delivered the opinion of the'court.

Five assignments-of error appear in this record; but they', raise only a single question. It' is, whether the statute of-Missouri,, upon which'the action in the State court-was' founded, is in • conflict with the clausa of the Constitution of the United States that ordains; “ Congress shall' have power to regulate commerce-with foreign'nations, and aihong the several States, and.with the Indian tribes.” The statute, approved Jan. 23, 1872, by its first section, enacted-as follows: “No Texas, Mexican, or-Indian.cattle.shall/be -driven or otherwise-conveyed ip to, or reihain, -in any codnty in this State,- between the first day of Mareh and the first day of November' in each, year, by .any person' or persons' whatsoever.’? .A later section, is in these words: “If any person or persons shall bring into *469 this State any Texas, Mexican, or Indian cattle, in violation of the first section of. this act, he or they shall be liable, in all cases, for all damages sustained on account of disease communicated by said cattle.” Other sections make such bringing' of cattle into the State a criminal- offence, and provide penalties for it. It was, however, upon the provisions we have quoted that this action was brought against the railroad company that had conveyed the cattle into the county. It is noticeable that the statute interposes a direct prohibition against the introduction into the State of all Texas, Mexican, or'Indian cattle during eight months- of each year, without any distinction between such as may be diseased and such as are not. It is true a proviso to the first section enacts that “ when such cattle shall come across the line of the State, loaded upon a railroad car or steamboat, and shall pass through the State without being unloaded, such shall riot be construed as prohibited by the act; but the railroad company or owners.of a "steamboat performing such transportation shall be responsible for all damages which may result from the disease called the Spanish or Texas fever, should thé same occur along the line of transportation; and the existence of such disease along the line of such route shall be prima facie evidence that such disease has been communi'c'ated by such transportation.” This proviso imposes burdens and liabilities for transportation through the State, though the cattle be not unloaded, while the body of the section absolutely prohibits the introduction of any such cattle into the State, with the single exception mentioned.

' It seems hardly necessary to- argue at length, that, unless the statute can be justified as a legitimate, exercise of the police power of the State, it 'is a usurpation of the power vested ex* clusively in Congress. It is a plain regulation ’ of inter-state commerce, a regulation extending to prohibition. Whatever may be the power of a State over, commerce that is completely internal, it can no more prohibit or regulate that which is inter-state than it can that whicji is with foreign nations. Power over one is given by the Constitution of the United States to Congress in the same words in which it is given over -the other, and in both cases it is necessarily exclusive. That the transportation of property from one State to another is a *470 branch of inter-state commerce is undeniable, and no attempt has been made in this case to deny it.

The Missouri statute is a plain interference with such transportation’, an attempted exercise over it of the highest possible power, — that of destruction. It meets at the borders of the State a large and .common subject of commerce, and prohibits its crossing the State line during two-thirds uf each year, with a proviso,', however, that such cattle may come across the line loaded upon a railroad car or steamboat, and pass through the State without being unloaded. But even the right of steamboat owners and railroad companies to transport such property through the State is loaded by the law with onerous liabilities, because of their agency in the transportation. The object and effect' of-, the statute are, therefore, to- obstruct inter-state commerce, and to discriminate between the property of citizens of oüe State and that of citizens of other States.- This court has heretofore said that inter-state transportation of passengers is beyond'the reach of a State legislature.. And if, as we have held, State taxation of persons passing from one State to another, or a State tax upon inter-state transportation of passengers, is prohibited by the Constitution because a burden upon it,- a fortiori, if "possible, is a State tax upon the carriage of. merchandise from State to. State. Transportation is' essential to commerce, or rather it is commefee itself; and every obstacle .to it, or burden laid upon.it by legislative authority, is regulation. Ca se of the State Freight Tax, 15 Wall. 232; Ward v. Maryland, 12 id. 418; Welton v. The State of Missouri, 91 U. S. 275; Henderson et al. v. Mayor of the City of New York et al., 92 id. 259; Chy Lung v. Freeman et al., id. 275. The two latter of-these cases refer to obstructions against the admission of persons into a State, but the principles asserted are equally applicable to all subjects of commerce.

We are thus brought to the question whether, the Missouri statute is a lawful exercise of the police power of the State. We admit that the-deposit in Congress of the powér to regulate foreign commerce and commerce among the States was not a surrender .of. that which may properly be denominated police power. What that power is, it is difficult to define with sharp precision. It is generally said to extend to making regulations *471 promotive of domestic order, morals, Health, and safely. As was said in Thorp v. The Rutland & Burlington Railroad Co., 27 Vt. 149, “it extends to the protection of. the lives, limbs-,' health, comfort, and quiet of all persons, and -the protec-. tion of all property within the State. According .to the maxim, sic utere tuo ut alienum non Icedas, which, being of universal application, it must, of course, be within the range of. legislative action to define the mode and manner in which every one may so use his own as not to injuré- others.”- It was further said,that, by the general- police .power of a State, “ persons and property are subjected to all kinds of. restraints and burdens, in order to secure' the general comfort, health, and prosperity of the State; of the perfect right of the-legislature'to do which no question ever was, or upon acknowledged' general principles ever can be made, so far as natural persons are concerned.” It may also be admitted that the police powers of a State justifies the adoption of precautionary measures'against socialevils. Under it a State may legislate to prevent the spread of crime, or pauperism, or disturbance of the 'peace; It may exclude from its limits convicts, paupers, idiots, and lunatics, and persons likely to become a public- charge, as well as persons' afflicted by contagious or infectious diseases ; a right founded,, as intimated in The Passenger Cases, 7 How. 283, by Mr. Justice Greer, in the sacred law of self-defence. Vide 3 Sawyer, 283. The same principle, it may also be conceded, would justify the exclusion of property dangerous to the property of citizens of the State'; for example, animals having contagious or infectious diseases. All these exertions'of power are in immediate connection with the protection of persons and property against noxious acts of other persons, or such a use of property as is injurious to the property of others. They are self-defensive.

But whatever may be the nature and reach of the police .power of a State, it cannot be exercised over a subject confided exclusively to Congress by the Federal Constitution. It cannot invade the domain of the national government. It was said in Henderson et al. v. Mayor of the City of New York et al., supra, to “ be clear, from the nature of our. complex form of. government, that whenever the statute of a State invades the domain of legislation which belongs exclusively to the Congress of the *472 United States, it is void, no matter under wheril-ten of powers it may-fail, or bow closely allied it may be to pov.n-temabeeded to belong to the States.” Substantially the sametril of was said'by Chief Justice Marshall in Gibbons v. Ogden, 9 W pract Neither'the unlimited powers óf a State .to-tax, nor any of- ax large police powers, can .be.exercised to such an extent' ae to-work-a-ptactical assumption of the powers properly conferred upon Congress by the Constitution. - Many acts; of. a State may, indeed,, affect commerce, without amounting to a regulation, of-it, in the constitutional sense of the term. And it -is sometimes difficult to define the distinction between that which merely affects or- influences and that- which regulates- or furpishes a rule for conduct, . There is no such difficulty in, .the present case. While we unhesitatingly admit' that a State may pass sanitary Jaws, and laws for the protection of life, liberty, health* -or ' property within its bqrders;' while it may prevent persons and animals suffering -under cop<tagious or infectious diseases, or conticts, &c., from- entering the State; while for the purpose of self-protection it may establish quarantine, and reasonable inspection laws, it.may not interfere with transportation into-or through the State, beyond' what is absolutely necessary for its self-protectioff. It may not, under the cover of exerting its police powers, substantially’ prohibit or burden either foreign or .inter-state commerce. Upon this subject the cases in 92 U. S. to which we have referred are very instructive. In Henderson v. The Mayor, &c., the statute of New York was defended as a police regulation to protect the State against the influx of foreign paupers; 'but it was held to be unconstitutional, because its practical result, was to impose a burden upon all passengers from foreign "countries. And it was laid down that, “ in whatever, language a statute may be framed, its purpose must be determined by Its-natural and. reasonable effect.” The reach of the statute was far beyond its professed object, and far into the realm which is • within • the ’exclusive jurisdiction of Congress. So in the -case of Chy Lung v. Freeman, where the pretence was the exclusion of lewd women; but as the statute was more far-reaching, and affected other immigrants, not of any class which the State could lawfully exclude, we held it unconstitutional. *473 Neither of these eases denied the right of a State, to protect herself against paupers, convicted criminals, or lewd women, by necessary and proper laws, in the - absence of legislation by Congress, but it was ruled that the right could only arise from vital necessity, and that it could not be carried beyond the scope of that necessity. These cases, it is true, speak only of laws affecting the entrance of persons into a State ; but the constitutional doctrines they maintain are equally applicable to inter-state transportation of property. They deny validity to any State legislation professing to be an exercise of police power for protection against evils from • abroad, which is beyond the necessity for its exercise'wherever, it interferes with the rights and powers of the Federal government.

Tried by this rule, the statute of Missouri is a plain intrusion upon the exclusive domain of Congress. It is not a quarantine law. It is .not an inspection law. It says t'o all natural persons and to all .transportation companies, “You shall not bring into the 'State any Texas cattle or any Mexican cattle or Indian cattle, between March 1 and Dec. 1 in any year, no matter whether they are free from disease or not, no matter whether they niay do an injury to the inhabitants of the State or not; and if you do bring them in, even for-the purpose of carrying them' through the State without ‘unloading them, you shall be .subject-to extraordinary liabilities.”. Such.a statute, we do not doubt, it is beyond the power of a State to enact. To hold otherwise would be to ignore one of the leading objects which the Constitution of the United States was designed to secure..

In coming to such a conclusion, we have not overlooked the. 'decisions of very respectable courts in Illinois, where statutes' similar to the one we have- before us have been sustained. Yeazel v. Alexander, 58 Ill. 254. Regarding the statutes as mere police regulations, intended to protect domestic cattle against infectious disease, those courts have refused to inquire whether the prohibition did not extend beyond the danger to be apprehended, and whether, therefore, the statutes were npt something- more than exertions of police power. That inquiry, they have said, was. for the legislature and not for the courts. With this we cannot concur. The-police power of a State cannot obstruct foreign commerce or intér-state commerce *474 beyond tbe necessity for its exercise; and under color of it objects not within its scope cannot be secured at the expense of the protection afforded by the Federal Constitution. And as its range sometimes comes very near to the field committed by the. Constitution to Congress, it is the duty of the courts to guard vigilantly against any needless intrusion.

Judgment reversed, and the record remanded with instructions to reverse the judgment of the Circuit Court of Grundy County, and to direct that court to award a new trial.