the power of the State over the general subject of commerce has been divided into three classes: First, those in which the power of the State is exclusive; second, those in which the States may act in the absence of legislation by Congress; third, those in which the action of Congress is exclusive and the State cannot act at all. Covington &c. Bridge Co. v. Kentucky, 154 U. S. 204, 209; Western Union Telegraph Co. v. James, 162 U. S. 650, 655.

These divisions, however, express but the extreme boundaries of the subject. Something more definite is necessary for the decision of the opposing contentions in the case at bar. The Supreme Court of the State was of the view that the statute simply regulated a duty which preceded the entry of the goods in interstate commerce, and concluded, therefore, that the statute was "neither an interference with nor a burden upon interstate commerce.” And it decided that the execution of this duty was not precluded by the provision of the Interstate Commerce Act requiring a schedule of tariffs to be established and charged. It was said by the court that it was the duty of the railway company to file such schedule, and that the company could not justify the violation of its common law duty by the neglect of its statutory duty.

The case, however, is not quite in such narrow compass. There is something more to be considered than the accumulation of defaults, if there be defaults. It is undoubtedly the duty of a railway company to receive freight when tendered for transportation. It may, besides, have other obligations, but it does not follow that it is within the power of the State to enforce them. There may be a Federal exertion of authority which takes from a State the power to regulate the duties of interstate carriers or to provide remedies for their violation. This is realized by defendants in error, and they assert that the state statute is in aid of commerce, and not an interference with or burden upon it, and therefore must be sustained as a valid exer

cise of the State's power, citing Atlantic Coast Line R. R. Co. v. Mazursky, 216 U. S. 122; Western Union Tel. Co. v. James, 162 U. S. 650.

In those cases, and in the later case of Western Union Tel. Co. v. Milling Co., 218 U. S. 406, the principle is expressed that "there are many occasions where the police power of the State can be properly exercised to insure a faithful and prompt performance of duty within the limits of the State upon the part of those engaged in interstate commerce." Such exercise of power, it was further said, was in aid of interstate commerce, and, although incidentally affecting it, did not burden it. But the facts of those cases distinguish them from the case at bar, and make their principle inapplicable. In the Telegraph Company cases there was a failure to transmit or deliver telegrams, in violation of the duty so to do imposed by the particular state statutes. In the railroad case a statute of the State of South Carolina which required carriers to settle within a specified time claims for loss of or damages to freight while in their possession within the State was sustained against the objection that it was an interference with interstate commerce. In none of the cases, however, was there any Federal legislation upon the subject involved, and in all of them such circumstance was stated as an element of decision. The circumstance is important, and we are brought to the inquiry whether it exists in the present case.

It is well settled that if the State and Congress have a concurrent power, that of the State is superseded when the power of Congress is exercised. The question occurs: To what extent and how directly must it be exercised to have such effect? It was decided in Missouri Pacific Railway Co. v. Larabee Mills, 211 U. S. 612, that the mere creation of the Interstate Commerce Commission and the grant to it of a large measure of control over interstate commerce does not, in the absence of action by it, change the rule

that Congress by nonaction leaves power in the States over merely incidental matters. "In other words," and we quote from the opinion (p. 623), "the mere grant by Congress to the commission of certain national powers in respect to interstate commerce does not of itself and in the absence of action by the commission interfere with the authority of the State to make those regulations conducive to the welfare and convenience of its citizens.

Until specific action by Congress or the commission the control of the State over those incidental matters remains undisturbed." The duty which was enforced in the state court was the duty of a railroad company engaged in interstate commerce to afford equal local switching service to its shippers, notwithstanding the cars concerning which the service was claimed were eventually to be engaged in interstate commerce. This duty was declared (p. 624) to be a common law duty which the State might, "at least in the absence of Congressional action, compel a carrier to discharge."

The principle of that case, therefore, requires us to find specific action either by Congress in the Interstate Commerce Act or by the Commission covering the matters which the statute of North Carolina attempts to regulate. There is no contention that the Commission has acted, so we must look to the act. Does it, as contended by plaintiff in error, take control of the subject-matter and impose affirmative duties upon the carriers which the State cannot even supplement? In other words, has Congress taken possession of the field?

It is not possible to epitomize the act by giving a more particular designation than that it was designed to regulate interstate commerce. Something more was certainly intended by it than the mere ordaining or the supervision of the movement of goods. In a certain general way traffic would be regulated by railroad and shipper, but their powers were not equal. The railroads had the

greater power, and might and did exercise it in unreasonable charges and in discriminations. The potent instrument for this was the difference in the rate charged for transportation or by secret rebates if the charge was not discriminating in the first instance. Hence we said, in Texas & Pacific Ry. v. Abilene Oil Co., 204 U. S. 426, 437: "The act made it the duty of carriers subject to its provisions to charge only just and reasonable rates." To that end, it was further said, schedules of rates were required to be established and published, and departure from the rates established, except in the manner authorized by the act, was forbidden under criminal penalties, and any injury to persons was provided to be redressed through application to the Commission or to the courts. And it is provided that "if no joint rate over a through route has been established, the several carriers in such through route shall file, print and keep open to public inspection, as aforesaid, the separately established rates, fares and charges applied to the through transportation."

The Commission is given the power to determine and prescribe the manner in which the schedules required by the act are to be kept. And it is enacted that, unless otherwise provided, no carrier "shall engage or participate in the transportation of passengers or property, as defined in this act, unless the rates, fares and charges upon which the same are transported by said carrier have been filed and published in accordance with the provisions of this act."

It is evident, therefore, that Congress has taken control of the subject of rate making and charging. All of the particular details we cannot set forth without extensive quotation from the act, which it is quite inconvenient to make. The provisions of the act are directed at the abuses most to be feared, unreasonableness in the rates and discriminations, including in the latter discriminations in service, in the acceptance and delivery of freight and in facilities fur

nished. The power which has been given to the Commission to secure those results we have set forth in Texas &c. Ry. Co. v. Abilene Oil Co. supra, and in Baltimore & Ohio R. R. Co. v. Pitcairn Coal Co., 215 U. S. 481. In the first case it was said (p. 439): "It is apparent that the means by which these great purposes were to be accomplished was the placing upon all carriers the positive duty to establish schedules of reasonable rates which should have a uniform application to all and which should not be departed from so long as the established schedule remained unaltered in the manner provided by law." After citing cases, it was further said (p. 439): "When the general scope of the act is enlightened by the considerations just stated it becomes manifest that there is not only a relation, but an indissoluble unity between the provision for the establishment and maintenance of rates until corrected in accordance with the statute and the prohibitions against preferences and discrimination." In that case it was decided that a shipper could not maintain an action at common law in a state court on the ground that a rate established in accordance with the Interstate Commerce Act was unreasonable. In the second case was considered the power of the Commission under the amendments of 1906, and it was decided that on the principles announced in the Abilene case, and from a consideration of the amendments and their purpose to supply the defects of the act and enlarge the powers of the Commission, the distribution of coal cars by the railroad company among shippers was a matter involving preference and discrimination, and within the competency of the Interstate Commerce Commission to consider, and that the courts could not interfere with such distribution until after action by the Commission. This was resolved notwithstanding § 23 of the act gave jurisdiction to the Circuit and District Courts of the United States to command, at the suit of one aggrieved, a common carrier “to move and trans