Upon the question of premeditation and deliberation, an essential element of the crime of first degree murder, the defendant may make the affirmative defense that, because of want of mental capacity, he was incapable of forming the deliberate purpose to kill; and may show that such mental incapacity was brought about by drunkenness. S. v. Edwards, 211 N. C., 555; S. v. Murphy, 157 N. C., 614; S. v. Shelton, 164 N. C., 513.

It is incumbent upon a defendant who relies upon such a defense to find support for it in his own evidence or that of the State; but it is not required that it be proven beyond a reasonable doubt. Since the instruction to the jury is not clear on that point, but is susceptible to the interpretation that the burden was upon the defendant to prove his matter of defense beyond a reasonable doubt, it must be held for error.

New trial.