delivered the opinion of the Court.
The plaintiff in error was convicted in the Cook Circuit Court, on an indictment for the murder of his wife. He brings the record here, complaining of several errors alleged to have been committed to his prejudice, the most important of which, we propose to notice.
He complains,- first, that the Circuit Court would not permit him to. give evidence of his uniform good character as a man and a citizen.
It was, at onetime, a disputed question, whether such evidence could be given in a case where, as in this, the homicide is not denied. Some of the books say, such evidence, if offered, ought to be restricted to the trait of character in issue, or, in other words, should bear some analogy to the nature of the charge. 3 Gr. Ev., sec. 25.
To the same effect is 2 Euss. on Crimes, 784, but yet, he says, the good character of an accused party is an ingredient which should always be submitted to the consideration of the jury, along with the other facts of the case. Ib. 785.
In a case where the defense is insanity, we cannot have a doubt, that evidence of uniform good character as a man and a citizen, is proper for the jury to consider; whether a person whose character has been uniformly good, has, in a sane moment, committed the crime charged. It is undoubtedly true, a sane man, whose previous character has been unexceptionable, may commit an atrocious homicide, no doubt may exist of the fact, yet, under his plea of insanity, should he not be entitled to all the benefit which may be derived *388from the fact of uniform good character, as tending, slightly, it may be, to the conclusion that he could not have been sane at the time the deed was done. Generally, a person of good character does not, of a sudden, fall from a high position, to the commission of outrageous crimes ; should he do so, would it be an unnatural or forced inference, that he may have been affected with insanity at the time % But be this as it may, it seems to be now settled, that such evidence in capital cases, is admissible. In the case of the Commonwealth v. Hardy, 2 Mass. 317, which was a capital case, ParsoNS, Oh. J., said, a prisoner ought to be permitted to give in evidence his general character in all cases. Sewell and Parxer, justices, said, they were not prepared to admit that testimony of general character should be admitted in behalf of the defendant, in all criminal prosecutions; but, they were clearly of opinion, that it might be admitted in capital cases in favor of life. The same rule was stated in the case of the Commonwealth v. Webster, 5 Cushing, 325. The court there say, it is the privilege of the accused, to put his character in issue or not.
In 2 Bennet and Heard’s Leading Cases, 159, and notes, the cases are collected and commented on, in which this rule is recognized.
In the case of The People v. Vane, 12 Wendell, 78, the court held, that evidence of the good character of the defendant on the trial of an indictment, is always admissible, though it cannot avail when the evidence against him is positive and unimpeached; but when the evidence is circumstantial, or comes from a suspected or impeached witness, proof of good character is important.
We think, at least in view of the defense relied on, the evidence of the prisoner’s uniform correct bearing, as a man and a citizen, should have been made known to the jury. A good character is a most precious possession,' and it ought to be permitted, in favor of life at least, to go to the jury.
The plaintiff in error also complains, that the prosecution was permitted to prove that about thirty years before the commission of the crime charged, he had been engaged in a violation of the revenue laws of the country, by a career of smuggling *389goods and property, to and from Canada. The prisoner insists it was not competent to prove this offense against him; that all the facts proper to be proved, should be strictly relevant to the particular charge, and have no reference to any of his conduct, not connected with the charge.
This is undoubtedly true as a general principle, but we think such proof was warranted in this view. The defense being insanity, the coolness and unconcern of the prisoner at the time he did the fatal act, was made a prominent feature in the case, and inferences were sought to be drawn from it, favorable to the plea.
Is it possible, ask his counsel, that a man who could show so much coolness, self-possession and apathy, at the moment and after the fatal deed, could be otherwise than insane ? To this the people reply, the prisoner had spent years of his early life in a perilous calling, demanding, at all times, great coolness and hardihood, and. therein, had educated his nerves to withstand any shock; in such a school he learned the deportment exhibited by him on the fatal occasion. To account for this coolness and unconcern, the testimony of Beardsley and Phelps was properly received, it being in the nature of rebutting evidence on the point made.
But these are small points, compared to those we must consider.
The prisoner complains, that the court did not lay down to the jury, correctly, the law of his case. That he was prejudiced by the charge of the court, not coming up, as he alleges it should have done, to the true principles involved in it, by which guilt was established in a case where guilt could not exist, and for which his life must be forfeited, if this court has no corrective power.
The homicide stands confessed. It has never been denied by the prisoner; on the contrary, he declared on its commission, that it had been long contemplated and was right; that his wife was unchaste. After his arrest, he justified the deed, and has, throughout, exhibited total indifference and unconcern.
His counsel say for him, he was not of sound mind when *390the deed was done, and tbe court, trying the cause, gave to the jury, at great length, its views of the nature of the defense, and prescribed the rule which should govern them, in the decision of the case.
We do not propose to examine, in detail, the several instructions given by the court for the prosecution, or those refused when asked by. the defense. We are not fully convinced what the rule, or tests, should be in such cases. The results of scientific investigation oh this intricate subject, are so imperfect as to render it very difficult to establish any general rule, by which judicial proceedings of a criminal nature should be governed, when the defense of insanity is interposed. Writers on the subject treat of several different kinds of insanity, and of different degrees of the several kinds, and among them, there is considerable diversity of opinion on the same point. They furnish, as yet, no true and safe guide for courts and juries, but it is hoped as science advances, a rule will be eliminated, which, whilst it shall throw around these poor unfortunates a sufficient shield, shall, at the same time, place no great interest of community in jeopardy.
It is now generally conceded, that insanity is a disease of the brain, of that mass of matter through and by which that mysterious power, the mind, acts. There, the mind is supposed to be enthroned, acting through separate and distinct organs. These organs may become diseased, one or more or all, and in the degree, or to the extent of such disease, is insanity measured. A disease of all the organs, causes total insanity, while of one or more, partial insanity only. There is, it seems, a general intellectual mania, and a partial intellectual mania, and a moral mania, which is also divided into general and partial. It is claimed for the prisoner, that the species of insanity with which he is afflicted, is of the partial intellectual order, denominated monomania; that is to say, a mania on one snbject, and that subject, the infidelity of his wife, in which his belief, without the least ground to base it upon, was so fixed as to become a deep-seated delusion amounting to mania. In the simplest form of this species of mania, the understanding appears to be tolerably sound on all subjects *391but those connected with the hallucination. Raj’s Med. Jur. 164.
Premising these, it is truly said, it has been found difficult to establish any general rule under which all these varieties of insanity may be safely included and controlled, when such a defense is made.
The rule prevailing in the times of Lord Coxe, Hale, and other luminaries of the law, in its not most enlightened days, was, that to exempt from punishment, the party charged must be totally deprived of his understanding and memory. As science advanced, and closer investigations were had upon this subject, it was held, if the accused had so far lost the use of his understanding as not to know right from wrong, he was not responsible, and this rule has been so far modified as to be applied to the precise act for which the prisoner may be indicted.
This rule seems to have been adhered to by the English courts, and by some of the courts of this country, with occasional departures only, as in Hadfield’s case, and other cases commented upon in notes to 1 Leading Criminal Cases, 93. In Hadfield’s case, tried before Lord KeNyoN, in 1800, it was held, if the accused was laboring under a sincere and firm delusion, that it was his duty to do the act charged, and it was done under the influence of such delusion, he was not responsible. Yet in Dillingham’s case, tried before Sir James MaNseield, in 1812, reported in 5 Carr. & Payne, 169, the old rule of Lord Hale’s time, was announced and enforced, and an undoubted lunatic condemned to the gallows.
We do not propose to go into an examination of the various decisions, English and American, on this subject, it being sufficient to say, that no certain, uniform and definite .rule, can be gathered from them. In the midst of this uncertainty, with the best reflection and examination we have been able to give to this very important and most interesting question, we have come to the conclusion, that a safe and reasonable test, in all such cases, would be, that whenever it should appear from the evidence, that at the time of doing the act charged, the prisoner was not of sound mind, but affected *392with insanity, and sucb affection was the efficient cause of the act, and that he would not have done the act but for that affection, he ought to be acquitted. But this unsoundness of mind, or affection of insanity, must be of such a degree as to create an uncontrollable impulse to do the act charged, by overriding the reason and judgment, and obliterating the sense of right and wrong as to the particular act done, and depriving the accused of the power of choosing between them. If it be shown the act was the consequence of an insane delusion, and caused by it, and by'nothing else, justice and humanity alike demand an acquittal. Our statute was designed to ameliorate the rigor of the old rule of the common law, in declaring that a person “ affected with insanity,” shall not be considered a fit subject of punishment, for an act done, which, under other circumstances or disposition of mind, would be criminal. The rule we have endeavored to prescribe, seems to fulfil this demand of the statute.
Another question remains as to the proof necessary in such cases, and the duty of the jury thereupon.
In this case the court instructed the jury, if the act was proved to their satisfaction, by the weight and preponderance of evidence, to have been one of insanity only, the prisoner was entitled to an acquittal, though the defense should not be proved beyond all reasonable doubt.
This instruction greatly modifies the old rule; but it does not, in our judgment, announce the true principle in criminal cases. In every criminal proceeding before a jury, without any exception, if'a reasonable doubt is entertained of the guilt of the accused, the jury are bound to acquit. Now, what is essential to the commission of a crime ? Our statute declares, to constitute crime, there shall be an union or joint operation of act and intention, or criminal negligence. The overt act is one ingredient, the intention another, and their ; union is indispensable to constitute guilt. Intention is proved . by the' circumstances connected with the perpetration of the ! offense, and the sound mind and discretion of the person accused. The killing alone, under the most aggravated cir- > cumstances, will not suffice, if sound mind and discretion be *393wanting. Sound mind is presumed, if the accused is neither i an idiot, lunatic, “nor affected with insanity.” If he bel affected with insanity, then sound mind is wanting, and crime! is not established. Sound mind, or sanity, then', is an ingre-!j dient in crime, quite as essential as the overt act. Who will! - deny, if there be a reasonable doubt as to the overt act, that! the jury are bound to acquit? Equally imperative must be the rule, if a reasonable doubt be entertained as to the sanity! of the prisoner. Sanity is guilt, insanity is innocence; there-Í fore, a reasonable doubt of the sanity of the accused, on the ? long and well-recognized principles of the common law, must acquit. Suppose the question was one of identity, would not a reasonable, well-founded doubt on the point, acquit the , prisoner? Suppose an alibi was sought to be proved, and proof sufficient was offered, to create a reasonable doubt whether the accused was at the place, and at the time, when and where the offense was alleged to have been committed, is not the prisoner entitled to the benefit of the doubt? So, if the defense be that a homicide was justifiable or excusable, \ is not the principle well settled, a reasonable doubt will : acquit? The rule is founded in human nature, as well as in ‘ the demands of justice and public policy. Innocence is the presumption, guilt being alleged, the State making the charge is bound to proye it ;• the State is bound to produce evidence sufficient to convince the mind of the guilt of the party. If a reasonable doubt is raised, then the mind is not convinced, and being in that unsettled state, whatever the probabilities may be, a jury cannot convict. It is entirely impossible for them to say the accused is guilty, when they entertain a reasonable doubt of his guilt.
It is urged by the prosecution, that the burden of proof is ' on the accused, to make out his defense. That sanity being » the normal condition, insanity must be established by preponderating evidence.
We do not understand the burden of proof is shifted on ] the defendant. Every man charged with crime, is entitled to claim the benefit of all the provisions of the law. In every ! case of murder the first inquiry is, has the homicide been 1 *394• committed — did the prisoner do the deed — did he intend to do it — was he of sound mind and not affected with insanity when the act was done, and was the act done with malice aforethought, express or implied? These are, all of them, affirmative facts, and must be proved by the prosecution. The State avers their existence — they are all essential to constitute the crime, and the State must prove them — the burden of proof is on the State. But it is said, the State is relieved of the burden by proving the prisoner did the act, the law implying that he intended to do it, and that the presumption is, every man is of sound mind. These are but presumptions, and when they are rebutted by proof of absence of criminal intention, by reason of unsoundness of mind, or a reasonable doubt is raised on the point, that doubt must avail the prisoner. Can it be properly said, in criminal cases the burden of proof ever shifts, so long as the defendant bases his defense on the denial of any essential allegation in the indictment? We think not. The prosecution is bound, on every principle of correct pleading, and of justice, to maintain their allegations; and it is not in their power to shift the burden on to the defendant. Commonwealth v. McKie, 1 Gray (Mass.) 61. The presumption of innocence is as strong as the presumption of sanity. The burden of proof must, therefore, always remain with the prosecution to prove guilt beyond a reasonable doubt — a serious and substantial doubt, not the mere possibility of a doubt.
The rule here announced, differs from that laid down in Fisher’s case, 23 Ill. 293. In that case we said, sanity being the normal condition, it must be shown by sufficient proof, that from some cause, it has ceased to be the condition of the accused. The opinion in that case, was prepared under peculiar circumstances not admitting of much deliberation, and this point was not pressed upon the attention of the court, or argued at length. Further reflection has satisfied us, it was too broadly laid down, and that justice and humanity demand, the jury should be satisfied, beyond a reasonable, ] well-founded doubt, of the sanity of the accused. The human mind revolts at the idea of executing a person whose guilt is *395not proved, a well-founded doubt of bis sanity being entertained by the jury.
In these views we are supported by the cases of The State v. Marler, 2 Alabama, 43; The People v. McCann, 2 Smith (N. Y.) 58; Polk v. The State, 12.Ind. 170. Other cases may, no doubt, be found to the same purport. Be the cases few or many, the principle is, nevertheless, correct.
The judgment of the Circuit Court is reversed, the cause remanded, and a venire de novo awarded.