PREPARATIONS for dealing with casualties in the event of war are now well advanced. The Ministry of Health has issued circulars to local and other authorities under the Air-Raid Precautions Act, 1937, indicating the organization of emergency ambulance services, and of first-aid posts (Circulars 1787 and 1789. H.M. Stationery Office. 2d. and 3d. net, respectively). An emergency Hospitals Scheme for London has also been prepared. This scheme is based on the affiliation of certain casualty hospitals in the more vulnerable areas to others in outer areas. In London this affiliation is arranged in ten sectors radiating from the centre. Each of these sectors contains voluntary and municipal hospitals of widely differing types, including the great teaching hospitals, local authority institutions, mental hospitals, specialized hospitals, cottage hospitals, and others. It is proposed that the casualty hospitals near the centre of each sector should be used so far as possible for immediate treatment only, and that the injured should be transferred at the earliest opportunity from the centre to affiliated casualty base hospitals in the outer areas.