The insane man may have wrong ideas without logical reason for them. Thus, an insane man may declare that a beautiful actress is in love with him, when there is absolutely no foundation for such an idea. Or, he may believe that he can lift 500 pounds and run faster than a locomotive can go, while in reality he is so feeble as scarcely to be able to walk, and unable to dress himself. Such ideas are delusions. Sane people may be mistaken; they may have hallucinations, illusions and delusions; but they abandon their mistaken notions and correct their judgment at once, on being shown their errors. Sane people see the force of logical argument, and act upon it, abandoning all irrational ideas. The insane person, on the other hand, cannot see the force of logical argument; cannot realize the absurdity or impossibility of error. He clings to his own beliefs, for the evidence of his perverted senses or the deductions from his disease-irritation are very real to him. When we find this to be the fact we know he is insane. Yet we must not confound delirium of fever with insanity. A patient suffering from typhoid fever may have a delusion that there is a pail by his bed into which he persists in throwing articles. Or he may have the hallucination that he is being called into the next room, and try to obey the supposed voice. Certain delusions are commonly found in certain types of insanity. Depressed patients frequently manifest the delusion that they have committed a great sin, and are unfit to associate with anyone. Excited and maniacal patients often believe they are important personages--kings or queens, old historical celebrities, etc. Paranoiacs commonly have delusions of persecution and of a conspiracy among their relatives or their associates or rivals. Victims of alcoholic insanity have delusions regarding sexual matters, and generally charge with infidelity those to whom they are married. General paretics in most cases have delusions of grandeur; that is, false ideas of great strength, wealth, political power, beauty, etc. The emotion which accompanies mental activity is generally exaggerated in all insane people except the demented. One sees extreme depression, or undue elation and exaltation, or silly glee and absurd joy. Intensity of emotion is frequent. _Crimes Impulsively Committed by the Insane_