226 HARVARD LAW REVIEW, follow that any regulations of commerce made by Congress would not apply to such articles. The true reason is, that the regulations are made in exercise of the police power, and do not conflict with any congressional legislation. In Leisy v. Hardin the court say, as to articles of inter-state commerce, that "if directly dangerous in themselves the State may take appropriate measures to guard against injury before it obtains complete jurisdiction over them. " ^ Whether the court intended to include in this class, articles other than those " unfit for human use, " is not clear, but other judges have not confined the police power of the State to such articles. Poisons and explosives are articles the use of which needs to be carefully regulated. " Arsenic, dynamite powder, and nitro- glycerine are imported into every Stat-e under such restrictions as to their transportation and sale as to render it safe to deal in them. "^ The right of a State to regulate the transportation of nitro-glycerine has been expressly recognized by Congress.^ So, also, it has been held that a State may require all locomotive engi- neers in the State, although engaged in inter-state commerce, to be examined, and may prevent them from operating a locomotive unless duly licensed by the examining board.* "It is conceded that the power of Congress to regulate inter-state commerce is plenary ; that, as incident to it, Congress may legislate as to the qualifications, duties, and liabilities of employes and others on railway trains engaged in that commerce ; and that such legislation will supersede any State action on the subject. But until such legislation is had, it is clearly within the competency of the States to provide against accidents on trains whilst within their limits. Indeed, it is a principle fully recognized by decisions of State and Federal courts that wherever there is any business in which, either from the products created or in the instrumentalities used, there is danger to life and property, it is not only within the power of the States, but it is among their plain duties, to make provision against accidents likely to follow in such business, so that the dangers at- tending it may be guarded against so far as is practicable. " ^ 1 135 U. S. loo, 125. ^ Bowman v. Chicago & N. W. Railway Co., 125 U. S. 465. 504, per Field, J. ^ Rev. Stats., § 4280.
- Smith V. Alabama, 124 U. S. 465; Nashville, etc. Railway Co. v. Alabama, 128 U. S
^ Nashville, etc. Railway Co. v. Alabama, 128 U. S. 96, 99.
