It shall be lawful for any justice of the peace, magistrate or judge of any court, to commit minors to any society, duly incorporated, having for one of its objects the protection of children from cruelty, or the placing of children not otherwise provided for in families, upon complaint and due proof made of facts such as are set forth in the first section of this act, after the said minors have been duly convicted of any criminal offense.
11 P.S. § 28