TY - JOUR T1 - THe potency of digitalis standardized according to u. s. p. xi AU - Wright HN Y1 - 1939/03/25 N1 - 10.1001/jama.1939.02800120066022 JO - Journal of the American Medical Association SP - 1180 EP - 1180 VL - 112 IS - 12 N2 - To the Editor:—  There appears to be a growing confusion among physicians and others with regard to the changed relationships in the standardization and dosages of digitalis preparations made according to the requirements of U. S. P. XI as compared with those of U. S. P. X.All U. S. P. digitalis preparations manufactured prior to June 1, 1936, were standardized according to U. S. P. X. Practically all clinical articles published between 1926 and 1938 are based on the administration of U. S. P. X standardized digitalis. U. S. P. X required all official digitalis preparations to be standardized on frogs by the one hour progressive dose method and to be adjusted to a toxicity of 0.006 cc. (range 0.0055-0.0065 cc.) of tincture per gram of frog or, in everyday language, the equivalent of 600 mg. (range 550-650 mg.) of standard digitalis leaf per kilogram of frog.Digitalis preparations SN - 0002-9955 M3 - doi: 10.1001/jama.1939.02800120066022 UR - http://dx.doi.org/10.1001/jama.1939.02800120066022 ER -