Otto Heinrich Warburg (German pronunciation: [ˈɔto ˈvaːɐ̯bʊʁk] , ; 8 October 1883 – 1 August 1970) was a German physiologist, medical doctor, and Nobel laureate. He served as an officer in the elite Uhlans (cavalry) during the First World War, and was awarded the Iron Cross (1st Class) for bravery. He was the sole recipient of the Nobel Prize in Physiology or Medicine in 1931. In total, he was nominated for the award 48 times over the course of his career.
Otto Heinrich Warburg was born in Freiburg im Breisgau on 8 October 1883, close to the Swiss border. Otto's mother was the daughter of a Protestant family of bankers and civil servants from Baden. His father, Emil Warburg, had converted to Protestantism as an adult, although Emil's parents were Orthodox Jews. Emil was a member of the illustrious Warburg family of Altona. Emil was also president of the Physikalische Reichsanstalt, Wirklicher Geheimer Oberregierungsrat (True Senior Privy Counselor).
Otto Warburg studied chemistry under Emil Fischer, and earned his doctorate in chemistry in Berlin in 1906. He then studied under Ludolf von Krehl and earned the degree of doctor of medicine in Heidelberg in 1911.
Between 1908 and 1914, Warburg was affiliated with the Naples Marine Biological Station, (in Naples, Italy), where he conducted research. In later years, he would return for visits, and maintained a lifelong friendship with the family of the station's director, Anton Dohrn.
A lifelong equestrian, he served as an officer in the elite Uhlans (cavalry) on the front during the First World War, where he won the Iron Cross. Warburg later credited this experience with affording him invaluable insights into "real life" outside the confines of academia. Toward the end of the war, when the outcome was unmistakable, Albert Einstein, who had been a friend of Warburg's father Emil, wrote to Warburg at the behest of friends, asking him to leave the army and return to academia, since it would be a tragedy for the world to lose his talents. Einstein and Warburg later became friends, and Einstein's work in physics had a great influence on Warburg's biochemical research.
Scientific work and Nobel Prize
While working at the Marine Biological Station, Warburg performed research on oxygen consumption in sea urchin eggs after fertilization and showed that upon fertilization the rate of respiration increases as much as sixfold. His experiments also showed that iron is essential for the development of the larval stage.
In 1918, Warburg was appointed professor at the Kaiser Wilhelm Institute for Biology in Berlin-Dahlem (part of the Kaiser-Wilhelm-Gesellschaft). By 1931 he was named director of the Kaiser Wilhelm Institute for Cell Physiology, which had been founded the previous year by a donation of the Rockefeller Foundation to the Kaiser Wilhelm Gesellschaft (since renamed the Max Planck Society).
Warburg investigated the metabolism of tumors and the respiration of cells, particularly cancer cells, and in 1931 was awarded the Nobel Prize in Physiology for his "discovery of the nature and mode of action of the respiratory enzyme". In particular, he discovered that animal tumors produce large quantities of lactic acid. The award came after receiving 46 nominations over a period of nine years beginning in 1923, 13 of which were submitted in 1931, the year he won the prize.
The Nobel laureate George Wald, having completed his Ph.D. in zoology at Columbia University, received an award from the U.S. National Research Council to study with Warburg. During his time with Warburg, 1932–1933, Wald discovered vitamin A in the retina.
When the Nazis came to power, people of Jewish descent were forced from their professional positions, although the Nazis made exceptions. Warburg had a Protestant mother and a father with Jewish heritage (who had converted to Protestantism). According to the Reichsbürgergesetz of 1935 (cf. Nuremberg Laws), he was a Halbjude (half-Jew) or Mischling.
Nazi anti-homosexuality policy posed a further risk to Warburg due to his relationship with Jacob Heiss. Beginning around 1918, Heiss served variously as Warburg's personal aid, secretary, and administrative assistant.
The couple lived together in an elegant villa in Dahlem, in Berlin.
Warburg was banned from teaching, but allowed to carry on his research. In 1941, he briefly lost his post for making remarks critical of the Nazi regime, but in a few weeks was able to resume his research following a personal order from Hitler's Chancellery. Hermann Göring also arranged for him to be classified as one-quarter Jewish. In September 1942, Warburg made an official request for equal status (Gleichstellung) with German Aryans, which was granted.
The Nazis were willing to allow Warburg to work because of his focus on metabolism and cancer. Hitler was obsessed with cancer, having lost his own mother to breast cancer at an early age. The decisive factor was Warburg's distinguished military service in the Great War, as Jewish veterans were often exempted from the loss of citizenship mandated by the Nuremberg laws. Warburg's Germanic physiognomy may also have weighed in his favor, as Hitler's Chancellery is known to have factored in eye color and face shape when evaluating Aryanization applications.
Warburg disagreed with the Nazi regime, and refused to acknowledge the Nazi salute, to the point of provoking retaliation from its officers. Authors have speculated on why he stayed in Germany under the Reich. Apple suggests that, like many others, he did not imagine how bad things could get. His own egotism may have led him to underestimate the potential threat posed by the Nazis.
Others have suggested that Warburg was so totally devoted to his work that he was prepared not only to stay in Germany but to tolerate the treatment of his Jewish colleagues and relatives by the Nazis. An anecdote from Birgit Vennesland, who became a director at Warburg's institute in West Berlin in 1968, is suggestive. She said that Warburg's advice for an acquaintance who was experiencing emotional difficulties was "Tell him not to think about anything but science—think about absolutely nothing else—only science."
In 1943 Warburg relocated his laboratory to the village of Liebenburg on the outskirts of Berlin to avoid ongoing air raids.