1. "All things are double, one against another." (Ecclus. xlii. 25.) The son of Sirach may have had in view the human body as divisible by a vertical median line into two symmetrical halves. But in each of the halves thus made, the same organ or limb is never repeated twice in exact likeness, nor do any two parts render exactly the same service. This variety of organs in the bodies of the higher animals is called _differentiation_. As we descend in the animal series we find less and less of differentiation, till we reach the lowest types, which are little more than a mere bag, whence their name of Ascidians. In that State which has London for its capital city, we behold one of the highest types of political existence. Sovereignty is there divided, as usual in modern States, into three branches, Legislative, Judicial, and Executive. Each of these branches is shared among many persons in various modes and degrees, so that in practice it is not easy to enumerate and specify the holders of sovereignty, nor to characterize so complex a polity. At the other end of the scale we may represent to ourselves 250 "squatters" forming an independent State in the far West of America. They are a pure democracy, and the sovereignty belongs to them all jointly. Is a man to be tried for his life? The remaining 249 are his judges. Is a tax to be levied on ardent spirits? The 250 vote it. Is there a call to arms? The 250 marshal themselves to war. That clearly is the condition of minimum differentiation, where one citizen is in all political points the exact counterpart of all the rest. Of all polities it is the most _simple and elementary_ possible. And so far forth as the natural order of evolution in polities, as in all other things, is from simple to compound, this is also the _original_ polity. It is also the _residuary_ polity, that, namely, which comes to be, when all other government in the State vanishes. Thus, if the Powder Plot had succeeded, and King James I., with the royal family, Lords and Commons, with the judges and chief officers of the Executive, had all perished together, the sovereign authority in England would have devolved upon the nation as a whole.