THE root idea in punishment as ordinarily understood is the infliction of some kind of dis-agreeableness, pain, or loss on an individual, because he has been guilty of some misdeed. There are thus two aspects—on one hand the infliction of hurt, on the other hand the relation of this to some wrongdoing or crime. Originally any end to be gained by such infliction was scarcely conscious, if it existed at all—any end, that is to say, beyond the satisfaction of the anger evoked by the misdeed itself. The psychological source is to be found in the anger caused by the wrong. From this primitive source to the modern conception the evolution of theories of punishment, conscious or unconscious, may be said to have passed through four stages or phases. These may be designated the vindictive, the retributive, the protective or deterrent, and the reformatory or curative.