OPINION

MOSK, J.

In this proceeding for writ of prohibition we are called upon to decide whether an unborn but viable fetus is a "human being" within the meaning of the California statute defining murder (Pen. Code, § 187). We conclude that the Legislature did not intend such a meaning, and that for us to construe the statute to the contrary and apply it to this petitioner would exceed our judicial power and deny petitioner due process of law.

The evidence received at the preliminary examination may be summarized as follows: Petitioner and Teresa Keeler obtained an interlocutory decree of divorce on September 27, 1968. They had been married for 16 years. Unknown to petitioner, Mrs. Keeler was then pregnant by one Ernest Vogt, whom she had met earlier that summer. She subsequently began living with Vogt in Stockton, but concealed the fact from petitioner. Petitioner was given custody of their two daughters, aged 12 and 13 years, and under the decree Mrs. Keeler had the right to take the girls on alternate weekends.

On February 23, 1969, Mrs. Keeler was driving on a narrow mountain road in Amador County after delivering the girls to their home. She met petitioner driving in the opposite direction; he blocked the road with his car, and she pulled over to the side. He walked to her vehicle and began speaking to her. He seemed calm, and she rolled down her window to hear him. He said, "I hear you're pregnant. If you are you had better stay away from the girls and from here." She did not reply, and he opened the car door; as she later testified, "He assisted me out of the car. . . . [I]t wasn't roughly at this time." Petitioner then looked at her abdomen and became "extremely upset." He said, "You sure are. I'm going to stomp it out of you." He pushed her against the car, shoved his knee into her abdomen, and struck her in the face with several blows. She fainted, and when she regained consciousness petitioner had departed.

Mrs. Keeler drove back to Stockton, and the police and medical assistance were summoned. She had suffered substantial facial injuries, as well as extensive bruising of the abdominal wall. A Caesarian section was performed and the fetus was examined in utero. Its head was found to be severely fractured, and it was delivered stillborn. The pathologist gave as his opinion that the cause of death was skull fracture with consequent cerebral hemorrhaging, that death would have been immediate, and that the injury could have been the result of force applied to the mother's abdomen. There was no air in the fetus' lungs, and the umbilical cord was intact.

Upon delivery the fetus weighed five pounds and was 18 inches in length. Both Mrs. Keeler and her obstetrician testified that fetal movements had been observed prior to February 23, 1969. The evidence was in conflict as to the estimated age of the fetus; the expert testimony on the point, however, concluded "with reasonable medical certainty" that the fetus had developed to the stage of viability, i.e., that in the event of premature birth on the date in question it would have had a 75 percent to 96 percent chance of survival.

An information was filed charging petitioner, in count I, with committing the crime of murder (Pen. Code, § 187) in that he did "unlawfully kill a human being, to wit Baby Girl VOGT, with malice aforethought." In count II petitioner was charged with wilful infliction of traumatic injury upon his wife (Pen. Code, § 273d), and in count III, with assault on Mrs. Keeler by means of force likely to produce great bodily injury (Pen. Code, § 245). His motion to set aside the information for lack of probable cause (Pen. Code, § 995) was denied, and he now seeks a writ of prohibition; as will appear, only the murder count is actually in issue. Pending our disposition of the matter, petitioner is free on bail.

I

Penal Code section 187 provides: "Murder is the unlawful killing of a human being, with malice aforethought." The dispositive question is whether the fetus which petitioner is accused of killing was, on February 23, 1969, a "human being" within the meaning of the statute. If it was not, petitioner cannot be charged with its "murder" and prohibition will lie.

Section 187 was enacted as part of the Penal Code of 1872. (1) Inasmuch as the provision has not been amended since that date, we must determine the intent of the Legislature at the time of its enactment. But section 187 was, in turn, taken verbatim from the first California statute defining murder, part of the Crimes and Punishments Act of 1850. (Stats. 1850, ch. 99, § 19, p. 231.) Penal Code section 5 (also enacted in 1872) declares: "The provisions of this code, so far as they are substantially the same as existing statutes, must be construed as continuations thereof, and not as new enactments." We begin, accordingly, by inquiring into the intent of the Legislature in 1850 when it first defined murder as the unlawful and malicious killing of a "human being."

(2) It will be presumed, of course, that in enacting a statute the Legislature was familiar with the relevant rules of the common law, and, when it couches its enactment in common law language, that its intent was to continue those rules in statutory form. ( Baker v. Baker (1859) 13 Cal. 87, 95-96; Morris v. Oney (1963) 217 Cal.App.2d 864, 870 [ 32 Cal.Rptr. 88] .) This is particularly appropriate in considering the work of the first session of our Legislature: its precedents were necessarily drawn from the common law, as modified in certain respects by the Constitution and by legislation of our sister states.

We therefore undertake a brief review of the origins and development of the common law of abortional homicide. (For a more detailed treatment, see Means, The Law of New York Concerning Abortion and the Status of the Foetus, 1664-1968: A Case of Cessation of Constitutionality (1968) 14 N.Y.L.F. 411 [hereinafter cited as Means]; Stern, Abortion: Reform and the Law (1968) 59 J.Crim.L., C. P.S. 84; Quay, Justifiable Abortion — Medical and Legal Foundations II (1961) 49 Geo.L.J. 395.) (3) From that inquiry it appears that by the year 1850 — the date with which we are concerned — an infant could not be the subject of homicide at common law unless it had been born alive. Perhaps the most influential statement of the "born alive" rule is that of Coke, in mid-17th century: "If a woman be quick with childe, and by a potion or otherwise killeth it in her wombe, or if a man beat her, whereby the childe dyeth in her body, and she is delivered of a dead childe, this is a great misprision [i.e., misdemeanor], and no murder; but if the childe be born alive and dyeth of the potion, battery, or other cause, this is murder; for in law it is accounted a reasonable creature, in rerum natura, when it is born alive." (3 Coke, Institutes *50 (1648).) In short, "By Coke's time, the common law regarded abortion as murder only if the foetus is (1) quickened, (2) born alive, (3) lives for a brief interval, and (4) then dies." (Means, at p. 420.) Whatever intrinsic defects there may have been in Coke's work (see 3 Stephen, A History of the Criminal Law of England (1883) pp. 52-60), the common law accepted his views as authoritative. In the 18th century, for example, Coke's requirement that an infant be born alive in order to be the subject of homicide was reiterated and expanded by both Blackstone and Hale.

Against this background, a series of infanticide prosecutions were brought in the English courts in mid-19th century. In each, a woman or her accomplice was charged with murdering a newborn child, and it was uniformly declared to be the law that a verdict of murder could not be returned unless it was proved the infant had been born alive. Thus in Rex v. Brain (1834) 6 Car. P. 349, 350, 172 Eng.Reprint 1272, the court instructed the jury that "A child must be actually wholly in the world in a living state to be the subject of a charge of murder; but if it has been wholly born, and is alive, it is not essential that it should have breathed at the time it was killed; as many children are born alive, and yet do not breathe for some time after their birth. But you must be satisfied that the child was wholly born into the world at the time it was killed, or you ought not to find the prisoner guilty of murder." (Accord, Rex v. Poulton (1832) 5 Car. P. 329, 172 Eng.Reprint 997; Rex v. Enoch (1833) 5 Car. P. 539, 172 Eng.Reprint 1089; Rex v. Crutchley (1836) 7 Car. P. 814, 173 Eng.Reprint 355; Rex v. Sellis (1836) 7 Car. P. 850, 173 Eng.Reprint 370; Reg. v. Reeves (1839) 9 Car. P. 25, 173 Eng.Reprint 724; Reg. v. Wright (1841) 9 Car. P. 754, 173 Eng.Reprint 1039; Reg. v. Trilloe (1842) Car. M. 650, 174 Eng.Reprint 674; see also cases collected in Atkinson, Life, Birth, and Livebirth (1904) 20 L.Q.Rev. 134, 139-145.)

Of these decisions, some pointed out that evidence of breathing is not conclusive because that function may begin before the infant is fully born ( Poulton, Enoch, Sellis), while others observed that the infant can possess an "independent circulation" — one of the tests used to determine live birth — even though the umbilical cord may not yet be severed ( Reeves, Trilloe). But all were in agreement that however live birth was to be proved, unless that event had occurred before the alleged criminal act there could be no conviction of homicide.

By the year 1850 this rule of the common law had long been accepted in the United States. As early as 1797 it was held that proof the child was born alive is necessary to support an indictment for murder ( State v. McKee (Pa.) Addison 1), and the same rule was reiterated on the eve of the first session of our Legislature ( State v. Cooper (1849) 22 N.J.L. 52). Although the precise issue in Cooper was whether an attempted abortion on a woman whose fetus had not yet "quickened" was a common law crime, the opinion begins by a recital of the common law rules on abortional homicide. In its argument the State took the position that attempted abortion was an offense against the person of the child, and the court replied that "the very point of inquiry is, whether that be at all an offense or not, and whether the child be in esse, so that any crime can be committed against its person. In regard to offences against the person of the child, a distinction is well settled between its condition before and after its birth. Thus, it is not murder to kill a child before it be born, even though it be killed in the very process of delivery." ( Id. at p. 54.) In support of this proposition, the court then set out in full each of the passages of Coke, Blackstone, and Hale quoted hereinabove. ( Id. at pp. 54-55.)

While it was thus "well settled" in American case law that the killing of an unborn child was not homicide, a number of state legislatures in the first half of the 19th century undertook to modify the common law in this respect. The movement began when New York abandoned the common law of abortion in 1830. The revisers' notes on that legislation recognized the existing rule, but nevertheless proposed a special feticide statute which, as enacted, provided that "The wilful killing of an unborn quick child, by any injury to the mother of such child, which would be murder if it resulted in the death of such mother, shall be deemed manslaughter in the first degree." (N.Y. Rev. Stat. 1829, pt. IV, ch. 1, tit. 2, § 8, quoted in Means, at p. 443.) At the same time the New York Legislature enacted a companion section (§ 9) which, although punishing a violaton thereof as second degree manslaughter, was in essence an "abortion law" similar to those in force in most states today.

In the years between 1830 and 1850 at least five other states followed New York and enacted, as companion provisions, (1) a statute declaring feticide to be a crime, punishable as manslaughter, and (2) a statute prohibiting abortion. In California, however, the pattern was not repeated. Much of the Crimes and Punishments Act of 1850 was based on existing New York statute law; but although a section proscribing abortion was included in the new Act (§ 45), the Legislature declined to adopt any provision defining and punishing a special crime of feticide.

(4a) We conclude that in declaring murder to be the unlawful and malicious killing of a "human being" the Legislature of 1850 intended that term to have the settled common law meaning of a person who had been born alive, and did not intend the act of feticide — as distinguished from abortion — to be an offense under the laws of California.

Nothing occurred between the years 1850 and 1872 to suggest that in adopting the new Penal Code on the latter date the Legislature entertained any different intent. The case law of our sister states, for example, remained consonant with the common law. In Abrams v. Foshee (Cole ed. 1856) 3 Iowa 274, 278, the court noted that Iowa's feticide statute (Iowa Rev. Stat. 1843, § 10) had been repealed by the Iowa Code of 1851; it was contended that an unborn child is nevertheless "a human being, within the meaning of [Iowa Code] section 2508, which provides that whoever kills any human being, with malice aforethought, either express or implied, is guilty of murder." The court observed that "notwithstanding the infant in ventre sa mere, is treated by the law for some purposes, as born, or as a human being, yet we are not aware that it has been so treated, so far as to make the act of its miscarriage murder, unless so declared by statute. . . . When the child is born, however, it becomes a human being, within the meaning of the law; and if it shall then die, by reason of any potions or bruises it received in the womb, it would be murder in those who administered or gave them, with a view of causing the miscarriage." ( Ibid.) Citing Blackstone, Coke, and other authorities, the court concluded that "an infant in ventre sa mere, is not a human being within the meaning of" the statute defining murder. ( Id. at p. 279.)

Any lingering doubt on this subject must be laid to rest by a consideration of the legislative history of the Penal Code of 1872. The Act establishing the California Code Commission (Stats. 1870, ch. 516, § 2, p. 774) required the commissioners to revise all statutes then in force, correct errors and omissions, and "recommend all such enactments as shall, in the judgment of the Commission, be necessary to supply the defects of and give completeness to the existing legislation of the State. . . ." In discharging this duty the statutory schemes of our sister states were carefully examined, and we must assume the commissioners had knowledge of the feticide laws noted hereinabove. Yet the commissioners proposed no such law for California, and none has been adopted to this day.

That such an omission was not an oversight clearly appears, moreover, from the commissioners' explanatory notes to Penal Code section 187. After quoting the definitions of murder given by Coke, Blackstone, and Hawkins, the commissioners conclude: "A child within its mother's womb is not a `human being' within the meaning of that term as used in defining murder. The rule is that it must be born. — Rex vs. Brain, 6 Car. P., p. 349. That every part of it must have come from the mother before the killing of it will constitute a felonious homicide. — Rex vs. Brain, 6 Car. P., p. 349; Rex vs. Crutchley, 7 Car. P., p. 814; Rex vs. Sellis, 7 Car. P., p. 850; Rex vs. Poulton, 5 Car. P., p. 329; 2 Bishop's Cr. Law, Secs. 541, 542." (Code Commissioners' Note, Pen. Code of Cal. (1st ed. 1872), p. 81.) The cited cases, of course, are among those we have discussed earlier as representing the settled common law rule that live birth is a prerequisite to a conviction of homicide.

(5) When there is persuasive evidence of a legislative intent contrary to the views expressed in code commissioners' notes, those views will not be followed in construing the statute. (See, e.g., People v. Valentine (1946) 28 Cal.2d 121, 138, 142-144 [ 169 P.2d 1] [contrary to commissioners' note, Legislature omitted important limitation of prior statute in codifying manslaughter provision of Penal Code].) Here, however, the views of the commissioners are in full accord with the history of section 187; and as we have seen, the Legislature made no significant change in that statute when it was codified into the Penal Code. (6) The rule is therefore applicable that "Reports of commissions which have proposed statutes that are subsequently adopted are entitled to substantial weight in construing the statutes. [Citations.] This is particularly true where the statute proposed by the commission is adopted by the Legislature without any change whatsoever and where the commission's comment is brief, because in such a situation there is ordinarily strong reason to believe that the legislators' votes were based in large measure upon the explanation of the commission proposing the bill." ( Van Arsdale v. Hollinger (1968) 68 Cal.2d 245, 249-250 [ 66 Cal.Rptr. 20, 437 P.2d 508].) (7) It is the policy of this state to construe a penal statute as favorably to the defendant as its language and the circumstances of its application may reasonably permit; just as in the case of a question of fact, the defendant is entitled to the benefit of every reasonable doubt as to the true interpretation of words or the construction of language used in a statute. ( Walsh v. Department of Alcoholic Bev. Control (1963) 59 Cal.2d 757, 764-765 [ 31 Cal.Rptr. 297, 382 P.2d 337], and cases cited.) (4b) We hold that in adopting the definition of murder in Penal Code section 187 the Legislature intended to exclude from its reach the act of killing an unborn fetus.

II

(8a) The People urge, however, that the sciences of obstetrics and pediatrics have greatly progressed since 1872, to the point where with proper medical care a normally developed fetus prematurely born at 28 weeks or more has an excellent chance of survival, i.e., is "viable"; that the common law requirement of live birth to prove the fetus had become a "human being" who may be the victim of murder is no longer in accord with scientific fact, since an unborn but viable fetus is now fully capable of independent life; and that one who unlawfully and maliciously terminates such a life should therefore be liable to prosecution for murder under section 187. We may grant the premises of this argument; indeed, we neither deny nor denigrate the vast progress of medicine in the century since the enactment of the Penal Code. But we cannot join in the conclusion sought to be deduced: we cannot hold this petitioner to answer for murder by reason of his alleged act of killing an unborn — even though viable — fetus. To such a charge there are two insuperable obstacles, one "jurisdictional" and the other constitutional.

Penal Code section 6 declares in relevant part that "No act or omission" accomplished after the code has taken effect "is criminal or punishable, except as prescribed or authorized by this code, or by some of the statutes which it specifies as continuing in force and as not affected by its provisions, or by some ordinance, municipal, county, or township regulation. . . ." (9) This section embodies a fundamental principle of our tripartite form of government, i.e., that subject to the constitutional prohibition against cruel and unusual punishment, the power to define crimes and fix penalties is vested exclusively in the legislative branch. ( People v. Knowles (1950) 35 Cal.2d 175, 181 [ 217 P.2d 1]; Harbor Comrs. v. Excelsior Redwood Co. (1891) 88 Cal. 491, 493 [26 P. 375]; People v. Hess (1951) 104 Cal.App.2d 642, 685 [ 234 P.2d 65]; In re Finley (1905) 1 Cal.App. 198, 201 [ 81 P. 1041].) (10) Stated differently, there are no common law crimes in California. ( People v. Redmond (1966) 246 Cal.App.2d 852, 862, [ 55 Cal.Rptr. 195]; People v. Harris (1961) 191 Cal.App.2d 754, 758 [ 12 Cal.Rptr. 916]; In re Harder (1935) 9 Cal.App.2d 153, 155 [ 49 P.2d 304].) "In this state the common law is of no effect so far as the specification of what acts or conduct shall constitute a crime is concerned. [Citations.] (11) In order that a public offense be committed, some statute, ordinance or regulation prior in time to the commission of the act, must denounce it; likewise with excuses or justifications — if no statutory excuse or justification apply as to the commission of the particular offense, neither the common law nor the so-called `unwritten law' may legally supply it." ( People v. Whipple (1929) 100 Cal.App. 261, 262 [ 279 P. 1008].)

Settled rules of construction implement this principle. (12) Although the Penal Code commands us to construe its provisions "according to the fair import of their terms, with a view to effect its objects and to promote justice" (Pen. Code, § 4), it is clear the courts cannot go so far as to create an offense by enlarging a statute, by inserting or deleting words, or by giving the terms used false or unusual meanings. ( People v. Baker (1968) 69 Cal.2d 44, 50 [ 69 Cal.Rptr. 595, 442 P.2d 675].) Penal statutes will not be made to reach beyond their plain intent; they include only those offenses coming clearly within the import of their language. ( De Mille v. American Fed. of Radio Artists (1947) 31 Cal.2d 139, 156 [ 187 P.2d 769, 175 A.L.R. 382].) Indeed, "Constructive crimes — crimes built up by courts with the aid of inference, implication, and strained interpretation — are repugnant to the spirit and letter of English and American criminal law." ( Ex parte McNulty (1888) 77 Cal. 164, 168 [19 P. 237].)

(8b) Applying these rules to the case at bar, we would undoubtedly act in excess of the judicial power if we were to adopt the People's proposed construction of section 187. As we have shown, the Legislature has defined the crime of murder in California to apply only to the unlawful and malicious killing of one who has been born alive. We recognize that the killing of an unborn but viable fetus may be deemed by some to be an offense of similar nature and gravity; but as Chief Justice Marshall warned long ago, "It would be dangerous, indeed, to carry the principle, that a case which is within the reason or mischief of a statute, is within its provisions, so far as to punish a crime not enumerated in the statute, because it is of equal atrocity, or of kindred character, with those which are enumerated." ( United States v. Wiltberger (1820) 18 U.S. (5 Wheat.) 76, 96 [5 L.Ed. 37, 42].) Whether to thus extend liability for murder in California is a determination solely within the province of the Legislature. For a court to simply declare, by judicial fiat, that the time has now come to prosecute under section 187 one who kills an unborn but viable fetus would indeed be to rewrite the statute under the guise of construing it. Nor does a need to fill an asserted "gap" in the law between abortion and homicide — as will appear, no such gap in fact exists — justfy judicial legislation of this nature: to make it "a judicial function `to explore such new fields of crime as they may appear from time to time' is wholly foreign to the American concept of criminal justice" and "raises very serious questions concerning the principle of separation of powers." ( In re Davis (1966) 242 Cal.App.2d 645, 655-656 fn. 12 [ 51 Cal.Rptr. 702].)

The second obstacle to the proposed judicial enlargement of section 187 is the guarantee of due process of law. Assuming arguendo that we have the power to adopt the new construction of this statute as the law of California, such a ruling, by constitutional command, could operate only prospectively, and thus could not in any event reach the conduct of petitioner on February 23, 1969.

(13) The first essential of due process is fair warning of the act which is made punishable as a crime. "That the terms of a penal statute creating a new offense must be sufficiently explicit to inform those who are subject to it what conduct on their part will render them liable to its penalties, is a well-recognized requirement, consonant alike with ordinary notions of fair play and the settled rules of law." ( Connally v. General Constr. Co. (1926) 269 U.S. 385, 391 [70 L.Ed. 322, 328, 46 S.Ct. 126].) "No one may be required at peril of life, liberty or property to speculate as to the meaning of penal statutes. All are entitled to be informed as to what the State commands or forbids." ( Lanzetta v. New Jersey (1939) 306 U.S. 451, 453 [83 L.Ed. 888, 890, 59 S.Ct. 618].) The law of California is in full accord. ( In re Newbern, supra, 53 Cal.2d 786, 792; In re Davis, supra, 242 Cal.App.2d 645, 650-651.)

(14) This requirement of fair warning is reflected in the constitutional prohibition against the enactment of ex post facto laws (U.S. Const., art. I, §§ 9, 10; Cal. Const., art. I, § 16). When a new penal statute is applied retrospectively to make punishable an act which was not criminal at the time it was performed, the defendant has been given no advance notice consistent with due process. And precisely the same effect occurs when such an act is made punishable under a preexisting statute but by means of an unforeseeable judicial enlargement thereof. ( Bouie v. City of Columbia (1964) 378 U.S. 347 [12 L.Ed.2d 894, 84 S.Ct. 1697].)

In Bouie two Negroes took seats in the restaurant section of a South Carolina drugstore; no notices were posted restricting the area to whites only. When the defendants refused to leave upon demand, they were arrested and convicted of violating a criminal trespass statute which prohibited entry on the property of another "after notice" forbidding such conduct. Prior South Carolina decisions had emphasized the necessity of proving such notice to support a conviction under the statute. The South Carolina Supreme Court nevertheless affirmed the convictions, construing the statute to prohibit not only the act of entering after notice not to do so but also the wholly different act of remaining on the property after receiving notice to leave.

The United States Supreme Court reversed the convictions, holding that the South Carolina court's ruling was "unforeseeable" and when an "unforeseeable state-court construction of a criminal statute is applied retroactively to subject a person to criminal liability for past conduct, the effect is to deprive him of due process of law in the sense of fair warning that his contemplated conduct constitutes a crime." (378 U.S. at pp. 354-355 [12 L.Ed.2d at p. 900].) Analogizing to the prohibition against retrospective penal legislation, the high court reasoned "Indeed, an unforeseeable judicial enlargement of a criminal statute, applied retroactively, operates precisely like an ex post facto law, such as Art. I, § 10, of the Constitution forbids. An ex post facto law has been defined by this Court as one `that makes an action done before the passing of the law, and which was innocent when done, criminal; and punishes such action,' or `that aggravates a crime, or makes it greater than it was, when committed.' Calder v. Bull, 3 Dall. 386, 390, 1 L.Ed. 648, 650. If a state legislature is barred by the Ex Post Facto Clause from passing such a law, it must follow that a State Supreme Court is barred by the Due Process Clause from achieving precisely the same result by judicial construction. Cf. Smith v. Cahoon, 283 U.S. 553, 565, 75 L.Ed. 1264, 1273, 51 S.Ct. 582. The fundamental principle that `the required criminal law must have existed when the conduct in issue occurred,' Hall, General Principles of Criminal Law (2d ed. 1960), at 58-59, must apply to bar retroactive criminal prohibitions emanating from courts as well as from legislatures. If a judicial construction of a criminal statute is `unexpected and indefensible by reference to the law which had been expressed prior to the conduct in issue,' it must not be given retroactive effect. Id., at 61." (Fn. omitted.) ( Id. at pp. 353-354 [12 L.Ed.2d at pp. 899-900].)

The court remarked in conclusion that "Application of this rule is particularly compelling where, as here, the petitioners' conduct cannot be deemed improper or immoral." ( Id. at p. 362 [12 L.Ed.2d at p. 905].) In the case at bar the conduct with which petitioner is charged is certainly "improper" and "immoral," and it is not contended he was exercising a constitutionally favored right. (15) But the matter is simply one of degree, and it cannot be denied that the guarantee of due process extends to violent as well as peaceful men. The issue remains, would the judicial enlargement of section 187 now proposed have been foreseeable to this petitioner?

It is true that section 187, on its face, is not as "narrow and precise" as the South Carolina statute involved in Bouie; on the other hand, neither is it as vague as the statutes struck down in Connally and Lanzetta. Rather, section 187 bears a plain, common sense meaning, well settled in the common law and fortified by its legislative history in California. In Bouie, moreover, the court stressed that a breach of the peace statute was also in force in South Carolina at the time of the events, and that the defendants were in fact arrested on that ground and prosecuted (but not convicted) for that offense. (16a) Here, too, there was another statute on the books which petitioner could well have believed he was violating: Penal Code section 274 defines the crime of abortion, in relevant part, as the act of "Every person who . . . uses or employs any instrument or any other means whatever, with intent thereby to procure the miscarriage" of any woman, and does not come within the exceptions provided by law. (17) The gist of the crime is the performance, with the requisite intent, of any of the acts enumerated in the statute. ( People v. Root (1966) 246 Cal.App.2d 600, 604 [ 55 Cal.Rptr. 89]; People v. Moore (1963) 213 Cal.App.2d 160, 167 [ 23 Cal.Rptr. 502].) It is therefore no defense to a charge of violating section 274 that the act was committed unusually late in the woman's pregnancy or by a method not commonly employed for that purpose. The prohibition is against "any means which might be used to effect a miscarriage" ( People v. Clapp (1944) 67 Cal.App.2d 197, 202 [ 153 P.2d 758]), and has been applied to instances of beating or other physical violence inflicted upon the person of the woman for this purpose. (16b) In the present case, it will be remembered, petitioner's avowed goal was not primarily to kill the fetus while it was inside his wife's body, but rather to "stomp it out of" her; although one presumably cannot be done without the other, petitioner's choice of words is significant and strongly implies an "intent thereby to procure the miscarriage" of his wife in violation of section 274.

Turning to the case law, we find no reported decision of the California courts which should have given petitioner notice that the killing of an unborn but viable fetus was prohibited by section 187. Indeed, the contrary clearly appears from People v. Eldridge (1906) 3 Cal.App. 648, 649 [ 86 P. 832], in which the defendant challenged as uncertain an information which charged him with the murder of "a human being," to wit, the infant child "born to the said Glover H. Eldridge and said Mabel Eldridge on or about said twentieth day of February, 1905." It was urged that "such charge might include the killing before birth, and therefore it cannot be determined from the information whether murder or abortion was intended to be charged." The Court of Appeal rejected the contention, observing that "The only reasonable construction which can be given to the language employed in the information is to say that it charges that a child born to the defendant was by him unlawfully killed and murdered. That it was born is clearly stated; that it could be killed after birth of necessity implies that it was born alive, and we think the charge of murder was set forth with the degree of certainty required." (Italics added.)

Properly understood, the often cited case of People v. Chavez (1947) 77 Cal.App.2d 621 [ 176 P.2d 92], does not derogate from this rule. There the defendant was charged with the murder of her newborn child, and convicted of manslaughter. She testified that the baby dropped from her womb into the toilet bowl; that she picked it up two or three minutes later, and cut but did not tie the umbilical cord; that the baby was limp and made no cry; and that after 15 minutes she wrapped it in a newspaper and concealed it, where it was found dead the next day. The autopsy surgeon testified that the baby was a full-term, nine-month child, weighing six and one-half pounds and appearing normal in every respect; that the body had very little blood in it, indicating the child had bled to death through the untied umbilical cord; that such a process would have taken about an hour; and that in his opinion "the child was born alive, based on conditions he found and the fact that the lungs contained air and the blood was extravasated or pushed back into the tissues, indicating heart action." ( Id. at p. 623.)

On appeal, the defendant emphasized that a doctor called by the defense had suggested other tests which the autopsy surgeon could have performed to determine the matter of live birth; on this basis, it was contended that the question of whether the infant was born alive "rests entirely on pure speculation." ( Id. at p. 624.) The Court of Appeal found only an insignificant conflict in that regard ( id. at p. 627), and focussed its attention instead on testimony of the autopsy surgeon admitting the possibility that the evidence of heart and lung action could have resulted from the child's breathing "after presentation of the head but before the birth was completed" ( id. at p. 624).

The court cited the mid-19th century English infanticide cases mentioned hereinabove, and noted that the decisions had not reached uniformity on whether breathing, heart action, severance of the umbilical cord, or some combination of these or other factors established the status of "human being" for the purposes of the law of homicide. ( Id. at pp. 624-625.) The court then adverted to the state of modern medical knowledge, discussed the phenomenon of viability, and held that "a viable child in the process of being born is a human being within the meeting of the homicide statutes, whether or not the process has been fully completed. It should at least be considered a human being where it is a living baby and where in the natural course of events a birth which is already started would naturally be successfully completed." (Italics added.) ( Id. at p. 626.) Since the testimony of the autopsy surgeon left no doubt in that case that a live birth had at least begun, the court found "the evidence is sufficient here to support the implied finding of the jury that this child was born alive and became a human being within the meaning of the homicide statutes." (Italics added.) ( Id. at p. 627.) (18) Chavez thus stands for the proposition — to which we adhere — that a viable fetus "in the process of being born" is a human being within the meaning of the homicide statutes. But it stands for no more; in particular it does not hold that a fetus, however viable, which is not "in the process of being born" is nevertheless a "human being" in the law of homicide. On the contrary, the opinion is replete with references to the common law requirement that the child be "born alive," however that term as defined, and must accordingly be deemed to reaffirm that requirement as part of the law of California.

The Chavez court relied in part on Scott v. McPheeters (1939) 33 Cal.App.2d 629 [ 92 P.2d 678, 93 P.2d 562], a decision holding that an unborn child is an "existing person," within the meaning of Civil Code section 29, for the purpose of bringing a postnatal action for prenatal injuries. In People v. Belous, supra, 71 Cal.2d 954, however, a majority of this court distinguished such civil law rules on the ground they either "require a live birth or reflect the interest of the parents." ( Id. at p. 968 fn. 12.) We need not repeat that analysis here; but two further bases of distinction deserve mention. First, Scott emphasized that the child's right of action for prenatal injuries was unknown to the common law and would not exist in California but for statutory authorization. By the same token, as we have seen, the fetus' status as a "human being" within the definition of murder was unknown to the common law and exists only where special feticide statutes have been enacted. Secondly, the law's protection of the property interests of an unborn child dates not from Scott but from a far earlier time: for example, in Blackstone's day it was already well settled that "An infant in ventre sa mere, or in the mother's womb, is supposed in law to be born for many purposes. It is capable of having a guardian assigned to it; and it is enabled to have an estate limited to its use, and to take afterwards by such limitation, as if it were then actually born." (1 Blackstone, Commentaries 130 (1765).) Inasmuch as such rules coexisted for centuries with the common law requirement of live birth to support a conviction of homicide, they cannot reasonably be deemed to have given petitioner notice that the killing of an unborn but viable fetus would now be murder.

Finally, although a defendant is not bound to know the decisional law of other states, the United States Supreme Court in Bouie (378 U.S. at pp. 360-361 [12 L.Ed.2d at pp. 903-904]) referred to reported cases of jurisdictions other than South Carolina in concluding that the South Carolina Supreme Court's construction of the statute "is no less inconsistent with the law of other States than it is with the prior case law of South Carolina and, of course, with the language of the statute itself." Here, too, the cases decided in our sister states from Chavez to the present are unanimous in requiring proof that the child was born alive before a charge of homicide can be sustained. ( Bennett v. State (Wyo. 1963) 377 P.2d 634, 635-637; People v. Ryan (1956) 91 Ill.2d 467 [ 138 N.E.2d 516, 518-520]; People v. Hayner (1949) 300 N.Y. 171 [ 90 N.E.2d 23, 24]; Singleton v. State (1948) 33 Ala. App. 536 [ 35 So.2d 375, 378]; Montgomery v. State (1947) 202 Ga. 678 [ 44 S.E.2d 242, 243-244]; cf. Watson v. State (1955) 208 Md. 210 [ 117 A.2d 549, 552].) And the text writers of the same period are no less unanimous on the point. (Perkins on Criminal Law, supra, pp. 29-30; Clark Marshall, Crimes (6th ed. 1958) § 10.00, pp. 534-536; 1 Wharton, Criminal Law and Procedure (Anderson ed. 1957) § 189; 2 Burdick, Law of Crime (1946) § 445; 40 Am.Jur.2d, Homicide, §§ 9, 434; 40 C.J.S., Homicide, § 2b.)

(8c) We conclude that the judicial enlargement of section 187 now urged upon us by the People would not have been forseeable to this petitioner, and hence that its adoption at this time would deny him due process of law.

Let a peremptory writ of prohibition issue restraining respondent court from taking any further proceedings on Count I of the information, charging petitioner with the crime of murder.

McComb, J., Peters, J., Tobriner, J., and Peek, J.,^fn_ concurred.