Spots 
Sexual instinct serves as the foundation for social cohesion, morality, and artistic achievement rather than mere procreation. Normal sexual feeling balances physical drive with sentimental devotion, transforming raw biological imperative into refined affection. Disruptions in this balance alter both character and social conduct.
Nervous system degradation manifests as hyperesthesia, anesthesia, or paresthesia of the sexual instinct. Hereditary neuropathic taint often underlies functional disturbances, weakening brain centers responsible for moral restraint. Cerebral exhaustion and spinal irritation frequently trigger abnormal fluctuations in sexual impulse.
Anomalies of the sexual instinct express as sadism, masochism, fetishism, and contrary sexual feeling. Inversion represents a congenital neurological anomaly rather than an acquired vice or moral failing. Specific objects, suffering, or same-sex attraction replace normal heterosexual goals due to altered cerebral associations.
Medical jurisprudence requires evaluating whether a criminal act stems from pathological compulsion or conscious intent. Defendants acting under hereditary brain degeneration or sexual mania lack full legal responsibility for violent or public offenses. Courts must substitute psychiatric asylum treatment for punitive incarceration when morbid impulses drive the crime.
A foundational nineteenth-century forensic study examining sexual instincts, perversions, and legal responsibility.