special knowledge of any language used in the Philippine Islands may receive additional compensation for such kno wledge at not to exceed one hundred pesos per annum for each such language. [2468-17.] S ECTION  777 . Grade of Original Appointments. —  Except as provided in the next succeeding paragraph hereof, no original appointment in the commissioned service shall be made above the grade of surgeon. cHITCS If the Director of Health finds that a necessity exists for special expert services in the commissioned service, and, with the approval of the Secretary of the Interior, certifies that no physician or surgeon then in the service possesses the requisite spe cial qualifications, an original limited appointment may be given by the Governor-General for a period of four years or less, to any physician or surgeon upon his having been examined and approved by the Bureau of Civil Service if a resident of the Philipp ine Islands, or by the Civil Service of the United States if a resident of the United States. [2468-20.] S ECTION  778 . Promotions. — A vacancy in any grade in the commissioned service shall be filled by promotion from the grade next below that of the position in question. Two-thirds of all promotions to such vacancies shall be made by seniority and one-third by  selection. [2468-23.] S ECTION  779 . Promotion of Surgeon. — A surgeon, passing the requisite examination, shall be entitled to promotion to the next higher grade after three years' service, and in making this computation time served in any medical capacity under the Government o ther than as interne shall be counted. [2468-23.] S ECTION  780 . Examination Requirement. — No officer shall be appointed to any position in the commissioned service or promoted to any higher grade therein unless he shall have passed the requisite civil-service examination. [2468-23-25.] All examinations for appointment and promotion shall be thorough and shall include physical, moral and professional qualifications. It shall cover such subjects as the Director of Health may prescribe and be conducted in such manner Copyright 2012 CD Technologies Asia, Inc. and Accesslaw, Inc. Philippine Law Encyclopedia 2011 238