The relationship between medicine and the study of life is as old as medicine itself. Nevertheless, historians have highlighted the great transformation that took place in the nineteenth century when first physiology and then bacteriology became important resources for the classification, diagnosis, and treatment of human diseases. In that period, significant links developed between the sites specializing in biological experimentation (i.e. laboratories) on the one hand, and the places of healing (i.e. hospitals, dispensaries) and public health offices on the other. Together, they helped to fashion modern, professional medicine. However, many historical studies have also argued that this mobilization of biological knowledge exerted a limited impact on medical practice in general, and clinical practice in particular.