No assignment of, or order for, wages or salary is valid unless made in writing by the person by whom the said wages or salary are earned and no assignment of, or order for, wages or salary made by a married person is valid unless the written consent of the husband or wife of the person making such assignment or order is attached to such assignment or order. No assignment of, or order for, wages or salary of a minor is valid unless the written consent of a parent or the guardian of such minor is attached to such order or assignment. No assignment of, or order for, wages or salary is valid for more than twenty-five per cent of the earnings, wages, or salary of any married person. No such assignment is valid for more than fifty per cent of the earnings, wages, or salary of any unmarried person.

Assignments of wages have priority as to each other from the time they are filed with the employer of the assignor, and the balance due any married person after twenty-five per cent has been so assigned, or due any unmarried person after fifty per cent has been so assigned is not subject to further assignment.