The two subsections of section 731 describe situations which are generally mutually exclusive, so, although aspects of both subsections may be applicable in a particular case, the subsections are presented as separate instructions for purposes of clarity. The instructions follow the language of the statute, with only minor modifications used in the interest of clarity, to enable the trial judge to select those circumstances descriptive of the case on trial.

The law in Oklahoma regarding excusable homicide is well settled. Excusable homicide is distinguished from killings termed justifiable homicide in that the latter involves the taking of life as a matter of right, such as self-defense or other statutorily defined cause, as set forth in section 733 of Title 21. However, "excusable homicide is where death results from a lawful act by lawful means, accomplished accidentally or by misfortune or misadventure, or accomplished with sufficient provocation, with no undue advantage and without unnecessary cruel treatment." Gaunce v. State, 22 Okl. Cr. 361, 364, 211 P. 517, 518 (1923).

The court has termed "misfortune" analogous to "misadventure," so that in a homicide situation "misfortune" means that, without unlawful intent, the lawful conduct of a person unfortunately causes the death of another. Adams v. State, 93 Okl. Cr. 333, 228 P.2d 195 (1951); Mead v. State, 65 Okl. Cr. 86, 83 P.2d 404 (1938); Gaunce, supra.

That excusable homicide becomes an issue for jury consideration only where death results from conduct that is otherwise lawful is reiterated throughout the cases. In Johnson v. State, 506 P.2d 963 (Okl. Cr. 1973), the defendant urged as error on appeal from his conviction for manslaughter in the first degree the trial court's refusal to instruct the jury concerning excusable homicide. The defendant had carried a firearm in his belt throughout the entire evening on which the homicide occurred. The defendant maintained during his trial that the deceased had provoked an altercation with him and that during the ensuing struggle, the gun accidentally discharged, causing her death. In affirming the conviction, the court observed that section 1272 of Title 21 prohibits the carrying of a firearm, and declared:

Id. at 967. Accord, Rice v. State, 567 P.2d 525 (Okl. Cr. 1977) (defendant shot at deceased with shotgun through open window); Bell v. State, 381 P.2d 167 (Okl. Cr. 1963) (defense of excusable homicide not available to defendant who committed homicide while attempting to escape in a stolen car, and while shooting at pursuing police officers). See also Seals v. State, 92 Okl. Cr. 272, 222 P.2d 1037 (1950) (defendant's conviction for first-degree manslaughter for homicide resulting from defendant's disciplining of his stepson affirmed where evidence showed defendant had subjected the child to protracted and continuous abuse, culminating in final, fatal blow).

By contrast, the court reversed a conviction for first-degree manslaughter in Thompson v. State, 507 P.2d 1271 (Okl. Cr. 1973), where the trial judge refused to instruct on excusable homicide, and instead instructed the jurors concerning justifiable homicide. The defendant testified that she and her adopted son were scuffling over a rifle, which was not pointed at the deceased, but accidentally discharged, killing him. The defendant maintained she did not know what caused the rifle to discharge, whether she or her son had inflicted the fatal wound, or whether it was caused by a shot from a rifle which the deceased was firing. Under these circumstances, refusal to instruct regarding the defendant's theory of excusable homicide constituted reversible error. Accord Dennis v. State, 556 P.2d 617 (Okl. Cr. 1976) (error to refuse to instruct on excusable homicide where defendant's evidence showed homicide could have occurred as a result of a hunting accident).

Defense by the defendant against an unprovoked assault by the deceased has been held to warrant an instruction on excusable homicide, as long as the remaining statutory requirements are met. For example, in Mead v. State, supra, the deceased approached the defendant, shouted abusive words at him, and shoved his hand at the defendant's face. The defendant struck the deceased, who fell into a ditch and expired. The death was caused by a blood clot or embolism in the left pulmonary artery. In reversing a conviction for manslaughter in the second degree, the court observed:

65 Okl. Cr. at 98, 83 P.2d at 410. See also Adams v. State, 93 Okl. Cr. 333, 228 P.2d 195 (1951); Palmer v. State, 78 Okl. Cr. 220, 146 P.2d 592 (1944); Johnson v. State, 59 Okl. Cr. 283, 58 P.2d 156 (1936).