The defendant was tried for assault with a dangerous weapon. A witness called by the Commonwealth, who had given material testimony based on his presence near the place of the alleged assault at about the *542time it occurred, testified on cross-examination that he was arrested by the defendant at that time for violation of the automobile law. Subject to the defendant’s exception, he was allowed to testify on redirect examination that upon the hearing in the District Court on the charge on which he was arrested by the defendant he was discharged. The action of the District Court under the circumstances here disclosed was susceptible of proof only by its records or copy thereof. Sayles v. Briggs, 4 Met. 421. Smith v. Kirby, 10 Met. 150, 154. Wells v. Stevens, 2 Gray, 115. Commonwealth v. Walsh, 196 Mass. 369. Commonwealth v. Danton, 243 Mass. 552. The excepted evidence related to a material matter, and its admission cannot be regarded as harmless error. It is unnecessary to consider the other exceptions.
Exceptions sustained.