This was a complaint against the plaintiff in error for refusing to sell tickets for the transportation of pupils to and from the public schools at one half the regular fare charged by it, as required by Mass. Rev. Laws, chap. 112, § 72. At the trial the railway company admitted the fact, but set up that the statute was unconstitutional, in that it denied to the company the equal protection of the laws and deprived it of its property without just compensation and without due process of law. In support of this defense it made an offer of proof which may be abridged into the propositions that the regular fare was 5 cents; that during the last fiscal year the actual and reasonable cost of transportation per passenger was 3 86/100 cents, or, including taxes, 4 10/100 cents; that pupils of the public schools formed a considerable part of the passengers carried by it, and that the one street railway expressly exempted by the law transported nearly one half the passengers transported on street railways and received nearly one half the revenue received for such transportation in the commonwealth. The offer was stated to be made for the purpose of showing that the plaintiff in error could not comply with the statute without carrying passengers for less than a reasonable compensation and for less than cost. The offer of proof was rejected, and a ruling that the statute was repugnant to the 14th Amendment was refused. The plaintiff in error excepted and, after a verdict of guilty and sentence, took the case to the supreme judicial court. 187 Mass. 436, 73 N. E. 530. That court overruled the exceptions, whereupon the plaintiff in error brought the case here.

This court is of opinion that the decision below was right. A majority of the court considers that the case is disposed of by the fact that the statute in question was in force when the plaintiff in error took its charter, and confines itself to that ground. The section of the Revised Laws (chap. 112, § 72) was a continuation of Stat. 1900, chap. 197. Rev. Laws, chap. 226, § 2. com. v. Anselvich, 186 Mass. 376, 379, 380, 104 Am. St. Rep. 590, 71 N. E. 790. The act of incorporation went into effect March 15, 1901. Stat. 1901, chap. 159. By the latter act the plaintiff in error was 'subject to all the duties, liabilities, and restrictions set forth in all general laws now or hereafter in force relating to street railways companies, except,' etc. § 1. See also § 2. There is no doubt that, by the law as understood in Massachusetts, at least, the provisions of Rev. Laws, Chap. 112, § 72, Stat. 1900, chap. 197, if they had been inserted in the charter in terms, would have bound the corporation, whether such requirements could be made constitutionally of an already existing corporation or not. The railroad company would have come into being and have consentedto come into being subject to the liability, and could not be heard to complain. Rockport Water Co. v. Rockport, 161 Mass. 279, 37 N. E. 168; Ashley v. Ryan, 153 U. S. 436, 443, 38 L. ed. 773, 777, 4 Inters. Com. Rep. 664, 14 Sup. Ct. Rep. 865; Wight v. Davidson, 181 U. S. 371, 377, 45 L. ed. 900, 903, 21 Sup. Ct. Rep. 616; Newburyport Water Co. v. Newburyport, 193 U. S. 561, 579, 48 L. ed. 795, 800, 24 Sup. Ct. Rep. 553.

If the charter, instead of writing out the requirements of Rev. Laws, 112, § 72, referred specifically to another document expressing them, and purported to incorporate it, of course the charter would have the same effect as if it itself contained the words. If the document was identified, it would not matter what its own nature or effect might be, as the force given to it by reference and incorporation would be derived wholly from the charter. The document, therefore, might as well be an unconstitutional as a constitutional law. See Com. v. Melville, 160 Mass. 307, 308, 35 N. E. 863. But the contents of a document may be incorporated or adopted as well by generic as by specific reference, if only the purport of the adopting statute is clear. Corry v. Baltimore, 196 U. S. 466, 477, 49 L. ed. 556, 562, 25 Sup. Ct. Rep. 297. See Purdy v. Erie R. Co. 162 N. Y. 42, 48 L.R.A. 669, 56 N. E. 508.

Speaking for myself alone, I think that there are considerations on the other side from the foregoing argument that make it unsafe not to discuss the validity of the regulation apart from the supposition that the plaintiff in error has accepted it. See W. W. Cargill Co. v. Minnesota, 180 U. S. 452, 468, 45 L. ed. 619, 626, 21 Sup. Ct. Rep. 423. Therefore I proceed to state my grounds for thinking the statute constitutional irrespective of any disabilities to object to its terms.

The discrimination alleged is the express exception from the act of 1900 of the Boston Elevated Railway Company and the railways then owned, leased, or operated by it. But, in the first place, this was a legislative adjudication concerning a specific road, as in Wight v. Davidson, 181 U. S. 371, 45 L. ed. 900, 21 Sup. Ct. Rep. 616, not a general prospective classification as in Martin v. District of Columbia, 205 U. S. 135, 138, 51 L. ed. 743, 744, 27 Sup. Ct. Rep. 440. A general law must be judged by public facts, but a specific adjudication may depend upon many things not judicially known. Therefore the law must be sustained on this point unless the facts offered in evidence clearly show that the exception cannot be upheld. But the local facts are not before us, and it follows that we cannot say that the legislature could not have been justified in thus limiting its action. Covington & L. Turnp. Road Co. v. Sandford, 164 U. S. 578, 597, 598, 41 L. ed. 560, 566, 567, 17 Sup. Ct. Rep. 198. In the next place, if the only ground were that the charter of the elevated railway contained a contract against the imposition of such a requirement, it would be attributing to the 14th Amendment an excessively nice operation to say that the immunity of a single corporation prevented the passage of an otherwise desirable and wholesome law. It is unnecessary to consider what would be the effect on the statute by construction in Massachusetts if the exception could not be upheld. For, if in order to avoid the Scylla of unjustifiable class legislation, the law were read as universal (see Dunbar v. Boston & P. R. Corp. 181 Mass. 383, 386, 63 N. E. 916), it might be thought by this court to fall into the Charybdis of impairing the obligation of a contract with the elevated road, although that objection might, perhaps, be held not to be open to the plaintiff in error here (New York ex rel. Hatch v. Reardon, 204 U. S. 152, 160, 51 L. ed. 415, 422, 27 Sup. Ct. Rep. 188).

The objection that seems to me, as it seemed to the court below, most serious, is that the statute unjustifiably appropriates the property of the plaintiff in error. It is hard to say that street railway companies are not subjected to a loss. The conventional fare of 5 cents presumably is not more than a reasonable fare, and it is at least questionable whether street railway companies would be permitted to increase it on the ground of this burden. It is assumed by the statute in question that the ordinary fare may be charged for these children or some of them when not going to or from school. Whatever the fare, the statute, fairly construed, means that children going to or from school must be carried for half the sum that would be reasonable compensation for their carriage if we looked only to the business aspect of the question. Moreover, while it may be true that in some cases rates or fares may be reduced to an unprofitable point in view of the business as a whole or upon special considerations (Minneapolis & St. L. R. Co. v. Minnesota, 186 U. S. 257, 267, 46 L. ed. 1151, 1157, 22 Sup. Ct. Rep. 900), it is not enough to justify a general law like this, that the companies concerned still may be able to make a profit from other sources, for all that appears (Atlantic Coast Line R. Co. v. North Carolina Corp. Commission, 206 U. S. 1, 24, 25, 51 L. ed. 933, 944, 945, 27 Sup. Ct. Rep. 585).

Notwithstanding the foregoing considerations I hesitatingly agree with the state court that the requirement may be justified under what commonly is called the police power. The obverse way of stating this power in the sense in which I am using the phrase would be that constitutional rights, like others, are matters of degree, and that the great constitutional provisions for the protection of property are not to be pushed to a logical extreme, but must be taken to permit the infliction of some fractional and relatively small losses without compensation, for some, at least, of the purposes of wholesome legislation. Martin v. District of Columbia, 205 U. S. 135, 139, 51 L. ed. 743, 744, 24 Sup. Ct. Rep. 440; Camfield v. United States, 167 U. S. 518, 524, 42 L. ed. 260, 262, 17 Sup. Ct. Rep. 864.

It the 14th Amendment is not to be a greater hamper upon the established practices of the states im common with other governments than I think was intended, they must be allowed a certain latitude in the minor adjustments of life, even though by their action the burdens of a part of the community are somewhat increased. The traditions and habits of centuries were not intended to be overthrown when that Amendment was passed.

Education is one of the purposes for which what is called the police power may be exercised. Barbier v. Connolly, 113 U. S. 27, 31, 28 L. ed. 923, 924, 5 Sup. Ct. Rep. 357. Massachusetts always has recognized it as one of the first objects of public care. It does not follow that it would be equally in accord with the conceptions at the base of our constitutional law to confer equal favors upon doctors, or working men, or people who could afford to by 1000-mile tickets. Structural habits count for as much as logic in drawing the line. And, to return to taking of property, the aspect in which I am considering the case, general taxation to maintain public schools is an appropriation of property to a use in which the taxpayer may have no private interest, and, it may be, against his will. It has been condemned by some theorists on that ground. Yet no one denies its constitutionality. People are accustomed to it and accept it without doubt. The present requirement is not different in fundamental principle, although the tax is paid in kind and falls only on the class capable of paying that kind of tax,—a class of quasi public corporations specially subject to legislative control.

Thus the question narrows itself to the magnitude of the burden imposed,—to whether the tax is so great as to exceed the limits of the police power. Looking at the law without regard to its special operation I should hesitate to assume that its total effect, direct and indirect, upon the roads outside of Boston, amounted to a more serious burden than a change in the law of nuisance, for example, might be. See further, Williams v. Parker, 188 U. S. 491, 47 L. ed. 559, 23 Sup. Ct. Rep. 440. Turning to the specific effect, the offer of proof was cautious. It was simply that a 'considerable percentage' of the passengers carried by the company consisted of pupils of the public schools. This might be true without the burden becoming serious. I am not prepared to overrule the decision of the legislature and of the highest court of Massachusetts, that the requirement is reasonable under the conditions existing there, upon evidence that goes no higher than this. It is not enough that a statute goes to the verge of constitutional power. We must be able to see clearly that it goes beyond that power. In case of real doubt a law must be sustained.

Mr. Justice Harlan is of opinion that the constitutionality of the act of 1900 is necessarily involved in the determination of this case.

He thinks the act is not liable to the objection that it denies to the railway company the equal protection of the laws. Nor does he think that it can be held, upon any showing made by this record, to be unconstitutional as depriving the plaintiff in error of its property without due process of law. Upon these grounds alone, and independent of any other question discussed, he joins in a judgment of affirmance.

Judgment affirmed.

Mr. Justice Moody, having been of counsel, did not sit in this case.