The state treasurer is hereby authorized and directed to receive on behalf of the state, and to execute all instruments incidental thereto, federal or other funds to be used for payments of assistance herein provided, and to place all such funds in a special account to the credit of the "state department of public welfare," which said funds shall be expended by the department for the purposes and under the provisions of this chapter, and shall be paid out by the state treasurer as funds appropriated to carry out the provisions of this chapter are paid out by him.