The attempts of the German pathologist Emil Ponfick, who in 1901 attempted to reduce the gap between drawing and original object, show how objectives and implementation should be brought together in order to make the images appear self-evident: Ponfick tried to produce a topographical atlas of medical-surgical diagnostics. The image is taken from this atlas and shows a “Median Vertical Section Through The Abdominal And Pelvic Viscera of A Boy, Aged 17 Years, Who Died of Colloid Carcinoma of The Peritoneum And The Flexura lliaca”. In this atlas he wanted to give an overview of pathological changes not only of one organ but of an entire body region on panels “at a glance”. Ponfick strived for clarity and images “true to nature” (Ponfick 1901: 1ff.). To achieve this goal, he froze the bodies of deceased patients, cut them into frontal and horizontal sections and covered the cut surface with a frosted glass pane. The contours of the preparation were traced through the pane, transferred to tracing paper and coloured with watercolours on drawing paper. He worked together with an artist, but pointed out that he supervised the artistic work and simultaneously made an image of the preparation on a blackboard. So Ponfick assumed that a specific medical knowledge was needed to correctly structure the drawing process. In other words, concepts of the connection between pathology and diagnosis should be depicted in the images conforming to theory. In this way, he clearly expresses a dependence of the images on theory, although he considered the same images to be true to nature and thus diagnostically self-evident. Yet, the ultimate proof of the self-evidence of the images was in his eyes that he had contributed to their production and that the images were consequently authentic.