Medical benefits for insured workers: shared provision and costs, contract arrangements and arbitration for excess sickness incidence. The State Government must provide reasonable medical, surgical and obstetric treatment to insured persons and their families; the Corporation may enter into agreements with State Governments, local authorities, private bodies or practitioners on the nature, scale and terms of such medical treatment, may establish and maintain hospitals and services, and may share or waive costs relating to excess sickness benefit incidence. Absent agreement, an arbitrator appointed by the Central Government determines treatment scope and cost sharing. The Corporation may assume provision responsibility in a State subject to agreed cost sharing, and where it provides medical benefit the Central Government is the appropriate Government.