They turned medicine inside out

This year marks the centenary of the discovery of x rays by Wilhelm Rontgen. On 8 November 1895 Rontgen observed what led to a revolutionary diagnostic procedure in medicine: each time he passed a high electric voltage through a covered vacuum tube in a darkened room a barium platinocyanide screen lying nearby emitted a mysterious light or fluorescence. Rontgen realised that the invisible rays that were producing the fluorescence had not previously been described, and he called them x rays.1 2 3

Rontgen did not report his discovery immediately but spent the following seven weeks in his laboratory, meticulously performing experiments and recording his observations. An x ray picture of his wife's hand convinced him of the potential role of the new ray, and in December he presented a …