Sir Hans Adolf Krebs (1900 – 1981) – Part 3

Hans Krebs discovered the citric acid cycle (or “Krebs cycle”) and the urea cycle and received the Nobel Prize in Physiology or Medicine in 1953. In this part, we look at the Nobel Prize and Krebs’ thoughts about life as a displaced person.

6. Hans Krebs, Fritz Lipmann, and Hermann Staudinger

The selection of the Nobel Prize winners for 1953 could be viewed as successful messaging on the part of the Nobel Prize committee. The Nobel Prize for Medicine or Physiology was shared by Hans Krebs for the discovery of the citric acid cycle and Fritz Lipmann for the discovery of coenzyme A, and the Nobel Prize for Chemistry was given to Hermann Staudinger, founder of polymer chemistry.

Only a few years after the end of the war, Germany could have been proud of three of its citizens, if two of them had not been driven out by the Nazis and ceased being Germans long before: Krebs had become British, Lipmann American. The third in the group, Hermann Staudinger [19], also had considerable difficulties with the Nazis.

Staudinger and Krebs both worked at the University of Freiburg in 1933. There, the rise of National Socialism had a face: that of philosopher Martin Heidegger. He put his signature on Hans Krebs’ termination on July 15, 1933, and denounced Hermann Staudinger in February of 1934 because of his open pacifism in World War I [20].

In 1953, the Nobel Prize made it clear to the Germans that the country had driven a large proportion of its cleverest minds out through a forced mass exodus. Today, many might say that this was all a long time ago and is long past. This is false, because it was not only Nobel Prize winners, but also many doctors, physicists, mathematicians, philosophers, writers, painters, musicians, etc. who were shamefully driven out. This bloodletting still has effects today, because most never returned. Sometimes, a list says more than a thousand words (see Tab. 2).

Table 2. Nobel Prize winners driven from their positions and countries by Hitler and Mussolini [23].


Name	Field	Year

Hans Bethe	Physics	1967
Felix Bloch	Physics	1952
Konrad Bloch	Physiology or Medicine	1964
Max Born	Physics	1954
Ernst Boris Chain	Physiology or Medicine	1945
Max Delbrück	Physiology or Medicine	1969
Albert Einstein	Physics	1921
Enrico Fermi	Physics	1938
James Franck	Physics	1925
Dennis Gabor	Physics	1971
Fritz Haber	Chemistry	1918
Gerhard Herzberg	Chemistry	1971
Victor Hess	Physics	1936
Georg von Hevesy	Chemistry	1943
Erik Kandel	Physiology or Medicine	2000
Bernhard Katz	Physiology or Medicine	1970
Hans Krebs	Physiology or Medicine	1953
Rita Levi-Montalcini	Physiology or Medicine	1986
Fritz Lipmann	Physiology or Medicine	1953
Otto Loewi	Physiology or Medicine	1936
Salvador E. Luria	Physiology or Medicine	1969
Otto Meyerhof	Physiology or Medicine	1922
Wolfgang Pauli	Physics	1945
Max Perutz	Chemistry	1962
John Polanyi	Chemistry	1986
Erwin Schrödinger	Physics	1933
Emilio Segrè	Physics	1959
Otto Stern	Physics	1943
Richard Willstätter	Chemistry	1915

7. Krebs’ First Visits to Germany after 1945

What repercussions did Krebs’ fate as a displaced person have on his relationship with Germans after 1945? He reported on his first visit to heavily damaged Hildesheim [1]:

“I am often asked how I feel about my homeland as a displaced person, a country in which a government committed incomprehensible crimes against humanity and my closest relations and friends, a government that was supported by a large proportion of the population. My feelings about this are by no means the result of homesickness, because as much as I loved Hildesheim, my early love for England and its people quickly led this to become my true home. But I never had the notion of identifying all Germans as Nazis, and to therefore blame them or to feel hostile toward them. My personal belief in the decency of the majority of them was confirmed again and again by my personal experiences.

I know that most Germans were not more decent or heroic than people elsewhere; I know that they were forced by circumstance, in view of the enormous pressure and intimidation of Nazi violence, to stand on the sidelines. If you wanted to survive, you had to come to terms with the regime on a daily basis and to serve it, because the Nazis used horrible threats against the families of individuals who showed signs of resistance. …

After the war, it was difficult for the Allies to find any people who admitted to having been Nazis, and we will never really know exactly how many supported Hitler of their own free will. I approximate that at certain times it may have been approaching to or more than half of the population. But to be anti-German for this reason seems to me to be just as bad as being antisemitic. Many emigrants hold the opposite position. For them, it is impossible to ever set foot in the land of their birth again after the cruelty, murders, robbery, and atrocities they experienced.

My first visit to Germany was at the end of August 1949, after a sixteen-year absence. … I discovered that it moved me more than I ever thought it would. During the train journey, I couldn’t read as I normally do during train journeys. Instead, I regarded the landscape. Many sights seemed so familiar to me; they were part of my native origin. At the same time, knowledge of the history of the last 16 years influenced my feelings, especially towards the people. Which of these normal-looking people welcomed Hitler and followed him unconditionally to the end? Who among them was a member of the loathsome Gestapo? Who among them had seen clearly the crimes Hitler ordered? Who among them had actively participated in the horror of the death camps, in which more than twenty of my own relatives were killed? …

The charm of medieval Hildesheim, which I knew before the war, was completely lost. … The people are different from the old inhabitants. Only a few use the old, local dialect and the typical turns of phrase I was so familiar with. The speech of most of them was colorless, often not nice, and sloppy. This was another change that strengthened my feeling of no longer belonging to my birthplace.”

Hans Krebs did not just talk about his unprejudiced attitude toward the Germans, he also acted on it. For example, he attempted to reintegrate German researchers into the international scientific community after World War II. He did this without reservation, though aware of the things that had happened. We can all ask ourselves if we would have acted in the same way after such a personal history.

For the “First International Congress in Biochemistry” in Cambridge, UK, in 1949, the organizational committee had bowed to pressure from continental biochemists and extended no invitations to German participants. Krebs opposed this and advocated the view that three years after the end of the war, such restrictions should be a thing of the past. As a refugee, he felt a special responsibility for the normalization of relations with Germany. In the end, Krebs partially prevailed and four invitations were extended to Germans, including Theodor Wieland.

The Germans were impressed with Krebs’ noble stance and thanked him, both personally and officially: He was given an honorary doctorate by his old University of Freiburg, was made a citizen of honor in Hildesheim, and the German President awarded him the Order of Merit of the Federal Republic of Germany. Even his funeral in Oxford was impressive. The funeral service was held in the Anglican Church, and the coffin was covered with a German flag. Maybe Germans should also—as is partially done in the Anglo-American literature—refer to the citric acid cycle as the “Krebs Cycle” in their textbooks.

Hans Krebs’ fate is not typical for a Jewish scientist at the start of the Nazi dictatorship. Most of them suffered a much more difficult or terrible fate. With his discovery of the urea cycle, he was lucky to have made a significant discovery at a young age. His admiration of the English way of life, with its courtesy, tolerance, and humor, made England his first choice, and thanks to his international reputation, he was quickly able to find an opportunity to continue his work in Cambridge. Despite his love for his homeland, particularly Hildesheim, his departure from Germany was relatively easy, because he had no family of his own, no money, and was young enough to start anew. Many others had a much more difficult fate.

Hans Krebs once confessed that he had not always appreciated how lucky he was. He admitted that luck is necessary to be successful in experimental science, but it was also clear to him that the more experiments one carries out, the higher the probability of getting lucky [21].

Acknowledgements

All documents used for this article were bequeathed to the University of Sheffield, UK, by Hans Krebs. Among them were many German newspaper clippings and flyers from the period between 1932 and 1933. These documents were so important to Hans Krebs that he took them along when he emigrated and kept them throughout his entire life. Only shortly before his death did he report about his expulsion in a publication titled “How I Was Expelled from Germany – Documents with Commentary” [22]. This paper, his autobiography [1], and the impressive work of scientific history by F. H. Homes [12] served as the basis for this article. The data about the political environment in 1932–33 was largely taken from the booklet “National Socialism I” from the series “Information for Political Education” published by the German Federal Agency for Civic Education.

I thank Professor L. Jaenicke, Cologne, Germany, for his valuable suggestions and support, and Dr. Pamela Winchester, Berlin, Germany, for her help in completing this manuscript. Special thanks to the Chemical Industry Fund (FCI) for the rapid and unbureaucratic support of my visit to the archive in Sheffield. I also very particularly thank Jacki Hodgson and her colleagues in the special collections at the University of Sheffield library for their hospitality and tremendous help with this work.