The former judgment in the suit for malpractice was on the merits, and is conclusive as to all matters then in issue between these parties. King v. Chase, 15 N. H. 9. The question of malpractice having been thus determined in favor of this plaintiff, it is not open to the defendant to try the same question again in this suit, and he is estopped from setting up in defence what was determined against him by the former judgment. Edwards v. Stewart, 15 Barb. 67; Stevens v. Miller, 13 Gray 283; Bigelow on Estoppels 45.

Judgment for the plaintiff.