As there is still considerable hesitancy in the adoption of this valuable form of therapy, I am glad to have an opportunity of stating the case for a more widespread application of prolonged narcosis to the manic-depressive disorders. A legitimate diversity of opinion exists as to the propriety of using any drug with a toxic action over a long period, especially so when it introduces an extraneous, and maybe serious, risk into a disease of itself non-fatal, and with a large recovery-rate. With attention to detail in the treatment, and with the addition of the Cardiff modification of prolonged narcosis, we are satisfied that toxic symptoms arising during the administration of somnifaine—the drug used—can be controlled, and the risk heretofore associated with this form of therapy eliminated.