His habits of experimentation on one occasion at least placed him in a rather ridiculous position. While making his military service, it happened one day that when the command "Order arms" was given, Müller amused himself by inserting one finger after another into the muzzle of his firelock. At last his middle finger got fairly wedged into the weapon. When the order attention was given, Müller could not withdraw his finger. His predicament at once attracted notice, and he was ordered to the front to be reprimanded by the major, to the no small amusement of his comrades, who laughed heartily at his ridiculous predicament. He was sent to his quarters in disgrace and the regimental surgeon had no little trouble in liberating the thickly swollen finger.
While everything thus seemed to promise a life of experimentation, Müller's imagination had a powerful hold on him, and he gave himself up for some time to certain mystical theoretical questions and problems of introspection which, for a time, threatened to take him away from his real calling of an experimental physiologist. Fortunately for Müller, as we shall see, though at the moment he doubtless [{230}] thought it a serious misfortune, these excursions into a too introspective psychology were followed by nervous troubles, what we could now call neurasthenia, and he was consequently led back to the study of external nature.
Just after Müller's promotion to the doctorate in medicine, the Rhenish universities came once more under the authority of the Prussian government, and Berlin became a Mecca for students, who looked upon it in a way as the mother university. After his graduation at Bonn, then, Müller was attracted to Berlin, and came especially under the influence of Rudolphi, who recognized his talents and gave him special opportunities for original investigation. Rudolphi's private library and his collection were placed at the command of this young original worker, who had already proved his power of investigation and his capacity for following a subject to its ultimate conclusions, even though those were not yet extrinsically known. While at Berlin, too, Müller came under the influence of the younger Meckel, whom he learned to respect very much. After Meckel's death the Archives of Physiology, previously edited by Meckel, fell into Müller's hands, who successfully continued it for many years.
At Müller's departure from Berlin he was presented by Rudolphi with an English microscope, as a testimonial of the old professor's appreciation of the young man's labors while under his observation. As Müller's pecuniary resources were very limited, this must have been an especially acceptable gift, since it enabled him to continue his researches in embryology, and it was not long before these began to bear fruit. At Bonn, to which Müller returned, he set up as a Privat-Docent in the University, and for several years eked out by teaching the allowance his mother could give him, and even by the practice of medicine.
Bonn, at this time, had a population of perhaps 30,000, [{231}] and had some eighteen regular practitioners of medicine. It is easy to understand, then, that Müller's practice did not add materially to his pecuniary resources. It was not long before he gave up the practice of medicine entirely, led to the step by the sad death of a friend, who, while under his care, suffered from perforation of the intestines, followed by peritonitis. Notwithstanding the rather precarious state of his finances, at the age of twenty-six, Müller married Anna Zeiler, the daughter of a landholder in the Rhineland, not far from Bonn. He had previously dedicated to her a poem, in which he promised her, in lieu of more material advantages as a marriage settlement, an immortal name. The young man seems to have felt something of the genius that was in him, but, then, so have others, and their presages have not always been confirmed by the issue. Shortly before and after his marriage, he applied himself so hard to his investigations of many kinds that within a few months he broke down. The government allowed him a furlough, and for several months he wandered with his bride along the Rhine, in what has been described by a biographer as a "one-horse shay," and came back to his work renewed in mind and body.
As a matter of fact, Müller's breakdown was what would be called at the present time a neurasthenic attack, induced by overwork and too great introspection. He had been experimenting upon himself in many apparently harmless ways, but by methods which often cause serious trouble. It was not an unusual thing for him to fast, in order to note the physiological effect on his mind and senses of the absence of proper nutrition. He would often lie awake for hours at night in the darkness, experimenting upon himself and noting the phenomena induced, especially in his sight, by the total absence of light. He devoted himself, too, to the investigation of the curiosities of second sight; those interesting [{232}] reminders of things seen long ago, though without producing much impression, and which recur at unexpected moments, to make us think that we are seeing again when we are really only unconsciously remembering. He used to exercise a good deal the faculty of bringing up objects into his vision with all the physical peculiarities of actual sight. In this his master was Goethe, who had written extensively on this subject in treating of the phenomena of vision, and who was able himself to recall to his imagination with great vividness the many shades of colors of objects with the sensory satisfaction of actual vision. Müller had this imaginative power only for the reds.
It is not surprising that a young man, engaged too exclusively at this sort of investigation, should have impaired his nervous equilibrium to some degree, and made symptoms, otherwise unimportant, appear to him as the index of serious illness. For a time Müller despaired of ever being himself again. When he had regained his health, however, he realized what had been the essential cause of his nervous condition; and so he never went back to his introspective observations, considering their results somewhat in the nature of a series of illusions.
After this, Müller devoted himself for ten years strictly to his physiological investigations. The best knowledge of what Müller accomplished for scientific medicine, during these early years, can be obtained from Virchow's summation of the discoveries of this period made shortly after his great teacher's death.
Virchow says:
"It was Müller who introduced to the knowledge of physiologists and physicians the doctrine of reflex actions, which had been already indicated by Prochaska, and simultaneously discovered by Marshall Hall and himself. Just before this Müller succeeded in showing an [{233}] easy mode of performing experiments on the anterior and posterior roots of the spinal nerve in corroboration of Bell's teaching of their diverse functions. Thus he had the privilege of establishing for all time two of the greatest practical discoveries of the physiology of the nervous system.
"Next to the nerves the blood became the subject of his researches and he not only naturalized in German medicine the accurate knowledge of the fibrin and blood-corpuscles, which Hewson had cultivated with such fertility in English literature, but he also managed by simple experiment to demonstrate the peculiar composition of the vital fluid. The discernment of right methods of investigation lay ever open to his clear and cultivated intellect, and he knew well that there were cases in which the scalpel and experiments could not determine a question, and where the truth was only to be elicited by means of chemical agents and physical instruments. It was thus he discovered the peculiar gelatinous substance found in cartilage, called chondrin; thus he proved the existence of lymphatic hearts in the amphibia, and thus that he determined not only the organs but all the laws which are concerned in the production of the human voice.
"The special researches of the Bonn epoch are those of the minute structure and anatomy of the glands. They put an end to the controversy which had existed so long between adherents of Malpighi and Ruysch, concerning the sacculated extremities of the glandular follicles, and obtained for us a correct knowledge of these important organs throughout the whole animal kingdom. Perhaps his most important work is that of the Ducts of Müller, the structures (named after him) which form so important a part of the genito-urinary system in the embryo."
Practically all this had been accomplished before he was [{234}] quite thirty-two years of age. In the autumn of 1832, Rudolphi, the professor of physiology at Berlin, died. As Virchow says, candidates sprung up on every side, and some who were the least qualified considered themselves best fitted for the position. Müller took an unusual step which illustrated his decision in character, though in any other it would have seemed an evidence of conceit. He declared, in an open letter, laid before the Minister of Prussia, that his claims were superior to those of any other living physiologist, except John Frederick Meckel. So powerful was the impression produced upon the minister by this letter that he immediately appointed Müller to the vacant chair.
Not long after his appointment to the chair of physiology at the University of Berlin Müller completed the well-known "Hand-book of Physiology," which established his reputation. The book is sometimes spoken of as an experimental physiology, but this is not correct. Müller was no more a mere experimentalist than Haller, and he, himself, heartily detested the tendency which experimental physiology had assumed in France, especially under the influence of Magendie. Part of Müller's aversion to experimental physiology was aesthetic. He could not bear the idea of inflicting so much pain as many of his colleagues inflicted without a thought. In his panegyric of Rudolphi, Müller says: "Rudolphi looked upon physiological experiments as having no relation to anatomical accuracy, and it is no wonder that this admirable man, who had at every opportunity expressed his abhorrence of vivisection, took up a hostile position against all hypotheses and conclusions insufficiently established upon physiological experiments." Müller adds: "We could not have failed to share his righteous indignation, had we seen how many physiologists were using every effort to reduce physiology to an experimental science by the live dissection and agonies [{235}] of innumerable animals, undertaken without any definite plan, and yielding often only insignificant and imperfect results."
Müller shared these views of Rudolphi with regard to vivisection. The uncertainty of the conclusions, the amount of suffering inflicted, and the indefiniteness of the conditions of experiment, so that the conclusions could not have any very great weight, or any special accuracy of information, made him consider such experiments, unless very carefully conducted by trained investigators, as largely a waste of time and infliction of unnecessary pain and a leading astray of physiological advance because of the uncertainty involved.
The qualities in Müller's "Hand-book of Physiology," which gave it its greatest value, are the thorough review of all of the physiological literature of the world which it contains, and the greatest number of original observations it details as the basis of the principles enunciated. Müller himself said, in the preface to his "Hand-book": "I need scarcely remark that it is the duty of a scholar to make himself acquainted with the progress of science among all nations; and this is now possible and, moreover, quite indispensable in these days of progress. A purely German, French, or English school of medical science is barbarism; and in Germany we would consider the idea of an isolated English or French system of natural history, physiology or medicine just as barbarous as the notion of Prussian, Bavarian, or Austrian medicine or physiology."
How valuable the book was as the corner-stone of modern German medicine, may best be judged from Virchow's opinion of it. He says in his panegyric of Müller:
"There are two qualities in his 'Hand-book of Physiology' which have particularly enhanced my estimation of its value--its strictly philosophical method and its completeness [{236}] in facts. Since the time of Haller no one has so thoroughly mastered the entire literature of natural history or collected in all directions so many original experiences, and no one has been at the same time familiar with medical practice, as well as with the remotest provinces of zoology. It has been well said that while Haller often, in doubtful questions, espoused a side which must eventually be forced to succumb, Müller always had the luck (if we may call that luck which was preceded by so much intelligent activity), sooner or later, to discern the opinion that was sure, eventually, of the victory. He was wonderfully fitted for the office of critic by his comprehensive knowledge. He knew how to discriminate the healthy from the unsound, the essential or real from the adventitious or accidental. And, in surveying the whole series of forms--often widely different--among which a well-determined plan of nature seemed to be realized, he knew the changes which not infrequently altered considerably the arrangement and composition of the substances within these forms. In Müller, as a physiologist, it is not the genius of the discoverer, nor the ground-breaking nature of his observations we admire, but rather the methodical exactness of investigation in calculating judgment, the confident tranquility and the perfect consummation of his knowledge."
In a word, Müller owed the success of his career to the perfect poise of his intellect and the admirable critical faculty that guided him in the thorny path of knowledge at a time when there were so few landmarks of real scientific significance to show the investigator what the probable course and progress of real science must be. It was for this reason that, as Virchow has said, the reform of newer views became embodied in him, and in spite of the almost monastical retirement of the scholar, the influence of the method introduced by Müller was not limited to physiology, but continues to [{237}] spread beyond that science in ever-widening circles into the domain of all the biological sciences.
Virchow concludes: "Müller vanquished mysticism and phantasms in the organic kingdom and he was most distinctly opposed to every dangerous tendency, whether it was pursued under the pretext of physiology or belief, or merely in accordance with conjectures. Müller did not discover, but he firmly established the exact method of investigating natural sciences: Hence, he did not found a school in the sense of dogmas--for he taught none, but only in the sense of methods. The school of natural science which Müller created knew no community of doctrine, but only of facts and still more of methods."
He did not confine himself in his studies, however, to the physiology and pathology, nor even to the anatomy and embryology of man. After 1840 he devoted himself to the study of invertebrates and investigated the starfish and the pentacrinites. While engaged in his work on the invertebrates he found that the fossil remains of animals had not been carefully explored, so for a time he devoted himself to paleontology. While his salary as professor was ample for his own support, it was not what would be called generous at the present time, yet Müller became so devoted to his science that he paid certain of the workmen to be on the lookout for fossil remains for him in the quarries of the Eifel. He became deeply interested, too, in life in the sea and made his vacations times of specially hard work, investigating the conditions of low life among marine organisms. He passed from one class of life to another. From sea-urchins and starfish to infusoria and polycystina, whose varieties he was himself the first to recognize and describe.
Müller was one of the first to point out that certain of the lower animals could propagate similar and dissimilar [{238}] generations, that is, reproduce by alternate generations. He studied and demonstrated especially the metamorphoses in the echinodermata, and his broad vision and careful observation in this new and surprising scientific field cleared up many things that had been mysteries before.
In paleontology Müller worked with our own Agassiz, then a young man, or perhaps it should rather be said that Agassiz worked with Müller. A paper, for whose compilation they made a series of observations together, appeared at Neufchatel, in 1834. It was a note on the vertebrae of living and fossil dog fishes. At this time Müller was interested in fossil fishes of many kinds and wrote several articles in later years on this subject. Toward the end of Müller's life he studied especially the polycystina, certain of the radiolaria, and some of the many chambered specimens, fossil and living, that were attracting much attention at that time. As a matter of fact he went the day before his death to the zoological museum of Professor Peters in Berlin, in order to obtain some polythalamacea.
How open to advance in science and how ready to encourage the work of others Müller was, may be gathered from his attitude to parasites as the cause of disease, when these began to be discovered. After Professor Schoenlien's discovery of the parasite of favus, Müller became interested in it, confirmed Schoenlein's observations and added something to our knowledge of it. About this time, also, he discovered the psorosperm as a parasite of animals and possibly of man, and devoted considerable attention to it. His work was afterward greatly extended by one of his pupils, Lieberkühn, whose researches with regard to these minute organisms attracted the attention of the medical world.
It is not a little surprising how many of the investigations that afterward were to give fame to Virchow were initiated [{239}] by his great teacher, Müller. It was Müller whose study of tumors led Virchow to devote himself to this subject and give us the best pathological work on it that has ever been written. Virchow himself notes with regret that Müller turned aside from pathology and never finished the promised work which was to have contained his theory of the origin of tumors. Another work in which Virchow followed in Müller's footsteps was the development of craniometry and, in general, the scientific investigations of skulls. Müller had interested himself very much in microcephalic skulls and Virchow assisted him in the investigations of them. Many years afterward Virchow established the science of craniology in the department of anthropology, and succeeded in throwing not a little light on the origins of races by his discoveries in this matter.
After Schoenlien's discovery of the parasite of favus, Müller became interested in the parasitology of human beings, and with Retzius, the famous Swedish anatomist, investigated certain molds which occur in the respiratory passages of birds. They succeeded in demonstrating that these vegetable parasitic growths were a form of Aspergillus. Their studies in the white owl particularly called general attention to the possibility of such molds occurring as parasites of animals. Later on, Virchow showed that these same molds occur occasionally in the respiratory passages of men. Virchow found them in three bodies at autopsy, all of them being run down individuals, two of them old subjects, and all sufferers from chronic bronchitis. Usually, when the parasites were found, there was a distinct tendency to very low resistive vitality in the tissues, sometimes proceeding even to the extent of beginning pulmonary gangrene. In reviewing the subject Virchow [Footnote 7] said that the light thrown [{240}] upon it by the investigations of Müller and Retzius was of the greatest possible assistance in enabling him to identify the parasite when he found it in human subjects.
[Footnote 7: Virchow's Archiv, Bd. ix.]
The number of positive facts which Müller brought to light in the most diverse departments of science is almost beyond calculation, and yet it is astonishing how seldom the slightest error, or even an incomplete observation, can be found in his work. On the other hand, it has happened, over and over again, that when the correctness of his observations in the beginning seemed according to other investigators to be dubious, they have come eventually to be acknowledged as representing the truth. As a rule, he went over every set of observations three times. During the second series he wrote about them. He always repeated the experiments on which his observations were founded while his material was going through the press. His manuscripts were a mass of corrections; notwithstanding this, his proof sheets were the despair of the printers.
Müller accomplished all this only by the most careful husbanding of his time. He knew how to make use even of the ends of hours and brief intervals which others waste without a thought about them. He used to call these periods of short duration between the duties "the gold-dust of time," and said that he did not wish to lose a particle of it. In the quarter of an hour between two lectures it was not an unusual thing to find that he took up some dissection at which he was engaged, or continued his work sketching the observations that he had been making during the previous day.
How thorough was Müller's work in everything that he devoted himself to can be gathered from certain excursions into pathology, which was, after all, only a side issue in his work, and to which he gave very little serious attention. Müller's assistant in the Museum of Berlin, and one of his [{241}] favorite pupils, Schwann, made a series of what Virchow calls comprehensive and magnificent investigations on the cell structures of the animal tissues, on which progress in pathology so essentially depends. Müller followed up these discoveries, and, to quote Virchow once more, he was in this matter the authority of authorities; for the medical world owes to him practically all its knowledge of tumors. Müller first demonstrated the harmony which existed between the pathological and the embryonic development of tumors.
This physiological observation is of the highest importance. It came at a time when tumors were considered to have nothing of the physiological about them, but to be entirely manifestations of morbid processes foreign to all natural functions of the body. Müller's observation of the identity of the pathological and the embryonic development of tumors is really the key to the whole doctrine of morbid formations. Virchow assures us that Müller's labors gave the strongest impulse to the employment of the microscope in pathological investigations. Undoubtedly this was his most important contribution to scientific medicine. With this he laid the foundation of the explanations of tumors--a work that his great pupil was destined to carry on. Some of Müller's work in this line, his study of enchondromata for instance, Virchow confesses to have been part of the inspiration that led to his own later work. Müller was occupied, however, with too many things to devote himself to the study of pathology in the way that would have been necessary to make great discoveries in the science. He promised that he would sometime settle down to make a classification of tumors, and that the principle of such a classification would not be based either on their fineness of structure or on their chemical composition, but that their physiological nature and tendency to grow must be taken into account. When he died, however, he [{242}] left behind him nothing unfinished except the long-expected conclusion of his book on tumors.
Müller's most important work in physiology, and his most far-reaching influence on the biological sciences, which were just then beginning their modern development, came from his assertion of vital force as a thing entirely different from and absolutely independent of the physical or chemical forces which it directs and makes use of. Vital force for Müller was the ultimate cause and supreme ruler of vital phenomena, so that all the energies of an organism follow a definite plan. It was for him the complete explanation of all the physical manifestations of life. It disappears in death without producing any corresponding effect. Without losing anything of itself it hands over in multiplication or reproduction a force equal to itself to the new being that is born from it. This vital force that is thus handed over need not necessarily manifest itself at once, but may lie dormant for a long time to be awakened to manifestations of life by the concurrence of proper conditions in its environment.
In a word, Müller appreciated fully the mystery of life, faced the problem of it directly, stated it in unequivocal terms, and by so doing saved the rising science of biology from wandering off into speculations which were seductive enough at that time, but which would have proved vain and wasteful of time and investigative energy. Müller's influence on his students was sufficient in this matter to set the seal of vitalism, as it is called, on most of the biological work done in Germany about the middle of the century, and it was a recurrence to his observations and his methods which led the reaction to vitalistic theories that characterized the concluding years of the nineteenth century.
With regard to the significance of Müller's work, Professor Du Bois-Reymond, himself a pupil of Müller, in his memorial [{243}] address delivered before the Royal Academy of Sciences of Berlin in 1859, [Footnote 8] says: "It has been objected by those who insist on the greatness of Müller's reputation that he himself made no discovery that can be said to be of the first rank. Müller's fame is great enough for us to allow that there is something true in this objection. He accomplished more in developing the ideas of others than in original research of his own. That he did not make any great discovery is, however, rather due to the fact that he came at a time when great discoveries were no longer lying around loose as they had been in the preceding century, waiting to be made, as it were; and what he accomplished was of more value than one or two single discoveries of primary importance. He made the original ideas of other men so clear that they were at once accepted by all the medical and scientific world. In this way he furthered the progress of medicine better than any devotion, however successful, to one single feature could possibly have accomplished.
[Footnote 8: Gedächtnissrede auf Johannes Müller, von Emil Du Bois-Reymond, Berlin, Buckdruckerei der Königlichen Akademie der Wissenschaften (Dummler), 1860.]
"Müller made mistakes, but then who ever fails to make mistakes in the face of nature? As a rule, however, he hit the nail on the head. There are many suggestive thoughts from him that the investigators of later times have proved to be true. He suggested, for instance, that there must necessarily be some connection between the ganglionic bodies and the nerve stems. He suggested, also, that there must be a special nerve system for the intestinal tract. Later discoveries in physiology have established both of these thoughts and have shown that Müller had so entered into the spirit of nature and her processes as to be able to think her thoughts. There is no doubt that there are suggestions in [{244}] his writings, especially those of the later years of his life, which will give a series of triumphal substantiations of the same kind."
Du Bois-Reymond's final judgment is of special interest, because it tries to point out the comparative place that will be occupied by three great men in the biological sciences of a century ago:
"Haller and Müller must be considered as giants of earlier days, though when future generations compare them with Cuvier they will occupy somewhat of the position that Galileo and Newton hold in comparison to La Place and Gauss, or Lavoisier in comparison to Berzelius. The first of these men had the opportunity to do great things while it was yet possible to do them, and left to their successors only the possibility of developing their thoughts." [Footnote 9]
[Footnote 9: Some idea of the estimation in which Müller was held by his contemporaries, German and foreign, may be gathered from the number of scientific bodies of which he was a member. He was an associate in practically every serious scientific body in Germany. He was, besides, foreign member of the scientific academies at Stockholm, Munich, Brussels, Amsterdam; the scientific societies of Göttingen, London, Edinburgh, Copenhagen; foreign honorary member of the Academy of Sciences of Vienna; corresponding member of the Academies of St. Petersburg, Turin, Bologna, Paris and Messina; of the Society for Science at Upsala, of the Mecklenburg Naturalist Society of Rostock, of the Senkenberg Institute of Frankfort-on-Main, of the Academy of Natural Sciences of Philadelphia, of the Society of the Museum of Natural History at Strasbourg, of the Naturalists' Association of Dutch East India; member of the Holland Society of Sciences, Haarlem; of the Naturalist Society of Frieburg in Breisgau, Halle, Dantzig and Mainz; of the American Philosophical Society of Philadelphia, of the Society of Biology of Paris; honorary member of the Cambridge Philosophical Society, of the Natural Science Union of Hamburg, and the Natural Science Association of the Prussian Rheinland and Westphalia, of the American Academy of Arts and Sciences in Boston, of the Ethnological Society of London, of the Microscopic Association of Giessan, member of the Society for Science and Medicine at Heidelburg, of the Naturalists' Society at Dresden; corresponding member of the Scientific and Medical Association of Erlangen and Moscow; member of the Academy of Medicine of Paris; honorary member of the Academy of Medicine of Prague and of Dorpat, of the Medico-Chirurgical Academies of Wilna and of St. Petersburg, of the Medical Society of Guy's Hospital in London, of the Medical Society of Edinburgh and of the Hunterian Society of the same city, and of the Medico-Chirurgical Societies of London and of Zurich, of the Medical Societies of Budapest, of Lisbon, of Algiers and Constantinople; corresponding member of the Medico-Chirurgical Academy of Turin and of the Medical Society of Vienna.
Even this long list does not include all his various honorary and active memberships in scientific and medical societies. He was, besides, the laureate, that is, a prize winner, of the Medical Faculty of the University of Bonn, of the Sömmering Prize of the Senkenberg Institution, of the Copley Medal of the Royal Society of London, of the Culver Prize Monthyon of the same institution, as well as laureate of the Academy of Sciences of Vienna for Experimental Physiology. He had been honored by the King of Prussia by the conferment of the knighthood of the Order of the Red Eagle, by the King of Sweden by the Royal Swedish Order of the North Star, by the King of Bavaria by the Royal Bavarian Maximilian Order, and by the King of Sardinia by a knighthood in the Order of SS. Mauritius and Lazarus.]
It is as a teacher that Müller did his best work. He was not by nature a good talker and never said much, but he was very direct; and, as he spoke from the largest possible and most progressive knowledge of the subject, his lectures were always interesting to serious students. There seems to be a more or less general agreement that for the mass of his students he was uninteresting because likely to be above their heads. For the talented members of his class, however, he was an ideal teacher--always suggestive, always to the point, and eminently complete. Du Bois-Reymond says that he never was confused, never repeated himself, and never contradicted himself.
He was able to illustrate his lectures by sketches on the board in a way that enabled students to follow every step of [{246}] even a complex, embryological developmental process. He could trace, step by step, with the chalk, every stage of evolution in the organism and bring it clearly before his students. To a narrow circle of the best men within his class he became a personal friend, whose inspiration led them on to the deepest original researches. Among his students were some of the men who made German medicine and German science known all over the world in the last fifty years. Chief among them may be mentioned Virchow, Helmholtz, Du Bois-Reymond, Schwann, Lieberkuhn, the discoverer of the follicles in the intestines; Max Schultze, whose work in histology and physiology are well known; Claparede, Remak, Guido, Wagener, Lachmann and Reichert.
What he demanded of his students above all was that they should learn to help themselves. He set them tasks, gave them suggestions, directed their work, corrected their errors, but he wanted them to do work for themselves. His very presence was an inspiration. Both Virchow and Du Bois-Reymond speak of the power of his eye. Du Bois-Reymond says that there was in him an almost demoniac magic, and that students looked to him as the soldiers of the first Napoleon did when the great Emperor's words were in their ears--"Soldiers, the Emperor has his eye on you." Du Bois-Reymond adds that, consciously or unconsciously, every student felt the winning influence of his great personality. With all this he knew how to unbend, especially with favorite students, and many a joke from him found its way around the laboratory even during working hours. He was not one to stand on his dignity, and Virchow tells of him that even when nearly fifty he was known to race with a student down the corridor from one class-room door to another. He took up skating at the age of forty-five, and though he had not many friends and was too entirely devoted to his work to make [{247}] many acquaintances, it was always a source of pleasure to young men to be allowed to associate with him, and many eagerly sought the privilege.
How impressive a figure Müller made in his character of teacher can be gathered best, perhaps, from a note added to Virchow's panegyric during its progress through the press, in which the pupil tells his impressions of the master:
"I must confess that Müller, in his lectures and in his manner, reminded me of a Catholic priest, which might be accounted for by the impressions of his early childhood. When as the dean of the Faculty he mounted the cathedra superior, dressed in his official robes, and pronounced the Latin formulary of the proclamation of the doctors of medicine, with short, broken and contracted words; when he began his ordinary lectures in almost murmured syllables; or, when with religious earnestness he was discussing any of the abstruse questions of physiology, his tone and manner, his gestures and looks, all betrayed the traditional training of the Catholic priest."
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.