Every one who has used spinal anesthesia for any considerable period is impressed with two facts: first, that it is a wonderfully satisfactory anesthesia for urologic cases, and, second, that there often occurs a marked depressive effect during and after the anesthesia which cannot be accounted for by the operation alone and which constitutes an element of grave danger. It is perhaps well understood that this element of danger is due to the marked fall in blood pressure that takes place. We conceived the idea that the best way to combat this untoward effect of spinal anesthesia was to devise a means of sustaining the blood pressure throughout the period of anesthesia. In this connection we called to mind what Major and Stevenson1had pointed out regarding the blood pressure raising qualities of methyl guanidine, but we were rather afraid to use so toxic a substance since it had