Popular Science Monthly/Volume 13/July 1878/Sketch of Professor Du Bois-Reymond

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THE name of Du Bois-Reymond stands high among that group of illustrious scientific men of whom Germany may well be proud. He is known throughout the scientific world for his masterly researches in experimental physiology, having, while yet a young man, made a series of brilliant discoveries in electro-physiology, which at once placed him at the head of that delicate and important branch of investigation.

But the customary channels of international scientific communication have hitherto been so narrow that the public has not yet been able to recognize his greatness as a thinker on high questions of scientific philosophy. We do not say that Prof. Du Bois-Reymond is more than a scientist, for, in our view, that is a term of great breadth, but we do say that he is much more than a scientific specialist. He is a comprehensive and cultivated thinker. For largeness, originality, and independence of view, for depth of analysis and thoroughness of erudition, and for clearness, vividness, and vigor of style, he has no superior among his distinguished German contemporaries. His celebrated address on "The Limits of our Knowledge of Nature," which attracted great attention in Europe, was first presented to the English-speaking public in The Popular Science Monthly for May, 1874; and we now offer another of his productions to our readers, which is the subject of comment elsewhere. Prof. Du Bois-Reymond is in the vigorous maturity of his life, and, although he has done a great deal of valuable work, much more is still expected from him. We hope in due time to bring before the American public some other of his able productions that are suited to popular appreciation.

Emil du Bois-Reymond was born in Berlin, November 7, 1818. His father, a native of Neufchâtel, in Switzerland, had in his youth been a watch-maker, but subsequently entered upon a literary and official career in Berlin. Du Bois-Reymond's mother was descended from the Huguenots, who were driven from their country by Louis XIV. Among his maternal ancestors we must not omit to mention the celebrated artist and engraver, Daniel Chodowiecki, called by some the Hogarth of Germany.

After the fashion prevalent in Germany, Du Bois-Reymond first attended a primary school, then the Collége François of his native town; but, when he was about eleven years old, his parents went to live several years in Switzerland, and during this period he was a pupil of the College of Neufchâtel. The French language, therefore, was from his childhood as familiar to him as German.

Later on, we again find Du Bois-Reymond in Berlin; and at the age of eighteen he became a student at the university of that town. It is said that, like many others who afterward distinguished themselves in natural science, he first devoted himself to theological studies, and that, during a session, he regularly attended Neander's lectures on ecclesiastical history. Chancing, however, to enter the lecture-room of the celebrated chemist Mitscherlich, he felt irresistibly drawn toward his true vocation. He now studied chemistry, natural philosophy, mathematics, and during the summer of 1838, which he spent at Bonn, on the Rhine, also geology, without any very definite aim.

This was eventually pointed out to him by a friend, the late Dr. Edward Hallmann, who, with greater scientific experience, convinced him that, of all the branches of science, the study of animated Nature affords the highest interest and includes the deepest problems, and that medicine is the proper road to that goal. A medical student, then, Du Bois-Reymond became, and as such, a pupil, and soon after an assistant of the great anatomist and physiologist, John Müller.

The connection with Müller decided, as it were, his fate. Humboldt at that time received a copy of Matteucci's "Essai sur les Phénomènes electriques des Animaux," and communicated it to Müller. Müller, knowing that Du Bois-Reymond possessed a share of physical and mathematical knowledge very unusual in a student of physiology, thought him qualified to take in hand the investigation of animal electricity, in which Matteucci had made but a poor advance since Nobili's discovery of the so-called current of the frog. Thus it happened that, in the spring of 1841, Du Bois-Reymond undertook to elucidate the problem proposed to science by Nobili, and for nearly forty years he has not ceased to work upon this subject, which, in his hands, and those of his numerous pupils, has marvelously expanded, so as to become one of the most important branches of physiology.

Du Bois-Reymond, after having in 1842 printed a short account of his first results, went on working patiently for seven years, and then published his celebrated book, "Researches in Animal Electricity" (Berlin, 2 vols., 1848-'49). This work, besides a complete history of what had previously been done upon the subject, contains an immense number of experiments, made after methods, and with the aid of apparatus, for the most part entirely new, invented by Du Bois-Reymond himself. In substance, the book is devoted to the exposition of his discoveries of the muscular and of the nervous current, of their law, and of the variations they undergo when the muscles and nerves are thrown into action.

To understand the importance of these discoveries, it must be borne in mind that, long before Du Bois-Reymond, in fact since the middle of last century, innumerable attempts had been made to observe electrical phenomena during the contraction of the muscle. They had all failed. Du Bois-Reymond, at the outset, perceived that one of the reasons of these failures was the transient nature of the contraction, and he invented the method of tetanizing the muscles in order to increase the duration of the contraction, and thereby facilitate the observation of what takes place in that state. He was thus fortunate enough to detect electrical phenomena concomitant with the act of contraction, and he even taught how to deflect the magnetic needle of the galvanometer by the voluntary contraction of the muscles in living man, or, as it were, by our will. The correctness of these facts having been doubted by MM. Despretz and Becquerel, of the Académie des Sciences, Du Bois-Reymond, in 1850, went to Paris with his apparatus, and triumphantly proved the truth of his statements.

As to the nerve, up to the date of Du Bois-Reymond's researches, no material change had ever been observed during its activity. In this case, too, a great many fruitless attempts had been made to discover some electrical phenomenon connected with that state. Du Bois-Reymond constructed with his own hands a galvanometer of 24,000 coils, by far the most sensitive ever made up to that time, and by its means succeeded in disclosing an electrical phenomenon in the tetanized nerve, which, for certain reasons we cannot here explain, he styled the negative variation of the nerve-current. In point of fact, he transmuted into a deflection of the galvanometer that molecular change in the nerve which, had it reached the muscles, would have convulsed them, and which, had it reached the brain, would have caused pain. He also decided the long-vexed question whether the nervous fibres conduct only in one direction, or in both, by showing that the negative variation is equally well transmitted in a motor nerve in the centripetal, and in a sensitive nerve in the centrifugal direction.

Soon after the publication of his "Researches," Du Bois-Reymond, then thirty years old, was elected a member of the Royal Academy of Sciences of Berlin. As already stated, he has ever since pursued and extended his investigations; but it is impossible, in the compass of this brief notice, more fully to detail their results. Moreover, those of our readers who may feel interested in the subject will find a conscientious exposé of most of Du Bois-Reymond's papers in the book of one of our countrymen, of whose talents science has been robbed by a premature death—Mr. Charles E. Morgan, author of "Electro-Physiology and Therapeutics" (New York, William Wood & Co., 1868). These results will also be found in Prof. Rosenthal's German treatise on the "Physiology of Muscles and Nerves," contributed to the "International Scientific Series," and soon to be published in this country. Du Bois-Reymond's papers have also been collected in two volumes, under the title "Gesammelte Abhandlungen zur allgemeinen Muskel-und Nervenphysik" (Leipsic, Veit & Co., 1875-'77).

Several of Du Bois-Reymond's papers bear merely upon electricity, without reference to physiology. We will only mention his experimental and theoretical researches on the aperiodic state of the magnetic needle induced, under certain circumstances, by high dampening powers; these researches are of the greatest practical importance. Du Bois-Reymond also showed, contrary to what Berzelius and Liebig had stated, that the substance of muscles when at rest is neutral, or slightly alkaline, becoming acid only after death, when rigor mortis sets in, but that also in the act of contraction acid is evolved.

In 1858 John Müller died, and Du Bois-Reymond was appointed in his place Professor of Physiology in ordinary, and Director of the Physiological Laboratory at the University of Berlin. In this position he has exercised a considerable influence on the progress of physiological study in Germany. Many of the professors of physiology at the other German universities have been his pupils; and this influence has been increased by the friendship which has always connected him closely with his fellow-students Brucke, Helmholtz, and Ludwig—all of them physiologists as averse as he to the doctrine of vital forces, and as eager to reduce physiology to applied chemistry, natural philosophy, and mathematics. He was also one of the founders of the Physical Society of Berlin, whose reports on the progress of natural philosophy are well known to every lover of science.

In 1867 Du Bois-Reymond was elected one of the secretaries of the Academy of Sciences of Berlin, and this office afforded him the opportunity of displaying, in the public addresses which it imposes on him to deliver, a new side of his genius. He generally chooses some subject in the history of science on which he knows how to throw a new and brilliant light, as in his essays on Voltaire and on Lamettrie, which have not yet appeared in English.

Du Bois-Reymond is considered one of the most successful teachers of the university, and the public lectures, in which he yearly alternates between "Anthropology" and "Some Recent Advances in Physical Science," are often dangerously crowded. Having been a good deal in England, and married a lady of English education, he commands the English language sufficiently to lecture in it. The late Dr. Bence Jones, of London, who had formed an intimate friendship with Du Bois-Reymond, and had published an abstract of his discoveries ("On Animal Electricity," etc., London, Churchill, 1852), engaged him repeatedly to lecture in the Royal Institution, where Dr. Faraday, and other eminent Englishmen of science, were much interested in his experiments. In 1855, in the theatre of the Royal Institution, he showed, and described in the Philosophical Magazine, the beautiful method of rendering the deflection of a galvanometer visible by a beam of light reflected from a mirror attached to the needle; of which method Sir William Thomson subsequently availed himself for the readings of the Atlantic Telegraph so successfully that it has ever since been attributed to that able physicist.

Du Bois-Reymond is a member of the Academies of Vienna, Munich, and Rome, and an associate of the Royal Societies of London, Göttingen, Upsala, etc. He has been employed these last three or four years in erecting in Berlin, at the expense of the German Government, the largest and finest physiological laboratory in existence. His new lecture-room is said to be the most beautiful and best appointed in the world.