I. THE RATE OF DISAPPEARANCE OF DIGITALIS FROM THE BODY When we try to maintain a patient under the full therapeutic effect of digitalis, we have always been handicapped by the fact that we do not know the rate at which the body can dispose of this substance by excretion or destruction. It seems likely from recent researches by Hatcher and Eggleston that both of these processes occur.1 The patient is either liable to pass gradually out from under the influence when too small a dose is given, or with overadministration of the drug to have a series of vomiting spells which give the impression that the patient is especially susceptible to the vomiting. It is evident that animal experiment would not give a definite answer to the question of the rate of disappearance of the drug, because of the marked variations that were found between different species. The