By SAURABH JHA and JEANNE ELKIN
Mr. Smith’s pneumonia was clinically shy. He didn’t have a fever. His white blood cells hadn’t increased. The only sign of an infection, other than his cough, was that his lung wasn’t as dark as it should be on the radiograph. The radiologist, taught to see, noticed that the normally crisp border between the heart and the lung was blurred like ink smudged on blotting paper. Something that had colonized the lungs was stopping the x-rays.
Hundred and twenty-five years ago, Wilhelm Conrad Roentgen, a German physicist and the Rector at the University of Wurzburg, made an accidental discovery by seeing something he wasn’t watching. Roentgen was studying cathode rays – invisible forces created by electricity. Using a Crookes tube, a pear-shaped vacuum glass tube with a pair of electrodes, Roentgen would fire the cathode rays from one end by an electric jolt. At the other end, the rays would leave the tube through a small hole, and generate colorful light on striking fluorescent material placed near the tube.
By then photography and fluorescence had captured literary and scientific imagination. In Arthur Conan Doyle’s Hound of the Baskervilles, the fire-breathing dog’s jaw had been drenched in phosphorus by its owner. Electricity and magnetism were the new forces. Physicists were experimenting in the backwaters of the electromagnetic spectrum without knowing where they were.
On November 8th, 1895, when after supper Roentgen went to his laboratory for routine experiments, something else caught Roentgen’s eyes. Roentgen closed the curtains. He wanted his pupils maximally dilated to spot tiny flickers of light. When he turned the voltage on the Crookes tube, he noticed that a paper soaked in barium platinocyanide on a bench nine feet away flickered. Cathode rays traveled only a few centimeters. Also, he had covered the tube with heavy