Interstate commerce Law and legislation 219 Transportation 156 Railroads 107 Taxation 81 International trade 80 Freight and freightage 71 Governmental investigations 70 Committees 46 Constitutional law 41 States 36 Rates 31 Refuse and refuse disposal 27 Government publications 26 Ships 25 Law 24 Trucking 23 Carriers 22 Crime 21 Gambling 20 Licenses 20 Securities 20 Canals 17 Corporations 17 Petroleum industry and trade 17 Antitrust law 16 Automobile industry and trade 15 Contempt of legislative bodies 15 Convict labor 15 Courts 15