Eminent scientists in all parts of the world have for many years been devoting themselves to the study of crime, its causes and its prevention, and the cultivators of the science of criminology already cover a vast field of research which comprises almost everything under the sun. While some analyze the physiological condition of the individual, his psychology, atavistic and hereditary tendencies, the influence of age and sex on criminality; others observe geographical conditions in order to discover the influence of the atmosphere, of temperature, of the rivers and seas, of agricultural products, of the soil and subsoil of the place where the individual is found and the kind of food he lives on; and, lastly, others study social conditionsin other words, the influence of poverty and wealth, of habits, usages and customs, of vices, of civil status, of education, of professions, etc., on the commission of crimes. And in order to formulate doctrines from the splendid fruits of such studies, their advocates have advanced brilliant theories in order to explain the causes of the social phenomenon called crime. It cannot be said, however, that all questions on criminology have been completely settled. There are still serious objections to some conclusions drawn by criminologists, and the law of criminal saturation, for example, by virtue of which in every social environment there is a minimum of natural and atavistic criminality, due to anthropological factors, is still a mooted question. We are, therefore, in the midst of a period of research and analysis, and by way of contribution to these studies from which civilization and humanity derive so many benefits I propose to explain some more facts, taken from our criminal statistics, in order to point out the causes which in my opinion facilitate the development of certain criminal tendencies. I.