Dosage of liver extracts used in the treatment of pernicious anemia has been discussed at length and no longer presents a serious problem. What the time interval between injections of liver extract should be has scarcely been studied. The present availability of highly concentrated liver extracts for general use in the treatment of pernicious anemia makes this problem one of considerable practical importance. One can easily inject at one time as many U. S. P. units of liver extract as have been found necessary for maintenance over a period of from six to twelve months when given in divided doses at frequent intervals. Such a procedure, although it may produce temporary local discomfort, would be convenient for the patient and would save considerable time. A study of four patients by Miller1in 1936 suggested the feasibility of such a method of treatment, and observations made by several members of