delivered the opinion of the Court:

He who applies for a mandamus must clearly establish his right to it. Ex parte Fleming, 2 Wall. 759, 17 L. ed. 924. It is not a writ of right. United States ex rel. Turner v. Fisher, 222 U. S. 204, 209, 56 L. ed. 165, 168, 32 Sup. Ct. Rep. 37; Garfield v. United States, 31 App. D. C. 332, 335. At the very outset the right of the relater to maintain the action is challenged. He does not allege that the druggist would refill the prescription if it were not for the decision of the Treasury officials. For aught that appears the druggist may have had many reasons, other than the one assigned, for his refusal. If he had, then the granting of the mandamus would not secure to the relater what he desires, for the druggist might still refuse; and if it would not, the relater has not a direct legal interest in the relief which he seeks. There is nothing in Truax v. Raich, 239 U. S. 33, 60 L. ed. 131, L.R.A.1916D, 545, 36 Sup. Ct. Rep. 7, Ann. Cas. 1917B, 283, in conflict with this. In that case Raich brought suit against his employer, Truax, and certain state officers of Arizona, alleging that, under a statute of that State requiring every employer of more than five workers at one time to employ not fess than 80 per cent of qualified electors, his employer was about to discharge him, he not being a qualified elector, for the sole reason that, if he *75was not discharged, the employer would be punished under the statute», which was a criminal one. Ivaich asked for an injunction restraining the defendants from acting under the statute. It was claimed by the state officers that as Itaich was an employee at will, his employer might discharge him at any time irrespective of the statute; that the injunction would not save for him his position, and therefore he had no direct legal interest in securing it. But the court rejected this argument and said: “It sufficiently appears that the discharge of the complainant will be solely for the purpose of meeting of the requirements of the act and avoiding threatened prosecution under its provisions.” There is no allegation here, as we have observed, that the druggist refused to refill the prescription solely because of the Treasury decision. While we are of the opinion that the relater, for the reasons stated, has no right to maintain this action, we are not willing to place our judgment upon that ground alone.

Where executive officers of the government are directed by an act of Congress to interpret the act for any purpose, and there is room for more than one; construction, the action of the officials in selecting the one rather than the other will not be interfered with by the courts through mandamus. In such a case, the officers exercise a discretion lodged in them by the legislature, and the courts have no power to control the exercise of that discretion. If they had, then it would be their judgment, and not the judgment of the executive officers, which would prevail, although Congress had directed otherwise.

In Decatur v. Paulding, 14 Pet. 497, 515, 10 L. ed. 559, 568, it vras said: “The court could not entertain an appeal from the decision of one of the secretaries, nor revise his judgment in any case where the law authorized him to exercise discretion or judgment. Nor can it, by mandamus, act directly upon the officer, and guide and control his judgment or discretion in tire matters committed to his care, in the ordinary discharge of his official duties. * * * The interference of the courts with the performance of the ordinary duties of the executive departments of the government would be productive of nothing but mischief; and we are quite satisfied that such *76a power was never intended to, be given to them.” See also Handel v. Lane, 45 App. D. C. 389; United States ex rel. Ness v. Fisher, 223 U. S. 683, 56 L. ed. 610, 32 Sup. Ct. Rep. 356. Of course, as was said in Lane v. Hoglund, 244 U. S. 174, 61 L. ed. 1066, 37 Sup. Ct. Rep. 558, quoting with approval from Roberts v. United States, 176 U. S. 221, 44 L. ed. 443, 20 Sup. Ct. Rep. 376: “If the law direct him [an executive officer] to perform an act in regard to which no discretion is committed to him, and which, upon the facts existing, he is bound to perform, then that act is ministerial, although depending upon a statute which requires, in some degree, a construction of its language by the officer.” In other words, where there is no discretion given to the executive officer, the act is ministerial, and, of course, subject to control by the courts. Mississippi v. Johnson, 4 Wall. 475, 18 L. ed. 437. But where the power granted is not ministerial, but discretionary, tHe officer is free to adopt any of the positions warranted by the statute he is called upon to construe, and in such case the courts will not revise his judgment. It is equally true, as said in the Roberts Case, supra, that the courts are always “reluctant to award or sustain a writ of mandamus against an executive officer.”

Having these rules to guide us, we proceed to inquire whether or not the language of the statute under analysis is susceptible of more than one meaning, and, if so, whether the decision of the Treasury officials in question falls within one of the meanings.

The act is a revenue measure whose constitutionality has been sustained. United States v. Jin Fuey Moy, 241 U. S. 394, 60 L. ed. 1061, 36 Sup. Ct. Rep. 658. As we have already observed, it makes two exceptions inter alia from its requirements that the drug shall be dispensed only on orders written on blanks purchased from the Commissioner of Internal Eevenue; namely, when it is dispensed (a) on “prescriptions,” and (b) in “preparations and remedies.” Eelator puts his argument against the decision of the Treasury officials on two grounds: (1) That the duty imposed Upon them by the act is simply ministerial, and (2) that their decision is in derogation of the statute.

*77The contentions for and against him may be arranged in two categories.

First: On his behalf it is said that when a physician gives written directions for the drug unassociated with other elements, it is a “prescription” within the meaning of sec. 2, subdivision b, but when his directions call for the drug in association with other elements' it is not a “prescription,” but a “preparation” or a “remedy,” according to sec. 6; that unless this view’ is taken we shall have a situation in which a druggist may not refill a prescription for the amount of the drug exempt under sec. G, but may freely dispense that amount of the drug in the form of a preparation or remedy; and that a construction which -would lead to such a result would be unreasonable and hence must be rejected. It is further asserted that if this view be not correct, the term “prescription” in subdivision b, when properly understood, does not mean the written directions of the physician, dentist, or veterinary surgeon, but comprehends the mixture of drugs prepared by the pharmacist in response to such directions, and is therefore a preparation or a remedy within the-meaning of sec. 6; and finally that whichever one of these views is right, a prescription, such as relator’s, which does not contain more than the permitted amount of the drug under that section, is not subject to the act, and may be refilled as often as desired.

Second: On the other hand it is claimed that the statute distinguishes “prescriptions” from “preparations and remedies,” making the one subject to some of its provisions and excluding the other, but does not make any distinction between prescriptions themselves, as contended for by relator, — that all prescriptions are treated alike; that it is competent for Congress in a revenue act to fix the conditions upon which it will exempt certain articles from the fee or charge otherwise required; that if in doing so, as in the act before us, it discriminates between cases in -which the drug is dispensed on a prescription of a physician, dentist, or veterinarian, and those in which it is dispensed as a part of a “preparation and remedy,” no one has a right to complain unless it be the dealer against whom the discrimination is made; that the word “prescription” has two *78meanings, — one comprehending the written directions of the physician and the other the drug compound prepared in compliance with his directions (Webster’s Diet.) ; that the term is used in subdivision b according to the first sense, for it provides that the prescription must be dated, signed, and filed, and these requirements indicate that the written _ directions, and not the compound, are intended, because the latter cannot be dated, signed, and filed; that the filling of the prescription executes it; and that the prescription ceases to have any force after that, and hence cannot be refilled; also that since the act may be assumed, according to the Supreme Court of the United States, to have “a moral end as well as a revenue in view” (United States v. Jin Fuey Moy, 241 U. S. 402, 60 L. ed. 1064, 36 Sup. Ct. Rep. 658, and since no one not registered can procure the drug except upon the judgment of a physician, dentist, or veterinary surgeon, expressed in .writing in the form of a prescription, that his patient’s health requires it at the time of issuing the prescription, this would be defeated at least in large part if the patient could have it refilled whenever he pleased irrespective of whether it was for his benefit or not.

Both lines of argument have, we think, a basis in the statute, and we mention them not for the purpose of indicating our opinion as to which one is correct, but to show that the statute is open to at least two constructions, and that the Treasury officials in adopting one rather than the other did that which they were authorized to do, and hence their action is not subject to our control.

For the reasons given in the foregoing.opinion, the judgment is affirmed at the costs of the appellant. Affirmed.

dissenting:

There is an averment in both the petition and the amended petition that the refusal of the druggist to refill the prescription was because he “could not legally refill the same under Treasury decision 2309.” In other words, according to this averment the' sole reason assigned by the druggist for his refusal to refill this prescription was the existence of Treasury decision 2309, which' *79in effect prohibits such refilling. I think this averment is sufficient to bring the case within the rule in Truax v. Raich, 239 U. S. 33, 60 L. ed. 131, L.R.A.1916D, 545, 36 Sup. Ct. Rep. 1, Ann. Cas. 1917R, 283, where an employee was discharged by his employer because of fear of the penalties that otherwise wpuld have been incurred. The court said: “It sufficiently appears that the discharge of the complainant will be solely for the purpose of meeting of the requirements of the act and avoiding threatened prosecution under its provisions. It is therefore idle to call the injury indirect or remote.”

The first five sections of the Harrison Act deal with certain narcotic drugs, or any compounds or derivatives thereof. The intent of Congress in these sections was carefully to restrict the sale or distribution of such habit-forming drugs. Section 6, however, with which we here are concerned, expressly exempts from the provisions of the act “preparations and remedies” which do not contain more than a specified amount of such drugs, provided that “such remedies and preparations” are used solely as medicines. It thus appears that the first five sections deal with certain drugs when sold as such, while sec. 6 deals with remedies one of the ingredients of which is a drug mentioned in the preceding sections.

The Treasury Department promulgated said regulation No. 2309, under which the exemptions in sec. 6 are declared to “apply exclusively to ready-made preparations and remedies prepared in accordance with the United States Pharmacopeia, National Formulary, or other recognized or established formulary, usually carried in stock by the dealer and sold without a prescription,” etc. In other words, had the druggist who filled appellant’s prescription been sufficiently impressed with its merit to warrant him in placing the remedy or preparation on the market, and thereupon had made up a quantity of bottles to supply the anticipated demand, he might have passed out one of those bottles to appellant when he applied to have his prescription re,filled, without incurring the pains and penalties of the law. This must be so, because admittedly this particular remedy contains less than the prescribed amount of the habit-forming drugs mentioned in see. G, and admittedly was to be *80used by appellant solely as a medicine. The above illustration, in my view, demonstrates the unreasonableness of the position of the Treasury Department. The effect of the Treasury decision in question is to discriminate against preparations and remedies prescribed by reputable physicians, in favor of patent medicines. Of course, the druggist is powerless, and must subordinate his will to that of the Treasury Department, or suffer prosecution.

Believing that the view of the Department is so unreasonable as to be arbitrary, and hence within the power of the court to control (Lane v. Hoglund, 244 U. S. 174, 61 L. ed. 1066, 37 Sup. Ct. Rep. 558,), I respectfully dissent.

A motion for a rehearing was denied August 12, 1918.