after making the foregoing statement, delivered the opinion of the court.

The defendants were indicted for grazing sheep on the Sierra Forest Reserve without having obtained the permission required by the regulations adopted by the Secretary of Agriculture. They démurred on the ground that the Forest Reserve Act of 1891 was unconstitutional, in so far as it delegated to the Secretary of Agriculture power to make rules and regulations and máde a violation thereof a penal offense. Their several demurfers were sustained. The Government brought the case here under that clause of the Criminal Appeals Act, (March 2,1907, c. 2564, 34 Stat. 1246,), which allows a writ of error where the "decision complained of was based upon the invalidity of the statute.”

[*515] The Federal courts have been divided on the question as to whether violations of those regulations of the Secretary of Agriculture constitute a crime. The rules were held to be valid for civil purposes in Dastervignes v. United States, 122 Fed. Rep. 30; United States v. Dastervignes, 118 Fed. Rep. 199; United States v. Shannon, 151 Fed. Rep. 863; S. C., 160 Fed. Rep. 870. They were also sustained in criminal prosecutions in United States v. Deguirro, 152 Fed. Rep. 568; United States v. Domingo, 152 Fed. Rep. 566; United States v. Bale, 156 Fed. Rep. 687; United States v. Rizzinelli, 182 Fed. Rep. 675. But the regulations were held to be invalid in United, States v. Blasingame, 116 Fed. Rep. 654; United States v. Matthews, 146 Fed. Rep. 306; Dent v. United States, 8 Arizona, 138.

From the various acts relating to the establishment and management of forest reservations it appears that they were intended “to improve and protect the forest and to secure favorable conditions of water flows.” . It was declared that the acts should not be “construed to prohibit the egress and ingress of actual settlers” residing therein nor “to prohibit any person from entering the reservation for all proper and lawful purposes, including that of prospecting, and locating and developing mineral resources; provided that such persons comply with the rules and regulations covering such .forest reservation. ” (Act of 1897, c. 2, 30 Stat. 36.) It was also declared that the Secretary “may make such rules and regulations and establish such service as will insure the objects of such reservation, namely, to regulate their occupancy and use and to preserve the forests thereon from destruction; and any violation of the provisions of this act or such rules and regulations shall he punished” as is provided in § 5388, c. 3, p. 1044 of the Revised Statutes, as amended.

Under these acts, therefore, any use of the reservation for grazing or other lawful purpose was required to be[*516] subject to the rules and regulations established by the Secretary of Agriculture. To pasture sheep and cattle on the reservation, at will arid without restraint, might interfere seriously with the accomplishment of the purposes for which they were established. But a limited and regulated use for pasturage might not be inconsistent with the object sought to be attained by the statute. The determination of such questions, however, was a matter of administrative detail. What might be harmless in one forest might be harmful to another. What might be injurious at one stage of timber growth, or at one season of the year, might not be so at another.

In the nature of things it was impracticable for Congress to provide general regulations for these various and varying details of management. Each reservation had its peculiar and special features; and in authorizing the Secretary of Agriculture to meet these local conditions Congress wás merely conferring administrative functions upon an agent, and not delegating to him legislative power. The authority actually given was much less than what has been granted to municipalities by virtue of which they make by-laws, ordinances and regulations for the government of towns and cities. Such ordinances do not declare general rules with reference to rights of persons and property, nor do they create or regulate obligations and liabilities, nor declare what shall be crimes nor fix penalties therefor.

By whatever name they are called they refer to matters of local management and local police. Brodbine v. Revere, 182 Massachusetts, 598. They are “not’of legislative character in the highest sense of the term; and as an owner may delegate to his principal agent the right to employ subordinates, giving them a limited discretion, so. it would seem that Congress might rightfully entrust to the local legislature [authorities] the determination of minor matters.” Butte City Water Co. v. Baker, 196 U. S. 126.

[*517] It must be admitted that it is difficult to define the line which separates legislative power to make laws, from administrative authority to make regulations. This difficulty has often been recognized, and was referred to by Chief Justice Marshall in Wayman v. Southard, 10 Wheat. 1, 42, where he was considering the authority of courts to make rules. He there said: “It will not be contended that Congress can delegate to the courts, or to any other tribunals, powers which are strictly and exclusively legislative. But Congress may certainly delegate to others, powers which the legislature may rightfully exercise itself. ” What were these non-legislative powers which Congress could exercise but which might also be delegated to others was not determined, for he said: “The line has not been exactly drawn which separates those important subjects, which must be entirely regulated by the legislature itself, from those of less interest, in which a general provision may be made, and power given to those who are to act under such general provisions to fill up the details. ”

From the beginning of the Government various acts have been passed conferring upon executive officers power to make rules and regulations — not for the government of their departments, but for administering the laws which did govern. None of these statutes could confer legislative power. But when Congress had legislated and indicated its will, it could give to those who were to act-under such general provisions “power to fill up the details” by the establishment of administrative rules and regulations, the violation of which could be punished by fine or imprisonment fixed by Congress, or by penalties fixed by Congress or measured by the injury done.

Thus it is unlawful to charge unreasonable rates or to discriminate between shippers, and the Interstate Commerce Commission has been given authority to make reasonable rates and to administer the law against discrimination. Int. Com. Comm. v. Ill. Cent. R. R., 215 U. S. 452;[*518] Int. Com. Comm. v. Chicago, Rock Island &c. R. R., 218 U. S. 88. Congress provided that after a given date only-cars with drawbars of uniform height should be used in interstate commerce, and then constitutionally- left to the Commission the administrative duty of fixing a uniform standard. St. Louis & Iron Mountain R. R. v. Taylor, 210 U. S. 281, 287. In Union Bridge Co. v. United States, 204 U. S. 364; In re Kollock, 165 U. S. 526; Buttfield v. Stranahan, 192 U. S. 470, it appeared from the statutes involved that Congress had either expressly or by necessary implication made it unlawful, if not criminal, to obstruct navigable streams; to sell unbranded oleomargarine; or to import unwholesome teas. With this unlawfulness as a predicate the executive officers were authorized to make rules and regulations appropriate to the several matters covered by the various acts. A violation of these rules was then made an offense punishable as prescribed by Congress. But in making these regulations the officers did not legislate. They did not go outside of the circle of that which the act itself had affirmatively required to be done, or treated as unlawful if done. But confining themselves within the field covered by the statute they could adopt regulations of the nature they had thus been generally authorized to make, in order to administer the law and carry the statute into effect.

The defendants rely on United States v. Eaton, 144 U. S. 677, where the act authorized the Commissioner to make rules for carrying the statute into effect, but imposed no penalty for failing to observe his regulations. Another section (5) required that the dealer should keep books showing certain facts, and providing that he should conduct his business under such surveillance of officers as the Commissioner might by regulation require. Another section declared that if any dealer should knowingly omit to do any of the things “required by law” he should pay a penalty of .a thousand dollars. Eaton failed to keep the[*519] books required by the regulations. But there was no charge that he omitted “anything required by law,” unless it could be held that the books called for by the regulations were '‘ required by law. ’ ’ The court construed the act as a whole and proceeded on the theory that while a violation of the regulations might have been punished as an offense if Congress had so enacted, it had, in fact, made no such provision so far as concerned the particular charge then under consideration. Congress required the dealer to keep books rendering return of materials and products, but imposed no penalty for. failing so to do. The Commissioner went much further and required the dealer to keep books showing oleomargarine received, from whom received and to whom the same was sold. It was sought to punish the defendant for failing to keep the books required by the regulations. Manifestly this was putting the regulations above the statute. The court showed that when Congress enacted that a certain sort of book should be kept, the Commissioner could not go further and require additional books; or, if he did make such regulation, there was no provision in the statute by which a failure to comply therewith could be punished. It said that, “if Congress intended to make it an' offense for wholesale dealers to omit to keep books and render returns required by regulations of the Commissioner, it would have done so distinctly” — implying that if it had done so distinctly the violation of the regulations would have been an offense.

But the very thing which was omitted in the Oleomargarine Act has been distinctly done in the Forest Reserve Act, which, in terms, provides that “any violation of the provisions of this act or such rules and regulations of the Secretary shall be punished as prescribed in section 5388 of the Revised Statutes as amended.”

In Union Bridge Co. v. United States, 204 U. S. 364, 386, Mr. Justice Harlan, speaking for the court, said:

“By the statute in question Congress declared in effect[*520] that navigation should be freed from unreasonable obstructions arising from bridges of insufficient height, width of span or other defects. It stopped, however, with this declaration of a general rule and imposed upon the Secretary of War the duty of ascertaining what particular cases came within the rule prescribed by Congress, as well as the duty of enforcing the rule in such cases. In performing that duty the Secretary of War will only execute the clearly expressed will of Congress, and will not, in any true sense, exert legislative or judicial power.”

And again he said in Field v. Clark, 143 U. S. 649, 694:

“The legislature cannot delegate its power to make a law, but it can make a law to delegate a power to determine some fact or state of things upon which the law makes, or intends to make its own action depend. To deny this would be to stop the wheels of government. There are many things upon which wise and useful legislation must depend which cannot be known to the lawmaking power, and must, therefore, be a subject of inquiry and determina^tion outside of the halls of legislation.” See also Caha v. United States, 152 U. S. 211; United States v. Bailey, 9 Pet. 238; Cosmos Co. v. Gray Eagle Co., 190 U. S. 309; Oceanic Navigation Co. v. Stranahan, 214 U. S. 333; Roughton v. Knight, 219 U. S. 537 (Decided this Term); Smith v. Whitney, 116 U. S. 167; Ex parte Reed, 100 U. S. 22; Gratiot v. United States, 4 How. 81.

In Brodbine v. Revere, 182 Massachusetts; 598, a boulevard and park board was given authority to make rules and regulations for the control and government of the roadways under its care. It was there held that the provision in the act that breaches of the rules thus made should be breaches of the peace, punishable in any court having jurisdiction, was not a delegation of legislative power which .was unconstitutional. The court called attention to the fact that the .punishment was not fixed by the board, saying that the making of the rules was administrative, while[*521] the substantive legislation was in the statute which provided that they should be punished as breaches of the peace.

That “Congress cannot delegate legislative power to the President is a principle universally recognized as vital to the- integrity and maintenance of the system of government ordained by the Constitution.” Field v. Clark, 143 U. S. 649, 692. But the authority to make administrative rules .is not a delegation of legislative power, nor are such rules raised from an administrative to a legislative character because the violation thereof is punished as a public offense.

It is true that there is no act of Congress which, in express terms, declares that it shall be unlawful to graze sheep on a forest reserve. But the statutes, from which we have quoted, declare, that the privilege of using reserves for “all proper and lawful purposes” is subject to the proviso that the person so using them shall comply “with the rules and regulations covering such forest reservation.” The same act makes it an offense to violate those regulations, that is, to use them otherwise than in accordance with the rules established by the Secretary. Thus the implied license under which the United States had suffered its public domain to be used as a pasture for sheep and cattle, mentioned in Buford v. Houtz, 133 U. S. 326, was curtailed and qualified by Congress, to the extent that such privilege should not be exercised in contravention of the rules and regulations. Wilcox v. Jackson, 13 Pet. 498, 513.

If, after the passage of the act and the promulgation of the rule, the defendants drove and grazed their sheep upon the reserve, in violation of the regulations, they were making an unlawful use of the Government’s property. In doing so they thereby made themselves liable to the penalty imposed by Congress.

It was argued that, even if the Secretary could establish regulations under which a permit was required, there was[*522] nothing in the act to indicate that Congress had intended or authorized him to charge for the privilege of grazing sheep on the reserve. These fees were fixed to prevent excessive grazing and thereby protect the young growth, and native grasses, from destruction, and tó make a slight income with which to meet the expenses of management. In addition to the general power in the act of 1897, already quoted, the act of February 1, 1905, c. 288, p. 628, clearly indicates that the Secretary was authorized to make charges out of which a revenue from forest resources was expected to arise. For it declares that “all money received from the sale of any products or the use of any land or resources of said forest reserve” shall be covered into the Treasury and be applied toward the payment of forest expenses. This act was passed before the promulgation of regulation 45, set out in the indictment.

Subsequent acts also provide that money received from “any source of forest reservation revenue” should be covered into the Treasury, and a part thereof was to be turned over to the treasurers of the respective States to be expended for the benefit of the public schools and public roads in the counties in which the forest reserves are situated.. (C. 2907, 34 Stat. 684, 1270.)

. The Secretary of Agriculture could not make rules and regulations for any and every purpose. Williamson v. United States, 207 U. S. 462. As to those here involved, they all relate to matters clearly indicated and authorized by Congress. The subjects as to which the Secretary can regulate are defined. The lands are set apart as a forest reserve. He is required to make provision to protect them from depredations and from harmful uses. He is authorized “to regulate the occupancy and use and to preserve the forests from destruction.” A violation of reasonable rules regulating the use and occupancy of the property is made a crime, not by the Secretary, but by Congress. The statute, not the Secretary, fixes the penalty.

[*523] The indictment charges, and the demurrer admits that Rule 45 was promulgated for the purpose of regulating the occupancy and use of the public forest reservation and preserving the forest. The Secretary did not exercise the legislative power of declaring the penalty or fixing the punishment for grazing sheep without a permit, but the punishment is imposed by the act itself. The offense is not against the Secretary, but, as the indictment properly concludes-, “contrary to the laws of the United States and the peace and dignity thereof.” The demurrers should have been overruled. The affirmances by a divided court heretofore entered are set aside and the judgments in both cases

Reversed.