Mississippi Code Title 33. Military Affairs § 33-7-107

Every person commissioned as an officer in the Mississippi National Guard shall, unless otherwise specifically provided by law, be examined as to his qualifications for office, and no person shall be appointed until he has passed a satisfactory examination as to his capacity, general qualifications and knowledge of military affairs proportionate to the requirements of the office to which he has been selected. The Commander in Chief may appoint examining boards to conduct such examinations, and when any candidate for commission shall fail to appear before a board, as directed, he shall be considered to have failed to qualify and the commission will not issue. The Commander in Chief may also convene examining boards to determine the fitness of officers for promotion and no officer will be promoted who has not passed a suitable examination as to his capacity, general qualifications and knowledge of military affairs proportionate to the requirements of the grade to which he is promoted. The Adjutant General shall prescribe in orders the subjects to be covered by, and the degree of proficiency to be required in each subject in examinations for commissions and promotions, for each grade, and the Governor shall make and cause to be published in orders, regulations governing the promotion of officers.