The general assembly shall annually appropriate any sum that it may deem necessary, out of any money in the treasury not otherwise appropriated, to be expended by the department of children, youth and families for the purpose of preventing cruelty to children, and the department may, in its discretion, pay the sum to the Children’s Friend and Service for that purpose, and the state controller is authorized and directed to draw his or her orders upon the general treasurer for the payment of the sum or so much of it as may be required upon receipt by the state controller of proper vouchers approved by the director of the department.