The defendant appeals (G. L. c. 278, §§ 33 A-33G) from his conviction on an indictment charging him with the unlawful distribution of a Class A controlled substance (heroin). The jury heard testimony that Detectives Vincent Logan and Willis Saunders, Jr., while conducting a surveillance operation in the South End of Boston, observed through binoculars a man, whom they knew well and recognized as the defendant, handing a tinfoil packet to another individual in exchange for money. The transaction occurred at approximately 8:00 p.m. The recipient of the packet was pursued and arrested by Logan and Saunders a few blocks from where he had been observed by the officers. The packet was seized and its contents were later analyzed and found to contain heroin. After this arrest, a radio call naming the defendant went out to other members of the surveillance team. One of the officers so alerted saw the defendant and chased him on foot until'he escaped down a nearby alley. Two days later the defendant was arrested by Detective Logan pursuant to a warrant.
The defendant did not testify at trial, but his wife and five relatives testified that on the night in question the defendant had been with them at the celebration of a family birthday. Four of the witnesses stated that the defendant had been in their company for several hours starting at approximately 7:30 p.m. On cross-examination the assistant district attorney asked five of the six witnesses whether they had testified at the probable cause hearing in the District Court, and each witness responded in the negative.1 In his closing argument the prosecutor commented on the failure of the alibi witnesses to testify in the District Court.
1. The defendant contends that the prosecutor’s questioning of the alibi witnesses to elicit that none of them *803had testified in the District Court violated G. L. c. 278, § 23,2 and denied him a fair trial. Given the particular circumstances of this case, it is unnecessary for us to discuss whether that questioning was within the range prohibited by § 23. See Commonwealth v. Maguire, 375 Mass. 768, 774-775 (1978); Commonwealth v. Morrison, 1 Mass. App. Ct. 632, 637 (1973). The record reveals that at the trial in the Superior Court, prior to any testimony or cross-examination of the alibi witnesses, the attorney who had represented the defendant at the probable cause hearing testified. He responded in the negative to a question put to him by defense counsel as to whether anyone other than Detectives Logan and Saunders had testified at the probable cause hearing. We conclude that where defense counsel elicited testimony from the defendant’s own witness indicating that the alibi witnesses had not previously testified, questioning of the alibi witnesses by the prosecutor that brought out the same information did not harm the defendant. See Commonwealth v. Paradiso, 368 Mass. 205, 210-213 (1975).
2. The short answer with regard to the alleged impropriety of the prosecutor’s comments during closing argument is that there is nothing before us to review where no exception was taken at trial. Commonwealth v. Therrien, 371 Mass. 203, 207 (1976). Commonwealth v. Cooper, 4 Mass. App. Ct. 782 (1976), and cases cited.
3. The defendant’s final contention is that the trial judge’s charge to the jury on alibi evidence erroneously singled out the alibi for special scrutiny and shifted the burden of proof to the defendant. The alibi portion of the charge drew some of its language from Commonwealth v. *804Webster, 5 Cush. 295, 319 (1850), which has been disapproved by the Supreme Judicial Court and this court in past decisions (Commonwealth v. McLeod, 367 Mass. 500, 501-502[1975]; Commonwealth v. Cobb, 5 Mass. App. Ct. 421, 423 [1977]), but the charge did not contain the offensive burden-shifting language of Webster.3
Although the defendant argues vigorously on appeal that the charge was patently prejudicial, there was no exception taken to the charge at trial. Nor did defense counsel request an instruction that an alibi may be the "only refuge of the innocent.” See Commonwealth v. McLeod, supra at 502. Contrast Commonwealth v. Cobb, supra at 423. Recognizing that in certain "rare and unusual circumstances” (Commonwealth v. Foley, 358 Mass. 233, 236 [1970]) a verdict may be set aside in order to prevent "a substantial risk of a miscarriage of justice” (Commonwealth v. Freeman, 352 Mass. 556, 564 [1977]) even if there had been no objection at trial (Commonwealth v. Mello, 5 Mass. App. Ct. 825 [1977]; Commonwealth v. Borges, 2 Mass. App. Ct. 869, 870 [1974]), we have read the charge with care. The quotation from the Webster case in isolation would indeed have required reversal if proper exceptions had been taken, because of its reference to an alibi as a "defense often attempted by contrivance and subornation of perjury” and its failure to point out that "an alibi may be the only refuge of the innocent.” Commonwealth v. Cobb, supra at 424. Here, however, there was sufficient emphasis placed upon the Commonwealth’s burden of proof to mitigate the effect of the Webster language quoted in the charge. The judge expressed the duty of the Commonwealth to prove its case beyond a reasonable doubt at least seven times throughout the charge, and one of those references was made at the conclusion of the alibi instruction. Compare Sullivan *805v. Scafati, 428 F.2d 1023,1024 (1st Cir. 1970), cert. denied 400 U.S. 1001 (1971). Though the question is close, in view of the structure and content of the charge and the overwhelming evidence of guilt, we do not conclude that there was a likelihood of a substantial risk of a miscarriage of justice.
Judgment affirmed.
Defense counsel saved an exception to this line of inquiry after the second and third witnesses were examined, but neither objected nor excepted to similar questioning of the other witnesses.
General Laws c. 278, § 23, provides: "At the trial of a criminal case in the superior court, upon indictment or appeal, the fact that the defendant did not testify at the preliminary hearing or trial in the lower court, or that at such hearing or trial he waived examination or did not offer any evidence in his own defence, shall not be used as evidence against him, nor be referred to or commented upon by the prosecuting officer.”
"If, therefore, the proof of the alibi does not outweigh the proof that he was at the place when the offence was committed, it is not sufficient.” Commonwealth v. Webster, 5 Cush. 295, 324 (1850).