“Let me begin by instructing you on the law of homicide. The statute on homicide is divided into two divisions, which are again subdivided. The two chief divisions are homicide that is criminal and homicide that is not.
“Criminal homicides are classed as murder in the first degree, murder in the second degree and manslaughter in the first and second degree. Homicide unless it is excusable or justifiable is murder in the first degree, when committed with deliberate design to effect the death of the person killed.
“If committed with design to effect death without premeditation or deliberation, it would not constitute murder in the first degree but would constitute murder in the second degree. If committed without design to effect death in the heat of passion with a deadly weapon that would constitute manslaughter in the first degree.
“All lesser criminal homicides are embraced within the definition of manslaughter in the second degree.
“Homicides not criminal are classed as justifiable and excusable homicide. Homicide is justifiable when committed in the lawful defense of the slayer or his wife or child or master or servant or anybody connected with him in close relation.
“The defense here is that the defendant was insane at the time he committed the act and the law applicable in the defense of insanity is found in sections 20 and 21 of the Penal Code. Section 20 provides that an act done by a person who is an idiot, imbecile or lunatic is not a crime.
“But section 21 limits section 20 as follows:
“‘A person is not excusable from criminal liability as an idiot, imbecile, lunatic or insane person except upon proof that at the time of committing the alleged crime he was laboring under such a defect of reason as either not to know the nature or quality of the act or to know that the act was wrong.’
“Before murder in the first degree can be done, a distinguished jurist has said, it must appear that there was some act of deliberation and premeditation. This, of necessity, is for the comprehension of the jury.
“If you are satisfied that there was a design to effect death, but without deliberation and premeditation, you may find murder in the second degree. The defendant may be convicted under this indictment of murder in the first or second degree or manslaughter in the first degree.