is partly exclusive and partly concurrent. If one invades a province which belongs exclusively to the other, it acts without right (if not without power), and ought to be restrained by the common sovereign. If a particular province belongs to them both (i.e., if they have concurrent jurisdiction over it), each is entitled to enter it, while neither is entitled to interfere with the other; and hence questions of priority are liable to arise between them, i. e., questions as to which of them first obtained jurisdiction over given controversies. But the terms “concurrent” and “exclusive” have no proper application to equity, or rather they do not correctly describe the relations between equity and the other three systems. On the one hand, equity never excludes either of the other systems. It is true that equity alone exercises jurisdiction over equitable rights; but that is not because equity claims any monopoly of such jurisdiction,—it is because the other systems decline to exercise it, they not recognizing equitable rights. On the other hand, equity is never excluded by either of the other systems; and hence equity exercises jurisdiction over legal rights (as well as over equitable rights) without any external restraint. Since, however, one or more of the other systems has jurisdiction over every legal right, the jurisdiction of equity over legal rights is in a certain sense concurrent, but never in any proper sense; and not unfrequently it is in fact exclusive in the sense of being the only jurisdiction that is actually exercised. It is not properly concurrent, because there is no competition between the two jurisdictions. Courts of law act just as they would act if equity had no existence, just as in fact they did act before equity had any existence. Nor does equity ever complain of their so acting, or seek to put any restraint upon their action, or question the validity and legality of their acts; and yet equity acts with the same freedom from restraint, even when dealing with legal rights, that courts of law do when dealing with rights of their own creation.
What has thus far been said, however, is calculated rather to stimulate than to satisfy inquiry. How is it that equity has the power to invade at will the provinces of other courts ? What object has equity in assuming jurisdiction over rights which it is the special province of other courts to protect? What is the extent of that jurisdiction? The answer to the first of these questions will be found in the fact that the jurisdiction of equity is a prerogative jurisdiction ; i. e., it is exercised in legal contemplation by