1887, the Metropolitan police arrested 4,556 persons under the provisions of the Vagrant and Poor Law Acts; but in the year 1888, the number arrested by the same body under the same acts amounted to 7,052.  It is perfectly obvious that this vast increase of apprehensions was not owing to a corresponding increase in the number of rogues, beggars, and vagrants; it was principally owing to the increased stringency with which the Metropolitan police carried out the provisions of the Vagrant and Poor Law Acts.  An absolute proof of the correctness of this statement is the fact that throughout the whole of England there was a decrease in the number of persons proceeded against in accordance with these acts.  These examples will suffice to show what an immense power the police have in regulating the volume of certain classes of offences.  In some countries they are called upon to exercise this power in the direction of stringency; in other countries it is exercised in the direction of leniency; and in the same country its exercise, as we have just seen, varies according to the views of whoever, for the time being, happens to have a voice in controlling the action of the police.  In these circumstances it is obviously impossible to draw any accurate comparison between the lighter kinds of offences in one country and the same class of offences in another.

In the case of the more serious offences against person and property, the initiative of putting the law in motion rests chiefly with the injured individual.  The action of the individual in this respect depends to a large extent on the customs of the country.  In some countries the injured person, instead of putting the law in motion against an offender, takes the matter in his own hands, and administers the wild justice of revenge.  Great differences of opinion also exist among different nations as to the gravity of certain offences.  Among some peoples there is a far greater reluctance than there is among others to appeal to the law.  Murder is perhaps the only crime on which there exists a fair consensus of opinion among civilised communities; and even with regard to this offence it is impossible to overcome all the judicial and statistical difficulties which stand in the way of an international comparison.

In spite, however, of the fact that the amount of crime committed in civilised countries cannot be subjected to exact comparison, there are various points on which the international statistics of crime are able to render valuable service.  It is important, for instance, to see in what relation crime in different communities stands to age, sex, climate, temperature, race, education, religion, occupation, home and social surroundings.  If we find, for example, an abnormal development of crime taking place in a given country at a certain period of life, or in certain social circumstances, and if we do not discover the same abnormal development taking place in other countries at a similar period of life, or in a similar social