on the contract. The extent of this influence depends on the will of a distinct government. To any extent, however inconsiderable, it is a burden on the operations of government. It may be carried to an extent which shall arrest them entirely."
As a sequence to these decisions of the United States Supreme Court, not only has the general principle that no State of the Federal Union can impose any tax upon any agency of the Federal Government—as its mails, its buildings, its lands, its ships, its money, and the like—come to be universally recognized as in the nature of an unquestionable law of the land, but the question of the application of the principle in respect to many cases to which some latitude of opinion was legitimate, has been specially and definitely determined. Thus, for example, it has been established, that a State can not impose license taxes upon persons passing through or coming into it merely for a temporary purpose, especially if connected with interstate commerce; a State, furthermore, can not enact any law or establish any regulation affecting interstate commerce, inasmuch as the same would be an unauthorized interference with the power given to Congress on the subject. Interstate commerce also can not be taxed at all by a State statute, even though the same amount of tax should be laid on commerce which is carried on solely within the State; and the negotiation of sales of goods, which are in another State, for the purpose of introducing them into the State into which said negotiation is made, has been held to be interstate commerce. A tax levied by the State of Michigan of one cent and a half a ton on iron ores, if taken out of the State for smelting, while exempt if smelted within the State, was held by the United States Supreme Court to be a tax on commerce and therefore void.
A State statute which levies a tax upon the gross receipts of railroads for the carriage of freights and passengers into, out of, or through a State has been held to be a tax upon commerce between the States, and therefore void. Under the provision of the Federal Constitution that "no State shall, without the consent of Congress, lay any imposts or duties on imports or exports, except what may be absolutely necessary for executing its inspection laws," some difficulty has been experienced in indicating with sufficient accuracy for practical purposes, the point of time at which articles brought into the country from abroad cease to be regarded as imports in the sense of constitutional protection, and become liable to State taxation. But it has been held by the United States Supreme Court that where the importer has so acted upon the thing imported that it has become incorporated and mixed up with the mass of property in the country, it has lost its distinctive character as an import, and become subject to
