1. The question raised by the motion in arrest of judgment is, whether the court of common pleas has jurisdiction of this case at this time. By the St. of 1858, c. 45, § 1, the police courts in the several counties “ shall have concurrent jurisdiction, with the court of common pleas and municipal court of the city of Boston,” of all offences which may be punished by a fine not exceeding one hundred dollars, or imprisonment not exceeding one year, or both. By § 2 of the same statute, “ the several justices of the peace authorized to hear and determine criminal cases shall within their several counties have jurisdiction” of all offences which may be punished by fine not exceeding fifty dollars, or imprisonment not exceeding six months, or both. It is contended that the word “ concurrent” being omitted in § 2, justices of the peace have exclusive jurisdiction. It is immaterial whether it was omitted by amendment or not. Taking the language of the statute as it is, what is the effect of this section ? Before this statute the *66court of common pleas had jurisdiction over this subject matter. Is that jurisdiction taken away ? It is no answer to say that another tribunal has jurisdiction ; for that is very common. It is in such case concurrent jurisdiction, whether so called in the statute or not. Then is the jurisdiction of the court of common pleas, which it had before, taken away ? There must be words of limitation to take it away, either by using the word “ exclusive,” or by repealing the former act giving jurisdiction, by which it may appear that the legislature meant not only to confer jurisdiction on justices of the peace, but also to take away the other jurisdiction. Here are no words indicating that it should be exclusive, nor repealing any specific statute. There is in § 4 a clause repealing all acts or parts of acts inconsistent with the provisions of this act; but that is no more than would have been the effect without it. If the legislature has passed an act which is inconsistent with a prior law, it does repeal it We do not mean to say that it is not well to enact such a provision. One great purpose of legislation is not merely to establish law, but to establish it so clearly that there shall be no doubt about it, and, as litigation itself is an evil, therefore to use such clearness of language as shall avoid litigation or doubt. For myself, I have no hesitation in saying that, had the word “ concurrent ” been omitted in the first section, the construction would have been the same. Taking the reason of the thing, apart from the words, the statute contemplates police courts as of a somewhat higher character than justices of the peace. Could it have intended to say that the jurisdiction of a justice of the peace should be exclusive, when the higher jurisdiction of a police court was not so ? We are of opinion that the St. of 1858 gave a concurrent jurisdiction only to justices of the peace, and did not oust the jurisdiction of the court of common pleas by indictment.
2. Another question is of great importance in practice. The district attorney called a witness, and thereby undertook that, so far as he knew, he was entitled to credit, and held him up to the court and jury as a credible witness. Can he afterwards impeach him 1 Sometimes the attorney may be disappointed. The witness may even have told him that he would testify that *67way, and courts in such case are inclined to allow him to disparage the witness, but the general rule is that he must not. Here the district attorney must have known that he testified before the grand jury; but we do not put it on that ground. The attempt is not to prove the fact which he testified to before the grand jury. It can only be to disparage him by showing that he testified differently. The whole course of practice is otherwise in this commonwealth. A witness, when called by one party, is liable to be examined and bound to answer as to all facts material to the case, whether examined upon that subject by the party calling him or not. It is said the defendant, by calling the witness again, makes him his own witness to all purposes. He does to some purposes ; it would be very difficult to determine what. But the party who first called him cannot be allowed to say or to show that he was unworthy of credit.
Exceptions sustained.