How complete is the circle of points in which the state touches the life of the American citizen, we may see in the fact that our state courts make a complete judiciary system, from top to bottom independent of the federal courts.[15] An appeal may be carried from a state court to a federal court in cases which are found to involve points of federal law, or in suits arising between citizens of different states, or where foreign ambassadors are concerned. Except for such cases the state courts make up a complete judiciary world of their own, quite outside the sphere of the United States courts. [Footnote 15: Independence of the state courts.] [Sidenote: Constitution of the state courts.] We have already had something to say about courts in connection with those primitive areas for the administration of justice, the hundred and the county. In our states there are generally four grades of courts. There are, first, the _justices of the peace _, with jurisdiction over "petty police offences and civil suits for trifling sums." They also conduct preliminary hearings in cases where persons are accused of serious crimes, and when the evidence seems to warrant it they may commit the accused person for trial before a higher court. The mayor's court in a city usually has jurisdiction similar to that of justices of the peace. Secondly, there are _county_ and _municipal courts_, which hear appeals from justices of the peace and from mayor's courts, and have original jurisdiction over a more important grade of civil and criminal cases. Thirdly, there are _superior courts_, having original jurisdiction over the most important cases and over wider of the state areas of country, so that they do not confine their sessions to one place, but move about from place to place, like the English _justices in eyre_. Cases are carried up, on appeal, from the lower to the superior court. Fourthly, there is in every state a _supreme court_, which generally has no original jurisdiction, but only hears appeals from the decisions of the other courts. In New York there is a "supremest" court, styled the _court of appeals_, which has the power of revising sundry judgments of the supreme court; and there is something similar in New Jersey, Illinois, Kentucky, and Louisiana.[16] [Footnote 16: Wilson. The State, pp. 509-513.]