Since antiquity, the exemplum can be proven in numerous types of texts, as it fulfills a notable didactic and rhetorical function: On the one hand it serves to a deductive illustration of common doctrines; on the other it is until the Enlightenment the scientific basis of cognition: in the view of medieval artistotelists, of who FRANCIS BACON was (in a special sense) one of the last champions, the exemplum takes on an inductive function: the sensual perception of the exampla generates the understanding of the universal, as the exemplum always refers to the exemplar, to the original form. Regarding the eminent deductive/inductive significance of the exempla, it is not surprising that they are an essential factor in dietetic literature. Whereas such exemples were very rare in the general literature on health care written by physicians and in specific papers of old-age assistance, they formed an integral part of texts composed for a large public by medical laymen such as (Ps.-) ROGER BACON, MARSILIO FICINO, ALVISE CORNARO or FRANCIS BACON. In these studies, the issue of a natural limit of human life was discussed intensively. In this context the "historical" sources were of high importance, even if, from a todays point of view, their use was completely non-historical. Often their crude instrumentalization and new interpretations can only be understood in the scholarly context of the time: E.g. in debates of specialists with outsiders or when serving as argument for physiological theories and therapeutical regimes. Not until late Renaissance, the historical exemple was replaced by the individual experience. It is striking that most of all historical exemples found in dietetic papers were positive. This humanistic and Christian ideal concept of old age, which completely contradicts the medical reality, had obviously a stronger fascination on the authors of early modern times than the inductive function of negative exempla (which are very important for a rational reasoning). Besides the scientific exemple, it is the idealizing one which, in the dietetic texts, gradually assumes the moral function of not discouraging the often aged readers, but of encouraging them to a constructive way of living.