In the Archives de Neurologie for December, 1904, Dr. Raoul Leroy, assistant physician at the Evreux Asylum, refers to the medico-legally important subject of pyromania in young persons of both sexes, a form of mental disorder which leads to acts of incendiarism. “Whenever reported fires occur,” he says, “in a village or in the country suspicion generally falls on persons of incomplete mental or physical development - weak-minded youths or girls - among the inhabitants and it generally proves to be well-founded.” The mental state of such incendiaries, says Dr. Leroy, is peculiar and characteristic. They are weak-minded and are often members of families in which epilepsy, insanity, or alcoholism occurs. Reference is made to the fact that among the peasant population of Normandy, where alcoholism prevails to a high degree, juvenile crimes of the nature of incendiarism are common. These feeble-minded delinquents are prone to set fire to buildings or other objects in revenge against their owners or in some cases merely to amuse themselves with the spectacle. A few cases, says Dr. Leroy, suffer from the influence of an obsession which irresistibly impels them to such acts, such cases forming a special form of insanity to which the term “pyromania” is applied. True cases of pyromania manifest themselves for the first time at the period of puberty. The following typical case is given in illustration of this affection. The patient or culprit in this case was a girl, aged 15 years, a domestic servant, who on three separate occasions had set fire to the house of her master. She was the child of respectable parents and at first no suspicion was entertained of her but on being questioned before the police at the third outbreak of fire she showed much agitation and finally confessed her guilt. “When she had stated the facts fully and was asked if she realised the wickedness of her crime,” she replied, “Something supernatural urged me to set the place on fire.” Although she was reasoned with and her wrong-doing demonstrated in the clearest manner “she remained unshakable and invariably repeated the same words in justification.” She had no reason to hate her master, there was no motive whatever of vengeance that impelled her, only a presumably morbid impulse. The medico-legal inquiry revealed the fact that a highly neurotic hereditary taint existed in the family; the grandfather was a man of excessively violent disposition, a first cousin was liable to periodic attacks of insanity during which he wandered about, the grandmother committed suicide at the age of 63 years, and the patient's mother was a very nervous, emotional, weak-willed woman afflicted with coxalgia. The patient herself was a child of but little intelligence and never could read and write correctly. Her character was excitable, violent, and impulsive, with a total lack of good judgment. At the age of 13 years she developed nocturnal somnambulism, walking all over the house in her sleep and having no recollection of it in the morning. The menstrual periods, which set in at the age of 15 years, were attended with headache, insomnia, and great nervous prostration. On one such occasion she had a hallucination that her bed was surrounded by flames and this was the starting point of her obsessions. Almost daily after this she felt the sudden morbid impulse to set something on fire. It grew stronger though she struggled against it, suffering great mental and physical distress in the process. The morbid obsession occupied her mind to the exclusion of all other ideas and caused such distress and agony that she could resist no longer. Taking a lighted taper she set fire to a packet of waste paper. This was followed by instant relief of distress and an agreeable feeling of satisfaction. These obsessions occurred from time to time and on three such occasions she set fire to outbuildings and parts of her master's house. The medical evidence taken before the magistrate in the trial of this patient showing the occurrence of insane impulses the patient was removed to the asylum. Dr. Leroy concludes that the morbid heredity on both paternal and maternal sides resulted in a brain liable to disorder and readily provoked to morbid impulse (in this case pyromania) on the occurrence of the stresses of puberty, a critical time in mental development.