Recently Twycross (28) undertook a comparison in which he crossed 146 patients with cancer pain from morphine to diamorphine, or vice versa, according to a fixed dose ratio. Women reported no difference in pain relief, but men reported increased pain and depressed mood when receiving heroin. Twycross (29) concluded that even though he had not satisfactorily established the equivalent analgesic dose of the two drugs, morphine represented a satisfactory substitute for heroin. His findings were confirmed by Mount, Ajemian, and Scott (30), who substituted morphine in Brompton's mixture and found it as effective as the heroincontaining elixor.