There followed an outpouring of professional admiration. The University of Wuerzburg conferred on Roentgen its most exalted honor, naming him rector of the university. The students held a celebratory torchlight parade, insisting the notoriously shy professor regale them with a speech. He received various national medals and opportunities to lecture around the world. In 1901, Roentgen was awarded the first Nobel Prize for physics. His discovery spawned the entirely new field of medical imaging, or diagnostic radiology, with all of its subsequent developments—ultrasonography, computed tomography, magnetic resonance imaging, and nuclear medicine—traceable to that single instant of recognition in 1895.
Within months of Roentgen’s discovery, X-rays found their principal application in medicine. In Glasgow, Dr. John McIntyre showed the potential of medical imaging to demonstrate the presence of kidney stones and swallowed foreign objects. His work was emulated at the Dartmouth Infirmary in the United States by Dr. Edwin Frost, who showed the advantages of roentgenographic imaging in diagnosing broken bones. The Roentgen rays found extensive medical applications during the Boer War and in World War I. Marie Curie famously spent the money she received with her second Nobel Prize on a mobile X-ray machine that she drove along the front lines, exposing radiographs to improve the treatment of wounded soldiers.
X-ray frenzy extended beyond medical applications. Before it was recognized that overlong and repetitive exposure to X-radiation was acutely injurious and, with excessive exposure, might induce cancer in the long term, entrepreneurs seeking to capitalize on Roentgen’s discovery employed X-rays in new consumer products and even entertainment. Pitchmen ballyhooed harmless but ineffectual home remedies containing fluids they said had been exposed to X-rays as curative for everyday ills like headaches and constipation. Fears developed that the dissemination of X-ray apparatuses would infringe on personal privacy. There were rumors that X-rays would allow the unscrupulous to see through women’s clothing, prompting one company to quite profitably sell a line of X-ray-proof garments. A bit of doggerel played upon this conceit:
For now-a-days I hear they’ll gaze,
Through cloak and gown and even stays,
Those naughty, naughty Roentgen Rays.
As Roentgen’s popularity grew, Lenard stewed from the sidelines. Lenard eventually received his Nobel Prize in 1905 for the work he’d done with high-energy vacuum tubes, but that did not reverse the public perception. The press glorified Roentgen, while the name “Lenard” hardly bore mention. He had missed the big discovery and received short shrift. Despite his having done the work that had made possible the discovery of the X-ray, next to Roentgen, he was comparatively an unknown.
Lenard’s experience with Roentgen presaged his attacks on Einstein by a quarter of a century. How unfair! It had been his contributions that underlay everything that Roentgen had described. Roentgen had been lucky; his discovery was simply the logical next step to the groundwork Lenard had laid. Lenard didn’t fault a giddy and naïve public. It wasn’t their fault that they were ignorant of the complete story. It was Roentgen. Why hadn’t Roentgen set the record straight by giving him credit as a full partner, for being the one who had enabled his observations?
Lenard’s relationship with Roentgen, as with Einstein, began benignly, even with admiration. In an early letter written by Roentgen to Lenard in 1894, Roentgen expressed a desire to acquire some of the aluminum windows that Lenard was using on his eponymous tube. Lenard answered apologetically that the machinist he was using was having trouble enough supplying his own needs, but nonetheless, “I permit myself to send you two sheets from my supply.”
Three years after Roentgen announced his discovery, Lenard wrote him a letter, declaring, “I was particularly happy to know for sure what I had never had reason to doubt, that you are friendly toward me. I was often afraid it could have been otherwise, and I would have been sorry for that.” Absolving himself from any “polemics” that may have come to Roentgen’s attention, Lenard continued, “Because your remarkable discovery caused such remarkable attention in the farthest circles, my modest work also has come into the limelight, which was of particular luck to me, and I am doubly glad to have had your friendly participation, especially through the presence of the x-ray discovered by you [italics mine].” He acknowledged that he had erred by presuming the observed effects were due to cathode rays rather than X-rays. By giving Roentgen credit for the initial discovery, Lenard provided history with a literal smoking gun that went against Lenard’s later assertions that he was the discoverer of X-rays.
For his part, Roentgen portrayed a similar tone of collegiality and respect. A letter to Lenard written in April 1897 expressed disappointment at his not being in Wuerzburg to receive Lenard when the younger man unexpectedly came to visit. “I hope there will soon be another opportunity,” Roentgen wrote. “For the receipt of prizes and medals we several times have had reason for mutual congratulations. . . . Be assured that I am very happy that my work has found such a ready recognition from you.”
Roentgen further apologized for “untimely newspaper articles” written by a former assistant and close friend, Ludwig Zehnder, whom he had known since his days as a student. He had complained in a letter to Zehnder about rumors to the effect that it was not he, Roentgen, who had discovered the X-ray but an assistant or diener. He now wrote Lenard that he had mentioned Lenard’s name only in passing and that he was “innocent as a newborn child and furious about it.”
Curiously, while Roentgen’s will ordered the destruction of his papers after his death in 1923, he insisted that his correspondence with Lenard be preserved in a safe at the University of Wuerzburg, presumably over concerns about the younger man’s claims to the historical provenance of X-rays. It was well that he did. During the 1930s, the years of Lenard’s greatest influence with the Nazi hierarchy, fears arose among Roentgen’s Wuerzburg colleagues that pro-Lenard elements might seek to destroy the letters. Authorities at the Institute made photocopies and sent them to sympathetic scientists in other locales for safekeeping.
Their caution was well founded. As Lenard’s political star ascended, he became more assertive in his claims of primacy regarding the discovery of X-rays. The scientific establishment of the Third Reich sought to revise the history surrounding the events of 1895. In 1935, an article by Johannes Stark concluded that Roentgen had done little that was original. Rather, he had merely followed in the footsteps of Lenard. Assistant professor Friedrich Schmidt, working under Stark, who by then had become president of Berlin’s powerful Reich Physical and Technical Institute, also sided with Lenard. He concluded that despite a lack of physical evidence, Lenard had made notes indicative of his having recognized X-rays for what they were prior to Roentgen’s first publication.
Roentgen believed that his receiving the Nobel Prize for discovering X-rays precipitated Lenard’s envy, but there may have been multiple factors at work. Given his suspicious nature, Lenard may well have held a grudge over Roentgen’s letter to Zehnder, believing that, despite his disclaimer, Roentgen had written negative comments about him that later found their way into the public sphere. Even more critically, as was evident with his envy of Einstein’s accolades, he almost certainly made resentful comparisons between Roentgen’s public acclaim and his own. Even his own Nobel Prize failed to salve the hurt he felt over the recognition accorded Roentgen. He belittled Roentgen’s contributions in his Nobel Lecture and took the position that “anyone who was wide awake and using a Lenard tube could have discovered the X-rays.”
If Lenard’s claims of primacy depend on Roentgen having used a Lenard tube that evening in 1895 when he intuited X-rays, then they lack supporting evidence. The type of tube Roentgen was using when he made the leap from observation to discovery is unknown. An investigation of purchasing records shows that the University of Wuerzburg Institute of Physics bought only one Lenard tube in 1895, but at the same time acquired a number of Hittorf and Crookes tubes. The type of tube Roentgen employed the n
ight of November 8, 1895, remains a point of contention.
Given Lenard’s statements concerning the inevitability of Roentgen’s discovery, why didn’t he discover X-rays? According to Lenard’s laboratory workbooks, it appears he had, on occasion, observed what he believed to be cathode rays causing imprints on photographic plates. He also had witnessed plates fluorescing at distances greater than would be expected of cathode rays and after traversing objects that would have been expected to stop their less energetic passage.
Lenard gave four reasons why he missed out on being the discoverer of X-rays, three of which were parroted by Stark in a 1935 publication when Stark and Lenard were at the peak of their influence. That the items are worded nearly identically suggests that Lenard colluded with Stark in making his own case:
During that period when he was serving a sequence of temporary appointments, he had changed institutions so frequently that he had not had the time to settle in and conduct his experiments as he would have liked;
At the time, he was using a tube encased in tin to exclude light emissions, rather than the cardboard used by Roentgen; the tin might have absorbed more of the X-rays, thus reducing their intensity;
He was at the mercy of Professor Hertz. The professor preferred he use a cheaper substance—keton (pentadecylparatolylketon), rather than barium platinocyanide—for his investigations. In fact, experiments conducted by Roentgen validated the seriousness of this shortcoming. Roentgen found that although keton fluoresced remarkably well under the bombardment of cathode rays, the material was wholly unresponsive to X-rays;
His cathode ray tube was poorly made by the glassblower, Louis Mueller-Unkel, whereas Roentgen’s tube had been made perfectly. In this regard, Lenard again blamed Hertz for his stinginess. Lenard wrote in his autobiography that he had approached his professor about purchasing a better tube. While Hertz had not said “no” outright, he clearly was unconvinced, telling the young man to go forward with the purchase only if he felt that the new tube would truly be worth the expense.
These last two explanations require further scrutiny. The half-Jew Hertz had prevented him from having been the first to observe X-rays and reap the recognition that had been accorded Roentgen. On the other hand, despite Hertz’s racial heritage, his story, at least, is included among Lenard’s summaries in his book about the lives and scientific works of “great men.” The biographies of neither Roentgen nor Einstein are among the sixty-one selected.
As Hitler’s chief scientific advisor, Lenard remained a powerful force in German academic politics and among the scientists of the Third Reich long after his 1933 retirement from his directorship of the University of Heidelberg Institute of Physics. To insinuate doubt about the authenticity of Roentgen’s claims, he repeatedly raised the question: why had Roentgen insisted on his executors burning his research notebooks and other papers upon his death? Subsequent articles in Nazi periodicals like Voelkischer Beobachter and Das Schwarze Korps—the weekly publication of the SS—beat the drum for official recognition of Lenard as the discoverer of X-rays until the Reich happily complied.
The Nazis did their best to eradicate the memory of Roentgen’s work and replace it with an ersatz history that lauded one of their own. In 1944, the same Physical and Medical Society of Wuerzburg, before whom Roentgen first presented his discovery, made application to the Minister of the Reichspost (the German postal service), Wilhelm Ohnesorge, requesting that the Reich design a stamp honoring the fiftieth anniversary of Roentgen’s discovery. Ohnesorge was coincidentally a physicist who had trained under Lenard. The request was denied.
In 1945, as American troops advanced toward Berlin during the final days of World War II, Lenard fled Heidelberg. Along with Stark, he had been one of the point men involved in enforcing laws forbidding the employment of Jews in German universities. He was certain that those charged with seeking out and detaining Nazi war criminals would be on the lookout for him. Surprisingly to Lenard, they either were not looking for him or were oblivious of his whereabouts. He remained at large for nearly two months in the tiny Badensian farming village of Messelhausen before turning himself in to authorities and being placed under house arrest.
A little more than a month later, Lieutenant Colonel Lewis E. Etter, an American physician of the U.S. Army Medical Reserve Corps, sat in the anteroom of Lenard’s cottage. Doctor Etter had requested and been given permission through military channels to conduct two interviews of Philipp Lenard about his relationship with Wilhelm Conrad Roentgen, the man credited everywhere except Nazi Germany with discovering X-rays. Lenard’s claims to the contrary had come up during a trip to Roentgen’s laboratory in Wuerzburg, earlier in the year. Etter’s interest in Lenard was academic. While stationed in England, early in the war, he had made an extensive study of radiation physics. Later, he served as chief of radiology at several military medical installations in Europe. He was only months away from resuming his civilian life as a neuroradiology fellow and an instructor in radiology at the University of Pittsburgh. In time, Etter would become a leading expert on the radiographic anatomy of the skull.
On September 20, 1945, Etter sat enveloped in an overstuffed chair beside a dark wood table, lamplight reflecting from its oiled sheen. Only a moment earlier, he had closed the thick volume lying beside him. From his first interview of Lenard two weeks earlier and after reading parts of Lenard’s Deutsche Physik, which the aged scientist had suggested he borrow from a local physician, Etter had learned the essence of the old man’s dispute with Roentgen. He’d found a handwritten note, signed by Lenard, on the flyleaf of the book:
To be found in this volume, my reckoning with Roentgen, held back for almost fifty years. . . . Again, I speak now only because of my ineradicable desire for truth. For fifty long years one was so dull as never to care seriously about the actual coming about of a rather much noticed and practically used discovery.
Having familiarized himself with the history that lay between the two men, Etter felt that he had prepared himself as much as possible. He’d read the passages he’d found cited in Lenard’s note and felt that he now understood Lenard’s point of view. He’d also read and reread a footnote he’d found well into the text: “A comparison can best make clear to the neutral observer Roentgen’s role in the discovery,” Lenard wrote. He went on,
I shall make this striking comparison here because it may throw a light on the even now widespread historical confusion and untruth! Roentgen was the midwife at the birth of the discovery. This helper had the good fortune to be able to present the child first. She can only be confused with the mother by the uninformed who knows as little about the procedure of the discovery and the preceding facts as children of the stork.
Etter reopened Lenard’s book and took another glance at the flyleaf. From his first interview of Lenard, it was clear that Lenard’s position on the discovery of X-rays was unchanged. On that occasion, he had expressed the same birthing metaphor as he had written but even more directly. He was the true “mother of the X-rays.” Lenard’s work had guided Roentgen to the point that “All Roentgen had to do was push a button, since all the groundwork had been prepared by me. . . . Without my help, the discovery of X-rays would not have been possible even today. Without me, the name of Roentgen would be unknown.”
The second interview continued for some time in the same vein. Lenard was in high spirits at the interest the American soldier showed in his life. They were covering well-trod ground when Lenard made an additional claim. Speaking of the history of cathode ray tubes, he credited Hittorf with the initial invention, then added, “But nothing of great importance was added to it until my work twenty-five years later. I was always too modest and did not rush into print. In my letter to Roentgen, where I praised him for his great discovery [the letter of May 21, 1897], I thought he would reply that he really owed it all to me and my tube, but I waited for this acknowledgement from him in vain.”
Etter was stunned. He recognized in that instant that this was the
main source of Lenard’s resentment for Roentgen—not that Roentgen had scooped him on the discovery but that he felt slighted by not having been invited to share the glory. Was this all of what had motivated Lenard’s long crusade to minimize Roentgen’s achievement? Or was there something even more nefarious? Etter was well aware that Lenard had had a hand in war crimes against Jewish academics. He had read something of Lenard’s rambling polemic detailing his beliefs concerning the degeneracy of the Jewish race in his introduction to Deutsche Physik. Etter wondered if there might also be an element of anti-Semitism involved in his perception of Roentgen. He asked the question directly, “Was Roentgen a Jew?”
Lenard replied, “No, but he was a friend of Jews and acted like one.”
There was little more to say. As Etter stood to leave, Lenard asked that the Lieutenant Colonel wait just a moment and left the room. He returned a couple of minutes later and formally presented Etter with a photographic portrait of himself taken three years previously on his eightieth birthday. It had been a marvelous day for Lenard, immensely brightened by a personal congratulatory communication from Adolf Hitler. The portrait depicted Lenard in formal attire, his chin lifted proudly, his eyes gazing skyward. On the back of the photograph, Lenard had inscribed, “Dr. Etter, the representative of the conqueror, with thanks for his scientific interest. 20 Sept. 45,” and signed it “P. Lenard.”
The Man Who Stalked Einstein Page 9