As a matter of fact, when we follow the periodic variations of crime, with its measured growth and decrease, we cannot fail to conclude that these constant and constantly occurring variations depend upon a corresponding variation of anthropological and physical factors. For, whilst criminal statistics are far from showing the regularity which Quetelet claimed with much exaggeration, the proportional figures in regard to the bearings of age, sex, calling, &c., upon criminality exhibit very insignificant variations from year to year. And as for the physical factors, if marked variations are explicable at some given period, it is nevertheless evident that neither climate, nor the nature of the soil, nor atmospheric conditions, nor the seasons, nor the temperature of different years could have undergone in the last half-<p 62>century such constant and repeated variations as to correspond to those waves of criminality which we shall presently exhibit in almost every nation of Europe. Thus it is to the social factors that we must chiefly attribute the periodic variations of criminality. For even the variations which can be detected in certain anthropological factors, like the influences of age and sex upon crime, and the more or less marked outbreak of anti-social and pathological tendencies, depend in their turn upon social factors, such as the protection accorded to abandoned infants, the participation of women in non-domestic, commercial and industrial life, preventive and repressive measures, and the like. And again, since the social factors have special import in occasional crime, and crime by acquired habit, and since these are the most numerous sections of crime as a whole, it is clear that the periodic movement of crime must be attributed in the main to the social factors. So true is this, that, as we shall presently see, the gravest crimes, especially against persons, precisely because they mostly indicate congenital criminality, follow a more steady and regular movement than these slighter but far more frequent offences against property, public order, and persons, of a more occasional character, and that, as microbes of the world of crime, they are the more direct outcome of social environment. It is therefore another point in favour of the experimental school that it has insisted on this sociological aspect of the problem of criminality, by showing <p 63>legislators, outside the limits of their punitive remedies, as easy as they are illusory, how they might, as far as circumstances will permit, apply a genuine social remedy to crime. After these preliminary observations, it is time that we should take a closer view of the general statistics of the movement of crime in Europe, so far as they may be followed in official figures.