X-rays

                     X-rays: A type of electromagnetic radiation used in medicine to pass through soft tissue and provide an image of a hard structure within such as part of the skeleton.

                    Wilhelm Rontgen (1845-1923) was professor of physics at the university of Wurzburg, Germany when in 18895, he was passing electron beams known at the time as cathode rays through a gas container at very low pressure. He discovered that under the right conditions - involving a darkroom, a darkend discharge tube, a fluorescent screen and a paper plate treated with barium platinocyanide - some materials appeared more clearly on the image than lighter ones in one image the hand of Rontgen's wife revealed her bones and a ring in black with a light grey shadow for the surrounding flesh. Rongton named the new phenomenon the X-ray, meaning "unknown ray". It was many years before scientists learned how the process worked and neither were the dangers of high- dosage X-rays at first understood.

                     Substance such as metals and calcium in bones absorb radiation more readly than soft tissue and so the X-ray quickly became a useful tool for medical examinations. Using X-ray technology, doctors could look for a broken bone or swallowed hard object and check for cancerous lumps or even lesions caused by tuberculosis. X-rays revolutionised the way in which doctors considered the diagonosis process itself and opened up many new avenues of scientific exploration.

                      Rontgen's discovery laid the foundation for sch diagnostic technology as ultra sound and electromagnetic scanners which look inside the body rather than making deductions from what can be seen on the outside. Through out the twentieth century, medical practionioners came to rely more and more on technological aids to back up or even inform their diagnosis rather than using experience and observation of symptoms to arrive at them.