QUARANTINE LAWS. 299
the inaction of Congress. It is thus stated by Mr. Justice Bradley, in the opinion of the court in Robbins v, Shelby Taxing District :^ " Another established doctrine of this court is, that where the power of Congress to regulate is exclusive, the failure of Congress to make express regulations indicates its will that the subject shall be left free from restrictions or impositions ; and any regulation of the subject by the States, except in matters? of local concern only, as hereafter mentioned, is repugnant to such freedom.*' An ample number of cases are cited in the opinion in support of this proposition.^ The exception stated by Judge Bradley would seem to indicate that the rule was not absolutely rigid, but simply one of construction. This exception was made the ground of the decision in County of Mobile v. Kimball,^ holding constitutional State legislation for the improvement of Mobile harbor. The court say : " Inaction of Congress upon these subjects of a local nature or operation, unlike its inaction upon matters affecting all the States and requiring uniformity of regulation, is not to be taken as a declaration that nothing shall be done with respect to them, but is rather to be deemed a declaration that for the time being, and until it sees fit to act, they may be regulated by State authority."* In the recent Iowa liquor-law case. Bowman v, Chi- cago & N. W. Ry. Co.,^ the court say : " The question, therefore, may be still considered in each case as it arises, whether the fact that Congress has failed in the particular instance to provide by law a regulation of commerce among the States is conclusive of its intention that the subject shall be free from all positive regulation, or that until it positively interferes, such com- merce may be left to be freely dealt with by the respective States." The question whether the inaction of Congress was to be taken as equivalent to a declaration that the interstate transportation of intoxicating liquors should be subject to no restraints, and there-
1 120 u. S. 489, 493 (1886).
^ To the cases there collected the following may be added to complete the sequence of cases: Hinson v, Lott., 8 Wall. 148, 152 (1868); Welton v. State of Missouri, 91 U. S. 275, 282 (1875), perhaps the first case where the court lay down the rule; Trans- portation G). V. Parkersburg, 107 U. S. 691, 702 (1882); Philadelphia Steamship Co.t^. Pennsylvania, 122 U. S. 326, 336; Bowman v. Chicago & N. W. Ry. Co., 125 U. S. 465^ 8 Sup. Ct. Rep. 689 (1888).
• 102 U. S. 691, 699 (1880).
«To the same effect is TransporUtion Co. v. Parkersburg, X07 U. S. 691 (1882).
» 125 U. S. 483, 8 Sup. Ct. Rep. 689, 697.
