. . . . "Footnote 19 H. R. Rep. No. 1413, 75th Cong., 1st Sess. 10 (the Conference Report of the House) merely stated: This amendment provides for an amendment to the antitrust laws under which contracts and agreements stipulating minimum resale prices of certain commodities, and which are similar to contracts and agreements which are lawful as applied to intrastate commerce, are not to be regarded as bei" .