Persons who act from impulse liable to be influenced—Principle of imitation, a natural instinct—Cases related by Cabanis and Tissot—The suicidal barbers—Epidemic suicide at the Hôtel des Invalides—Sydenham’s epidemic—The ladies of Miletus—Dr. Parrish’s case—Are insanity and suicide contagious? The most singular feature connected with the subject of suicide is, that the disposition to sacrifice life has, at different periods, been known to prevail epidemically, from a perversion, as it has been supposed, of the natural instinct of imitation. This is not only the case with reference to suicide, but is witnessed also in cases of murder. The atrocities of the French Revolution are, to a certain extent, to be traced to the influence of this imitative principle. Persons whose feelings are not thoroughly under their command, who act from impulse and not from reflection, are very prone to be operated upon by the cause referred to. Man has been defined an imitative animal; and in many instances we witness this propensity controlling almost irresistibly the actions of the individual. Tissot relates the case of a young woman in whom this faculty was so strongly developed that she could not avoid doing everything she saw others do. Cabanis gives the account of a man in whom the tendency to imitate was so strongly marked, and active, from disease, that “he experienced insupportable suffering” when he was prevented from yielding to its impulses. A woman, in the ward of an hospital, will be seized with an epileptic fit; in the course of a short period, other cases will occur in the same ward. A child was brought into one of our metropolitan hospitals, labouring under a violent attack of convulsions. She had not been in the house five minutes before three children who were present were seized with spasmodic convulsions of a similar character. The commission of a great and extraordinary crime produces not unfrequently the mania of imitation in the district in which it happened. A criminal was executed at Paris, not many years ago, for murder. A few weeks afterwards, another murder was perpetrated; and when the young man was asked to assign a reason for taking away the life of a fellow-creature, he replied, that he was not instigated by any feeling of malice, but, after having witnessed the execution, he felt a desire, over which he had no control, to commit a similar crime, and had no rest until he had gratified his feelings. It is only on the same principle that we can account for the following singular case of suicide. It is related by Sir Charles Bell, in his “Institutes of Surgery.” The surgeon of the Middlesex Hospital who preceded Sir Charles Bell went into a barber’s shop, in the neighbourhood of the institution, to be shaved. As the barber was operating upon his chin, the conversation turned upon the case of a man who had been admitted the previous day into the hospital, and who had attempted, unsuccessfully, to kill himself, by cutting his