Lunacy (from Lat. luna, the moon). "A lunatic," says Blackstone, "is one that hath had understanding, but by disease, grief, or other accident hath lost the use of his reason; he is indeed properly one that hath lucid intervals, sometimes enjoying his senses and sometimes not, and that frequently depending upon the change of the moon." The common belief in a connection between the accessions of madness and the phases of the moon was long ago exploded, and in medical science lunacy has been displaced by the better terms insanity and mental alienation. In the law, some text writers, following Sir Edward Coke, have preferred non compos mentis as a generic phrase comprehensively descriptive of the various conditions of mental disease or fatuity. "Of unsound mind " has been also much employed in legal language to express certain forms of derangement. But lunacy, though absurd in itself, and in its proper acceptation referring to but a single phase of insanity, has yet gained a more conspicuous place in legal practice than any other term. Statutes, both English and American, have expressly declared that lunatic shall apply to all persons of unsound mind, and to those who are incapable of managing their affairs; and in England the name includes idiots also.

Lunacy may then be fitly employed as a title under which to present the legal relations of insanity. Its medical and scientific aspects are treated under other heads. (See Insanity, and Medical Jurisprudence.) Here Ave concern ourselves only with the settled rules of law, which determine the legal status of insane persons. - In England the custody of lunatics and idiots has until recently been vested in the court of chancery, not in its character of a court of equity, but as the delegate of the crown, the representative of the parens patriae; for it is the duty of the sovereign to take care of those of his subjects who cannot take care of themselves. In the United States the people have succeeded to the rights and prerogatives of the crown, and therefore it is that here the legislature exercises a protective authority over idiots and lunatics. The statutes of the different states provide that such persons may be put under guardianship; and if a competent judicature have in the prescribed mode decided that a person is a lunatic and appointed a guardian, the fact of lunacy is held to be conclusively proved. Until the contrary be shown, either upon an inquisition of lunacy, or upon special testimony in a given case, every man is presumed to be of sane mind.

But if it be proved or admitted that lunacy existed at a particular period, and that the derangement was of a habitual and not of a merely temporary or accidental nature, then it is presumed to continue, unless its continuance be disproved. Thus, in the case of a deed, the burden of proving a grantor's insanity rests ordinarily on him who impeaches the instrument for this cause. Yet, on the other hand, proof of general and usual insanity may be rebutted by evidence that the act was done during a lucid interval, and the burden of proving this rests on the party who asserts the exception. Moral insanity alone, that is, mere derangement of the moral faculties, does not invalidate a will. The evidence must show a delusion in matters of fact. A higher degree of insanity must be shown, in order to absolve from criminal guilt, than to discharge from civil obligation. In some cases it has been held that the jury must be instructed that every man is to be presumed to be, sane, and to possess a sufficient degree of reason to be responsible for his crimes, until the contrary be proved to their satisfaction; and that to establish a defence on the ground of insanity, it must be clearly proved that at the time of the commission of the act, the party accused was laboring under such a defect of reason from disease of the mind as not to know the nature and quality of the act he was doing; or if he did know it, that he did not know he was doing what was wrong.

These were the rules laid down by the judges in McNaughten's case before the house of lords. In Rogers's case in Massachusetts, Chief Justice Shaw instructed the jury that in case of partial insanity the party must have sufficient power of memory to recollect the relation in which he stands to others, and in which others stand to him; and to know that the act he is doing is contrary to the plain dictates of justice and right, injurious to others, and a violation of duty. But, on the contrary, if he still understands the nature of his act and its consequences, if he has a knowledge that it is wrong and criminal, and mental power sufficient to apply that knowledge to his own case, and to know that if he does the act he will do wrong and receive punishment, the partial insanity is not sufficient to exempt him from responsibility for criminal acts. If it be found that the mind of the accused was in a diseased and unsound state, the question will be whether the disease existed to so high a degree that for the time being it overwhelmed all reason, conscience, and judgment, and whether the person in committing the crime acted from an irresistible and uncontrollable impulse.

If so, then the act was not the act of a voluntary agent, but the involuntary act of the body without the concurrence of a mind directing it. Where this view of insanity prevails, such a defence must be substantially proved as an independent fact, and the burden of proof is of course on the defendant. But in other cases it has been declared that the burden is on the prosecution to establish beyond a reasonable doubt all the conditions of guilt, including criminal capacity. Evidence of acts, declarations, and conduct, both before and after the time when the alleged crime was committed, is admissible as tending to show insanity at the moment of the act. Evidence of hereditary insanity is also admissible, both in civil and criminal cases. - Whatever be the nature or degree of mental disease, if the mind be so much impaired as to be incapable of intelligent disposal in the ordinary affairs of life, it is in civil jurisprudence irresponsible for its acts. He whose mind is so far overshadowed possesses no longer a disposing and consenting will. He is therefore incapable of making contracts, for a contract requires a concurrence of wills. When one of the parties to a contract of marriage lacks the capacity of consent, there is no mutually binding promise, and the marriage is void.

Whether, in a given case, such a disability existed as to render the contract impossible, is generally declared and the nullity of the marriage pronounced by competent judicial authority. But though the contracts of an insane man are necessarily void, he has not always been permitted to repudiate them. Until the time of Edward III. no objection seems to have been made to such a proceeding. Afterward the absurd maxim grew into a rule, recognized by the most eminent legal authorities, that no man should be permitted to stultify himself. The strictness of the rule was gradually relaxed; not at first on the ground that lunacy was a defence in itself, but that it was competent evidence to show that undue advantage had been taken of a party, or that actual fraud had been practised upon him, by reason of his imbecility. This rule is now abandoned, and if one enters into a contract while he is deprived of reason he may avoid it when he recovers his sanity. Yet the exception is admitted that one may not plead his lunacy to annul his contract for necessaries made with him in good faith by the other party; nor if, in fact, no advantage were taken of the lunatic, can a purchase made in good faith be rescinded, if injustice would thus be wrought to the other party, and both cannot be placed in statu quo. - A testament discloses the will of the testator; but when a disposing will fails, a testament is impossible, and the waiting which purports to be one is a nullity.

It is naturally very difficult to prove the existence of a lucid interval; far more difficult than to prove the existence of general insanity. It is sufficient for the purposes of the law that the mind appears to have been rational when the will was made. Indeed, the will itself may furnish strong, perhaps the best evidence of the lucid interval. If testimony can be adduced to show that the act was done without any assistance, and the writing itself discloses no marks of delusion or folly, no further proof can generally at least be required. - It has been already stated that the same degree of incapacity which invalidates civil acts, does not exempt from criminal responsibility. When insanity is pleaded to a charge of crime, the real question which the law entertains is: Was there a criminal intent? was the accused capable of that criminal will which is the essence of the offence ? From the nature of the case the law has found it difficult to answer these questions; and perhaps it has not always answered them well. The doctrine of Sir Matthew Hale has exerted a large influence on the course of English decisions.

He was disposed to determine the criminal responsibility of a mind affected with insanity by its strength and capacity; and said: "Such a person as, while laboring under melancholy distempers, hath yet ordinarily as great understanding as usually a child of 14 years old hath, is such a person as may be guilty of treason or felony." But such a rude test could not be permitted when juster views of mental disease had come to prevail among scientific men; and accordingly we find the nicety of the test a little advanced when the inquiry became whether the accused had so far lost the use of his understanding as not to know right from wrong. With the single qualification that this test should be applied to the particular act committed, this criterion has been long in use, with only slight and immaterial variations, in the English criminal law. It was laid down in Bellingham's case, by Sir James Mansfield, in 1812. In that case the court went to what is now considered an extreme length, and instructed the jury that if a person affected by that species of insanity in which the patient fancies the existence of injury and seeks an opportunity of gratifying his revenge by some hostile act, be yet capable in other respects of distinguishing right from wrong, this would be no excuse for any act of violence which he might commit under this species of derangement.

So Baron Rolfe, in the case of the queen against Stokes in 1848 (and he was quoted and followed by Baron Parke in Barton's case in the same year), said the subject had been lately carefully considered by the judges, and the law was now clear; every man is responsible for his acts by the law of his country if he can discern right from wrong. In the trial of Pate (1850) for an assault upon the queen, in which an uncontrollable impulse was urged in defence, Baron Alderson said in summing up: " 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 species of insanity which excuses a man for his acts is that species of delusion which induced to, and drove him to the commission of the act alleged against him. The jury ought to have clear proof of a formed disease of the mind; a disease existing before the act was done, and which made the accused incapable of knowing at the time that it was a wrong act which he was about to commit. The law does not acknowledge the doctrine of an uncontrollable impulse, if the person was aware that the act which he contemplated was wrong.

The question you have to decide is: Was the accused at the time suffering from a disease of the mind which rendered him incapable of judging whether the act he committed was a right or a wrong act ? " In one class of cases the test of responsibility is therefore to be, whether the prisoner knew that the act which he committed was wrong, and right and wrong in these cases are probably to be understood as Lord Brougham explained them in McNaughten's case, viz.: right must be understood of right according to the law, and wrong of an act condemned and punishable by law. - Another class of cases is that in which responsibility is modified by the existence of delusion. This form of insanity was first brought before and recognized by the courts in the celebrated case of Hatfield in 1800. In that case the prisoner was put upon his trial for firing at the king. Mr. Erskine defended him successfully, and procured the acquiescence of the court in his views of the irresponsibility of the accused. Hatfield labored under the delusion that it was his duty to sacrifice himself for his fellow men, and he conceived that the best mode to draw upon himself the punishment of death was to make an attempt upon the life of his sovereign.

It was not denied that Hatfield knew right from wrong, and that the act which he contemplated was punishable by the law; indeed, it was just that which he did know and directly contemplated; yet so powerful was his delusion, that the act which it prompted could not be said to proceed from the motion of his own free will. So clearly and forcibly did Mr. Erskine present the grounds of the defence, that the court, Lord Kenyon, advised the withdrawal of the prosecution, and the argument of the eminent counsel became a precedent and authority in the law. This same plea of delusion was successfully urged for Martin, who set fire to the minster of York, in obedience, as he said, to the command of Heaven. In 1843 the English law upon this matter was set forth in the case of McNaughten by the judges in the house of lords. The judges say that if there be only a partial delusion, and the party is not in other respects insane, he must be considered in the same situation as, to responsibility as if the facts with respect to which the delusion exists were real. For example, if, under the influence of such a delusive idea, one supposes another to be in the act of attempting to take his life, and he kills that other, as he supposes in self-defence, then he would be exempt from punishment.

But if the delusion were that the deceased had inflicted a serious injury upon his character and fortune, and he therefore killed him in revenge, then the aggressor must be held guilty. It was also the opinion of the judges that, notwithstanding a party accused did an act which was in itself criminal under the influence of insane delusion, with a view of producing some public benefit, or of redressing some supposed wrong, yet he was responsible if he knew that he was acting contrary to the law of the land. In Massachusetts, in the well known case of Rogers, delusion was admitted to be a legal test of insanity. It was there held that if a party under a real and firm though insane belief do an act which would be justifiable if the imaginary fact existed, then he is not responsible. - The tests already considered, namely, the consciousness of right and wrong, and delusion, apply to the intellectual faculties alone. But the moral faculties, not less than the intellectual, may become deranged. Passions and propensities may be so extremely developed as to destroy the balance of the mind and defeat the supremacy of the will. This condition of mental disorder, moral insanity, as it is called, has received a partial recognition by the law.

The nicer degrees of it, for which medical men contend, have not found so much favor in the eyes of the courts. When the claim of indulgence for this sort of mental infirmity has been plainly reasonable, it has however been admitted and favored. This has been the case in respect to that form of insanity known as homicidal mania. The perpetrator may be perfectly capable of distinguishing right from wrong, not only abstractly, but also in reference to the particular act. Further, there may be, in fact generally is, no delusion in respect to the victim. The act is the offspring of an uncontrollable impulse; the party knows the nature of the act which he is about to commit, but has not the power to choose otherwise than as he does; and because the will is not here concerned, the homicide is not answerable for his act. - So far then as adjudicated cases go, insanity is admitted as a good plea: 1, when at the commission of the act the offender was incapable of distinguishing whether it was right or wrong; 2, when the act was done under a delusion in respect to the existence of facts which, had they actually existed, would have constituted a good defence; and 3, if the act were committed under the influence of mental disease great enough to overpower the will, though neither delusion nor any like provocation of the act be discovered.

But it is not to be denied that the whole subject is surrounded by. difficulties which lead to the most startling anomalies in practice. Mr. Bishop, in his treatise on criminal law (§ 474), well says: "The labors of writers on insanity have been exhausted in attempts to find some test of ready application to determine when a person is to be deemed insane, and when not, in reference to his responsibility for crime. And judges, less informed on this subject than on most other subjects of legal science, have struggled under the inherent embarrassments of the question itself, under the influence of erroneous notions in the community, and under the failures of counsel and witnesses in particular cases to present the real points of inquiry. The result has been that instructions given in reference to particular facts appearing in the cases before them have seemed to casual observers' to be very discordant, while to scientific inquirers after the facts of insanity they have seemed very absurd." The conflicting views of scientific men regarding the tests of insanity, which enable parties in all important cases to bewilder the jury with conflicting testimony of experts, have done much to discredit unjustly all expert testimony; and the resort to the defence of insanity when homicide has been committed in revenge for actual or pretended domestic wrongs, has thrown suspicion and discredit on the defence generally.

Besides the English and Massachusetts cases referred to above, and which have considered the subject of criminal capacity in persons insane or laboring under delusion, the important cases of Freeman v. People, 4 Denio, 9; Commonwealth v. Mosler, 4 Penn. State R., 267; Flanagan v. People, 52 New York, 467; State v. Spencer, 1 Zabriskie (N. J.), 196; State v. Felter, 25 Iowa, 67; and State v. Jones, 50 N. H., 369, may be named, which however, in some particulars, are wholly irreconcilable with each other or with the English cases. The tendency of decision has been in the direction of giving more latitude to the jury in judging of the symptoms and tests of mental disease; and this culminated in the trial of Cole in New York, for the murder of one whom he charged with adultery with his wife, in which the jury, in substance, found that the accused was insane at the moment of committing the act, but sane immediately before and immediately afterward.