 In the "Shreveport Rate Cases" (1914), the Court permitted congressional regulation of railroad lines because Congress was regulating the "channels of commerce" and although the regulation was on intrastate rail lines, the effect of the intrastate lines was direct so as to concern interstate commerce.In "Schecter Poultry", the Court invalidated a federal statute seeking to enforce labor conditions at a slaughterhouse for chickens; the Court held the relationship between labor conditions and chickens was too indirect - that chickens come to rest upon arrival at the slaughterhouse (thereby ending the stream of commerce), so whatever happened in the slaughterhouse was not Congress's business.In these early cases, the Court approached problems formalistically - from cabining commerce to a specific zone to a direct/indirect test.