delivered the opinion of the court, November 15th 1875.
It is an unusual practice for the District Attorney to submit points to the court in a capital case. In my own experience I have never known it to be done, nor is it easy to see the object, as the Commonwealth is concluded by the verdict. In this case it has resulted disastrously. The only substantial errors assigned are to the answers of the court to the points submitted for the Commonwealth.
The first and second assignments of error are not sustained. They were not seriously pressed upon the argument, and I may pass them without further comment. But there was error in affirming the Commonwealth’s first point. In the case of an antecedent threat and a present provocation, it is for the jury to find whether the killing was in pursuance of the previous threat, or was the result of the immediate provocation. The effect of the affirmance of this point was to throw the burden of proof upon the prisoner. It required him to prove a negative ; that a previously formed purpose no longer existed. As there is no process by which the operation of the mind can be photographed, this was laying a heavy, if not impossible, burden upon the prisoner. Under our statute defining the degrees of murder, the presumption against the accused rises no higher than that the homicide is murder in the second degree: Commonwealth v. Drum, 8 P. F. Smith 9. Whenever it is sought to convict of murder in the first degree, the burden of proof is upon the Commonwealth to show the circumstances necessary to raise the offence above murder of the second degree. Nor can this burden be shifted from the Commonwealth upon the shoulders of the defendant. The learned judge was doubtless misled by the text in Wharton’s American Criminal Law, page 955, which is substantially in the language of the Commonwealth’s point. Many of the text-books, as well as authorities outside of the state, are not to be relied upon by reason of our peculiar division of homicide into murder of the first and second degree. In Commonwealth v. Drum, .before cited, the present chief justice, who tried the case, refers to these distinctions and the general law of homicide with great accuracy.
In the Commonwealth’s second point the same idea is repeated, though in a less objectionable form. It was not perhaps technical error to affirm it, yet unexplained it may not have been understood by the jury. Upon what evidence may the jury find that the prisoner had abandoned his previous purpose to take the life of the deceased? He cannot prove a negative. The purpose may have been formed years before and long since abandoned. It was therefore a question for the jury, upon all the evidence in the case, to determine whether the prisoner killed the deceased in pursuance of his previously formed design to take his life, or *317■whether it was the result of a provocation occurring at the time of the killing.
The law of homicide excusable on the ground of self-defence was not correctly stated in the Commonwealth’s sixth point, and it was therefore error to affirm it. It is not necessary that a man shall be in actual imminent peril of life, or of great bodily harm, before'he may slay his assailant. It is sufficient if in good faith he has a reasonable belief, founded upon the facts as they appear to him at the time, that he is in such imminent peril, even though it should afterwards appear that he was mistaken. The law will not hold a man to absolute correctness of judgment under such trying circumstances.
We do not regard this error as cured by the general charge. An obscure answer may be aided in this manner, but not one that is palpably erroneous. Beside, the general charge upon this branch of the case is not consistent with itself, and may have left the jury in doubt as to what the law really was.
The judgment of the Oyer and Terminer is reversed; a venire facias de novo awarded, and the record remitted to said court for another trial.