The paper reconstructs an emblematic case of the relationship between scientific models and metaphors, showing how it is just a metaphor to shape the new image of the life promoted by Claude Bernard in the context of nineteenth-century biology. In fact, the scientist chooses to map a field that is still little known by transferring properties and relations taken from the domain of the art. Using this heuristic fiction, Bernard can claim the originality of biological science and its independence from (...) the physical and chemical sciences, without putting into question its deterministic system and its status as an experimental science. (shrink)