On the evening of November 8, 1895, Wilhem Conrad Röntgen was working in his laboratory at the University of Würzburg in Germany when he made a peculiar discovery. While studying how cathode ray tubes emit light, Röntgen was distracted by a glowing fluorescent screen that he thought was too far away from the tube to be affected by cathode rays. He spent the next six weeks cooped up in his lab to understand what was making the screen glow. His discovery would change the world. Penetrative rays Röntgen found that the impact of cathode rays on the glass vacuum tube was generating a “new kind of invisible ray” with extraordinary penetrative power, which could be recorded on photographic plates. He placed all kinds of material — from paper and cardboard to wood, copper, and aluminium — between the cathode ray tube and the screen, and observed that these invisible rays still made it to the screen behind, albeit to differing degrees. Then he wondered, if these rays could pass through even metal, what about flesh? Three days before Christmas, Röntgen carried out an experiment which foreshadowed the most popular use case of his discovery. He called his wife to the laboratory, and emerged with a ghoulish photograph of the bones in her hand and the ring on her finger. Over Christmas, he wrote a ten-page article titled “On a new kind of rays”, which was accepted by the Proceedings of the Würzburg Physical-Medical Society on December 28. In it he named his discovery “X-radiation” (x-ray for short) after the mathematical term ‘X’ which denotes something unknown. A global sensation On January 5, an article detailing the discovery was published on the front page of leading Austrian daily Die Presse under the headline “A sensational discovery”. It said: “If we let our fantasies run freely… this could be of immeasurable help for the diagnosis of countless diseases.” The British press picked up the story a day later — and by the end of the week, Röntgen was a global celebrity. On January 13, he was awarded the Prussian Order of the Crown, Second Class by the Kaiser. On January 16 his name appeared on the front page of The New-York Times (the hyphen was dropped later that year). “Emperor William had Prof. Roentgen to rush from Würzburg to Potsdam to give an illustrated lecture to the royal family on his alleged discovery of how to photograph the invisible,” the article said. Around the world, Röntgen’s discovery enthused physicians who almost immediately began to use x-rays for diagnostic purposes. British physician Major John Hall-Edwards became the first to use them to guide a surgery on February 14, 1896. And when the British Army launched its Nile expedition in the summer of 1896, it took to Egypt two x-ray machines to be used to locate bullet wounds and diagnose bone fractures. But the discovery’s virality invited the interest of gossip- and fear-mongers around the world. In an 1896 issue of Photography magazine, a writer named Wilhelmina penned the poem “X-actly So!” with the lines: “I hear they’ll gaze. Thro’ cloak and gown — and even stays. These naughty, naughty, Roentgen Rays.” One opportunistic London company even advertised “X-ray proof underclothing — especially for the sensitive woman” in the journal Electrical World. And a group of concerned New York citizens considered legislation against the use of x-rays in opera glasses. Röntgen’s legacy Röntgen’s rays changed the world. Physicians readily took to it, and soon x-ray machines were everywhere. During the 1930s and 1940s, they were so ubiquitous that some shoe stores in Europe even offered free x-rays for customers to see the bones of their feet (what actual benefit this provided is questionable beyond looking cool). During this time, there was little concern for the potential side effects of x-rays. That is because even after their discovery, x-rays were not understood particularly well. It was in 1912-13 that physicist Max von Laue showed that x-rays were diffracted by crystals — just like visible light. He won the Nobel in Physics for this discovery. His students would later confirm that x-rays are a type of electromagnetic radiation which has a higher frequency than visible light. Although the earliest anecdotes regarding the harmful effects of x-rays can be dated to the end of the nineteenth century, it took decades for scientists to fully understand — and minimise — the risks of radiation exposure from x-rays. Today, x-rays continue to be the cornerstone of diagnostic medicine. Furthermore, the discovery of x-rays and the consequent birth of the discipline of radiology paved the way for the development of a wide range of imaging techniques such as magnetic resonance imaging (MRI), computed tomography (CT), ultrasound, and echocardiography, which are a part and parcel of a modern physicians toolkit.
