after stating the case, delivered the opinion of the court.
Instruction No. 14 above is fatally defective.
1. The jury is told that this is an action brought by a third person against a copartnership to enforce a copartnership liability. One of the principal issues raised by the pleadings, and upon which the evidence is in irreconcilable conflict, was whether or not a copartnership- of which the answering defendant was a member had any existence in fact, and, if so-, whether there was any copartnership liability, and, notwithstanding this issue, both questions are determined by the court in its in*506structions, leaving the jury practically nothing to decide. The court ought not to assume the existence of a disputed state of facts.
In Territory v. Scott, 7 Mont. 407, 17 Pac. 627, this court said: “Where the evidence is clear and conclusive as to the existence of the particular fact, and there is evidence to the contrary, or where facts are admitted, an instruction assuming such facts as true will not work a reversal of the judgment; but if there is the least conflict in the evidence, or if the evidence is in any wise of a doubtful character, such ruling will be held erroneous. Caldwell v. Stephens, 57 Mo. 589-595; Barr v. Armstrong, 56 Mo. 577-588.” The rule is the same in civil as in criminal actions. (Collier v. Fitzpatrick, 19 Mont. 562, 48 Pac. 1103 ; Butte & Boston Mining Co. v. Societe Anonyme Des Mines De Lexington, 23 Mont. 177, 58 Pac. 111, 75 Am. St. Rep. 505.)
2. The Code establishes the law of this state respecting the subjects to which it relates. (Political Code, Sec. 4.) Section 3390, Code of Civil Procedure, among other things, provides: “The jury subject to the control of the court in the cases specified in this Code, are the judges of the effect or value of evidence addressed to them, except when it is. declared to be conclusive. They are, however, to be instructed by the court on all proper occasions: * * (5) That in civil cases the affirmative of the issue, must be proved, a.nd when the evidence is contradictory the decision must be made according to the preponderance of the evidence. * * *”
This section, then, is conclusive upon the quantum of evidence required in all such cases, whether it be an action by a third party against a copartnership, or by one partner against another, and the court was entirely wrong in saying that a different rule applies in one case from that in the other.
In an action by one partner against another, the utmost that can be required of the plaintiff is that he show by a fair preponderance of the evidence that the defendant is a member of the copartnership, and in an action by a third party against a *507copartnership nothing less will suffice. The rule is the same in either instance, and the instruction given could hardly fail to' mislead the jury to the prejudice of the answering defendant. In any event, error being apparent, prejudice will be presumed. (State v. Mason, 24 Mont. 340, 61 Pac. 861; Parrin v. Montana Central Ry. Co., 22 Mont. 290, 56 Pac. 315.)
As this cause must be reversed, attention is directed to instruction No. 15, supra. While the instruction, if rightfully understood, correctly states a legal principle, yet, standing alone, it is likely to be misunderstood by a jury, and should not bo given without explanation or elucidation. Instruction No. 16, given, repeats one of the errors found in instruction No-. 14.
We do not consider the question as to whether the complaint states a cause of action, or the question as to- whether the evidence is sufficient to show that an account was ever stated. This latter question, though involved in one of the assignments of error, is not presented by appellant in her brief.
The order appealed from is reversed, and the cause remanded with directions to the lower court to grant the answering defendant a new trial. i
Reversed and remanded.