1. Although a suit of this description is usually conducted in the name of the person who *585bolds the office of county treasurer, yet it is really a prosecution at the suit of the county, and when a judgment is given it is for the use of the county, and the individual making the motion, has no pecuniary interest whatever in the prosecution. The statute imposes the duty as one that is official, and it admits of question if costs should be allowed, even if the motion fails. Without deciding more /than the precise point involved, we think it clear the individual was properly allowed to testify that no return had been made to him as the treasurer. [Dig. 146, § 22.]

2. If the treasurer was suing for fees due to himself, as an officer, it might admit of question whether the defendant could not properly question his right to exercise the office, but when his acts in the office affect the rights of third persons, or of the county, we apprehend his title cannot be collaterally called in question. The statutes impose the duty on the clerks of the circuit and county courts, to make returns on oath to the county treasurer, and it is a matter of no importance to them who fills the office, so that it is actually filled, or colorably used. It is possibly true, the acceptance of a temporary appointment to fill a vacancy in the office of clerk of the circuit court rendered it incompatible for the same person to discharge the duties of county treasurer. [Dig. 579, § 22.] But until a successor was appointed in that office, or its vacancy established by some judicial proceeding, it cannot be asserted that the exercise of its 'functions by the plaintiff, was without colorable pretence. Being in the exercise of the office under color of title, it is the uniform current of decision, that his acts would be a protection to third persons, and that his title cannot be collaterally impeached. In Viner’s Abridgement — title, Officer, G, 4— it is said the acts and grants of an officer defacto are good. In McGregor v. Balch, 14 Verm. 428, the attempt was to show a justice of the peace had no jurisdiction because at the same time he exercised the office of post maste. The court considered the offices as incompatible, but decided the question could not be raised in a collateral issue. To the same effect is Mayo v. Stoneum, 2 Ala. Rep. 390; Morrow v. Brady, 7 Ib. 59; McInstry v. Fanner, 9 John. 135; People v. *586Collins, 7 Ib. 549; Fowler v. Beebee, 9 Mass. 231; Backnam v. Ruggles, 15 Ib. 180.

If the acts of an officer de facto are good to protect third persons, the same principle will prevent a stranger from discharging himself from a duty by showing the office illegally or improperly filled, when his duty is to be performed.

We are satisfied the circurt court properly expounded the rule in this case.

Judgment affirmed.