Braley, J.

The judge before whom these cases were tried without a jury having made certain findings of fact on which he ruled as matter of law, that the plaintiffs could not recover, they seek to have the findings set aside with the exception of those numbered two, three and four, and the rulings reversed.

It may be, as the plaintiffs contend, that by refined yet clear discriminations a substantial cause of action which they believed had been established by the evidence as stated in the first four findings was overthrown. But the adverse conclusion, that upon all the evidence the jolt which caused the forward part of the car during the transit to rise up on one side, lifting Mrs. Webber from her seat, and causing her to fall back with “ a hard thump,” was not attributable to a defective condition of the car, or of the roadbed and track, or to any negligence in operating the car, not having been unwarranted, cannot be set aside. It is familiar law, that the weight of testimony and the credibility of witnesses are not reviewable on exceptions.

The plaintiffs presented twelve requests for rulings which were refused. It is manifest that the first two were properly denied, and while the twelfth relating to the measure of damages became immaterial under the eighth finding that no liability of the defendant had been proved, the remaining requests, except the eleventh, directed the attention of the judge to the rule, that the plaintiffs’ evidence, which the findings show the judge believed, was sufficient proof of its liability. If the defendant had offered no evidence the requests would have been applicable, but evidently upon the testimony of its motorman and conductor, as stated in the fifth finding, the judge reached the conclusion as to the cause of the accident, which is set forth in the seventh finding. The determination of facts is, however, interwoven in the seventh and eighth findings with the important ruling found in the sixth to which the plaintiffs excepted. The ruling if it rested only on the first four findings might be subject to the plaintiffs’ criticism, that it went beyond the evidence. A jolt even if the car is not derailed, but which was sufficient to cause a passenger to pass through Mrs. Webber’s experience is not an *442ordinary incident of travel. Work v. Boston Elevated Railway, 207 Mass. 447. Nolan v. Newton Street Railway, 206 Mass. 384, 388. And its unexplained occurrence is presumptive proof of the carrier’s negligence. Egan v. Old Colony Street Railway, 195 Mass. 159, 161. But where as in the case at bar the defendant introduces evidence not perhaps to account for the accident, but to show that it had not been negligent, the plaintiffs still had the burden of proof, which the judge finally decided had not been sustained. Carroll v. Boston Elevated Railway, 200 Mass. 527, 534-536, and cases cited.

The ruling made in the ninth paragraph, that “ as matter of law . . . where a passenger, in an action against the carrier, relies upon a personal injury as the result of a jolt, it is not enough to prove a jolt from which injury resulted in fact, even though the jolt can be described as unusual or extraordinary, but it is necessary to prove that the jolt was such that it would have caused, or was sufficient to cause, actionable injury to a passenger in normal health in the same situation ” was incorrect, and the plaintiffs’ eleventh request in substance should have been given. The defendant was bound to exercise due care in the transportation of those who had been accepted as passengers, and if she was found to have been suffering from physical conditions making her more susceptible to the particular form of injury, shown by the evidence, this fact did not deprive her of all damages caused by the fall. Coleman v. New York & New Haven Railroad, 106 Mass. 160. Derry v. Flitner, 118 Mass. 131. Turner v. Boston & Maine Railroad, 158 Mass. 261, 266. Spade v. Lynn & Boston Railroad, 172 Mass. 488, 491. Sullivan v. Marin, 175 Mass. 422. Steverman v. Boston Elevated Railway, 205 Mass. 508, 513. Stynes v. Boston Elevated Railway, 206 Mass. 75. Pearson v. Duane, 4 Wall. 605. Hannibal Railroad v. Swift, 12 Wall. 262. 13 Cyc. 31, and cases cited in n. 78. See also Connors v. Cunard Steamship Co. 204 Mass. 310.

But the plaintiffs were not harmed by this ruling as the previous findings and rulings were decisive of their right to recover. American Malting Co. v. Souther Brewing Co. 194 Mass. 89, 97.

Exceptions overruled.