delivered the opinion of the court.

This is a writ of error to the District Court under the Criminal Appeals Act of March 2, 1907, c. 2564, 34 Stat. 1246. Defendants in error were indicted for a violation of the Narcotic Act of December 17, 1914, c. 1, 38'Stat. 785. The indictment charged them with unlawfully selling to another a certain amount of a derivative of opium and a certain amount of a derivative of coca leaves, not in pursuance of any written order on a form issued in blank for that purpose by the Commissioner of Internal Revenue, contrary to the provisions of § 2 of the act. The defendants demurred to the indictment on the ground that it failed to charge that they had sold the inhibited drugs knowing them to be such. The statute does not make such knowledge an element of the offense. The District Court sustained the demurrer and quashéd the indictment. The correctness of this ruling is the question before us.

While the general rule at common law was that the scienter was a necessary element in the indictment and proof of every crime, and this was followed in regard to statutory crimes even where the statutory definition did *252 riot in teriris include it (Reg. v. Sleep, 8 Cox C. C. 472), thfere has been a modification of this view in respect to prosecutions under statutes the purpose of which would be obstructed by such a requirement.. It is a question of legislative intent to be construed by the court. It has been objected that punishment of a person for an act in violation of law when ignorant of the facts making it so, is an- absence of due process of law. But that objection is considered and overruled in Shevlin-Carpenter Co. v. Minnesota, 218 U. S. 57, 69, 70, in which it was held that in the prohibition or punishment of particular acts, the State may in the maintenance of a public policy provide " that he who shall do them shall do them at his peril and will not be heard to plead in defense good faith or ignorance.” Many instances of this are to be found in.regulatory measures in the exercise of what is called the police power where the emphasis of the statute is evidently upon achievement' of' some social betterment rather than the punishment of .the crimes as in cases of mala in se. Commonwealth v. Mixer, 207 Mass. 141; Commonwealth v. Smith, 166 Mass. 370; Commonwealth v. Hallett, 103 Mass. 452; People v. Kibler, 106 N. Y. 321; State v. Kinkead, 57 Conn. 173; McCutcheon v. People, 69 Ill. 601; State v. Thompson, 74 Ia. 119; United States v. Leathers, 6 Sawy. 17; United States v. Thomson, 12 Fed 245; United States v. Mayfield, 1 77 Fed. 765; United States v. 36 Bottles of Gin, 210 Fed. 271; Feeley v. United States, 236 Fed. 903; Voves v. United States, 249 Fed. 191. So, too, in the collection of taxes, the importance to the public of their collection leads the legislature to impose on-the,taxpayer the'burden of finding out the facts upon which Jiis liability to pay depends and meeting it at the peril of punishment. Regina v. Woodrow, 15 M. & W. 404; Bruhn v. Rex, [1909] A. C. 317. Again where one deals with others and his mere negligence may be dangerous to them, as in selling diseased food or poison, the *253 policy of’ the law may, in order to stimulate proper care, require the punishment of the negligent person though he be ignorant of the noxious character of what he sells. Hobbs v. Winchester Corporation, [1910] 2 K. B. 471, 483.

The question before us, therefore, is one of the construction of the statute and of inference of the intent of Congress. ’ The Narcotic Act has been held by this court to be a taxing act with the incidental purpose of minimizing the spread of addiction to the use of poisonous and demoralizing drugs. United States v. Doremus, 249 U. S. 86, 94; United States v. Jin Fuey Moy, 241 U. S. 394, 402.

Section 2 of the Narcotic Act, 38 Stat. 786, we give in part in the margin. 1 It is very evident from a reading of *254 it that the emphasis, of the section is in securing a close supervision of the business of dealing in these- dangerous drugs by the taxing officers of the Government and that it merely uses a criminal penalty to secure recorded evidence of the disposition of such drugs as a means of taxing and restraining the traffic. Its manifest purpose is to require every person dealing in drugs to ascertain at his peril whether that which he sells comes within the inhibition of the statute, and if he sells the inhibited drug in ignorance of its character, to penalize him. Congress weighed the possible injustice of subjecting an- innocent-seller to a penalty against the evil of -exposing innocent purchasers to danger from the drug, and concluded that the latter was the result preferably .to be. avoided. Doubtless considerations as to the' opportunity of the seller to find out the fact and the difficulty of proof of knowledge contributed to this conclusion. We think the demurrer to the- indictment should have been overruled.

Judgment reversed.