This paper examines medical writing in Karl Philipp Moritz’ Journal of Empirical Psychology by looking at the alterations Moritz made to his sources. It shows how he rearranged the data in order to introduce a new type of text into psychology: the case or case study. He did so by altering the main parts of a report that had been published a few years earlier. In rewriting the report, Moritz introduced not only a new type of text but also a (...) style of reasoning; i.e. the casuistic form of thinking that became more widely acknowledged only later in the course of experiential psychology. The paper thus links writing techniques in psychology to the rise of a type of text and a new style of reasoning. (shrink)