The board of chosen freeholders shall file with the commissioner certified copies of all bills. Payment to the board shall be made of the state‘s share of the costs of operation and repair from the amount set aside as hereinbefore provided, on certificate of the commissioner attached to the copies of bills, setting forth the amount of the share and the fact that the work described therein has been properly done, but the share assumed by the state shall not exceed thirty-three and one-third per cent.

Nothing herein contained shall authorize the payment as the state’s share of the cost of operation and repair of an amount in excess of the sum set aside for that purpose.