Museum of Atomic perMutation

Clarence Dally (1865-1904), assistant to industrialist Thomas Alva Edison. The first recognized American X ray fatality.

Soon after the discovery of X rays in 1895, both men repeatedly exposed themselves to x rays in popular demonstrations and investigations of the exotic new imaging technology. Mr. Dally tested his X ray equipment on his own hands.

X ray "burns" on his hands turned cancerous. The cancer spread throughout his body and was ultimately fatal despite many efforts to cut out or otherwise treat the disease.

Thomas Edison and Clarence Dally

The discovery of x radiation blew everybody's mind; it was totally unexpected. Thomas Edison jumped right in and tried to exploit this unprecedented power to see inside solid bodies. He underestimated his ignorance, fatally. Of course, no one knew what effects the new rays could have on the human body. Fortunately for Edison, his blunder only caused him permanent persistent discomfort.
His main x-ray technician, Clarence Dally, who worked closely and consistently with the newly devised apparatii, was not so lucky. As we know now, you can absorb a large amount of X rays without any immediately visible signs. If the dose is spread out over a long enough period (say over days or weeks rather than minutes or seconds) you could conceivably take enough to kill you without feeling it. Eventually, like so many other unwitting "pioneers" who spent their lives on the new and magical X rays, Dally noticed what's euphemistically known as X ray "burn". By the time the burns showed up the damage was already potentially fatal in the years to come. Dally didn't stop even as his condition grew worse. He even kept working at the infernal machine when he knew his hands were cancerous. I won't go into the gruesome details, but he wouldn't stop and neither did the cancer.


"The ultimate danger of x-ray exposure was ... dramatically brought to light by the deaths of many early radiologic pioneers. Clarence Dally, Edison's chief assistant, was the first U.S. Roentgen ray fatality. Mr. Dally's intimate work with various aspects of x-ray tube production had led to numerous instances of radiation 'burn'. Yet with time off these lesions of the face, fingers, and hands would subside and he would return to the West Orange, New Jersey laboratory. By 1902 the 'burns' were refractory to treatment; ulceration and pain became worse; skin grafts failed; and carcinoma was noted at the base of one of the skin lesions. Subsequent operations included amputations of both arms, but mediastinal involvement led to Mr. Dally's death in 1904. Edison was devastated and halted x-ray investigations at his facilities."

The Terrible Power Of The Rays:
"It was not until the death of Clarence Dally (1865-1904), Edison's assistant in the manufacture of X-ray apparatus, and the documentation of his struggle with burns, serial amputations, and extensive lymph node involvement, that medical observers took seriously the notion that the rays could prove fatal. Even then it was difficult to believe in a direct carcinogenic effect from X rays."

Figures in Radiation History: Thomas Alva Edison
"During the course of these investigations, Clarence Dally, one of Edison's most dependable assistants, developed a degenerative skin disorder which progressed into a carcinoma. In 1904, Dally succumbed to his injuries - the first radiation related death in the United States. Immediately, Edison halted all his X-ray research noting 'the X rays had affected poisonously my assistant, Mr. Dally...' "

Diagnostic imaging: Finding new ways to see; seeing new ways to cure
"Edison abandoned the new field of radiology quickly, however, when he recognized the risks involved. His assistant, Clarence Dally, began having health problems shortly after first experimenting with x-rays. Eventually Dally lost both arms to malignant ulceration. He died a painful and horrible death in 1904 and is remembered as the first martyr to radiation. Edison was haunted by Dally's death and adamantly refused to be x-rayed throughout the rest of his 84-year life."

From Books:
"Mr. Edison's injuries are interesting. His left eye is out of focus, his digestion is upset, and lumps have formed all through the region of his stomach."
-Journal of American Medical Association 41(22 August 1903): 499-500. Quoted by Lisa Cartwright in Screening the Body: Tracing Medicine's Visual Culture (Minneapolis, MN: University of Minnesota Press,1995): 109.

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Museum of Atomic perMutation

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last update: December 1998
* The Museum of Atomic perMutation * is a by-product of NUKEVILLE