Whenever the Adjutant General shall be absent from the state on active service in the armed forces of the United States for more than thirty days, including attendance at service schools, his term of office shall not expire, and the Governor may appoint an acting Adjutant General for the period of such absence. The acting Adjutant General shall be chosen from among the officers or former officers of the active National Guard and shall have the same powers and duties as the Adjutant General. He shall be compensated for his services at the same rate provided by law for the pay of the Adjutant General, and during the period in office of such acting Adjutant General, the Adjutant General shall not be entitled to and shall not be paid any salary or other compensation by the state.