AS WARBURG SEARCHED for a cure for cancer in the late 1930s, Louis Pasteur and Paul Ehrlich were not the only two scientists gazing down at him from the walls of his library. The third and final scientist whose portrait hung in Warburg’s library was Robert Koch. Though Pasteur is often credited with persuading the nineteenth-century scientific establishment that tiny, invisible animals were responsible for most diseases, the idea continued to seem preposterous to much of the medical world during Pasteur’s lifetime. “I am afraid that the experiments you quote, M. Pasteur, will turn against you,” an 1860 editorial in the French scientific journal La Presse warned. “The world into which you wish to take us is really too fantastic.”1
Infectious diseases were widely thought to be spread not by living germs but by bad, or contaminated, air. And while Pasteur showed that fermenting microorganisms could be found in diseased plants and animals, he couldn’t convincingly demonstrate that the microbes were the true cause of the disease. It was entirely possible, as skeptics of germ theory pointed out, that the symptoms arose first and that the bacteria, like nomads settling in a conquered city, merely took advantage of the newly defenseless tissue. “My heart says ‘yes’ to bacteria,” one surgeon of the era wrote, “but my reason says ‘wait, wait.’ ”2
It was Robert Koch, a country doctor carrying out experiments in his home laboratory, who finally won over most skeptics of germ theory. In the 1870s, Koch, like other researchers before him, observed that the blood of a mouse that had died of anthrax always contained the same specific bacteria. They looked like little rods under Koch’s microscope and could turn into small bead-like spores. Koch found that if he injected the diseased blood into a healthy mouse, the animal would soon develop anthrax and die. But such experiments were far from conclusive. There are countless different molecules in blood, and in theory, any one of them might have been responsible for transferring the disease. Koch’s challenge was to find a way to determine if the bacteria were the true cause of anthrax. To do so, he realized, he would first need to grow the organisms outside of a living animal. He could then inject the newly grown bacteria into healthy mice and observe if the animals developed anthrax.
Koch grew the germs in fluid taken from the eye of an ox. To gather enough mice to test, he and his wife set traps around their barn. In the spring of 1876, after he had seen, in experiment after experiment, that the bacteria alone caused healthy mice to develop anthrax and die, he demonstrated his experiments in front of a group of prominent scientists in Breslau. It was a monumental moment in the history of science, yet it was only Koch’s opening act. Six years later, a nervous Koch stood before the Berlin Physiological Society, and speaking slowly and deliberately, made a world-changing announcement: he had found the specific germ responsible for tuberculosis, the disease that killed more people in the Western world than any other.3
Koch had not found a cure for tuberculosis. What he had found, as with anthrax, was causality. The “bacilli which are present in the tuberculosis substances not only accompany the tuberculosis process,” Koch told his colleagues, “but are the cause of it.” A young Paul Ehrlich in the audience that night later described it as “the most important experience” of his “scientific life.” Ehrlich would spend the remainder of his career looking for magic bullets, but it was Koch who had found the targets for Ehrlich to shoot.4
As news of Koch’s tuberculosis discovery spread, he became world famous, perhaps the most respected German alive when Otto Warburg was a child. German merchants sold some 100,000 red handkerchiefs that depicted Koch together with Kaiser Wilhelm and Otto von Bismarck. In the summer of 1884, the New York Times described Koch as “the man whose name is at present in everybody’s mouth,” and his fame would grow greater still in the following years, after he claimed to have found a cure for tuberculosis.5
An 1890 article in a British journal wrote of the “Koch boom” and depicted Koch riding on a white horse, his microscope held above his head like a sword ready to strike an attacking serpent labeled “tuberculosis bacilli.” The author of the article had recently traveled through a tuberculosis-stricken region of Italy where rumors of Koch’s cure led to a frenzy of excitement: “[T]he news that the German scientist had discovered a cure for consumption must have sounded as the news of the advent of Jesus of Nazareth in a Judean village. The whole country was moved to meet him.”6
Never mind that Koch’s tuberculosis treatment proved a great disappointment. By then, Koch was the living embodiment of science’s triumph over disease and misery. The Germans had placed their faith in science in the late nineteenth century, and Koch, more than anyone, promised the salvation they sought.
Koch won the Nobel Prize in Physiology or Medicine in 1905, when Warburg was in his early 20s and Hitler was 16. By then he had found the germ responsible for cholera as well. Outside of Germany, Koch is best remembered for a set of criteria, Koch’s postulates, long used to determine whether a given microbe could be considered the true cause of a disease. His first postulate states that if a microbe is the cause of a disease, it must be present in every last case of the disease. In 1966, in perhaps Warburg’s best-known statement on cancer, Warburg would use nearly identical language:
There are prime and secondary causes of diseases. For example, the prime cause of the plague is the plague bacillus, but secondary causes of the plague are filth, rats, and the fleas that transfer the plague bacillus from rats to man. By a prime cause of a disease I mean one that is found in every case of the disease. Cancer, above all other diseases, has countless secondary causes. But, even for cancer, there is only one prime cause. Summarized in a few words, the prime cause of cancer is the replacement of the respiration of oxygen in normal body cells by a fermentation of sugar.7
Later, in the same speech, Warburg made the connection to Koch explicit: “Only today can one submit, with respect to cancer, all the experiments demanded by Pasteur and Koch as proof of the prime causes of a disease.”
ADOLF HITLER WAS born in 1889, six years after Otto Warburg, and he, too, came to see himself in the reflection of the most celebrated German man of his youth. Koch, arguably, had a far greater influence on Hitler than on Warburg. In one sense, Koch shaped Hitler’s life simply by proving that germs cause disease. Germ theory was not an abstraction for Hitler. He lost at least two siblings to infections and claimed in Mein Kampf to have suffered from a serious lung illness as a child. Like many others at the time, he suspected that germs could also cause cancer, the disease that ravaged his mother. As the years passed, Hitler became increasingly fearful of germs and washed his hands more and more often. He was said to hate being touched. He took to quarantining members of his entourage when he feared they were sick and eventually to making everyone he came in contact with prove they weren’t sick or contagious.8
A fear of germs was common then, as it is today, among people of all political outlooks. As Pasteur once observed, “It is terrifying to think that life may be at the mercy of the multiplication of those infinitesimally small creatures.” For Hitler, Koch meant something more than germaphobia. Hitler grew up in the age of Koch, when nearly every last disease could suddenly be tied to a specific hidden cause and, more important, when the work of identifying and eliminating the underlying cause of a disease was grounds for deification.9
Koch’s language of cause and effect appears in Hitler’s writing and speeches again and again. “The cure of a sickness can only be achieved if its cause is known, and the same is true of curing political evils,” Hitler wrote in Mein Kampf. “To be sure, the outward form of a sickness, its symptom which strikes the eye, is easier to see and discover than the inner cause. And this is the reason why so many people never go beyond the recognition of external effects and even confuse them with the cause, attempting, indeed, to deny the existence of the latter.”10
Hitler borrowed from Koch’s bacteriological jargon from the start of his political career, with obvious targets in mind. In August 1920, at a meeting of the Nazi Party in Salzburg, Hitler described Jewish influence on German life as “racial tuberculosis.” “The impact of Jewry will never pass away, and the poisoning of the people will not end,” Hitler said, “as long as the causal agent, the Jew, is not removed from our midst.”11
Whether Hitler was aware that he was invoking Koch as he wrote those words is impossible to know. But Koch was in Hitler’s thoughts in September 1939, at the start of the Second World War. That same month, the Nazi filmmaker Hans Steinhoff released a biographical film portraying Koch as a visionary genius with the strength and determination to ignore all those who doubted that bacilli were the true cause of disease. Hitler was delighted with the film and sent Steinhoff a congratulatory telegram. “To give you one-and-a-half hours of pleasure,” Steinhoff wrote back, “is a stimulus for me and a deeply felt wish.”12
In 1941, amid a middle-of-the-night rant, Hitler, hardly a self-aware man, had a flash of insight: “I feel like the Robert Koch of politics,” he said. “He found the bacillus of tuberculosis and through that showed medical scholarship new ways. I discovered the Jews as the bacillus and ferment of all social decomposition.”13
BY 1941, Otto Warburg had been stripped of his title of “university professor.”14 Though he had managed to hang on to his institute, he was now isolated from the outside world and in considerable danger. There were no more visits from Rockefeller Foundation officials, no new foreign students visiting his institute. Warburg had made his deal with the devil, and his payment was coming due. With the start of the war, whatever propaganda value a living Warburg had once held for the Nazis was gone. “Anyone who had official obligations to support the ministry washed their hands of me,” Warburg later said.15
Worst of all for Warburg, tolerance of half-Jews, the so-called first-degree Mischlinge, was running low. According to one census, there were still some 60,000 half-Jews in Germany. Adolf Eichmann, the Nazi official in charge of deporting Jews, wanted the Nuremberg Laws revised so that these remaining first-degree Mischlinge could be considered “full Jews” and deported along with the rest.16
While some government officials continued to push for the protection of quarter-Jews (second-degree Mischlinge), half-Jews such as Warburg, it was widely agreed, could never be assimilated into German society. The only remaining question was whether first-degree Mischlinge should be included in the deportations, as Eichmann hoped, or merely forcibly sterilized.
Given the debate about half-Jews taking place in 1941, Warburg’s continued presence at the Kaiser Wilhelm Society came to seem all the more outrageous to some Nazi officials. A first-degree Mischling was not only still working freely in Germany but running an institution where he commanded a team of Aryans with military-like discipline. The situation was untenable. In the spring of 1941, Rudolf Mentzel, who headed the science division at the Reich Education Ministry, together with another influential Nazi medical official, decided to remove Warburg from his institute so that it could be used as a home for a newly established central cancer agency. Warburg, of all people, was to be sacrificed in the name of cancer science.
On April 5, 1941, the two Nazi leaders met with the secretary general of the Kaiser Wilhelm Society, Ernst Telschow, to explain their intentions for Warburg’s institute. Two weeks later, the plan was formally approved. Warburg was dismissed on the grounds that he was “of Jewish offspring.” He was to resign and leave the building by June 30, 1941. Warburg had survived in his position longer than anyone in Nazi Germany with two Jewish grandparents could have expected. His time had run out.17
The only account of Warburg during this period comes from Antonietta Dohrn, the granddaughter of the founder of the Naples Zoological Station, who recalled that Warburg, while deeply depressed, never relinquished his righteous fury. Dohrn overheard a phone conversation in which Warburg referred to Mentzel as “swine.” Asked if he was concerned that his phone was tapped, Warburg said that he hoped it was and that his tormentors wouldn’t know what to do in the face of civil courage.18
Though Warburg likely spent most of the spring of 1941 in a state of uninterrupted rage, he was still capable of acting strategically. He had connections at the highest levels of German society, and he did not hesitate to call on them. One of those connections, the famed surgeon Ferdinand Sauerbruch, knew Hitler personally. Walter Schoeller—the chemist who determined that the molecule Warburg had found in horse blood was nicotinamide—proved to be Warburg’s most important friend. Schoeller was a prominent chemist at a leading chemical company and served on the board of Warburg’s institute, but he was not, himself, especially influential in Nazi Germany. Schoeller’s wife, Paula, by contrast, was the sister-in-law of Philipp Bouhler, the head of the Chancellery of the Führer.
Bouhler, once deemed the most “shadowy” of all the Nazi leaders, was soft-spoken and had a scholarly disposition. Before joining the Nazis early on, he had studied philosophy and literature at Munich University, where he had also written plays and poems. In late 1939, together with his trusted deputy, Viktor Brack, Bouhler had instituted the Nazis’ first systematic killing program, which became known as Aktion T4 after the war. The goal was to eliminate the severely disabled, the so-called useless eaters who were consuming nutrients that might otherwise go to the healthy. It was Bouhler who had the idea to disguise the rooms in which the victims would be gassed as showers.19
When Walter and Paula Schoeller reached out to Bouhler on Warburg’s behalf, they did not ask him to protect someone of Jewish heritage. They asked, instead, for something stranger, a notion that could only exist in the phantasmagoria that was Nazi Germany: they asked to have Otto Warburg legally cleansed of his Jewish blood by way of a German Blood Certificate, which would have declared him legally equal to a German-blooded citizen. The process was informally known as Aryanization. The term is more commonly used in reference to Jewish businesses that were stolen by the Nazis, but when it suited their purposes, the Nazis could steal a soul as well.20
“Warburg’s willingness to let his Jewish blood be diluted in this way, and thus to make a pact with the Nazis, incensed colleagues outside Germany,” Hans Krebs wrote years later. But by the time Warburg applied for a German Blood Certificate, his life was in jeopardy. Warburg had already lied to his Nazi interrogators, however unconvincingly, about his Jewish heritage. While Warburg’s colleagues outside of Germany saw it as a refutation of his Jewishness, for Warburg, who didn’t think of himself as Jewish, there was little to refute. Krebs may have also failed to appreciate that Warburg’s effort to change his legal standing in Nazi Germany was not at all unusual. Based on 430 interviews with surviving Mischlinge and their relatives, the author Bryan Mark Rigg concluded that most Mischlinge were anxious to prove their “Aryanhood” at a moment when Germans considered them cowards and monstrosities. “Mischlinge internalized Nazi standards even as they tried to fight them,” Rigg writes.21
The exact number of half- and quarter-Jews who applied to have their legal status changed in Nazi Germany is unknown. Nazi records are incomplete and inconsistent. Petitions for authorization to continue to serve in the armed forces were more likely to succeed than petitions for German Blood Certificates, which were given out only infrequently. According to records of the Reich Ministry of the Interior, by May 1941, nearly 10,000 Mischlinge had applied for an upgraded legal status of one type or another, and 263 had been successful. (Scholars now believe the true numbers are considerably higher.) Hitler, growing frustrated with the number of special cases he was asked to consider, once complained that Nazi Party members “seem to know more respectable Jews than the total number of Jews in Germany.”22
In making the case for Warburg to be given the same legal status as the German-blooded, his supporters noted the pure Aryan heritage of his mother and his military service in World War I. But they also had a more compelling argument: Warburg was Germany’s best hope of curing cancer. To a nation desperate to defeat the disease, removing Warburg from his institute was tantamount to removing a great general in the middle of a war.23
Bouhler agreed that Warburg was worthy of Aryanization. But even with the support of the Chancellery of the Führer, Warburg’s fate remained uncertain. The Aryanization application at the time required photos (front and profile), military records, a written family history, and a statement of the applicant’s political views. The review process was known to take months or longer, and Warburg was slated to be removed from his institute in a matter of weeks.24
On June 14, Warburg’s supporters sent out a desperate plea. The letter appears to have been intended for Hermann Göring, whose power and influence was then second only to Hitler’s. (Göring once claimed that it was up to him to decide “who is a Jew and who is Aryan.”) The letter indicated that Warburg already had the support of the Chancellery of the Führer and implored Göring to lend his support to Warburg’s cause: “To remove Warburg and put someone else in charge of his institute” would “amount to the greatest spiritual robbery in the history of science.” Hans Krebs wrote that Göring intervened on Warburg’s behalf, but there are no records of Göring’s involvement.25
Meanwhile, Bouhler put his deputy, Brack, in charge of the case. Like Bouhler, Brack was a quietly ambitious SS bureaucrat. He was known as polite, even meek, at once scheming for power and dreading his rivals within the party. Underneath his drab exterior—he resembled the pitchfork-holding farmer in Grant Wood’s American Gothic—was a vivid imagination for the macabre. Brack once sent a memo to Himmler suggesting how millions of Jews might be sterilized unknowingly. According to the plan, Jews would be forced to fill out forms at counters in a government office. As the Jews toiled over the meaningless documents, X-ray machines hidden beneath the counters would irradiate their genitals.26
One week after the letter to Göring went out and nine days before Warburg was to be removed from his institute, Viktor Brack summoned him to the New Reich Chancellery, the newly built neoclassical home of Hitler’s government. The marble floors of the New Reich Chancellery’s long galleries were so slippery the guards would sometimes stand by with a stretcher when elderly diplomats visited. As Warburg made his way through the building, his carefully polished Scottish wingtips would have clacked ominously with each step.
Brack would have been wearing his black SS uniform that day, his senior rank reflected by the oak-leaf patch on his collar. Warburg was joined by Ernst Telschow, the chairman of the Kaiser Wilhelm Society. (Warburg, believing Telschow had played a role in his dismissal, refused to share a car with him.) As Warburg sat in the very belly of the Nazi beast, Brack delivered the verdict. He did not grant Warburg a Certificate of German Blood—the application remained under review—but Warburg would be allowed to keep his institute on one condition: he would have to continue to work on cancer. “I did this,” Brack told Warburg, “not for you, not even for Germany, but for the world.”27
Warburg later said that Brack had “probably saved” his life that day, but Bouhler and Brack did not have the power to make such a decision unilaterally. Himmler’s appointment book shows that he met with Brack specifically to discuss Warburg that same day. And though Göring had boasted that he decided who was a Jew, the Nuremberg Laws explicitly state that this privilege was, in fact, officially reserved for Hitler.
Though he had credited Brack for saving him, Warburg never doubted that it was Hitler’s fear of cancer that made it possible for him to survive, and there is reason to believe that Warburg was right. Hitler took the Aryanization process extremely seriously, busying himself with the minutiae of applications for German Blood Certificates even during the most critical moments of the war. Hitler was particularly concerned with the photographs and would reject anyone who appeared stereotypically Jewish.28
Given that Hitler is known to have reviewed applications from Mischlinge hoping to be Aryanized in June 1941 and also that Warburg was a Nobel Prize winner working on a cancer cure, it is entirely possible he intervened on Warburg’s behalf prior to Warburg’s meeting with Brack. Göring might well have reached out to Hitler directly. There are even grounds for speculation that Hitler, who was in the Chancellery on the day of Warburg’s visit, was aware of Warburg’s meeting with Brack.
That the highest-ranking Nazis were focused, even for moment, on Warburg on June 21, 1941 is almost incomprehensible. That day was arguably the most critical moment of the entire Nazi project. Operation Barbarossa, the largest military operation in history, was scheduled to begin at dawn the next morning. The eastward push into Soviet territory would be the fulfillment of Hitler’s vision. In a single stroke he would secure “living space” and grain fields for generations of Germans, wipe out “Jewish Bolshevism,” and demonstrate to the British that the German war machine was invincible.
In the evening of June 21, hours after Warburg left the building, a nervous Hitler paced back and forth with Joseph Goebbels, his propaganda minister, preparing the radio announcement of Operation Barbarossa to be broadcast in the morning. “This cancerous growth has to be burned out. Stalin will fall,” Hitler remarked to Goebbels at one point in their conversation.29
That Hitler had turned to cancer as a metaphor wasn’t unusual. But shortly before going to bed at 2:30 a.m.—the start of Operation Barbarossa then only 1 hour away—the conversation between Hitler and Goebbels took an unlikely turn. With the future of Germany at stake, Hitler and his propaganda minister paused their planning to discuss recent developments in cancer research.
Though Goebbels included few details of the conversation in his diary, he mentioned the name Hans Auler, a researcher who believed he had found a cancer microbe in the 1920s and who had published a book comparing cancer cells to “revolutionaries.” The “fact that cancer was even broached seems puzzling,” Robert Proctor notes in The Nazi War on Cancer. “How did Germany’s political leaders find the time—hours before a major invasion—to discuss cancer and cancer research? Was this idle chitchat, designed to ease the tension, or was there something more at stake?”30 If Hitler had decided the fate of Otto Warburg earlier that day, it is perhaps somewhat less surprising that he was still thinking about cancer research that night.
There is another possible explanation for why Warburg might have lingered in Hitler’s mind that consequential night. Though the name had changed to “Barbarossa,” the secret plan to invade the Soviet Union had initially been known by another name: Operation Otto.
NOT LONG AFTER Hitler went to bed, 3 million German troops advanced into Soviet territory. “The most destructive and barbaric war in the history of mankind was beginning,” writes the historian Ian Kershaw. As the Germans raced eastward, they destroyed Stalin’s underprepared units wherever they encountered them. After the first days of the invasion, much of the Soviet air force had been wiped out—as many as 1,000 planes were destroyed. It looked as though the Germans might reach Moscow in a matter of weeks.31
Barbarossa marked not just the start of a new stage of the war, but the start of the Holocaust as well. As German forces advanced through Eastern Europe, SS death squads, together with German police and soldiers, went from town to town, shooting political enemies and Jews wherever they found them. At first they shot only men. Soon enough, Jewish women and children were being shot as well. One death squad commander complained that shooting civilians was placing an “emotional strain” on his men. To help manage the stress, Germans who shot children were provided with extra alcohol.32
On December 14, 1941, six months after the two had discussed the fate of Otto Warburg, Viktor Brack met again with Himmler. It was likely during this meeting, some historians have concluded, that the two men began planning the killing of all European Jews.