(f) Z strikes B. B is by this provocation excited to violent rage. A, a bystander, intending to take advantage of B' s rage, and to cause him to kill Z, puts a knife into B' s hand for that purpose. B kills Z with the knife. Here B may have committed only culpable homicide, but A is guilty of murder. Exception 2.- Culpable homicide is not murder if the offender in the exercise in good faith of the right of private defence or person or property, exceeds the power given to him by law and causes the death of the person against whom he is exercising such right of defence without premeditation, and without any intention of doing more harm than is necessary for the purpose of such defence. Illustration Z attempts to horsewhip A, not in such a manner as to cause grievous hurt to A. A draws out a pistol. Z persists in the assault. A believing in good faith that he can by no other means prevent himself from being horsewhipped, shoots Z dead. A has not committed murder, but only culpable homicide. Exception 3.- Culpable homicide is not murder if the offender, being a public servant or aiding a public servant acting for the advancement of public justice, exceeds the powers given to him by law, and causes death by doing an act which he, in good faith, believes to be lawful and necessary for the due discharge of his duty as such public servant and without ill- will towards the person whose death is caused. Exception 4.- Culpable homicide is not murder if it is committed without premeditation in a sudden fight in the heat of passion upon a sudden quarrel and without the offender' s having taken undue advantage or acted in a cruel or unusual manner. Explanation.- It is immaterial in such cases which party offers the provocation or commits the first assault. Exception 5.- Culpable homicide is not murder when the person whose death is caused, being above the age of eighteen years, suffers death or takes the risk of death with his own consent. Illustration A, by instigation, voluntarily causes Z, a person under eighteen years of age, to commit suicide. Here, on account of Z' s youth, he was incapable of giving consent to his own death; A has therefore abetted murder.