Mr. Justice Stewart
delivered the opinion of the Court.
After a jury trial in the United States District Court for the Middle District of Georgia, respondent Jackie Gainey was convicted of violating 26 U. S. C. § 5601 (a)(1) (possession, custody or control of a set up, unregistered still and distilling apparatus) and 26 U. S. C. § 5601 (a) (4) (carrying on “the business of a distiller or rectifier without having given bond as required by law”)- In the course of his instructions the trial judge informed the jury of two statutory provisions which authorize a jury to infer guilt of the substantive offenses from the fact of a defendant’s unexplained presence at the site of an illegal still. The Court of Appeals for the Fifth Circuit reversed the convictions on the ground that these statutory inferences are unconstitutional, because it thought the connection between unexplained presence at an illegal still and the substantive offenses of “possession” and “carrying on” is insufficiently rational to satisfy the due process requirements formulated by this Court in Tot v. United States, 319 U. S. 463. We granted certiorari, sub nom. United States v. Barrett, to review the exercise of the grave power of annulling an Act of Congress. 375 U. S. 962.
If either statutory inference is valid, the judgment of the Court of Appeals must be reversed, because concurrent sentences were imposed by the District Court. Emspak v. United States, 349 U. S. 190, 195; Sinclair v. United States, 279 U. S. 263, 299 (1929). We find the inference authorized by § 5601 (b) (2) constitutionally permissible, and therefore reverse the judgment without reaching the validity of § 5601 (b)(1).
The legislative record shows that Congress enacted these provisions because of “the practical impossibility of proving . . . actual participation in the illegal activities except by inference drawn from [the defendant’s] presence when the illegal acts were committed . ...” The statutes were passed against a backdrop of varying formulations among the Circuits of the standards which should shape a trial judge’s instructions to a jury in telling it what weight to accord the fact of a defendant’s unexplained presence at an illegal still site. Long before 1958, the year the statutes were enacted, trial judges had been instructing juries that a defendant’s presence at a still could be considered by them in determining whether the defendant had participated in carrying on the illegal operation. Barton v. United States, 267 F. 174, 175-176 (C. A. 4th Cir.). Compare Wilson v. United States, 162 U. S. 613. The Fourth Circuit had endorsed such a charge. Barton v. United States, supra. In the Third and Fifth Circuits the precedents were less clear. See Graceffo v. United States, 46 F. 2d 852 (C. A. 3d Cir.); Fowler v. United States, 234 F. 2d 697, 699 (C. A. 5th Cir.).
The variations among the courts of appeals concerned the reasonableness of inferring guilt of the substantive offense from the fact of unexplained presence at the site of the criminal enterprise. It is that question which Congress has now resolved in favor of the established practice of trial judges to include the inference in their charges. And it is the same question of reasonableness which the petitioner asks this Court to determine in passing on the constitutionality of § 5601 (b)(2).
As the Court of Appeals correctly stated in this case, the constitutionality of the legislation depends upon the rationality of the connection “between the facts proved and the ultimate fact presumed.” Tot v. United States, 319 U. S. 463, 466. The process of making the determination of rationality is, by its nature, highly empirical, and in matters not within specialized judicial competence or completely commonplace, significant weight should be accorded the capacity of Congress to amass the stuff of actual experience and cull conclusions from it. As the record in the Circuits shows, courts have differed in assessing the weight to be placed upon the fact of the defendant’s unexplained presence at a still. See United States v. Freeman, 286 F. 2d 262 (C. A. 4th Cir.). Yet it is precisely when courts have been unable to agree as to the exact relevance of a frequently occurring fact in an atmosphere pregnant with illegality that Congress’ resolution is appropriate.
The rationality of the inference provided by § 5601 (b) (2) must be viewed in the context of the broad substantive offense it supports. Section 5601 (a)(4) proscribes “carrying on” the enterprise of illegal distillation — an offense which is one of the most comprehensive of the criminal statutes designed to stop the production and sale of untaxed liquor. See Vukich v. United States, 28 F. 2d 666, 669 (C. A. 9th Cir.). Those who aid and abet the enterpriser come within the statute’s reach by virtue of 18 U. S. C. § 2 (1958 ed.). United States v. Giuliano, 263 F. 2d 582 (C. A. 3d Cir.). Suppliers, haulers, and a host of other functionaries have been convicted under the statute. See United States v. Pritchard, 55 F. Supp. 201 (D. C. W. D. S. C.), aff’d, 145 F. 2d 240 (C. A. 4th Cir.). Congress was undoubtedly aware that manufacturers of illegal liquor are notorious for the deftness with which they locate arcane spots for plying their trade. Legislative recognition of the implications of seclusion only confirms what the folklore teaches — that strangers to the illegal business rarely penetrate the curtain of secrecy. We therefore hold that § 5601 (b) (2) satisfies the test of Tot v. United States, supra.
But it is said that this statute is unconstitutional upon a different ground — that it impinges upon the trial judge’s powers over the judicial proceeding. We cannot agree. Our Constitution places in the hands of the trial judge the responsibility for safeguarding the integrity of the jury trial, including the right to have a case withheld from the jury when the evidence is insufficient as a matter of law to support a conviction. The statute before us deprives the trial judge of none of his normal judicial powers. We do not interpret the provision in the statute that unexplained “presence . . . shall be deemed sufficient evidence to authorize conviction” as in any way invading the province of the judge’s discretion. The language permits the judge to submit a case to the jury on the basis of the accused’s presence alone, and to this extent it constitutes congressional recognition that the fact of presence does have probative worth in the determination of guilt. But where the only evidence is of presence the statute does not require the judge to submit the case to the jury, nor does it preclude the grant of a judgment notwithstanding the verdict. And the Court of Appeals may still review the trial judge's denial of motions for a directed verdict or for a judgment n. o. v.
The statute does not prevent the jury from being “properly instructed on the standards for reasonable doubt.” Holland v. United States, 348 U. S. 121, 139. In this case, the trial judge instructed the jury as follows:
“There is one other matter which I should mention. I charge you that the presence of defendants at a still, if proved, with or without flight therefrom, or attempted flight therefrom, if proved, would be a circumstance for you to consider along with all the other testimony in the case. Of course, the bare presence at a distillery and flight therefrom of an innocent man is not in and of itself enough to make him guilty. It is possible under the law for an innocent man to be present at a distillery, and it is possible for him to run when about to be apprehended, and such an innocent man ought never to be convicted, but presence at a distillery, if you think these men were present, is a circumstance to be considered along with all the other circumstances in the case in determining whether they were connected with the distillery or not. Did they have any equipment with them that was necessary at the distillery? What was the hour of day that they were there? Did the officers see them do anything? Did they make any statements?
“It is your duty to explore this case, analyze the evidence pro and con fairly. Presence at a still, together with other circumstances in the case, if they are sufficient in your opinion to exclude every reasonable conclusion except that they were there connected with the distillery, in an illegal manner, . . . carrying on the business as charged . . . , if you believe those things, would authorize you in finding the defendants guilty.
“And under a statute enacted by Congress a few years back, when a person is on trial for . . . carrying on the business of a distiller without giving bond as required by law, as charged in this case, and the defendant is shown to have been at the site of the place . . . where and at the time when the business of a distiller was engaged in or carried on without bond having been given, under the law such presence of the defendant shall be deemed sufficient evidence to authorize conviction, unless the defendant by the evidence in the case and by proven facts and circumstances explains such presence to the satisfaction of the jury.
“Now this does not mean that the presence of the defendant at the site and place at the time referred to requires the jury to convict the defendant, if the defendant by the evidence in the case, facts and cir-circumstances proved, fails to explain his presence to the satisfaction of the jury. It simply means that a jury may, if it sees fit, convict upon such evidence, as it shall be deemed in law sufficient to authorize a conviction, but does not require such a result.” (Emphasis supplied.)
The jury was thus specifically told that the statutory inference was not conclusive. “Presence” was one circumstance to be considered among many. Even if it found that the defendant had been present at the still, and that his presence remained unexplained, the jury could nonetheless acquit him if it found that the Government had not proved his guilt beyond a reasonable doubt. Holland v. United States, supra. In the absence of the statute, such an instruction to the jury would surely have been permissible. Cf. Wilson v. United States, supra. Furthermore, in the context of the instructions as a whole, we do not consider that the single phrase “unless the defendant by the evidence in the case and by proven facts and circumstances explains such presence to the satisfaction of the jury” can be fairly understood as a comment on the petitioner’s failure to testify. Cf. Bruno v. United States, 308 U. S. 287. The judge’s overall reference was carefully directed to the evidence as a whole, with neither allusion nor innuendo based on the defendant’s decision not to take the stand.
In McNamara v. Henkel, 226 U. S. 520, 525, the Court approved a proceeding which did no more than “accord to the evidence, if unexplained, its natural probative force.” That is all that Congress has done here. We cannot find that the law it enacted violates the Constitution.
Reversed.
The evidence for the prosecution showed that an old Dodge truck with darkened headlights drove up to the site of a secluded still, hidden in a swamp in Dooly County, Georgia. The respondent, Jackie Gainey, left the truck, turned on a flashlight, and walked toward the still. There he was confronted by state and federal revenue agents. The respondent attempted to flee, but after a short chase, he and his waiting colleagues were apprehended. Since the trial, one of Gainey’s co-defendants, Roy Lee Barrett, has died; the other, Cleveland Johns, elected to serve and has completed his sentence.
Section 5601 (b)(1) provides:
“(1) Unregistered stills.
“Whenever on trial for violation of subsection (a) (1) the defendant is shown to have been at the site or place where, and at the time when, a still or distilling apparatus was set up without having been registered, such presence of the defendant shall be deemed sufficient evidence to authorize conviction, unless the defendant explains such presence to the satisfaction of the jury (or of the court when tried without jury).”
Section 5601 (b)(2) provides:
“(2) Failure or refusal of distiller or rectifier to give bond.
“Whenever on trial for violation of subsection (a) (4) the defendant is shown to have been at the site or place where, and at the time when, the business of a distiller or rectifier was so engaged in or carried on, such presence of the defendant shall be deemed sufficient evidence to authorize conviction, unless the defendant explains such presence to the satisfaction of the jury (or of the court when tried without jury).”
These sections were introduced into the Code in 1958. The statutory inferences are modeled after 18 U. S. C. §545 (1958 ed.), originally § 4 of the Smuggling Act of 1866, 14 Stat. 178, 179. Similar wording appears in 21 U. S. C. § 174 (1958 ed.), the Narcotic Drugs Import and Export Act of 1909, 35 Stat. 614, the constitutionality of which was sustained in Yee Hem v. United States, 268 U. S. 178.
A third count charged a violation of § 5602, which prohibits carrying on the business of a distiller with intent to defraud the United States. The Court of Appeals reversed the conviction on this count also, and the Government did not seek review of this reversal. A fourth count, charging that the defendants, in violation of 26 U. S. C. § 5180 (1958 ed.), worked in a distillery on which no sign was placed showing the name of the person engaged in the distilling, resulted in a directed verdict of acquittal.
Hearings before a Subcommittee of the House Committee on Ways and Means on Excise Tax Technical and Administrative Problems, Part 3, p. 95, 84th Cong., 2d Sess.
Bozza v. United States, 330 U. S. 160, contributed to congressional concern. See Hearings, note 4, supra. But that case did not deal with the problem of presence alone as insufficient evidence where the substantive offense is “carrying on” the enterprise of illegal distillation. Bozza’s conviction for “carrying on” the enterprise of illegal distillation was affirmed by this Court.
“Very few of the illicit distillers allow any one, except their most intimate friends, to approach their distilleries. Such places, as a rule, are forbidden ground, for the reason that when the violators are arrested it is a difficult matter to prove them guilty, when so few persons have ever seen them operating their distilleries.” Atkinson, After the Moonshiners, By One of the Raiders, at p. 23.
“The first requisite for an illicit still is a good stream of cool water. . . .
“The next requisite is seclusion. It must be placed where no one ever travels, or even thinks of traveling.” Id., at p. 18.
Indeed the better practice would be to instruct the jurors that they may draw the inference unless the evidence in the case provides a satisfactory explanation for the defendant’s presence at the still, omitting any explicit reference to the statute itself in the charge.