making the order was to secure from carriers evidence of infractions of the law in order that suits might be brought to recover penalties; that, even if this were not the purpose, the result of the requirement would be the same, because of the provision that the Commission should lodge with the proper district attorneys information of the violations coming to its knowledge; and that this compulsory disclosure, both as to the corporation itself and as to the officers concerned in such violations, was repugnant to the Fourth and Fifth Amendments of the Constitution of the United States. It was also alleged which a common carrier shall comply with the provisions of this proviso as to such case.

SEC. 3. That any such common carrier, or any officer or agent thereof, requiring or permitting any employé to go, be, or remain on duty in violation of the second section hereof, shall be liable to a penalty of not to exceed five hundred dollars for each and every violation, to be recovered in a suit or suits to be brought by the United States district attorney in the district court of the United States having jurisdiction in the locality where such violation shall have been committed; and it shall be the duty of such district attorney to bring such suits upon satisfactory information being lodged with him; but no such suit shall be brought after the expiration of one year from the date of such violation; and it shall also be the duty of the Interstate Commerce Commission to lodge with the proper district attorneys information of any such violations as may come to its knowledge. In all prosecutions under this Act the common carrier shall be deemed to have had knowledge of all acts of all its officers and agents: Provided, That the provisions of this Act shall not apply in any case of casualty or unavoidable accident or the act of God; nor where the delay was the result of a cause not known to the carrier or its officer or agent in charge of such employé at the time said employé left a terminal, and which could not have been foreseen: Provided further, That the provisions of this Act shall not apply to the crews of wrecking or relief trains.

SEC. 4. It shall be the duty of the Interstate Commerce Commission to execute and enforce the provisions of this Act, and all powers granted to the Interstate Commerce Commission are hereby extended to it in the execution of this Act.

SEC. 5. That this Act shall take effect and be in force one year after its passage.

that the Commission was without authority to make the order, either under the provisions of the act or otherwise. A demurrer for want of equity was sustained, and the complainant appeals.

First. Although the question was not specifically raised by the bill, it is now contended that the statute is unconstitutional in its entirety and therefore no action of the Commission can be based upon it. It is said that it goes beyond the power which Congress may exercise in the regulation of interstate commerce; that while addressed to common carriers engaged in interstate transportation by railroad to any extent whatever, its prohibitions and penalties are not limited to interstate commerce, but apply to intrastate railroads and to employés engaged in local business.

The prohibitions of the act are found in § 2. This provides that it shall be "unlawful for any common carrier, its officers or agents, subject to this Act to require or permit any employé subject to this Act to be or remain on duty" for a longer period than that prescribed. The carriers and employés subject to the act are defined in § 1 as follows:

"That the provisions of this Act shall apply to any common carrier or carriers, their officers, agents, and employés, engaged in the transportation of passengers or property by railroad in the District of Columbia or any Territory of the United States, or from one State or Territory of the United States or the District of Columbia to any other State or Territory of the United States or the District of Columbia, or from any place in the United States to an adjacent foreign country, or from any place in the United States through a foreign country to any other place in the United States. The term 'railroad' as used in this Act shall include all bridges and ferries used or operated in connection with any railroad, and also all the road in use by any common carrier operating a rail

road, whether owned or operated under a contract, agreement, or lease; and the term 'employés' as used in this Act shall be held to mean persons actually engaged in or connected with the movement of any train."

No difficulty arises in the construction of this language. The first sentence states the application to carriers and employés who are "engaged in the transportation of passengers or property by railroad" in the District of Columbia or the Territories, or in interstate or foreign commerce. The definition in the second sentence, of what the terms "railroad" and "employés" shall include, qualify these words as previously used, but do not remove the limitation as to the nature of the transportation in which the employés must be engaged in order to come within the provisions of the statute. If the definition, in the last part of the sentence, of the words used in the first part be read in connection with the latter the meaning of the whole becomes obvious. The section, in effect, thus provides: "This act shall apply to any common carrier or carriers, their officers, agents, and employés (meaning by 'employés' persons actually engaged in or connected with the movement of any train), engaged in the transportation of passengers or property by railroad (meaning by 'railroad' to include all bridges and ferries used or operated in connection with any railroad) in the District of Columbia or any Territory or from one

State to any other State," etc. In short, the employés to which the act refers, embracing the persons described in the last sentence of the section, are those engaged in the transportation of passengers or property by railroad in the district, territorial, interstate or foreign commerce defined; and the railroad, including bridges and ferries, is the railroad by means of which the defined commerce is conducted.

The statute, therefore, in its scope, is materially different from the act of June 11, 1906, chapter 3073, 34

Stat. 232, which was before this court in the Employers' Liability Cases, 207 U. S. 463. There, while the carriers described were those engaged in the commerce subject to the regulating power of Congress, it appeared that if a carrier was so engaged the act governed its relation to every employé, although the employment of the latter might have nothing whatever to do with interstate commerce. In the present statute, the limiting words govern the employés as well as the carriers.

But the argument, undoubtedly, involves the consideration that the interstate and intrastate operations of interstate carriers are so interwoven that it is utterly impracticable for them to divide their employés in such manner that the duties of those who are engaged in connection with interstate commerce shall be confined to that commerce exclusively. And thus, many employés who have to do with the movement of trains in interstate transportation are, by virtue of practical necessity, also employed in intrastrate transportation.

This consideration, however, lends no support to the contention that the statute is invalid. For there cannot be denied to Congress the effective exercise of its constitutional authority. By virtue of its power to regulate interstate and foreign commerce, Congress may enact laws for the safeguarding of the persons and property that are transported in that commerce and of those who are employed in transporting them. Johnson v. Southern Pacific Company, 196 U. S. 1; Adair v. United States, 208 U. S. 177, 178; St. Louis, I. M. & S. Railway Company v. Taylor, 210 U. S. 281; Chicago, Burlington & Quincy Railway Company v. United States, decided May 15, 1911, 220 U. S. 559. The fundamental question here is whether a restriction upon the hours of labor of employés who are connected with the movement of trains in interstate transportation is comprehended within this sphere of authorized legislation. This question admits of but one

answer. The length of hours of service has direct relation to the efficiency of the human agencies upon which protection to life and property necessarily depends. This has been repeatedly emphasized in official reports of the Interstate Commerce Commission, and is a matter so plain as to require no elaboration. In its power suitably to provide for the safety of employés and travelers, Congress was not limited to the enactment of laws relating to mechanical appliances, but it was also competent to consider, and to endeavor to reduce, the dangers incident to the strain of excessive hours of duty on the part of engineers, conductors, train dispatchers, telegraphers, and other persons embraced within the class defined by the act. And in imposing restrictions having reasonable relation to this end there is no interference with liberty of contract as guaranteed by the Constitution. Chicago, Burlington & Quincy Railroad Company v. McGuire, 219 U. S. 549.

If then it be assumed, as it must be, that in the furtherance of its purpose Congress can limit the hours of labor of employés engaged in interstate transportation, it follows that this power cannot be defeated either by prolonging the period of service through other requirements of the carriers or by the commingling of duties relating to interstate and intrastate operations.

Second. It is also urged that the statute is void for uncertainty. This objection is based on the wording of the first proviso in § 2 of the act, which is as follows:

"Provided, That no operator, train dispatcher, shall be required or permitted to be or remain on duty for a longer period than nine hours in any twenty-four hour period in all towers, offices, places, and stations continuously operated night and day, nor for a longer period than thirteen hours in all towers, offices, places, and stations operated only during the day time, except in case of emergency, when the employés named in this