In Anderson v. United States,40 decided the same day as the Hopkins ease, an association of dealers in live stock, providing by its rules that its members should not transact business with non-members, nor with commission men who should deal with non-members, was held not a combination or conspiracy in restraint of interstate trade, inasmuch as it appeared that membership was open to all dealers, and no attempt was made to control prices or the number of cattle bought nor in any way to prevent full competition between the members. In this case the ground taken by the court was not so much that the combination did not relate to interstate commerce, as that there was no restraint upon commerce imposed by its rules, nor an attempt to monopolize such commerce.