Dr. Pierce, who had treated the plaintiff’s intestate after the accident, was not living at the time of the trial. Subject to the defendant’s exception, the plaintiff was permitted to answer the question, “While Dr. Pierce was treating Mr. Little, did Dr. Pierce tell you what was the cause of his condition?” The purpose was to disclose the opinion expressed by the physician either as to the nature of the ailment from which his patient was suffering or as to the cause which was responsible for that condition.
It may be assumed, as urged by the plaintiff now and at the trial, that if Dr. Pierce were living he would be permitted as attending physician to give certain opinion evidence in connection with the facts coming under his observation, without qualifying as an expert. See Hastings v. Rider, 99 Mass. 622. But it does *504not necessarily follow that the statement of an opinion expressed by him would be admissible under the statute.
Declarations of deceased persons, in order to be admissible under R. L. c. 175, § 66, must have been made, not only in good faith, but “upon the personal knowledge of the declarant.” In general they must be derived from the exercise of the declarant’s own senses as distinguished from opinions based upon data observed by him or furnished by others. While it often is difficult to trace the logical or legal distinction between facts and opinions (see Wigmore on Evidence, § 1919), this court, in construing the statute, has recognized that where the declaration admittedly is one of opinion it is not admissible. Slotofski v. Boston Elevated Railway, 215 Mass. 318, 321. Whitcomb v. Whitcomb, 217 Mass. 558. Johnson v. Foster, 221 Mass. 248, 251. Gray v. Kelley, 190 Mass. 184. In the present case the facts on which the trial judge admitted the question are undisputed, and the admissibility of the declaration is before us for review on the defendant’s exception. Ames v. New York, New Haven, & Hartford Railroad, 221 Mass. 304. It seems plain that the question called for a statement of Dr. Pierce’s opinion and not for any information within his “personal knowledge,” even if it was asked in order to bring out the physician’s diagnosis. If it was designed to evoke the answer actually given by the witness, it was open to the further objection that the opinion it called for was not even a medical one, on which the physician presumably could testify if he were living. After the judge had ruled that the question was admissible, it was put to the plaintiff in the form, “What did Dr. Pierce say was the cause of his condition?” and the answer given was, that the cause of the condition of his patient was “the accident, being thrown out of the carriage.” It is not contended that Dr. Pierce witnessed the accident, or had any personal knowledge that Mr. Little was thrown from his carriage.
We are unable to say that the error in admitting the declaration did not injuriously affect the substantial rights of the defendant. The main issue under the second count was whether the accident was the cause of the death of the plaintiff’s intestate. There was evidence that for a long time before this occurred he had been suffering from hardening of the arteries, which might have resulted in his death even if the accident had not happened. The state*505ment of the attending physician, to the effect that the cause of Mr. Little’s dying condition was not the hardening of his arteries but the fall from his carriage, may have had a controlling influence on the verdict of the jury.
It follows that the entry must be
Exceptions sustained.