T HERE are many conditions which may make it difficult for a patient to breathe. Some of them, such as poliomyelitis and certain neurological conditions, may cause a paralysis of the respiratory muscles, and the patient's life depends on mechanical respiratory aids. This does not mean, however, that he must spend the rest of his life in a tank respirator. New devices and improved methods of medical and nursing care have made it possible for such a patient to become less dependent on the tank respirator which restricts his activities.