[Bertha Röntgen or the transparency of the hand].

It is to Wilhelm Conrad Röntgen, the first elected "radiologist" of our Academy and the first Nobel Prize winner in physics, that we owe the transparency of the hand. We celebrate today the centenary of the great scientific discovery which was to revolutionize the diagnosis, and thereby the treatment, of a large number of illnesses the discovery of X-rays. It would be unjust not to link the name of this scientist with that of his wife, Bertha, who, ignorant of the dangers of all "novel medical inventions" volunteered her own hand for his research experiments: the hand which was to bring to the world tangible proof of this remarkable discovery. To a lesser degree, but nonetheless essential, we acknowledge, albeit not in exhaustive detail, all the progress made by the work of pioneers using this new investigative technique. So let us now return to the hand:--a body part which it was easy to immobilize, remembering that in those days a single radiographic exposure took up to an hour to obtain,--we will consider the immortalised hand of Bertha Röntgen,---to whom this address is dedicated,---and its radiographic exposures which allow us to appreciate the advances and to perceive the limitations of this technique. They also enable us better to envisage future investigative approaches whereby a deeper knowledge of the human body may be acquired. We note that compared with the histopathological sciences, imaging is not specific. Numerous microscopic structures, in particular neurological and vascular ones, are still insufficiently well visualised and the transmission pathways between the hand and the central nervous system deserve better characterisation. Current, research programmes are attempting to overcome these limitation of modern imaging. All the experience gained in studying the transparency of the hand, as we have discussed, is applicable to every part of the human anatomy. To credit: Röntgen's discovery with all its originality, we could say that the hand was to radiology what the brain was to CT and MRI scanning: an exceptional victory is rendering the human body transparent.