¶1The statute (see. 2884, R. S.) provides that when the action is against persons jointly liable on a contract, and the summons is served upon some, but not upon all, of the defendants, judgment may be entered in form against all the defendants so jointly indebted, “ so far only as that it may be enforced against the joint property of all and the separate property of the defendant served.” The words of the statute are permissive only, in form. Rut the exercise of a statutory power which' is only permissive in form is not discretionary where public interests or individual rights call for its exercise. In such cases it is peremptory. Cutler v. Howard, 9 Wis. 809; Market Nat. Bank v. Hogan, 21 Wis. 317; Dutcher v. Dutcher, 39 Wis. 651; Suth. Stat. Const. § 462. So, this statute must be held to be mandatory, because the individual right of the defendant served requires it. To enter judgment against the defendant served, only, is not a mere formal error, but it is matter of substance. This was so held in Bacon v. Bicknell, 17 Wis. 523. See, also, Helson v. Bostwick, 5 Hill, 37; Stehr v. Ollbermann, 49 N. J. Law, 633. It changes the form of the execution. It can only go against the separate property of Mitchell; whereas it should go against the joint property of the firm. Mitchell has the right, as between himself and his copartner, that the firm property shall be applied first to the payment of the firm debts. If the execution goes against his separate property alone, it may prejudice him in the collection of the money from his copartner. The proper form of judgment in such case is pointed out in Blackburn v. Sweet, 38 Wis. 578.
¶2By the Court.— The judgment of the circuit court is reversed, and the cause remanded with direction to enter judgment in accordance with this opinion.