Guardians of the property of minors must prosecute and defend for their wards. They must also in other respects manage their interests under the direction of the court. They may thus lease their lands or loan their money during their minority, and may do all other acts which the court may deem for the benefit of the ward. [§3441.] All power of the guardian over the estate of his ward is derived from the appointment of the court, but an appointment as guardian will not authorize a sale of property, nor an investment or disposal of money belonging to the ward, without a special order of the court. All expenses for the education and maintenance of the ward must be kept within the income of his estate. If this should not be sufficient the principal may be resorted to, but not without an order of the court. All transactions between guardian and ward, where the former has secured an apparent advantage, by way of gift, or contract or settlement, will be presumed to have been the result of undue influence, and will be set aside by a court of equity, unless it can be shown that they were made in good faith and for a fair and valuable consideration. [Sidenote: Property in state.] The foreign guardian of any non-resident minor, may be appointed the guardian in this state of such minor, by the district court of the county wherein he has any property, for the purpose of selling or otherwise controlling that and all other property of such minor within the state, unless a guardian has previously been appointed under the preceding section. The foreign guardian of any non-resident idiot, lunatic or person of unsound mind may be appointed the guardian of such ward by the district court in like manner and with like effect in all cases where the foreign guardian of a non-resident minor could be appointed the guardian of such minor in this state. Such guardian shall have the same powers and be subject to the same liabilities as guardians of resident minors. [§3457.] [Sidenote: Guardians of drunkards, spendthrifts and lunatics.] When a petition is presented to the district court, verified by affidavit, that any inhabitant of the county is: 1. An idiot, lunatic, or person of unsound mind; 2. An habitual drunkard incapable of managing his affairs; 3. A spendthrift who is squandering his property, and the allegations of the petition have been satisfactorily proved upon the trial, such court may appoint a guardian of the property of any such person, who shall be the guardian of the minor children of his ward, unless the court otherwise orders. Such court may also appoint the guardian of the property of an habitual drunkard as the guardian of his person. If the person adjudged to be an habitual drunkard has no property, the court may appoint a guardian of his person. [§3463 Sup.] [Sidenote: Order for restraint of drunkard.]