OPINION
ROBERTS, Justice.On January 16, 1975, following a trial by jury, appellant was found guilty of murder of the third degree and aggra*334vated assault. Post-verdict motions were filed and denied, and concurrent sentences of seven and one-half to fifteen years on the murder charge, and two and one-half to five years on the aggravated assault charge, were imposed. This appeal followed. We affirm.
I
We deal initially with appellant’s objections to the trial court’s pre-trial rulings. First, appellant argues that the trial court erred in denying his motion to strike the array of petit jurors. Appellant alleged that the jurors were selected only from voter lists, that such a method of selection tends to under-represent the poor, and that therefore the petit jury would not represent a fair cross-section of the community.
It is, of course, clear that the sixth amendment to the United States Constitution requires state petit juries to reflect a fair cross-section of the community. See Taylor v. Louisiana, 419 U.S. 522, 95 S.Ct. 692, 42 L.Ed.2d 690 (1975). And it may very well be that voter lists as a general matter significantly under-represent certain identifiable segments of the community, including poor people. See Kairys, Kadane & Lehoczky, Jury Representativeness: A Mandate for Multiple Source Lists, 65 Cal.L.Rev. 776, 805-809 (1977). But we have no idea whether this general proposition was true in York County at the time of trial. No proof was submitted to demonstrate the extent to which the poor were not present on the voter rolls. Appellant simply did not show that an unrepresentative array in fact resulted from using voter registration lists.
This case is therefore governed by our recent decision in Commonwealth v. Jones, 465 Pa. 473, 350 A.2d 862 (1976). There appellant challenged an array of jurors chosen solely from voter registration lists on the theory that such a method of selection resulted in systematic racial discrimination. We found, however, that appellant had not shown that “the list itself reflects discriminatory practices.” Id. 465 Pa. at 480, 350 A.2d at 866. Similarly, although the motivation *335of those who chose to use voter lists was not relevant to appellant’s claim of unrepresentativeness, appellant here was at least required to show the extent to which the voter list reflected exclusion of the poor. This he has not done and accordingly his claim must fail.
Appellant next asserts that it was error for the trial court to grant the Commonwealth’s motion to amend the indictment so that it would charge murder of the third degree, rather than murder of the second degree. The indictment charged appellant with “intentionally, knowingly, recklessly or negligently” causing the death of another human being, but the indictment indicated that such conduct violated sections 2502(a) and (b) of the Crimes Code (first and second degree murder), rather than 2502(a) and (c) (first and third degree). It is clear, however, that the words used encompass the charge of third degree murder. It was thus within the power of the trial court to allow the amendment, which corrected a “defect in form” and did not “charge an additional or different offense.” Pa.R.Crim.P. 220.
Nor did the trial court deny appellant the right to argue against the motion. The court asked appellant’s counsel, prior to granting the motion, whether he had any additional arguments not contained in his pleadings; he replied that he had nothing further.
II
Appellant raises three objections to the trial proceedings. First, appellant claims it was error to admit into evidence a knife sheath which the investigating police officer found in the immediate area of the stabbing. The officer testified that he found it within one hour of the stabbing and that he had been at the crime scene continuously for that period. A witness to the stabbing testified that he saw appellant holding something in his hand that looked like a “knife holster,” but the witness was unable to positively identify the sheath in question.
*336The admission of such evidence is largely within the discretion of the trial judge. See Commonwealth v. Ford, 451 Pa. 81, 85, 301 A.2d 856, 858 (1973) (citing cases). Testimony positively identifying the sheath as appellant’s is unnecessary. See Commonwealth v. Yount, 455 Pa. 303, 316, 314 A.2d 242, 249 (1974). So long as a proper foundation is laid to show the relevance of the evidence, it can be admitted; the question then becomes the weight that should be assigned to it by the fact finder. See Commonwealth v. Ford, supra, 451 Pa. at 84, 301 A.2d at 857 (citing cases). On that point counsel was free to argue, as he did, that the sheath found by the officer was not clearly shown to have been appellant’s and that it could have been placed there by other witnesses to the stabbing. We think the trial court could, properly conclude that the jury was capable of assessing the probative value of the sheath in light of all the surrounding facts.
Next, appellant asserts that it was error to admit into evidence certain photographs of the victim and the victim’s shirt. The question whether this type of evidence is admissible is one we have frequently encountered and the test to be applied is well established. It involves weighing the necessarily inflammatory nature of this evidence against its “essential evidentiary value.” See, e. g., Commonwealth v. Petrakovich, 459 Pa. 511, 521, 329 A.2d 844, 849 (1974); Commonwealth v. Ford, 451 Pa. 81, 87, 301 A.2d 856, 859 (1973); Commonwealth v. Powell, 428 Pa. 275, 278-79, 241 A.2d 119, 121 (1968). This test applies both to the pictures and the other demonstrative evidence. See Commonwealth v. Yount, 455 Pa. 303, 317, 314 A.2d 242, 250 (1974).
This weighing process, however, is often difficult and we cannot say that the trial court here abused its discretion in assessing the balance in favor of admissibility. The evidence was not highly inflammatory; the two pictures of the body, for example, were in black and white, the blood around the wound had been cleansed before the pictures were taken, and the pictures showed only the victim’s chest. As for its essential evidentiary value, an important factual issue in the *337case was whether the victim was stabbed twice in deliberate fashion, or was killed in a struggle for the knife. The photographs showed two wounds close together and no additional scratches such as might have occurred in a struggle. The shirt, however, showed only one hole. This discrepancy was noted initially by defense counsel in cross-examining the coroner; the prosecution later introduced the shirt itself to show where the hole was in relation to the wounds. Given this evidentiary value of the items, and the very slim “likelihood of inflaming the minds and passions of the jurors” that the evidence in question shows, see Commonwealth v. Powell, supra, 428 Pa. at 279, 241 A.2d at 121, we cannot say it was error to admit into evidence the shirt and photographs.
The third trial error advanced involves the charge to the jury. We do not reach the merits of this claim, however, because it has not been properly preserved for appeal. Our Rules of Criminal Procedure, and our case law, require that unless specific objection is made to an alleged error in the charge, the error cannot be raised on appeal. See Pa.R.Crim.P. 1119(b); Commonwealth v. Clair, 458 Pa. 418, 326 A.2d 272 (1974). In this case appellant proposed six points for charge. The court reviewed these points at the end of his charge, affirming them in part. Immediately thereafter the judge asked whether counsel had any exceptions or additions. Defense counsel replied that he had none.
This case is thus directly controlled by Commonwealth v. Hilton, 461 Pa. 93, 334 A.2d 648 (1975). There, as here, defense counsel submitted points for charge and was given the opportunity to make corrections after the court finished its charge. There, as here, defense counsel stated he had no objections, apparently finding the court’s instructions unobjectionable despite the refusal of the requested instructions. We accordingly held that the trial court’s refusal to give two of the requested points for charge could not be raised on appeal.
The reasons for requiring specific objection after the charge, even where points for charge had previously been proposed, are apparent. Primarily, it ensures that the court *338is given opportunity to avoid error. See Commonwealth v. Sisak, 436 Pa. 262, 269, 259 A.2d 428, 432 (1969). Here, as is so often the case, the court gave some of the requested instructions in modified form. Additional corrections might very well have avoided error.
Ill
Appellant raises one claim with respect to post-trial rulings. Appellant claims he is entitled to a new trial in light of evidence discovered after the close of testimony. The evidence consists of a civil complaint, filed the day trial began, in which a witness for the Commonwealth claimed that the owner of the bar where the stabbing occurred had been negligent in serving liquor to the deceased, and alleged that the deceased was a man of “known intemperate habits” who was visibly intoxicated at the time. Appellant contends that this complaint demonstrates that the witness committed perjury at trial and that this perjured testimony was employed with the knowledge of the Commonwealth.
Appellant’s claim is without merit. First, it does not appear that the complaint even contradicts the witness’ testimony. Contrary to appellant’s assertion, the witness never testified that the victim was sober on the night in question. Nor did the witness testify as to the victim’s drinking habits; he merely testified that the victim’s temperament was “about the same” whether he was drinking or not.
Second, appellant presents no more than a bare allegation that the Commonwealth knew about the civil complaint. Presentation of perjured testimony, or allowing perjury to go uncorrected at trial, is a serious matter, requiring reversal as a matter of constitutional law. See, e. g., United States v. Agurs, 427 U.S. 97, 103-04, 96 S.Ct. 2392, 2397, 49 L.Ed.2d 342 (1976); Commonwealth v. Alston, 430 Pa. 471, 243 A.2d 404 (1968). Appellant cannot succeed on such a claim without making any showing that, in fact, the Commonwealth acquiesced in, or knew; it was presenting perjured testimony.
*339Nor is this evidence such that it would entitle appellant to a new trial on the basis of our usual rule on after-discovered evidence. The evidence here simply does not satisfy the test for when such evidence requires a new trial. It is, at best, cumulative, given other witness’ testimony about the victim’s drinking, both on the night in question and before, and it certainly would not likely compel a different result. See, e. g., Commonwealth v. Tervalon, 463 Pa. 581, 586-87, 345 A.2d 671, 674 (1976) (citing cases); Commonwealth v. Schuck, 401 Pa. 222, 229, 164 A.2d 13, 17 (1960) (citing cases), cert. denied, 368 U.S. 884, 82 S.Ct. 138, 7 L.Ed.2d 188 (1961).
Judgments of sentence affirmed.
EAGEN, C. J., concurs in the result. POMEROY, J., filed a concurring opinion. MANDERINO, J., filed a dissenting opinion in which NIX, J., joins.