But it may be objected that no evil act may be done to procure a good result, that a good end does not justify a bad means. That is a correct principle, and we will consider it carefully some other day. But my act of necessary self-defence is not evil, and therefore needs no justification; for the means I employ are, under the circumstances, well-ordered and lawful means, which violate no one's rights, as has just been shown. Of course the harm I do to the aggressor is just only in as far as it is strictly necessary to defend the inalienable right I have to life or limb or very valuable property. Hence I must keep within the just limits of self-defence. To shoot an assailant, when I am in no serious danger, or when I can free myself some other way, or when I act through malice, would not be self-defence, but unjustifiable violence on my part. 2. The principles that make it lawful for a man to defend his own life with violence against an unjust assailant will also justify a parent in thus defending his children, a guardian his wards; and in fact any one may forcibly defend any other human being against unjust violence. A parent or guardian not only can, but he is in duty bound to, defend those under his charge by all lawful means. Similarly the physician would be obliged to defend his patient by the exercise of his profession in his behalf. Now the only case in which the need of medical treatment against unjust aggression could become a matter for discussion in Jurisprudence is the case of a mother with child. Is the child under those circumstances really an unjust aggressor? Let us study that important case with the closest attention. Let all the rays of light we have gathered so far be focussed on this particular point. Can a physician ever be justified in destroying the life of a child, before or during its birth, by craniotomy or in any other manner, in order to save its mother's life, on the plea that the child is an unjust assailant of the life of its mother? Put the case in a definite shape before you. Here is a mother in the pangs of parturition. An organic defect, no matter in what shape or form, prevents deliverance by the ordinary channels. All that medical skill can do to assist nature has been done. The case is desperate. Other physicians have been called in for consultation, as the civil law requires before it will tolerate extreme measures. All agree that, if no surgical operation is performed, both mother and child must die. There are the Cæsarian section, the Porro operation, laparotomy, symphysiotomy, all approved by science and the moral law. But we will suppose an extreme case; namely, the circumstances are so unfavorable for any of these operations--whether owing to want of skill in the Doctors present, or for any other reason--that none can safely be attempted; any of them would be fatal to the mother.