Speaking about aesthetics of biology means to refer immediately to the German cultural area; this volume instead studies a chapter rather less well known: the interweaving of aesthetic theories and biological theories in French area, from the Medical School of Montpellier until Bergson, through Comte, Claude Bernard, Ravaisson and Guyau. A red thread connects authors although characterized by different approaches: the use of the sphere of art in order to draw examples or models useful to think about life in its originality, in the aspects that make it irreducible to a simple mechanism. The aesthetic notions of beauty, taste, genius, creation etc. act at two levels: within the framework of the new biological science, they illustrate physiological processes that can not be represented in other ways; in the framework of philosophical research, they indicate strategies to develop a wider and ductile pattern of rationality, whose basic paradigm is no longer the repetitiveness of a machine but the creativity of life. At the same time, the aesthetic thinking is influenced by the scientific-philosophical reflection on man, obtaining valuable solicitudes to reformulate methods and categories.