The president of the county board shall at the first regular meeting of the first day after July, A. D. 1895, appoint three persons, who shall constitute and be known as the civil service commission of said county; one for a term ending on the first Monday of December, A. D. 1895; one for a term ending on the first Monday of December, A. D. 1896; one ending on the first Monday of December, A. D. 1897, and until their respective successors are appointed and qualified. And at the respective dates above named, or soon thereafter, the president shall in like manner appoint one person as the successor, or a commission, whose term shall then expire, to serve as a commissioner for three years, and until his successor is in like manner appointed and qualified. Two commissioners shall constitute a quorum. All appointments to such commission, both original and to fill vacancies, shall be so made that not more than two members shall at the time of appointment be members of the same political party. Said commissioner shall hold no other lucrative office or employment under the United States, the State of Illinois, or any municipal corporation or political division thereof. Each commissioner, before entering upon the duties of his office, shall take the oath prescribed by the Constitution of this State.