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 assistants; 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 assistant 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 assured. Their promotion seldom comes from the institution 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 Löwen, 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, Löwen, 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.
[Footnote 11: Mikroskopische Untersuchung über die Uebereinstimmung in der Structur und dem Wachsthum der Thiere und Pflanzen, 1839.]
At Louvain, Schwann remained for about ten years. The period is marked by a continuance of his fruitful investigation of cell-life, of the physiological biology of ferments and fermentation, and of the allied subject of digestion in animals. His researches in Berlin on this interesting and important subject, which was practically a complete mystery at that time, had been mainly concerned with the gastric juice. He now began the study of various secretions which aid intestinal digestion. He proved that bile, which used to be considered an excretion, was really an important digestive secretion. He was not able to demonstrate the function of bile as completely as he had done for the gastric juice. The problem of intestinal digestion is much more complicated than that of stomach digestion, and involves a number of factors for which allowance has to be made if the value of any one of them is to be accurately determined. Even in our own day all of the physiological problems in the functions of biliary secretion are not solved. The greatest step was the demonstration that bile is a thing whose presence in the intestines is to be encouraged, not because, as Horace said, mental trouble was imminent unless one were purged of black bile in the springtime, but because its presence insures the proper preparation of food, and neutralizes in the intestinal tract certain poisonous substances that if absorbed would prove sources of irritation to all higher tissues.
His work on bile practically closes Schwann's career as an investigator. The seven years between twenty and [{266}] twenty-seven were so full of discovery that there seemed to be great promise for his mature years. Had Schwann died at thirty his biographies would have surely contained lengthy comments on the great discoveries that would undoubtedly have rewarded his efforts in the prime of his powers. Schwann's seeming inactivity has been a fruitful cause for conjecture. The fact of the matter is, however, that original work of a high order is accomplished mainly during the time when activity of the imagination is at its height. There are very few cases in which this acme of inventive effort has lasted more than ten years.
Besides this there were certain more material factors that hindered original work. Schwann was a German, yet had to give his lectures at Louvain in French. For several years most of his efforts were devoted to acquiring facility in the language of his adopted country. Then Schwann was not such a teacher as Müller, but the true pedagogue who took seriously to heart the duty of teaching all his students. To do this meant, in the rapidly advancing science of that day, unceasing toil on the part of a conscientious professor. For it was a time of great discoveries succeeding one another with almost incredible rapidity. For ten years Schwann faithfully devoted himself to his teaching duties in the anatomical course at Louvain. He then accepted the chair of comparative anatomy and physiology at Liège, where he continued to lecture for thirty years. As the result of his stay at Louvain there has always been special attention given to biological studies at that university. At the present time there is published there a very well and favorably known biological journal, La Cellule, through which many important contributions from the professors and students of the university find their way before the public.
During his stay at Liège Schwann was formally invited, [{267}] on three different occasions, to return to his German Father-land to become professor at some of her great universities. Professorial chairs in anatomy or physiology at Würzburg, at Giessen, and at Breslau, were offered him between 1850 and 1860. He refused them, however, to continue his work in Belgium. He found his adopted countrymen eminently sympathetic. It seems clear that he felt more at home in the midst of the profoundly Catholic sentiment that pervaded the Belgian universities, and which was in such marked contrast to the rationalistic spirit characteristic of the German universities at that time. Schwann was penetrated with a lively sense of the deepest religious feeling, which is noticeable all through his life. His attitude in this matter greatly impressed his scientific contemporaries. His sense of duty in matters spiritual was only equalled by his affectionate regard for his relatives. His vacations were invariably spent with his parents while they were alive, and later with his brothers and sisters in the neighborhood of Cologne. It was while making a Christmas visit to them that he suffered the fatal stroke which carried him away.
Toward the end of his career Schwann was invited to be a member of a commission to investigate the case of Louise Lateau. It will be remembered that the report of recurring bleedings from stigmata in this case attracted a great deal of attention, not only among Catholics, but among all classes throughout the world. After careful observation Schwann refused to concur in the report that the bleedings were manifestly miraculous. At first it was announced that he had declared them evidently beyond the domain of natural causes, but this report he took occasion to correct immediately. The circumstance led to the publication of some harsh words in the religious press, but with his usual moderation Schwann refused to enter into any discussion, and so the affair ended. [{268}] His thoroughly conservative attitude in the matter, and his application of the strictest scientific criteria to the case, prevented formal expression of approval on the part of those in authority. While such an opinion would have carried only personal weight with it, it might easily have been made a cause for unfortunate aspersions upon the Church.