“…The only major modification to the method of ~l~~~~~ et al (1955) was omission of the permanganate wash. Recent work by Klopper (1955), completed after we had begun our investigation indicates that this step is necessary in the case of non-pregnant urines, and, though desirable in pregnancy, is not essential for the In Cases 1-5 (Table 11) duplicate samples of urine were taken, each being one-twentieth of the 24-hour volume; these provided sufficient material for tests of purity on the final extract in additioll to the normal assay. In Cases 6-10 (Table 11) pregnanediol assays only were carried out for which a smaller quantity of urine (1 /25Oth) was taken.…”