Sodium amytal (sodium-isoamylethylbarbituric acid) has been used in psychiatry for several purposes; its uses in producing lucid intervals in catatonia are acknowledged (Bleckwenn). Broder employed it for the first time in continuous narcosis; and later, in combination with caffeine, he used it for therapeutic purposes in the treatment of psychoses; Harris, Horowitz and Milch discovered its prognostic value in insulin and cardiazol therapy, and Hermann, its effects in clearing psychogenic amnesias. It gradually lost its interest from the research point of view because sodium amytal (S.A.) appeared to be similar in results to ordinary hypnosis, but in the course of our own observations we found definite differences between the two.