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Abderhalden, Emil


(b. Oberuzwil [canton St. Gallen], Switzerland, 9 March 1877; d. Zürich, Switzerland, 5 August 1950),

physiology, biochemistry, medical ethics.

Abderhalden was a leading figure in the early development of modern biochemistry. He made important contributions to protein chemistry, in particular to the clarification of the composition of peptides, and to nutritional research. The detection of what he believed were specific proteases (Abwehrfermente, defense enzymes) proved a mistake, however. He was a controversial protagonist in matters of medical ethics and eugenics and involved himself in social and political affairs to an extraordinary degree. He was the president of the oldest German academy, the German Academy of Natural Scientists Leopoldina (now German Academy of Sciences Leopoldina), during the years of the National Socialist (NS) regime.

Abderhalden, son of the primary school teacher Nikolaus (also known as Niklaus) Abderhalden and his wife Anna Barbara (née Stamm), studied medicine in Basel (medical examination in 1901, doctor’s degree in 1902). Already as a student, Abderhalden was mentored by the professor for physiological chemistry, Gustav von Bunge. Abderhalden also followed Bunge’s example of active engagement in social matters and in his fight against the abuse of alcohol.

While studying issues of digestion and the resorption of iron, Abderhalden began to study the composition of proteins. To continue his studies, he went to Berlin. Here he worked in the laboratory of the famous chemist Emil Hermann Fischer. In Fischer’s laboratory, Abderhalden was introduced to his future principal field of work, protein biochemistry, and started his career (1904 habilitation in physiology, 1908 title professor). In 1908 he succeeded the sensory physiologist Hermann Munk as ordinary professor for physiology at the Berlin Veterinary College. After he had refused to go to Tübingen, he accepted the appointment as ordinary professor for physiology at Halle University (succeeding Julius Bernstein) in 1911.

Initially, Abderhalden regarded Halle as a waiting place. The Kaiser Wilhelm Society (Kaiser Wilhelm Gesellschaft, or KWG) had earlier promised him a new research institute in Berlin or Cologne. The plans, at first postponed because of World War I and the difficult postwar years, never materialized, although Abderhalden did occasionally receive financial support for his research work from the KWG. Despite attractive offers, for example from the universities of Vienna and Basel, and various lamentations about his outdated institute (since he initially did not promote a planned new university institute because of the KWG prospect, and later the opportunity disappeared for lack of money and then the beginning of World War II), Abderhalden remained in Halle until 1945. There he could teach both physiology and physiological chemistry, whereas the other institutions generally offered him teaching possibilities for only one discipline. The expansion of biochemistry, which Abderhalden also promoted, tended more and more toward a total (also organizational) separation of biochemistry from physiology. Abderhalden also remained in Halle in order to manage several social activities set up according to his ideas. This engagement meant a lot to him, and he dedicated to it much time and effort—quite uncommon for the work of an experimenting academic teacher.

Research Under the supervision of his teacher Bunge, Abderhalden began his research activities doing comparative analytical work on blood and milk from different species. Knowing the differences between food proteins and functional proteins in the body, Abderhalden was convinced that the current understanding of digestion was wrong. Many physiologists, including Bunge, believed that proteins taken in with food would only be disintegrated during digestion for exploitation in the body but largely remain structurally unchanged or be decomposed only to a small extent so that less energy should be required to build endogenous proteins. Abderhalden argued that during digestion in the intestines, food proteins are disintegrated as far as into the free amino acids, which are then resorbed and transported by the blood. In Fischer’s laboratory, he worked on the degradation of proteins and the synthesis of short-chain “polypeptides” and contributed to the understanding of the structure of peptides (or proteins as understood at that time; since the macromolecular structure was discovered later, this “understanding of proteins” could only be fragmentary). Later Abderhalden showed that, in nutrition, proteins can be represented by free amino acids; developed solutions for a substitution therapy (also in connection with industry); and looked at the different biological value of amino acids, as some had to be taken in with food whereas others were synthesized by the body. He also dealt with issues of hormone and vitamin research. He also discovered a cystine storage disease, Abderhalden-Fanconi (-Kauf-mann-Lignac) syndrome.

In his research, Abderhalden always attempted to derive practical benefit for medical therapy. His Abwehrfermente gained Abderhalden scientific fame for a short while. (These were first called Schutzfermente, or protective ferments, in the original edition of Schutzfermente des tierischen Organismus [1912].) He developed and constantly improved the so-called Abderhalden Reaction (AR), a complicated method for verifying the assumedly highly specific defensive ferments against “foreign” proteins. The concept of defensive ferments, simply stated, meant that any “foreign” proteins (e.g., foreign to blood, like cancer cells, or exogenous, like parts of bacteria) that go into blood should prompt specific ferments (enzymes) that did not occur there previously and that now decompose these “foreign” substances. These defensive ferments were thought to be verifiable in blood through reaction with certain substrates (obtained from substances either foreign to blood or exogenous) by means of two processes, namely the optical method and the dialysis method. Abderhalden developed a multitude of possible applications—from the detection of pregnancy to tumor diagnosis. The AR was supposed to be a useful diagnostic tool for dysfunctions of internal organs, several infectious diseases, and even psychiatric states.

Initially, Abderhalden’s methods met with wide interest in medical circles, but the concept as a whole failed to stand the acid test of science. The ongoing controversies damaged Abderhalden’s reputation as scientist; but despite a multitude of counterarguments from well-known researchers, he insisted on his misconceptions. Despite a loss of public interest in the subject matter in the 1920s, Abderhalden’s methods had a renaissance during the Third Reich. It has been proved that Abderhalden’s methods were used by coworkers of some National Socialist researchers (for example, Otmar Freiherr von Verschuer and Claus Schilling) who were charged with Nazi crimes.

The complexity of the method, with its failure-prone steps (for example, substrate preparation) and difficulties in handling, and vulnerable statements or mistakes in the arguments of his opponents often allowed Abderhalden to reject falsifications. He always tried to invalidate objections by putative improvements of his method, but he failed to take the important step from a qualitative (coloration) evaluation to a quantitative (exact measured) one (even though he himself regarded measurement as necessary). Furthermore, he tested new (clinical) applications in several very different fields with questionable results instead of elucidating the fundamentals of his putative discovery by basic research.

During World War II, Abderhalden was prevented by a heavy workload of applied research from adapting his methods to the up-to-date standards of biochemistry. He also lacked opportunities for international comparison. After World War II, he had hardly any opportunity to work experimentally at his last place of activity in Zürich. Therefore he was able to adhere to his incorrect principles. Thus his defense enzymes are now mentioned in connection with scientific errors, occasionally even fraud, in the natural sciences. Although it has to be kept in mind that neither immunology nor enzymology in a modern sense existed when Abderhalden conducted his experiments, the question as to the causes of his persistence in error while confronting strong contemporary evidence is largely unsolved. The complexity of the experiments certainly played an important role. Unquestionably, Abderhalden contradicted his own standards in neglecting the need for quantitative measurements and in his emphasis on applications instead of fundamental research. Nevertheless, Abderhalden’s;s importance should not be limited to the Abwehrfermente question.

Abderhalden was a gifted and strict university teacher with a large circle of students (for example, Hans Brock-mann, Horst Hanson, Kurt Heyns). He authored sought-after textbooks on physiological chemistry and physiology and edited multivolume method manuals. From the early1930s he came into conflict with the emerging National Socialists at the university; they defamed his institute as an“El Dorado of Jews and aliens” (“Der Kampf,” No. 136, p. 9, Thu 18.8.1932). Indeed, Abderhalden had a number of students, among them Andor Fodor, Ernst Gellhorn, and Ernst Wertheimer, who were deemed “Jews” in National Socialist terminology and had already left Germany during the Weimar Republic or were expelled from Germany after 1933. On the one hand, Abderhalden, who was known as a democrat at the University of Halle, was the focus of attention of some Nazi students who demanded his dismissal and opposed the international orientation of his Leopoldina management. On the other hand, Abderhalden welcomed important parts of National Socialist policy, especially the image of physicians as “guardians” of national health, and the eugenic actions, including the sterilization law. Throughout his life, Abderhalden regarded social questions in the light of his eugenic convictions.

Since Abderhalden was a Swiss as well as a German national, he was not conscripted to the German armed forces in World War I. So he organized the transport of the wounded in Halle and equipped several mobile army hospitals with money donated by citizens. In 1915 he founded an alliance for the preservation and augmentation of German national power; one of its activities was to ensure the supply of food to the people of Halle by leasing land for growing potatoes. Abderhalden set up an infant nursery, and after the war he organized holidays in Switzerland for more than sixty thousand weak German children.

In his book Das Recht auf Gesundheit(1921), Abderhalden detailed his eugenic opinion and advocated the sterilization of persons with genetic diseases. In the 1920s, he tried to set up a physicians’ and popular alliance for sexual ethics and founded a journal (Ethik) that dealt with matters of ethics (for example, experiments involving humans, eugenics) and controversially discussed questions of medical ethics. Ethik—although later sympathetic to the National Socialist zeitgeist—sometimes harbored views in contradiction to the official NS line. Ethik demanded very outspoken “positive eugenics” and emphasized that sterilization of people suffering from a hereditary disease was by no means sufficient, but should be complemented by advancement of families, provision of universal healthy housing, and the fight against alcohol. Also, the euthanasia of incurably ill people was already discussed and rejected in the mid-1930s, at a time when the NS leadership explicitly refused to have this issue on the agenda. These discussions were held before the NS instituted its euthanasia program and were not conducted in the same spirit. The journal ceased publication after serious controversies in 1938 without, however, having been banned.

Abderhalden’s ethical maxims always valued the people (Volk) over the individual. Here there is a clear link to the National Socialist “ethic without humanity.” As a social ethicist, Abderhalden viewed himself as a “physician” for the “Volkskörper” (body of the people). According to his ethical views, individual rights had to be curtailed if it seemed necessary for the “advancement of the Volk.” Important elements of his ethics, such as eugenic convictions, related to the advancement of future generations.

Abderhalden’s ethical and eugenic concepts must be considered in their historical context. Abderhalden formed his ethical and eugenic views in the crisis years after World War I. He not only established theoretical principles, he also rendered practical help to cope with a major crisis. He rescued many German children from hunger and tuberculosis by accommodating them in Switzerland. This cannot be explained without reference to his strong eugenic convictions. Abderhalden absolutely shared the opinions voiced by many eugenists at that time: While the best men had fallen at the fronts and were unavailable to manage economic recovery, many handicapped who, had been unfit for military service, had survived in institutions and now had to be supported by an impoverished state. Abderhalden demanded that the scarce funds should not be spent on those people suffering from hereditary diseases because they were of “less value” for the continued existence of the nation, but should be concentrated to ill children (who could be cured with “reasonable” spending of funds) as guarantors of future generations and thus a successful future.

But Abderhalden’s point of view is by no means identical with the National Socialist ethic. It would be incorrect and unhistorical to regard Abderhalden’s convictions as convenient justification for the Nazi crimes. However, the fact of a serious and far-reaching entanglement, for example, his approval of the Nazi sterilization law, has to be recognized.

Abderhalden had been a member of the German Academy of Natural Scientists Leopoldina (Leopoldina) since 1912 and chairman of the medical section from 1926 to 1931. In 1931, he was elected president of this oldest German academy, founded as the Academia Naturae Curiosorum in 1652. When he assumed office in 1932, he supported the membership of many well-known foreign scientists, reorganized the academy’s structures, and expanded its range of activities. While advocating high scientific standards, Abderhalden was also ready to make concessions to the National Socialist state policy and the “NS-Zeitgeist.” Abderhalden prevented the election to the academy of National Socialist exponents whose scientific achievements he considered as being insufficient and he refused to accept foreigners proposed for political reasons. But under his leadership nearly all important champions of race hygiene were listed in the academy register, and he celebrated the so-called achievements of the Führer (Adolf Hitler) at the annual festive academy sessions. The most serious breach of academic integrity was the cancellation of membership of many Jewish academy members (among them Albert Einstein), mainly in the years 1937–1938. Abderhalden reported the cancellation to the local National Socialist authority, the Gauleiter, but he did not inform either the members whose membership had been canceled or the public.

After World War II, on the order of the American occupation forces, Abderhalden was deported on 24 June 1945 from Halle, later to be a part of the Soviet-occupied zone, to a place near Darmstadt in the American zone. Abderhalden was the head of a trek of about 750 people (the “Abderhalden-Transport”). In September 1945 Abderhalden returned to Switzerland. He worked as a professor of physiological chemistry at the University of Zürich before he finally retired in 1947. With his book Gedanken eines Biologen(1947), Abderhalden reviewed his life convictions without, however, admitting to his association with the National Socialist regime. Although living in Zürich, Abderhalden remained president of the Leopoldina until his death; the difficult daily business in the Soviet-occupied zone/German Democratic Republic was managed by his deputy, the geographer Otto Schlüter, in Halle. Abderhalden was married to Margarete Barth; they had five children.



Editor. Bibliographie der gesamten wissenschaftlichen Literatur über den Alkohol und den Alkoholismus. Berlin and Vienna: Urban & Schwarzenberg, 1904.

Lehrbuch der physiologischen Chemie in dreissig Vorlesungen. Berlin and Vienna: Urban & Schwarzenberg 1906.

Editor. Biochemisches Handlexikon. 14 vols. Berlin: Springer, 1911–1933.

Schutzfermente des tierischen Organismus: Ein Beitrag zur Kenntnis der Abwehrmabregeln des tierischen Organismus gegen körper-, blut- und zellfremde Stoffe. Berlin: Springer, 1912.

Editor. Handbuch der biologischen Arbeitsmethoden. 106 vols. and register volume. Berlin and Vienna: Urban & Schwarzenberg, 1920–1939.

Das Recht auf Gesundheit und die Pflicht, sie zu erhalten: Die Grundbedingungen für das Wohlergehen von Person, Volk, Staat und der gesamten Nationen. Leipzig, Germany: Hirzel, 1921.

Editor. Ethik, Pädagogik und Hygiene des Geschlechtslebens (1922), later:Sexualethik (1925),Ethik: Sexual- und GesellschaftsEthik (1926–1933),Ethik (1933–1938). A journal.

Lehrbuch der Physiologie in Vorlesungen. 4 vols. Berlin: Urban & Schwarzenberg, 1925–1927.

Gedanken eines Biologen zur Schaffung einer Völkergemeinschaft und eines dauerhaften Friedens. Zürich: Rascher, 1947.


Deichmann, Ute, and Benno Müller-Hill. “The Fraud of Abderhalden’s Enzymes.” Nature 393 (1998): 109–111. Presents an extreme point of view.

Frewer, Andreas. Medizin und Moral in Weimarer Republik und Nationalsozialismus: Die Zeitschrift “Ethik” unter Emil Abderhalden. Frankfurt, Germany, and New York: Campus Verlag, 2000.

Gabathuler, Jakob. Emil Abderhalden: Sein Leben und Werk. Wattwil, Switzerland: Abderhalden-Vereinigung, 1991.

Kaasch, Michael. “Sensation, Irrtum, Betrug?—Emil Abderhalden und die Geschichte der Abwehrfermente.” Acta Historica Leopoldina 36 (2000): 145–210.

Kaasch, Michael, and Joachim Kaasch. “Wissenschaftler und Leopoldina-Präsident im Dritten Reich: Emil Abderhalden und die Auseinandersetzung mit dem Nationalsozialismus.” Acta Historica Leopoldina 22 (1995): 213–250.

———. “Emil Abderhalden: Ethik und Moral in Werk und Wirken eines Naturforschers.” In Medizingeschichte und Medizinethik: Kontroversen und Begründungsansätze, 1900–1950, edited by Andreas Frewer and Josef N. Neumann, 204–246. Frankfurt, Germany, and New York: Campus Verlag, 2001.

Kessler, Stanley, and Gustav J. Martin. “The Abderhalden Reaction: A Review of the Literature on the Defense Proteinases (Abwehrfermente).” Experimental Medicine and Surgery 16, nos. 2–3 (1958): 190–212.

Wolf, George. “Emil Abderhalden: His Contribution to the Nutritional Biochemistry of Protein.” Journal of Nutrition126 (1996): 794–799.

Michael Kaasch

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