"The law throws on the prisoner the _onus_ of proving that, at the time the offence was committed, he was in an unsound state of mind; and you will have to say, after hearing my explanation of the law, whether this has been made out to your satisfaction. In the first place, you must clearly understand that it is not because a man is insane that he is unpunishable: and I must say, that _upon this point there exists a very grievous delusion in the minds of medical men_. The only insanity which excuses a man for his acts is that species of delusion which conduced to, and drove him to commit, _the act alleged against him_. If, for instance, a man, being under the delusion that another man would kill him, killed that other, for, as he supposed, his own protection, he would be unpunishable for such an act; because it would appear that the act was done under the delusion that he could not protect himself in any other manner: and there the particular description of insanity conduced to the offence. But, on the other hand, if a man has a delusion that his head is made of glass, that will be no excuse for his killing a man. He would know very well that, although his head were made of glass, that was no reason why he should kill another man, and that it was a wrong act; and he would be properly subjected to punishment for that act. These are the principles which ought to govern the decision of juries in such cases. They ought to have clear proof of a formed disease of the mind--a disease existing before the act was committed, and which made the person accused incapable of knowing, at the time he did the act, that it was a wrong act for him to do. This is the rule which I shall direct you to be governed by. Try the case by this test. Did this unfortunate gentleman know, at the time, that it was wrong to strike the Queen on the forehead? Now, there is no doubt that he was very eccentric in his conduct; but did that eccentricity disable him from judging whether it was right or wrong to strike the Queen? Is _eccentricity_ to excuse a man for any crime he may afterwards commit? The prisoner is proved to have been perfectly well aware of what he had done immediately afterwards, and in the interview which he had had since with one of the medical gentlemen, he admitted that he knew perfectly well what he had done, and ascribed his conduct to some momentary uncontrollable impulse. The law does not acknowledge such an impulse, if the person was aware that it was a wrong act he was about to commit; and he is answerable for the consequences. A man might say that he picked a pocket from some uncontrollable impulse; and in that case, the law would have an uncontrollable impulse to punish him for it. What evidence is there, then, in this case to justify you in coming to the conclusion, that when the prisoner struck the Queen he did not know