It will be noticed that of these five classes, numbers i. and ii. were common to the whole of England, whilst numbers iii. iv. and v. were peculiar to London and its immediate neighbourhood, but, for our present purpose, it will be more convenient to consider the provincial constabulary as altogether distinct from the various Metropolitan Police bodies. Theoretically and constitutionally, there should have been little or no difference between the policing of London and that of any rural district, but the stage of development reached in the Metropolis already foreshadowed the impending changes, whilst in the country the standard of police had as yet deviated hardly at all from the mediæval pattern. Leaving the London police establishments, therefore, for future consideration, we find that in rural districts, and in provincial towns, High Constables and Parish Constables, acting under the direction of the Justices of the Peace, continued to exercise the time-honoured powers which had been handed down to them from forgotten generations. To get a clear idea of how the old-time system adapted itself, more or less, to the changed conditions that prevailed in the nineteenth century, the best way is to turn to what we may call the police text-books of the period such as the "Treatise on the Functions and Duties of the Constable," by Colquhoun (1803), or "The Churchwardens' and Overseers' Guide," by Ashdowne, published at about the same time. "The High Constable," says Colquhoun, "has the superintendence and direction of the petty constables, headboroughs, and other peace officers in his hundred or division. It is his duty to take cognisance of, and to present, all offences within his hundred or division which lead to the corruption of morals, breaches of the Lord's Day, Drunkenness, Cursing and Swearing. To bring forward sufficient number of constables to maintain decency and good order during the execution of malefactors or the punishment of offenders, and to attend in person to see that the peace officers do their duty. To summon petty constables to keep order in the Courts of Justice &c...." With regard to tumults and riots, "to do all in his power to arrest offenders, and so to dispose of his constables as to suppress the disorders in question, also to give assistance to neighbouring divisions ... to present all persons exposing for sale unwholesome meat ... and to take cognisance of false or deficient weights and measures." In another place he declares that petty constables should regularly perambulate their districts once at least in every twenty-four hours, and visit all alehouses once a week "to see that no unlawful games are permitted, and that labouring people are not suffered to lounge and tipple until they are intoxicated." The duty of petty constables when riots are threatened is thus described. "The instant a constable hears of any unlawful assembly, mob, or concourse of people likely to produce danger