(concurring). When, in Commonwealth v. A Juvenile, 365 Mass. 421 (1974), the court was approving *465the forensic use of polygraph results, thus departing from Commonwealth v. Fatalo, 346 Mass. 266 (1963), the dissenting Justices ventured to doubt that the question was best resolved by applying only the usual process of judicial lucubration. They suggested that a suitable team should be asked to undertake a study which, if favorable to the general idea of admitting evidence deriving from the polygraph technique, could propose court rules laying down definite limits and detailed procedures. There was another suggestion, that if the question was indeed to be answered solely through judicial decision, it would be peculiarly important to follow and in due course to describe and assess the consequences as they emerged in actual practice at the trial court level. I continue to regret that the opportunity for rule making was lost and no attempt at follow-up was inaugurated. Failing either kind of aid, caution is called for in the case by case elaboration of the subject, and in that light the main opinion herein has some considerable virtues. It describes certain features of the polygraph method which should discourage any routine acceptance of polygraph results, and on analysis it trims down the purposes for which those materials may be admitted in evidence. I concur, although with misgivings as to whether the analysis would not justify rather more stringent limitations.