But the usefulness of this new technology was readily apparent, and X-ray facilities were rapidly set up around the world for medical use – to detect fractures, find foreign bodies, gallstones, etc. By the end of 1896, more than a thousand scientific articles on X-rays had appeared. The response to Roentgen’s rays, indeed, was not only medical and scientific, but seized the public imagination in various ways. One could buy, for a dollar or two, an X-ray photograph of a nine-week-old infant ‘showing with beautiful detail the bones of the skeleton, the stage of ossification, the location of the liver, stomach, heart, etc.’
X-rays, it was felt, might have the power to penetrate the most intimate, hidden, secret parts of people’s lives. Schizophrenics felt that their minds could be read or influenced by X-rays; others felt that nothing was safe. ‘You can see other people’s bones with the naked eye’, thundered one editorial, ‘and also through eight inches of solid wood. On the revolting indecency of this there is no need to dwell.’ Lead-lined underclothes were put on sale to shield people’s private parts from the all-seeing rays. A ditty appeared in the journal Photography, ending,
My uncle Yitzchak, after being in practice with my father during the months of the great flu epidemic, had been drawn into the practice of radiology soon after the First World War. He had gone on, my father told me, to gain uncanny powers of diagnosis by X-ray, able almost unconsciously to pick up the smallest hints of any pathological process.
In his consulting rooms, which I visited a few times, Uncle Yitzchak showed me something of his apparatus and its uses. The X-ray tube in his machine was no longer visible, as it had been in the early machines, but was housed in a beaked and humped black metal box – it looked rather dangerous and predatory, like the head of a giant bird. Uncle Yitzchak took me into the darkroom to watch him develop an X-ray he had just taken. Dimly, in the red light, translucent almost, beautiful, I saw the outlines of a thighbone, a femur, on the large film. Uncle pointed out to me a tiny hairline fracture, just visible as a grey line.
‘You’ve seen X-ray screening’, said Uncle Yitzchak, ‘in shoe shops, which show you the bones moving through the flesh.[57] We can also use special contrast media to show us some of the other tissues in the body – it’s marvelous!’
Uncle Yitzchak asked if I would like to watch this. ‘You remember Mr. Spiegelman, the mechanic? Your father suspects that he has a stomach ulcer, and sent him to me to find out. He’s going to have a barium ‘meal.’
‘We use barium sulphate’, Uncle continued, stirring up the heavy white paste, ‘because barium ions are heavy and almost opaque to X-rays.’ This comment intrigued me and made me wonder why one could not use even heavier ions instead. One could have, perhaps, a lead, or mercury, or thallium ‘meal’ – all of these had exceptionally heavy ions, though, of course, the meals would be lethal. A gold or platinum meal would be fun, but far too expensive. ‘What about a tungsten meal?’ I suggested. ‘Tungsten atoms are heavier than barium, and tungsten is neither toxic nor expensive.’
We entered the examining room, and Uncle introduced me to Mr. Spiegelman – he remembered me from one of our Sunday morning rounds. ‘This is Dr. Sacks’s youngest, Oliver – he wants to be a scientist!’ Uncle positioned Mr. Spiegelman between the X-ray machine and a fluorescent screen and gave him the barium meal to eat. Mr. Spiegelman spooned the paste down, grimacing, and started to swallow it, as we watched on the screen. As the barium passed down the throat and into the esophagus, I could see this filling and writhing, slowly, as it pushed the bolus of barium into the stomach. I could see, more faintly, a ghostlike background, the lungs expanding and contracting with each breath. Most disconcerting of all, I could see a sort of bag, pulsing – that, Uncle said, pointing, was the heart.
I had sometimes wondered what it would be like to have other senses. My mother had told me that bats used ultrasound, that insects saw ultraviolet, that rattlesnakes could sense infrared. But now, watching Mr. Spiegelman’s innards exposed to the X-ray ‘eye’, I was glad that I did not have X-ray vision myself, and that I was confined, by nature, to a small part of the spectrum.
Like Uncle Dave, Uncle Yitzchak retained a strong interest in the theoretical foundations of his subject and its historical development, and he also had a little ‘museum’, in this case of old X-ray and cathode-ray tubes, going back to the fragile, three-pronged ones that had been used in the 1890s. The early tubes, Yitzchak said, offered no protection against stray radiation, nor were the dangers of radiation fully realized in the early days. And yet, he added, X-rays had shown their dangers from the start: skin burns were seen within months of their introduction, and Lord Lister himself, the discoverer of antisepsis, issued a warning as early as 1896 – but it was a warning that no one heeded.[58]
It was also apparent from the start that X-rays carried a good deal of energy and would generate heat wherever they were absorbed. Yet, penetrating as they were, X-rays did not have too great a range in air. It was the opposite with wireless waves, radio waves, which, if properly projected, could leap across the Channel with the speed of light. These, too, carried energy. I wondered whether these strange, sometimes dangerous relatives of visible light had perhaps suggested to H.G. Wells the sinister heat ray used by the Martians in The War of the Worlds, published only two years after Roentgen’s discovery. The Martian heat ray, Wells wrote, was ‘the ghost of a beam of light’, ‘an invisible yet intensely heated finger’, ‘an invisible, inevitable sword of heat.’ Projected by a parabolic mirror, it would soften iron, melt glass, make lead run like water, make water explode incontinently into steam. And its passage across the countryside, Wells added, was ‘as swift as the passage of light.’
While X-rays took off, engendering innumerable practical applications and perhaps an equal number of fantasies, they elicited a very different train of thought in the mind of Henri Becquerel. Becquerel was already distinguished in many fields of optical research, and came from a family in which a passionate interest in luminescence had been central for sixty years.[59] He was intrigued when he heard in early 1896 the first news of Roentgen’s X-rays and the fact that they seemed to be emanating not from the cathode itself but from the fluorescent spot where the cathode rays hit the end of the vacuum tube. He wondered whether the invisible X-rays might not be a special form of energy that went along with the visible phosphorescence – and whether indeed all phosphorescence might be accompanied by the emission of X-rays.
Since no substances fluoresced more brilliantly than uranium salts, Becquerel pulled out a specimen of a uranium salt, potassium uranyl sulphate, exposed it to the sun for several hours, and then laid it on a photographic plate wrapped in black paper. He was greatly excited to find that the plate was darkened by the uranium salt, even through the paper, just as with X-rays, and that a ‘radiograph’ of a coin could be easily obtained.
Becquerel wanted to repeat his experiment, but (this was the middle of the Parisian winter and the sky remained overcast) he was unable to expose the uranium salt to the sun, so it lay undisturbed in the drawer for a week, on top of the black-wrapped photographic plate, with a small copper cross in between. But then, for some reason – was it an accident, or a premonition? – he developed the photographic plate anyway. It was darkened as strongly as if the uranium had been exposed to sunlight, indeed more so, and showed a clear silhouette of the copper cross.
57
Shoe shops everywhere in my boyhood were equipped with X-ray machines, fluoroscopes, so that one could see how the bones of one’s feet were fitting in new shoes. I loved these machines, for one could wiggle one’s toes and see the many separate bones in the foot moving in unison, in their almost transparent envelope of flesh.
58
Dentists were especially at risk, holding small X-ray films inside their patients’ mouths, often for minutes at a time, for the original emulsions were very slow. Many dentists lost fingers by exposing their hands to X-rays in this way.
59
Henri Becquerel’s grandfather, Antoine Edmond Becquerel, had launched the systematic study of phosphorescence in the 1830s and published the first pictures of phosphorescent spectra. Antoine’s son, Alexandre-Edmond, had assisted in his father’s research and invented a ‘phosphoroscope,’ which allowed him to measure fluorescences that lasted as briefly as a thousandth of a second. His 1867 book,