Electric Shows, X-Ray Shows, Scientific Demonstrations, etc.
In the age when the electric light bulb had recently been invented (1879) and the mysterious invisible X-ray had emerged (1876) you could make a show demonstrating the miraculous and weirdness of these new technologies.
Thus was born the Electric Show, and much rarer and dangerous, X-Ray Show.
The tradition of course was much older than the late-20th Century, as showmen introduced the public to such modern inventions as anesthesia, laughing gas, microscopes, adding machines, etc.-- making each of these inventions into a show to entertain, amaze and astonish.
The element of danger when it came to electric shows-- demonstrating electric chairs and electricity in general-- were less than most thought, as the showmen knew how to dazzle without killing anyone.