This manual, prepared for the guidance of the house staff of the Los Angeles County Hospital, has been completely revised since the publication of the second edition in 1941. It is abreast of modern practice and is sufficiently comprehensive to cover the essential needs in relation to general rules and regulations, minor technical procedures, the hospital formulary, diet outlines, laboratory procedures and other departmental routines. These standardized procedures should prove exceedingly helpful to new house officers, who must necessarily consolidate and systematize their knowledge in order to function efficiently in a complex hospital organization. Directive outlines are included with reference to physical therapy, radiation therapy, general medicine, contagious diseases, pediatrics, neuromedicine, neurosurgery, general surgery, anesthesia, urology, orthopedics, fractures, gynecology, obstetrics, dermatology-syphilology, ophthalmology and otolaryngology. There are special sections on sulfonamide therapy, war gases, burns, immunization procedures, public health regulations and psychiatric studies. Full directions of diagnostic and therapeutic methods are