Tuesday, March 17, 2009

Theodore Schwann

Theodore Schwann is "the great discoverer" of cells, "in whom we find a rare union of consummate talent for research and religious fervour" [Kneller] Schwann was a student of Johann Müller, whom we saw recently.

Dr. Walsh has an entire chapter on his work, from which the following is excerpted:
Men like Theodore Schwann, the father of the cell doctrine, are not apt to be so well known as the suggester of some 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.

Johann Müller's assistant in the Museum of Berlin, and one of his 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.

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 circumstances 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 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 analysis 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 constitution 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 constitution 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 1810 in the little German town of Reuss, not far from Cologne. He received his college education in the Jesuit Gymnasium of Cologne, and passed thence to the University of Bonn. The lower Rhineland is largely 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 Müller, was allowed to assist 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.

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 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.

Besides his interest in histology, the branch of anatomy which treats of the intimate constitution 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 assistant 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 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.

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.

[Walsh, Makers of Modern Medicine]

One more amazing fragment from Kneller, who quotes Schwann himself:
[Schwann] criticises with equal sharpness the vital force of the vitalists and the atheism of the materialists:
"I have never been able to understand the idea of a simple force which is assumed to be capable of altering its mode of action, although not endowed with the faculty of reason. I have always preferred to find the source of that purposiveness, of which the whole course of nature gives conclusive evidence, not in the thing created, but in the Creator..."
Ten years before his own death Schwann delivered the memorial address over a distinguished colleague and countryman, Friedrich Anton Spring (+ 1872), Professor of Physiology at the University of Liège. ... Like Schwann, he obtained a position abroad, and by his scientific achievesnents and his lovable character overcame the natural distrust with which strangers are greeted, and won universal respect and admiration. Spring was at one with Schwann in his attitude towards religion. "If he looked to the future with hope", says the latter, speaking of Spring's last illness, "it was because he did not leave God out of his reckonings. For, gentlemen, I must not and will not pass by the matter in silence, Spring was a man of a profoundly religious mind; he made no ostentatious parade of his faith, but he would have thought it disgraceful to deny it; and when occasion demanded he made open declaration of it. He lived a Christian, and a Christian he died. His supreme consolation was the certainty he had that he would meet again in a better world those whom he had loved in this."
Schwann died in 1882, in Cologne, unwaveringly loyal to the faith in which he had lived.
[Kneller, Christianity and the Leaders of Modern Science]
Note his name is given to the "Schwann cells" which form the "myelin sheath" - the insulation of certain long nerves.


Post a Comment

<< Home