If these statements be correct, why should not animals be held penally responsible for their conduct as well as human beings? There are men apparently less intelligent than apes. Why then should the man be capitally punished and the ape not brought to trial? And if the ape be made responsible and punishable, why not the dog, the horse, the pig, and the cat? In other words, does evolutionary criminology justify the judicial proceedings instituted by mediæval courts against animals or regard the typical human criminal as having in this respect no supremacy over the beast? Does modern science take us back to the barbarities of the Middle Ages in matters of penal legislation, and in abolishing judicial procedure against quadrupedal beasts is it thereby logically forced to stay the hand of justice uplifted against bipedal brutes? The answer to these questions is unhesitatingly negative. Zoöpsychology is the key to anthropopsychology and enables us to get a clearer conception of the genesis of human crime by studying its manifestations in the lower creation; we thus see it in the process of becoming, acquire a more correct appreciation of its nature and origin and learn how to deal with it more rationally and effectively in bestial man. Another point discussed by Plato and still seriously debated by writers on criminal jurisprudence is whether punishment is to be inflicted _quia peccatum est_ or _ne peccetur_; in other words, whether the object of it should be retributive or preventive. The truth is, however, that both of these motives are operative and as determining causes are so closely intermixed that it is impossible to separate them. As the distinguished criminalist, Professor Von Liszt, has remarked one might as well ask whether a sick man takes medicine because he is ill or in order to get well. The penalty is imposed in consequence of the commission of a crime and also for the purpose of preventing a recurrence of it, and is therefore both retributory and reformatory. Punishment is defined by Laas as “ethicized and nationalized revenge, exercised by the state or body politic, which is alone impartial enough to pronounce just judgments and powerful enough to execute them.” Civilization takes vengeance out of the hands of the injured individual and delegates it to the community or commonwealth, which has been outraged in his person. The underlying principle, however, is, in both cases, the same, and the idea of justice, as administered by the community, does not rise above that entertained by the aggregate or average of individuals composing it.