All of the thirteen States were in possession of this power, and had exercised it at the adoption of the Constitution; and it is not pretended that any grant of it to the general government is found in that instrument. It is therefore one of the sovereign powers vested in the States by their constitutions, which remained unaltered and unimpaired, and in respect to which the State is as independent of the general government as that government is independent of the States. In respect to reserved powers, the State is as sovereign and as independent as the general government.[114] The means and instrumentalities employed by the one government to carry its powers into operation are as necessary to its self-preservation as the means and instrumentalities are necessary to the other. Unimpaired existence is as essential to the one as to the other. There is no express provision in the Constitution that prohibits the general government from taxing the means and instrumentalities of the States, or prohibiting such taxation. In both cases the exemption rests upon necessary implication, and is upheld by the great law of self-preservation; as any government whose means employed in conducting its operations, if subject to the control of another and distinct government, can exist only at the mercy of that government.[115] 45. This was the constitutional law of the United States as settled in 1870,[116] the case arising in Massachusetts; the plaintiff a judicial officer of that Commonwealth having brought suit to recover from the United States Revenue Collector the amount of income tax exacted from him, it being part of his salary as a judge in that Commonwealth. The Supreme Court of the United States sustained the plaintiff for reasons given in the opinion, part of which has been quoted. By parity of reasoning, as followed in that decision, any act of Congress imposing a tax on the salary of any State officer, if his office is a means and instrumentality employed by the State to carry its powers into operation must be declared unconstitutional. In 1913 the Constitution was amended so that “The Congress shall have power to lay and collect taxes on incomes from whatever source derived, without apportionment among the several States, and without regard to any census or enumeration.”[117]