Opinion by
Mr. Justice Fell,The plaintiff’s husband was a brakeman on the defendant’s road and was killed in an accident caused by the falling of a bridge on which his train was passing. The bridge was about eighty feet in length, and the iron superstructure rested on abutments at its ends and a pier at the middle of the creek it spanned. The creek was ordinarily quite small, but at the time of the accident the water was unusually high, while the water in the Allegheny river near by, into which it flowed, was 'low. This condition caused a very rapid current in the creek, and a strong pressure on one side of the bridge. The whole structure, including the abutments and pier, was carried away, *321and a freight car loaded with cement was carried seventy-five yards down the stream. The bridge had been used by the defendant for forty years, and there was no evidence of defective construction, or that the bridge had become unsafe.
The contention that the burden of disproving negligence was on the defendant cannot be sustained. The maxim res ipsa loquitur is an exception to the general rule that negligence is not to be inferred, but must be affirmatively proved except in cases of absolute duty or an obligation practically amounting to that of an insurer: Stearns v. Ontario Spinning Co., 184 Pa. 519; East End Oil Co. v. Penna. Torpedo Co., 190 Pa. 350. There was nothing in the circumstances that amounted to evidence from which negligence could be inferred and that relieved the plaintiff from the burden of proof. An offer was made to prove by a witness that he had made an 'investigation to ascertain whether the bridge had a substantial foundation and had found that there was “no permanent foundation upon the location that had been lately occupied by the pier.” The accident occurred in March. This witness had testified that because of the high water no examination could be made for several weeks after the accident, and the examination he made was in August, five months later, and that in the meantime there had been a change in the physical conditions by the action of the water, by the rebuilding of the bridge, and the dumping of stones in the bed of the stream. This offer was excluded. It was renewed with the addition that there had been no change in the conditions, as far as the foundations were concerned, between March and August. The second offer was excluded for the reason that the testimony would be inadequate to establish a defect in original construction. The ruling of the court on the offer as first made was clearly right, and we cannot say that the exclusion of the offer as finally made calls for a reversal. The witness had testified to facts which showed that the result of his examination in August could not be relied on as proof of the condition existing before the fall of the bridge and, if his testimony had come up to the offer, it would not have advanced the plaintiff’s case. It would still have been barren of proof that th'e foundations which had *322withstood the floods of forty years were defective, and that the fall of the bridge resulted from their giving away.
The judgment is affirmed.