What is the test for a defendant who is convicted of murder of the second degree of the crime?

'In dividing the crime of murder into two degrees the legislature recognized the fact that some murders, comprehended within the same general definition, are of a less cruel and aggravated character than others, and deserving of less punishment. It did not attempt to define the crime of murder anew, but only to draw certain lines of distinction by reference to which the jury might determine, in a particular case, whether the crime deserved the extreme penalty of the law or a less severe punishment. * * * The fact that a severer penalty is to be imposed in one case than the other does not change the effect of a previous conviction, and the defendant who, on his own motion, secures a new trial, subjects himself to a retrial on the charge of murder, whether the first verdict was guilty of murder of the first or of the second degree. At the second trial he may, if the evidence justify such verdict, be found guilty of murder of the first degree.' See, also, In re Moore, 29 Cal.App.2d 56, 84 P.2d 57, and People v. McNeer, 14 Cal.App.2d 22, 57 P.2d 1018.