After the decision reported as Traverse v. Wing, 256 Mass. 320, this action has been tried to a jury for the second time and is before us upon a bill of exceptions which presents the single question whether there was error in refusing to direct a verdict for the defendant.
The evidence differs in material respects from that which we held required submission to a jury. Any extended discussion of the differences has become unnecessary, in view of the ruling of the judge that the evidence would not justify finding that the plaintiff’s injuries were due to lack of sterility in novocaine used. No objection to this ruling appears to have been made.
The earlier decision held that the evidence that the plaintiff’s injury resulted from the use by the defendant of nonsterile novocaine or an unsterilized instrument, and that such use was negligent, was more than conjecture. No such decision is now possible. There was evidence that the infection, from which the plaintiff suffered, might have been due to unsterilized implements or defective novocaine; but that it was impossible to decide to which of the two it should be attributed. It follows, since unsterile novocaine may have caused the plaintiff’s suffering, and since unsterile novocaine may have been administered without negligence, *529that the defendant’s responsibility is left to conjecture. Morris v. Weene, 258 Mass. 178, and cases cited. Bigwood v. Boston & Northern Street Railway, 209 Mass. 345.
We have examined the evidence set out in the bill of exceptions and are satisfied that the ruling was justified, and that recovery ought not to be permitted on evidence so uncertain and speculative.
The ruling denying the motion was error. Judgment should enter for defendant. G. L. c. 231, § 122.
Exception sustained.
Judgment for defendant.