THE DIAGNOSIS, study, and treatment of an increasing number of diseases of infancy and childhood are dependent upon the reliable collection of the total 24-hour excretion of urine. Serial collections are often necessary for prolonged periods of time. In the Endocrine Clinic of the Harriet Lane Home a large number of infants with the adrenogenital syndrome have been studied for periods ranging from several weeks to 522 days without interruption of the urine collections and without adversely affecting the welfare of the infants.