This is the same case as that of the imaginary physician who says: "You have heart trouble? Then take a quart of rhubarb decoction and stay twelve days in the hospital." Another patient says: "I have broken my leg." And the doctor: "All right, take a pint of rhubarb decoction and 17 days in the hospital." A third has inflammation of the lungs, and the doctor prescribes three quarts of rhubarb decoction and three months in the hospital. "But if my inflammation is cured before that time?" "No matter," says the doctor, "you stay in three months." "But if I am not cured of my lung trouble after three months?" "No matter," says the doctor, "you leave after three months." To such results have wise men been led by a system of penal justice, which is a denial of all elementary common sense. They have forgotten the personality of the criminal and occupied themselves exclusively with crime as an abstract juristic phenomenon. In the same manner, the old style medicine occupied itself with disease as such, as an abstract pathological phenomenon, without taking into account the personality of the patient. The ancient physicians did not consider whether a patient was well or ill nourished, young or old, strong or weak, nervous or fullblooded. They cured fever as fever, pleurisy as pleurisy. Modern medicine, on the other hand, declares that disease must be studied in the living person of the patient. And the same disease may require different treatment, if the condition of the patient is different. Criminal justice has taken the same historical course of development as medicine. The classic school of criminology is still in the same stage, in which medicine was before the middle of the 19th century. It deals with theft, murder, fraud, as such. But that which claims so much of the attention of society has been forgotten by the classic school. For that school has forgotten to study the murderer, the thief, the forger, and without that study their crimes cannot be understood. Crime is one of the conditions required for the study of the criminal. But, the same crime may require the application of different remedies to the personalities of different criminals, according to the different anthropological and social conditions of the various criminals. There is a fundamental distinction between the anthropological and social types of criminals, whom I have divided into five categories, which are today unanimously accepted by criminalist anthropologists, since the Geneva congress offered an opportunity to explain the misapprehension which led some foreign scientists to believe that the Italian school regarded one of these types (the born criminal) merely as an organic anomaly. Just a word concerning each one of these five types.