1. The sound film has a number of definite advantages as an adjunct to psychiatric teaching. Selection of case material can be improved, waste of time in teaching hours reduced, discussion can be free without harm to the patient, significant points can be driven home by captions, cutting and reprojecting the film, the whole course of an illness with the changing phases may be telescoped into half an hour, and the sound film can readily be used for instruction at places where the actual clinical material is not available. This may be of special value in military psychiatry, particularly for the instruction of non-commissioned officers at induction stations, and for teaching doctors about war neurosis before their arrival in combat zones.2. In clinical research sound films are a means of preserving transient behavior and talk for analysis on the screen, for comparison of different phases of illness and for comparison of different patients. Selected segments of a patient's life and test situations can be recorded in a wholly objective manner. Some particular benefits derived in a study of aphasia are noted. It is suggested that very important advances can be made in the knowledge of brain function by using sound movies for the exact recording of behavior and speech disorders resulting from cranial injuries occurring in war.