In 1906 Congress passed an act entitled "An Act Relating to Liability of Common Carriers in the District of Columbia and Territories and Common Carriers Engaged in Commerce between the States and between the States and Foreign Nations to their Employees," 10 by which act the fellow-servant doctrine of the common law was considerably modified. By the terms of this act "every common carrier in trade or commerce" in the District of Columbia or in the Territories or between the several States was made liable for the death or injury of "any of its employees" which should result from the negligence of "any of its officers, its,'or employees." It thus appears that the provisions of the acts were made applicable to these companies irrespective of the fact whether the person injured or killed was engaged at the time in interstate commerce. The only criterion prescribed was that the employing company was one carrying on commerce among the States. There was thus raised the fundamental question whether the simple fact that a company or corporation is, in any part of its business, engaged in carrying on interstate commerce renders it subject to federal regulation as to all its activities. There was also raised the question whether the relation between an employing company and its employees is itself a part of the interstate commerce which the company carries on. Both of these questions were discussed in Howard v. Illinois Central R. Co.11 The first and more important question the court answered in the negative. "To state the proposition," the court say," is to refute it. It assumes that, because one engages in interstate commerce, he thereby endows Congress with power not delegated to it by the Constitution; in other words, with the right to legislate concerning matters of purely state concern. It rests upon the conception that the Constitution destroyed that freedom of commerce which it was its purpose to preserve, since it treats the right to engage in interstate commerce as a privilege which cannot be availed of except upon such conditions as Congress may prescribe, even although the conditions would be otherwise beyond the power of Congress. It is apparent that if the contention were well founded it would extend the power of Congress to every conceivable subject, however inherently local, would obliterate all the limitations of power imposed by the Constitution, and would destroy the authority of the States as to all conceivable matters
9 96 U. S. 727; 24 L. ed. 877. 10 34 Stat, at L. 232.
11 207 U. S. 463; 28 Sup. Ct. Rep. 141; 52 L. ed. 297. As to the second question the court said: "We fail to perceive any just reason for holding that Congress is without power to regulate the relation of master and servant. to the extent that regulations adopted by Congress on that subject are solely confined to interstate commerce, and therefore are within the grant to regulate that commerce, or within the authority given to use all means appropriate to the exercise of the powers conferred. To illustrate: Take the case of an interstate railway train; that is, a train moving in interstate commerce, and the regulation of which therefore is, in the nature of things, a regulation of such commerce. It cannot be said that because a regulation adopted by Congress as to such train when so engaged in interstate commerce deals with the relation of the master to the servants operating such train or the relations of the servants engaged in such operation between themselves, that it is not a regulation of interstate commerce. This must be, since to admit the authority to regulate such train, and yet to say that all regulations which deal with the relation of master and servants engaged in its operation are invalid for want of power, would be but to concede that power and then to deny it; or, at all events, to recognize and yet render it incomplete." which, from the beginning, have been, and must continue to be, under their control so long as the Constitution endures."
The court then go on to hold the act void as to the States because its application was not limited by its terms to injuries and deaths incurred by persons while engaged at the time in interstate commerce.12