This paper aims to show that the semiology of crime in Balzac opens out onto a physiology of energy. The hyperbolic strength that characterises his criminals informs their bodies and manifests itself in a multiplicity of signs, which constitute the foundation of a configuration of the bloody act that superimposes image and violence, plasticity and potentiality, stroke and blow. What is interesting is that this gallery of images of galvanised brutality arises at the intersection between contemporary medical language and the author’s personal imaginary world : the portrait of the criminal, intertwining the theory of temperament with a complex metaphoric network of eruptions and explosions, insists on the compactness of a body devastated by tensed muscles and bulging nerves in which a physics of violence can inscribe itself.