159. “The words ‘due process of law’ were undoubtedly intended to convey the same meaning as the words, ‘by the law of the land’ in Magna Charta.” This means, in American constitutional law, to use Webster’s words in the Dartmouth College case,—“the general law—a law which hears before it condemns; which proceeds upon inquiry, and renders judgment only after trial.” Cooley states it as meaning “that every citizen shall hold his life, liberty, property, and immunities, under the protection of the general rules which govern society.”[445] This means that whatever is the actual law of the land, the regular and established practice of courts and the legal landmarks of society defines the meaning of the phrase “due process of law.” A man who by the laws of his State has had a fair trial in a court of justice, according to the modes of proceeding applicable to such a case has been tried by due process of law.[446] It is within the police power of a State to regulate the hours during which a business, say washing and ironing, may be carried on, and the kind of building, whether or not fireproof, which may be used for such business, but discrimination against citizens or aliens effecting the elimination of certain citizens or aliens from carrying on the business, while others are permitted to carry it on under similar conditions is a violation of the Fourteenth Amendment which secures to every person the equal protection of the laws. The discrimination is none the less unconstitutional because the person discriminated against is an alien, when the treaty between the United States and the sovereignty to which the alien owes allegiance secures to the alien in the United States “the same rights, privileges, immunities, and exemptions as may be enjoyed by the citizens or subjects of the most favored nation.” For a treaty is part of the supreme law of the land.[447] The principle here also includes another well-settled rule of American constitutional law, that while a State may exercise its police power within its own jurisdiction, imposing restrictions on foreign corporations doing business within its territory, it cannot so exercise its police power as to infringe upon interstate or foreign commerce. Thus a police regulation of a State which prevents or obstructs, directly or indirectly, a corporation within its territory, as a party that is engaged or would be engaged in commerce, conflicts with the power of Congress to regulate commerce and therefore is unconstitutional. But police regulation of the corporation as to other matters is not a violation of the Fourteenth Amendment.[448] The principle here is “to exclude everything that is arbitrary and capricious in legislation affecting the rights of the citizen.”[449]