Are patents for methods of medical treatment contrary to the ordre public and morality or 'generally inconvenient'?

'No one has advanced a just and logical reason why reward for service to the public should be extended to the inventor of a mechanical toy and denied to the genius whose patience, foresight, and effort have given a valuable new [discovery] to mankind' (Katopis CJ. Patents v patents: policy implications of recent patent legislation. St John's Law Review 1997;71:329). The law around the world permits the granting of patents for drugs, medical devices, and cosmetic treatment of the human body. At the same time, patentability for a method of treatment of the same body is denied in some countries on various public policy grounds. Is there any logical justification for this distinction? Are methods of medical treatment not as vital to the health or even to the life of a patient as drugs or medical devices? Why is a cosmetic result patentable and a curative result not?