In 1895, Röntgen discovers a new sort of radiation by chance. He calls it X-radiation. X-rays soon become common in medicine, as they are today. X-radiation, when it passes through the body, blackens the X-ray plate. Soft tissue like fat, muscle, and skin only absorb a trace of the radiation. In contrast, hard tissue like bone absorbs much of the radiation and thus leaves a white shadow on the X-ray photograph.