Hence their teaching and their propositions have had no weight with legislators, for these latter had not been convinced, as only the criminal sociologist could convince them, that punishments are far from having the deterrent force commonly attributed to them, and that crime is not the outcome of free will, but rather a natural phenomenon which can only disappear or diminish when its natural factors are eliminated. The legislators for their part have not only neglected the definite teaching of these authors with more than ordinary insight, but they have also enacted what are <p 141>really penal substitutes in a clumsy and unscientific manner. We have thus studied the data of criminal statistics in their theoretical and practical relations with criminal sociology, and come to the conclusion that, since crime is a natural phenomenon, determined by factors of three kinds, it answers on that account to a law of criminal saturation, whereby the physical and social environment, aided by individual tendencies, hereditary or acquired, and by occasional impulses, necessarily determine the extent of crime in every age and country, both in quantity and quality. That is to say, the criminality of a nation is influenced in the natural sphere by the bio-psychical conditions of individuals and their physical environment, and, in the social sphere, by economic, political, administrative and civil conditions of laws, far more than by the penal code. Nevertheless the execution of punishment, though it is the less important part of the function of social defence, which should be carried out in harmony with the other functions of society, is always the last and inevitable auxiliary. And this entirely agrees with the universal law of evolution, in virtue of which, amidst the variation of animal and social organisms, antecedent forms are not wholly eliminated, but continue as the basis of the forms which succeed them. So that if the future evolution of the social administration of defence against crime is to consist in the development of the primitive forms of direct physical coercion into the higher forms of indirect psychical discipline of human activity, this <p 142>will not imply that the primitive forms must entirely disappear, especially for the gravest crimes, which, in the biological and psychological conditions of those who commit them, take us back to the primitive epochs and forms of individual and social violence.