The defendant, Robert Chatfield-Taylor, was charged in a multiple count indictment with being a Massachusetts practitioner who unlawfully dispensed a Class B controlled substance1 in violation of the Controlled Substances Act, G. L. c. 94C (1984 ed.). A jury trial commenced in October, 1984, and at the conclusion of the Commonwealth’s evidence, the defendant moved for a required finding of not guilty. See Mass. R. Crim. P. 25, as amended, 389 Mass. 1107 (1983). The judge denied the motion and after presentation of the defendant’s case, the defendant renewed the motion for a required finding of not guilty. Again, the judge denied the motion and he submitted the case to the jury. The jury deliberated for three days without reaching a verdict. The judge declared a mistrial. The defendant moved to stay retrial pending this appeal2 of the denial of his motions for a required finding of not guilty. We transferred the case to this court on our own motion. We conclude that the Commonwealth presented sufficient evidence to sustain a conviction under G. L. c. 94C, and therefore double jeopardy principles do not bar the defendant’s retrial.
We briefly comment on the procedural posture of this case.3 The defendant appeals to this court from the denial of his motions for a required finding of not guilty. He contends that Berry v. Commonwealth, 393 Mass. 793 (1985), permits such an appeal. In Berry, as in this case, the defendant filed a *3motion for a required finding of not guilty at the close of the Commonwealth’s evidence. Id. at 797. The trial judge denied that motion. Because the jury could not reach a verdict, the judge declared a mistrial. Id. at 794. Prior to the second trial, the defendant in Berry filed a motion to dismiss based on the ground that there was insufficient evidence in the first trial, and that a second trial would, therefore, “violate the common law of this Commonwealth against being twice in jeopardy as well as the prohibition against double jeopardy contained in the Fifth Amendment to the United States Constitution.” Jones v. Commonwealth, 379 Mass. 607, 615 (1980). Abney v. United States, 431 U.S. 651, 654-662 (1977). After his motion to dismiss was denied, but prior to retrial, Berry sought relief from a single justice of this court pursuant to G. L. c. 211, § 3. The single justice reported the case to the full court without decision. Berry, supra at 794. The appropriate procedure to obtain review of the denial of a motion to dismiss based on the ground of double jeopardy is to petition for relief from the single justice pursuant to G. L. c. 211, § 3. The petition may not be filed until after the Commonwealth seeks to put the defendant on trial a second time, the defendant files a motion to dismiss, and the judge denies the motion to dismiss. See Jones v. Commonwealth, 379 Mass. 607, 615 (1980); Costarelli v. Commonwealth, 374 Mass. 677, 679 (1978); Thames v. Commonwealth, 365 Mass. 477, 477 (1974).
Although this appeal is not properly before us, the parties have fully briefed and argued the issues presented in this case. A remand to allow the defendant to file a motion to dismiss and appeal from the denial of that motion would needlessly frustrate the administration of justice. Thus, we address the merits of the defendant’s claim. See Appleton v. Hudson, 397 Mass. 812, 813 n.3 (1986); Cronin v. Strayer, 392 Mass. 525, 527 (1984); Wellesley College v. Attorney Gen., 313 Mass. 722, 731 (1943).
In considering the sufficiency of the evidence, the “question is whether, after viewing the evidence in the light most favorable to the prosecution, any rational trier of fact could have found the essential elements of the crime beyond a reasonable *4doubt” (emphasis in original). Commonwealth v. Latimore, 378 Mass. 671, 677 (1979), quoting Jackson v. Virginia, 443 U.S. 307, 318-319 (1979). Evidence and the inferences which may be drawn from the evidence “must be ‘of sufficient force to bring minds of ordinary intelligence and sagacity to the persuasion of [guilt] beyond a reasonable doubt. ’ ” Latimore, supra at 677, quoting Commonwealth v. Cooper, 264 Mass. 368, 373 (1928). We look to the evidence adduced at the close of the Commonwealth’s case. Commonwealth v. Casale, 381 Mass. 167, 168 (1980). Commonwealth v. Kelley, 370 Mass. 147, 150 (1976).
The essential elements of the crime of unlawful dispensing of a controlled substance4 are set out in G. L. c. 94C, § 19, which states that “[a] prescription for a controlled substance [is valid if it is] issued for a legitimate medical purpose by a practitioner acting in the usual course of his professional practice.”5 See Arthurs v. Board of Registration in Medicine, 383 Mass. 299 (1981); Commonwealth v. Eramo, 377 Mass. 912 (1979).6 “Practitioner” is specially defined in § 1 of G. L. c. 94C as “[a] physician, dentist, veterinarian, podiatrist, scientific investigator, or other person registered to distribute [or] dispense ... a controlled substance in the course of professional practice . . . .” The registration referred to in the definition *5of practitioner involves registration with the Commissioner of Public Health.7 The Commonwealth has proceeded on the assumption that, as part of its case, it must prove that the defendant is registered with the Commissioner of Public Health, and so fits the § 1 definition of practitioner.8
We recite the evidence in the light most favorable to the Commonwealth. Although there was no direct evidence that the defendant is a Massachusetts practitioner,9 there was sufficient evidence presented from which the jurors might reasonably infer that the defendant is a Massachusetts practitioner. The Commonwealth presented evidence that the defendant had an office in Brookline. Moreover, there was evidence that the defendant held himself out as a physician. Copies of the defendant’s prescription blanks10 and stationery,* 11 both inscribed with his name followed by the initials “M.D.,” were introduced as exhibits. There was testimony from an investigating trooper that the defendant was treating patients as a psychiatrist. An expert for the Commonwealth further clarified for the jury that a psychiatrist is a physician.12
*6In addition to this evidence concerning the defendant’s status as a physician practicing in Massachusetts, a copy of a Federal Drug Enforcement Administration^ (DEA) order form for a controlled substance with the defendant’s DEA number was admitted by stipulation.13 This order form stated that the defendant was registered with the DEA as a “practitioner.”14 The evidence also showed that the defendant’s prescriptions were regularly accepted and filled at various pharmacies throughout the Commonwealth. Under the Controlled Substances Act, pharmacies have a corresponding duty to fill only those prescriptions issued by Massachusetts practitioners.15
Finally, the judge in his instructions left it to the jury to determine if the Commonwealth proved that the defendant was a Massachusetts practitioner. We think that the evidence, and the reasonable inferences therefrom, were sufficient to permit *7the jurors to conclude that the defendant was a Massachusetts practitioner.16
We add that the prosecutor made this a close issue unnecessarily. The prosecutor merely had to offer a certified copy of the defendant’s registration with the Department of Public Health to prove that the defendant was a Massachusetts practitioner. See supra, note 9. The ease of the proof is indicated by the fact that this is the first case in which this issue has arisen. See, e.g., Commonwealth v. Perry, 391 Mass. 808 (1984); Commonwealth v. Comins, 371 Mass. 222 (1976), cert. denied, 430 U.S. 946 (1977); Commonwealth v. Miller, 361 Mass. 644 (1972). There is no justification for turning proof of the defendant’s status as a “practitioner” into a close issue.
We conclude that the principles of double jeopardy do not bar retrial of the defendant, and remand the case to the Superior Court for further proceedings.
So ordered.