The board of public education in each school district of the first class shall prescribe the mode or modes of determining the qualifications of applicants for positions as principals or teachers in the schools of the district, and shall designate the kinds or grades of teachers' certificates which may or shall be used in the district, together with the scholastic, professional, and personal qualifications required for each kind or grade of certificate.

No certificate shall be granted to any person who is not of good moral character, or to any person who shall not first have presented a certificate, from a physician recognized by the board of public education as competent for the purpose, setting forth that said applicant is neither mentally nor physically disqualified by reason of tuberculosis, or any other chronic or acute physical impairment, from successfully performing the duties of a teacher.