
233 S.E.2d 544 (1977)
292 N.C. 294
STATE of North Carolina
v.
Andrew Arthur BEST.
No. 32.
Supreme Court of North Carolina.
April 14, 1977.
*549 Rufus L. Edmisten, Atty. Gen., by Joan H. Byers, Associate Atty., Raleigh, for the State of N. C.
James, Hite, Cavendish & Blount by Marvin Blount, Jr., Greenville, of counsel for defendant-appellant.
HUSKINS, Justice:
The defendant, Dr. Best, was arrested on 26 March 1975, pursuant to a warrant charging him with violation of G.S. 90-95(a)(1). That statute reads in pertinent part as follows:
"(a) Except as authorized by this Article, it is unlawful for any person:
(1) To manufacture, sell or deliver. . . a controlled substance;"
(Emphasis added.)
Defendant was indicted and convicted under charges that on two occasions he "unlawfully and wilfully did feloniously sell and deliver a controlled substance, to wit: Methylphenidate in the form of Ritalin, which is included in Schedule II of the North Carolina Controlled Substances Act, not within the normal course of his professional practice, to M. T. Owens, Special Agent, SBI, Diversion Investigative Unit." (Emphasis added.)
Evidence elicited at trial tends to show that on 27 February 1975 and 19 March 1975 Dr. Best gave prescriptions to SBI Agent M. T. Owens for Ritalin, a Schedule II Controlled Substance. The State produced one expert witness who stated that under similar circumstances, related in a hypothetical question, the conduct of the doctor in prescribing the drug was outside the normal course of professional practice in North Carolina and not for a legitimate medical purpose.
At the close of the State's evidence defendant's motion to dismiss was denied. This motion was renewed at the close of all the evidence and is properly before this Court. State v. Rigsbee, 285 N.C. 708, 208 S.E.2d 656 (1974).
We have said that a defendant must be convicted, if at all, of the particular offense charged in the bill of indictment. "Whether there is a fatal variance between the indictment and the proof is properly presented by defendant's motion to dismiss." State v. Cooper, 275 N.C. 283, 167 S.E.2d 266 (1969); State v. Bell, 270 N.C. 25, 153 S.E.2d 741 (1967). Thus the threshold question presented by this case is whether the offense charged conforms to the evidence elicited; that is, does the action of a physician in prescribing a controlled substance amount to a "sale or delivery" as proscribed by G.S. 90-95(a)(1)? For the reasons which follow, we hold that it does not.
The North Carolina Controlled Substances Act (Article 5 of Chapter 90 of the General Statutes) is not a model of clarity *550 or good draftmanship and, with respect to particular applications, its interpretation is clouded by gaps and inconsistencies. Analysis of the entire Act compels the conclusion that the Legislature has established parallel systems of regulation for controlled substances. The separate systems are distinguished according to the nature of the transaction and the status of the individuals involved. Simply put, one system applies to "street traffickers," while the second regulates the dispensation of controlled drugs for legitimate medical purposes. Within each system there are further gradations, based generally on the seriousness of the drug involved and the nature of the transaction. For example, compare G.S. 90-95(b)(1) with G.S. 90-95(b)(2) and G.S. 90-95(b) with G.S. 90-95(c).
Prior to 1971, drug transactions were regulated in North Carolina through the Uniform Narcotic Drug Act, Article 5 of Chapter 90 of the General Statutes (1965), and Barbiturate and Stimulant Drugs, Article 5A of Chapter 90 of the General Statutes (1965). Under that scheme, the statute under which a defendant was prosecuted was determined by the nature of the drug involved. Thus under Article 5 it was unlawful for a person to "manufacture, possess, have under his control, sell, prescribe, administer, dispense, or compound any narcotic drug, except as authorized . . .." G.S. 90-88 (1965). "Narcotic drugs" included coca leaves, opium, cannabis, and others chemically similar. G.S. 90-87(9) (Cum. Supp.1969). Prescribing, administering and dispensing were specifically authorized when done in good faith and in the course of professional practice. G.S. 90-94 (1965). The penalty for a first violation of that article was a fine of not more than $1,000 or imprisonment for not more than five years. G.S. 90-111 (Cum.Supp.1969). Penalties for subsequent violations were higher.
In 1971 the Legislature made basic changes in North Carolina drug laws, bringing them into closer alignment with Federal law, 21 U.S.C. §§ 801, et seq., and with the Uniform Controlled Substances Act found in Volume 9 of The Uniform Laws, Annotated.
In skeletal form the present system of control over physicians operates as follows: (1) All transactions with controlled substances are prohibited by G.S. 90-95 except as authorized. (2) Under G.S. 90-101 a physician who meets established objective criteria is authorized to make certain transactions with controlled substances and thus is exempted from the proscriptions of G.S. 90-95. (3) Control is reasserted under G.S. 90-108 whereby the physician's actions with respect to these transactions must be within the normal course of professional practice in this State and for a legitimate medical purpose. We now look at the scheme in more detail.
We initially note that in the 1971 enactment, schedules were set up classifying various drugs based upon potential for abuse and accepted medical use. See G.S. 90-88 to 94. Then by enactment of G.S. 90-95 (Cum.Supp.1971), the General Assembly provided as follows:
"(a) Except as authorized by this Article, it shall be unlawful for any person:
(1) To manufacture, distribute or dispense or possess with intent to distribute a controlled substance listed in any schedule of this Article;
(2) To create, distribute or possess with intent to distribute a counterfeit controlled substance included in any schedule of this Article;
(3) To possess a controlled substance included in any schedule of this Article."
G.S. 90-95 was amended in 1973 to read:
"(a) Except as authorized by this Article, it is unlawful for any person:
(1) To manufacture, sell or deliver, or possess with intent to manufacture, sell or deliver, a controlled substance;
(2) To create, sell or deliver, or possess with intent to sell or deliver, a counterfeit controlled substance;
(3) To possess a controlled substance."
This statute prohibits any person from manufacturing, selling, delivering or possessing *551 with intent to manufacture, sell or deliver, a controlled substance, except as authorized by Article 5. We now examine Article 5 to determine what transactions it authorizes.
G.S. 90-101 in pertinent part provides:
"(b) Persons registered by the North Carolina Drug Authority under this Article (including research facilities) to manufacture, distribute, dispense or conduct research with controlled substances may possess, manufacture, distribute, dispense or conduct research with those substances to the extent authorized by their registration and in conformity with the other provisions of this Article.
(c) The following persons shall not be required to register and may lawfully possess controlled substances under the provisions of this Article:
* * * * * *
(4) Practitioners licensed in North Carolina by their respective licensing boards under Articles 1, 2, 4, 6, 11 and 12 of this Chapter."
By these provisions a registrant is specifically authorized to manufacture, distribute, dispense, or conduct research with certain controlled substances. A practitioner is authorized to dispense and distribute.
We note that under the language of G.S. 90-101(c)(4) a practitioner is only permitted to "possess" controlled substances. Normally the plain words of a statute control; however, where a literal interpretation will lead to an absurd result and contravene the manifest purpose of the statute, the reason and purpose of the law will be given effect and the strict letter disregarded. 7 N.C. Index 2d, Statutes § 5 and cases cited. In this instance it seems apparent that the Legislature intended to permit those practitioners listed in G.S. 90-101(c)(4) not only to possess but also to distribute and dispense controlled substances as authorized by Article 5. Compare G.S. 90-101 with G.S. 90-102(c), G.S. 90-105 and G.S. 90-106.
Thus the registrant or practitioner is, by his status, exempted from the proscriptions of G.S. 90-95. By the language of G.S. 90-101 this exemption is subject only to the requirement that the person claiming the exemption meet the following objective criteria: The person claiming the exemption must be a registrant, G.S. 90-87(25), or not required to register, G.S. 90-101(c)(4); and exemption from the provisions of G.S. 90-95 applies only when (a) persons claiming the exemption are engaged in transactions authorized by their registration and (b) those transactions involve drugs authorized by their registration. G.S. 90-101(b) and (c)(4). A detailed breakdown of particular registration limitations is provided in I North Carolina Administrative Code, ch. 14, §§ .0105 and .0106.
We reemphasize that the standards are objective and, when met, exempt those who qualify from the proscriptions and penalties of G.S. 90-95. We do not construe G.S. 90-101(c)(4) as incorporating a subjective standard through use of the word "practitioners." Subsection (c)(4) is not found in the Uniform Controlled Substances Act or the Federal Controlled Substances Act. It was added in North Carolina law for the purpose of exempting from registration those persons licensed under the articles enumerated in said subsection, to wit: those licensed to practice medicine, dentistry, pharmacy, optometry, veterinary medicine, and podiatry. While technically a non-registrant would be exempted only when he was a "practitioner," and thus exempted only "so long as such activity is within the normal course of professional practice or research in this State," G.S. 90-87(22), the addition of this subjective standard was not intended by the Legislature and we decline to impose it absent such intention. Otherwise the anomalous situation is created whereby those not required to register under G.S. 90-101(c)(4) would be subjected to standards far more stringent and of a fundamentally different nature than the standards imposed on conventional registrants. Such a distinction would be wholly illogical and the law presumes that the Legislature did not intend such a result. Town of Hudson v. City of Lenoir, 279 N.C. *552 156, 181 S.E.2d 443 (1971); King v. Baldwin, 276 N.C. 316, 172 S.E.2d 12 (1970).
Exemption under G.S. 90-101 does not, however, give free rein to the person who has attained the exempt status. As that statute specifically notes, he must act in conformity with the other provisions of Article 5. G.S. 90-108(a)(2) makes it unlawful for any person subject to the registration requirements of G.S. 90-101 "or a practitioner" to "distribute or dispense a controlled substance in violation of G.S. 90-105 or 90-106."
G.S. 90-105 provides:
"Controlled substances included in Schedules I and II of this Article shall be distributed only by a registrant or practitioner pursuant to an order form. Compliance with the provisions of the Federal Controlled Substances Act or its successor respecting order forms shall be deemed compliance with this section."
G.S. 90-106(a) provides:

"Prescriptions and labeling.(a) Except when dispensed directly by a practitioner, other than a pharmacist, to an ultimate user, no controlled substance included in Schedule II of this Article may be dispensed without the written prescription of a practitioner." (Emphasis added.)
"Dispensing" drugs includes the prescribing of them, G.S. 90-87(8); thus, under G.S. 90-106(a) a physician may lawfully prescribe drugs only through a written prescription. Inherent in the definition of a valid "prescription" is the requirement that it be written by a person licensed to dispense and acting within the normal course of professional practice within the State of North Carolina. Compare G.S. 90-87(23) with G.S. 90-87(22). Thus where a physician prescribes Schedule II controlled drugs, not in the normal course of professional practice in this State, he is acting unlawfully and in violation of G.S. 90-106(a). This construction is bolstered by examination of G.S. 90-106 as a whole. Subsection (a), as noted, requires that Schedule II drugs be dispensed only through a written prescription. Subsection (c) provides that Schedule III and IV drugs, with one exception, may be dispensed by a written prescription or an oral prescription promptly reduced to writing. Subsection (d), dealing with Schedule V drugs, has no prescription requirement, yet it specifically states that such drugs may be distributed or dispensed only for a medical purpose. It is inconceivable that the Legislature would have imposed tighter strictures on the dispensing of the less dangerous Schedule V drugs than it imposed on the dispensing of the drugs listed in Schedules II, III and IV. It is reasonable to assume that the Legislature intended all controlled substances to be dispensed only for legitimate medical purposes and it felt no need specifically to enunciate such a standard for Schedules II, III and IV drugs as it had already incorporated the legitimate medical purpose standard into the prescription requirement of subsections (a) and (c).
In addition, we note the provisions of the Code of Federal Regulations, 21 CFR § 1306.04(a) (1975), which are incorporated into our drug law through I North Carolina Administrative Code, ch. 14 § .0301. That section reads in relevant part:
"1306.04 Purpose of issue of prescription.
(a) A prescription for a controlled substance to be effective must be issued for a legitimate medical purpose by an individual practitioner acting in the usual course of his professional practice. The responsibility for the proper prescribing and dispensing of controlled substances is upon the prescribing practitioner, but a corresponding responsibility rests with the pharmacist who fills the prescription. An order purporting to be a prescription issued not in the usual course of professional treatment or in legitimate and authorized research is not a prescription within the meaning and intent of section 309 of the Act (21 U.S.C. 829) and the person knowingly filling such a purported prescription, as well as the person issuing it, shall be subject to the penalties provided for violations of the provisions of law relating to controlled substances." (Emphasis added.)
*553 Under this regulation the "legitimate medical purpose" requirement, implicit in the language of G.S. 90-106, is made explicit. See United States v. Moore, 423 U.S. 122, 96 S.Ct. 335, 46 L.Ed.2d 333 (1975).
We are not unmindful that the parallel system scheme of drug regulation, as discussed in this opinion, has been rejected by other jurisdictions which have construed somewhat similar acts. See e.g., United States v. Moore, supra; United States v. Rosenberg, 515 F.2d 190 (9th Cir. 1975); United States v. Green, 511 F.2d 1062 (7th Cir. 1975); United States v. Badia, 490 F.2d 296 (1st Cir. 1973); United States v. Leigh, 487 F.2d 206 (5th Cir. 1973); United States v. Bartee, 479 F.2d 484 (10th Cir. 1973); State v. Vinson, 298 So.2d 505 (Fla.Dist.Ct. App.1974); see United States v. Ellzey, 527 F.2d 1306 (6th Cir. 1976). However, several aspects of the North Carolina Controlled Substances Act differ from both the Uniform Controlled Substances Act and the Federal Controlled Substances Act and lend credence to the view which we have taken.
It is apparent that the North Carolina Drug Commission, established by G.S. 143B-377 and empowered by G.S. 90-100 to set rules and regulations relating to the registration and control of the manufacture, distribution and dispensing of controlled substances, views Article 5 of Chapter 90 as establishing a parallel system. See N. C. Drug Authority, Practitioner's Drug Law Information (1974); N. C. Drug Authority, Physicians' Reference on Drug Laws and Emergency Treatment (1972). Where an issue of statutory construction arises, the construction adopted by those charged with the execution and administration of the law is relevant and may be considered. MacPherson v. City of Asheville, 283 N.C. 299, 196 S.E.2d 200 (1973), and cases cited.
Further, we note that under Article 5 as enacted in 1971, the basic penalty provisions for a violation of G.S. 90-95(a)(1) and an intentional violation of G.S. 90-108 were essentially the same. Thus our statutory scheme is not burdened by a major problem found in the Federal Controlled Substances Act. The Federal counterpart to G.S. 90-108 provides only minor penalties. Had the Federal Act been construed as implementing parallel systems of control, medical "pushers" would be subject only to those minor penalties. It was presumed by the courts that since Congress recognized the particularly heinous nature of the prohibited conduct, it could not have intended such a result. See United States v. Moore, supra. No such problem exists under the North Carolina Act. On the contrary, the enactment of potentially stiff penalties under G.S. 90-108 indicates that the Legislature felt that the unlawful acts proscribed thereby were more than minor "technical violations" and fixed the punishment accordingly.
Other evidence of legislative intent is found in the 1973 Amendment to G.S. 90-95(a)(1) which changed the words "manufacture, distribute or dispense" to "manufacture, sell or deliver." When a statute is construed with reference to an amendment, it is "presumed that the legislature intended either (a) to change the substance of the original act, or (b) to clarify the meaning of it." Childers v. Parker's, Inc., 274 N.C. 256, 162 S.E.2d 481 (1968). We think the Legislature intended no substantive change in the Act by the 1973 amendment. That amendment, entitled an "Act to Increase the Penalties for Certain Violations of the Controlled Substances Act," 1973 Session Laws, c. 654, § 1, is clearly aimed at revision of the penalty structure for violation of the Act. That no real change was intended by the new wording is also indicated by G.S. 90-96.1, enacted at the same time, which refers to minors "accused with possessing or distributing a controlled substance in violation of G.S. 90-95(a)(1). . .." 1973 Sess.Laws., c. 654, § 3. Had the Legislature intended substantive change by the substitution of the new terms "sell or deliver" in G.S. 90-95(a)(1), it would not have used the old term "distribute" when referring to that subsection.
As no substantive change was intended, it follows that the new words were designed *554 to clarify the meaning of the statute. By the use of "sell or deliver"words of the streetrather than "distribute or dispense" which have technical medical connotations and which are used extensively in those sections relating to regulation of registrants and practitionersthe Legislature intended to clarify and emphasize the dual nature of the regulatory scheme. We therefore conclude that by enacting the North Carolina Controlled Substances Act the Legislature established parallel systems of drug regulationone system, administered through G.S. 90-95, to control those who "sell and deliver" in the streets; the other, administered through G.S. 90-108, to regulate those permitted by law to conduct authorized transactions with controlled substances.
It now becomes our duty to apply these statutes to the case at hand.
Defendant was indicted and tried on the theory that he did "sell and deliver" a controlled substance in violation of G.S. 90-95(a)(1). The evidence, reviewed in the light most favorable to the State, discloses that the defendant was a licensed physician; that he wrote prescriptions for controlled substances; and that he, in doing so, may have acted outside the normal course of professional practice in North Carolina and not for a legitimate medical purpose.
Where a licensed physician merely writes a prescription for a controlled substance listed in Schedules II, III, IV or V, and nothing more, such act is not a violation of G.S. 90-95(a)(1). However, if that prescription is written outside the normal course of professional practice in North Carolina and not for a legitimate medical purpose, the physician violates G.S. 90-108.
Applying this law to the facts as presented it is apparent that while the indictments follow the language of G.S. 90-95(a)(1), the evidence discloses a violation, if at all, of G.S. 90-108.
This is analogous to the problem presented in State v. Kimball, 261 N.C. 582, 135 S.E.2d 568 (1964). In that case the defendant was tried under an indictment which charged that while lawfully confined at a prison camp he feloniously escaped therefrom. The evidence revealed that the defendant failed to return to the prison while on work release. G.S. 148-45(a) made it a crime to escape from prison, while G.S. 148-45(b) specifically made it a crime to fail to return while on work release. Our Court, speaking through Justice Sharp (now Chief Justice), found that the "indictment in this case follows the language of subsection (a), but the evidence discloses a violation of subsection (b)." The Court then stated that defendant would have been entitled to a nonsuit, had he moved for one, "for this fatal variance." (Emphasis added.) Accord, State v. Cooper, 275 N.C. 283, 167 S.E.2d 266 (1969).
We adhere to this reasoning and hold that a fatal variance exists between the allegations and the proof and it was error to deny defendant's motion to dismiss. State v. Harvey, 281 N.C. 1, 187 S.E.2d 706 (1972); State v. Cooper, supra; State v. Bell, 270 N.C. 25, 153 S.E.2d 741 (1967); State v. Kimball, supra; State v. Overman, 257 N.C. 464, 125 S.E.2d 920 (1962); State v. Jackson, 218 N.C. 373, 11 S.E.2d 149 (1940).
For the reasons stated, the decision of the Court of Appeals is reversed. The cause is remanded to that court for entry of an order remanding the action to the Superior Court of Pitt County for entry of judgment dismissing the action.
REVERSED AND REMANDED.
