THE morphine molecule contains five asymmetric carbon atoms and five interlocking ring systems, and constitutes a complicated three-dimensional structure the stereochemistry of which has recently attracted considerable interest. The initial suggestions of Schopf1 concerning the relative orientations at the asymmetric carbons 5, 9, 13 and 14 were extended by Fieser and Fieser2 to include carbon 6, and in terms of these deductions morphine has structure I or its mirror image. Further evidence leading independently to the same conclusion has been found3 by Dr. H. L. Holmes of the Riker Institute, Los Angeles, and confirmation of the relative configurations shown at carbons 5, 6, 9 and 13 has been provided by Rapoport and Payne4. However, up to the present, it has not been possible to decide whether structure I represents morphine or its enantiomorph.