For even though the line accurately divides the subject matter of the complementary spheres, still national power is always entitled to take on such additional extension as is requisite to guarantee its effective exercise, and is furthermore supreme. THE DANBURY HATTERS CASE In this respect, the Swift Case only states what the Shreveport Case was later to declare more explicitly; and the same may be said of an ensuing series of cases in which combinations of employees engaged in such intrastate activities as manufacturing, mining, building construction, and the distribution of poultry were subjected to the penalties of the Sherman Act because of the effect or intended effect of their activities on interstate commerce.[429] STOCKYARDS AND GRAIN FUTURES ACTS In 1921 Congress passed the Packers and Stockyards Act[430] whereby the business of commission men and livestock dealers in the chief stockyards of the country was brought under national supervision; and the year following it passed the Grain Futures Act[431] whereby exchanges dealing in grain futures were subjected to control. The decisions of the Court sustaining these measures both built directly upon the Swift Case. In Stafford _v._ Wallace,[432] which involved the former act, Chief Justice Taft, speaking for the Court, said: "The object to be secured by the act is the free and unburdened flow of livestock from the ranges and farms of the West and Southwest through the great stockyards and slaughtering centers on the borders of that region, and thence in the form of meat products to the consuming cities of the country in the Middle West and East, or, still as livestock, to the feeding places and fattening farms in the Middle West or East for further preparation for the market."[433] The stockyards, therefore, were "not a place of rest or final destination." They were "but a throat through which the current flows," and the sales there were not merely local transactions. "They do not stop the flow;--but, on the contrary" are "indispensable to its continuity."[434]