The salaries fixed by this chapter shall be full compensation for all county officials, deputies, clerks, and assistants, respectively, and all fees and compensation received by any official, deputy, clerk, or assistant for any act or service rendered in an official capacity shall be accounted for and paid over monthly to the county treasurer and be credited to the general fund of said county, except that such official, deputy, clerk, and assistant shall be entitled to retain such fees as now are allowed to that officer and permitted by law or as may be hereafter permitted and allowed.