In Chicago Board of Trade _v._ Olsen,[435] involving the Grain Futures Act, the same course of reasoning was repeated. Speaking of the Swift Case, Chief Justice Taft remarked: "That case was a milestone in the interpretation of the commerce clause of the Constitution. It recognized the great changes and development in the business of this vast country and drew again the dividing line between interstate and intrastate commerce where the Constitution intended it to be. It refused to permit local incidents of a great interstate movement, which taken alone were intrastate, to characterize the movement as such."[436] Of special significance, however, is the part of the opinion which was devoted to showing the relation between future sales and cash sales, and hence the effect of the former upon the interstate grain trade. The test, said the Chief Justice, was furnished by the question of price. "The question of price dominates trade between the States. Sales of an article which affect the country-wide price of the article directly affect the country-wide commerce in it."[437] Thus a practice which demonstrably affects prices would also affect interstate trade "directly," and so, even though local in itself, would fall within the regulatory power of Congress. In the following passage, indeed, Chief Justice Taft whittles down, in both cases, the "direct-indirect" formula to the vanishing point: "Whatever amounts to more or less constant practice, and threatens to obstruct or unduly to burden the freedom of interstate commerce is within the regulatory power of Congress under the commerce clause, and it is primarily for Congress to consider and decide the fact of the danger and meet it. This court will certainly not substitute its judgment for that of Congress in such a matter unless the relation of the subject to interstate commerce and its effect upon it are clearly nonexistent."[438] And it was in reliance on the doctrine of these cases that Congress first set to work to combat the Depression in 1933 and the years immediately following. But in fact, much of its legislation at this time marked a wide advance upon the measures just passed in review. They did not stop with regulating traffic among the States and the instrumentalities thereof; they also essayed to govern production and industrial relations in the field of production. Confronted with this revolutionary claim to power on Congress' part, the Court again deemed itself called upon to define a limit to the commerce power that would save to the States their historical sphere, and especially their customary monopoly of legislative power in relation to industry and labor management. THE SECURITIES AND EXCHANGE COMMISSION