"Eder was the director of an institute for graphic processes and the author of an early history of photography. With the photochemist Valenta, he produced a portfolio in January 1896, less than a month after Wilhelm Conrad Röntgen published his discovery of X-rays. Eder and Valenta’s volume... demonstrated the X-ray’s magical ability to reveal the hidden structure of living things. Human hands and feet, fish, frogs, a snake, a chameleon, a lizard, a rat, and a newborn rabbit are all presented in exquisitely printed photo-gravures, as are carved cameos and an assortment of natural materials. In an era when photography’s ability to accurately depict the visible world had become commonplace, this newfound capacity to record the invisible opened up a host of possibilities, both scientific and aesthetic" (https://www.metmuseum.org/art/collection/search/296322, accessed 05-2018).