Makers of Modern Medicine Part 14

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 Sommering Prize of the Senkenberg Inst.i.tution, of the Copley Medal of the Royal Society of London, of the Culver Prize Monthyon of the same inst.i.tution, 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.]

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It is as a teacher that Muller 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 ma.s.s of his students he was uninteresting because likely to be above their heads. For the talented members of his cla.s.s, 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 ill.u.s.trate 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 cla.s.s 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 cla.s.s-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 a.s.sociate with him, and many eagerly sought the privilege.

How impressive a figure Muller 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 Muller, 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 p.r.o.nounced 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, "Muller 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 Muller, one of the earliest teachers. [Footnote 10]

Helmholtz, Brucke, 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, Muller 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. Muller 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]

Muller'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 Muller for some years, and his temporal artery particularly had become hard and tortuous.

Muller 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 Ma.s.s 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, Muller 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 Muller 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 Muller 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.

Muller 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, Pere 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 Muller, 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.

Muller 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.

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THEODORE SCHWANN, FATHER OF THE CELL DOCTRINE

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My message is chiefly to you, Students of Medicine, since with the ideals entertained now your future is indissolubly bound. The choice lies open, the paths are plain before you. Always seek your own interests, make of a high and sacred calling a sordid business, regard your fellow-creatures as so many tools of trade, and, if your heart's desire is for riches, they may be yours; but you will have bartered away the birthright of a n.o.ble heritage, traduced the physician's well-deserved t.i.tle of the Friend of Man, and falsified the best traditions of an ancient and honorable Guild. On the other hand, I have tried to indicate some of the ideals which you may reasonably cherish. No matter though they are paradoxical in comparison with the ordinary conditions in which you work, they will have, if encouraged, an enn.o.bling influence, even if it be for you only to say with Rabbi Ben Ezra, "What I aspired to be and was not, comforts me."

And though this course does not necessarily bring position or renown, consistently followed it will at any rate give to your youth an exhilarating zeal and a cheerfulness which will enable you to surmount all obstacles--to your maturity a serene judgment of men and things, and that broad charity without which all else is naught--to your old age that greatest of blessings, peace of mind, a realization, maybe, of the prayer of Socrates for the beauty in the inward soul and for unity of the outer and the inner man; perhaps, of the promise of St. Bernard, "Pax sine crimine, pax sine turbine, pax sine rixa."

--Osler, _Teacher and Student, Aequanimitas_.

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THEODORE SCHWANN, FATHER OF THE CELL DOCTRINE.

It is one of the curious features of history that genuine worth of human accomplishment is almost in inverse ratio to the popularity it obtains in the generation in which it is produced. Supremely great work is rarely appreciated at anything like its proper value, by contemporaries. This principle is true apparently in all fields of human endeavor. In literature and in art it is a commonplace. But also, surprising though it may be, in science and in social betterment the rule holds a prominent place. It is nearly always the sign of only pa.s.sing merit when any work secures the plaudits of its own generation. Brilliant theories are often immediately hailed with universal acclaim, while ground-breaking observations that are really great discoveries are apt to be neglected. The really new discovery is so novel that men cannot appreciate it at once. It is so different from their ordinary modes of thinking that they cannot place it properly. Its complete significance fails them.

This has been true for our nineteenth century biology almost more strikingly than for any other department of knowledge. Our many avenues of publicity instead of heralding abroad the great observations as soon as they have been made, in order to enable others to continue the work that the master mind has begun, have been only too constantly crowded with new opinions, novel theories, taking hypotheses, all attracting attention that they did not deserve. Men like Theodore Schwann, the father of the cell doctrine, are not apt to be so well known as the suggestor of some {254} striking bit of theory. Even the great biologists, such as Darwin himself, are known rather for their insubstantial theories than for their substantial additions to biological knowledge by patient observation and genial penetration into the secrets of nature. It is perhaps a warning to the modern physician who realizes this state of affairs, not to take the popular theories even in his own branch of biology as the current coin of truth. Theories pa.s.s, but observations endure. Auenbrugger's new method of tapping the chest in order to elicit its varying sounds looked even more childish than Galvani's acceptance of the position of dancing master to a frog, but their observations thus made continued the germs of undying truth.

While the name and the life of Theodore Schwann are but little known by the general public, his work is very thoroughly appreciated by those who have made special studies in biology, and few men in the progress of that science are considered to hold as high a place as that a.s.signed to him. A study of the life of Schwann will serve to show not only that he eminently deserves this honor which has come to him, but will also bring into evidence the fact that his career deserves to be better known popularly, because it ill.u.s.trates very well the typical mode of life in which great scientists are nurtured and the methods of investigation by which great discoveries are made.

Of the men who have made the biology of the nineteenth century there are three whose names stand out with special prominence. They are noted not for their controversial writing on mooted points, but for ground-breaking, original work of the highest scientific import. Their discoveries will preserve their memories for posterity long after the names of many of those to whom the glare of controversial publicity lent an ephemeral brightness for their own {255} generation shall have been forgotten. They are: Theodore Schwann, the anatomist, to whom modern biology owes its foundation by the establishment of the cell theory; Claude Bernard, the physiologist, to whom we are indebted for the great biological ideas of nervous inhibition and internal glandular secretion; finally Louis Pasteur, the chemist-bacteriologist, to whom is due the refutation of the annihilatory abiologic doctrine of spontaneous generation, and the discoveries that have revolutionized modern medicine and promise to accomplish as great a revolution in modern manufactures and industries.

It has often been said that the Catholic Church is opposed to scientific advance. It has especially been insisted that in what concerns biological science the Church's att.i.tude has been distinctly discouraging. Recently the definite a.s.sertion has been made that no original thinker in science could continue in his profession of faith.

Now, it so happens that all three of these men were born in the bosom of the Catholic Church, and were educated from their earliest years to maturity under her watchful care. Schwann and Pasteur remained in the midst of their great scientific triumphs her faithful sons. For years Bernard withdrew from all his old religious a.s.sociations and became indifferent to the spiritual side of life, but before the end he came back to the knees of the Mother whose fostering care meant so much to him in early life.

Theodore Schwann, the first to formulate the cell doctrine, to promulgate the teaching that all living tissues, whether plant or animal, are composed of a number of minute elements which under all circ.u.mstances are biologically equivalent--is the father of modern biology. Cells had been seen and recognized as such before, but their significance was first pointed out by him. His cell theory has now become the {256} cell doctrine, the teaching of all the schools of biology. The generalization that forms the basis of the doctrine was the result of some of the most accurate and careful observation that has ever been made. The work was done when the mechanical helps to the a.n.a.lysis of tissues were in the most primitive condition. The microscope had just been introduced into general laboratory work. The microtome, the instrument by which tissues are cut into thin sections suitable for microscopic examination, and to which almost more than to the microscope itself we owe our detailed knowledge of the intimate const.i.tution of tissues, was as yet unthought of. Despite these drawbacks Schwann's work was done with a completeness that leaves very little to be desired. He published, when not yet thirty, the story of his comparative investigation of the cellular const.i.tution of plants and animals, and there is very little that can be added, even in our day, to make its scientific demonstration any clearer than it was. It was typical of the man that, heedless of disputatious controversy over details of his work, he should go calmly on to complete it, and then give it to the world in all its convincing fulness. The same trait crops out with regard to other subjects. His was one of the great scientific minds of the century, always immersed in a philosophic calm befitting the important problems he had in hand. His life is ideal in its utter devotion to science, and to the teaching of science, while no duty that could round it out and make it humanly complete for himself or others was despised or neglected.

Theodore Schwann was the fourth of a family of thirteen children, born in the little German town of Reuss, not far from Cologne. He received his college education in the Jesuit Gymnasium of Cologne, and pa.s.sed thence to the University of Bonn. The lower Rhineland is largely {257} Catholic, and to this day, though Bonn has become the fashionable exclusive German university to which the Kaiser and many of the scions of the great German families go for their higher education, the faculty of theology at the university remains Catholic. Schwann devoted some time here to the study of theology, but he came under the influence of Johann Muller, was allowed to a.s.sist in some of his experiments on the functions of the spinal nerves of frogs, and this seems to have determined him to a medical career.

After two years spent in medicine at Wurzburg, another great Catholic university of Southern Germany, we find Schwann at the University of Berlin, once more working with Johann Muller, who had been invited from Bonn to fill the distinguished Rudolphi's place in the chair of anatomy at the rising Prussian university. Muller was one of those wonderful men--they turn up, unfortunately, all too rarely--who, though not great discoverers themselves, have the invaluable faculty of inspiring students with an enthusiasm for original observation which leads to the most brilliantly successful researches. A great teacher, in the proper sense of the word, he was not. In his public lectures and his ordinary lessons he was often arid and uninteresting, insisting too much on unrelieved details, "the dry bones of science."

He seems to have failed almost completely in conveying the usual scientific information of his course with the air of novelty that attracts the average student. The true teaching faculties are not given to many. Muller had a precious quality all his own that has proved much more valuable for science than the most enlightened pedagogy.

To the chosen few among his students who were drawn into close intimacy with him and permitted to share his personal scientific labors, Muller proved a source of most precious incentive--a suggestive master, the inspiration of {258} whose investigating spirit was to be with them throughout life. To no one, except perhaps to Socrates of yore, has it been given to have sit at his feet as pupils so many men who were to leave their marks upon the developing thought of a great era in human progress. Beside Schwann, there studied with Muller, during these years at Berlin, Henle the anatomist, Brucke the physiologist, Virchow the pathologist, Helmholtz the physicist, Du Bois-Reymond the physiologist, Claparede, Reichert, Lachmann, Troschel, Lieberkuhn and Remak. All these names are writ large in the scientific history of the century. It is a remarkable group of men, and of them Schwann, with the possible exception of Helmholtz, will be remembered the best by posterity; certainly none of them would not have cheerfully resigned his hopes of scientific renown for any work of his own to have made the discovery which, as an enthusiastic biographer said, set the crown of immortality on a young, unwrinkled forehead.

Schwann's thesis for his doctorate at Berlin showed the calibre of the man, and demonstrated his thorough fitness for success as an experimental scientist. The question whether the growing embryo in the ordinary hen's egg consumes oxygen or not had been in dispute for some time. It was well known that an air-chamber existed in the egg even at the earliest stages of embryonic life. It was understood that the mature chick just before its egress from the egg must have air, and the porosity of the egg-sh.e.l.l was sufficient to permit its entrance.

Whether at the beginning of embryonic life within the egg, however, oxygen was necessary, remained somewhat in doubt. It had been demonstrated that the gas existing in the air-chamber of an egg became changed in composition during the progress of development. From being slightly richer in oxygen than ordinary atmospheric air at the beginning of embryonic growth, {259} containing 24 to 25 parts of oxygen per 100, it became modified during comparatively early development so as to contain not more than 17 parts of oxygen per 100 and some 7 parts of carbon dioxide. This change of composition was, at least, very suggestive of the alteration that would take place during respiration. It was pointed out, however, that the argument founded on these observations was drawn only from a.n.a.logy, and was by no means a scientific demonstration of the fact that the embryo not only consumed air during its growth, but actually needed oxygen for the continuance of its vital processes.

It was suggested that the change of composition in the air within the egg might be due not to any essential vital functions, but to chance alterations brought on by decomposition in the unstable organic material so abundantly present in the substance of the egg. Schwann settled the question definitely by a set of ingenious experiments. He exposed eggs for various periods to the action of other gases besides air, and also placed them in the vacuum chamber of an air-pump. When not in contact with the air the eggs developed for some hours if the temperature was favorable, and then development ceased. If after twenty-four hours' exposure to an atmosphere of hydrogen eggs were allowed free contact with the air, development began once more at the point at which it had ceased. After thirty hours of exposure to hydrogen, however, or to the vacuum, all life in the egg was destroyed, and it failed to develop no matter how favorable the conditions in which it was afterward placed. The completeness with which the points in dispute in this problem were demonstrated is typical of all Schwann's work. His conclusions always went farther than the solution of the problem he set out to solve, and were always supported by simple but effective experiments, often ingeniously planned, {260} always carried out with a mechanical completeness that made them strikingly demonstrative.

One of Schwann's brothers had been a worker in metal, and Schwann himself had always shown a great interest in mechanical appliances.

This hobby stood him in good stead in those days when laboratories did not contain all the intricate scientific apparatus and the facilities for experimentation so common now, with their workshop and skilled mechanics for the execution of designs. Many another worker in the biological sciences of that time owes his reputation to a similar mechanical skill. Experiments were impossible unless the investigator had the mechanical ingenuity to plan and the personal handiness to work out the details of appliances that might be necessary for experiments. It is told of Schwann that when Daguerre's discoveries in photography were announced, such was his interest in the new invention that he made a trip to Paris especially to learn the details of the method. Some daguerreotypes made by him according to the original directions of the inventor himself are still preserved by his family.

Schwann's investigation of the respiration of the embryo in hens' eggs led to further studies of the embryo itself, and to the discovery that it was made up of cells. Later came the resolution of other tissues into cells. When, after his graduation as doctor in medicine, the post of a.s.sistant in anatomy at Berlin fell vacant, it was offered by Johann Muller to Schwann. The position did not carry much emolument with it. The salary was ten German thalers--_i.e._, about $7.50 per month--a pittance even in those days when the purchasing power of money was ever so much greater than now. His duties took up most of his time. The work was congenial, however, and Schwann remained here for five years. As Henle has said in his biographical sketch of {261} Schwann, in the _Archiv f. mikroskopische Anatomie_, just after his death in 1882: "Those were great days. The microscope had just been brought to such a state of perfection that it was available for accurate scientific observations. The mechanics of its manufacture had besides just been simplified to such a degree that its cost was not beyond the means of the enthusiastic student even of limited means.

Any day a bit of animal tissue, shaved off with a scalpel or picked to pieces with a pair of needles or the finger-nails, might lead to important ground-breaking discoveries." For at that time almost everything as to the intimate composition of tissues was unknown.

Discoveries were lying around loose, so to speak, waiting to be made.

Schwann was not idle. The precious years at Berlin saw the discovery that many other tissues were composed of cells. The nuclei of the striped and unstriped muscles were found, and while the cellular character of these tissues was not demonstrated, their secret was more than suspected and hints provided for other workers that led very shortly to Kolliker's and Henle's discovery of muscle cells.

Besides his interest in histology, the branch of anatomy which treats of the intimate const.i.tution of tissues, Schwann was working also at certain general biological questions, and at some knotty problems of physiology. Not long after his installation as an a.s.sistant at Berlin, from observations on fermenting and decomposing organic liquids, he came to a conclusion that was far in advance of the science of his day. He announced definitely _infusoria non oriuntur generatione aequivoca_--the infusoria do not originate by spontaneous generation.

Under the term infusoria, at that time, were included all the minute organisms; so that Schwann's announcement was a definite rejection of the doctrine of spontaneous generation over thirty years before Pasteur's demonstrations finally settled the question. Schwann was never a {262} controversialist. He took no part in the sometimes bitter discussions that took place on the subject, but having stated his views and the observations that had led up to them he did not ask for the immediate acceptance of his conclusions. He continued his work on other subjects, confident that truth would prevail in the end. When the congratulations poured in on Pasteur for having utterly subverted the doctrine of spontaneous generation, the great French scientist generously referred the pioneer work on this subject to Schwann, and sent felicitations to that effect when Schwann was celebrating the jubilee anniversary of his professoriate.

While studying ferments and fermentations Schwann became interested in certain functions of the human body that carry with them many reminders of the biological processes which are at work in producing the various alcohols and acids of fermentation. The changes that occur in the contents of the human stomach during the preparation of food for absorption had long been a subject of the greatest interest to physiologists. It had been studied too much, however, from the merely chemical side. The necessity for the presence of an acid in the stomach contents in order that digestion should go on led to the conclusion that the acid was the most important const.i.tuent of the gastric juice. By means of the sc.r.a.pings of the stomachs of various animals Schwann succeeded in preparing an artificial gastric juice, and showed just how the action of the gastric secretions brought about the solution of the contents of the stomach. He isolated pepsin, and demonstrated that it resembled very closely in its action the substances known as ferments. He even hinted that digestion, instead of being a chemical was a biological process. Any such explanation as this was scouted by the chemists of the day, headed by Liebig. Most of the physiological functions within the human body were {263} then triumphantly claimed as examples of the working of chemical laws.

Of the contradiction of his conclusions Schwann took practically no notice, but went faithfully on with his work. He could not be lured into controversy. For nearly five years he continued his work at the University of Berlin, receiving only the pittance that has been mentioned--less than ten dollars per month. Only the purest love of science for its own sake, and the satisfaction of his own enthusiastic spirit of investigation kept him at work. There was but little prospect of advancement at the University of Berlin itself. Schwann was one of the lowest in rank of the a.s.sistants; the professor was only just beyond the prime of life; and before Schwann on the list for promotion was at least one man, Henle, who had already done distinguished work. Germany had the good fortune to have all during the nineteenth century young men who, unmindful of present emolument, had been satisfied with the scantest wages for their support, provided the positions they occupied gave them opportunities for original work.

Even at the present day young medical men are glad to accept what they consider the honor of the position of a.s.sistant to the professor and director of the clinic, and to remain in it for from five to ten years, sometimes even more, though the salary attached to it is only from $250 to $400 per year. They well know that if their original investigations into various medical questions are successful, advance in university rank is a.s.sured. Their promotion seldom comes from the inst.i.tution where they have done their work, unless it should be one of the smaller universities; but the invitation to a chair at a university will come sooner or later for meritorious research.

Schwann's invitation came from Louvain. His work on cells had attracted a great deal of attention. In the midst {264} of the rationalism and infidelity then so common among scientific men Schwann was known as a faithful, sincere Catholic. When the great Catholic University of Louvain, then, looked around for a professor of anatomy, he appeared to be the most suitable person. Henle, who had very little sympathy for Schwann's religious views, speaks most kindly of him as a man and a comrade. Schwann seems to have endeared himself to the "difficult" Prussians, as he did to those around him all his life. For the dominant note in the sketches of him by those who knew him personally is that of heartiest friendship, joined with enthusiastic admiration for his simple sincerity and unselfish devotion to his friends and to science.

A little incident that has been preserved for us by Henle shows how much his young contemporaries appreciated even at that early date, long before the full significance of the cell theory could be realized, the aspect of Schwann's work which was to make him immortal.

At a little farewell dinner given him by his co-workers in various laboratories of the University of Berlin the feature of the occasion was a punning poem, by the toast-master, on the words Louvain and cells.

In German Louvain is Lowen, which also means lion; that is, it is the dative case of the name of the lion. Reference is made to the fact that as Samson found honeycomb (in German, bee-cells) in the lion, so now Louvain--_i.e._, in German, Lowen, the lion--finds a champion in the man of the cells. As Samson's riddle was suggested by finding the bee-cells, so will the new professor at Louvain solve the riddles of science by the demonstration of cells. The youthful jesting seer prophesied better than he knew. Schwann's first completed work at Louvain was the _Microscopical Researches into the Accordance in Structure and Growth of Plants and Animals._ [Footnote 11] {265} The theory it advanced was to prove the most potent element thus far introduced into biological science to help in the solution of the difficult problems that constantly occur in the study of the various forms of life.