Homicide , in criminal law, the killing of one human being by another. By the common law, it is not homicide to kill an infant before its birth, the authorities declaring that if one purposely kills a babe not yet born, it is only a misdemeanor and not a felony; but if the child is born alive and then dies from the previous injury, it is felony. So, if one intending to procure abortion does an act which causes a child to be born prematurely, and being so born, it dies because not mature enough to live, this is murder. But where a woman cut off the head of her child before it was wholly born, it was held not to be murder. The crime of child murder and wilful abortion is made punishable in many of our states by statute. Homicide is divided into three classes, justifiable, excusable, and felonious. Felonious homicide is either manslaughter or murder, which will be treated under those titles. In this article we shall speak only of homicide which is justifiable, and that which is excusable. These two are often confounded, and are sometimes spoken of as if they were the same thing, even in technical books of criminal law. But this is an inaccuracy.

Justifiable homicide is that which is just and right, and not to be regretted; while excusable homicide is that for which excuses may be offered which take away wilful guilt from the killer, however much the act may be lamented. In this strict sense, there is perhaps no justifiable homicide except that which is committed officially and in the discharge of a legal duty; that is, there is no homicide strictly justifiable except the homicide by an executioner, or that of a public enemy in open war. If one, at great risk to himself, and in defence of the innocent, encounters and destroys an assassin, who could not otherwise be prevented from putting many to death and in-flicting injuries worse than death, he may deserve and receive general applause. And the excuse extends much beyond those crimes which are punishable with death; because a man would be excused for putting an offender to death if that were the only way of preventing certain crimes which if committed might not be punished with death, such as rape, burglary with arms, or robbery with arms.

Again, the excuse in this case, as in that of self-defence, does not depend altogether upon the actual facts of the case, but much, and perhaps principally, upon the appearance of it to the person committing the homicide; for if, as a reasonable man, he was fully justified in believing that the peril from which he could deliver himself only by homicide was actual and imminent, the excuse is not taken away by proof that he was deceived. Thus, if one were attacked by an assailant threatening to shoot him with a pistol, and would be justified under the circumstances in killing his assailant if the pistol were loaded and the assailant intended to use it, and the assailed party had reason to believe this to be the case, his excuse would not be lessened by proof that the pistol was not loaded and his death not intended. The excuses for homicide sometimes mingle; thus one who is attacked by a murderer and cannot otherwise escape, may put him to death, either to prevent this felony, or to save his own life.

But one who would escape the consequences of homicide by the excuse of self-defence, must be able to show that there was some overt act on the part of the assailant, and that the assailed was not moved by threats only, or merely by fears of what would be done, however just and rational they might be; but waited until some act took place to protect himself, not merely from fatal violence, but from grievous bodily injury. What this means is not plainly defined by the law; but it does not mean the injury caused by a blow from a fist or a stick, or a slight wound, which might be painful for a time, but from all effects of which the injured person would certainly and entirely recover within a few days. And here, too, as before, death must not be inflicted until nothing but this remains. That is, the party assailed must retreat as long and as far as he can retreat; must seek and use any refuge or means of escape open to him; and only when these are exhausted, or non-existent, can he put his assailant to death. It should however be stated, as a settled rule of law, that an assailed party, in danger of death or grievous harm, is bound to retreat only when he can do this with safety.

For if retreat will only increase a danger already imminent, and give his assailant new power over him, he need not retreat at all, but may at once inflict death upon his assailant. So, too, homicide is excusable if inflicted as the only means of preventing a great crime. Here the law comes in with what may seem to be a definition; for it says that one may inflict death if there be no other way to prevent a felony. But the reader will see, under the title Felony, that its meaning is quite undetermined; and there are things which are still called felonies, at least in England, of which we should be unwilling to say that they might lawfully be prevented by putting the offender to death. And yet it must be certain that the law would call this only excusable homicide, and not justifiable. Excusable homicide is then that which is caused by self-defence, or the prevention of great crime, or accident. It is excusable by reason of self-defence, if it was strictly necessary for this purpose, and not otherwise. We believe that there is no rule of criminal law which ought to be more certain, and more universally acknowledged, than that homicide in self-defence must be grounded upon a strict and absolute necessity.

It cannot be doubted that any one may save his own life by taking the life of his assailant; but it is equally certain, as matter of law, that he must not secure his safety by homicide provided he could secure it in any other way, as by retreating, or seeking refuge, or inflicting a less than fatal injury. We suppose that any difficulty which belongs to this subject must attend upon the application of these principles, and not upon the principles themselves. Thus, it is certain that the laws of England and of the United States agree in an absolute refusal to recognize the point of honor in cases of homicide. Juries, and possibly courts, may be influenced by it, perhaps unconsciously; but the law ignores it. If one attacks another with every form and method of insult, and the attacked party, finding no other way of stopping the insult, or escaping from it, puts the assailant to death, it is felonious and not excusable homicide. In reference to the excuse of accident also, it may be mingled with another.

Thus, while one has no right to protect himself from slight bodily injury by putting his assailant to death, or to use that means of preventing wrongful conduct not of the gravest sort, yet he has a right to defend himself against any assault, and to protect himself from any injury, and to prevent any wrong doing. And if in all this he uses no weapons likely to produce death, and does not manifest by violence and excess a fatal purpose, he would be excused although the death of the wrong doer was the unintended result. Thus, one may turn a mere intruder out of his house, although he is quiet there, and, if necessary, put him out by force; but must not put him to death because he will not go out. But if, while using only such force as may seem necessary, he kills the intruder, he would be excused. In reference to this right of self-protection, the question has been raised whether the use of spring guns is lawful. It seems to be the law that one may use a spring gun to prevent felony, and that homicide caused by it would be excusable; but that it is not justifiable to use such instruments for protection against mere trespassers.