This paper is devoted to an analysis of the relationship between case studies and the long term in the history of the life sciences, demonstrating the value of a polychronic approach to the study of the construction of a scientific object. A critical analysis of Paula Findlen’s classic case study of Francesco Redi demonstrated the radical difference between this approach and the naive view that the long term is the very form of science. The goal was to provide answers to several questions: Are there limitations specific to a case study? Shouldn’t the long term be reduced to the case study, to processes of a different nature, such as the construction of scientific objects and practices? Can an isolated case study address a long-term problem? To provide a basis for these answers, we propose an approach that distinguishes between the local context of origin, the historical field, and the historiographical field in relation to the construction of a scientific object and practices. By making a precise distinction between each field and its contribution to the construction of a scientific object, this approach also proposes a polychronic methodology to address the problem of anachronism.