The department shall have the power, and its duty shall be, whenever the General Assembly shall have specifically appropriated money to the department for the purpose, to issue requisitions upon the Auditor General for warrants, to be drawn by the Auditor General upon the State Treasurer, in favor of such hospitals, homes and institutions as shall conform to at least the minimum standards of plant, equipment, service, administration and care and treatment necessary for the proper care and treatment of patients or inmates, as required by the rules and regulations of the department, or established by law, in amounts computed upon the per diem rates of payment established by law for free care and treatment to indigent, sick, injured or crippled persons.