At the start of the 20th century, the German Empire was the undisputed hub of the scientific universe. From 1901, when the Nobel Prizes were established, through 1932, Germans won almost a third of all the Nobels awarded to scientists — 31 in total. (American scientists, in contrast, won five during the same time period.) This impressive track record was fueled, in part, by Jewish researchers who just decades earlier would have been excluded from prominent academic positions. When the Nazis seized power in March 1933, it was not unusual for major scientific institutes to be led by Nobel laureates with Jewish roots: Albert Einstein and Otto Meyerhof, both Jewish, ran prestigious centers of physics and medical research; Fritz Haber, who’d converted from Judaism in the late 19th century, ran a chemistry institute; and Otto Warburg, who was raised as a Protestant but had two Jewish grandparents, was the director of a recently opened center for cell physiology. But that acceptance of diversity, as well as Germany’s scientific dominance, was about to change. Einstein, who was out of the country when Hitler was granted near-dictatorial powers, never returned. Haber resigned his post and emigrated to Britain. The 49-year-old Warburg, on the other hand, was not about to go anywhere. His newly opened institute had been designed to his exacting, eccentric specifications (it was modeled after a rococo, 18th-century country estate he’d seen in Potsdam), and his lab was staffed with instrument specialists and technicians whom he’d spent years training to his rigorous standards. His longtime live-in assistant, a younger man widely assumed to have been Warburg’s lifelong lover, served as all-purpose gatekeeper and enforcer. Image But even the self-centered, single-minded Warburg could ignore the realities around him for only so long. On Jan. 16, 1934, a Nazi customs official arrived at Warburg’s lab in Dahlem, a suburb of Berlin, demanding to know why he had not completed a “declaration of Aryan descent.” The farce that ensued, which included several weeks of posturing and insults, ended in a kind of stalemate: In the future, the Kaiser Wilhelm Society for the Advancement of Science, which oversaw his institute, would order any supplies Warburg required. Warburg, however, was not satisfied, and told the society’s director that anyone running one of its many institutes should be treated as Aryan. “In 1934, at a moment when Hitler had already begun sending Germans to concentration camps,” the journalist and author Sam Apple writes at the end of this opening anecdote in “Ravenous,” “Otto Warburg, a gay man of Jewish descent, wanted Nazi laws rewritten according to his personal needs.” That crackerjack opening highlights both the strengths and weaknesses of “Ravenous”: Apple has a tendency to undercut his vivid scene setting by raising the emotional stakes beyond what the evidence supports. While the Nazis were putting their political opponents in detention camps in 1934, these were roughly akin to the camps the United States used to forcibly relocate Japanese Americans during World War II. It would be another five years before the Nazis began rounding up and systematically murdering Jews, Roma and anyone else they deemed racially inferior. Warburg’s research in the 1920s and 1930s into how living organisms transform fuel, in the form of oxygen and glucose, into energy made him one of the giants of biochemistry. When he won the Nobel Prize in Physiology or Medicine in 1931 for his discovery of the enzyme that triggers our cells to break down glucose molecules with oxygen, it capped a remarkable nine-year period in which he was nominated a total of 49 times. (That could explain his reaction on learning that he had won: “It’s about time.”) Editors’ Picks ‘Boyz N the Hood’ at 30: A Vivid Examination of White Supremacy at Work Why Jane Goodall Still Has Hope for Us Humans ‘I Came Across a Guy Who Was Sitting on the Curb With a Guitar’ Continue reading the main story Image Sam Apple Sam AppleCredit...Mark Tassoni The research that Warburg is best known for today, and the work that forms the backbone of “Ravenous,” is his discovery that cancer cells behave differently from healthy cells in two very specific ways: They consume massive amounts of glucose — Apple compares them to ravenous shipwrecked sailors — and they eschew aerobic respiration in favor of fermentation. The first two-thirds of “Ravenous” are primarily concerned with questions about Warburg’s life and work: Out of more than 100 scientists from the Kaiser Wilhelm era who met the Nazi definition of being Jewish in 1933, why was it Warburg alone who remained alive and working in Germany by the time the Nazis were finally defeated? And why was his groundbreaking research on cancer metabolism all but forgotten by the end of the 20th century? Apple covers everything from Hitler’s obsessive preoccupation with cancer to how the German Empire’s transformation into an industrial powerhouse led to a Romanticism-fueled movement that emphasized both environmental and racial purity. The fact that Apple can make these stories, many of which have been told before, feel so immediate is a testament to his canny knack for choosing apposite details. When he attempts to unravel the conundrums at the center of Warburg’s life, however, he is hamstrung by a dearth of primary sources: The only personal reflections of Warburg’s that Apple quotes — and perhaps the only instances of Warburg ever recording his private thoughts — come from a few short diary entries scribbled on the back of one of his lab notebooks in the final weeks of the war. Apple relies as a result on the diaries of Warburg’s sister, Lotte, which were published in German after her death, and a cascade of speculative conditionals to describe how Warburg “would have,” “must have” or “likely” felt. The Otto Warburg who emerges from this pastiche is someone who today would be described as a toxic personality: petty and self-centered, obsessed with real and imagined slights, and always convinced of his own brilliance. Those qualities go a long way toward explaining why Warburg’s work on cancer was neglected for so long: His insights about fermentation were often obscured by his insistence, long after evidence had proved him wrong, that cancer cells fermented glucose because they were unable to use oxygen. But Warburg’s unpleasant personality does not explain why the Third Reich tolerated him. It’s not because he fell into line: Warburg banned the Nazi flag and Nazi salute from his institute and had no Nazis on its staff. Apple attempts to answer this question with allusions to some dark evil, returning again and again (and again) to the idea that Warburg was a “true Faust,” someone so “ravenous for knowledge and power” that he would do anything, including sell his soul to the devil, to achieve “full mastery over life.” But it’s never clear what, precisely, that is supposed to mean. In the end, Warburg’s biggest sin seems to have been that he not only remained in Germany but survived. Apple ends the first chapter detailing Warburg’s life after the war with an anecdote about a dinner party in America during a 1949 trip that he hoped would result in employment. The greatest obstacle to achieving this goal, Apple writes, “might have finally dawned on Warburg” when the wife of a Caltech professor asked him why he’d remained in Germany “when the Nazis were doing such bad things.” The scene then played out: “‘I wanted to protect my co-workers,’ Warburg lied. ‘What could I have done?’ The woman had an idea: ‘You could have committed suicide!’ Warburg and the other dinner guests sat stunned. Someone had finally informed the Emperor of Dahlem of his missing clothes.” Over the past decade, the natural ebb and flow of science has caused Warburg’s work on cancer to gain new recognition: As the initial promises of the genetic revolution have not been borne out — the discovery of oncogenes did not, as many had hoped, bring about the end of cancer — there’s been a renewed interest in studying the mechanisms that cancer cells use to thrive. Today, cancer cells relying on fermentation when oxygen is available is known as the Warburg effect. This recent focus on how cancer cells are powered brings us to the other mystery Apple tackles: Why did cancer, one of modern civilization’s most intractable killers, become “so much more common across the Western world starting in the 19th century”? Ever since the early 1960s, the most persistent theory has been that we are being infected by the chemicals and plastics that pervade modern life. The evidence, however, has not backed this up: Exposure to chemicals can be cancerous, but chemicals are not the all-purpose boogeyman they were once thought to be. Recently, however, a new potential culprit has come into view. A flurry of research strongly linking excess body fat to everything from pancreatic and thyroid cancer to ovarian and uterine cancer has led some researchers to label obesity as the second major cause of cancer, trailing only tobacco. While the links here are compelling — as Apple puts it, “The way we eat must somehow be connected to the way that cancers eat” — Apple is less adept at explaining cutting-edge science than at making history come alive. But if the chapters explaining the links between glucose, insulin and cancer are not among Apple’s strongest, the gist of what he’s saying should still lead readers to think twice the next time they reach for a soft drink.