We, therefore, conclude that it was the purpose of the legislature to confer upon the probate court exclusive original jurisdiction over the appointment of guardians — a conclusion which appears to be implicit if not expressed in the case of Brooks v. Brooks, 77 N.H. 547. In the light of the foregoing discussion, it is plain that the dictum of Bellows, J. in State v. Richardson, 40 N.H. 272, 273, that "in this State a court of chancery has probably a like power, [to appoint guardians] notwithstanding the jurisdiction conferred upon the probate court to appoint guardians `whenever there shall be occasion'," which was repeated in Prime v. Foote, 63 N.H. 52, 53, must be regarded as erroneous. It is, of course, true that questions of custody may come before the superior court in habeas corpus proceedings, and in such a case the court must determine whether the child's welfare will be best promoted by a change in custody.

But if he is suitable, no reason exists for his removal from the trust, and there is no occasion for the appointment of some other suitable person. Newton v. Janvrin, 62 N.H. 440; Prime v. Foote, 63 N.H. 52; P. S., c. 178, s. 1. In 1911, the natural guardianship possessed by the father was extended to include the mother by an act of the legislature constituting her a joint guardian with the father of the persons of their minor children, with equal powers, rights, and duties.

It is true that at common law the father is the natural guardian of his minor child, and because of this his domicile is the domicile of the child. State v. Richardson, 40 N.H. 272, 273; Prime v. Foote, 63 N.H. 52. But in 1911, when all the parties resided in this state and were domiciled here, the common law upon this subject was changed by an act of the legislature constituting the mother a joint guardian with the father of their minor children, with equal powers, rights, and duties. Laws 1911, c. 104, ss. 1, 2.