This is the first of several papers which will be concerned with various branches of the health services. The object of these papers will be fourfold: 1. To describe the service and attempt an evaluation of its costs and benefits. 2 .To compare the service with those of other countries. 3. To ascertain whether changes in the organisation of the service might increase the benefit it renders without appreciably increasing costs. 4. To assess the benefits which might be obtained if increased expenditure were to be devoted to the service.