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Brücke, Ernst Wilhelm von

Brücke, Ernst Wilhelm von

(b Berlin, Germany, 6 September 1819; d. Vienna, Austria, 7 January 1892)


Brücke was the son of a painter and thought of following his father’s profession. Even though he became a doctor instead, he dealt throughout his life so intensively with questions concerning the theory of art that they form an integral part of his work.

In 1838 Brücke began studying at Berlin. His final teacher, whose assistant Brücke became in 1843, was the physiologist Johannes Müller, whose circle of friends and colleagues at that time included Hermann von Helmholtz, Emil Du Bois-Reymond, and, indirectly, Carl Ludwig. Brücke formed lifelong friendships with all these men. In 1842, on the basis of his dissertation De diffusione humorum per septa mortua et viva, he was graduated as a doctor of medicine and surgery. In this dissertation he tried to prove that the phenomena of osmosis are not to be related to any sort of uncertain vital force, but to weighable and measurable, repelling and attracting physiochemical forces; what he sought to prove was a part of the program of the new physical physiology. Du Bois-Reymond formulated it in the following way: “Brücke and I, we have sworn to each other to validate the basic truth that in an organism no other forces have any effect than the common physiochemical ones….”

For this program the eye was an especially suitable subject for investigation. Brücke examined optical media, afterimages, stereoscopic vision, and the reflection of light from the backgrounds of the eyes of vertebrates; he also discovered the ciliary muscle named after him. His Anatomical Description of the Human Eye (1847) has become the standard anatomical-histological work for contemporary oculists.

His research on luminescence in animal eyes and his method of causing luminescence at will in the human eye created the foundation on which Helmholtz continued his work and which led to the invention of the ophthalmoscope in 1851 by the latter. How close Brücke himself had come to this discovery was later attested by Helmholtz: “He had merely neglected to ask himself to which optical image the rays reflected from the luminescent eye belonged.”

In 1848 Brücke became professor of physiology at the University of Königsberg. The following year, he went in the same capacity to Vienna, where he founded a school for physiologists that eventually extended far beyond the borders of Austria and there worked until his death. Brücke’s laboratory trained the Austrian physiologists S. Exner, A. Rollett, E. von Fleischl-Marxow, M. von Vintschgau, and A. Kreidl; the German W. Kühne; the Swede F. Holmgren; the Englishman T. Lauder-Brunton; and the Russians Elie Cyon, N. von Kowalewsky, and I. M. Setchenoff. Freud, who worked there from 1876 to 1882, considered Brücke the most highly respected teacher and the greatest authority in the field he had ever met.

Here, in the major city of a polyglot country, Brücke had an unusual opportunity to study linguistic and vocal physiology. To determine each sound of an arbitrary language in his own (alphabetical) characters and thereby to give a phonetic transcription was the aim of his Characteristics of the Physiology and Taxonomy of Linguistic Sounds (1856). With the aid of a labiograph he made the first attempt to measure exactly the length of strongly and weakly accented syllables in verse. He recorded the results of these measurements in a monograph, The Physiological Bases of New High German Poetic Art (1871). There is unmistakably evident here a typical endeavor of the times (primarily to analyze the effect of a work of art rationally, i.e., by means of scientific methods), as is also the case in Brücke’s writings concerning the theory of art, which deal with the determination of the classical ideal of beauty. Such analysis was alien to Billroth’s intuitively synthetic comprehension of art: “It is as if one wanted to describe how a good apple tastes; one has to eat it himself; if he does not then recognize it, he should stay with potatoes.”

It is said that Brücke was one of the most versatile physiologists of his day. His Lectures On Physiology (1873–1874) confirms this; in it he added something of his own to almost every chapter. The diversity of his interests made limited specialization alien to Brücke. His investigations included the physiology of digestion; from 1850, Brücke studied the digestive tract microscopically and recognized the structures designated as Peyer’s “glands” as the places where the lymphocytes develop. He explained the mechanism of the transfer of chyle by means of the contraction of intestinal villi. In his work on chyle, which was published for the most part in the Proceedings of the Imperial Academy of Sciences in Vienna, he encountered an abundance of questions concerning the reabsorption of fats, carbohydrates, and proteins. As a result, he developed many biochemical concepts. Brücke introduced the terms “achroödextrin” and “erythrodextrin” into physiological chemistry; he discovered that blood did not coagulate in uninjured vessels, and he became a pioneer in enzyme research through his experiments on peptic digestion. With these experiments he endeavored to produce the purest possible pepsin solutions. He tried to combine pepsin mechanically with small solid bodies such as calcium phosphate, sulfur, and cholesterol, and subsequently to extract it again from its adsorbates. He succeeded herein along two possible avenues of approach (through precipitation of calcium phosphate with water, or by treating the cholesterol precipitation with ether). But in order to reach his goal he needed control reactions for further purification, which he did not have.

Brücke is generally honored as a microscopist without it being pointed out that his microscopic investigations invariably grew out of his physiological inquiries and were determined by them. The investigation of function was his chief aim when he observed the flow of protoplasm in the stinging hairs of nettles or molecular motion in the salivary particles or—a classic example of the synthesis of histological, physical, and experimental methods—when he explained the changing of a chameleon’s colors by the momentary shifting movements of the skin’s pigment cells. Such diverse studies on the function of the most varied cells led Brücke to criticize the mechanistic ideas of structure in the cell theory of Matthias Schleiden and Theodor Schwann—of the cell as a shell formed by the cell membrane. While he and Max Schultze, a histologist from Bonn, were beginning to distinguish protoplasm as an essential cellular component, he was at the same time paving the way for a biological theory of cells in his investigation entitled The Elementary Organisms. In 1867–1868, with his experiments on the possibility of electric stimulation of muscles, Brücke moved into the specialty of his friend Du Bois-Reymond, i.e., general nerve and muscle physiology. Du Bois-Reymond held that the stimulating effect of an electric current depended solely on how fast such a current was increased in the stimulated organ and not on how long the stimulus lasted. Brücke, on the other hand, observed that in curare-treated frog muscles a current that was increased too slowly remained ineffective. Accordingly, in electric stimulation the time factor had to be considered no less than the amount of current. In regarding the stimulus as a function of the “distance from the normal state,” Brücke arrived at a new concept of the law on stimulation, which approximates modern concepts more closely than the first formulation by Du Bois-Reymond.

When Brücke resigned his teaching position in 1890, he had 143 publications to his credit. The range of this output is made evident by the number of different areas of work: physics, plant physiology, microscopic anatomy, physiological chemistry, physiological optics, and purely experimental physiology. He received many honors from numerous academies, including the highest Prussian order, the Order of Merit, and Austrian ennoblement. Such acclaim left untouched the genuine inner modesty of this great researcher, who was interested only in examining the events of nature with a view to their objective regularities.


I. Original Works. Note references in text. A complete list of works is in E. Th. Brücke, Ernst Brücke (Vienna, 1928). The most important works and the most important secondary literature are in E. Lesky, “Die Wiener medizinische Schule im 19. Jahrhundert,” in Studien zur Geschichte der Universität Wien, VI (Graz-Cologne, 1965), 258 ff.

II. Secondary Literature. See S. Exner, “Ernst von Brücke und die moderne Physiologie,” in Wiener klinische Wochenschrift, 3 (1890), 807–812; obituary by A. Kreidl, ibid., 5 (1892), 21 f. See also E. Suess, in Almanach der Akademie der Wissenschaften in Wien, 42 (1892), 184–189; and E. Brücke, “Ernst Wilhelm Brücke,” in Neue Österreichische Biographie, V (1928), 66–73.

Erna Lesky

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Brücke, Ernst Wilhelm von (1819-1892)


A German doctor and physiologist, Ernst Wilhelm von Brücke was born June 6, 1819, and died January 7, 1892, in Vienna. The son of a portrait and historical painter, following his mother's premature death he was raised by his uncle, the superintendent C. Droysen, in Stralsund. He studied medicine in Berlin and Heidelberg in 1838 and became a doctor of medicine in Berlin in 1842. In 1843 he became an assistant to Johannes Müller at the Museum of Comparative Anatomy and a prosector; in 1846 he also served as a teacher of anatomy at the Academy of Fine Arts in Berlin.

Brücke completed his degree in physiology in 1844 and was appointed full professor of physiology and general pathology in Königsberg, and professor of physiology and (microscopic) anatomy in Vienna, where he held the chair of physiology for forty years, until his appointment as professor emeritus in 1890. He was ennobled in 1873 and became rector of the University of Vienna in 1879. He was a member of the Academy of Sciences, the Prussian Order of Merit, and the Upper House of Austria, and received numerous decorations and honorary distinctions. As a co-founder of the Physics Society in 1845 (the Berlin and later the German Physics Societies were offshoots of this organization), he was, along with Emil Du Bois-Reymond, Hermann von Helmholtz, and Karl Ludwig, one of the defenders of organic physics, which, in contrast to the then-dominant vitalist tradition, held that all vital manifestations were the result of physico-chemical forces in the organism.

Brücke was the most learned physiologist of his time and helped enrich several areas of natural science. He was active in the physiology of optics, the physiology of plants, the physiology of digestion, of the blood, the nerves, and the muscles, cellular physiology, biochemistry (the purification of pepsins, which led to our understanding of enzymes), the physiology of speech, and even linguistics. His many publications included the two-volume Vorlesungen über Physiologie (Lessons on Physiology; 1873, 1874). Brücke's laboratory was a place where fundamental research on the exact sciences of nature was carried out and he introduced a new methodology to the Vienna school of medicine, which was strongly influenced by his work.

Sigmund Freud, who described Brücke as the "highest authority who has ever had an influence on me," worked in Brücke's laboratory between 1876 and 1882. His earliest writings on neurophysiology are based on his work there and Brücke's influence is clearly evident in Freud's earliest theoretical writings on psychoanalysis. Brücke, who had sponsored Freud for a professorship, referred, in his letter of recommendation, to Freud's work on neurology as being "very important." He also helped Freud obtain the travel stipend that allowed him to work with Charcot in Paris.

Helmut GrÖger

See also: "Autobiographical Study, An"; Freud, Ernst; German romanticism and psychoanalysis; Interpretation of Dreams, The ; Reversal into the opposite; Science and psychoanalysis; Vienna General Hospital.


Bernfeld, Siegfried. (1949). Freud's scientific beginnings. American Imago, 6, 163-196.

Brücke, Ernst Wilhelm von. (1873-1874). Vorlesungen über Physiologie. Vienna: Wilhelm Braumüller.

Jones, Ernest. (1953). Sigmund Freud: Life and work. London: Hogarth Press.

Lesky, Erna. (1965). Die Wiener medizinische schule. 19 Jahrhundert. Graz-Köln: Hermann Böhlaus.

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