We are of opinion that the ruling of the learned judge in the court below was erroneous. It does not appear by the bill of exceptions that the defendant in terms objected to the entry of a nolle prosequi, or insisted on a verdict, on the third count; but as the jury found a verdict of not guilty on that count, it is evident that a nolle prosequi was not entered during the trial, and it is to be presumed that the defendant did not assent that it should be done.
Before the jury is empanelled, or after conviction, a nolle prosequi may be entered without the assent of the defendant; but not during the trial. It is then the right of the defendant to have the jury pass upon his case, and he is entitled to a verdict which will be a bar to another indictment for the same offence ; and a nolle prosequi is not a bar. At that stage of the proceedings his consent is necessary. Commonwealth v. Tuck, 20 Pick. 856, 365. Commonwealth v. Kimball, 7 Gray, 328.
The mere offer to enter a nolie prosequi did not therefore limit the trial to the two other counts. The defendant was still on trial upon all the counts, and he had the right to meet any evidence offered by the government in support of the charge in the indictment. The ground upon which the district attorney made this offer is immaterial, as affecting the principle involved. He might do so for any reason in his discretion; he might because he thought the evidence insufficient, and thus discontinue for the purpose of beginning another prosecution, and subjecting the defendant to another trial for the same offence. He would thus deprive the defendant of his right to a verdict, (which would be a bar,) after the trial had begun, and against his consent. Commonwealth v. Tuck, ubi supra.
ISTor do we think that the offer of the district attorney to con-cent to a verdict on this count rendered the evidence offered by the defendant incompetent. When a party is put uj ion trial for *35several offences of a similar character, charged in several counts in one indictment, it is proper for one witness to testify to all the charges, if within his knowledge; and it would be clearly competent for the defendant to contradict the testimony of such witness upon any one count, not only for the purpose of discrediting his testimony on that count, but for the purpose of affecting his general credibility as a witness. The testimony, though relating to different offences, is yet the testimony of one witness, and must, so far as the credibility of the witness is concerned, be necessarily treated as a whole, and be so weighed and considered by the jury. The government having elected to charge and prove the several offences in this manner, anything tending to impeach the credibility of the witness upon any portion of his testimony in chief must, as in other cases, affect his whole testimony.
The defendant was put on trial on all the counts; the testi many of Flynn went to the whole case; the portion applying to the third count, as well as the portions applying to the other counts, was competent when put in, and was still in the case. Having chosen to take this course, and still relying on the testimony of Flynn to sustain the other counts, the prosecuting officer could not debar the defendant from contradicting his testimony in chief in relation to the third count, and thus discrediting his whole testimony, by saying that he would withdraw that charge and assent to a verdict of not guilty on the third count. It would enable him to shield his own witness, perhaps to the serious injury of the defendant.
The evidence is not open to the objection that it related to an immaterial and collateral fact, which upon familiar principles cannot be contradicted.
This case does not present the question raised in Commonwealth v. Cain, 14 Gray, 7. The first count in that indictment charged the defendant with being a common seller from April 1 to August 22. The other counts were for single sales during the time covered by the first count. The fourth count was for a sale on August 22, to Francis Taylor. One Murray testified to sales between April 1 and August 22, and one to himself on August 22, but did not testify to any sale, as charged in the fourth count, to Taylor; and the district attorney stated that *36he did not intend to offer any evidence on that count, and did not. On cross-examination Murray testified to a sale to Taylor on August 22, as charged in the fourth count, and the defendant offered evidence to contradict him on that point; and the court held it was rightly excluded. The evidence of the sale to Taylor was introduced by the defendant on cross-examination. The government had offered no evidence upon that count, and had disclaimed all intention to support the fourth count by proof of any sale on August 22, except the sale to Murray; and any other sale on that day was held to be irrelevant and immaterial to the issue. And it was said by Mr. Justice Metcalf, that “the defendant, by cross-examining Murray as" to any other sale on that day, introduced collateral and immaterial matter, and thereby, in the opinion of a majority of the court, brought himself within the settled rule, that when a question is put to a witness, which is collateral or irrelevant to the issue, his answer cannot, for the purpose of discrediting him, be contradicted by the party who asked the question.” The evidence which the defendant sought to contradict was evidence introduced by himself, and not, as in the case at bar, introduced by the government. It is sufficient to point out this distinction, Without considering the decision of Commonwealth v. Cain more at length.
Exceptions sustained.