A METHOD FOR THE BlO-ASSAY OF DIGITALIS IN HUMANS

Evidence has accumulated in recent years which indicates that animal methods for the assay of digitalis and its glycosides give results which may be misleading when applied to humans (1). It has been shown that the frog method has serious defects in this respect, since a specimen which has the same activity as another when compared in humans, may be only half as strong as the other when com-pared in frogs. In these studies the results of the cat method proved to be a more reliable index of the relative potency of digitalis preparations in man, but defects of the cat method were also pointed out. In the past two years we have explored the possibilities of using human subjects for the assay of digitalis. The present report deals with a description of a satisfactory human method of assay which has been developed in the course of these studies. Attempts have been made in the past to compare digitalis preparations in humans directly, but these have been for the most part abortive. Pardee (2) suggested the use of the T-wave of the electrocardiogram as a measure of digitalis action in humans, and the minimal dose necessary to produce a distinct lowerin