In 1935, it was held[998] that an order of the New York Commissioner of Agriculture prohibiting the importation of cattle for dairy or breeding purposes unless such cattle and the herds from which they come had been certified by the chief sanitary officer of the State of origin as being free from Bang's disease, was not in conflict with the Cattle Contagious Diseases Acts.[999] In 1937, it was ruled[1000] that a Georgia statute fixing maximum charges for handling and selling leaf tobacco did not, as applied to sales of tobacco destined for export, conflict with the Tobacco Inspection Act.[1001] In 1942,[1002] it was held that an order of the Wisconsin Employment Relations Board which commanded a union, its agents, and members, to desist from mass picketing of a factory, threatening personal injury or property damage to employees desiring to work, obstructing the streets about the factory, and picketing the homes of employees, was not in conflict with the National Labor Relations Act,[1003] to which the employer was admittedly subject but which had not been invoked. An "intention of Congress," said the Court, "to exclude States from exerting their police power must be clearly manifested."[1004] In 1943,[1005] the Court sustained the marketing program for the 1940 California raisin crop, adopted pursuant to the California Agricultural Prorate Act. Although it was conceded that the program and act operated to eliminate competition among producers concerning terms of sale and price as to product destined for the interstate market, they were held not to conflict with the commerce clause or with the Sherman Act or the Agricultural Marketing Agreement Act.[1006] To the contrary, said Chief Justice Stone, speaking for the unanimous court, the program "is one which it has been the policy of Congress to aid and encourage through federal agencies" under federal act.[1007] The case was not one, he further observed, which was to be resolved by "mechanical test," but with the object in view of accommodating "the competing demands of the State and national interests involved."[1008] In 1944,[1009] the Court upheld the right of Minnesota to exclude from its courts a firm licensed by the National Government to carry on the business of customs broker because of its failure to comply with a State statute requiring foreign corporations to obtain a license to do business in the State. Speaking for the Court, Justice Frankfurter, again disparaged "the generalities" to which certain cases had given utterance. Actually, he asserted, "the fate of State legislation in these cases has not been determined by these generalities but by the weight of the circumstances and the practical and experienced judgment in applying these generalities to the particular instances."[1010] In cases, decided in 1947,[1011] the Court ruled that Indiana had not violated the Natural Gas Act[1012] by attempting to regulate the rates for natural gas sold within the State by an