The question which underlies the immediate question in the case is whether the imposition of the tax upon the steam-ship company's receipts amounted to a regulation of, or an interference with, interstate and foreign commerce, and was thus in conflict with the power granted by the constitution to congress. The tax was levied directly upon the receipts derived by the company from its fares and freights for the transportation of persons and goods between different states, and between the states and foreign countries, and from the charter of its vessels, which was for the same purpose. This transportation was an act of interstate and foreign commerce. It was the carrying on of such commerce. It was that, and nothing else. In view of the decisions of this court, it cannot be pretended that the state could constitutionally regulate or interfere with that commerce itself. But taxing is one of the forms of regulation. It is one of the principal forms. Taxing the transportation, either by its tonnage or its distance, or by the number of trips performed, or in any other way, would certainly be a regulation of the commerce, a restriction upon it, a burden upon it. Clearly, this could not be done by the state without interfering with the power of congress. Foreign commerce has been fully regulated by congress, and any regulations imposed by the states upon that branch of commerce would be a palpable interference. If congress has not made any express regulations with regard to interstate commerce, its inaction as we have often held, is equia lent to a declaration that it shall be free in all cases where its power is exclusive; and its power is necessarily exclusive whenever the subject-matter is national in its character, and properly admits of only one uniform system. See the cases collected in Robbins v. Shelby Taxing-Dist., 120 U. S. 489, 492, 493, ante, 592. Interstate commerce carried on by ships on the sea is surely of this character.

If, then, the commerce carried on by the plaintiff in error in this case could not be constitutionally taxed by the state, could the fares and freights received for transportation in carrying on that commerce be constitutionally taxed? If the state cannot tax the transportation, may it, nevertheless, tax the fares and freights received therefor? Where is the difference? Looking at the substance of things, and not at mere forms, it is very difficult to see any difference. The one thing seems to be tantamount to the other. It would seem to be rather metaphysics than plain logic for the state officials to say to the company: 'We will not tax you for the transportation you perform, but we will tax you for what you get for performing it.' Such a position can hardly be said to be based on a sound method of reasoning.

This court did not so reason in the case of Brown v. Maryland, 12 Wheat. 419. The state of Maryland required all importers of foreign goods and other persons selling the same by wholesale, bale, or package, to take out a license and pay $50 therefor, subject to a penalty and forfeiture for selling without such license. It was contended on the part of the state that this was a mere tax on the occupation of selling foreign goods, affecting only the person, and not the importation of the goods themselves, or the occupation of importing them. Chief Justice MARSHALL met this objection by showing that the attempt to regulate the sale of imported goods was as much in conflict with the power of congress to regulate commerce as a regulation of their importation itself would be. 'If this power,' said he, (referring to the power of congress,) 'reaches the interior of a state, and may be there exercised, it must be capable of authorizing the sale of those articles which it introduces. Commerce is intercourse. One of its most ordinary ingredients is traffic. It is inconceivable that the power to authorize this traffic, where given in the most comprehensive terms, with the intent that its efficacy should be complete, should cease at the point when its continuance is indispensable to its value. To what purpose should the power to allow importation be given, unaccompanied with the power to authorize a sale of the thing imported? Sale is the object of importation, and is an essential ingredient of that intercourse, of which importation constitutes a part. It is as essential an ingredient, as indispensable to the existence of the entire thing, then, as importation itself. It must be considered as a component part of the power to regulate commerce. Congress has a right, not only to authorize importation, but to authorize the importer to sell. * * * Any penalty inflicted on the importer for selling the article in his character of importer must be in opposition to the act of congress which authorizes importation. * * * The distinction between a tax on the thing imported, and on the person of the importer, can have no influence on this part of the subject. It is too obvious for controversy that they interfere equally with the power to regulate commerce.' Pages 446-448.

The application of this reasoning to the case in hand is obvious. Of what use would it be to the ship-owner, in carrying on interstate and foreign commerce, to have the right of transporting persons and goods free from state interference if he had not the equal right to charge for such transportation without such interference? The very object of his engaging in transportation is to receive pay for it. The regulation of the transportation belongs to the power of congress to regulate commerce, the regulation of fares and freights receivable for such transportation must equally belong to that power; and any burdens imposed by the state on such receipts must be in conflict with it. To apply the language of Chief Justice MARSHALL, fares and freights for transportation in carrying on interstate or foreign commerce are as much essential ingredients of that commerce as transportation itself.

It is necessary, however, that we should examine what bearing the Cases of State Freight Tax and Railway Gross Receipts, reported in 15 Wall., have upon the question in hand. These cases were much quoted in argument, and the latter was confidently relied on by the counsel of the commonwealth. They both arose under certain tax laws of Pennsylvania. The first, which is reported under the title of Case of State Freight Tax, 15 Wall. 232, was that of the Reading Railroad Company, any arose under an act passed in 1864, which imposed upon every railroad, steam-boat, canal, and slack-water navigation company a tax of a certain rate per ton on every ton of freight carried by or upon the works of said company, with a proviso directing, in substance, that every company, foreign or domestic, whose line extended party in Pennsylvania, and party in another state, should pay for the freight carried over that portion of its line in Pennsylvania the same as if its whole line were in that state. Under this law, the Reading Railroad Company was charged a tax of $38,000 for freight transported to points within Pennsylvania, and of $46,000 for that exported to points without the state. The latter sum the company refused to pay; and the question in this court was whether that portion of the tax was constitutional, and we held that it was not. Mr. Justice STRONG delivered the opinion of the court. It was held that this was not a tax upon the franchises of the companies, or upon their property, or upon their business, measured by the number of tons of freight carried, but was a tax upon the freight carried, and because of its carriage; that transportation is a constituent of commerce; that the tax was therefore a regulation of commerce, and a regulation of commerce among the state; that the transportation of passengers or merchandise from one state to another is, in its nature, a matter of national importance, admitting of a uniform system or plan of regulation, and therefore, under the rule established by Cooley v. Port-Wardens, 12 How. 299, exclusively subject to the legislation of congress. The inevitable conclusion was that the tax then in question was in conflict with the exclusive power of congress to regulate commerce among the states, and was therefore unconstitutional. Referring to the decision in Crandall v. Nevada, 6 Wall. 35, in which this court had decided that a state cannot tax persons for passing through or out of it, Justice STRONG said: 'If state taxation of persons passing from one state to another, or a state tax upon interstate transportation of passengers, is unconstitutional, a fortiori, if possible, is a state tax upon the carriage of merchandise from state to state in conflict with the federal constitution. Merchandise is the subject of commerce. Transportation is essential to commerce; and every burden laid upon it is pro tanto a restriction. Whatever, therefore, may be the true doctrine respecting the exclusiveness of the power vested in congress to regulate commerce among the states, we regard it as established that no state can impose a tax upon freight transported from state to state, or upon the transporter because of such transportation.' The court in its opinion took notice of the fact that the law was general in its terms, making no distinction between freight transported wholly within the state and that which was destined to or came from another state. But it was held that this made no difference. The law might be valid as to one class, and unconstitutional as to the other. On this subject, Justice STRONG said: 'h e state may tax its internal commerce; but, if an act to tax interstate or foreign commerce is unconstitutional, it is not cured by including in its provisions subjects within the jurisdiction of the state. Nor is a rule prescribed for carriage of goods through, out of, or into a state, any the less a regulation of transportation because the same rule may be applied to carriage which is wholly internal.' This last observation meets the argument that might be made in the present case; namely, that the law is general in its terms, and taxes receipts for all transportation alike, making no discrimination against receipts for interstate or foreign transportation, and hence cannot be regarded as a special tax on the latter. The decision in the case cited shows that this does not relieve the tax from its objectionable character.

If this case stood alone, we should have no hesitation in saying that if would entirely govern the one before us; for, as before said, a tax upon fares and freights received for transportation is virtually a tax upon the transportation itself. But at the same time that the Case of State Freight Tax was decided, the other case referred to, namely, that of State Tax on Railway Gross Receipts, was also decided, and the opinion was delivered by the same member of the court. 15 Wall. 284. This was also a case of a tax imposed upon the Reading Railroad Company. It arose under another act of assembly of Pennsylvania sylvania passed in February, 1866, by which it was enacted that, 'in addition to the taxes now provided by law, every railroad, canal, and transportation company incorporated under the laws of this common wealth, and not liable to the tax upon income under existing laws, shall pay to the commonwealth a tax of three-fourths of one per centum upon the gross receipts of said company. The said tax shall be paid semi-annually.' Under this statute the accounting officers of Pennsylvania stated an account against the Reading Railroad Company for tax on gross receipts of the company for the half year ending December 31, 1867. These receipts were derived partly from the freight of goods transported wholly within the state and partly from the freight of goods exported to points without the state, which latter were discriminated from the former in the reports made by the company. It was the tax on the latter receipts which formed the subject of controversy. The same line of argument was taken at the bar as in the other case. This court, however, held the tax to be constitutional. The grounds on which the opinion was based, in order to distinguish this case from the preceding one, were two:

First, that the tax, being collectible only once in six months, was laid upon a fund which had become the property of the company, mingled with its other property, and incorporated into the general mass of its property, possibly expended in improvements or otherwise invested. The case is likened, in the opinion, to that of taxing goods which have been imported after their original packages have been broken, and after they have been mixed with the mass of property in the country, which, it was said, are conceded in Brown v. Maryland to be taxable. This reasoning seems to have much force. But is the analogy to the case of imported goods as perfect as is suggested? When the latter become mingled with the general mass of property in the state, they are not followed and singled out for taxation as imported goods, and by reason of their being imported. If they were, the tax would be as unconstitutional as if imposed upon them while in the original packages. When mingled with the general mass of property in the state, they are taxed in the same manner as other property possessed by its citizens, without discrimination or partiality. We held in Welton v. Missouri, 91 U. S. 275, that goods brought into a state for sale, though they thereby become a part of the mass of its property, cannot be taxed by reason of their being introduced into the state, o because they are the products of another state. To tax them as such was expressly held to be unconstitutional. The tax in the present case is laid upon the gross receipts for transportation as such. Those receipts are followed, and caused to be accounted for by the company dollar for dollar. It is those specific receipts, or the amount thereof, (which is the same thing,) for which the company is called upon to pay the tax. They are taxed, not only because they are money or its value, but because they were received for transportation. No doubt a ship-owner, like any other citizen, may be personally taxed for the amount of his property or estate, without regard to the source from which it was derived, whether from commerce or banking or any other employment. But that is an entirely different thing from laying a special tax upon his receipts in a particular employment. If such a tax is laid, and the receipts taxed are those derived from transporting goods and passengers in the way of interstate or foreign commerce, no matter when the tax is exacted, whether at the time of realizing the receipts, or at the end of every six months or a year, it is an exaction aimed at the commerce itself, and is a burden upon it, and seriously affects it. A review of the question convinces us that the first ground on which the decision in State Tax on Railway Gross Receipts was placed is not tenable; that it is not supported by anything decided in Brown v. Maryland; but, on the contrary, that the reasoning in that case is decidedly against it.

The second ground on which the decision referred to was based was that the tax was upon the franchise of the corporation granted to it by the state. We do not think that this can be affirmed in the present case. It certainly could not have been intended as a tax on the corporate franchise, because, by the terms of the act, it was laid equally on the corporations of other states doing business in Pennsylvania. If intended as a tax on the franchise of doing business,—which in this case is the business of transportation in carrying on interstate and foreign commerce,—it would clearly be unconstitutional.

It was held by this court in the case of Gloucester Ferry Co. v. Pennsylvania, 114 U. S. 196, 5 Sup. Ct. Rep. 826, that interstate commerce carried on by corporations is entitled to the same protection against state exactions which is given to such commerce when carried on by individuals. In that case the tax was laid upon the capital stock of a ferry company incorporated by New Jersey, and engaged in the business of transporting passengers and freight between Camden, in New Jersey, and the city of Philadelphia. The law under which the tax was imposed was passed by the legislature of Pennsylvania on the seventh of June, 1879, and declared 'that every company or association whatever, now or hereafter incorporated by or under any law of this common wealth, or now or hereafter incorporated by any other state or territory of the United States or foreign government, and doing business in this commonwealth, * * * [with certain exceptions named,] shall be subject to and pay into the treasury of the common wealth annually a tax, to be computed as follows, namely.' The amount of tax is then rated by the dividends declared, and imposed upon the capital stock of the company at the rate of so many mills, or fractions of a mill, for every dollar of such capital stock. It was contended that the ferry company could not hold property in Philadelphia for the purpose of carrying on its ferrying business, and could not carry on its said business there without a franchise, express or implied from the state of Pennsylvania. But this court held in its opinion, delivered by Mr. Justice FIELD, that the business of landing and receiving passengers and freight at the wharf in Philadelphia was a necessary incident to and a part of their transportation across the Delaware river from New Jersey; that without it that transportation woud be impossible; that a tax upon such receiving and landing of passengers and freight is a tax upon their transportation,—that is, upon the commerce between the two states involved in such transportation; and that congress alone can deal with such transportation,—its non-action being equivalent to a declaration that it shall remain free from burdens imposed by state legislation. The opinion proceeds as follows: 'Nor does it make any difference whether such commerce is carried on by individuals or corporations. Welton v. Missouri, 91 U. S. 275; Mobile v. Kimball, 102 U. S. 691. AS WAS SAID IN PAul V. virginia, 8 wall. 168, at the time of the forming of the constitution a large part of the commerce of the world was carried on by corporations; and the East India Company, the Hudson Bay Company, the Hamburgh Company, the Levant Company, and the Virginia Company were mentioned as among the corporations which, from the extent of their operations, had become celebrated throughout the commercial world. The grant of power [to congress] is general in its terms, making no reference to the agencies by which commerce may be carried on. It includes commerce by whomsoever conducted, whether by individuals or corporations.' 114 U. S. 204, 5 Sup. Ct. Rep. 828. Again: 'While it is conceded that the property in a state belonging to a foreign corporation engaged in foreign or interstate commerce may be taxed equally with like property of a domestic corporation engaged in that business, we are clear that a tax or other burden imposed upon the property of either corporation because it is used to carry on that commerce, or upon the transportation of persons or property, or for the navigation of the public waters over which the transportation is made, is invalid and void as an interference with and obstruction of the power of congress in the regulation of such commerce.' 114 U. S. 211, 5 Sup. Ct. Rep. 832. It is hardly necessary to add that the tax on the capital stock of the New Jersey Company, in that case, was decided to be unconstitutional, because, as the corporation was a foreign one, the tax could only be construed as a tax for the privilege or franchise of carrying on its business, and that business was interstate commerce.

The decision in this case, and the reasoning on which it is founded, so far as they relate to the taxation of interstate commerce carried on by corporations, apply equally to domestic and foreign corporations. No doubt, the capital stock of the former, regarded as inhabitants of the state, or their property, may be taxed as other corporations and inhabitants are, provided no discrimination be made against them as corporations carrying on foreign or interstate commerce, so as to make the tax, in effect, a tax on such commerce. But their business as carriers in foreign or interstate commerce cannot be taxed by the state under the plea that they are exercising a franchise.

There is another point, however, which may properly deserve some attention. Can the tax in this case be regarded as an income tax? And, if it can, does that make any difference as to its constitutionality? We do not think that it can properly be regarded as an income tax. It is not a general tax on the incomes of all the inhabitants of the state, but a special tax on transportation companies. Conceding, however, that an income tax may be imposed on certain classes of the community, distinguished by the character of their occupations, this is not an income tax on the class to which it refers, but a tax on their receipts for transportation only. Many of the companies included in it may and undoubtedly do have incomes from other sources, such as rents of houses, wharves, stores, and water-power, and interest on moneyed investments. As a tax on transportation, we have already seen from the quotations from the State Freight Tax Case that it cannot be supported where that transportation is an ingredient of interstate or foreign commerce, even though the a w imposing the tax be expressed in such general terms as to include receipts from transportation which are properly taxable. It is unnecessary, therefore, to discuss the question which would arise if the tax were properly a tax on income. It is clearly not such, but a tax on transportation only.

The corporate franchises, the property, the business, the income of corporations created by a state may undoubtedly be taxed by the state; but, in imposing such taxes, care should be taken not to interfere with or hamper, directly or by indirection, interstate or foreign commerce, or any other matter exclusively within the jusisdiction of the federal government. This is a principle so often announced by the courts, and especially by this court, that it may be received as an axiom of our constitutional jurisprudence. It is unnecessary, therefore, to review the long list of cases in which the subject is discussed. Those referred to are abundantly sufficient for our purpose. We may add, however, that, since the decision of the Railway Tax Cases now reviewed, a series of cases has received the consideration of this court, the decisions in which are in general harmony with the views here expressed, and show the extent and limitations of the rule that a state cannot regulate or tax the operations or objects of interstate or foreign commerce. We may refer to the following: Railroad Co. v. Husen, 95 U. S. 465; Cook v. Pennsylvania, 97 U. S. 566; Guy v. Baltimore, 100 U. S. 434; Webber v. Virginia, 103 U. S. 344; Moran v. New Orleans, 112 U. S. 69, 5 Sup. Ct. Rep. 38; Walling v. michigan, 116 U. S. 446, 6 Sup. Ct. Rep. 454; Pickard v. Pullman Co., 117 U. S. 34, 6 Sup. Ct. Rep. 635; Wabash R. Co. v. Illinois, 118 U. S. 557, ante, 4; Robbins v. Taxing-Dist. Shelby Co., 120 U. S. 489, ante, 592; Fargo v. Michigan, 121 U. S. 230, ante, 857. The cases of Moran v. New Orleans and Fargo v. Michigan are especially apposite to the case now under consideration. As showing the power of the states over local matters incidentally affecting commerce, see Munn v. Illinois, 94 U. S. 123, and other cases in the same volume, pages 161, 176, 180, as explained by Wabash Co. v. Illinois; The Wharfage Cases, viz., Packet Co. v. Keokuk, 95 U. S. 80; Same v. St. Louis, 100 U. S. 428; Same v. Catlettsburg, 105 U. S. 563; Transportation Co. v. Parkersburg, 107 U. S. 698, 2 Sup. Ct. Rep. 732; 121 U. S. ——; Mobile v. Kimball, 102 U. S. 691; Brown v. Houston, 114 U. S. 622, 630, 5 Sup. Ct. Rep. 1091; Railroad Commission Cases, 116 U. S. 307, 6 Sup. Ct. Rep. 334, 348, 349, 388, 391, 1191; Coe v. Errol, 116 U. S. 517, 6 Sup. Ct. Rep. 475.

It is hardly within the scope of the present discussion to refer to the disastrous effects to which the power to tax interstate or foreign commerce may lead. If the power exists in the state at all, it has no limit but the discretion of the state, and might be exercised in such a manner as to drive away that commerce, or to load it with an intolerable burden, seriously affecting the business and prosperity of other states interested in it; and if those states, by way of retaliation, or otherwise, should impose like restrictions, the utmost confusion would prevail in our commercial affairs. In view of such a state of things which actually existed under the confederation, Chief Justice MARSHALL, in the case before referred to, said: 'Those who felt the injury arising from this state of things, and those who are capable of estimating the influence of commerce of the prosperity of nations, perceived the necessity of giving the control over this important subject to a single government. It may be doubted whether any of the evils proceeding from the feebleness of the federal government contributed more to that great revolution which introduced the present system than the deep andg eneral conviction that commerce ought to be regulated by congress. It is not, therefore, matter of surprise that the grant should be as extensive as the mischief, and should comprehend all foreign commerce, and all commerce among the states. To construe the power so as to impair its efficacy would tend to defeat an object, in the attainment of which the American public took, and justly took, that strong interest which arose from a full conviction of its necessity.' 12 Wheat. 446. Nothing can be added to the force of these words.

Our conclusion is that the imposition of the tax in question in this cause was a regulation of interstate and foreign commerce, in conflict with the exclusive powers of congress under the constitution. The judgment of the supreme court of Pennsylvania is therefore reversed, and the case is remanded to be disposed of according to law, in conformity with this opinion.