¶1There was a mistrial of this case. A declaration in set-off having been filed, the plaintiffs could not discontinue without the consent of the defendant. Gen. Sts. e. 130, § 21. If the defendant had not consented to it, there was no valid discontinuance, and the plaintiffs were entitled to proceed on all the counts of their declaration. If the defendant had consented to a discontinuance of the plaintiffs’ counts in contract, he should not have been permitted to introduce evidence of his set-off. It was for the judge before whom the action was tried to determine whether there had or had not been a valid discontinuance. But the rulings at the trial allowed the defendant to affirm the discontinuance so far as it restricted the claim of the plaintiffs, and to re ■ pudiate it so far as it affected his own.
¶2Exceptions sustained.