The assistant district attorney shall receive as compensation for his services, in addition to the annual salary paid by the state an annual salary of two thousand two hundred dollars, payable monthly on his own warrant. The additional salary shall be paid by the parishes comprising the Second Judicial District as follows:
By the parish of Claiborne, the sum of six hundred dollars per annum;
By the parish of Bienville, the sum of six hundred dollars per annum;
By the parish of Jackson, the sum of one thousand dollars per annum.