When the council shall decide that it is to the best interest of the municipality that the duties in this code designated to be performed by the treasurer should be done and performed by the clerk of such municipality, they may at their option, by resolution, duly presented and approved by such council assign such duties to the clerk of such municipality; provided, that the duty of receiving any funds collected by the clerk and the depositing and disbursing of such funds by order of the council shall always be and remain the duty and responsibility of the treasurer; the council shall, in said resolution, devise a proper system or plan whereby the clerk may pay to the treasurer all moneys collected by him and take receipts therefor.