KÜhne, Wilhelm Friedrich

(b. Hamburg, Germany, 28 March 1837; d Heidelberg, Germany 10 June 1900)

physiology, physiological chemistry.

Willy Kühne was the fifth of seven childre. His father was a wealthy Hamburg merchant; his mother was interested int he arts and politics. He attended grammar school at Lüneburg, but preferred his own scientific experiments to the Latin grammar. In 1854, at the age of seventeen, he entered the University of Göttingen, where he studied chemistry under Wöhler, anatomy under Henle and neurohistology under Rudolf Wagner. Two years later he obtained the Ph.D. with a thesis on induced diabetes in frogs. He then spent some the time at the University of Jena, where he worked with Carl Gustav Lehamann on diabetes and sugar metaboilsm.

In 1858 Kühne worked in Berlin with E. du BoisReymond on problems of myodynamics and with Felix Hoppe-Seyler, who was in charge of the chemical laboratory at the institute of pathology directed by Rudolf Virchow. His other associates there included Julius Cohnheim, W. Preyer, F. C. Boll, Hugo Kronecher, and Theodor Leber. In the same year Bernard’s report on Suger puncture prompted Kühne to go to Paris, where he recived many suggestions regrding scientific methods. In 1860 he spent some time in Vienna working with Ernst Brücke and Carl Ludwig. Most Probably it was Brucke who imparted to him his interest in the physiology of the protozoa and the nature of protoplasm. In 1861 he began his independent scientific career, succeeding Hoppe-Seyler as assistant in the chemical department of virchow’s institute. The latter gave him a completely free hand with the his work. At the institute Kuhne did not investigate strictly patholgical question but dealt with cytophysiological problems. In 1862, at the instigation of Albert von Bezold, Kuhne was awarderd in an honorary M. D. by the University of Jena. During the Seven Week’s War between Prussia and Austria in 1866 he was given charge of epidemic control. He left Berlin in 1868 to take over the chair of physiology at Amsterdam; Gustav schwalbe and, later, Thomas Lauder-Brunton became his collaborators.

In 1871 Kühen succeeded Helmholtz in the chair of physiology at Heidelberg; his collegues included E. Salkowski, J. N. Langley, and R. H. Chittenden. HE married Helene Blum, the daughter of a Heidelberg mineralogiost, and continued to teach and do research there until and the his retirement in 1899. In 1875, on his initiative, a new building for the institute of Physiology was built. On the twenty-fifth anniversary of kuhne’s appointment at Heidelberg (1896) a jubilee volume of the Zeitschrift fur Biologie was published with contri butions by E. Salkowski, J. von Uexkull, G Suhwalbe, of great versatility, Kuhne was found of good company and associated with artists as well as scientists. He died at the age of sixty-three of the sequelae fo pneumonia.

Kühen’s most oustanding gift was his ability to select significant problems, which the he approached inventively, using a wide variety of technical devices. He substantially advanced research in the physiology of metabolism and digestion (sugar, protein, bile acids, trypsin), the physiology of muscle and nerves, the physiology of protozoa and physiological optics. Many of his results and observation of were immediately integrated into standard texts.

After presenting his doctoral thesis on induced diabetes in frogs, in 1856 Kühen elaborated a problem previously dealt with by Wohler, who had stated that the benzoic acid ingested in food is found in the urine in the form of hiuric acid. Kühne proved that this compound is produced in the liver (although the same may also produce succinic acid, at least in carnivorous animals).

While collaborating with du Bois-Reymond in Berlin, Kühne began to study problems of myodynamics, simultaneously applying physiological, microscopical, and chemical methods to arrive at some essentially novel findings. He investigated histologically the nature of the motor nerve endings (1868) and found their terminal organs, which exist as motor end plates in warm-blooded animals. In preparations of the sartorius, a muscle rarely used until then for experimental purposes, he established the two-way conductibility of the muscle fiber (1859) and the direct excitability of the muscle fiber by both electric and chemical stimuli.

From the sartorius Kühne obtained coagulable myosin; assuming the heat rigor of the muscle to be a clotting process, accompanied by a clouding of the muscle substance, he was led to believe that the living muscle must be viscous in consistency. He later fortuitously proved this assumption when he observed a nematode creeping forward in a living muscle fiber (1863). Kühne also ascertained that the myohematin myoglobin is related to hemoglobin and, having suspected that contractile elements were involved in the creeping motions of the amoebas, proved the electric excitability of monocellular organisms (1864). Through his research, Kühne demonstrated the extraordinary usefulness of cytophysiological investigations for the solution of problems of general physiological.

Beginning with his stay at Amsterdam, Kühne again turned to problems of physiological chemistry, especially those of digestion. In particular he carried out investigations on the splitting of the large protein molecule during digestive fermentation. Since the stomach is not digested by its own pepsin, he concluded that such ferments have inactive protein precursors, which he called “zymogens”; he then traced the disintegration of proteins into albumoses and peptones. He further succeeded in demonstrating microscopic changes in living pancreatic cells during their activity. Having learned the technique of pancreatic fistula from Claude Bernard in Paris, Kühne pursued the study of the proteolytic effect of the pancreatic enzyme, which he called trypsin (1877).

Kühne’s hehrbuch der physiologischen Chemie appeared in 1868. It clearly and concisely presented the state of the science at that time. In 1877 Kühne took up a completely different topic. In 1876 Boll had established that the layer of rods of the retina contain a purple pigment that disappears on exposure to light. On this basis Kühne supposed that there was a primarily chemical process that preceded excitation of the optic nerves; he demonstrated that the retina works like a photographic plate, with light bleaching out the visual purple, which is regenerated in darkness. He succeeded in producing his famous “optograms”—the reproduction of the pattern of crossbars of a window on the chemical substance on the retina of a rabbit (1877–1878). Kühne was thus the first to perceive the migrating pigments in the living retina. His assumption that a photochemical process occurs prior to the excitation of the retina led him to investigate the electric processes in the eye, thus linking his research with the work of du Bois-Reymond and Holmgren. It may be noted that Kühne’s research, as was typical of the work of German physiologists of the second half of the nineteenth century, always began with the formulation of a question rather than growing from a method.

Shortly before his death Kühne published a remarkble lecture on the responsibility of the physician to his patient and the relationship of medicine to science (1899). He postulated medical ethics as a subject in medical training and he believed that both a sympathetic heart and a clear, keen mind were necessary qualities for a physician. He regarded the concept of the immortality of the soul as important to the attitude of the physician and anticipated an era in which medical science would have to adapt more to the needs of society than it had done until then.

BIBLIOGRAPHY

I. Original Works. Kühne’s monographs include Myologische Untersuchungen (Leipzig, 1860); Über die peripherischen Endorgane der motorischen Nerven (Leipzig, 1862); Untersuchungen über das Protoplasma und die Contractilität (Leipzig, 1864); Lehrbuch der physiologischen Chemie, I, 3 pts. (Leipzig, 1866–1868); Untersuchungen aus dem Physiologischen Institut der Universität Heidelbert, 4 vols. (Heidelberg, 1878–1881); and Über Ethik und Naturwissenschaft in der Medizin. Ein Auszug aus der Geschichte der Medizin (Brunswick, 1899).

His articles include “Über künstlich erzeugten Diabetes bei Fröschen,” in Nachrichten von der Königlichen Gesellschaft der Wissenchaften und der Georg Augusta-Universität zu Göttingen (1856), 217–219; “Über die Bildung der Hippursäure aus Bensolsäure bei fleischefressenden Thieren,” in Virchows Archiv für pathologische Anatomie und Physiologie, 12 (1857), 386–396, written then W. hallwachs; “Zur Metamorphose der Bernsteinsäure,” ibid., 396–401; “Beiträge zur Lehre vom Icterus. Eine physiologisch-chemische Untersuchung,” ibid., 14 (1858), 310–356; “Über die selbständige Reizbarkeit der Muskelfaser,” in Montsberichte K. Preussischen Akademie der Wiseenschaften zu Berlin (1859), 226–229; “Die Endigungswesie der Nerven in den Muskeln und das doppelsinnige Leitungsvermögen der motorochen Nervenfaser,” ibid., 395–402; “Sur l’irritation chimique des nerfs et des mucles,” in comptes rendus hebdomadaires des séances de l’Académile des sciences, 48 (1859), 406–409, 476–478l and; “Recherches sur les propétés physologiques des muscles,” in Annuals des sciences naturelles, 14 (1860), 113–116.

Subsequent works are “Eine lebebde Nematiode in einer lebendent Muselfaser beobachtet,” in Virchows Archive, 26 (1863), 222–224; “Über den dies Verdauung der Eiweissstoffe durch de Pankreassaft,” ibid., (1867), 130–172;” Über das Trypsin (Enzym Des Pankreas),” in Verhandlungen des naturahistorisch—medizinischen Verieins zu Heidelberg1 (1877), 194–198; “Zur photochemie der Netzhaut,” ibid., 484–492’ “Über den Sehpurpur,” in Untersuchungen aus sem physiologischen Institut der Universitäat Heidelberg, 1 (18578), 15–103 “Ü die nächesten Spaltungsprodukete der Wiweisskörper,” in Zeitschrift für Biologie19 (1883), 159–208, written with R. H. Chittendenuy “Über elektrische Vorgäange im Sechorgan,” in Verhandlungen des naturhistoriusch—medizinschen Vereinx zu Heidelberg3 (1886), 1–9, written with J. Steiner; “Über die Peptone,” in Zeitschrift für Biologies, 22 (1886), 423–458; and “zur Darstellung des Sechpurpus,” ibid., 32 (1895), 21–28.

II. Secondary Literature. There is no complete bibiliography. Compilations are to be found in the IndexCatalogue of the Library of the Surgeon—General’s Office, U.S. ARmuy, 1st ser., VII (Washington, 1886), 569; 2nd ser, VIII (Washington, 1903), 827–873, See aslo the Royal Society Catalogue of Scientific papers III, 768–769; VIII 133; X, 472–473; XII, 417 XVI, 495–496.

Obtituaries are by F. Hofmeister in Berichte der Deutschen chemischen Gesellschaft, 33 (1900), 3875–3880; Alois Kreidel, in Wiener klinishce Wochenscrift, 13 (1900), 648–950; Franz Müller, in Deutsche medizinsche Wochenschrift26 (1900), 440–441; Paul Schultz, in Berliner Klinische Wopchenscrift37 (1900), 606–608; J Von Uexküll, in Münchener medizinische Wochenschrift47 (1900), 937–939; Carl Voit, in Zeitschrift für Biologie, 40 (1900), i–viii.

See also Haberling, et al., eds., Biographisches Lexikion der hervorragenden Ärzte aller Zeiten und Völker, 2nd ed., III (Berlin—Vienna, 1931), 627; Hugo Kronecker, “Ein eigenartiger deutscher Naturforcher. Zum Andenken an Wily Kühne,” in Deutshce Reveu, 32 (1907), 99–112; and Theodor Leber, “Will Kühne,” in Heidelberger Professoren aus dem 19. Jahrhunmdert, II (Heidelberg, 1903), 207–220.

K. E. Rothschuh