Argued November 8, 1926. The second assignment of error was withdrawn on *Page 271 the argument of this appeal. This leaves only the first, to wit, that the court erred in refusing to allow the defendant to ask the prosecuting witness on cross-examination whether he had not instituted a civil action in trespass against the defendant.
Technically, the question should have been permitted; for it is always competent for a party, against whom a witness is called and gives evidence, to propound such questions, on cross-examination, as may tend to show his interest, bias or feeling in the case: Ott v. Houghton, 30 Pa. 451; Com. v. Farrell, 187 Pa. 408, 423; Com. v. Norris, 87 Pa. Super. 66,70. We agree, however, with the lower court that in this case it was harmless error. The rule is most generally applied to witnesses who are not parties to the litigation; it was established when parties in interest were not competent witnesses. See Cameron v. Montgomery, 13 S. R. 127; Bennett v. Hethington, 16 S. R. 193, and Ott v. Houghton, supra. The purpose is to affect the witness's credibility by showing his interest, bias or feeling in the case. The prosecuting witness had testified fully to the circumstances leading up to the assault on him by the defendant and to the serious beating, cuts and wounds which he had received at the latter's hands; and the gravity of his injuries had been shown by the evidence of the attending physician. The jury could have had no doubt as to his interest, bias or feeling against the defendant. Evidence of the institution of a civil suit for damages could scarcely have affected it; for it is well established that the record of this conviction cannot be offered in evidence by the plaintiff in the civil suit against the defendant: Porter v. Seiler, 23 Pa. 424,431; Bennett v. Fulmer, 49 Pa. 155; Hutchinson v. Bank, 41 Pa. 42; Summers v. Bergner Brewing Co., 143 Pa. 114; Wingrove v. Central Penna Traction Co., 237 Pa. 549. See 31 A.L.R. 262-277. It could only be offered by the defendant himself in possible *Page 272 mitigation of damages: Porter v. Seiler, supra; Rhodes v. Rodgers, 151 Pa. 634, 638. Not even a criminal case should be reversed where an error on the trial has done the defendant no harm. We are satisfied that such is the case here.
The judgment is affirmed.