I’m on an Asimov binge. I occasionally go on Asimov binges, rereading well-used Asimov titles from the 1950s through the 1980s. In this case I was inspired to see what old Asimov articles on physics and chemistry might still be useful to my eldest daughter, who is 11. Asimov was such a great explainer of scientific concepts – the Periodic Table, states of matter, particle/wave duality, the formation of solar systems – that I’ve hung on to these books not only out of sentimentality but also in the expectation that they would be useful in the education of my children. Working against that, though, is the problem that science, of all fields, progresses, rendering some old descriptions out of date in the course of a generation.
I’m pleased to report that many of his decades-old essays are every bit as fascinating and elucidating as they ever were.
One thing that makes Asimov’s style so accessible is that he tends to tell the stories of discoveries chronologically. I don’t think he’s ever done that better than in his book The Collapsing Universe, in which he explains how black holes are formed and why they are interesting to scientists. Go to the Wikipedia page on black holes for comparison. It’s gibberish. It might all be correct, but in terms of being useful to a layperson trying to get a better understanding of black holes – Wikipedia is, after all, intended to be an encyclopedia – it’s next to useless.
What Asimov does, instead, is describe the the discovery of black holes (first theoretical, then astronomical) only after explaining such concepts as gravity, electromagnetism, the strong interaction, gas laws, density, the main sequence, white dwarfs, degenerate matter, tidal forces, and neutron stars. Rather than start with what is currently known, he works his way through the historical progression of ideas, describing the experiments of scientists along the way. It’s a very useful pedagogical technique, and one that makes science much more interesting.
Inspired by that, then, I was also, at the same time as I was reading about Asimov on chemistry and physics, preparing lectures for a physiological psychology class I am teaching this summer. A component of that class which is brutal for many students is learning about the neuron, the resting potential, and the action potential. I decided I would use the Asimovian technique of explanation-through-historical-progression, which led me to read about such Nobel Prize winning luminaries as Ramon y Cajal, Charles Sherrington, and Lord Adrian.
But that’s not what I came to tell you about. I came to talk about Adolf Hitler.
Physics and Chemistry
You see, the story of black holes that I was reading about on one hand, and the story of the development of neuroanatomy and neurophysiology that I was reading about on the other, are both stories that basically center on scientific discoveries of the first half of the 20th Century. Some of these discoveries occurred in the United States, but the majority took place in Europe, and a considerable number came out of laboratories of Germany, Austria, Italy, and other areas of Central Europe that were threatened, during the same time period, by the rise of Nazism and the insanity of Adolf Hitler. And many of the key scientists were Jewish.
Asimov tells one aspect of that story breathlessly in a fun little essay called “Neutrality!” (reprinted in the essay collection The Sun Shines Bright). The essay’s title comes from its focus on James Chadwick’s discovery of the neutron, the first subatomic particle discovered that was not affected by electromagnetic forces. Chadwick’s discovery, and Enrico Fermi’s later discovery that neutrons were effective missiles to bombard atomic nuclei with, inspired Leo Szilard to investigate the possibility of a nuclear chain reaction, a key step in the development of nuclear power – and nuclear weapons.
Szilard was Jewish, Austro-Hungarian, and, while Hitler was rising to power in Germany, was a lecturer in physics at the University of Berlin.
Szilard discussed his ideas early on with two other Jewish scientists who began their careers in Nazi-threatened areas of Europe – Chaim Weizmann and Albert Einstein. Although Weizmann had become a British citizen long before Hitler’s rise, Einstein famously left Germany in 1933 as a direct response to Hilter’s increasingly belligerent attitude towards Germany’s Jewish population.
And then there is the discovery of uranium fission by Otto Hahn and Lise Meitner. Hahn and Meitner began their researches together in Germany, but Meitner was an Austrian Jew. In 1938 she had to be smuggled out of the country, carrying a diamond given to her by Hahn should she need to bribe the guards at the border. With the help of Niels Bohr, a Nobelist who was also Jewish and who aided many refugees of the Nazi regime, Meitner obtained a laboratory and continued her researches, culminating in the first clear description of nuclear fission of uranium. (Meitner, Hahn, and Bohr all have elements named for them on the Periodic table.)
And then there is Edward Teller, the “father of the hydrogen bomb”. Teller, like Szilard, was an Austro-Hungarian Jew who spent a great deal of his productive career at German universities. (In those days German universities were among the most well-funded and important, so Germany tended to attract the brightest minds from poorer, less stable European countries such as Hungary, Poland, and Russia. Hitler reversed this, and it may have been one of his most critical errors.) Teller fled Germany in 1933 and would eventually end up at Los Alamos as a key scientist in the Manhattan Project. Teller was joined at Los Alamos by Felix Bloch, the Swiss-born Jewish physicist who left Germany in 1933 and whose U.S.-based work would lead to the development of magnetic resonance imaging, Emilio Segre (who discovered anti-protons and left Italy in 1938) who contributed to the development of plutonium-based bombs, and Hans Bethe (who left Germany in 1933 and who developed the concept of the critical mass for a nuclear chain reaction).
Other Nobelists in Physics who fled Central Europe were Otto Stern (a Polish-born physicist who left Hamburg in 1933), Wolfgang Pauli (a brilliant contributor to quantum physics, whose best work was behind him when he left Europe in 1940 after failing to obtain Swiss citizenship), Max Born (another founder of quantum mechanics who left Germany for Britain in 1933), and Dennis Gabor (a Hungarian-born Jew who fled Germany in 1933 and would later invent holography). Walter Kohn, whose prize was in chemistry, fled Germany with his family before he became a scientist, but would go on to win a Nobel Prize for work that shaped our understanding of current flow.
Hitler’s prejudice against the Jews was not merely a boon to the war efforts of the United States (since so many scientists fled there either at first or eventually), but also was a loss to the war efforts of Germany. For example, another Nobel Prize winner, the German Jew Gustav Ludwig Hertz, fled Germany in 1934 and eventually participated in the nuclear program of the Soviet Union. Hertz, interestingly, was a Lutheran, but had a grandfather who was once Jewish.
In just physics and chemistry alone, the list of people who were Jewish, trained or worked in Germany or in areas threatened by Germany, and who then fled for the Soviet Union, Great Britain, or United States is incredibly impressive.
Germany and Italy were also a leaders in the biological sciences. I had already been familiar with the story of one of my scientific heroes, Rita Levi-Montalcini, who received her Nobel Prize for the discovery and analysis of nerve growth factor, and who could therefore be counted as a founder of developmental neurobiology. (She died earlier this year at the age of 103.)
Levi-Montalcini, already one of the few Italian women pursuing a scientific career, was stripped of her position in 1938 when the Fascists solidified their alliance with Germany by passing their own “race” laws. Even denied a laboratory, Levi-Montalcini obtained fertilized eggs from local chicken farmers (an unusual request then as it would be today) and studied the development of the chicks inside their carefully thinned or opened shells in her home. In Levi-Montalcini’s case her emigration to the United States did not occur until after the war, when Viktor Hamburger (an eminent biologist based in St. Louis who had studied in the United States and decided to stay because, you guessed it, he was a German-born Jew) invited her to join his laboratory to work out which of their competing ideas was correct about limb innervation. Levi-Montalcini accepted, proved to be correct, won a Nobel Prize in 1986, and, though she would eventually return to Italy, contributed to the United States becoming the new nexus of neurobiological research.
(By the way, Hamburger lived to be 100 years old himself. I’m not sure what chemicals they were handling in that laboratory, but I want some. Stanley Cohen, Levi-Montalcini’s Nobel co-awardee who determined nerve growth factor’s chemical structure, still lives at age 90.)
If Levi-Montalcini was a founder of developmental neurobiology, Otto Loewi would have to rank as a founder of neuropharmacology. In 1920, Loewi conducted an experiment celebrated both for its elegance and for the fact that it came to him one night in a dream. He woke from the dream, went back to sleep, and couldn’t remember it the next morning, but he fortunately had the same thought the next night and, rather than trust his memory, went straight to the lab. Loewi stimulated the vagus nerve of a frog, took note of the fact that the frog’s heart (as expected) slowed its rate of beating. He then collected the fluid surrounding the heart, applied it to a second frog’s heart, and noted the same deceleration. At once he demonstrated that neurons release chemicals that transmit messages – chemicals that would soon be called “neurotransmitters” and which would revolutionize neurobiology and medicine.
In 1938, the Germans tossed the Austrian-born Jew out of his laboratory, confiscated his possessions and his research notes, and sent him away. Loewi fled to the United States.
Bernard Katz fled Germany in 1935. It is difficult to understate Katz’s importance to the development of our understanding of neurotransmission. He spent a career making fundamental discoveries. Katz’s early work with Alan Hodgkin led to the Nobel Prize-winning model of the resting potential of neurons and the action potential of signal transmission elucidated by Hodgkin and Andrew Huxley. With his later work demonstrating the role of calcium currents in the quantal release of neurotransmitters and their function in generating post-synaptic potentials, Katz probably did more than any one person in taking Loewi’s initial insight to a modern and thorough understanding of the synapse.
Other Nobelists in Physiology or Medicine that fled central Europe were Otto Meyerhof (who studied glycolysis in muscle and fled in 1938 near the end of an illustrious career), Ernst Chain (a German Jew who fled in 1933 to Britain and would discover the therapeutic effects of penicillin), Hans Krebs (whose Krebs cycle is a triumph of biochemistry and a central fact in physiology – he fled Germany in 1933 despite having served in the German army and despite carrying the perhaps unfortunate middle name “Adolf”), Salvador Luria (an Italian microbiologist who was a founder of virology and who earned a well-timed fellowship in 1938 to study in the United States; like Levi-Montalcini, he turned this into a very extended stay), and Andrew Schally (a brilliant endrocrinologist who lived a harrowing life during World War II after the Germans invaded his native Poland).
The list of biologists whose careers were disrupted – or spurred on – by the racial persecution of Adolf Hitler and, to a lesser extent, Benito Mussolini, is nearly as impressive as the list of physicists and chemists. The names include scientists who were seminal in the founding of sciences, or subdisciplines of sciences, that shape modern technology, medicine, and philosophy. Quantum mechanics, nuclear chemistry, virology, developmental neurobiology, neuropharmacology, neuroendocrinology – the genesis and maturation of each of these fields intersected with the bizarre and horrifying geopolitics of central Europe in the period after World War I.
On one hand there is a sense that everything worked out okay. Lise Meitner and Leo Szilard got out, Albert Einstein wrote a famous letter to President Roosevelt, and Edward Teller and Felix Bloch ensured that the “good guys” had the biggest weapons and the bad guys didn’t. But who knows? The atomic bomb was developed and used – not against Hitler and Mussolini, but against a Japanese Empire perhaps on the brink of surrender. Theoretical physics and neuroscience continue to flourish, and while magnificent research continues to be conducted in Germany and other areas of Central Europe, one wonders how disruptive the war and its aftermath may have been on the biological and physical sciences in Europe. And while we can wonder at the good fortune of a young man like Walter Kohn getting out at the right time, and growing up to become a great scientist, we should also pause and consider how many of Kohn’s peers might not have been so fortunate.