It is further noteworthy that since the Granger cases themselves, there has been no extension of the doctrine of Chief Justice Waite to other trades or industries, while the extent of the doctrine, that is, the amount of regulation permissible under the Constitution, has been very much limited. Waite's opinion gives no intimation of any constitutional limit whatever, but dozens of the decisions of the Supreme Court since draw the limit this side of the point of confiscation; that is to say, at a "reasonable return," whatever that phrase may mean. It was, indeed, at first extended to semi-private grain elevators on the prairies, to elevators monopolizing the water front of Buffalo, New York, and to floating elevators in New York Harbor, the first and last of which show certainly no element of legal monopoly, while the Buffalo case at most only a geographical one. Still, elevators were the subject of Munn _v_. Illinois itself.[1] And it has never been extended to a mere _de facto_ or "virtual" monopoly arising only from the accident of trade. Moreover, in matters of interstate commerce, although it might have been argued that such affairs were left absolutely to the plenary power of Congress, which might well, if it chose, pass laws preventing any railroad from engaging in interstate business, except at a certain rate per mile for passengers or freight--or that no vessel should be allowed to carry passengers or freight from foreign countries except at a certain price per head or per ton--yet the Supreme Court seems to have held that even this plenary power over commerce expressly given to Congress in the Constitution, is limited by the ordinary property guarantees of that instrument; possibly because the Fifth Amendment is of later date than the body of the Constitution. [Footnote 1: We may divide monopolies into legal, geographical, and _de facto_, or "virtual" monopolies--phrases which sufficiently describe themselves.]