“It is necessary in the first instance that the parties in the market should be free to sell and buy at any price at which they can find a partner to the transaction and that anybody should be free to produce, sell, and buy anything that may be produced or sold at all. And it is essential that the entry into the different trades should be open to all on equal terms and that the law should not tolerate any attempts by individuals or groups to restrict this entry by open or concealed force.”
